WO1997023537A1 - Compositions de revetement contenant des resines qui comportent des groupes amines, et resines dudit type - Google Patents

Compositions de revetement contenant des resines qui comportent des groupes amines, et resines dudit type Download PDF

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Publication number
WO1997023537A1
WO1997023537A1 PCT/US1996/019793 US9619793W WO9723537A1 WO 1997023537 A1 WO1997023537 A1 WO 1997023537A1 US 9619793 W US9619793 W US 9619793W WO 9723537 A1 WO9723537 A1 WO 9723537A1
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WIPO (PCT)
Prior art keywords
group
composition
amine
ketone
groups
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PCT/US1996/019793
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English (en)
Inventor
Raphael O. Kollah
Gregory J. Mccollum
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Ppg Industries, Inc.
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Publication of WO1997023537A1 publication Critical patent/WO1997023537A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/72—Polyisocyanates or polyisothiocyanates
    • C08G18/80—Masked polyisocyanates
    • C08G18/8061—Masked polyisocyanates masked with compounds having only one group containing active hydrogen
    • C08G18/8064—Masked polyisocyanates masked with compounds having only one group containing active hydrogen with monohydroxy compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/08—Processes
    • C08G18/0804—Manufacture of polymers containing ionic or ionogenic groups
    • C08G18/0809—Manufacture of polymers containing ionic or ionogenic groups containing cationic or cationogenic groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/64—Macromolecular compounds not provided for by groups C08G18/42 - C08G18/63
    • C08G18/6415—Macromolecular compounds not provided for by groups C08G18/42 - C08G18/63 having nitrogen
    • C08G18/643—Reaction products of epoxy resins with at least equivalent amounts of amines
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/44—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
    • C09D5/4419—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications with polymers obtained otherwise than by polymerisation reactions only involving carbon-to-carbon unsaturated bonds
    • C09D5/443—Polyepoxides
    • C09D5/4434—Polyepoxides characterised by the nature of the epoxy binder

Definitions

  • the present invention relates to coating compositions, such as cationic electrodepositable compositions, and to their use in electrodeposition and amine- group-containing resins like those with ketimine groups as components for coating compositions.
  • Coating compositions have been applied to substrates by spraying, dipping, brushing and by electrodeposition for particular types of coating compositions .
  • the application of a coating by electrodeposition involves depositing a film-forming composition to an electrically conductive substrate under the influence of an applied electrical potential.
  • Electrodeposition has gained prominence in the coatings industry because in comparison with non-electrophoretic coating methods, electrodeposition provides higher paint utilization, outstanding corrosion resistance, and decreased environmental concerns.
  • early attempts at commercializing electrodeposition coating processes used anionic electrodeposition, cationic electrodeposition, with the substrate to be coated as the cathode, was introduced commercially in 1972. Since that time cationic electrodeposition has become increasingly popular and today is a prevalent method of electrodeposition.
  • cationic electrodeposition compositions used today are based on active hydrogen-containing resins such as amine group-containing resins derived from a polyepoxide and a capped polyisocyanate curing agent.
  • the amine groups are typically introduced into the polyepoxide via reaction of the polyepoxide with a polyamine having at least one primary amine group which is blocked as a ketimine group.
  • the ketimine is formed by reacting the polyamine with a ketone, such as methyl isobutyl ketone, in which the carbons attached to the carbonyl carbon of the ketone are primary carbons.
  • compositions comprising an amine group- containing resin, which can be prepared with improved control of the molecular weight, derived from materials which are readily prepared in high yields that contribute to good film build characteristics for electrodepositable coating formulations.
  • a curable coating composition has (a) at least one non-gelled amine group-containing resin and (b) at least one capped polyisocyanate curing agent.
  • the amine group-containing resin has at least a portion of the amine groups as primary amine groups and is formed by reacting: a) an epoxy group-containing material; and b) an amine derivative having at least one group which is reactive with epoxy groups and at least one primary amine group which is blocked as a ketimine group through reaction of the primary amine group with a ketone in which the carbons attached to the carbonyl carbon of the ketone are secondary carbons.
  • the coating composition can have an aqueous or organic solvent carrier.
  • the aqueous coating composition includes the amine group-containing resin which has been at least partially neutralized with acid. Such a resin rendered cationic by neutralization is suitable in the aqueous coating composition that is an electrodepositable coating.
  • the curable non-gelled amine group-containing resin is provided through reaction of the epoxy group-containing material with the amine derivative.
  • suitable epoxy group-containing material includes polyepoxide having an epoxide equivalent weight in the range of 100 to 2000 and/or having chain extension.
  • coating composition means coating compositions that can be applied to substrates such as exterior and interior surfaces of metal, plastic, wood, or paper for protective and/or decorative purposes.
  • coating compositions include automotive paints, primers and surface treatments; exterior and interior paint; varnish; lacquer; enamels; printing ink; and the like.
  • Such a coating composition is distinguished from an adhesive which is a composition capable of bonding or securing two already formed solid substrates together, where upon an attempt to cause physical separation of each of those solid substrates, the adhesion of those substrates is sufficiently great that cohesive failure occurs (i.e., physical failure, such as tearing, of at least one substrate occurs).
  • the curable, non-gelled amine group-containing resin is formed from at least two reactants, where one of the reactants is the epoxy group-containing material.
  • Any suitable epoxy group-containing material, epoxy compounds or preferably a polyepoxide known to those skilled in the art may be used.
  • the epoxy compounds may be saturated or unsaturated, cyclic or acyclic, aliphatic, alicyclic, aromatic or heterocyclic. They may contain substituents such as halogen, hydroxyl, and ether groups.
  • polyepoxides are those having a 1,2-epoxy equivalency greater than one and preferably about two, that is, polyepoxides which have on the average two epoxide groups per molecule.
  • the preferred polyepoxides are polyglycidyl ethers of cyclic polyols. Particularly, preferred are polyglycidyl ethers of polyhydric phenols such as Bisphenol A. These polyepoxides can be produced by etherification of polyhydric phenols with an epihalohydrin or dihalohydrin such as epichlorohydrin or dichlorohydrin in the presence of alkali.
  • cyclic polyols can be used in preparing the polyglycidyl ethers of cyclic polyols.
  • examples of other cyclic polyols include alicyclic polyols, particularly cycloaliphatic polyols such as a 1,2-cyclohexane diol and a 1,2- bis(hydroxymethyl)cyclohexane.
  • Further examples of the polyepoxide polymers with molecular weights of around 180 to 2000 generally are shown in U S.
  • the preferred polyepoxides have number average molecular weights ranging from about 180 to 500, and most preferably from about 186 to 350. In general, the epoxide equivalent weight of the polyepoxide will range from 100 to about 2000 and preferably from about 180 to 500.
  • Epoxy group-containing acrylic polymers such as those of U.S. Patent 4,001 ,156 in columns 3-6 can also be used but they are not preferred.
  • epoxy equivalent weight denotes the reciprocal of the equivalents of the epoxy groups contained per gram of an epoxy compound and can be measured by any known determination method. Examples of these include infrared (IR) spectroscopy or the HCl-pyridine titration method through reaction with excess HCl in pyridine and titration of the remaining HCl with sodium methoxide, or titration in chloroform with perchloric acid in the presence of excess tetraethylammonium bromide and glacial acetic acid with an indicator of crystal violet (hexamethyl pararosaniline chloride, or by titrating a sample of the reaction product with tetrabutylammonium iodide and perchloric acid).
  • IR infrared
  • HCl-pyridine titration method through reaction with excess HCl in pyridine and titration of the remaining HCl with sodium methoxide
  • chloroform with perchloric acid in the presence of excess
  • Chain-extended polyepoxide polymers can also be used and are preferred.
  • chain extension can be by reacting together a polyepoxide and a polyhydroxyl group-containing material selected from alcoholic hydroxyl group- containing materials and phenolic hydroxyl group-containing materials to chain extend or build the molecular weight of the polyepoxide.
  • a chain-extended polyepoxide may be prepared by any method known to those skilled in the art and is typically prepared by reacting together the polyepoxide and polyhydroxyl group- containing material neat 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 the dimethyl ether of diethylene glycol.
  • the reaction is usually conducted at a temperature of about 80°C to 160°C for about 30 to 180 minutes until an epoxy group-containing resinous reaction product is obtained.
  • the equivalent ratio of reactants i.e.
  • epoxy :polyhydroxyl group-containing material is typically from about 1:0.75 to 1 :2.
  • polyhydroxyl group-containing materials used to chain extend or increase the molecular weight of the polyepoxide include alcoholic hydroxyl group-containing materials and phenolic hydroxyl group-containing materials.
  • alcoholic hydroxyl group-containing materials are simple polyols such as neopentyl glycol; polyester polyols such as those described in U.S. Patent 4,148,772; polyether polyols such as those described in U.S. Patent 4,468,307; and urethane diols such as those described in U.S. Patent 4,931,157, all of which are inco ⁇ orated by reference for these teachings.
  • phenolic hydroxyl group-containing materials are polyhydric phenols such as Bisphenol A, phloroglucinol, catechol, and resorcinol. Mixtures of alcoholic hydroxyl group-containing materials and phenolic hydroxyl group-containing materials may also be used. Bisphenol A is preferred.
  • the curable non-gelled amine group-containing resin of the present invention is prepared by reacting the epoxy group-containing material described above with an amine derivative, yielding a resin wherein at least a portion of the amine groups are primary amine groups.
  • the equivalent ratio of reactants, i.e., epoxy group- containing material to amine derivative is typically from about 1:0.75 to about 1 :1.1.
  • non-gelled means that the resin is substantially free from crosslinking, and the resin has a measurable intrinsic viscosity when dissolved in a suitable solvent.
  • the intrinsic viscosity of the reaction product is an indication of its molecular weight.
  • a gelled reaction product since it is of essentially infinitely high molecular weight, will have an intrinsic viscosity too high to measure.
  • the amine derivative has at least one group which is reactive with epoxy groups and at least one primary amine group which is blocked as a ketimine group, hereinafter referred to as "amine derivative" .
  • the ketimine group is formed through reaction of the primary amine group with a ketone in which the carbons attached to the carbonyl carbon of the ketone are secondary carbons.
  • the reaction of the amine derivative with the polyepoxide takes place upon mixing of the amine derivative and polyepoxide. Either the amine derivative or the polyepoxide can be added one to the other.
  • the reaction can be conducted 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 and cooling may be desired. However, heating to a moderate temperature of about 50°C to 150°C may be done lo ensure a complete reaction.
  • the reaction is conducted in the absence of oxygen, for example, under a nitrogen blanket or in a nitrogen atmosphere.
  • the amine derivative is prepared by reacting a polyamine with a ketone.
  • the equivalent ratio of reactants i.e. , polyamine to ketone is typically from about 1:1 to 1:4.
  • the amine derivative may be prepared by adding either the ketone or the polyamine one to the other.
  • Typical reaction conditions include a temperature range of about 80°C to 200°C and pressures of about 20 to 760 millimeters (mm) of mercury (Hg) (27 to 1013 Newton/meter 2 ).
  • the reaction is conducted in the absence of oxygen, for example under a nitrogen blanket or in a nitrogen atmosphere.
  • the polyamine reactant may be virtually any polyamine capable of reacting with an epoxy group, generally having at least one secondary amine group and containing primary amine groups. Mixtures of such various amines can also be used.
  • the preferred polyamines are the alkylene polyamines and substituted alkylene polyamines.
  • the especially preferred polyamines are selected from those having the following formula: where R 1 and R 2 are independently difunctional aliphatic groups containing from about 2 to 28 carbon atoms. R 1 and R 2 may represent the same or different radicals in any one polyamine compound. Inert and non- interfering groups as known by those skilled in the art may be present on the R 1 and/or R 2 groups. Examples of inert groups include, inter alia, those which do not contain an active hydrogen or other moiety capable of reaction with an epoxide or carbonyl group.
  • Preferred polyamines are those having the formula above wherein R 1 and R 2 are independently difunctional aliphatic hydrocarbon groups. It is particularly preferred that R 1 and R 2 be alkylene groups of 2 to 6 carbon atoms. Typical amines which may be used are diethylene triamine, which is most preferred, triethylene tetramine, and the like, and corresponding propylene, butylene, and higher alkylene amines. Other suitable amines include primary-secondary amines such as N -amino ⁇ ethyl piperizine. The primary amine groups of the polyamines are converted to ketimines by reaction with ketones in which the carbons attached to the carbonyl carbon of the ketone are secondary carbons.
  • ketones examples include diisopropyl ketone, dicyclohexyl ketone, and 2,6-dimethylcyclohexanone.
  • Diisopropyl ketone is preferred.
  • the ketimine groups decompose upon dispersing the amine -epoxy resin reaction product in water.
  • the non-gelled amine group-containing resin alternatively referred to as an polyepoxide-amine adduct, as the reaction product of the amine derivative and the polyepoxide may be made cationic and water dispersible for use in an aqueous coating composition such as an electrodepositable composition. This is accomplished by deblocking of the ketimine groups to reform primary amine groups and/or at least partial neutralization with an acid to form cationic salt groups by any method known to those skilled in the art. Suitable acids include organic and inorganic acids such as formic acid, acetic acid, lactic acid, phosphoric acid and sulfamic acid. Sulfamic acid is preferred. The extent of neutralization varies with the particular reaction product involved.
  • sufficient acid should be used to at least disperse the amine group-containing resin for use as an electrodepositable composition in water.
  • the amount of acid used provides at least 20 percent of all of the total neutralization. Excess acid may also be used beyond the amount required for 100 percent total neutralization.
  • the extent of cationic salt group formation should be such that when the resin is mixed with an aqueous medium and the other ingredients, a stable dispersion of the electrodepositable composition will form.
  • stable dispersion is meant one that does not settle or is easily redispersible if some settling occurs.
  • the dispersion should be of sufficient cationic character that the dispersed particles will migrate toward and electrodeposit on a cathode when an electrical potential is set up between an anode and a cathode immersed in the aqueous dispersion.
  • the amine group-containing cationic resin of the electrodepositable composition of the present invention is non-gelled and contains from about 0.1 to 3.0, preferably from about 0.1 to 0.7 milliequivalents of cationic salt group per gram of resin solids.
  • the number average molecular weight of the amine group-containing cationic resin preferably ranges from about 2,000 to about 15,000, more preferably from about 5,000 to about 10,000.
  • non- gelled additionally refers to the resin having a measurable intrinsic viscosity when dissolved in a suitable solvent prior to cationic salt group formation.
  • the amine group-containing cationic resin may contain other active hydrogens which are reactive with isocyanates within the temperature range of about 93°C to 204°C, preferably about 121 °C to 177°C, as are known to those skilled in the art. Most often, the other active hydrogens are selected from the groups consisting of hydroxyl and secondary amino, including mixtures thereof.
  • the amine group-containing cationic resin will have an active hydrogen content of about 1.7 to 10 milliequivalents, more preferably about 2.0 to 5 milliequivalents of active hydrogen per gram of resin solids.
  • the amine group-containing cationic resin as component (a) is present in the coating composition, preferably the electrodepositable coating composition, in amounts of 15 to 85, preferably 40 to 70 percent by weight based on weight of main vehicle resin solids.
  • main vehicle resin solids is meant resin solids attributable to the amine group-containing resin, or preferably cationic resin, of component (a) and the polyisocyanate curing agent as component (b) of a coating composition.
  • the coating composition and preferably the electrodepositable composition of the present invention also contains a capped polyisocyanate curing agent (component (b)).
  • the polyisocyanate curing agent may be a fully capped polyisocyanate with substantially no free isocyanate groups, or it may be partially capped and reacted with the resin backbone as described in U.S. Patent 3,984,299, which is hereby inco ⁇ orated by reference regarding capped polyisocyanates.
  • the polyisocyanate can be an aliphatic or an aromatic polyisocyanate or a mixture of the two. Diisocyanates are preferred, although higher polyisocyanates can be used in place of or in combination with diisocyanates.
  • Suitable aliphatic diisocyanates are straight chain aliphatic diisocyanates such as 1,4-tetramethylene diisocyanate and 1,6-hexamethylene diisocyanate.
  • cycloaliphatic diisocyanates can be employed. Examples include isophorone diisocyanate and 4,4'-methylene-bis-(cyclohexyl isocyanate).
  • suitable aromatic diisocyanates are p-phenylene diisocyanate, diphenylmethane-4,4' -diisocyanate and 2,4- or 2,6-toluene diisocyanate.
  • suitable higher polyisocyanates are triphenylmethane-4,4' ,4"-triisocyanate; 1 ,2,4-benzene triisocyanate and polymethylene polyphenyl isocyanate.
  • Isocyanate prepolymers for example, reaction products of polyisocyanates with polyols such as neopentyl glycol and trimethylol propane or with polymeric polyols such as polycaprolactone diols and triols (NCO/OH equivalent ratio greater than one) can also be used.
  • polyols such as neopentyl glycol and trimethylol propane
  • polymeric polyols such as polycaprolactone diols and triols (NCO/OH equivalent ratio greater than one)
  • NCO/OH equivalent ratio greater than one NCO/OH equivalent ratio greater than one
  • a mixture of diphenylmethane-4, 4 '-diisocyanate and polymethylene polyphenyl isocyanate is preferred.
  • Any suitable aliphatic, cycloaliphatic, or aromatic alkyl monoalcohol or phenolic compound may be used as a capping agent for the capped polyisocyanate curing agent in the coating composition and preferably electrodepositable composition of the present invention.
  • these include, for example, lower aliphatic alcohols .such as methanol, ethanol, and n-butanol; cycloaliphatic alcohols such as cyclohexanol; aromatic-alkyl alcohols such as phenyl carbinol and methylphenyl carbinol; and phenolic compounds such as phenol itself and substituted phenols wherein the substituents do not affect coating operations, such as cresol and nitrophenol.
  • lower aliphatic alcohols such as methanol, ethanol, and n-butanol
  • cycloaliphatic alcohols such as cyclohexanol
  • aromatic-alkyl alcohols such as phenyl carbinol and methylpheny
  • Glycol ethers may also be used as capping agents.
  • Suitable glycol ethers include ethylene glycol butyl ether, diethylene glycol butyl ether, ethylene glycol methyl ether and propylene glycol methyl ether. Diethylene glycol butyl ether is preferred among the glycol ethers.
  • capping agents include oximes such as methyl ethyl ketoxime, acetone oxime and/or cyclohexanone oxime, lactams such as epsilon-caprolactam, and amines such as dibutyl amine. 3537
  • the capped polyisocyanate curing agent is typically present in the coating composition and preferably the electrodepositable composition in amounts of 15 to 85 , preferably 30 to 60 percent by weight based on weight of main vehicle resin solids. Typically, there is sufficient polyisocyanate present in the coating composition electrodepositable composition of the present invention to provide about 0.1 to about 1.2 capped isocyanate groups for each active hydrogen in the cationic resin.
  • the coating composition is an electrodepositable composition which may be formulated so as to be substantially free of lead, and comprises:
  • an acid-neutralized (i.e., cationic), amine group-containing resin wherein at least a portion of the amine groups are primary amine groups and wherein the amine group-containing resin is formed by reacting: a) an epoxy group-containing material; and b) an amine derivative having at least one group which is reactive with epoxy groups and at least one primary amine group which is blocked as a ketimine group through reaction of the primary amine group with a ketone in which the carbons attached to the carbonyl carbon of the ketone are secondary carbons, and present as a separate component; (2) a fully capped polyisocyanate curing agent containing substantially no free isocyanate groups.
  • an acid-neutralized (i.e., cationic), amine group-containing resin wherein at least a portion of the amine groups are primary amine groups and wherein the amine group-containing resin is formed by reacting: a) an epoxy group-containing material; and b) an amine derivative having at least one group which is
  • the electrodepositable composition further contains from about 0.02 to 1 milliequivalents (meq.) phenolic hydroxyl groups per gram of main vehicle resin solids, and from about 0.1 to 2 meq. beta-hydroxy ester groups per gram of main vehicle resin solids.
  • the phenolic hydroxyl groups and beta-hydroxy ester groups present in the composition may be present in any combination in component (1) and/or component (2).
  • both groups may be present in component (1), both groups may be present in component (2), both groups may be present in both components, or one or both types of groups may be present in component (1) while the other (or both) is in component (2).
  • components (1) and (2) need not contain the phenolic hydroxyl groups and beta- hydroxy ester groups present in the composition.
  • the phenolic hydroxyl groups and beta-hydroxy ester groups may be present in a third and/or fourth component different from (1) and (2).
  • the acid-neutralized, amine group-containing resin of component (1) may further contain active hydrogen groups selected from aliphatic hydroxyl, secondary amino, and mixtures thereof.
  • Beta-hydroxy ester groups may be inco ⁇ orated into component (1) by ring opening 1 ,2-epoxide groups of the epoxy group-containing material with a material which contains at least one carboxylic acid group.
  • the carboxylic acid functional material may be a monobasic acid such as dimethylolpropionic acid, malic acid, and 12-hydroxystearic acid; a polybasic acid such as a simple dibasic acid or the half ester reaction products of a polyol and the anhydride of a diacid, or a combination thereof.
  • a monobasic acid it preferably has hydroxyl functionality associated with it.
  • Suitable polybasic acids include succinic acid, adipic acid, citric acid, and trimellitic acid. If a polybasic acid is used, care must be taken to prevent gelation of the reaction mixture by limiting the amount of polybasic acid and/or by additionally reacting a monobasic acid.
  • Suitable half ester reaction products include, for example, the reaction product of trimethylolpropane and succinic anhydride at a 1: 1 equivalent ratio.
  • Suitable hydroxyl group-containing carboxylic acids include dimethylolpropionic acid, malic acid, and 12-hydroxystearic acid. Dimethylolpropionic acid is preferred.
  • Phenolic hydroxyl groups may be inco ⁇ orated into component (1) by using a stoichiometric excess of the polyhydric phenol during initial chain extension of the epoxy group-containing material. Although a stoichiometric excess of phenolic hydroxyl groups to epoxy is used, there still remains unreacted epoxy groups in the resulting resinous reaction product for subsequent reaction with the amine derivative. It is believed that a portion of polyhydric phenol remains unreacted. Therefore, where it is mentioned that component (1) contains unreacted phenolic groups, a resinous mixture comprising a resin having active hydrogen groups such as aliphatic hydroxyl and primary or secondary amino groups and cationic salt groups in admixture with a polyhydric phenol is meant to be included.
  • the phenolic hydroxyl groups may be inco ⁇ orated simultaneously with the beta-hydroxy ester groups, or sequentially before or after.
  • the phenolic hydroxyl groups are inco ⁇ orated into component (1) after inco ⁇ oration of the beta-hydroxy ester groups by reacting a stoichiometric excess of polyhydric phenol with the resulting polyepoxide.
  • Beta-hydroxy ester groups may be inco ⁇ orated into component (2) by reacting the isocyanate groups of the polyisocyanate with the hydroxyl group of a hydroxyl group-containing carboxylic acid such as dimethylolpropionic acid, malic acid, and 12-hydroxy stearic acid. Dimethylolpropionic acid is preferred.
  • the acid group on the hydroxyl group-containing carboxylic acid is reacted (either before or after reaction of the isocyanate group with the hydroxyl group) with an epoxy functional material such as a monoepoxide or polyepoxide, with ring opening of a 1 ,2-epoxide group on the epoxy functional material to form the beta-hydroxy ester group.
  • monoepoxides which may be used include ethylene oxide, propylene oxide, 1,2-butylene oxide, 1,2-pentene oxide, styrene oxide, and glycidol.
  • monoepoxides include glycidyl esters of monobasic acids such as glycidyl acrylate, glycidyl methacrylate, glycidyl acetate, glycidyl butyrate; linseed glycidyl ester and glycidyl ethers of alcohols and phenols such as butyl glycidyl ether and phenylglycidyl ether.
  • polyepoxides which may be used to form the beta-hydroxy ester groups in component (2) are those having a 1 ,2-epoxy equivalency greater than one and preferably about two; that is, polyepoxides which have on average two epoxide groups per molecule.
  • the preferred polyepoxides are polyglycidyl ethers of cyclic polyols. Particularly preferred are polyglycidyl ethers of polyhydric phenols such as Bisphenol A.
  • Phenolic hydroxyl groups may be inco ⁇ orated into component (2) by capping the isocyanate groups with phenolic materials having an aliphatic and a phenolic hydroxyl group such as 2-hydroxybenzyl alcohol. The isocyanate group will react preferentially with the aliphatic hydroxyl group. It is also possible to inco ⁇ orate phenolic hydroxyl groups into component (2) by capping the isocyanate groups with a hydroxyl functional polyepoxide such as a polyglycidyl ether of a cyclic polyol or polyhydric phenol, which is further reacted with a stoichiometric excess of a polyhydric phenol.
  • a hydroxyl functional polyepoxide such as a polyglycidyl ether of a cyclic polyol or polyhydric phenol
  • Beta-hydroxy ester groups may alternatively be inco ⁇ orated into Ihe electrodepositable composition of the present invention by a third component (3) which is different from (1) and (2).
  • a component may be a reaction product of an epoxy functional material, such as a polyepoxide, typically those mentioned above, and a carboxylic acid functional material.
  • Suitable carboxylic acid functional materials include dimethylolpropionic acid, tartaric acid, or the product of a polyol or polyamine reacted with the anhydride of a polybasic acid. Examples include ethylene glycol or ethylene diamine reacted with a succinic anhydride.
  • Component (3) may further include free phenolic hydroxyl groups.
  • these may be inco ⁇ orated by reacting a portion of the epoxy functional material with a carboxylic acid functional material as mentioned above and then 23537
  • Free phenolic hydroxyl groups may also be inco ⁇ orated into the composition of the present invention by a fourth component (4) which is different than the other components.
  • Suitable components include polymers and/or copolymers of hydroxyl functional styrene monomers such as poly-p-hydroxy styrene, and a polyepoxide, as mentioned above, reacted with a stoichiometric excess of a polyhydric phenol, a phenol-formaldehyde condensation product, or polymers and/or copolymers of hydroxyl functional styrenic monomers such as poly-p-hydroxy styrene.
  • the free phenolic hydroxyl groups are present in the electrodepositable composition in amounts of about 0.02 to 1 milliequivalents, preferably about 0.07 to 0.30 milliequivalents per gram of resin solids, the unreacted phenolic hydroxyl groups calculated as:
  • the beta-hydroxy ester groups are present in the electrodepositable composition in amounts of about 0.1 to 2 milliequivalents, preferably about 0.3 to 0.8 milliequivalents per gram of resin solids, the beta-hydroxy ester groups calculated as:
  • the electrodepositable composition of the present invention is preferably used in an electrodeposition process in the form of an aqueous dispersion.
  • aqueous dispersion is meant a two-phase transparent, translucent, or opaque aqueous resinous system in which the resin, curing agent, pigment, and water insoluble materials are the dispersed phase and water and water soluble materials comprise the continuous phase.
  • the dispersed phase has an average particle size less than about 10 microns, preferably less than 5 microns.
  • the aqueous dispersion preferably contains at least about 0.05 and usually about 0.05 to 50 percent by weight resin solids, depending on the particular end use of the dispersion.
  • the aqueous dispersion may optionally contain a coalescing solvent such as hydrocarbons, alcohols, esters, ethers and ketones.
  • a coalescing solvent such as hydrocarbons, alcohols, esters, ethers and ketones.
  • preferred coalescing solvents are alcohols, including polyols, such as isopropanol, butanol, 2-ethylhexanol, ethylene glycol and propylene glycol; ethers such as the monobutyl and monohexyl ethers of ethylene glycol; and ketones such as 4-methyl-2-pentanone (MIBK) and isophorone.
  • the coalescing solvent is usually present in an amount up to about 40 percent by weight, preferably ranging from about 0.05 to 25 percent by weight based on total weight of the aqueous medium.
  • the electrodepositable composition of the present invention may further contain pigments and various other optional additives such as catalysts, plasticizers, surfactants, wetting agents, de
  • Suitable surfactants and wetting agents include alkyl imidazolines such as those available from Geigy Industrial Chemicals as GEIGY AMINE C, and acetylenic alcohols available from Air Products and Chemicals as SURFYNOL.
  • defoamers include a hydrocarbon containing inert diatomaceous earth available from Crucible Materials Co ⁇ . as FOAMKILL 63.
  • anti-cratering agents are polyoxyalkylene-polyamine reaction products such as those described in U.S. Patent 4,432,850. Other examples are those shown in U.S. Patents 5,356,529; 5,260,135; and 5,260,354.
  • Curing catalysts preferably tin catalysts such as dibutyltin dilaurate and dibutyltin oxide, are usually present in the electrodepositable composition of the present invention. When present, they are used in amounts of about 0.05 to 5 percent by weight based on weight of main vehicle resin solids.
  • Suitable pigments include, for example, iron oxides, carbon black, coal dust, titanium dioxide, talc and barium sulfate. Lead pigments may also be used.
  • the pigment content of the aqueous dispersion generally expressed as the pigment to resin (or binder) ratio (P/B) is usually about 0.1 : 1 to 1:1.
  • Electrodeposition In the process of electrodeposition, the aqueous dispersion is placed in contact with an electrically conductive anode and cathode, i.e., the substrate to be coated. Upon passage of an electric current between the anode and cathode while they are in contact with the aqueous dispersion, an adherent film of the electrodepositable composition will deposit in a substantially continuous manner on the cathode. Electrodeposition is usually carried out at a constant voltage in the range of from about 1 volt to several thousand volts, typically between 50 and 500 volts.
  • Any electroconductive substrate especially metal substrates such as steel, zinc, aluminum, copper, magnesium or the like can be coated with the electrodepositable composition of the present invention.
  • Steel substrates are preferred because the composition provides significant corrosion protection to these substrates.
  • the composition of the present invention may be applied to steel substrates which have not been given a chrome rinse and still provides excellent corrosion resistance.
  • the coating is heated to cure the deposited composition.
  • the heating or curing operation is usually carried out at a temperature in the range of from 120°C to 250°C, preferably from 120°C to 190°C for a period of time ranging from 10 to 60 minutes.
  • the thickness of the resultant film is usually from about 10 to 50 microns.
  • composition can be applied by means other than electrodeposition including brushing, dipping, flow coating, spraying and the like, but it is most often applied by electrodeposition.
  • Example I shows the formation of the epoxy amine adduct with the bis-ketimine of the present invention and Example II shows the formation of a coating composition as the electrodeposition bath with the epoxy amine adduct of Example I.
  • Comparison Examples A through C show the formation of the bis-ketimine with MIBK, the formation of the epoxy-amine adduct from such a bis-ketimine, and the formation of a coating composition with such an epoxy-amine adduct and a capped polyisocyanate as an electrocoat bath.
  • the yield of the bis- ketimine was determined by GC to be 27.39% in DIPK representing a 98% yield.
  • the solids were adjusted as needed by distilling off the excess DIPK to 70% .
  • Pure bis-ketimine (98% grade) was obtained by distilling off the excess DIPK and subsequently subjecting the crude bis-ketimine to reduced pressure (0.3 mm Hg; 40 Newton/meter ) distillation giving a clear yellow oil (boiling point of 160°C, 0.3 mm Hg).
  • This example describes the reaction between phenyl glycidyl ether (epoxy material) with DETA/DIPK bis-Ketimine in the formation of non-gelled amine group-containing resin as a function of molecular weight build and time.
  • DETA/MIBK bis-Ketimine as a function of molecular weight build and time. It shows that this bis-ketimine is more reactive with epoxy groups than the DIPK version (see Table 1, infra).
  • Example I The procedure described above for Example I was followed with the DETA/MIBK bis-ketimine of Comparative Example A in place of DETA/DIPK bis- ketimine of Illustrative Example 1 and the results are summarized in Table 1 infra.
  • Epoxy equivalent weight measured by titration method with tetrabutylammonium iodide and perchloric acid The units are milliequivalents per gram.
  • the data reported in Table 1 indicate the relative molecular weight build for DETA/DIPK bis-ketimine of Illustrative Example 1 and DETA/MIBK bis-ketimine of Comparative Example A on reaction with epoxy materials.
  • the molecular weight build for epoxy materials aminated with DETA/MIBK bis-ketimine as in Comparative Example B is much greater than that for epoxy materials aminated with DETA/DIPK bis-ketimine as in Example I.
  • COMPARATIVE EXAMPLE C This example describes: a) the preparation of a cationic electrodeposition bath containing a main vehicle (i.e., a cationic resin containing a diketimine derived from diethylene triamine and methyl isobutyl ketone (MIBK) of Comparative Example A and a capped polyisocyanate curing agent used in a lead-free electrocoat, and b) subsequent electrodeposition on substrates.
  • a main vehicle i.e., a cationic resin containing a diketimine derived from diethylene triamine and methyl isobutyl ketone (MIBK) of Comparative Example A and a capped polyisocyanate curing agent used in a lead-free electrocoat
  • a main vehicle was prepared from the following ingredients:
  • DMPA Dimethylolpropionic acid
  • a polyisocyanate curing agent was prepared from the following ingredients: Continuation of Footnote 2
  • MIBK Methyl isobutyl ketone
  • Polymeric isocyanate available from Dow Chemical Company as PAPI 2940 isocyanate available from Dow Chemical Company as PAPI 2940.
  • the polyisocyanate and MIBK were charged to a reaction flask under a nitrogen atmosphere.
  • the reaction was heated to 45°C and butyl CARBITOL was fed for 2.5 to 3.0 hours adjusting the temperature to 55 °C to 60°C. After the addition was complete, the temperature was adjusted to 65°C and held until the isocyanate equivalent weight of the reaction mixture was 615.
  • the isocyanate equivalent weight can be determined by any known method (for example, using the standard titration method of American Society of Testing Materials (ASTM) 309-82, which is inco ⁇ orated herein by reference or titrametrically using butylamine, first reacting the isocyanate with butylamine and then back-titrating the residual butylamine with an acid. The resultant mixmre was cooled and poured.
  • MIBK methyl isobutyl ketone
  • reaction vessel was charged with EPON 880, DMPA and Butyl Carbitol Formal. This mixture was heated to 50°C under a nitrogen blanket. To this, ETPPI was added followed by butyl CARBITOL and the resulting mixmre was heated to 125°C. The reaction was held at this temperature until the acid value was less than 1 (found 0.3741 as determined by any method known to those skilled in the art, for example by titration with an aqueous sodium hydroxide solution in acetone solution).
  • epoxy equivalent (EE) and viscosity were determined (417.3 and V respectively), (where the EE was determined as in Example I and the viscosity can be determined by any method known to those skilled in the are, for example by Gardner-Holt bubble viscometry).
  • MIBK which cooled the reaction to 75 °C to 80°C.
  • the polyisocyanate curing agent was added over 1 to 1.5 hours and the reaction held for negligible NCO (as determined by infrared spectrophotometry with a Perkin and Elmer spectrophotometer) .
  • Bisphenol A-ethylene oxide was added to the mixture and the mixture was heated to 90°C.
  • the resin mixmre (2174.6 grams "g") was dispersed in aqueous medium by adding it to a mixture of 37.7 g sulfamic acid and 1212.3 g deionized water. The dispersion was further thinned with 341.9 g deionized water, 739.2 g deionized water, and 504.0 g deionized water in stages and vacuum stripping was conducted to remove organic solvent to yield a dispersion having a solids content of 44 18 percent.
  • a pigment paste was prepared from the following ingredients. Ingredients Weight (grams) Resin Solids (grams) Resin Solids (grams)
  • a catiomc electrodeposition bath was prepared from the following ingredients:
  • An adduct generally in accordance with U.S. Patent 4.423.166 (as in Example G and the subsequent examples) was prepared from a Bisphenol A epichlorohydrin- type epoxy resm having an epoxy equivalent weight of 500, and a polyoxyalkylene- poly amine (JEFF AMINE D-2000 from Texaco Chemical Co.).
  • 10 A cationic microgei prepared as generally described in Examples A and B of U.S. Patent 5,096,556 with the exception that acetic acid instead of lactic acid was used to disperse the soap of Example A, ethylene glycol butyl ether instead of MIBK was used as a solvent in the soap of Example A, and EPON 880 solution was added after stripping rather than before in Example B.
  • the final electrocoat pamt which had a pH of 6.26 and a conductivity of 1392 micro mhos (1.39 x 10 "6 Siemens ).
  • This electrocoat paint was electrodeposited on several sets of two zinc phosphate pretreated cold rolled steel panels which are commercially available. One is available as Bonder ⁇ te ® 952 NO Parcolene ® zinc phosphated (Zn/Ni/Mn) cold rolled steel. The other panel is commercially available as CHEMFOS 168 NO CHEMSEAL 20. and it is a zinc phosphated (Zn Ni) cold rolled steel. Both commercially available steels are with no final rinse other than deionized water.
  • the electrocoating of the panels was by immersion m and electrocoaung by the pamt at 90 volts for 2 mmutes at various bath temperatures as shown below in Table 2. After rinsing with deionized water and air drying, the sets of panels were baked for 30 mmutes at 340°F (171 °C). The panels were subjected - 26 -
  • This example describes the preparation of a cationic electrodeposition bath containing a mam vehicle (i.e., a canonic resin as in Example I containing a diketimine derived from diethylene triamine (DETA) and diisopropyl ketone (DIPK) as in Illustrative Example 1 and a cappe ⁇ ooiyisocyanate curing agent) used m the lead-free electrocoat and suDsequent electrodeposition on substrates.
  • a mam vehicle i.e., a canonic resin as in Example I containing a diketimine derived from diethylene triamine (DETA) and diisopropyl ketone (DIPK) as in Illustrative Example 1 and a cappe ⁇ ooiyisocyanate curing agent
  • DIPK diketimine as in Illustrative Example 1 was used at 40 % solids instead of the MIBK diketimine as Comparative Example A.
  • the final pamt which had a pH of 6.29 and a conductivity of 1356 micromhos was electrodeposited on two substrates (B952 NO P95 and C168 NO
  • Film build was measured with an electromc film thickness meter, i.e Permascope ES manufactured by Twin City Manufacturing Co ⁇ .
  • the film build on the coated substrate is more controlled than the coating from the MIBK ketimine as shown m Table 2.
  • Tables 2 and 3 show that over a 75 °F (24°C) temperamre change for the B952 NO P95 panel the film build in Table 3 was slower than the film build shown in Table 2. Also, Table 3 shows the film build is less temperamre sensitive since higher temperamres give less film build when compared to the lower temperamres of Table 2 which result m higher film build.

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Abstract

L'invention concerne une composition de revêtement durcissable qui comporte: (A) une résine contenant des groupes amines durcissables non gélifiés, où au moins une partie des groupes amines sont des groupes amines primaires et où l'on forme la résine contenant les groupes amines en faisant réagir a) un matériau contenant des groupes époxy; et b) un dérivé amine; et (B) un agent de durcissement constitué de polyisocyanate coiffé. Dans le composant (A), le dérivé amine possède au moins un groupe bloqué sous la forme d'un groupe cétimine par réaction du groupe amine primaire avec une cétone dans laquelle les carbones fixés sur le carbone du carbonyle de la cétone sont des carbones secondaires. L'invention concerne une composition aqueuse de la résine contenant des groupes amines obtenue par neutralisation au moins partielle de ladite résine par un acide. Elle concerne également ladite composition de revêtement sous forme de composition pouvant être obtenue par électrodéposition. Elle concerne enfin la résine contenant des groupes amines durcissable non gélifiée, destinée à des compositions de revêtement.
PCT/US1996/019793 1995-12-21 1996-12-17 Compositions de revetement contenant des resines qui comportent des groupes amines, et resines dudit type WO1997023537A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU716004B2 (en) * 1995-07-10 2000-02-17 Alcatel N.V. Video server
CN114682299A (zh) * 2022-04-02 2022-07-01 湖北大学 一种聚合物纳米颗粒负载酸碱协同催化剂及其制备方法与应用

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3984299A (en) * 1970-06-19 1976-10-05 Ppg Industries, Inc. Process for electrodepositing cationic compositions
US4017438A (en) * 1974-12-16 1977-04-12 Ppg Industries, Inc. Ketimine-blocked primary amine group-containing cationic electrodepositable resins
WO1982000471A1 (fr) * 1980-08-04 1982-02-18 Ppg Industries Inc Compositions de resines autopolymerisables utiles dans des applications de revetement
EP0651035A2 (fr) * 1993-11-02 1995-05-03 Nippon Paint Co., Ltd. Composition d'électrodéposition cationique
US5472998A (en) * 1994-09-16 1995-12-05 E. I. Du Pont De Nemours And Company Polymeric additive for cathodic electrocoating compositions for improved throw power

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3984299A (en) * 1970-06-19 1976-10-05 Ppg Industries, Inc. Process for electrodepositing cationic compositions
US4017438A (en) * 1974-12-16 1977-04-12 Ppg Industries, Inc. Ketimine-blocked primary amine group-containing cationic electrodepositable resins
WO1982000471A1 (fr) * 1980-08-04 1982-02-18 Ppg Industries Inc Compositions de resines autopolymerisables utiles dans des applications de revetement
EP0651035A2 (fr) * 1993-11-02 1995-05-03 Nippon Paint Co., Ltd. Composition d'électrodéposition cationique
US5472998A (en) * 1994-09-16 1995-12-05 E. I. Du Pont De Nemours And Company Polymeric additive for cathodic electrocoating compositions for improved throw power

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU716004B2 (en) * 1995-07-10 2000-02-17 Alcatel N.V. Video server
CN114682299A (zh) * 2022-04-02 2022-07-01 湖北大学 一种聚合物纳米颗粒负载酸碱协同催化剂及其制备方法与应用
CN114682299B (zh) * 2022-04-02 2023-06-20 湖北大学 一种聚合物纳米颗粒负载酸碱协同催化剂及其制备方法与应用

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