MXPA00004427A - Water compatible curing agents for epoxy resins - Google Patents

Abstract

A novel water compatible curing agent for epoxy resins is provided. The curing agent can be made by (a) reacting at least one polyamine having at least 3 active amine hydrogen atoms per molecule and at least one epoxy resin having a functionality of at least 1.5 in an epoxy functionality equivalents to polyamine mole ratio of 0.9:1 to 1:10 thereby producing an amine-terminated intermediate;(b) reacting the amine-terminated intermediate with 0.5 to 25 weight percent, based on the amine-terminated intermediate, of an acid-terminated polyalkyleneglycol-containing compound having formulae (I), (II) and (III) wherein R1 is an alkyl, aryl, or arylalkyl group having 1 to 15 carbon atoms, X and Y are independently a hydrogen, methyl, or ethyl group with the provision that if X is methyl or ethyl, Y is hydrogen or if Y is methyl or ethyl, X is hydrogen, and n + m + o is a real number from 100 to 200, and n + o is at least 70 percent of n + m + o, and in a ratio of (I) to (II) by weight in the range of 100:0 to 0:100, and in a ratio of (I) to (III) by weight in the range of 100:0 to 0:100, and in a ratio of (II) to (III) by weight in the range of 100:0 to 0:100, until essentially all of the acid group is consumed. Such amine-terminated curing agent can also be capped with a monoepoxy. The curing agent can also be made (a) reacting at least one polyamine described above and an epoxy resin thereby producing an amine-terminated intermediate;(b) reacting the amine-terminated intermediate with a monoepoxy to provide a capped amine-terminated intermediate;then (c) reacting the capped amine-terminated intermediate with an acid-terminated polyalkyleneglycol-containing compound described above.

Description

CURING AGENTS COMPATIBLE WITH WATER FOR EPOXYTIC RESINS The present invention relates to curing agents for epoxy resins. In one aspect, the invention relates to curing agents suitable for use in flotation applications.

Epoxy coating systems cured with polyamine-based curing agents are used for the preparation of coatings for industrial maintenance and other types of protective coatings for a variety of substrates. Epoxy resins that have excellent resistance to chemicals also have good adhesion to most substrates, for example, various woods, laminated wood for walls, metals and masonry surfaces.

For a long time it has been a desire to formulate a curing agent, which is essentially free of volatile organic compounds (VOC's), which are self-emulsifying and curable over a wide range of temperatures in the absence of external accelerators if possible.

Ref. 0119655 Many of the floating epoxy resins and current curing agents are pestered with the problem of poor film properties, because the surfactants tend to migrate to the surface during curing of the resin system. Thus, it would be desirable to provide a curing agent system containing a surfactant, which does not migrate during curing, ie, a system compatible with water, which does not require surfactant salt, for example, with acids, or using plasticizers to form a stable dispersion of the curing agent in water.

Curing agents compatible with water can be soluble (homogenized), dispersible (dispersions of oil in water), or provide dispersions of water in oil.

In addition to providing a curing agent compatible with water, the curing agent would be readily compatible with a floating epoxy resin to make a coating having good mechanical properties and good strength properties. A floating curing agent that does not have good compatibility with the epoxy resin will bind poorly when applied to a substrate. The compatibility problem is more acute where the primary amine groups of the curing agent have been converted to secondary amine groups to reduce the phenomenon of fluorescence and nebulosity due to the formation of carbamates.

It is desirable to obtain curing agents that are compatible with water and provide cured products with good mechanical properties and good strength properties.

A curing agent for epoxy resins comprising a reaction product prepared by the steps comprising: (a) reacting at least one polyamine having at least 3 active amine hydrogen atoms per molecule and at least one epoxy resin having a functionality of at least 1.5 at a mole ratio of epoxy to polyamine functionality equivalents of 0.9 : 1 to 1:10, whereby an intermediate product finished in amine is produced; (b) reacting the finished intermediate in amine with 0.5 to 25 percent by weight, based on the amine-terminated intermediate, of a compound containing polyalkylene glycol terminated in acid having the formula: (1) (II) (III) wherein R1 is an alkyl, aryl, or arylalkyl group having 1 to 15 carbon atoms, X and Y are independently a hydrogen, methyl or ethyl group with the proviso that if X is methyl or ethyl, Y is hydrogen or Y is is methyl or ethyl, X is hydrogen, and n + m + o is a real number from 100 to 200, and n + o is at least 70 percent of n + m + o, in a ratio of (I) to (II) by weight in the range of 100: 0 to 0: 100, a ratio of (I) to (III) by weight in the range of 100: 0 to 0: 100, and in a ratio of (II) to (III) by weight in the range of 100: 0 to 0: 100, until essentially the entire acid group is consumed, whereby the amine-terminated curing agent is produced.

Such an amine-terminated curing agent may also be crowned with a monoepoxy to give a cured amine curing agent of the invention.

Also provided is a curing agent for epoxy resins comprising a reaction product prepared by the steps comprising: (a) reacting at least one polyamine having at least 3 active amine hydrogen atoms per molecule and at least one epoxy resin having a functionality of at least 1.5b in a mol ratio of epoxy to polyamine functionality equivalents of 0.9: 1 to 1:10, whereby an intermediate finished in amine is produced; (b) reacting the amine terminated intermediate with a monoepoxy at a ratio of amine hydrogen atoms to epoxy groups of 1.5: 1 to 30: 1 to give a finished product in a crowned amine; (c) reacting the finished intermediate product in amine capped with 0.5 to 25 weight percent, based on the intermediate finished product in crowned amine, of a compound containing polyalkylene glycol terminated in acid having the formula: (I) (II) (III) wherein R1 is an alkyl, aryl, or arylalkyl group having 1 to 15 carbon atoms, X and Y are independently a hydrogen, methyl or ethyl group with the proviso that if X is methyl or ethyl, Y is hydrogen or Y is is methyl or ethyl, X is hydrogen, and n + m + o is a real number from 100 to 200, and n + o is at least 70 percent of n + m + o, in a ratio of (I) to (II) by weight in the range of 100: 0 to 0: 100, a ratio of (I) to (III) by weight in the range of 100: 0 to 0: 100, and in a ratio of (II) to (III) by weight in the range of 100: 0 to 0: 100, until essentially the entire acid group is consumed, whereby the curing agent finished in crowned amine is produced.

The most preferred acid-terminated polyalkylene glycol-containing starting compounds are those, where m = 0.

It has been found that a certain amine adduct curing agent containing a part of polyether amidoamine is compatible in water without an acid, thereby providing a superior curing agent for floating epoxy coating formulations. In addition, the curing agent of the invention requires only small amounts of surfactant based on the solids content. The curing agents of this invention when combined with a solid or liquid epoxy aqueous dispersion give coatings with good impact resistance, high gloss and / or gloss retention.

The floating curing agent composition of the invention may be water soluble or dispersed in water (dispersion of oil in water where the continuous phase comprises water and the solid phase comprises the curing agent composition) or the water can be dispersed in the curing agent (dispersion of water in oil where the continuous phase comprises the curing agent ). The dispersion can be a suspension, emulsion, or colloidal dispersion. The aqueous phase may contain other liquids in admixture, but is preferably free of any volatile organic compound and free of any cosolvent. An aqueous phase that is essentially free of volatile organic compounds means that 5% by weight or less, preferably less than 1% by weight of the composition of the floating curing agent is a volatile organic compound.

For illustrative purposes, one embodiment of the curing agent of the invention can be represented as an amine-terminated curing agent having the simplified formula: (IV) where (V) wherein R1 is an alkyl, aryl, or arylalkyl group having 1 to 15 carbon atoms, R2 and R3 are independently an aliphatic, cycloaliphatic, or aromatic group having 2 to 18 carbon atoms, optionally containing unreactive oxygen or at most an average of 4 atoms of secondary and / or tertiary nitrogen per structure in the main structure, X and Y are independently a hydrogen, methyl or ethyl group with the proviso that if X is methyl or ethyl, Y is hydrogen or yes Y is methyl or ethyl, X is hydrogen, and n + m + o is a real number from 100. up to 200, and n + o is at least 70 percent, preferably 90 percent, of n + m + o, while more preferably m = 0. These curing agents can preferably be end-capped with a monoepoxy by reacting the epoxy groups of the monoepoxy with at least a portion of the remaining primary or secondary amine groups.

For illustrative purposes, another embodiment of the curing agent of the invention may be represented as an amine-terminated curing agent having the simplified formula: where (VII) wherein R2, R3, X, Y, n, m, and o are as described above. As the above structure, these curing agents can preferably be end-capped with a monoepoxy by reacting the epoxy groups of the monoepoxy with at least a portion of the remaining primary or secondary amine groups.

For additional illustrative purposes, another embodiment of the curing agent of the invention can be represented as an amine-terminated curing agent having the simplified formula: (VIII) where [V] wherein R1, R2, R3, X, Y, n, m and o are as described above, and R4 is an alkyl, aryl, or arylalkyl group having 1 to 15 carbon atoms.

For additional illustrative purposes, another embodiment of the curing agent of the invention can be represented as an amine-terminated curing agent having the simplified formula: : ??) where (VII) wherein R2, R3, X, Y, n, m, and o are as described above, and R4 is an alkyl, aryl, arylalkyl group having 1 to 15 carbon atoms.

One embodiment of the above curing agents can be prepared by reacting an amine-terminated compound represented by the simplified formula: (X) wherein R2 and R3 are as described above, with a compound containing polyalkylene glycol terminated in acid having the formula: (I) (II) J I I) wherein R1, X, Y, n, m, I are as described above at a ratio of hydrogen from amine to carboxyl group from 100: 1 to 1000: 1, in a proportion of (I) to (II) by weight in the range of 100: 0 to 0: 100, a ratio of (I) to (III) by weight in the range of 100: 0 to 0: 100, and in a proportion of (II) to (III) in the range of 100: 0 to 0: 100, until essentially the entire acid group is consumed, whereby the amine-terminated curing agent is produced. These curing agents can then be crowned at the end to give a curing agent based on amine crowned at the end.

In another embodiment of the curing agent, the curing agents can be prepared by reacting the finished compound in amine, which can be represented by the formula (X) with at least one monoepoxy, then reacted with at least one compound that contains polyalkylene glycol terminated in acid as depicted above.

In one embodiment, the curing agent can be prepared by reacting the acid-terminated polyalkylene glycol-containing compound of structures (I) and (II) in a proportion of (I) to (II) by weight in the range of 99: 1 to 1:99, preferably in the range of 20:80 to 80:20, and at least one amine-terminated compound. In another embodiment, the curing agent can be prepared by reacting the acid-containing polyalkylene glycol-containing compound of structures (II) and (III) in a proportion of (II) to (III) by weight in the range of 99: 1 to 1:99, preferably in the range of 20:80 to 80:20, and at least a compound finished in amine. In still another embodiment, the curing agent can be prepared by reacting the acid-terminated polyalkylene glycol-containing compound of structures (I) and (III) in a proportion of (I) to (III) by weight in the range of 99: 1 to 1:99, preferably in the range of 20:80 to 80:20, and at least one compound finished in amine. In addition, the curing agent can be prepared by reacting the acid-terminated polyalkylene glycol-containing compound of structures (I), (II) and (III) in an amount of 4 to 98 percent by weight of (I), 1 to 95 percent by weight of (II), and 1 to 95 percent by weight of (III) with at least one compound finished in amine.

The acid-terminated polyalkylene glycol-containing compound is contacted with the amine-terminated compound under conditions effective to react the amine group and the acid group. Typically, the acid-terminated polyalkylene glycol-containing compound is present in an amount of 0.5 to 25 percent by weight, preferably 1.5 to 8.0 percent by weight, based on the amine-terminated intermediate. The ratio of hydrogen atoms of amine to carboxyl group from 100: 1 to 1000: 1 is preferred. The reaction is typically carried out at a temperature from room temperature to an elevated temperature sufficient to react the amine group and the acid group preferably in the range from 150 ° C to 200 ° C for an effective time to produce the products of reaction. The progress of the reaction can be verified and established as an objective to produce the desired product by measuring the equivalent weight of amine and the acid groups of the reaction mixture. Generally, the reaction mixture is heated until essentially all of the acid group is consumed, which is typically less than 5 mg. of KOH / g, preferably less than 2 mg. of KOH / g, of the remaining acid group.

Of course, when a multifunctional epoxy resin is used in place of a difunctional epoxy resin to produce the amine-terminated compound of formula (X), the R3 group will have more than two epoxy residue groups, which can react with the polyamines. To simplify the illustration, those curing agents using the multifunctional epoxy resin or a polyamine having more than 4 equivalents of amine hydrogen functionality are not illustrated as the structure, but are included in the invention.

The amine-terminated compound of formula (X) and the multifunctional equivalents can be produced by reacting an epoxy resin with an excess of the polyamine under conditions effective to react the amine group and the epoxide group to produce an amine-terminated product. .

The reaction is typically carried out at a temperature from room temperature to an elevated temperature sufficient to react the amine group and the epoxide group preferably within the range of 60 ° C to 120 ° C for an effective time to produce the products of reaction. The progress of the reaction can be verified and set as an objective to produce the desired product by measuring the amine equivalent weight and the epoxy equivalent weight of the reaction mixture. Generally, the reaction mixture is heated until the epoxy equivalents are consumed.

If desired, the amine-terminated curing agent product can be reacted with a mono-epoxy at a ratio of remaining active amine hydrogen atoms to epoxy groups in the range from 1.5: 1 to 30: 1, preferably from 2: 1 to 20: 1, preferably from 2: 1 to 10: 1, to give a crowned product.

The finished product in amine can be crowned with a monoepoxy by reacting the compounds under conditions effective to react the remaining active amine hydrogen atoms with the epoxy groups, either before or after emulsification. The reaction is typically carried out at a temperature within the range of 60 ° C to 120 ° C for an effective time to produce the reaction products. Generally, the reaction mixture is heated until the epoxy equivalents are consumed.

Alternatively, the amine-terminated intermediate (amine-terminated compound) is first at least partially crowned, then reacted with the acid-terminated polyalkylene glycol-containing compound in a similar manner.

The preferred polyamine can be represented by the formula: H N- -R "- H2 (XI) wherein R is an aliphatic, cycloaliphatic, or aromatic group having 2 to 18 carbon atoms, optionally containing unreactive oxygen or at most an average of 4 secondary and / or tertiary nitrogen atoms per molecule in the main structure. Examples of suitable diamines include, for example, m-xylylenediamine, 1,3-bisaminomethylcyclohexane, 2-methyl-l, 5-pentanediamine, 1-ethyl-l, 3-propanediamine, ethylenediamine, diethylenetriamine (DETA), triethylenetetramine (TETA), polyoxypropylenediamines, 2, 2 (4), 4-trimethyl-l, 6-hexanediamine, isophorone diamine, 2,4 (6) -toluenediamine, 1,6-hexanediamine, 1,2-diaptincyclohexane and para-aminodicyclohexyl methane (PACM).

Preferably, the curing agent is prepared by reacting a polyalkylene glycol alkyl ether terminated in acid having the formula R1 or - (- CH2 H2 0- -CH2- -CH wherein R1 is an alkyl, aryl, or arylalkyl group having 1 to 15 carbon atoms, or is a real position number from 100 to 200, and at least one diamine in an amine to acid equivalent ratio of 6: 1 up to 25: 1.

Another, more preferred embodiment is formed by those, wherein the polyalkylene glycol alkyl ether terminated in acid is prepared by reacting a compound containing polyalkylene glycol terminated in acid having the formula wherein R1 is an alkyl or arylalkyl group having 1 to 15 carbon atoms, or is a positive real number from 100 to 200, and at least one intermediate product amine terminated at a ratio of amine to acid equivalent of 6: 1 to 25: 1.

The polyalkylene glycol containing compound terminated in acid can be produced by oxidation of a polyethylene glycol monoalkylether or a monoalkylether of a block copolymer of ethylene oxide and propylene oxide or butylene oxide ("polyalkylene glycol") or by at least partial oxidation of a polyethylene glycol, or a block copolymer of ethylene oxide and propylene oxide or polybutylene oxide ("polyalkylene glycol").

The polyalkylene glycols generally contain a distribution of compounds with a variable number of oxyethylene units, number one and / or oxypropylene or oxybutylene units, m. Generally, the quoted number of units is the total number closest to the statistical average, and the maximum point of the distribution. The positive real number as used here refers to a number which is positive and includes integers and fractions of integers.

Compounds containing polyalkylene glycol terminated in acid can be produced by oxidation of the polyalkylene glycols including, but not limited to, the processes described in U.S. Patent Numbers. 5,250,727 and 5,166,423. Generally, the oxygen-containing gas is added to the polyalkylene glycol in the presence of a free radical (eg, 2, 2, 6, 6-tetramethyl-1-piperidinyloxy) and an inorganic acid (eg, nitric acid) to produce the carboxylic acid to at least one hydroxyl group per molecule, or if the polyalkylene glycol terminated in diacid it is desired that substantially all alcohol groups are oxidized to carboxylic acid groups. The acid-terminated polyalkylene glycol-containing compound can also be made by synthesis of illiamson ether, where a polyalkylene glycol is reacted with chloroacetic acid and / or esters in the presence of a base.

The epoxy resins used in producing the curing agent can be any reactive epoxy resin having an equivalence (functionality) of 1,2-epoxy, on the average, at least 1.5, preferably at least 1.6, preferably up to 8 groups of epoxide, preferably up to 5 epoxide groups per molecule. The epoxy resin may be saturated or unsaturated, linear or branched, aliphatic, cycloaliphatic, aromatic or heterocyclic, and may have substituents which do not materially interfere with the reaction with the carboxylic acid. Such substituents may include bromine or fluorine. These may be monomeric or polymeric, liquid or solid, but are preferably liquid or a low melting point solid at room temperature. Suitable epoxy resins include glycidyl ethers prepared by reacting epichlorohydrin with a compound containing at least 1.5 aromatic hydroxyl groups, carried out under alkaline reaction conditions. Examples of other epoxy resins suitable for use in the invention include diglycidyl ethers of dihydric compounds, epoxy novolacs and cycloaliphatic epoxides. Suitable epoxy resins are described in U.S. Patent Number. 5,602,193. Generally epoxy resins contain a distribution of compounds with a variable number of repeating units.

Preferably the epoxy resin is a diglycidyl ether of a dihydric phenol, diglycidyl ether of a hydrogenated dihydric phenol, an aliphatic glycidyl ether, epoxy novolac or a cycloaliphatic epoxy.

The diglycidyl ethers of dihydric phenols can be produced, for example, by reacting an epihalohydrin with a dihydric phenol in the presence of an alkali. Examples of suitable dihydric phenols include: 2,2-bis (4-hydroxyphenyl) propane (bisphenol-A); 2, 2-bis (4-hydroxy-3-tert-butylphenyl) propane; 1,1-bis (4-hydroxyphenyl) ethane; 1,1-bis (4-hydroxyphenyl) isobutane; bis (2-hydroxy-1-naphthyl) methane; 1,5-dihydroxynaphthalene and 1,1-bis (4-hydroxy-3-alkylphenyl) ethane. Suitable dihydric phenols can also be obtained from the reaction of phenol with aldehydes, such as formaldehyde (bisphenol-F). The diglycidyl ethers of dihydric phenols include breakthrough products of the above diglycidyl ethers of dihydric phenols with dihydric phenols, such as bisphenol-A, such as those described in U.S. Patent Numbers. 3,477,990 and 4,734,468.

The diglycidyl ethers of hydrogenated dihydric phenols can be produced, for example, by hydrogenation of dihydric phenols followed by glycidation with an epihalohydrin in the presence of a Lewis acid catalyst and subsequent formation of the glycidyl ether by reaction with sodium hydroxide. Examples of suitable dihydric phenols are listed above.

The aliphatic glycidyl ethers can be produced, for example, by reacting an epihalohydrin with an aliphatic diol in the presence of a Lewis acid catalyst, followed by conversion of the halohydrin intermediate to the glycidyl ether by reaction with sodium hydroxide. The aliphatic diol can be linear or branched or substituted with oxygen in the main structure. Examples of suitable aliphatic glycidyl ethers include, for example, diglycidyl ethers of 1,4-butanediol, neopentyl glycol, cyclohexanedimethanol, hexanediol, polypropylene glycol, and similar diols and glycols; and triglycidyl ethers of trimethylol ethane and trimethylol propane.

Epoxy novolacs can be produced by condensation of formaldehyde and a phenol, followed by glycidization by reaction of an epihalohydrin in the presence of an alkali. The phenol group of the phenoxymethylene units of the epoxy novolac can be unsubstituted, partially substituted or substituted up to three substitutions with an alkyl group having 1 to 10 carbon atoms. The phenol can be, for example, phenol, cresol, nonylphenol and t-butylphenol. Epoxy novolacs generally contain a distribution of compounds with a variable number of glycinated phenoxymethylene units, r, where r is generally 2 to 8. Generally, the quoted number of units is the number closest to the statistical average, and the maximum point of the distribution.

Cycloaliphatic epoxides can be produced by converting a cycloalkene-containing compound with more than one olefinic bond to peracetic acid to an epoxide. Examples of cycloaliphatic epoxides include, for example, 3,4-epoxycyclohexylmethyl- (3, 4-epoxy) cyclohexane carboxylate, [2- (3,4-epoxy) cyclohexyl-5, 5-spiro (3,4-epoxy) ) -cyclohexane-m-dioxane] of diepoxy dicycloaliphatic diether, bis (3,4-epoxy-cyclohexylmethyl) adipate, bis (3,4-epoxycyclohexyl) adipate and [4- (1,2-epoxyethyl) -1, 2 -epoxycyclohexane] of vinylcyclohexene dioxide. Cycloaliphatic epoxides include compounds of the formulas: (XIV) (XV) Commercial examples of preferred epoxy resins include, for example, EPON Resins DPL-862, 828, 826, 825, 1001, 1002, EPONEX Resin 1510, HELOXI Modifiers 32, 44, 48, 56, 67, 68, 71, 84, 107, 505, EPON Resin DPS155, and EPON Rsein HPT 1050, all available from Shell Chemical Company, Dow Chemical Epoxy Resin DEN 431 and Union Carbide Epoxy Resins ERL-4221, -4289, -4299, -4234 and -4206 (EPON, EPONEX and HELOXI are trademarks).

The monoepoxide coping agent can be an aliphatic, alicyclic, or aromatic compound linked to the epoxy functional group. Reacting the primary amine hydrogen reduces the possibility for the formation of carbamates from the atmospheric moisture which reacts with the primary amine hydrogens, which appears as a pink color in the coating and which leads to chain cleavage. In addition to reducing the erubescence effect by reacting certain or all of the primary amine groups on the substituted aryl amidopolyamine, reacting the amidopolyamine with an epoxy functional group has the advantage of leaving some active free amine hydrogen for reaction with the epoxy groups. By reacting the primary amine in the amidopolyamine compound with an epoxy functionality, however, it leaves the secondary amine hydrogen more active for reaction with an epoxy resin. In this way, the double advantage of reducing the pink color can be achieved, while sufficient reactivity is retained to cure the system at ambient temperatures in the absence of external catalysts. The reaction with a monoepoxy crowning agent also leads to the formation of a hydroxyl group, which would also be useful for reacting with the epoxy compound.

Preferred examples of monoepoxide corking agents which are suitable for use in the invention include: I wherein R10 and R12 are the same or different and are a branched or linear alkyl group, an alkalicyclic, polyoxyalkyl, or alkenyl having 2-100 carbon atoms, optionally branched; and Ru is hydrogen, halogen or a branched or unbranched alkyl having 1-18 carbon atoms. There may be more than one type of Ru group attached to the aromatic ring.

These categories would include butylene epoxy unsaturated hydrocarbons, cyclohexane, styrene oxide and the like; epoxyethers of monovalent alcohols, such as methyl, ethyl, butyl, 2-ethylhexyl, dodecyl and others; epoxides of the alkylene oxide adducts of alcohols having at least 8 carbon atoms by the consecutive addition of alkylene oxide to the corresponding alkanol (ROH), such as those labeled under the name NEODOL (NEODOL is a trademark); epoxyethers of monovalent phenols, such as phenol, cresol, and other substituted phenols in the ortho, meta, or para positions with alkyl, aralkyl, alkylaryl, or branched or unbranched C 1 -C 2 alkoxy groups, such as nonylphenol; glycidyl esters of monocarboxylic acids, such as the glycidyl ester of caprylic acid, the glycidyl ester of capric acid, the glycidyl ester of lauric acid, the glycidyl ester of stearic acid, the glycidyl ester of arachidic acid and the glycidyl ester of alpha, alpha-dialkyl monocarboxylic acids described in US Patent Number 3, 178, 454; epoxyesters of unsaturated alcohols or unsaturated carboxylic acids, such as the glycidyl ester of neodecanoic acid, methyl oleate converted to epoxide, n-butyl oleate converted to epoxide, methyl palmitoleate converted to epoxide, converted ethyl linoleate in epoxy and the like; phenylglycidyl ether; allylglycidyl ethers, and glycidaldehyde acetals.

Specific examples of monoepoxide co-terminating agents useful for the practice of the invention include alkylglycidyl ethers having 1-18 linear carbon atoms in the alkyl chain, such as butylglycidyl ether or a mixture of C 8 -C 14 alkyls, cresylglycidyl, phenylglycidyl ether, nonylphenylglycidyl ether, p-tert-butylphenylglycidyl ether, 2-ethylhexylglycidyl ether, and the glycidyl ester of neodecanoic acid.

The curing agent of the invention can be useful for curing a solid or liquid epoxy resin, pure, in organic solvents or in water. Any epoxy resin mentioned above for producing the curing agent of the invention can be cured by the curing agent of the invention. The curing agent can be useful for coating applications to the environment, as well as baking coating applications. The curing temperature may vary depending on the application, typically in the range of 5 ° C to 200 ° C.

In addition, the curing agent of the invention can be dispersed or solubilized in an aqueous solution. Such a solution, emulsion or dispersion contains water and the curing agent of the invention. Such a composition can be provided by mixing the water in the curing agent of the invention with or without the presence of a surfactant. Any conventional surfactant useful for the emulsification or dispersion of curing agents in aqueous solutions can be used. Examples of such a surfactant are surfactants based on polyalkylene oxide blocks, such as CARBOMAX 8000, PLURONIC 88, NOVEPOX TAN 117, and JEFFAMINE ED2001 (CARBOMAX, JEFFAMINE, NOVEPOX TAN and PLURONIC are trademarks). However, the curing agents of the invention are self-emulsifying and do not need any additional surfactant (s) to give the solution, emulsion or dispersion of aqueous curing agent.

These curing agents of the invention can be used to effectively cure an aqueous epoxy resin system. Preferred examples of the aqueous epoxy resins are epoxy resins based on bisphenol-A having from 350 to 10,000 molecular weight dispersed nonionically in water with or without glycol ether co-solvents. Commercial examples of the aqueous epoxy resins include, for example, EPIREZ Resin 3520, 3522, 3540 and 5522 available from Shell Chemical Company (EPIREZ is a trademark). The curing agents of the invention are compatible with aqueous dispersions without the use of acid salts. These curable systems contain, water, one or more epoxy resins and one or more curing agents of the invention. These aqueous curable epoxy resin systems can be cured at room temperature or elevated temperatures or further catalyzed with a commercially available tertiary amine accelerator, such as 2, 4,6-tris (dimethylaminomethylphenol) or phenols to cure at lower temperatures. Examples of such materials are EPICURE Curing Agent 3253 from Shell Chemical Company (EPICURE is a trademark) or DMP-30 from Rohm and Haas. These low temperatures typically range from 5 ° C to 20 ° C. For aqueous epoxy resin systems, the typical curing temperature with or without an accelerator ranges from 5 ° C to 45 ° C. Typically these curing agents are used to formulate thermoset coatings that have good corrosion protection of the coated substrate.

These aqueous epoxy resin systems can serve as components of paints and coatings for application to substrates such as, for example, metal structures or cementitious structures. To prepare such paints and coatings, these resins are mixed with primary extenders and anticorrosive pigments, and optionally, additives, such as surfactants, antifoam agents, rheology modifiers and usual wear and slip reagents. The selection and quantity of these pigments and additives depends on the intended application of the paint and is generally recognized by those skilled in the art.

The curing agents of the present invention can also be used as adhesive components and fiber sizing.

Illustrative Modality EPON 828: is a liquid epoxy resin of diglycidyl ether, commercially available from Shell Chemical Company.

EPON lOOl-x-75: is a xylene solution of a solid diglycidyl ether epoxy resin, commercially available from Shell Chemical Company.

DEN 438-T-70: is an epoxy phenolic novolac resin in a toluene solution, commercially available from the Dow Chemical Company (DEN is a trademark).

EPON HPT 1050: is an epoxy phenolic novolac resin available from Shell Chemical.

TETA: is triethylene tetramine commercially available from Union Carbide having a typical amine value of approximately 1436 mg KOH / g (TETA is a trademark).

DYTEK A: is 2-methyl-pentyl diamine commercially available from DuPont having a typical amine value of approximately 943 mg KOH / g (DYTEK A is a trademark).

HELOXI Modifier 62: is a commercial grade orthocresol glycidyl ether available from Shell Chemical Company, which is produced by treatment of orthocresol with epichlorohydrin and sodium hydroxide. HELOXI Modifier is a non-dense liquid having a viscosity at 25 ° C of about 7 centipoise and an epoxy equivalent weight of about 175 to about 195.

CARDURA Resin E10: is the glycidyl ester of a synthetic saturated monocarboxylic acid, commercially available from Shell Chemical Company. CARDURA E10 is a non-dense liquid that has a viscosity at 25 ° C of approximately 7.1 centipoise and an equivalent epoxy weight of approximately 250 (CARDURRA is a trademark).

EPIREZ Resin 3520 (a dispersion of aqueous epoxy resin of diglycidyl ether of bisphenol-A having an EEW of 535) available from Shell Chemical Company.

EPIREZ Resin 5522 (a dispersion of aqueous modified epoxy resin of diglycidyl ether of bisphenol-A having an EEW of 625) available from Shell Chemical Company.

The following illustrative embodiments describe the novel curing agent composition of the invention and are given for illustrative purposes and are not intended to limit the invention.

Example 1 Step 1: A solution of 187 grams of toluene and EPON Resin 828 (187 grams, 1.0 equivalents) were added to an excess of meta-xylene diamine (MXDA) at 100 ° C. The mixture was maintained at 100 ° C for five hours; then the toluene was removed and the excess MXDA was recovered. The product had an amine equivalent weight of 155.

Step 2: the product of step 1 (229.5 grams, 1. 48 equivalents) and 50 grams (0.0105 equivalents) of an alpha- (2-carboxymethyl) -omega-methoxy-poly (oxy-1,2-ethanediyl) (methoxypolyethylene glycol acid) of equivalent weight of 4762 were reacted at 200 ° C under a nitrogen atmosphere for four hours. The product was cooled to 100 ° C; then, 220.5 grams (1.47 equivalents) of phenylglycidyl ether were added at a rate to maintain the temperature below 140 ° C. The temperature was maintained at 100 ° C for two hours after the completion of the addition, after which time the product was isolated. This product had an amine equivalent weight of 359.

Step 3: the curing agent from step 2 (400 grams) and 44.4 grams of toluene were added to a glass reactor and stirred until the mixture was homogeneous at 87-96 ° C. Then water (111.2 grams) was added at 80 ° C, while stirring at a constant rate of 200 RPM. At the end of the addition, the mixture was inverted to an oil-in-water emulsion. After stirring for one hour at 75 ° C, a second portion (26.2 grams) of toluene was added, followed by 187.6 grams of water. The resulting emulsion, approximately 50% solids, had a viscosity of 7240 cp and an average particle size number of 0.431 microns.

Example 2 The same procedure used in Example 1 was used to prepare this composition. 285.0 grams of EPON Resin 828 / reaction product of MXDA was used to react with 24.0 grams of methoxypolyethylene glycol acid of molecular weight equal to 5000 and then was capped with 91.0 grams of phenylglycidyl ether. After dispersing in the water, it was determined that the particle size of the emulsion was 0.53 microns.

Example 3 The same procedure used in Example 1 was used to prepare this composition. 405.0 grams of EPON Resin HPT-1050 / reaction product of DYTEK A were used to react with 400 grams of methoxypolyethylene glycol acid of molecular weight equal to 5000 and then crowned with 173 grams of HELOXI 62. After dispersing in the water, it was determined that the particle size of the emulsion was 0.49 microns.

Examples 4-1Q For Example 6, the following procedure was used to give a curing agent composition of the invention.

Scheme the This example illustrates the synthesis of a self-emulsifiable floating curing agent composition containing an active surfactant therein. In the first stage, an isolated amine adduct based on a resin solution is made (EPON Resin 828-X-90) and an aliphatic amine (DYTEK A) and subsequently this product is reacted with a polyalkylene glycol terminated in acid and subsequently reacted with a monoglycidyl ether (HELOXY Modifier 62). Then this amine adduct is dispersed in water.

Detailed procedure A four-neck round bottom glass flask was equipped with a condenser having a water trap, a nitrogen inlet, a resin solution inlet and the amine inlet. The flask is flushed with nitrogen.

The amine. { DYTEK A) (356.94 grams) was charged to the reactor and heated to 93 ° C. At 93 ° C a measured addition of the resin solution (212.48 grams) to the amine was started, in such proportion that the temperature of the reaction mixture did not exceed 121 ° C.

After the completion of the addition, the mixture was maintained at 93 ° C for an additional 60 minutes. Diamine and xylene were distilled in excess at about 140 ° C under about 1.5 mmHg. The reaction product had an amine value of approximately 340.94 mg KOH / g (theoretical calculated value is 361.6 mg KOH / g).

Subsequently, the reaction mixture was cooled to 121 ° C and 39.38 grams of surfactant (in solid form), which represents a final surfactant level of about 8% solids by weight of the resin, was charged into the flask and heated to about 200 ° C for 2 hours. The acid value of the reaction mixture was measured after 2 hours of reaction and a value of 2.29 mg KOH / g was found, indicating that the reaction was complete.

Subsequently, the reaction mixture was cooled to 93 ° C, after which 179.5 grams of HELOXY 62, representing approximately 1 equivalent, were added to the reaction vessel at a rate such that the maximum temperature did not exceed 121 ° C.

After the completion of the addition, the reaction was maintained at 93 ° C for 60 minutes. The reaction mixture was allowed to cool to about 78 ° C. Water was added dropwise until the reaction mixture was inverted from a water-in-oil emulsion to an oil-in-water emulsion. The investment was presented at approximately 72% solids content and a temperature of 50 ° C. In addition, water was added to a total amount of 529.16 grams to obtain a final solids content of 50% by weight. The average particle size was 0. 3 μ.

The additional properties of this product are given in Table 3 below.

For Examples 4, 5, 7, 8, 9 and 10, a similar process was used as in Example 6.

In Tables 1 and 2, the different resins, amines and polyalkylene glycols terminated in acid that were used are listed together with the exact amounts that were used during the preparation.

The properties of the different final products are listed in table 3 and 4.

The following methods based on the ASTM code were used for the corresponding tests: ASTM Test or Method Viscosity, viscosity of Brookfield D 2196 Viscosity of application, Stormer Krebs D 562 Hardness of Film, hardness of pencil D 3363 Content of Solids D 2369 Specular Brightness Clear Films D 1308 Pigmented Systems D 4540 Proportion of curing, drying time D 1640 Brightness / time to harden inside container D 1308 Film thickness D 499D Measured with a film Positector 6000 Thickness gauge Impact resistance D 2794-84 Flexibility, conical mandrel D 522 Hegman, grinding fineness. D 1210-79 Acid value D 1639 Adhesion, cut X D 3359 Chemical resistance (24 hour stain test) D 1308 Particle Size The particle size determination of the emulsion and dispersion was determined with a BROOKHAVEN Bi-DCP Particle Meter from Brookhaven Instruments Corporation. Dn is the average particle size number and Dw is the mass of the average particle size. All particle size data were reported in microns, m. Unless otherwise indicated, the particle sizes cited for the dispersions herein are reported as Dn, average particle size number.

Weight for Epoxide The weight per epoxide (WPE or EEEW) of all the products was determined by drying a heavy amount of sample by azeotropic distillation with methylene chloride, then titrating the residue by known methods and correcting the percent solids to determine the WPE at 100% of solids content.

Amine value Defined as the milligrams of KOH equivalent to the basic nitrogen content of a one gram sample, determined by acid-base titration.

Equivalent Weight of Amine It is defined as the weight required to react with an epoxide equivalent weight and is determined from the amine nitrogen content in the known Shell Test Method HC-715-88 (which is comparable to ASTM code D2074-66). ), and the known stoichiometry of the reactants in the resulting product containing nitrogens with hydrogens that will react with epoxides under ambient conditions.

TABLE 1 *: 1 = Methoxypolyethylene glycol acid of about 5000 molecular weight (weight average) (monofunctional) *: 2 = Polyethylene glycol acid from polyethylene glycol diol of about 4600 molecular weight (weight average) TABLE 2 *: 1 = Methoxypolyethylene glycol acid of about 5000 molecular weight (weight average) (monofunctional) **: 2 = Polyethylene glycol acid from polyethylene glycol diol of about 4600 molecular weight (weight average) TABLE 3 TABLE 4 Example 11 Step 1: A solution of 85.7 grams of toluene and EPON Resin 1001 (200.0 grams) were added to an excess of triethylene tetramine (TETA) (220.0 grams) at 100 ° C. The mixture was maintained at 100 ° C for five hours; then the toluene was removed and the excess of TETA was recovered. The product had an amine equivalent weight of 316. The resulting amine adduct was reacted with 88.6 grams of CARDURA Resin E-10 at 130 ° C and then 21.7 grams of Polyethylene glycol acid with a molecular weight of 4600 to 200 ° C. C. After cooling, water was added at 80 ° C to make an oil-in-water emulsion. The resulting emulsion, approximately 45% solids, had an average particle size number of 0.18 microns.

Example 12 This product was made according to the procedure and composition of Example 11 to the extent of crowning the amine adduct with CARDURA Resin E-10 at the end. At this point, the amine adduct crowned at the end was amidified with Polyethylene Glycol Acid of molecular weight equal to 4600 to produce the curing agent product and then the resulting product was thinned with deionized water. The final product was completely soluble in water and was still very viscous at 45% non-volatile compounds in water.

Example 13 and 14 For Example 14, the following procedure was used to give a curing agent composition of the invention.

Scheme IB This example illustrates the synthesis of a self-emulsifiable floating curing agent composition containing an active surfactant in the core. In the first step, an isolated amine adduct based on a resin solution (EPON 1001-X-75) and an aliphatic amine (TETA) is made and subsequently end-capped with a monofunctional glycidyl ether (HELOXY 62).

Then this amine adduct crowned at the end is reacted with an acid-terminated polyalkylene glycol (aqueous solution), which was dissolved in water at a solids content of 60 or 50% by weight.

Then this amine adduct is dispersed in water.

Detailed procedure A four-neck round bottom glass flask was equipped with a condenser having a water trap, a nitrogen inlet, a resin solution inlet and the amine inlet. The flask was flushed with nitrogen.

The amine (TETA) (852.01 grams) was charged to the reactor and heated to 93 ° C. At 93 ° C a measured addition of the resin solution (1217.89 grams) to the amine was started, in such proportion that the temperature of the reaction mixture did not exceed 121 ° C.

After the completion of the addition, the mixture was maintained at 93 ° C for an additional 60 minutes. The diamine and xylene were distilled in excess at about 140 ° C under about 1.5 mmHg. The reaction product had an amine value of approximately 320.3 mg KOH / g.

Subsequently, the reaction mixture was cooled to 80 ° C after which 330.1 grams of HELOXY 62, representing approximately 1.81 equivalents, were added to the reaction vessel at a rate such that the maximum temperature did not exceed 121 ° C.

After the completion of the addition, the reaction was maintained at 93 ° C for 60 minutes.

The reaction mixture was cooled to 80 ° C and the aqueous surfactant (No. 2-81.14 grams) was added rapidly. Subsequently, the reaction mixture was heated to approximately 200 ° C and maintained for 2 hours to react the surfactant and to remove water from the condensation. The acid value of the reaction mixture was measured after two hours of reaction and a value of 1.3 mg KOH / g was found, indicating that the reaction was complete.

The reaction mixture was allowed to cool to about 80 ° C. Water was added dropwise until the reaction mixture was inverted from a water-in-oil emulsion to an oil-in-water emulsion. The investment was presented at approximately 70% solids and a temperature of 77 ° C. In addition, water was added to a total amount of 1518.85 grams to obtain a final solids content of 50% by weight. The average particle size was 0.?, Μ.

The additional properties of this product are given in Table 6 below.

Example 13 was carried out in a similar manner, except that the starting materials and amounts were used as indicated in Table 5 below.

TABLE 5 *: 1 = Methoxypolyethylene glycol acid of about 5000 molecular weight (weight average) (monofunctional) **: 2 = Polyethylene glycol acid from Polyethylene glycol diol of about 4600 molecular weight (weight average) TABLE 6 Clear lacquer data with commercially available epoxy resin dispersions The aforementioned curing agents of the invention can be easily mixed with any commercially available epoxy dispersion and can be applied as coatings. A summary of the properties of two curing agents of the invention (Example 6 and 7) cured with epoxy resin dispersion EPIREZ Waterborne Resin 5522 or 3520 is given in Table 7 below.

TABLE 7 TABLE 7 (Continued) TABLE 7 (Continued) in oo TABLE 7 (Continued) Preparation of aqueous Epoxidic Dispersion To a two-liter resin flask adapted with a stirrer and automatic temperature control, 90.91 g of 7ARC0S0LV PE (propylene glycol monoethylether from Arco Chemical Co.; ARCOSOLV is a trademark), 50.47 g of EPON were added in order. Resin 828, 563.75 grams of EPON Resin 1001 formed in flakes and 15.03 grams of epoxy diluent CARDURA E-10.

This batch was heated slowly to 120 ° C for 45 minutes and then the agitator was started. Then the batch was allowed to cool to 100 ° C. After the whole EPON Resin 1001 dissolved, 40.0 grams of amidoamine surfactant (prepared from DYKTEK A amine and a partially carboxylated polyethylene glycol 4600) and 26.7 grams of deionized water were added to the batch. Then the batch was allowed to cool to 93 ° C for 20 minutes. Then, 81.6 grams of deionized water were added for 1 minute, during which time the temperature was allowed to drop to 87 ° C. At this point, the batch must be inverted to form a resin in water emulsion. The batch was kept for 12 hours at 65-34 ° C. The batch was then diluted to a viscosity of 1.840 cP to 58.8% NV with deionized water for 1 hour and 40 minutes. The particle size of this dispersion was Dn of 0.741 average and Dw of 1.271 microns average.

Paint Formulation: White TiO enamel of curing agent of Example 6 and experimental epoxy dispersion A This paint was first prepared by making a titanium dioxide pigment paste in water using a commercial dispersant, DISPERBYK 190 by BYK Chemie, 0.3% based on the weight of the pigment. This pigment paste was added to the epoxy dispersion prepared above in an amount to obtain a pigment to resin filler of 0.8 to 1.0 together with an appropriate amount of the propylene glycol phenyl ether and allowed to deaerate overnight (8% by weight of the epoxy dispersion). On the next day, the curing agent of Example 6 and the pigmented epoxy dispersion were combined in a ratio of hydrogen to epoxy one by one and after about 30 minutes, the resulting paint was applied by spraying to steel laminated test panels in cold treated with iron phosphate. After one month of curing at 77 degrees F and 50% relative humidity, the following properties of the paint were measured.

From the above results, where a dispersion of experimental curing agent has been pigmented and mixed with a dispersion of experimental epoxy resin, and subsequently compared to a commercially available floating formulation of which the preparation of the paint was exactly similar, the Following conclusions can be drawn: the new experimental system is at least comparable in operation and even exceeds the commercial system in flexibility, chemical resistance and brightness value. In addition to this excellent performance, the advantage for the experimental system is its very low volatile organic compound content: a value of approximately 100 grams / Liter or 1.0 pounds / gallon compared to 240 grams / Liter or 2 pounds / gallon for systems commercial.

Coating agents based on aliphatics are usually hydrophobic in character, which tend to improve the coalescence properties of the epoxy curing agent mixture at low temperatures, and tend to lower the glass transition temperature of the film or coating. The lower glass transition temperature improves the impact resistance of the cured film. However, the aromatic based monoglycidyl crowning agents have the advantage of stiffening the curing film, chemically resistant, and resistant to stresses at high temperatures. Any of these types of capping agents can be used, and mixtures thereof are also advantageous to achieve an overall balance of mechanical strength and chemical resistance.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Having described the invention as above, the content of the following is claimed as property.

Claims (12)

1. A curing agent for epoxy resins, characterized in that it comprises a reaction product prepared by the steps comprising (a) reacting at least one polyamine having at least 3 active amine hydrogen atoms per molecule and at least one epoxy resin having a functionality of at least 1.5 at a mole ratio of epoxy to polyamine functionality equivalents of 0.9 : 1 to 1:10, whereby an intermediate product finished in amine is produced; (b) reacting the finished intermediate product in amine with 0.5 to 25 weight percent, based on the amine-terminated intermediate, of a polyalkylene glycol-containing compound terminated in acid having the formula: (II) (III) wherein R1 is an alkyl, aryl, or arylalkyl group having 1 to 15 carbon atoms, X and Y are independently a hydrogen, methyl or ethyl group with the proviso that if X is methyl or ethyl, Y is hydrogen or Y is is methyl or ethyl, X is hydrogen, and n + m + o is a real number from 100 to 200, and n + o is at least 70 percent of n + m + o, in a ratio of (I) to (II) by weight in the range of 100: 0 to 0: 100, a ratio of (I) to (III) by weight in the range of 100: 0 to 0: 100, and in a proportion of (II) to (III) by weight in the range of 100: 0 to 0: 100, until essentially the entire acid group is consumed, thereby producing the curing agent finished in amine.

2. The curing agent according to claim 1, characterized in that it also comprises the steps of: (c) reacting the amine-terminated curing agent with a monoepoxy at a ratio of amine hydrogen atoms to epoxy groups of 1.5: 1 to 30: 1.

3. The curing agent according to claims 1 and 2, characterized in that the amine-terminated curing agent is prepared by reacting the acid-terminated polyalkylene glycol-containing compound of structures (I), (II) and (III) in an amount from 4 to 98 percent by weight of (I), 1 to 95 percent by weight of (II), 1 to 95 percent by weight of (III) and the finished product in amine.

4. The curing agent according to claim 2, characterized in that the amine-terminated curing agent is reacted with a monoepoxy at a ratio of amine hydrogen atoms to epoxy groups from 2: 1 to 20: 1.

5. The curing agent according to claim 4, characterized in that the amine-terminated curing agent is reacted with a monoepoxy at a ratio of amine hydrogen atoms to epoxy groups from 2: 1 to 10: 1.

6. The curing agent according to claims 1-5, characterized in that m is 0.

7. The curing agent according to claims 1 and 2, characterized in that the polyamine has the formula: H2H -NH? wherein R is an aliphatic, cycloaliphatic, or aromatic group having 2 to 18 carbon atoms, optionally containing unreactive oxygen or at most an average of 4 secondary and / or tertiary nitrogen atoms per molecule in the main structure.

8. The curing agent according to claims 1-7, characterized in that the curing agent is prepared by reacting a polyalkylene glycol alkyl ether finished in acid having the formula Or I -o- -CH2-CH2-O-} c-CH2- -0H wherein R1 is an alkyl, aryl, or arylalkyl group having 1 to 15 carbon atoms, or is a positive real number from 100 to 200, and at least one diamine in an amine to acid equivalent ratio of 6: 1 up to 25: 1.

9. The curing agent according to claims 1-8, characterized in that the polyalkylene glycol alkyl ether terminated in acid is prepared by reacting a compound containing polyalkylene glycol terminated in acid having the formula wherein R1 is an alkyl or arylalkyl group having 1 to 15 carbon atoms, or is a positive real number from 100 to 200, and at least one intermediate compound amine terminated at a ratio of amine to acid equivalent of 6: 1 up 25: 1.

10. A composition, characterized in that it comprises (a) water; and (b) curing agent according to claims 1-9.

11. An aqueous curable epoxy resin system, characterized in that it comprises: (a) water, (b) at least one epoxy resin; and (c) curing agent according to the claims 1-9.

12. A cured composition according to claim 11. SUMMARY OF THE INVENTION The present invention relates to a curing agent compatible with water for epoxy resins. The curing agent can be made by (a) reacting at least one polyamine having at least 3 hydrogen atoms of active amine per molecule and at least one epoxy resin having a functionality of at least 1.5 in a mole ratio of equivalents of epoxy to polyamine functionality from 0.9: 1 to 1:10, whereby an amine-terminated intermediate is produced; (b) by reacting the amine-terminated intermediate product with 0.5 to 25 weight percent, based on the amine-terminated intermediate, of an acid-terminated polyalkylene glycol-containing compound having the formulas (I), (II) and (III), wherein R1 is an alkyl, aryl, or arylalkyl group having 1 to 15 carbon atoms, X and Y are independently a hydrogen, methyl, or ethyl group with the proviso that X is methyl or ethyl, and is hydrogen or yes Y is methyl or ethyl, X is hydrogen, and n + m + o is a real number from 100 to 200, and n + o is at least 70 percent of n + m + o, and in a proportion of ( I) a (II) by weight in the range of 100: 0 to 0: 100, and in a proportion of (I) to (III) by weight in the range of 100: 0 to 0: 100, and in a ratio of (II) to (III) by weight in the range of 100: 0 to 0: 100, until essentially all of the - The acid group. Such an amine-terminated curing agent can also be crowned with a monoepoxy. The curing agent can also be prepared by (a) reacting at least one polyamine described above and an epoxy resin, whereby an amine-terminated intermediate product is produced; (b) reacting the amine-terminated intermediate with mono-epoxy to give a finished product in a crowned amine; then (s) by reacting the capped amine intermediate with a polyalkylene glycol-containing compound terminated in acid described above.