WO1999063016A1

WO1999063016A1 - Zero-voc two-component epoxy coating system

Info

Publication number: WO1999063016A1
Application number: PCT/US1999/010487
Authority: WO
Inventors: Richard E. Hart
Original assignee: Hart Polymers, Inc.
Priority date: 1998-05-29
Filing date: 1999-06-01
Publication date: 1999-12-09
Also published as: AU4542399A

Abstract

A novel low and zero-VOC two-component epoxy coating system provides excellent chemical resistance, appearance, and adhesion. Conventional 100 percent solids liquid epoxy resins can be used for the epoxy component. These epoxy components are cured with one or more novel aliphatic amine hydrogen curative complexes used to formulate the second component and provide crosslinking. In addition, novel epoxy adducts can be used. No organic solvent is needed to achieve excellent combinations of properties.

Description

ZERO-VOC TWO-COMPONENT EPOXY COATING SYSTEM

FIELD OF THE PRESENT INVENTION The present invention relates generally to compositions and methods useful for waterborne epoxy coatings, and particularly, to a low- and zero-VOC two-component epoxy coating system which provides chemical resistance and high gloss.

BACKGROUND TO THE PRESENT INVENTION Environmental legislation affecting the coating industry includes the 1990 amendments to the Clean Air Act in the United States and similar legislation in other industrialized countries (see, for example, Chemical & Engineering News , October 27, 1997, pgs. 34-54) . State regulation has also become significant. Such regulation has helped create in recent decades a very large market need for better coatings which are based substantially, or preferably exclusively, on aqueous carrier media rather than organic solvents. In particular, minimal amounts of "hazardous air pollutants" (HAP) should be present, and the VOC ("volatile organic content" or "volatile organic compounds") should be minimized or, preferably, made zero. In addition to its environmental benefit, low- and zero-VOC also can be attractive because it generally provides low odor and easy clean-up.

Despite attempts by industry over the decades to meet this market need, however, achieving both low-VOC and high performance in a cost-effective manner has proven to be a formidable technical challenge. This challenge is magnified for zero-VOC coatings. For example, chemical resistance may be inadequate. The addition of so-called coalescing or auxiliary solvents ( "cosolvents") can improve performance in some cases but only at the expense of low- VOC. Also, low-VOC generally raises the coating cost and requires the expensive synthesis and development of new polymers. Thus, che above-noted Chemical and Engineering News article concludes: although water-reducible coatings can lower a formula's VOC profile compared to a similar solvent-based formula, a water-reducible coating with few exceptions cannot be formulated without VOC-containing ingredients.

See page 35 (emphasis added) .

Low-VOC coatings are also discussed in Water-Borne Coatings,

The Environmentally-Friendly Alternative, by Klaus Doren et al . (Hansler Publishers, 1994) , the complete disclosure of which is hereby incorporated by reference. This reference also teaches on pages 53 and 55 that auxiliary organic solvents can be difficult to eliminate. Technical quality issues which may be sacrificed with low-VOC include, for example, pigment wetting, drying, gloss, and corrosion protection. In addition, low-VOC coatings are also discussed in Film Formation in Waterborne Coatings, ACS Symposium Series 648, Eds. T. Provder et al . (American Chemical Society, 1996) , the complete disclosure of which is hereby incorporated by reference. In particular, Chapter 24 of this reference discusses the difficulty of achieving uniform film morphology in two- component epoxy systems. The proposed improved formulation in this reference still contains glycol ether coalescing solvent and has a calculated VOC of 144 g/L. Hence, zero-VOC is not attained with this system.

U.S. Patent Nos. 5,352,733 and 5,508,340 (inventor: Richard E.

Hart) further discusses the need for zero-VOC coatings. These patents disclose water-based two-component aliphatic polyurethane coatings. However, no guidance is provided for formulating epoxy systems, the subject of this application.

Conventional epoxy resins are generally discussed in, for example, Handbook of Epoxy Resins by H. Lee and K. Neville (McGraw- Hill, 1967 with 1982 reissue) . Chapter 24 of this reference, in particular, discusses epoxy-resin solution coatings.

Illustrating low-VOC epoxy prior art, U.S. Patent No. 4,564,648 (Du

Pont) describes a process in which epoxy resin is emulsified in xylene before let-down in water. This example illustrates how the art generally depends on the time-consuming, costly, and environmentally unacceptable process of reacting resin in the presence of organic solvent before water le -down. Because of these difficulties and a general lack of cost-performance, industry has generally resisted going to zero-VOC. Other patents include, for example, U.S. Patent Nos. 3,427,266; 3,707,526; 4,066,591;

4,127,543; 4,220,568; 4,278,579; 4,331,574; 4,608,413; 4,876,302;

4,945,128; 5,075,370; 5,227,198; 5,331,039; 5,350,784; 5,599,855; and 5,670,599.

In particular, high-performance, low- and zero-VOC two- component epoxy coatings are needed because this versatile coating system is so widely used in industry (see, for example, U.S. Patent Nos. 5,350,784 and 5,599,855 to Air Products and Chemicals). Although solvent-based epoxy resins provide excellent toughness and chemical resistance, considerable difficulty exists in obtaining the same performance in waterborne epoxies (see, for example, Coatings World, March/April 1997, pages 68 and 73) . According to this reference (p. 68) , research has been conducted into "why waterborne epoxy-amine coatings show considerably lower chemical resistance than their solventborne counterparts . " Although the results of this research were that "incremental improvements [in chemical resistance] are possible", the researchers also concluded that "chemical resistance, even with these steps, cannot be brought to the level of solvent-based systems" and that there are "inherent limitations to the chemical resistance of waterborne eooxy systems . " Moreover, adequate pot life and sufficient cure speed generally work against each other for a given two-component epoxy formulation. Hence, epoxies are a particularly challenging problem to the formulator of high-performance low- and zero-VOC two- component coatings.

SUMMARY OF THE PRESENT INVENTION

Objects of the present invention include the development of compositions and methods for low- and zero-VOC two-component epoxy systems. Zero-VOC is the ultimate objective. Cost-performance should compete with or even exceed that of conventional solvent- based epoxy systems. The present invention provides a two-component epoxy coating prepared by curing a low- or zero-VOC mixture of two components, wherein a first component, before mixing of the components, includes a water-dispersible epoxy resin or a water-dispersible reaction product of epoxy resin and an epoxy adduct, wherein a second component, before mixing of the components, is a water- dispersible curative for the epoxy component and includes a mixture of ingredients including at least one first amine compound which is a diamine having two primary amine groups, at least one second amine compound which is an alkanolamine compound, and at least one third amine compound which is a primary or a secondary amine, wherein the three amine compounds are different from each other, wherein the amount of the ^"first amine compound is greater than the amount of either the second or third amine compound. The present invention also provides a multi-component epoxy coating prepared by drying and curing a low- or zero-VOC precursor composition, the precursor composition being a mixture of at least two components, wherein at least one component for the coating, before mixing of the components, is an epoxy component including an epoxy resin, and the epoxy component is formulated for dispersability of the epoxy resin in water, wherein at least one other component for the coating, before mixing of the components, is a curative for the epoxy component and is formulated for dispersability in water, the curative being prepared from a first aliphatic amine hydrogen curative complex which is a mixture of ingredients including, before mixing, at least one primary amine ingredient and at least one alkanolamine ingredient, wherein the amounts of the curative and the first aliphatic amine hydrogen curative complex are sufficient so that the dried and cured epoxy coating has an MEK double rub value of at least about 500. The present invention includes cured compositions, compositions used to prepare curable and cured compositions, coating kits, articles of manufacture comprising the cured compositions, methods of making compositions, methods of formulating compositions, and methods of using uncured and cured compositions.

Advantages of the present two-component epoxy system are numerous and include environmental friendliness, good chemical resistance, good adhesion, good pot life, fast cure speed, excellent appearance and gloss, high-solids, easy-clean-up, low odor, and excellent combinations of these and other properties. Moreover, the coatings are relatively easy to formulate. Finally, they are cost-effective. Surprisingly, all of this can be achieved with zero-VOC.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

DEFINITIONS

A "coating kit" means a collection of items which can be used in combination in a coating or paint. The kit can include, for example, separately packaged compositions such as a resin composition, a crosslinker composition for the resin, a composition used to formulate the crosslinker composition, and/or a composition used to formulate the resin composition. Other kit items can be included such as, for example, instructions, mixing aids, and/or additives. The separately packaged compositions of the kit then can be mixed by a user of the coating kit. There is no particular limit to the number of individual compositions or accessories which can be included in the kit, although two-component kits are preferred.

"Consisting essentially of" means that VOC in the pre-dried precursor coating composition is low compared to conventional organic solvent-based coating compositions. A basic and novel feature of this invention is that the coatings are low-VOC and preferably zero-VOC. There is no absolute cut-off to the relatively small amount of VOC which can be included in a low-VOC coating. A suitable cut-off may vary depending on, for example, the particular application, the scale of operation, or ever- changing environmental regulations in different countries. For example, the U.S. Environmental Protection Agency has proposed VOC limits (g/L) for 1996 and 2000 for different coating types (for example, see Coatings World, March/April 1997, pg. 51) . These limits generally have been in the range of about 100-700 g/L depending on the coating type and year. As technology develops, these limits are expected to be further reduced. Hence, the VOC immediately after mixing of the components can be less than about 500 g/L, and preferably less than about 100 g/L, and more preferably, less than about 50 g/L, and more preferably, less than about 10 g/L. VOC can be calculated from the knowledge of the coating formulation ingredients. Volatile organic compounds to be excluded are well-known in the art and include common organic solvents such as, for example, hydrocarbon and aromatic solvents including toluene and xylenes; ketone solvents including methyl ethyl ketone and methylamylketone; esters including ethyl acetate and butyl acetate, and ethers including THF. Preferably, VOC is essentially zero, and no solvents are added to any coating component during formulation, even if later removed. "Low-VOC" means that the calculated VOC of a coating precursor composition, which dries and cures to form a coating, is formulated to be less than about 500 g/L. Preferably, VOC is less than about 100 g/L, and more preferably, less than about 50 g/L, and even more preferably, less than about 10 g/L. "Zero-VOC" means that the calculated VOC of a precursor coating composition is less than about 1 g/L. Preferably, however, VOC is less than about 0.1 g/L and is substantially zero for zero-VOC. Moreover, organic solvents are preferably not used at all in formulation of the coating: solvent should not be used during formulation and then removed before final formulation.

"MEK double rub" values are obtained by dampening a cotton cloth with methyl ethyl ketone and firmly rubbing the saturated cloth over the coated substrate (one up and down rub is a double rub) . The cloth is occasionally resaturated with methyl ethyl ketone when required. The thickness of the coating is about 2-3 mil (dry) . Aluminum substrates are generally used because it is relatively difficult to obtain good adherence and high MEK rub values with this substrate compared to, for example, steel substrates. The reported number is the number of double rubs required to just break through the coating to the substrate (for MEK rub tests, see for example U.S. Patent Nos. 5,508,340 and 4,331,574) .

A "precursor composition" is a reactive coating composition which will spontaneously cure and crosslink to form a cured crosslinked coating upon drying under ambient conditions. For multi-component coatings, reaction generally begins immediately or very soon after mixing individual components. Reaction heads to completion as the carrier medium evaporates and the coating hardens. The precursor composition may be subject to an induction period before application. An "aliphatic amine hydrogen curative complex" (or "AAHCC") is a composition which is a mixture of aliphatic amines and optional other components specifically formulated to help cure a target reactive polymer in a multi-component low- or zero-VOC coating system. For example, an "epoxy AAHCC" means the target reactive polymer is epoxy. In general, a single aliphatic amine cannot provide the desired balance of properties to the epoxy and obtain the combinations of properties. Therefore, aliphatic amine mixtures are used. More than one AAHCC composition can be used to formulate the coating. In this case, there is a "first AAHCC", a "second AAHCC" or a "third AAHCC" as required. Preferably, when more than one AAHCC is used, each AAHCC is prepared separately before they are ultimately mixed together to formulate a coating component. The amines of the AAHCC are generally aliphatic in nature rather than aromatic amines and generally have alkyl and/or alkanol groups bonded to the amine nitrogen (s) . A mixture of primary, secondary, and/or tertiary amines can be used effectively to achieve the required balance of properties for a particular application. Also, a mixture of single-, di-, tri-, tetra-, and/or poly-amine compounds can be used. It is believed that the different reactivity of the amine hydrogens provide a subtle balance of cure speed, pot life, appearance, and other properties which cannot be achieved by conventional epoxy curing agents . A preferred AAHCC can be prepared which is a mixture of ingredients in the form of a clear liquid. Preferably, this clear type of AAHCC is formulated without a polymer. Another preferred AAHCC can be a mixture of ingredients in the form of a milk-like dispersion and can be formulated with a polymer present such as, for example, a polyurethane, an acrylic, a poly (vinyl acetate) , or a styrene- butadiene copolymer.

"Epoxy adduct" means a composition which can improve the dispersability of epoxy resin in water. The adduct preferably at least partially reacts with, or interacts strongly with or complexes with, the epoxy resin.

"Chemical resistance" means that the cured coating is generally stable to convention chemical resistance tests such as rubbing the coating with methylethylketone (e.g., survives 500 rubs) , immersion in jet aircraft hydraulic fluid, and aqueous acid and base testing.

"100 percent solids liquid epoxy resin" means that no organic solvents are present in the epoxy resin, but the epoxy resin is sufficiently low in molecular weight and viscosity to be liquid and flows at ambient (see, for example, U.S. Patent No. 5,599,855 and

4,331,574) .

"Pot life" means the working time available after mixing the coating components until viscosity becomes too high for application or other undesirable changes to the composition occur such as loss of compatibility.

"Formulated" means that coating and paint ingredients and compositions are selected, reacted, and/or used in amounts to achieve a desired property such as, for example, dispersability, gloss, pot life, cure speed, or chemical resistance. During formulation, for example, ingredients can be mixed with other ingredients to form compositions, and compositions can be mixed with other compositions or other ingredients to form a final composition such as, for example, a crosslinking component.

"Water-dispersible" means that an ingredient or composition can be mixed into an aqueous system without settling out, formation of gel, coagulation, precipitation, or other types of generally large-scale inhomogeneity. Rather, the ingredients or composition remain suspended in the aqueous media so that a commercially viable coating is possible. EPOXY RESIN COMPONENT

In a two-component system, the epoxy component includes at least one epoxy pre-polymer resin which reacts with a crosslinker component to harden the resin. The epoxy resin component functions to provide a polymeric or oligomeric base to the coating or paint which is then crosslinked to form a strong network structure. The epoxy is selected to provide toughness, flexibility, adhesion, and chemical resistance at a suitable level of cost-performance. Epoxy resins are described in, for example, U.S. Patent Nos. 4,331,574; 5,350,784; 5,599,855; and 5,527,839 which are hereby incorporated by reference. Epoxy resins are also extensively discussed in the aforementioned Handbook of EΌOXV Resins, Chapters 1-4, which are incorporated by reference.

Heretofore, low-VOC epoxy coatings generally required liquid solvents to achieve performance. Zero-VOC epoxies in particular suffer from lack of performance and/or high cost. In this invention, however, 100 percent solid liquid epoxy resins surprisingly can be used without organic solvent to achieve high performance at good cost . The epoxy resin can have, for example, an epoxide equivalent weight (EEW) of about 80 to about 1,000, and preferably, of about

100 to about 500, and more preferably, about 110 to about 300, and even more preferably, about 140 to about 240. Lower viscosity liquid type epoxies are preferred particularly for a zero-VOC system.

Conventional epoxy resins can be used which, by themselves (without adduct) , are either water-reducible, partially-reducible, or not water-reducible. As discussed further below, an epoxy adduct can be used when the epoxy resin is not easily reduced in water. Epoxy resins generally can be of the following forms: liquid resin with emulsifier added; liquid resins with chemically bound emulsifiers; epoxy resins with reactive diluent; and emulsifier- containing dispersions. Preferably, the epoxy resin is emulsifier- free as in general the emulsifier lowers performance. Aliphatic, cycloaliphatic, aromatic, and mixed

(cyclo) aliphatic-aromatic epoxy resins can be used. Bisphenol- based epoxy resins are preferred, and more preferred epoxy resins include those based on epichlorohydrin and bisphenol A. Other hydroxyl-containing compounds can be used to prepare the epoxy resin including resorcinol, hydroquinone, glycols, and glycerols. Epoxy resins can be used which are esterified with fatty acids to provide epoxy resin esters. Mixtures of epoxy resin can be used.

Representative examples of commercial epoxy resins include: PPI 727-0100 Liquid Epoxy Resin (Peninsula Polymers) having an epoxide equivalent weight of about 188; Dow Series liquid epoxy resins (Dow) of the bisphenol A type (D.E.R.) including DER 317,

DER 331, DER 332, DER 337, DER 364, and DER 383; and Shell

Chemical's Epon series of appropriate EEW including Epon No. 828.

Further information provided by the supplier for the PPI 727- 0100 Liquid Epoxy Resin includes: a standard grade of diglycidyl ether of bisphenol A; no diluents or modifiers; viscosity (cps © 25 ^*C) of 13,500; color (G-H) < 1; lbs. /gal 9.70; epoxide E.W. of 188; and hydrolyzable chlorine < 1,000.

Preferably, the epoxy resin is used in conjunction with the epoxy adduct composition as described below.

EPOXY ADDUCT

The epoxy resin optionally can be used in conjunction with an epoxy adduct composition. Use of the epoxy adduct provides the advantage that the epoxy resin can be dispersed in water and remain dispersed under a broader range of conditions without the presence of organic cosolvents. Also, the epoxy adduct can improve the drying characteristics. In some cases, the epoxy adduct composition may react with, for example, isocyanate functionality to improve crosslinking and coating compatibility. Also, the adduct can improve flexibility of the cured coating. The epoxy adduct composition can be dispersed in water to provide a clear thick solution. This solution remains clear afcer the epoxy resin is mixed with the epoxy adduct-water dispersion. This is surprising in that the preferred epoxy adducts are not polyamines or polymeric amines and do not have extensive concentration of hydrophilic amine groups. Rather, polar acid groups such as carboxylic acid groups are preferably present in the epoxy adduct which are believed to provide the polarity needed for excellent dispersion.

Heating of the epoxy adduct mixed with the epoxy resin can speed-up the mixing although room-temperature mixing of adduct and epoxy can also be used. Some reaction is believed to occur between the epoxy resin and the adduct upon mixing, although it is believed that dispersion may be possible even without a reaction.

The amount of the epoxy adduct composition relative to the mixture of epoxy resin and epoxy adduct composition can be at least about 3% by wt . , and preferably, at least about 5% by wt . , and more preferably, at least about 8% by wt . The amount can be less than about 15% by wt . , and preferably, less than about 12% by wt .

The epoxy adduct composition can be oligomeric or polymeric in nature and is prepared by condensation polymerization methods. The resulting product preferably is acid functional, and preferably carboxylic acid functional. The resulting product also is preferably hydroxyl functional. The condensation can be carried out in the presence of pre-formed polymer ingredients or with use of low molecular weight monomers used in polyester synthesis. For oligomeric or polymeric polyester ingredients, the condensation synthesis can result in transesterification reactions during condensation synthesis of the adduct. An acid-functional polyescer polyol epoxy adduct composition can be synthesized under conditions which keep molecular weight lower which generally improves water dispersability.

The epoxy adduct composition can be based on, for example, a polyester or a polyether backbone, and preferably a polyester backbone. Combinations of different types of polyester backbone can be used. Conventional ingredients used to synthesize polyesters can be used including conventional polyfunctional hydroxyl, acid, hydroxyacid, and acid anhydride compounds.

Polyamine, polymeric amine, or polyamide is not generally used to form the epoxy adduct, and in many embodiments, these types of adduct may be detrimental . Preferred diols for adduct synthesis include C₅-Cι₂ cyclic aliphatic compounds such as, for example, cyclohexanedimethanol . In addition, small amounts of polyfunctional C₃-C₈ hydroxy compounds can be used such as, for example, 2-methyl-2-hydroxymethyl-l,3- propanediol to control branching which can affect dispersability. Preferred diacids include C₃-C₁₂ cycloaliphatic diacids such as, for example, 1,4-cyclohexanedicarboxylic acid.

In addition, anhydride compounds, and preferably C₆-C₁₂ aromatic anhydride compounds, can be used for adduct synthesis. Preferred examples include phthalic anhydride and trimellitic anhydride. Moreover, acid functional polyols, preferably diols, can also be used in adduct synthesis to provide further acid functionality. Examples include alpha, alpha-dimethylol alkanoic acids represented by the structure:

R-C(CH₂-OH)₂(COOH) wherein R is an alkyl group of 1 to 8 carbon atoms, as disclosed in U.S. Patent No. 5,352,733, which is incorporated by reference. The carboxylic acid group is preferably a hindered tertiary carboxylic acid group. A preferred acid functional diol is 2,2- dimethylolproprionic acid (DMPA, Perstorp Specialty Chemicals) . Preformed oligomeric and polymeric polyester components which can be used in adduct synthesis include saturated polyesters having hydroxyl end groups such as ethylene propylene adipate polyol and neopentyl glycol adipate polyol oligomers and polymers. Examples of polyester diols include: RUCOFLEX saturated polyester diol S- 1017 (Ruco Polymer Corp., available as S-1017-55 and S-1017-110) which is an ethylene propylene adipate polyol; RUCOFLEX saturated polyester diol S-107 (Ruco Polymer Corp., available as S-107-55, S- 107-110, and S-107-210) which is a neopentyl adipate polyol. Nominal molecular weights of these commercial polyesters are about 1,000 to about 5,000. The materials can range from waxy solids to slushy liquids. Hydroxyl numbers can range from about 40 to about 250. Acid number should be less than 1. Brookfield viscosity (60^*C/cps) is generally less than about 3,000.

In addition, the epoxy adduct composition is preferably prepared with use of multifunctional compounds having both hydroxy and allyl functional groups such as, for example, trimethylolpropane monoallyl ether which provide pendant unsaturation. Typically, the amount of the compound used to introduce pendant unsaturation is between about 2 and about 15, and preferably, between about 5 and about 10, parts by weight relative to 100 parts by weight of the total solids content of epoxy adduct composition.

Conventional synthetic methods including melt condensation polymerization methods can be used to prepare the acid functional epoxy adduct. Preferably, water and organic solvent are not present during synthesis. When condensation synthesis is complete, the resultant polymer epoxy adduct composition preferably has a viscosity at 72 'F of about 2,000 to about 4,000 CPS . The acid number preferably is between about 10 and about 100, and more preferably, between about 30 and about 70, and more preferably, between about 40 and about 50. The hydroxyl number is preferably between about 10 and about 120, and more preferably, between about 20 and about 80, and more preferably, between about 45 and about 65. The acid number of the final epoxy adduct can be controlled to provide proper dispersability and mixing with other components such as, for example, pigments to achieve the desired performance without use of organic solvents.

In a preferred embodiment, the epoxy adduct is a reaction product of ingredients which include a cycloalkane diol compound, a compound having both anhydride and carboxylic acid functionality, a cycloalkane dicarboxylic acid compound, a polyester diol, and a compound providing both a pendant allyl group and at least two functionalities to bind the compound covalently with the adduct. A compound which provides branching such as a trifunctional compound can also be used as required. Also, a difunctional aromatic compound can be used as required. In a particularly preferred embodiment for epoxy adduct synthesis, the reaction components include: neopentyl glycol adipate saturated polyester diol (about 5 to about 20 parts by weight); 1, 4-cyclohexanedimethanol, 90% (about 20 to about 40 parts by weight) ; 2-methyl-2-hydroxymethyl-l, 3-propanediol (about 0.1 to about 2 parts by weight) ; trimellitic anhydride (about 10 to about 30 parts by weight) ,- phthalic anhydride (about 0.5 to about 5 parts by weight) ; dimethylolprpprionic acid (about 3 to about 20 parts by weight) ; butyl stannoic acid as a condensation catalyst (in an effective amount such as, for example, about 0.01 to about 0.5 parts by weight); 1, 4-cyclohexanedicarboxylic acid (about 10 to about 30 parts by weight) ; and trimethylolpropane monoallyl ether

(about 5 to about 10 parts by weight) ; wherein the sum of the component parts is 100.

Condensation of the ingredients initially is preferably carried out as a melt polymerization in the substantial absence of the compound providing pendant unsaturation such as trimethylolpropane monoallyl ether. This allyl compound then can be added after melt polymerization is substantially completed.

During synthesis, all components used to prepare the epoxy adduct are preferably substantially free of water and organic solvents. Water formed by condensation during melt polymerization is preferably substantially removed before further formulation of the adduct .

After synthesis, the epoxy adduct composition can be packaged separately or packaged with the epoxy resin and/or water for further use in formulating a two-component coating. Generally, the adduct can be pre-mixed with the epoxy resin if desired. In general, coagulation and gelation can occur for epoxy resins in water without use of the epoxy adduct .

Unlike the epoxy adduct of U.S. Patent No. 5,350,784, the epoxy adduct of this invention does not require use of formaldehyde. Also, aziridines are not used in formulating the epoxies of this invention.

CROSSLINKER COMPONENT

The crosslinking component which reacts with and crosslinks the epoxy component can be a complex mixture of ingredients and compositions. Conventional coating and paint formulation ingredients can be used as desired together with the compositions of this invention.

The crosslinker preferably is an aqueous solution or dispersion which contains water in amounts of about 15% to about 80% parts by weight, and preferably at about 20% to about 70% parts by weight. The aqueous component also can contain acrylic resin, polyurethane resin, vinyl acetate resin, vinyl acrylic resin, butadiene-styrene resins and other polymeric resins, in amounts of about 10% to about 60% parts by weight, and preferably at about 15% to about 50% parts by weight.

The crosslinking component also can be prepared with use of at least one, and optionally, at least two aliphatic amine hydrogen curative complexes, which are described further below, in amounts of about 3% to about 30% parts by weight, and preferably, about 5% to about 25% parts by weight. These aliphatic amine hydrogen curative complexes generally are prepared as separate compositions before final formulation into the crosslinker.

The crosslinking component can also contain, for example, rutile titanium dioxide pigment and other known inorganic and organic fillers and pigments typically at about 5% to about 50%, and preferably, at about 10% to about 40% parts by weight._.

Finally, the aqueous component can also contain additives such as defoamers, wetting aids, thickeners, and flow aids at about 0.5% to about 15%, and preferably about 2% to about 12% parts by weight. In particular, the following epoxy aliphatic amine hydrogen curative complexes are believed to help provide the high performance in this low- and zero-VOC system. Standard epoxy curatives, including water-reducible curatives, do not generally provide this performance under the constraints of low- or zero-VOC. Rather, the conventional low- and zero-VOC coatings will suffer from, among other things, lack of hardness development during air dry and poor appearance .

ALIPHATIC AMINE HYDROGEN CURATIVE COMPLEXES

The epoxy component can be combined and packaged in the coating kit with a separate curing component which is prepared with use of one or more aliphatic amine hydrogen curative complexes

(AAHCC) . At least two distinctly different types of AAHCC, which are described further below, can be formulated: the first type is generally polymer-free, whereas the second type generally includes polymer and is a polymer dispersion. Of particular interest for the polymer-containing AAHCC is inclusion of polyurethane into the AAHCC. The polymer-containing AAHCC can have the appearance of a milky dispersion, whereas an AAHCC which is generally free of polymer is desired to be transparent. Preferably, if more than one AAHCC complex is formulated in preparation of the crosslinking component, the multiple AAHCC compositions are mixed together before inclusion into the coating kit so that there is only one final crosslinking component for the epoxy component.

Each of the AAHCC compositions are formulated to provide the two-component epoxy system with a balance between fast cure speed and sufficient pot life. However, other properties such as ingredient compatibility and coating appearance also can be affected by the AAHCC formulation.

Amine components which can be used in the AAHCC are disclosed in, for example, U.S. Patent Nos. 5,352,733 and 5, 508, 340, although these references are directed to urethane rather than epoxy formulations. Urethane and epoxy coating systems cure by distinctly different reactions. Hence, the formulations described in these patents cannot be used directly to formulate epoxy resin. Aliphatic amine curing agents are disclosed in, for example, Chapter 7 of the aforementioned text, Handbook of EPOXV Resins, which is hereby incorporated by reference. The general types of aliphatic amines include aliphatic diamines, linear and branched aliphatic polyamines, and alicyclic polyamines . Although blends of amines are discussed at pages 7-26 through 7-30 of this reference, the different types of AAHCC of the present invention directed to low- and zero-VOC coatings are not taught or suggested. In particular, blends of three, four, or more amines are not taught or suggested. Also, blends including polymer dispersion are not taught or suggested. FIRST ALIPHATIC AMINE HYDROGEN CURATIVE COMPLEX

The first AAHCC composition has minimal amounts of polymer and is preferably essentially polymer-free. It is generally formulated to be a clear liquid rather than a milky dispersion. Oligomeric components (for example, molecular weight of less than 500, or preferably less than 400) can be used if desired to the extent that clear liquids are formed rather than polymeric dispersions. The principal function of the first AAHCC is to cure the epoxy resi rather than merely catalyze cure of the epoxy resin. Hence, sufficient functional group must be present to achieve this purpose .

The first AAHCC can be characterized by an amine hydrogen equivalent weight. As noted in the working examples below, the average equivalent weight of the AAHCC composition can be determined by dividing the total weight of reactive ingredients

(excluding any water or other volatile solvent which would be removed during drying) by the total number of equivalents of reactive ingredients (also excluding any water and volatiles) . In determining the total number of equivalents of reactive ingredients, information from the ingredient supplier can be considered in estimating the effective equivalent weight of the ingredient when used in a two-component epoxy formulation. This amine hydrogen equivalent weight can be between about 10 and about 90, and preferably, between about 20 and about 80, and more preferably, between about 30 and about 70.

The viscosity of the first AAHCC at 75 ^*F can be, for example, between about 25 and about 500 CPS, and preferably, between about 50 and about 250 CPS, and more preferably, between about 100 and about 200 CPS. Some water can be present in the first AAHCC, and if present, the amount of water can be between about 1 wt . % and about 30 wt.%, and preferably, between about 5 wt . % and about 15 wt.%. Water, however, is preferably substantially excluded, particularly if non-polar components are used in the AAHCC.

At least two different amine compounds can be used in the first AAHCC mixture. Preferably, at least three different amine compounds can be used, and more preferably, at least four different amine compounds can be used in formulating the AAHCC. These amine compounds include C₂-C₁₀ primary, secondary, and tertiary amine compounds. These amine compounds can also be hydroxyl functional and can be alkanolamine compounds. There can be one, two, three, four, or even more nitrogen atoms per molecule. Also, there can be one, two, three, or even more hydroxyl groups per molecule. Preferably, an acid functional molecule has only one acid group per molecule. High-molecular weight polymers in general, and polymeric amines in particular, are preferably not used to prepare the first AAHCC.

Examples of compounds which can be included in the AAHCC include, for example , triethanolamine , dimethylolproprionic acid, 2 - a m i no - 2 - m e t hy 1 - 1 - p r o p a n o 1 , d i e t h a n o 1 a m i n e , 2 - methylpentamethylenediamine , 1 , 3 -pentanediamin , 1 , 2 - diaminocyclohexane , monoethanolamine , dimethylaminopropylamine , ethylene diamine , dimethylethanolamine , N-methyldiethanolamine , monomethylethanolamine, 2- (2-aminoethoxy) ethanol, N,N-dimethyl-2- (2-aminoethoxy) ethanol , tetramethylbis (aminoethyl) ether, diethylene triamine, and triethylenetetraamine. Morpholine compounds can also be used such as, for example, morpholine, N-methylmorpholine, N- ethylmorpholine, N-butylmorpholine, N-methylmorpholine oxide, and DMDEE (available from Huntsman Corp.). Substituted propylamines which can be used include dimethylaminopropylamine, methoxypropylamine, and aminopropylmorpholine. Piperazine compounds can be used such as, for example, N-aminoethylpiperazine and dimethylpiperazine .

Optionally, lower molecular weight polyoxyalkyleneamine compounds can be used although for the first AAHCC the molecular weight and amount of this compound is preferably kept low enough to allow for a clear solution and avoid forming a polymeric dispersion. These compounds generally have ethylene oxide or propylene oxide repeat units with at least one amino end group. Polyoxyalkyleneamine compounds are available as the JEFFAMINE^® series from Huntsman- Corp. JEFFAMINE D-230, JEFFAMINE D-400, and JEFFAMINE T-403 are illustrative commercial examples of lower molecular weight compounds in this series.

Phenolic compounds can also be included in the AAHCC. Examples include nonylphenol and 2, 4 , 6- tris (dimethylaminomethy1) phenol . In general, nonylphenol can be more effectively used when mixed into compositions which are water- free. This helps ensure dispersal of this ingredient. Surprisingly, after mixing nonylphenol into the AAHCC composition, water can be added later in formulation, and the nonylphenol can remain dispersed. Although not fully understood, some complexation of the nonylphenol with other ingredients may occur.

Conventional and effective amounts of surfactants, wetting aids, defoamers, and other conventional coating additives can be included in the first AAHCC. Amounts can be, for example, less than 5 wt . % and preferably less than 3 wt . % .

The amounts of primary, secondary, and tertiary amines in this first AAHCC are generally balanced to provide good aqueous dispersability, good cure speed, and suitable pot life for a two- component epoxy system for a particular application. In particular, sufficient amounts of a diamine compound having two primary amino groups can be used. This compound can be C₃-C₇ and preferably is C₆. The primary amine, 2-methylpentamethylene diamine (MPMD) , can be used to provide fast cure for the epoxy. About 20% to about 60%, and preferably about 25% to about 50%, parts by weight of the solids content for the first AAHCC is MPMD. Preferably, this amine ingredient is the principal amine ingredient. A secondary amine such as the alkanolamine, diethanol amine (DEA) , can be used to help slow the cure speed and provide pot life. Preferably, combinations of ingredients such as MPMD and DEA are used to provide the suitable balance between sufficient pot-life and fast cure speed.

In one embodiment, the first AAHCC is prepared by mixing water (about 5-15 parts by weight) , triethanolamine (about 5-15 parts by weight) , dimethylolproprionic acid (about 2-6 parts by weight) , 2- amino-2-methyl-1-propanol (about 2-15 parts by weight) , diethanolamine (about 5-15 parts by weight) , 2- methylpentamethylenediamine (about 40-60 parts by weight) , monoethanolamine (about 3-10 parts by weight) , and dimethylaminopropylamine (about 1-4 parts by wt . ) , wherein the total weight of the composition is 100 parts by weight. Among these ingredients, diethanolamine and 2-methylpentamethylenediamine are generally believed to be most important to achieve suitable properties. The other ingredients can be used as required. In general, 2-amino-2-methyl-l-propanol and triethanolamine can be useful .

In general, coating appearance such as absence of fish eyes can be improved by removing water from the first AAHCC illustrated in Example 1 below (see Example 5) . Also, if water is substantially removed from the formulation, an alkylphenol compound such as nonylphenol can be added and other compounds removed to improve coating performance. Hence, a preferred composition is prepared from nonylphenol, MPMD, DEA, and other optional ingredients but without water. MPDM should be present in an amount of at least about 25 wt.%, and preferably at least 30 wt.%. More particularly, a preferred composition is prepared by mixture of the following ingredients: nonylphenol (about 4-15 parts by weigh ) ; triethanolamine (about 7-16 parts by w . ) ; 2 -amino-2 -methyl-1- propanol; 2-methylpentamethylenediamine (about 15-35 parts by weight); diethanolamine (about 7-16 parts by w . ) ; and as required additives such as surfactants, wetting agent, and defoamer (about 2-10 parts by wt . ) , wherein the total weight of the composition is 74 parts by weight.

In one alternative formulation of the crosslinker, the first AAHCC can be added to a resin dispersion such as an acrylic resin to yield a functional acrylic. This functional acrylic then can be further formulated to provide the crosslinker.

SECOND ALIPHATIC AMINE HYDROGEN CURATIVE COMPLEX

In one embodiment, the first AAHCC is used in a strategic combination with a second polymer-containing AAHCC which is formulated somewhat differently than the first AAHCC. Optionally, this polymer can be a polyurethane, and more preferably, aliphatic polyurethane. Amine and phenol components used in the first AAHCC can also be used in the second AAHCC. The function of the second AAHCC, however, primarily is to catalyze cure and crosslink. Thus, the second AAHCC is formulated and used in amounts so as to contribute fewer reactive equivalencies to the epoxy crosslinking component than the first AAHCC. The second AAHCC helps provide a suitable combination of fast cure speed and good pot-life. Moreover, by first mixing the amine curatives into a high-solids polymer dispersion, formation of particulates can be avoided and homogeneous lattices can be achieved.

After preparation, the second AAHCC generally has the appearance of a milky liquid. It is a dispersion of polymer in water together with a series of amines and optional additives. Its viscosity at 75 "F can be between about 25 and about 500 CPS, and preferably, between about 50 and about 250 CPS, and more preferably, between about 100 and about 150 CPS. Water is preferably present, and the percent free water can be between about 30 wt.% and about 80 wt.%, and preferably between about 40 wt.% and 70 wt.%. The percent solids can be at least about 30 wt.%, and preferably, at least about 40 wt.%. The acid number is preferably between about 20 and about 250, and preferably, between about 40 and about 175, and more preferably, between about 60 and about 130. The hydrogen equivalent weight can be about 50 to about 500, and preferably, between about 100 to about 400, and preferably, between about 150 and about 350. Hence, the hydrogen equivalent weight for the second AAHCC is generally much higher than for the first AAHCC.

The second AAHCC can be prepared from a polyurethane pre- polymer phase, which is prepared by reaction of hydroxyl functional polymer with a series of ingredients including one or more multifunctional aliphatic isocyanate compounds. The pre-polymer phase is further formulated with a series of formulation phases including one or more neutralization compounds; additives; water; one or more chain extending compounds; and a Lewis-base addition phase. In particular, the Lewis-base addition phase is an important aspect of this invention because it facilitates ambient air-drying. For example, when the two-component epoxy coating is dried overnight, the coating should be finger nail hard the next day. Examples of components used to prepare the initial urethane pre-polymer phase include components used to formulate a single- component polyurethane dispersion. These include one or more oligomeric diols such as, for example, hexaneadipate polyester diol, polyether diols, hydroxyl functional hydrocarbon polybutadiene diol, dimethylolproprionic acid, dibutyltin dilaurate (urethanation catalyst) , and trimethylolpropane monoallyl ether. The number average molecular weight (GPC) of the oligomer diol can be about 500 g/mol to about 3,000 g/mol, and preferably no more than about 2,000 g/mol. These ingredients are allowed to react with each other before further reaction with multifunctional isocyanate compound.

Examples of multifunctional isocyanate compounds used to prepare the prepolymer phase include cycloaliphatic isocyanate compounds such as isophorone diisocyanate (IPDI) available from Huls America as VESTANAT IPDI . This compound is preferred for light stability and weather resistance. In addition, bis (4- isocyanatocyclohexyl) methane can be used (DESMODUR W, Miles). TMXDI (META) Aliphatic Isocyanate (meta-tetramethylxylylene diisocyanate, Cytec) can also be used. Aromatic isocyanate compounds, characterized by direct bonding between the isocyanate linkage and the aromatic ring, are less preferred. They tend to react with water and also cause yellowing. After formulation of the pre-polymer phase is completed, it can be neutralized.

Examples of components in the neutralization phase include tertiary alkyl amines such as triethylamine or triethanolamine. Components in this phase help improve water dispersability. Neutralization components are also described in the incorporated U. S . Patent Nos . 5 , 352 , 733 and 5 , 508 , 340 .

Up to this point in the formulation of the second AAHCC, water is preferably avoided. However, after neutralization of the pre- polymer, water can be added including aqueous solutions of ingredients such as, for example, surfactants, wetting aids, and defoamer. After neutralization, the aliphatic urethane pre-polymer is then ready for chain extension.

Examples of components which can be in the chain extension phase include 2-methylpentamethylenediamine, ethylene diamine, diethylene triamine, and other triamines . The chain extension phase also preferably includes water. Chain extension components are also described in the incorporated U.S. Patent No. 5,352,733 and 5.508,340. At this point in formulation, Lewis-bases can be used to finish the formulation. Examples of components which can be in the Lewis-base addition phase include 2 , 4 , 6-tris (dimethylaminomethyl) phenol. Use of this Lewis-base allows for both suitable pot life and sufficient cure speed. In contrast, use of an alkylphenol compound such as, for example, nonylphenol in the second AAHCC does not generally provide for suitable cure.

In one embodiment of the second AAHCC, which is illustrated in the working examples below, one or more oligomeric diols are used together with a C₃-C_I0 acid functional compound in the presence of urethane catalyst and a compound providing pendant allyl unsaturation such as trimethylolpropane monoallyl ether. Suitable reaction conditions are used to prepare a pre-polymer. An isocyanate such as IPDI is then reacted with the pre-polymer composition at elevated temperatures of about 70-95 ^*C until the free NCO content is between about 3% and about 6%. This mixture is then combined with a neutralization phase before mixing with an aqueous phase. Chain extension is then carried out. At some point in this process, preferably after chain extension, the Lewis-Base addition phase is incorporated into the composition. The end result is a milky liquid composition.

The second AAHCC, therefore, is a modified single-component coating such as a polyurethane coating in which the polyurethane is modified with a series of neutralization compounds, chain-extension compounds, optional additives, and the Lewis Base. This modified coating can function synergistically with the first AAHCC and the epoxy resin and adduct to provide desired high performance for a zero-VOC two-component epoxy coating.

ACRYLIC RESIN

In a preferred embodiment, the crosslinking component further is formulated with use of one or more acrylic resins, or in particular, an emulsion or dispersion of one or more acrylic resins. The properties and cost-performance of the two-component epoxy system can be strategically tailored with use of this optional acrylic resin. For example, the second AAHCC can be tailored, if desired, with use of acrylic resin. If amine reaction with the acrylic resin occurs upon mixing, then a functionalizεd acrylic resin would result. Also, acrylic resin can be used in strategic combination with other resins such as butadiene-styrene resins.

Conventional acrylic monomers well-known in the art can be used in the acrylic resin. Monomers can be acid functionalized (e.g, acrylic acid), hydroxyl functionalized (e.g., hydroxyethyl acrylate) , nitrile functionalized (e.g., acrylonitrile) , and the like. Acrylate monomers such as methyl, butyl, or hexyl acrylate can be used. Mixtures of low Tg and high Tg monomers can be used to control polymer flexibility. Mixtures of acrylates and alkyl acrylates such as methacrylates or ethacrylates can be used. Ionic acrylic polymers can be used.

Preferred examples of acrylic emulsion include Glascol C42 and Glascol C47 (Allied Colloids) . Solids content in the acrylic emulsion can be, for example, about 30 wt.% to about 60 wt.%. According to the supplier literature, Glascol C47 is an anionic self crosslinking aqueous air drying polymer for use on, for example, internal furniture and other industrial wood substrates. Typically, the percent solids is about 42%; the neutralizing agent is ammonia; the acid value (as 100%) is 22.0; the blocking temperature is about 200 "C; the glass transition temperature is about 40 "C; the M.F.F.T. (minimum film formation temperature) is about 38 "C; and the viscosity as supplied is about 500 mPa . s .

According to supplier literature, Glascol C42 is an aqueous acrylic emulsion which provides a hard polymer with excellent resistance to oils and fats, gasoline, and chemicals. It is suitable for air dry and low force dry cure conditions, and offers versatility of application by spray, dip, flow, or direct roll helping to meet varied finishing requirements. Typically, solids content is about 45%, pH is about 6.5; viscosity (Brookfield RVT at 50 rpm) is about 30 Mpa.s; and the MFFT is about 55 ^*C.

Not all acrylics, however, perform equally in the crosslinker. The acrylic MFFT is preferably at least about 30 ^*C, and more preferably, at least about 35'C. For example, less preferred acrylics, which generally result in poorer performance, include SCX^-igβδ (SC Johnson Polymer) and Acronal LR 8958X (BASF) . According to the supplier's literature for SCX™-1965, this acrylic emulsion is for clear wood coatings. It is stated to be a waterborne thermoplastic acrylic emulsion that offers excellent print resistance, chemical resistance (50% ethanol and 70% isopropanol solutions) , and clarity. It is stated to be designed primarily to replace solvent-based nitrocellulose clears for furniture. The viscosity is 100 cps, pH is 8.2, NV by weight is 42%, MFFT('C) is 28, and density is 8.6 lbs/gal. This acrylic, according to the supplier literature, can be formulated to be a clear wood coating having a calculated VOC of 263 g/L. The supplier's literature for Acronal^®LR8958 states that this acrylic is a water-based fine particle size acrylic copolymer dispersion for the manufacture of coalescent free latex paints. The solids content is stated to be about 50%, the pH is about 8, the viscosity is about 300 cps, particle size is about 0.1 microns, the MFFT('C) is about 1. The surface appearance is clear, glossy, and tack- free .

Other polymers besides acrylics can also be used. Excellent MEK double rub values can be obtained by formulating coatings with combinations of self-crosslinking acrylics, butadiene resins, styrene-butadiene resins, vinyl acetate resins, and vinyl acrylics.

RAPID-DRY EMBODIMENT

Compositions according to this invention can be formulated for rapid-dry (with at least overnight hardness at ambient) . For example, the following process was used to prepare a rapid-dry coating:

(1) A dispersion of butadiene-styrene zero-VOC resin was mixed with a dispersion of zero-VOC acrylic resin with low acid functionality . (2) A composition was prepared by mixing water, a dispersion of butadiene-styrene zero-VOC resin, and tris-2,4,6-

(dimethylaminomethyl) phenol . This composition was mixed together with the composition of step (1) .

(3) A vinyl acrylic or vinyl acetate dispersion was mixed into the formulation of step (2) .

(4) An AAHCC was prepared from an alkylphenol such as nonylphenol, an aminoalcohol such as 2 -amino-2 -methyl-1-propanoi, a compound having two primary amine groups such as 2- methylpentanediamine, an alkanol compound such as diethanolamine, and, optionally, minor amounts of surfactant, wetting agent, and defoamer. This AAHCC was mixed into the formulation from step (3) . (5) Other ingredients such as surfactant, wetting agent, defoamer, grinding aid, and pigments are mixed into the formulation as needed .

OTHER INGREDIENTS Besides the epoxy resin, the epoxy adduct, the AAHCC, and the polyurethane and acrylic polymers, conventional additives can be used to formulate these zero-VOC coatings and paints . These additives can be used in amounts known in the art to provide the desired properties depending on the application. Conventional additives include neutralization agents, auxiliary solvents or cosolvents (which are preferably omitted for low-VOC) , film-forming agents, preservatives, thickeners including inorganic, organic, synthetic organic, and organometallic thickeners, wetting and dispersing agents, defoamers, dryers, and corrosion inhibitors. Such additives are discussed in, for example, Chapter 8 of the aforementioned Doren et al . text, Water-Borne Coatings, the complete disclosure of which is hereby incorporated by reference. In addition, Chapter 9 of the Doren text discusses pigments and fillers, the complete disclosure of which is also incorporated by reference.

Particular wetting aids include, for example, silicone surfactants BYK-345, BYK-346, and BYK-348; BYK Chemie) . Surfactants can be used as desired such as, for example, IGEPAL CA 520 (Rhone-Poulenc) which is an ethoxylated octylphenol with 5 moles of ethylene oxide. If optional organic solvents are used, an exemplary solvent is a ketone such as, for example, N-methyl-2- pyrrolidone. UN absorbers include, for example, Tinuvin 1130 (Ciba) . Light stabilizers include, for example, hindered amine light stabilizers such as, for example, Tinuvin 292 (Ciba) .

COATING METHODS AND APPLICATIONS

The epoxy component and the crosslinking component can be mixed, applied, and cured by conventional methods. For example, Chapter 11 of the aforementioned text by Doren et al., Water-Borne Coatings, describes manufacturing processes, the complete disclosure of which is hereby incorporated by reference. Manufacturing of paints and pigmented coatings can be carried out with use of grind and let down phases.

After mixing the multiple components to form the reactive precursor composition, the composition is preferably allowed to induct before application of the coating to a substrate. Even after induction, the composition remains a reactive precursor composition. The induction period generally improves crosslinking. Representative induction times are about 5 to about 10 minutes, but can be adjusted to a particular application. The present invention is not particularly limited by the size of any polymer particles formed in the carrier medium for any of the compositions used to prepare the components or the final precursor composition. Solutions, colloids, microdispersions, polymer dispersions, and emulsions can be formed during formulation. The mixture of epoxy and crosslinking components can be reduced further with water up to, for example, about 20% in order to adjust viscosity and optimize the application method.

In general, the two-component epoxy coating kit is formulated for a 2:1 wt . ratio between the epoxy crosslinking component and the epoxy resin component. However, the range can be varied between, for example, 1.2:1 to 6:1. For example, increasing the amount of epoxy will generally make the coating less expensive. Preferably, each component provides approximately the same amount of solids. The total equivalencies for the crosslinking component should at least slightly exceed that for the epoxy component. For example, the ratio of these equivalencies can be about 1.1:1 to about 1.5:1, respectively.

The epoxy equivalent weight of the epoxy component can be slightly more than the average equivalent weight of the crosslinking component. For example, this ratio can be between about 1.05:1 and about 1.5:1.

The paints or coatings can be ambiently cured or dried at about room temperature which is about 25-28 ^*C. Alternatively, elevated temperatures can be used in force drying at, for example, about 70 ^*C to about 100 'C, and preferably, at about 90 'C. Cure time at 90 'C can be accelerated to about 30 minutes. Application methods include conventional methods known in the art such as, for example, brush, roller, or spray. Spray applications are preferably at about five to about eight wet mil thickness. Conventional paint and coating dry thicknesses can be used. Advantageously, all clean-up can be accomplished with use of water. The curing process can involve physical drying, oxidative drying, thermal cross-linking, and combinations of these.

Conventional substrates can be used including wood, metals, concrete, ceramics, plastics, and the like.

In a preferred embodiment, the epoxy coating can be formulated, optionally with acrylic and/or urethane, to yield a zero-VOC two-component direct-to-metal high-gloss paint. In this embodiment, component A includes polymer dispersion, colorant, and water, whereas component B includes epoxy resin and preferably the epoxy adduct . These two components are mixed together at a ratio of two parts A to one part B. Total solids is about 60% by wt. and about 50% by volume. After mixing the components well for approximately two (2) minutes, it may be reduced with water up to twenty percent if desired to achieve suitable viscosity. Reduction is preferably carried out within 30 minutes of mixing. After mixing, the product can be allowed to stand for about 5 minutes before applying. Pot-life is about 2.5-3 hours. This coating provides an excellent high-gloss finish for applications on most types of metals, wood, concrete, plastics, and the like. The application methods include spray, brush, or roller. Typical spray applications require about a 5-10 percent water reduction. When fully cured, the gloss coating provides long-term durability and excellent chemical and acid resistance. However, epoxy resins tend to discolor in direct sunlight, so this formulation is not recommended as an exterior top-coat. Recommended uses include heavy duty equipment paint, general purpose maintenance paint, and gloss top-coating for floors. In this embodiment, both air-dry and heat-cure can be effected. The coating will cure to a tack-free finish in approximately one hour when applied at 75 ^*F and 50% relative humidity. Full-cure properties develop over a 7 to 14 day period. Heat-cure properties develop at approximately 200 'F for 30 to 60 minutes.

The following examples help further illustrate several embodiments of the present invention. These examples set forth formulas in parts by weight for the amounts of the various ingredients. Based on this disclosure, one skilled in the art could prepare formulas with variations in these amounts of, for example, about five, about ten percent, or even about twenty-five percent .

EXAMPLES

General

In the following examples, the estimated equivalent weight of the ingredient was determined in many cases after consultation with the supplier of the ingredient with consideration of the two- component epoxy application. Hence, equivalent weight was not determined by mere consideration of ingredient's molecular weight and the number of reactive functional groups.

Tap water was generally found to be suitable. Example 1

A first AAHCC which does not contain polymer was prepared by formulation according to Table I. This type of composition was used to formulate a coating further described in Examples 4 and 5.

Example 2

A second aliphatic amine hydrogen curative complex which included polymer and was of dispersion form was formulated according to Table II. This formulation strategy included use of a single component polyurethane composition. This type of composition was used to formulate a coating further described in Examples 4 and 5.

Example 3

An epoxy adduct composition was prepared by reaction of the components shown in Table III. This type of composition was used to formulate a coating further described in Examples 4 and 5. The epoxy adduct synthesis was carried out as follows: neopentyl glycol adipate; cyclohexanedimethanol, 90%; 2-methyl-2- hydroxymethyl-l,3-propanediol; trimellitic anhydride; phthalic anhydride; 1, 4-cyclohexanedicarboxylic acid; dimethylolproprionic acid; and butyl stannoic acid were charged to a one liter reaction vessel with agitator, heating and cooling jacket, condenser, thermometer, and nitrogen gas inlet for nitrogen blanketing. The reactants were added and the vessel heated to 195' to 198 "C, and all moisture was removed. The reaction was continued for approximately three hours until the acid value was approximately 50. This resin reaction mixture was then cooled to approximately 50 ^*C and the trimethylolpropane monoallyl ether was added. This entire resin complex was mixed for 20 minutes and then allowed to cool to ambient . When completed, this resin can have a viscosity, at 72 'F, of approximately 3000 CPS, an acid number of approximately 45, and a hydroxyl number of 28 to 120, preferably a 55 hydroxyl number.

Example 4

A two-component epoxy gloss paint was formulated as indicated in Table IV with use of the compositions like those in Examples 1- 3. The physical properties of the admixed and cured paint are summarized in Table V. The two-component epoxy formulation is a high gloss coating which has combinations of properties not heretofore found in zero-VOC epoxy systems.

Example 5

An additional first type of AAHCC having no added polymer was formulated as indicated in Table VI . This AAHCC generally provided for better coating appearance than the AAHCC of Example 1. This AAHCC composition was then used to formulate the coating indicated in Example 6 and Table VII.

Alternatively, this AAHCC can be used to directly crosslink epoxy resin combined with epoxy adduct. However, this embodiment of the coating did not generally provide the low viscosity or long pot life. Example 6

A coating crosslinker was formulated as indicated in Table VII. This crosslinker could be used to crosslink epoxy resin as shown in Table IV (2:1 ratio; epoxy resin used with epoxy adduct) . In formulating this coating, a composition prepared according to Table VIII was used. Compared to the coating of Example 4, this coating generally had a rapid development of hardness. In formulating this coating, the order of mixing the K54 cure accelerator was found to be important. In general, this accelerator could not merely be added to the aliphatic amine hydrogen curative complex of Example 6.

In the formulation of Table VII, pre-ground titanium was used so grind and let down phases were not needed. However, if desired, the coating can be formulated with grind and let down phases.

O 99/63016

Table I

Eαuiv. Total

Ingredients Grams Solids Weieht Equivalencies

Water (H,0) 10.0 0.0 0.00 0.00

Triethanolamine (TEA)¹ 10.0 10.0 100.00 0.10

Dimechylolproprionic acid (DMPA)² 4.0 4.0 100.00 0.04

Arninomethylpropaπol (AMP-95)³ 10.0 10.0 100.00 0.10

Diethanolamine (DEA)⁴ 10.0 10.0 34.48 0.29

2-methyipenumethyIenediamine (MPMD)⁵ 48.0 48.0 28.92 1.66

Moπoethanolaraine (MEA)⁴ 6.0 6.0 60.00 0.10

Dlmethylaminopropylamiπe (DMAPA)⁷ 2.0 2.0 66.67 0.03

Totals 100.0 90.0 38.79 2.32

Physical Properties:

Appearance Clear liquid

Viscosity @ 75 °F (CPS) 150 CPS

Specific Gravity @ 75"F .95 to .98

Density (lbs/gal) @ 75"F 8.3 to 8.6

Flash point (Closed Cup) (^βF) >300

Percent Free Water 10%

Amine Hydrogen Equivalent Weight 43 (based on total weight including water) 39 (based on solids excluding water)

Huntsman

Perstorp Specialty Chemicals

Argus Chemical Corp. (contains approximately 5% water)

Huntsman

Du Pont. DYTEK'A

Huntsman

Huntsman 99/63016

Table II

Ingredients Grams Solids Eαuiv. Wt. Eαuivalencies

Prepolymer Phase

(React the following ingredients at 80'C to 92°Cfor 2'A hours in a reaction vessel with a nitrogen blanket, under medium agitation.)

Hexaneadipate polyester diol' 100.00 100.00 1000.00 0.10

Hydroxyl functional butadiene diol² 60.00 60.00 1200.00 0.05

Dimethylolproprionic acid³ 25.00 25.00 67.56 0.37

DiburyItindilaurate-12% (catalyst)⁴ .10 .10 0.00 0.00

Trimethylolpropane monoallyl ether 3.00 3.00 75.00 0.04

188.10 188.10 335.89 0.56

(Premix the above at 82°Cfor 20 minutes, then slowly add the following.)

Isophoronediisocyanate (IPDI) 95.00 95.00 111.00 0.86

283.10 283.10 199.37 1.42

(After 2A' hours at 80'C to 92'C. the free NCO will equal 4.45%)

Neutralization Phase

Triethylamiπe⁴ 19.00 19.00 105.56 0.18

Water Phase

Water 300.00 0.00 0.00 0.00

Surfactant⁷ 20.00 10.00 0.00 0.00

Wetting Aid* 10.00 5.00 0.00 0.00

Defoamer' 2.00 1.00 0.00 0.00

332.00 16.00 0.00 0.00

Chain Extension Phase

Water 100.00 0.00 0.00 0.00

2-methylpentamethylenediamine¹⁰ 2.00 2.00 28.57 0.07

Ethyleπediamine 5.00 5.00 31.25 0.16

Diethylenetriamine" 6.00 6.00 35.29 0.17

113.00 13.00 32.50 0.40

Lewis-Base Addition Phase

Water 75.00 0.00 0.00 0.00

2.4,6- 270.00 130.00 419.00 0.31

Tris(dimethyIaminomethyl)phenol¹²

345.00 130.00 419.36 0.31

Totals 1092.10 461.10 199.61 2.31

Physical Properties

Appearance Milky Liquid

Viscosity @ 75°F (CP) 130 CPS

Specific Gravity @ 75 "F 1.1 to 1.2

Flash Point N/A (water-based)

Percent Free Water 54% to 58%

Percent solids (PBW) 42% to 46%

Acid Number 92 to 100

Amine Hydrogen Equivalent Weight 250 Table π cont.:

¹ From RUCO Polymer Corp.; RUCOFLEX Saturated Polyester Diol; Ruco S-107-55 hydroxyl number = 55 ± 3; nominal molecular weight = 2000; viscosity (Brookfield LVF Viscometer), 60"C,

2250 ± 250; slushy liquid; functionality = 2; melting range = slowly freezes below 25 'C; Acid Number = 0.6 maximum; Color (APHA) = 300; Moisture, as shipped = 0.05% maximum

²From RUCO Polymer Corp.; RUCO SI 02-40

^JFrom Perstorp Specialty Chemicals

⁴From Air Products, Dabco* T-12 Catalyst

⁵From Huls, VESTANAT* IPDI

⁴Air Products and Chemicals, Inc.

'From Union Carbide, TX 405

•From BYK Chemie

'From Air Products, DF 574

'"From Du Pont, DYTEK*A

"From BASF

^I2From Air Products, Aπcamine* K54 curing agent

Table III

Adduct Formulation

Ingredients Grams

Neopentyl glycol adipate' 11.00

Cyclohexanedimethanol, 90% 28.00

2-methyI-2-hydroxymethyI-l-3-propanediol 0.40

Trimellitic anhydride² 20.00

Phthalic anhydride 2.00

Dimethylolproprionic acid 11.00

Butyl Stannoic acid 0.10

1,4-cyclohexanedicarboxylic acid 20.00

Trimethylolpropane monoallyl ether 7.50

Totals 100.00

'Union Carbide ²Arco

O 99/63016

Table IV

Epoxy Gloss Paint Formulation

Equiv. Total

Ingredients Grams Solids Weiεht Equivalencies

Part A

Grind Phase

Water (H,0) 20.00 0.00 0.00 0.00

AAHCC-(fιrst) 12.00 11.00 39.29 0.28

Defoamer 0.10 0.00 0.00 0.00

Titanium dioxide 24.00 24.00 0.00 0.00

Wetting aid 2.00 1.00 0.00 0.00

Thickener' L50 0.50 0.00 0.00

Totals 59.60 36.50 130.36 0.28

Let-Down Phase

Acrylic resin² 25.00 11.00 0.00 0.00

AAHCC-(second) 10.00 4.50 250.00 0.04

Surface tension modifier 2.00 0.00 0.00 0.00

H,0 3.40 0.00 0.00 O.OO

Total Part A 100.00 52.00 162.50 0.32

Part B

Epoxy resin³ 46.00 46.00 190.00 0.24

Epoxy Adduct 4.00 4.00 0.00 (λOO

Totals Part B 50.00 50.00 208.33 0.24

Total Part A and Part B 150.00 102.00 182.14 0.56

'P50, From King Industries

²Cook Chemical - Chempol 4301 (acid functional acrylic resin)

³727-0100 Liquid Epoxy Resin (Peninsula Polymers, Inc.)

99/63016

Table V

Physical Properties

Admixed Paint Properties Tvnical Value Test Method

Percent solids 60% ASTM D-2369

Viscosity (after 10% H_;0 reduction) 100 CPS Brookfield (70%'F)

Specific gravity 1.21 ASTM D-2196 and D-1475 pH 7.8 to 9.5 N/A

VOC (g/L) Zero N/A

Particle size Colloidal N/A

Amine hydrogen equivalent weight 315 - Part A N/A

Epoxide equivalent weight 208 - Part B N/A

Flashpoint, closed cup >390"F ASTM D-3278

Pot-life, working time 2 1\2 hours N/A

Dry times: set to touch 1 hour ASTM D-1640

Tack-free 2 hours ASTM D-1640

Through cure 8 hours ASTM D-1640

Gloss @ 60" angle 90 ASTM D-523

Hardness (pencil) 2H ASTM D-3363

Adhesion (dry tape) 5A ASTM D-3359

Flexibility (0-T bend) Pass ASTM D-4145

Impact resistance (direct and reverse) 50 in/lbs. ASTM D-2794

Chemical resistance:

MEK double rubs 500

Acid 10% Hcl - spot test No effect ASTM D-I308

Base 10% NaOH - spot test No effect ASTM D-1308

Table VI

'TX 405 non-ionic surfactant (Rohm & Haas)

³BYK-Chemie USA (silicone additive for surface tension reduction and substrate wetting)

TABLE VII

'DL 313NA (Dow Chemical): Supplier literature indicates a solids bv weight of 48%; solids by volume of 47.1 % ; pH of 8.5; viscosity (cps) of 300; Tg (-C) or -1 ; Panicle size (angstroms) of 1550.

O 99/63016

TABLE VLTI

Claims

WHAT IS CLAIMED IS:

1. A multi-component epoxy coating prepared by drying and curing a low- or zero-VOC precursor composition, the precursor composition being a mixture of at least two components, wherein at least one component for the coating, before mixing of the components, is an epoxy component including an epoxy resin, and the epoxy component is formulated for dispersability of the epoxy resin in water, wherein at least one other component for the coating, before mixing of the components, is a curative for the epoxy component and is formulated for dispersability in water, the curative being prepared from a first aliphatic amine hydrogen curative complex which is a mixture of ingredients including, before mixing, at least one primary amine ingredient and at least one alkanolamine ingredient, wherein the amounts of the curative and the first aliphatic amine hydrogen curative complex are sufficient so that the dried and cured epoxy coating has an MEK double rub value of at least about 500.

2. A cured epoxy coating according to claim 1, wherein the precursor composition has a percent solids of at least about 40%.

3. A cured epoxy coating according to claim 1, wherein the precursor composition has a percent solids of at least about 60% .

4. A cured epoxy coating according to claim 1, wherein the MEK double rub value is at least about 1,000.

5. A cured epoxy coating according to claim 1, wherein the MEK double rub value is at least about 2,000.

6. A cured epoxy coating according to claim 1, wherein the MEK double rub value is at least about 3,000.

7. A cured epoxy coating according to claim 1, wherein the cured epoxy coating has an MEK double rub value of at least about 4,000.

8. A cured epoxy coating according to claim 1, wherein the precursor composition is zero-VOC.

9. A cured epoxy coating according to claim 1, wherein the coating has a gloss at 60 degree angle of at least 70.

10. A cured epoxy coating according to claim 1, wherein the coating has a gloss at 60 degree angle of at least 80.

11. A cured epoxy coating according to claim 2, wherein the precursor composition and the coating components are prepared without use of organic solvents.

12. A cured epoxy coating according to claim 1, wherein the precursor composition has a pot-life of at least about one hour.

13. A cured epoxy coating according to claim 12, wherein the pot-life is at least about two hours.

14. A cured epoxy coating according to claim 2, wherein the cured coating is not affected in a 10% HC1 spot test and a 10% NaOH spot test.

15. A two-component epoxy coating prepared by curing a low- or zero-VOC mixture of two components, wherein a first component, before mixing of the components, includes a water-dispersible epoxy resin or a water-dispersible reaction product of epoxy resin and an epoxy adduct, wherein a second component, before mixing of the components, is a water-dispersible curative for the epoxy component and includes a mixture of ingredients including at least one first amine compound which is a diamine having two primary amine groups, at least one second amine compound which is an alkanolamine compound, and at least one third amine compound which is a primary or a secondary amine, wherein the three amine compounds are different from each other, wherein the amount of the first amine compound is greater than the amount of either the second or third amine compound .

16. A cured epoxy coating according to claim 15, wherein the coating has an MEK double rub value of at least about 500.

17. A cured epoxy coating according to claim 15, wherein the first amine compound is a C₅-C₇ amine compound and the second amine compound is a secondary amine .

18. A cured epoxy coating according to claim 15, wherein the third amine compound has both primary amine and hydroxyl functionality.

19. A cured epoxy coating according to claim 15, wherein the first amine compound is a C_j-C₇ amine compound.

20. A cured epoxy coating according to claim 15, wherein the epoxy resin has an epoxide equivalent weight of between about 80 and about 1,000.

21. A cured epoxy coating according to claim 15, wherein the epoxy resin has an epoxide equivalent weight of between about 100 and about 500.

22. A cured epoxy coating according to claim 15, wherein the epoxy resin has an epoxide equivalent weight of between about 110 and about 300.

23. A cured epoxy coating according to claim 15, wherein the epoxy resin is a 100 percent solids liquid epoxy resin.

24. A cured epoxy coating according to claim 15, wherein the first component includes a water-dispersible reaction product of epoxy resin and an epoxy adduct .

25. A cured epoxy coating according to claim 15, wherein the cured coating is cured in an air-dry ambient temperature cure.

26. A cured epoxy coating according to claim 15, wherein the curative component is epoxy-free.

27. A cured epoxy coating according to claim 15, wherein the mixture is zero-VOC.

28. A cured epoxy coating according to claim 15, wherein at least one of the components includes acrylic.

29. A cured epoxy coating according to claim 15, wherein at least one of the components includes urethane.

30. A cured epoxy coating according to claim 15, wherein at least one of the components includes acrylic and urethane .

31. A cured epoxy coating according to claim 15, wherein the curative component further includes a mixture of ingredients, which is a mixture of aqueous polymer dispersion and at least two amine compounds and at least one phenol compound.

32. A cured epoxy coating according to claim 31, wherein the polymer dispersion is a urethane dispersion.

33. A cured epoxy coating according to claim 32, wherein the urethane is prepared from aliphatic isocyanate.

34. A cured epoxy coating according to claim 15, wherein the coating is a high-gloss coating.

35. A cured epoxy coating according to claim 15, wherein each of the three amine compounds have a molecular weight of less than 150.

36. A cured epoxy coating according to claim 15, wherein the curative component further includes a fourth amine compound.

37. A cured epoxy coating according to claim 36, wherein the curative component further includes at least one phenol compound.

38. A cured epoxy coating according to claim 15, wherein the first amine is 2-methylpentamethylenediamine and the second amine is diethanolamine.

39. A cured epoxy coating according to claim 15, wherein the curative component is formulated with use of a clear liquid mixture of amines including the first, second, and third amines, the mixture having a viscosity between about 100 and about 200 CPS.

40. A cured epoxy coating according to claim 39, wherein the clear liquid mixture has a percent free water of less than about 20%.

41. A cured epoxy coating according to claim 24, wherein the epoxy adduct is used in amounts of about 3% to about 15% parts by weight with respect to the amount of the epoxy resin and the adduct .

42. A cured epoxy coating according to claim 41, wherein the adduct, before reaction with the epoxy resin, is an acid functional polyol resin.

43. A cured epoxy coating according to claim 42, wherein the adduct is free of amino groups.

44. A cured epoxy coating according to claim 42, wherein the adduct is prepared with use of an allyl functional compound.

45. A cured epoxy coating according to claim 42, wherein the epoxy adduct, before mixing with the epoxy resin, has an acid number between about 20 and about 80 and a hydroxyl number between about 28 and about 120.

46. A cured epoxy coating according to claim 15, wherein the coating is free of acrylic.

47. A cured two-component coating prepared by cure of a low- or zero-VOC precursor composition, wherein the precursor composition consists essentially of a reactive mixture including water, epoxy resin optionally modified with acid functional polyol, and at least four different amine compounds including at least one diamine compound which has two primary amino groups .

48. A cured coating according to claim 47, wherein the precursor composition is zero-VOC.

49. A cured coating according to claim 47, wherein the precursor composition further consists essentially of acrylic resin.

50. A cured coating according to claim 49, wherein the coating, upon air-drying, has an MEK double rub resistance value of at least about 500.

51. A cured coating according to claim 50, wherein at least one of the amine compounds is an alkanolamine compound.

52. A low- or zero-VOC epoxy coating formulated to be chemically resistant and have suitable cure speed and pot life which is prepared by: mixing at least two compositions which are reactive with each other to form a precursor epoxy coating composition and begin reaction of the compositions; applying the precursor coating composition to a substrate; and allowing the precursor coating composition to dry and cure to form a cured epoxy coating; wherein at least one composition is, before mixing, an epoxy component and at least one composition, before mixing, is formulated to react with and cure the epoxy component, the curing component including at least three amine compounds including at least one primary amine compound and at least one secondary amine compound which in combination provide for at least an overnight cure at ambient temperature but also at least one hour of pot life.

53. The cured epoxy coating of claim 52, wherein the coating is a zero-VOC coating.

54. A zero-VOC epoxy coating or paint formulated from epoxy resin and a mixture of amino crosslinking compounds for the epoxy resin, wherein the amino crosslinking compounds do not include a polymeric amine compound and do include at least two amino crosslinking compounds selected from the group consisting of (i) secondary amines also having hydroxyl functionality, and (ii) diamines having two primary amino groups .

55. A low or zero-VOC two-component cured epoxy coating comprising a crosslinked molecular network including the reaction product of epoxy and amine groups, wherein the crosslinked molecular network is sufficiently crosslinked and compatible to provide an MEK double rub value of at least about 500 and a gloss value at a 60 degree angle of at least about 70.

56. A coating according to claim 55, wherein the molecular network further includes acrylic, urethane, or acrylic and urethane.

57. An article of manufacture comprising a cured epoxy coating according to claim 15.

58. A coated substrate, wherein the substrate is coated with a cured composition which is the reaction product of a low- or zero-VOC two-component epoxy coating system and providing an MEK double rub value of at least 500, at least one hour of pot life, and at least an overnight rate of cure at ambient temperature.

59. A coated substrate according to claim 58, wherein the coating system is zero-VOC.

60. A coated substrate according to claim 58, wherein the two-component epoxy coating system is an acrylic/epoxy coating system which is cured with a composition comprising a mixture of reactive amines free of polymeric amines.

61. A coated substrate according to claim 58, wherein the two component epoxy coating system is an acrylic/epoxy/urethane coating system which is cured with a composition comprising a mixture of reactive amines including at least one diamine having two primary amine groups and at least one secondary amine.

62. A coated substrate according to claim 61, wherein one component of the coating system is an epoxy component prepared by mixing a 100% solids liquid epoxy with an acid functional polyol adduct, the adduct providing for dispersion of the epoxy in water.

63. A coating kit for application of a low- or zero- VOC coating, the kit comprising multiple coating components: wherein at least one component includes an epoxy resin; wherein at least one component includes a composition which reacts with the epoxy pre-polymer composition and is formulated with at least three amine compounds, including at least one diamine compound having at least two primary amino groups and at least one secondary amine compound, wherein all coating components are formulated for low- or zero-VOC.

64. A coating kit according to claim 63, wherein the kit is for application of a zero-VOC coating.

65. A coating kit according to claim 63, wherein the kit further includes an epoxy adduct to improve the dispersability of the epoxy resin in water, wherein the epoxy adduct is either pre-mixed with the epoxy resin or is included in the kit as a composition separate from the epoxy pre-polymer.

66. A coating kit according to claim 63, wherein the coating, upon cure, provides for an MEK double rub value of at least 500.

67. A composition formulated for use in curing an epoxy resin in a multi-component low- or zero-VOC coating system, the composition being prepared from a mixture of ingredients including at least two alkanolamine compounds and at least one amine compound having two primary amine groups, wherein the amounts of the mixture of ingredients are selected to provide both at least overnight ambient temperature cure speed and at least one hour of pot life in the low- or zero-VOC coating system.

68. A composition according to claim 67, wherein the coating system is zero-VOC.

69. A composition according to claim 67, wherein the ingredients further include at least a third alkanolamine compound.

70. A composition according to claim 67, wherein the ingredients further include at least a third alkanolamine which has a primary amine group and a hydroxyl group.

71. A composition according to claim 67, wherein the ingredients further include a phenolic compound.

72. A composition formulated for use in curing an epoxy resin in a multi-component low- or zero-VOC coating system, the composition being prepared by mixture of ingredients including an alkylphenol, a tertiary amine compound having three hydroxyl groups, a primary amine compound having a methyl group and a hydroxyl group, a secondary amine compound having two hydroxyl groups, and an amine compound having two primary amine groups .

73. A composition according to claim 72, wherein the composition is formulated for use in a zero-VOC coating system.

74. A composition according to claim 72, wherein the amount of alkylphenol is about 4 wt.% to about 20 wt.%, the amount of tertiary amine compound having three hydroxyl groups is about 7 wt.% to about 27 wt.%, the amount of primary amine compound having a methyl group and a hydroxyl group is about 7 wt.% to about 27 wt.%, the amount of secondary amine compound having two hydroxyl groups is about 7 wt.% to about 27 wt.%, and the amount of amine compound having two primary amine groups is about 20 wt.% to about 50 wt.%.

75. A composition according to claim 72 , wherein the composition has a water content of less than about 2 wt.%.

76. A composition according to claim 72, wherein the composition is substantially water-free.

77. A composition according to claim 72 , wherein the composition is substantially free of polymeric amine.

78. A composition according to claim 72, wherein the alkylphenol compound is nonylphenol, the tertiary amine compound having three hydroxyl groups is triethanolamine, the primary amine compound having a methyl group and a hydroxyl group is 2-amino-2-methyl-l-propanol, the secondary amine compound having two hydroxyl groups is diethanolamine, and the amine compound having two primary amine groups is 2- methylpentamethylenediamine .

79. A composition for use in curing an epoxy resin in a multi-component low- or zero-VOC coating system, the composition being prepared from the ingredients comprising at least three alkanolamines and a diamine compound having two primary amino groups.

80. A composition according to claim 79 further including an acid-functional diol compound.

81. A composition according to claim 79, wherein the coating system is zero-VOC.

82. A composition according to claim 79 further including water.

83. A composition for use in curing an epoxy resin in a multi-component low- or zero-VOC coating system, the composition being prepared from the ingredients comprising:

(i) about 0 parts to about 20 parts by weight water,

(ii) about 3 parts to about 20 parts by weight of a first alkanolamine,

(iii) about 0 parts to about 10 parts by weight acid functional diol,

(iv) about 3 parts to about 20 parts by weight of a second alkanol amine,

(v) about 3 parts to about 20 parts by weight of a third alkanolamine, and

(vi) about 30 parts to about 70 parts by weight 2- methylpentamethylenediamine .

84. A polymer-free epoxy aliphatic amine hydrogen curative complex comprising 2-methylpentamethylenediamine and at least two alkanolamines, wherein the complex is formulated for a low- or zero-VOC epoxy coating system.

85. A complex according to claim 84, wherein formulation is for a zero-VOC epoxy coating system.

86. The complex according to claim 84, the complex further comprising a phenolic compound.

87. The complex according to claim 86, the phenolic compound being an alkylphenol .

88. The complex according to claim 87, wherein the alkylphenol is nonylphenol.

89. The complex according to claim 86, wherein the phenolic compound is 2,4, 6- (dimethylaminomethyl) phenol .

90. A dispersion for use in curing a multi-component low- or zero-VOC epoxy coating system, the dispersion being prepared from a mixture of (i) a single-component aliphatic polyurethane dispersion in water, (ii) at least one amine compound having two primary amine groups, (iii) at least one diamine or triamine compound different from the amine compound having two primary amine groups, and (iv) at least one phenol compound.

91. An epoxy adduct composition which is a reaction product of ingredients which include a cycloalkane diol compound, a compound having both anhydride and carboxylic acid functionality, a cycloalkane dicarboxylic acid compound, a polyester diol, and a compound providing both a pendant allyl group and at least two functionalities to bind the compound covalently with the adduct.

92. A modified epoxy resin which is the reaction product of an epoxy adduct composition according to claim 91 and an epoxy resin.

93. A method of coating a substrate without substantial use of volatile organic compounds, the method comprising the combination of steps: mixing an epoxy component and a crosslinking component to form a precursor composition; wherein both epoxy and crosslinking components are substantially free of volatile organics; applying a coating of the mixed precursor composition to a substrate; curing the pre-cursor composition on the coated substrate; wherein the composition cures to form a coating having an MEK double rub value of at least 500.