Monoalkylated diamines for epoxy formulations: Novel curing agents for epoxy systems.

Abstract

To provide an epoxy resin system and a method for producing the epoxy resin system, capable of solving drawbacks of the prior art techniques.SOLUTION: An epoxy resin system can contain an epoxy resin and a monoalkylated diamine. The epoxy resin system can further contain a second amine. A method for producing an epoxy resin system comprises combining an epoxy resin with a monoalkylated diamine.EFFECT: The monoalkylated diamines of this invention enhance desirable processing and cured properties of epoxy resin compositions without the negative impact on mechanical properties in the cured product normally seen with cycloaliphatic amine-based curing agents.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an epoxy resin system comprising an epoxy resin and a mono-alkylated diamine. The epoxy resin system may further comprise a second amine. The present invention also relates to a method of producing the epoxy resin system, comprising combining an epoxy resin with the mono-alkylated diamine. The mono-alkylated diamine of the present invention enhances desirable processing and cured product properties of epoxy resin compositions without adversely affecting the mechanical properties of the cured product, as typically observed with cycloaliphatic amine-based curing agents. [Background technology]

[0002] Aromatic and cycloaliphatic amines are commonly used as epoxy curing agents for thermoset structural composite applications. The type of amine used as a curing agent is essential to achieving the final performance of the cured product. Each reactive amine type, primary or secondary, is cured at a specific temperature to achieve full cure. The cure temperature defines the end-use temperature, and the T g Typically, compounding epoxy resins with high-functionality hardeners leads to short working life, high compound viscosity, and weak spots after curing. All of these adverse effects are caused by the high functionality of the hardener. In step-growth polymerization, the degree of polymerization X n , and the critical progress of the reaction (gel point - p c ) is directly linked to the functionality of the polymerization system: X n =2 / (2-pf ave ) is well known, where p is the progress of the reaction, and f ave is the average functionality, and p c =2 / f ave Therefore, systems with higher average functionality will reach high molecular weights and gels at a lower degree of polymerization than those with lower average functionality. U.S. Pat. No. 4,293,682 discloses the use of tetra- and penta-functional amines as curing agents.

[0003] While low-functionality curing agents provide longer pot life, they also result in a final cured network with low crosslink density and poor thermal and mechanical properties. This inverse relationship between high-functionality monomers required for final part properties and low-functionality monomers for increased pot life requires compromises in epoxy resin formulations. Some low-functionality materials do not build robust polymer networks for use in structural applications. Anything that can be done to increase pot life without adversely affecting final part properties would be advantageous. Some low-functionality materials do not build robust polymer networks for use in structural applications.

[0004] Epoxy resin systems are used in the manufacture of a variety of structural parts, including composites. Examples of articles that have been evaluated for fabrication from epoxy resin systems include composite pipes, pressure vessels, automotive parts, and wind turbine blades. Fabrication of such parts involves numerous requirements for efficient production, especially when complex manufacturing processes are used. These processes include, but are not limited to, resin infusion, resin transfer molding, filament winding, and large-scale casting. One need in the art is a relatively long pot life for the epoxy resin system to wet fibers in relatively thick sections of the article, where the fabric layer is very dense under vacuum or pressure and the resin cannot easily penetrate the fabric layer. If the temperature increases during processing of the article, the viscosity of the cycloaliphatic amine increases under these conditions, making fiber wetting difficult and resulting in a loss of mechanical properties in the fabricated part.

[0005] Additionally, the early increase in viscosity during processing can lead to higher shrinkage of the molded part after curing. The shrinkage of the cured epoxy resin causes stresses to build up in the composite due to the increased viscosity during processing. The stresses can sometimes lead to delamination in the article, resulting in a loss of mechanical properties. The relatively short pot life of the formulation causes the viscosity to increase relatively quickly during processing of longer parts, and a relatively large amount of stress to build up in the article during processing.

[0006] For advanced composites to achieve higher performance, multifunctional resins and curing agents are often used. The multifunctional materials usually have a very high starting viscosity. Heat is commonly used to reduce the compound viscosity. This approach increases the reactivity and can therefore cause handling problems. As the composite parts become larger and thicker, the compound viscosity needs to be lower to have optimal wetting of the reinforcing materials (e.g., glass, carbon, Kevlar, natural fibers, etc.).

[0007] Systems for composite processing require a sufficiently low initial mix viscosity and a sufficiently low rate of viscosity increase at the impregnation temperature so that the resin can completely wet out the reinforcing fiber preform before the resin system becomes too viscous to flow satisfactorily through the substrate fibers and fabrics. The requirements for low initial viscosity and long pot life become more stringent as the size of the composite parts increases.

[0008] In view of the above, there is a need in the art for improved curing agents to produce epoxy resin systems that have a longer pot life "work time" of the formulation, thereby reducing make-up materials during processing, and when combined with improved fiber wetting, enhance mechanical properties compared to prior art resin compositions.

[0009] The dialkylation of isophoronediamine (IPD) is known in the literature (U.S. Pat. No. 7,074,963 B2). The monoalkylated structure of IPD is an intermediate for the dialkylated IPD product. The final compositions of dialkylated IPD reported in U.S. Pat. Nos. 6,403,752 B1 and 7,074,963 are completely devoid of monoalkylated IPD. In the present invention, monoalkylated IPD and other monoalkylated cycloaliphatic diamines are used as epoxy curing agents to extend the pot life of IPD, which is not found in any prior art. In addition, the isomer type of the monoalkylated IPD product in the present invention is different from the monoalkylated IPD proposed to produce the dialkylated product in U.S. Pat. No. 7,074,963 B2. The unalkylated (unmodified) IPD exhibits a higher Tg and a shorter pot life. The dialkylated IPD products do not progress to full cure with the epoxy resin. The present approach using monoalkylated IPD and other monoalkylated cycloaliphatic diamines provides an excellent balance of pot life while maintaining their high Tg. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] U.S. Patent No. 4,293,682 [Patent Document 2] U.S. Patent No. 7,074,963 [Patent Document 3] U.S. Patent No. 6,403,752 [Patent Document 4] International Publication No. 2009 / 089145 [Patent Document 5] U.S. Patent No. 2,890,194 [Non-patent literature]

[0011] [Non-Patent Document 1] Y. Tanaka, “Synthesis and Characteristics of Epoxides”, CA May, ed., Epoxy Resins Chemistry and Technology (Marcel Dekker, 1988). Summary of the Invention [Problem to be solved by the invention]

[0012] The object of the present invention was to provide an epoxy resin system and a curing agent that overcome the above-mentioned drawbacks of the prior art, as well as a method for producing the same. [Means for solving the problem]

[0013] The above object has been achieved by the epoxy resin system and hardener as well as the process for producing the same according to the claims.

[0014] Summary of the Invention It has been discovered that monoalkylated araliphatic and cycloaliphatic diamines can be used as primary curing agents for epoxy resin compositions, providing sufficient pot life during processing (in the resin bath and fiber wetting) compared to typical cycloaliphatic amine-based curing agents, resulting in overall improved mechanical properties of cured composite products. A major drawback of using cycloaliphatic amines is their short pot life. Another way to measure pot life commercially is the time it takes for the formulation viscosity to double. This provides a good measure of the system's pot life. By using monoalkylated cycloaliphatic diamines as primary curing agents, it is possible to achieve twice the pot life of the cycloaliphatic diamines and achieve full cure at significantly lower temperatures than current cycloaliphatic amine curing agents. Test results show that using monoalkylated cycloaliphatic diamines as primary curing agents maintains good mechanical, thermal, and chemical performance in the cured epoxy compositions and exceeds the mechanical properties of other cycloaliphatic amines. Additionally, formulations containing monoalkylated cycloaliphatic diamines exhibit lower viscosity, longer pot life, and lower temperature T compared to epoxy compositions cured with current cycloaliphatic amine curing agents. g They exhibit lower exotherms during development and cure. Monoalkylated cycloaliphatic diamines can also be used in combination with primary and secondary amines as co-curing agents to further enhance desired properties. The lower viscosity of monoalkylated cycloaliphatic diamines aids in fiber wetting. Preliminary results using monoalkylated cycloaliphatic diamines in composite applications (filament wound tubing and fittings, wind blades, high pressure vessels, structural laminates, automotive body parts, aerospace, etc.) are quite promising.

[0015] An embodiment of the present invention is a composition comprising an epoxy resin and a copolymer of formula (I) [ka] [Wherein Z is cyclohexyl, C1-C 10 Alkyl-substituted cyclohexyl, phenyl, C1-C 10Alkyl-substituted phenyl, methylenebis(cyclohexyl), and C1-C 10 alkyl-substituted methylenebis(cyclohexyl), a and b are independently 0 or 1, and A is selected from the group consisting of C1-C 10 and a monoalkylated diamine, wherein the monoalkylated diamine comprises a monoalkylated cycloaliphatic diamine or a monoalkylated araliphatic diamine selected from monoalkylated IPD, monoalkylated PACM, monoalkylated DMPACM, monoalkylated MXDA, monoalkylated cyclohexyldiamine, and monoalkylated methylcyclohexyldiamine.

[0016] FIG. 1 shows the viscosity profiles at 40° C. for an epoxy resin composition containing isophorone diamine (IPD) and an epoxy resin composition containing monoalkylated isophorone diamine (AIPD). [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 shows the viscosity profiles at 40° C. for an epoxy resin composition containing non-alkylated IPD and an epoxy resin composition containing mono-alkylated IPD. DETAILED DESCRIPTION OF THE INVENTION

[0018] definition The following definitions and abbreviations are provided to aid those skilled in the art in understanding the detailed description of the present invention. IPD - Isophoronediamine PACM - 4,4'-methylenebis(cyclohexylamine) MXDA - m-xylylenediamine DMPACM - 2,2'-dimethyl-4,4'-methylenebis(cyclohexylamine) Hydrogenated TDA - Methylcyclohexyldiamine CHONE - Cyclohexanone MEK - Methyl ethyl ketone ISO—Isophorone.

[0019] Detailed Description of the Invention The epoxy resin system of the present invention comprises an epoxy resin and a copolymer of formula (I) [ka] [Wherein Z is cyclohexyl, C1-C 10 Alkyl-substituted cyclohexyl, phenyl, C1-C 10 Alkyl-substituted phenyl, methylenebis(cyclohexyl), and C1-C 10 alkyl-substituted methylenebis(cyclohexyl), a and b are independently 0 or 1, and Y is selected from the group consisting of C1-C 10 and monoalkylated diamines in which the alkyl is alkyl.

[0020] The monoalkylated diamines can be preferably obtained by reacting the corresponding diamines with acetone, methyl ethyl ketone, cyclohexanone, isophorone or aliphatic aldehydes, such as acetaldehyde, followed by hydrogenation, or by reacting the diamines with alkyl halides. Thus, Y can preferably be a cyclohexyl group, a sec-butyl group, a trimethylcyclohexyl group, or an isopropyl group, derived from the respective ketone, aldehyde, and alkyl halide.

[0021] In one preferred embodiment of the present invention, the monoalkylated diamine has the structure: [ka] wherein each of R1, R2, R3, R4, R5, and R6 is H, CH3, or a C2-C4 alkyl group; n is 0 or 1; A is H; and B is a C1-C4 alkyl group. 10 alkyl, or B is H and A is C1-C 10The monoalkylated diamine can be preferably obtained by reacting the diamine with acetone, methyl ethyl ketone, cyclohexanone, isophorone or an aliphatic aldehyde, such as acetaldehyde, followed by hydrogenation, or by reacting the diamine with an alkyl halide. Thus, A or B may preferably be a cyclohexyl group, a sec-butyl group, a trimethylcyclohexyl group, or an isopropyl group, derived from the respective ketone, aldehyde, and alkyl halide.

[0022] In a preferred embodiment of structure (II), the monoalkylated diamine has the structure: [ka] [Wherein A is C1 to C 10 monoalkylated isophorone diamine represented by the formula: structure: [ka] [Wherein B is C1 to C 10 monoalkylated isophorone diamine represented by the formula: structure: [ka] [Wherein A is C1 to C 10 monoalkylated methylcyclohexyldiamine represented by the formula: structure: [ka] [Wherein B is C1 to C 10 monoalkylated methylcyclohexyldiamines represented by the formula: structure: [ka] [Wherein A is C1 to C 10a monoalkylated cyclohexyldiamine represented by the formula is selected from the group consisting of:

[0023] In another preferred embodiment of the present invention, the monoalkylated diamine has the structure: [ka] wherein each of R1 and R2 is H or CH3, and A is C1 to C 10 The monoalkylated diamine is preferably obtained by reacting the diamine with acetone, methyl ethyl ketone, cyclohexanone, isophorone or an aliphatic aldehyde, such as acetaldehyde, followed by hydrogenation, or by reacting the diamine with an alkyl halide. Accordingly, A is preferably a cyclohexyl group, a sec-butyl group, a trimethylcyclohexyl group, or an isopropyl group, derived from the respective ketone, aldehyde, and alkyl halide.

[0024] In a further preferred embodiment of structure (VIII), the monoalkylated diamine has the structure: [ka] [Wherein A is C1 to C 10 monoalkylated 4,4'-methylenebis(cyclohexylamine), wherein the alkyl is an alkyl; and structure: [ka] [Wherein A is C1 to C 10 Monoalkylated 2,2'-dimethyl-4,4'-methylenebis(cyclohexylamine) represented by the formula is selected from the group consisting of:

[0025] In another preferred embodiment of the present invention, the monoalkylated diamine has the structure: [ka] [Wherein X is a phenyl group or a cyclohexyl group, and A is a C1-C 10 The monoalkylated diamine can be preferably obtained by reacting the diamine with acetone, methyl ethyl ketone, cyclohexanone, isophorone or an aliphatic aldehyde, such as acetaldehyde, followed by hydrogenation, or by reacting the diamine with an alkyl halide. Accordingly, A may preferably be a cyclohexyl group, a sec-butyl group, a trimethylcyclohexyl group, or an isopropyl group, derived from the respective ketone, aldehyde, and alkyl halide.

[0026] In one preferred embodiment of structure (XI), the monoalkylated diamine has the structure: [ka] [Wherein A is C1 to C 10 monoalkylated m-xylylenediamine represented by the formula: structure: [ka] [Wherein A is C1 to C 10 Monoalkylated 1,3-bisaminomethylcyclohexane represented by the formula: is selected from the group consisting of:

[0027] The epoxy resin system may contain one or more epoxy resins. Preferably, the epoxy resin system contains only one epoxy resin. Similarly, the epoxy resin system may contain one or more compounds of formula (I). Preferably, the epoxy resin system contains only one compound of formula (I).

[0028] In one embodiment, the epoxy resin system comprises 1% to 99% by weight of the monoalkylated diamine, based on the total weight of the curing agent. Preferably, the epoxy resin system comprises at least 20%, more preferably at least 40%, even more preferably at least 60%, and particularly preferably at least 80% by weight of the monoalkylated diamine, based on the total weight of the curing agent.

[0029] Preferably, the epoxy resin system comprises 20 to 100% by weight of the monoalkylated diamine, 0 to 50% by weight of the non-alkylated diamine, and 0 to 30% by weight of the dialkylated diamine, based on the total weight of the curing agent.

[0030] Another aspect of the present invention is a method for producing an epoxy resin system, said method comprising: [ka] wherein Z is selected from the group consisting of cyclohexyl, C1-C4 alkyl-substituted cyclohexyl, phenyl, C1-C4 alkyl-substituted phenyl, methylenebis(cyclohexyl), and C1-C4 alkyl-substituted methylenebis(cyclohexyl); a and b are independently 0 or 1; and Y is C1-C 10 The method includes combining a monoalkylated diamine of the formula (I) with an alkyl group, and optionally other ingredients.

[0031] The mass ratio of the epoxy resin to the monoalkylated diamine is preferably 1:0.05 to 1:0.95, and in a more preferred embodiment, the mass ratio is 1:0.3 to 1:0.6.

[0032] The epoxy resin system may further preferably include a second amine selected from the group consisting of primary amines and secondary amines. The second amine preferably includes one or more amine compounds selected from the group consisting of polyetheramines, polyetherpolyamines, saturated aliphatic cyclic diamines, linear aliphatic amines, cycloaliphatic amines, polycyclic aliphatic amines, and aromatic amines.

[0033] Preferably, the polyetheramine has the formula: HNCH(CH)CH—[OCHCH(CH)] x NH2, and x is 2 to 70. Preferably, the second amine is 4,4'-methylenebiscyclohexylamine, isophoronediamine, 1,2-diaminocyclohexane, 4,4'-methylenebis(2-methylcyclohexylamine), 1,3-bisaminomethylcyclohexane, and polyetheramine: H2NCH(CH3)CH2[OCH2CH(CH3)] 2.5 NH2 mixtures.

[0034] Preferably, modified amine compounds, such as Mannich bases, polyamide compounds, amine-epoxy adducts, and combinations thereof, can be used as co-curing agents for use with mono-alkylated diamine compounds as described herein.

[0035] Preferably, the epoxy resin may comprise a polyglycidyl ether of a compound selected from the group consisting of an aliphatic glycol, a cycloaliphatic glycol, a triol, a polyol, a polyglycol, and combinations thereof. The epoxy resin system may further comprise a polyacrylate or polymethacrylate ester of a polyol.

[0036] Referring to Figure 1, the viscosity profile at 40°C for an epoxy resin composition containing the non-alkylated product (IPD) is compared to the viscosity profile for an epoxy resin composition containing the mono-alkylated product. The reactivity time (minutes) of the composition increases significantly with alkylation chemistry.

[0037] The epoxy resin may consist of a single resin or may be a mixture of mutually compatible epoxy resins. The epoxy resin may include, but is not limited to, difunctional epoxy resins, such as bisphenol-A and bisphenol-F resins. As used herein, a multifunctional epoxy resin refers to a compound having two or more 1,2-epoxy groups per molecule. Epoxide compounds of this type are well known to those skilled in the art and are described in Y. Tanaka, "Synthesis and Characteristics of Epoxides," CA May, ed., Epoxy Resins Chemistry and Technology (Marcel Dekker, 1988), which is incorporated herein by reference in its entirety.

[0038] One type of epoxy resin suitable for use is the glycidyl ethers of polyhydric phenols, including glycidyl ethers of dihydric phenols. Preferred are the glycidyl ethers of the following: resorcinol, hydroquinone, bis-(4-hydroxy-3,5-difluorophenyl)-methane, 1,1-bis-(4-hydroxyphenyl)-ethane, 2,2-bis-(4-hydroxy-3-methylphenyl)-propane, 2,2-bis-(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis-(4-hydroxyphenyl)-propane (commercially known as bisphenol-A), bis-(4-hydroxyphenyl)-methane (commercially known as bisphenol-F, which may contain varying amounts of 2-hydroxyphenyl isomers), and the like, or any combination thereof. Additionally, the advance process dihydric phenol of the structure of formula (XIV) is also preferred in the present disclosure: [ka] [wherein m is 0 to 25, and R is a divalent hydrocarbon radical of a dihydric phenol, for example, a divalent hydrocarbon radical of a dihydric phenol listed above].

[0039] Materials according to formula (1) can be prepared by polymerizing a mixture of a dihydric phenol and epichlorohydrin, or by advancing a mixture of a diglycidyl ether of the dihydric phenol with the dihydric phenol. While the value of m in any particular molecule is an integer, the material is always a mixture that can be characterized by an average value of m, which is not necessarily an integer. Polymeric materials having an average value of m between 0 and about 7 can be used in one embodiment of the present disclosure. In other embodiments, the epoxy resin can be a polyglycidylamine from one or more of 2,2'-methylenedianiline, 4,4'-methylenedianiline, m-xylenedianiline, hydantoin, and isocyanate.

[0040] The epoxy resin may preferably be a cycloaliphatic (alicyclic) epoxide. Particularly preferred cycloaliphatic epoxides are diepoxides of cycloaliphatic esters of dicarboxylic acids, particularly bis(3,4-epoxycyclohexylmethyl)oxalate, bis(3,4-epoxycyclohexylmethyl)adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, vinylcyclohexene diepoxide; limonene diepoxide; bis(3,4-epoxycyclohexylmethyl)pimelate; dicyclopentadiene diepoxide; and other suitable cycloaliphatic epoxides. Suitable other diepoxides of cycloaliphatic esters of dicarboxylic acids are described, for example, in International Publication No. 2009 / 089145 (WO 2009 / 089145 A1), which is hereby incorporated by reference in its entirety.

[0041] Other particularly preferred cycloaliphatic epoxides are 3,3-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate; 3,3-epoxy-1-methylcyclohexyl-methyl-3,4-epoxy-1-methylcyclohexanecarboxylate; 6-methyl-3,4-epoxycyclohexylmethyl-6-methyl-3,4-epoxycyclohexanecarboxylate; and 3,4-epoxy-2-methylcyclohexyl-methyl-3,4-epoxy-3-methylcyclohexanecarboxylate. Other suitable 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylates are described, for example, in U.S. Patent No. 2,890,194, which is hereby incorporated by reference in its entirety. In other embodiments, the epoxy resin may comprise a polyol polyglycidyl ether from polyethylene glycol, polypropylene glycol, or polytetrahydrofuran, or a combination thereof.

[0042] In another embodiment, epoxy novolac resins, which are glycidyl ethers of novolac resins, can be used as multifunctional epoxy resins according to the present disclosure. In yet another embodiment, the at least one multifunctional epoxy resin is a diglycidyl ether of bisphenol-A (DGEBA), an Advance Process variant or higher molecular weight variant of DGEBA, a diglycidyl ether of bisphenol-F, an epoxy novolac resin, or any combination thereof. Higher molecular weight variants or derivatives of DGEBA are prepared by the Advance Process, in which excess DGEBA is reacted with bisphenol-A to produce epoxy-terminated products. The epoxy equivalent weight (EEW) of such products ranges from about 450 to 3000 or more. Because these products are solid at room temperature, they are often referred to as solid epoxy resins.

[0043] DGEBA or advanced process DGEBA resins are often used in structural formulations due to their combination of low cost and high performance properties. Commercial grades of DGEBA with EEWs ranging from about 174 to about 250, and more commonly from about 185 to about 195, are readily available. At these low molecular weights, the epoxy resins are liquid and are often referred to as liquid epoxy resins. Most grades of liquid epoxy resins are understood by those skilled in the art to be slightly polymeric, since pure DGEBA has an EEW of 174. Resins with EEWs of 250 to 450, typically produced by the advanced process, are also referred to as semi-solid epoxy resins, since they are a mixture of solids and liquids at room temperature. Multifunctional resins with an EEW of about 160 to about 750 based on solids are useful in the present disclosure. In another embodiment, the multifunctional epoxy resins have an EEW ranging from about 170 to about 250.

[0044] Depending on the end use application, it may be beneficial to reduce the viscosity of the composition of the present disclosure by modifying the epoxy resin. The epoxy resin, including at least one multifunctional epoxy resin, may further comprise a monofunctional epoxide. Preferred examples of monoepoxides include styrene oxide, cyclohexene oxide, and phenol, cresols, tert-butylphenol, other alkylphenols, butanol, 2-ethylhexanol, C4 to C6. 14 glycidyl ethers of alcohols, etc., or combinations thereof. The multifunctional epoxy resin may be present in a solution or emulsion, where the diluent is water, an organic solvent, or a mixture thereof.

[0045] hardener As described above, the curing agent is a monoalkylated diamine of formula (I). The curing agent may further include a second amine. The second amine may consist of a single amine or a mixture of amines. The amine in the second amine may be a primary or secondary amine.

[0046] In some applications, the following are suitable as the second amine: polyether diamines, saturated aliphatic cyclic diamines, linear aliphatic amines, cycloaliphatic diamines, polycycloaliphatic amines, aromatic amines, and combinations thereof. The weight ratio of the epoxy resin to the monoalkylated diamine and second amine is preferably 1:0.95:0.05. In another embodiment, the weight ratio is preferably 1:0.05:0.95. The polyamine is preferably an aliphatic polyamine, such as diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), pentaethylenehexamine (PEHA), hexamethylenediamine (HMDA), N-(2-aminoethyl)-1,3-propanediamine (N3-amine), N,N'-1,2-ethanediylbis-1,3-propanediamine (N4-amine), or dipropylenetriamine; an arylaliphatic polyamine, such as m-xylylenediamine (mXDA), or p-xylylenediamine; a cycloaliphatic polyamine, such as 1, 3-bisaminomethylcyclohexane (1,3-BAC), isophoronediamine (IPDA), 4,4′-methylenebiscyclohexylamine (PACM), 1,2-diaminocyclohexane, or 4,4′-methylenebis-(2-methyl-cyclohexyl-amine); aromatic polyamines, such as m-phenylenediamine, diaminodiphenylmethane (DDM), or diaminodiphenylsulfone (DDS); heterocyclic polyamines, such as N-aminoethylpiperazine (NAEP), or 3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro(5,5)undecane;Polyalkoxypolyamines in which the alkoxy groups may be oxyethylene, oxypropylene, oxy-1,2-butylene, oxy-1,4-butylene or copolymers thereof, such as 4,7-dioxadecane-1,10-diamine, 1-propanamine, 3,3′-(oxybis(2,1-ethanediyloxy))bis-(diaminopropylated diethylene glycol ANCAMINE® 1922A), poly(oxy(methyl-1,2-ethanediyl)), α-(2-aminomethylethyl)-ω-(2-aminomethylethoxy) (JEFFAMINE® D 230, D-400), triethylene glycol diamine and oligomers (JEFFAMINE® XTJ-504, JEFFAMINE® XTJ-512), poly(oxy(methyl-1,2-ethanediyl)), α,α'-(oxydi-2,1-ethanediyl)bis(ω-(aminomethylethoxy)) (JEFFAMINE® XTJ-511), bis(3-aminopropyl)polytetrahydrofuran 350, bis(3-aminopropyl)polytetrahydrofuran 750, poly(oxy(methyl-1,2-ethanediyl)), α-hydro-ω-(2-aminomethylethoxy)ether and 2-ethyl-2-(hydroxymethyl)-1,3-propanediol (3:1) (JEFFAMINE® T-403), and diaminopropyl dipropylene glycol. JEFFAMINE® is a registered trademark of Huntsman Petrochemical LLC.

[0047] Particularly suitable polyamines are isophoronediamine (IPD), 4,4'-methylenebiscyclohexylamine (PACM), 3,3'-dimethyl PACM (ANCAMINE® 2049), N-aminoethylpiperazine (NAEP), 4,7-dioxadecane-1,10-diamine, 1-propanamine, 3,3'-(oxybis(2,1-ethanediyloxy))bis- (ANCAMINE® 1922A), poly(oxy(methyl-1,2-ethanediyl)), α-(2-aminomethylethyl)-ω-(2-aminomethylethoxy) (JEFFAMINE® D 230, D-400), poly(propylene glycol) bis(2-aminopropyl ether), triethylene glycol diamine (JEFFAMINE® XTJ-504), and poly(oxy(methyl-1,2-ethanediyl)), α,α'-(oxy(di-2,1-ethanediyl))bis(ω-(aminomethylethoxy)) (JEFFAMINE® XTJ-511), or mixtures thereof. ANCAMINE® is a registered trademark of Evonik Degussa GmbH.

[0048] Additional amines suitable for forming the second amine include those having the structure (XV): [ka] wherein R1 is CH2CH2CH2NH2; R2, R3, and R4 are independently H or CH2CH2CH2NH2; and X is CH2CH2 or CH2CH2CH2. In one embodiment, R2 and R3 are not simultaneously H.

[0049] Optional additives The epoxy-based formulation for the composite may optionally contain additives such as, but not limited to, non-reactive plasticizer(s), filler(s), processing aid(s), stabilizers, defoamers, viscosity modifier(s), UV absorbers, flame retardants, and / or impact modifiers.

[0050] Any of the acrylate or methacrylate esters of polyols are blended with the epoxy resin in a weight ratio of from 0 to about 100 parts ester for each 100 parts epoxy resin. In another embodiment, the acrylate or methacrylate esters of polyols are blended with the epoxy resin in a weight ratio of from about 5 to about 100 parts ester for each 100 parts epoxy resin.

[0051] Nanomaterials / fillers may be included. The term "nanomaterial" includes, but is not limited to, multi-walled carbon nanotubes or boron nitride nanotubes, single-walled carbon, carbon or boron nitride nanoparticles, carbon or boron nitride nanofibers, carbon or boron nitride nanoropes, carbon or boron nitride nanoribbons, nanoclays; nanoclays with tubules; layered inorganic clay materials; talc; carbon black; cellulose fibers; silica; and alumina.

[0052] The epoxy resin system of the present invention can preferably be prepared by a method for preparing an epoxy resin system, wherein the epoxy resin is a compound represented by formula (I): [ka] wherein Z is selected from the group consisting of cyclohexyl, C1-C4 alkyl-substituted cyclohexyl, phenyl, C1-C4 alkyl-substituted phenyl, methylenebis(cyclohexyl), and C1-C4 alkyl-substituted methylenebis(cyclohexyl); a and b are independently 0 or 1; and Y is C1-C 10 The diamine is a monoalkylated diamine, and optionally other ingredients.

[0053] The curable epoxy resin compositions and cured products described herein may be useful as structural and electrical laminates, coatings, castings, structural components (particularly for the aerospace industry), and circuit boards for the electronics industry, among other applications. The curable epoxy resin compositions disclosed herein may be used in electrical varnishes, encapsulants, semiconductors, general-purpose molding powders, filament-wound tubing and fittings, filament-wound pressure vessels, low- and high-pressure tubing and fittings, low- and high-pressure vessels, storage tanks, wind turbine blades, automotive structural components, aerospace structural components, oil and gas buoyancy modules, rigs, well plugs, cured-in-place piping (CIPP), structural adhesives and laminates, composite liners, pump liners, corrosion-resistant coatings, and other suitable epoxy-containing products.

[0054] The curable epoxy resin composition may be used to form a composite material based on a reinforcing fiber substrate. The reinforcing fiber substrate may preferably be one or more layers of fiberglass material. Contacting the reinforcing fiber substrate with the epoxy resin system may preferably include a coating process selected from the group consisting of hand lamination, infusion process, filament winding, pultrusion, resin transfer molding, fiber pre-impregnation process, and combinations thereof.

[0055] Preferred fibrous substrates include organic or inorganic fibers, natural or synthetic fibers, and may be in the form of woven or non-crimp fabrics, nonwovens, webs or mats, as well as fiber strands (rovings), or staple fibers, formed from continuous or discontinuous fibers such as fiberglass, carbon fibers, carbon nanotubes, nanocomposite fibers, polyaramid fibers such as those sold under the trade name KEVLAR®, poly(p-phenylene benzobisoxazole) fibers such as those sold under the trade name ZYLON®, ultra-high molecular weight polyethylene fibers such as those sold under the trade name SPECTRA®, high and low density polyethylene fibers, polypropylene fibers, nylon fibers, cellulose fibers, natural fibers, biodegradable fibers, and combinations thereof.

[0056] Preferably, these fibers (woven or nonwoven) may be coated with the epoxy resin mixture, in solvent or solvent-free form, by standard impregnation methods, in particular filament winding (FW), pultrusion, sheet molding compound, bulk molding compound, autoclave molding, resin infusion, vacuum assisted resin transfer molding (VARTM), resin transfer molding (RTM), wet / hand lay-up, vacuum bag molding, resin impregnation, prepreg, fiber impregnation, compression molding (CM), brushing, spraying, or dipping, casting, injection molding or combinations thereof.

[0057] The present disclosure also includes articles of manufacture comprising the amine-epoxy compositions described above. Such articles may include, but are not limited to, adhesives, coatings, primers, sealants, curing agents, construction products, flooring products, composite products, laminates, potting compounds, grouts, fillers, cementitious grouts, or self-leveling flooring. Additional components or additives can be used with the compositions of the present disclosure to produce articles of manufacture. Furthermore, such coatings, primers, sealants, curing agents, or grouts can be applied to metal or cementitious substrates.

[0058] The present invention relates to a compound of formula (I) [ka] wherein Z is selected from the group consisting of cyclohexyl, phenyl, and methylenebis(cyclohexyl); a and b are independently 0 or 1; and Y is a C1-C 10 The present invention also relates to the use of a monoalkylated diamine of the formula [wherein R is an alkyl group], or a preferred embodiment thereof as described above, as a hardener for epoxy resins. [Example]

[0059] Examples 1 to 9 are methods for synthesizing the curing agents of the present invention.

[0060] Example 1. Synthesis of sec-butylated isophoronediamine, molar ratio 0.5 / 1.0 (MEK:IPD) The synthesis of N-sec-butylisophoronediamine was a one-batch process. 990.3 g (5.815 mol) of isophoronediamine and 209.7 g (2.908 mol) of 2-butanone were charged to a 2 L autoclave batch reactor containing 7.43 g of 5% sulfided platinum on carbon catalyst. The reactor was sealed and subsequently purged with nitrogen and then hydrogen to remove all air from the reactor. The reactor was pressurized to 27.2 atm (400 psig) with hydrogen and heated to 120-140°C. The pressure had increased to 54.4 atm (800 psig) when the rate of hydrogen uptake slowed. The hydrogenation process was continued until the rate of hydrogen uptake dropped below 0.0007 MPa / min (0.1 psi / min). The reactor was cooled to ambient temperature and depressurized, and the reaction product was filtered to remove the catalyst. A rotary evaporator was used to remove water under a vacuum of 30 mmHg and at temperatures up to 100°C. The resulting reaction product was sec-butylated isophoronediamine, the composition of which, as determined by gas chromatography, is shown in the table below and represented by the following structure: Alternatively, the same product could be obtained by the same procedure as above using a 5% palladium on carbon catalyst, with slightly different conversion rates.

[0061] Example 2. Synthesis of sec-butylated isophoronediamine, molar ratio 1.0 / 1.0 (MEK:IPD) The synthesis of N-sec-butylisophoronediamine was a one-batch process. 843.0 g (4.950 mol) of isophoronediamine and 357.0 g (4.950 mol) of 2-butanone were charged to a 2 L autoclave batch reactor containing 6.32 g of 5% sulfided platinum on carbon catalyst. The reactor was sealed and subsequently purged with nitrogen and then hydrogen to remove all air from the reactor. The reactor was pressurized to 27.2 atm (400 psig) with hydrogen and heated to 120-140°C. The pressure had increased to 54.4 atm (800 psig) when the rate of hydrogen uptake slowed. The hydrogenation process was continued until the rate of hydrogen uptake dropped below 0.0007 MPa / min (0.1 psi / min). The reactor was cooled to ambient temperature and depressurized, and the reaction product was filtered to remove the catalyst. A rotary evaporator was used to remove water under a vacuum of 30 mmHg and at a temperature of up to 100°C. The resulting reaction product was sec-butylated isophoronediamine, and its composition determined by gas chromatography is shown in the table below and represented by the following structure. Alternatively, the same product was obtained by the same procedure as above using a 5% palladium on carbon catalyst, with slightly different conversion rates. In this case, the NMR spectrum of the product was performed, and the ratio of the main mono-alkylated IPD to the minor mono-alkylated IPD was 80:20, while the selectivity of the total mono-alkylated IPD was about 90%. [ka] Product composition: [Table 1]

[0062] Example 3. Synthesis of cyclohexylated isophoronediamine, molar ratio 0.5 / 1.0 (CHONE:IPD) The synthesis of N-cyclohexylisophoronediamine is a one-batch process. 465.8 g (2.74 mol) of isophoronediamine and 134.2 g (1.37 mol) of cyclohexanone were charged into a 1 L autoclave batch reactor containing 7.0 g of 5% sulfided platinum-on-carbon catalyst. The reactor was sealed and subsequently purged with nitrogen and then hydrogen to remove all air from the reactor. The reactor was pressurized to 27.2 atm (400 psig) with hydrogen and heated to 120°C. The pressure had increased to 54.4 atm (800 psig) when the rate of hydrogen uptake slowed. This hydrogenation process was continued until the rate of hydrogen uptake dropped below 0.0007 MPa / min (0.1 psi / min). The reactor was cooled to ambient temperature and depressurized, and the reaction product was filtered to remove the catalyst. Water was removed using a rotary evaporator operating under 30 mm Hg vacuum and temperatures up to 100° C. The resulting reaction product was cyclohexylated isophorone diamine, the composition of which, as determined by gas chromatography, is shown in the table below.

[0063] Example 4. Synthesis of cyclohexylated isophorone diamine, molar ratio 1.0 / 1.0 (CHONE:IPD) The synthesis of N-cyclohexylisophoronediamine is a one-batch process. 348.9 g (2.05 mol) of isophoronediamine and 201.1 g (2.05 mol) of cyclohexanone were charged into a 1 L autoclave batch reactor containing 5.2 g of 5% palladium on carbon catalyst. The reactor was sealed and subsequently purged with nitrogen and then hydrogen to remove all air from the reactor. The reactor was pressurized to 27.2 atm (400 psig) with hydrogen and heated to 120°C. The pressure had increased to 54.4 atm (800 psig) when the rate of hydrogen uptake slowed. This hydrogenation process was continued until the rate of hydrogen uptake dropped below 0.0007 MPa / min (0.1 psi / min). The reactor was cooled to ambient temperature and depressurized, and the reaction product was filtered to remove the catalyst. Water was removed using a rotary evaporator operating under 30 mm Hg vacuum and temperatures up to 100° C. The resulting reaction product was cyclohexylated isophorone diamine, the composition of which, as determined by gas chromatography, is shown in the table below. Product composition: [Table 2]

[0064] Example 5. Synthesis of trimethylcyclohexylated isophorone diamine, molar ratio 0.5 / 1.0 (isophorone:IPD) The synthesis of N-trimethylcyclohexylisophoronediamine is a one-batch process. 170.8 g (1.00 mol) of isophoronediamine and 69.2 g (0.50 mol) of isophoronediamine were combined with 240 g of tetrahydrofuran and charged into a 1 L autoclave batch reactor containing 7.2 g of 5% palladium-on-carbon catalyst. The reactor was sealed and subsequently purged with nitrogen and then hydrogen to remove all air from the reactor. The reactor was pressurized to 27.2 atm (400 psig) with hydrogen and heated to 160°C. The pressure had increased to 54.4 atm (800 psig) when the rate of hydrogen uptake slowed. This hydrogenation process was continued until the rate of hydrogen uptake dropped below 0.0007 MPa / min (0.1 psi / min). The reactor was cooled to ambient temperature and depressurized, and the reaction product was filtered to remove the catalyst. Water and tetrahydrofuran were removed using a rotary evaporator operated at 30 mm Hg vacuum and temperatures up to 100° C. The resulting reaction product was trimethylcyclohexylated isophoronediamine, the composition of which, as determined by gas chromatography, is shown in the table below.

[0065] Example 6. Synthesis of trimethylcyclohexylated isophorone diamine, molar ratio 1.0 / 1.0 (isophorone:IPD) The synthesis of N-trimethylcyclohexylisophoronediamine is a one-batch process. 132.5 g (0.78 mol) of isophoronediamine and 107.5 g (0.78 mol) of isophorone were combined with 240 g of tetrahydrofuran and charged into a 1 L autoclave batch reactor containing 3.6 g of 5% palladium on carbon catalyst. The reactor was sealed and subsequently purged with nitrogen and then hydrogen to remove all air from the reactor. The reactor was pressurized to 27.2 atm (400 psig) with hydrogen and heated to 160°C. The pressure had increased to 54.4 atm (800 psig) when the rate of hydrogen uptake slowed. This hydrogenation process was continued until the rate of hydrogen uptake dropped below 0.0007 MPa / min (0.1 psi / min). The reactor was cooled to ambient temperature and depressurized, and the reaction product was filtered to remove the catalyst. Water and tetrahydrofuran were removed using a rotary evaporator operated at 30 mm Hg vacuum and temperatures up to 100° C. The resulting reaction product was trimethylcyclohexylated isophoronediamine, the composition of which, as determined by gas chromatography, is shown in the table below. Product composition: [Table 3]

[0066] Example 7. Synthesis of sec-butylated 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, molar ratio 1.0 / 1.0 (MEK:DMPACM) The synthesis of N-sec-butyl-3,3'-dimethyl-4,4'-diaminodicyclohexylmethane is a one-batch process. 460.7 g (1.93 mol) of 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane and 139.3 g (1.93 mol) of 2-butanone were charged to a 1 L autoclave batch reactor containing 3.46 g of 5% sulfided platinum on carbon catalyst. The reactor was sealed and subsequently purged with nitrogen and then hydrogen to remove all air from the reactor. The reactor was pressurized to 34.0 atm (500 psig) with hydrogen and heated to 160°C. The pressure had increased to 54.4 atm (800 psig) when the rate of hydrogen uptake slowed. The hydrogenation process was continued until the rate of hydrogen uptake dropped below 0.0007 MPa / min (0.1 psi / min). The reactor was cooled to ambient temperature and depressurized, and the reaction product was filtered to remove the catalyst. Water was removed using a rotary evaporator operated under 40 mmHg vacuum and temperatures up to 100°C. The resulting reaction product was sec-butylated 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, the composition of which, as determined by gas chromatography, is shown in the table below and is represented by the following structure: [ka]

[0067] Product composition: [Table 4]

[0068] Example 8. Synthesis of sec-butylated m-xylylenediamine, molar ratio 1.0 / 1.0 (MEK:MXDA) The synthesis of N-sec-butyl-m-xylylenediamine was a one-batch process. 392.3 g (2.88 mol) of m-xylylenediamine and 207.7 g (2.88 mol) of 2-butanone were charged into a 1 L autoclave batch reactor containing 2.94 g of 5% sulfided platinum on carbon catalyst. The reactor was sealed and subsequently purged with nitrogen and then hydrogen to remove all air from the reactor. The reactor was pressurized to 34.0 atm (500 psig) with hydrogen and heated to 120°C. The pressure had increased to 54.4 atm (800 psig) when the rate of hydrogen uptake slowed. This hydrogenation process was continued until the rate of hydrogen uptake dropped below 0.0007 MPa / min (0.1 psi / min). The reactor was cooled to ambient temperature and depressurized, and the reaction product was filtered to remove the catalyst. Water was removed using a rotary evaporator operating under 40 mm Hg vacuum and temperatures up to 100° C. The resulting reaction product was sec-butylated m-xylylenediamine, the composition of which, as determined by gas chromatography, is shown in the table below and is represented by the structure below. [ka]

[0069] Product composition: [Table 5]

[0070] Example 9. Synthesis of sec-butylated 4,4'-diaminodicyclohexylmethane, molar ratio 1.0 / 1.0 (MEK:PACM) The synthesis of N-sec-butyl-4,4'-diaminodicyclohexylmethane is a one-batch process. 446.6 g (2.13 mol) of 4,4'-diaminodicyclohexylmethane and 153.4 g (2.13 mol) of 2-butanone were charged to a 1 L autoclave batch reactor containing 3.40 g of 5% sulfided platinum on carbon catalyst. The reactor was sealed and subsequently purged with nitrogen and then hydrogen to remove all air from the reactor. The reactor was pressurized to 27.2 atm (400 psig) with hydrogen and heated to 140°C. The pressure had increased to 54.4 atm (800 psig) when the rate of hydrogen uptake slowed. The hydrogenation process was continued until the rate of hydrogen uptake dropped below 0.0007 MPa / min (0.1 psi / min). The reactor was cooled to ambient temperature and depressurized, and the reaction product was filtered to remove the catalyst. Water was removed using a rotary evaporator operating under 40 mm Hg vacuum and temperatures up to 100° C. The resulting reaction product was sec-butylated 4,4′-diaminodicyclohexylmethane, the composition of which, as determined by gas chromatography, is shown in the table below and is represented by the following structure: [ka]

[0071] Product composition: [Table 6]

[0072] These examples are provided to demonstrate particular aspects of the invention and are not intended to limit the scope of the claims that follow.

[0073] Example 10. This example describes the preparation and testing of an alkylated IPD hardener with an epoxy resin.

[0074] Table 1 [Table 7]

[0075] A comparison of a commercially available cycloaliphatic amine, such as IPD (Formulation 1), with the mono- and di-alkylated products of the present invention (Formulations 2-4) is reported in Table 1. The neat viscosity of the alkylated isophorone diamine (AIPD) product remains extremely low. The curing agent desirably has a low viscosity, which helps reduce the overall epoxy formulation viscosity for composite applications. The gel time of the alkylated isophorone diamine (AIPD) product with an IPD:MEK ratio of 1:0.5 doubled, and the IPD:MEK ratio of 1:1 increased by nearly five-fold at 25°C. This is sufficient time and viscosity to uniformly process relatively large and relatively thick composite parts.

[0076] The reactivity of the alkylated isophorone diamine (AIPD) product with epoxy resins maintained desirable physical, thermal, and chemical properties for composite applications.

[0077] The curing agent was used to mix with epoxy resin (epoxy equivalent weight (EEW) 180) in various stoichiometric ratios as shown in Table 1. The liquid epoxy resin (LER) (EEW ​​180) was EPON (登録商標) 826. EPON (登録商標) is a registered trademark of Hexion Specialty Chemicals, Inc.

[0078] The viscosity of all formulations shown in Table 1 was measured at 25° C. and 40° C. using a Brookfield viscometer RV with spindle number 27. 12 g of the epoxy resin composition was used to measure the viscosity.

[0079] TECHNE (登録商標) A gel timer was used to measure the gel time of all formulations shown in Table 1. In industry, gel time is sometimes also equivalent to pot life. One end of the metal rod was attached to the TECHNE (登録商標)The beaker is connected to a gel timer and has a 1" diameter disk on the other end. The epoxy resin and hardener were preheated separately at 25°C. A total of 150g of the mixture (epoxy resin and hardener) was mixed for 3-5 minutes. The 1" diameter disk was immersed into the mixture of the beaker contents and the gel timer was turned on, giving an immediate accurate reading.

[0080] The results for Formulations 1-4 are reported in Table 1. Formulation 1, in accordance with the present disclosure, was used as a control and provided an initial mix viscosity of approximately 319 cP. Formulations 2 and 3 exhibited initial mix viscosities of approximately 313 cP and 206 cP, respectively. Lower mix viscosities enhance fiber wetting in thick composite sections under pressure due to improved resin penetration between the fabric layers. Formulation 1 provided a Tg in the range of 140°C to 155°C, and Formulations 2 and 3 provided a Tg in the range of 130°C to 150°C. The alkylated isophorone diamine (AIPD) maintained its Tg range relative to non-alkylated IPD while improving the gel time by 2-5 times over the control formulation (IPD).

[0081] Table 2 [Table 8]

[0082] The handling properties of the alkylated IPD with two different ratios of CHONE and isophorone are reported in Table 2 (Formulations 5-8). The neat viscosity of the alkylated product remains extremely low. It is desirable for the curing agent to have a low viscosity, which helps reduce the overall epoxy formulation viscosity for composite applications. The reactivity of both alkylated products is significantly slowed. This characteristic allows sufficient time and viscosity for uniform processing of relatively large and relatively thick composite parts.

[0083] Example 11 This example describes the testing of a cured epoxy resin formulation.

[0084] Table 3 [Table 9]

[0085] The epoxy resins and amine hardeners shown in Table 3 were mixed by hand at 40°C for 3-5 minutes. Entrapped air was removed by placing the mixture in a centrifuge for 5 minutes, or until the mixture was clear. The mixture was then poured into 1 / 8" aluminum molds. The systems in the molds were cured at 60°C for 1 hour and then at 150°C for 2 hours. The molds were cooled to room temperature before removing the cured samples. Test specimens were prepared from the cast samples according to ASTM methods for mechanical testing: tensile (ASTM D638), flexural (ASTM D790), and compression (ASTM D695). Additional 1" x 3" x 1 / 8" specimens were prepared for chemical resistance testing in different reagents (Table 4).

[0086] Example 12 This example describes the testing of cured epoxy resin formulations after chemical soaking.

[0087] Table 4 [Table 10]

[0088] Neat cast panels of Formulations 1-3 were produced using the process described in Example 11. Flexural specimens (½″×3″×⅛″) were machined according to ASTM D790. The specimens were immersed in different reagents at 40° C. for 30 days to understand the flexural modulus retention before and after immersion. The reagents used were: deionized water, methanol, 10% ammonium hydroxide, and 10% nitric acid. The flexural modulus of Formulations 2 and 3 was mostly retained in the reagents.

[0089] Example 13 This example describes the processing and thermal properties of the alkylation products of different cycloaliphatic amines.

[0090] Table 5 [Table 11]

[0091] A comparison of commercially available amines, such as IPD, MXDA, PACM, and DMPACM (Formulations 1, 9, 11, and 13), with the mono-alkylated products of these amines (Formulations 3, 10, 12, and 14) of the present invention is reported in Table 5. The neat viscosity of the alkylated products remains extremely low. It is desirable for the curing agent to have a low viscosity, which helps reduce the overall epoxy formulation viscosity for composite applications. The gel time of the alkylated products (Formulations 3, 10, 12, and 14) increased by nearly five times at 25°C. This is sufficient time and viscosity to uniformly process relatively large and relatively thick composite parts.

[0092] Preferred embodiments of the present invention are as follows: 1. An epoxy resin and a copolymer of formula (I) [ka] [Wherein Z is cyclohexyl, C1-C 10 Alkyl-substituted cyclohexyl, phenyl, C1-C 10 Alkyl-substituted phenyl, methylenebis(cyclohexyl) and C1-C 10 alkyl-substituted methylenebis(cyclohexyl), a and b are independently 0 or 1, and Y is selected from the group consisting of C1-C 10 and a monoalkylated diamine of the formula [alkyl]. 2. The monoalkylated diamine has the structure: [ka] wherein each of R1, R2, R3, R4, R5, and R6 is H, CH3, or a C2-C4 alkyl group; n is 0 or 1; and A is H, and B is a C1-C4 alkyl group.10 alkyl, or B is H and A is C1-C 10 Epoxy resin system according to claim 1, wherein the alkyl is alkyl. 3. The monoalkylated diamine is i) Structure: [ka] [Wherein A is C1 to C 10 monoalkylated isophorone diamine represented by the formula: ii) Structure: [ka] [Wherein B is C1 to C 10 monoalkylated isophorone diamine represented by the formula: iii) Structure: [ka] [Wherein A is C1 to C 10 monoalkylated methylcyclohexyldiamine represented by the formula: iv) Structure: [ka] [Wherein B is C1 to C 10 monoalkylated methylcyclohexyldiamines represented by the formula: v) Structure: [ka] [Wherein A is C1 to C 10 a monoalkylated cyclohexyldiamine represented by the formula Epoxy resin system according to claim 2, selected from the group consisting of: 4. The monoalkylated diamine has the structure: [ka] wherein each of R1 and R2 is H or CH3; and A is C1-C 10 Epoxy resin system according to claim 1, wherein the alkyl is alkyl. 5. The monoalkylated diamine is i) Structure: [ka] [Wherein A is C1 to C 10 monoalkylated 4,4'-methylenebis(cyclohexylamine), wherein the alkyl is an alkyl; and ii) Structure: [ka] [Wherein A is C1 to C 10 Monoalkylated 2,2'-dimethyl-4,4'-methylenebis(cyclohexylamine) represented by the formula 5. The epoxy resin system according to claim 4, selected from the group consisting of: 6. The monoalkylated diamine has the structure: [ka] wherein X is a phenyl group or a cyclohexyl group; and A is a C1-C 10 Epoxy resin system according to claim 1, wherein the alkyl is alkyl. 7. The monoalkylated diamine is i) Structure: [ka] [Wherein A is C1 to C 10 monoalkylated m-xylylenediamine represented by the formula: ii) Structure: [ka] [Wherein A is C1 to C 10 Monoalkylated 1,3-bisaminomethylcyclohexane represented by the formula: 7. The epoxy resin system according to claim 6, selected from the group consisting of: 8. The epoxy resin system according to claim 1, wherein the epoxy resin system comprises at least 20% by weight of the monoalkylated diamine, based on the total weight of the curing agent. 9. The epoxy resin system of claim 1, further comprising a second amine selected from the group consisting of primary amines and secondary amines. 10. The epoxy resin system according to claim 9, wherein the second amine component comprises one or more amine compounds selected from the group consisting of polyetheramines, polyetherpolyamines, saturated aliphatic cyclic diamines, linear aliphatic amines, cycloaliphatic amines, polycyclic aliphatic amines, and aromatic amines. 11. The epoxy resin system of claim 1, wherein the epoxy resin component comprises at least one glycidyl ether selected from the group consisting of glycidyl ethers of resorcinol, hydroquinone, bis-(4-hydroxy-3,5-difluorophenyl)-methane, 1,1-bis-(4-hydroxyphenyl)-ethane, 2,2-bis-(4-hydroxy-3-methylphenyl)-propane, 2,2-bis-(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis-(4-hydroxyphenyl)-propane, bis-(4-hydroxyphenyl)-methane, and any combination thereof. 12. The epoxy resin component has the following structure: [ka] 2. The epoxy resin system according to 1 above, comprising at least one dihydric phenol of the formula: [wherein m is 0 to 25 and R is a divalent hydrocarbon group]. 13. The epoxy resin component is selected from the group consisting of bis(3,4-epoxycyclohexylmethyl)oxalate, bis(3,4-epoxycyclohexylmethyl)adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, vinylcyclohexene diepoxide; limonene diepoxide; bis(3,4-epoxycyclohexylmethyl)pimelate; dicyclopentadiene diepoxide; 3,3-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 3,4-epoxycyclohexylmethyl-3,4- 2. The epoxy resin system of claim 1, comprising at least one member selected from the group consisting of epoxy cyclohexane carboxylate; 3,3-epoxy-1-methylcyclohexyl-methyl-3,4-epoxy-1-methylcyclohexane carboxylate; 6-methyl-3,4-epoxycyclohexylmethyl-6-methyl-3,4-epoxycyclohexane carboxylate; 3,4-epoxy-2-methylcyclohexyl-methyl-3,4-epoxy-3-methylcyclohexane carboxylate, and combinations thereof. 14. A method for producing an epoxy resin system according to any one of 1 to 13 above, comprising: adding an epoxy resin to a compound represented by formula (I) [ka] wherein Z is selected from the group consisting of cyclohexyl, C1-C4 alkyl-substituted cyclohexyl, phenyl, C1-C4 alkyl-substituted phenyl, methylenebis(cyclohexyl), and C1-C4 alkyl-substituted methylenebis(cyclohexyl); a and b are independently 0 or 1; and Y is C1-C 10 and optionally other ingredients. 15. Use of an epoxy resin system according to any one of 1 to 14 above for producing structural or electrical laminates, coatings, castings, structural components, circuit boards, electrical varnishes, encapsulants, semiconductors, general purpose molding powders, filament wound pipe and fittings, filament wound pressure vessels, low and high pressure pipe and fittings, low and high pressure vessels, storage tanks, wind turbine blades, automotive structural parts, aerospace structural parts, oil and gas buoyancy modules, rigs, well plugs, cured in place pipe (CIPP), structural adhesives and laminates, composite liners, pump liners, corrosion resistant coatings or composites based on reinforcing fibre substrates. 16. Compounds of formula (I) as hardeners for epoxy resins [ka] wherein Z is selected from the group consisting of cyclohexyl, C1-C4 alkyl-substituted cyclohexyl, phenyl, C1-C4 alkyl-substituted phenyl, methylenebis(cyclohexyl), and C1-C4 alkyl-substituted methylenebis(cyclohexyl); a and b are independently 0 or 1; and Y is C1-C 10 The use of monoalkylated diamines in which the alkyl is alkyl.

Claims

1. an epoxy resin and a compound represented by formula (I) 【Chemistry 1】 [Wherein Z represents methylenebis(cyclohexyl) and C １ ~C １０ and a monoalkylated diamine selected from the group consisting of alkyl-substituted methylenebis(cyclohexyl), a and b are independently 0 or 1, and Y is a cyclohexyl group, a sec-butyl group, a trimethylcyclohexyl group, or an isopropyl group; The monoalkylated diamine has the structure: 【Chemistry 2】 [In the formula, R １ and R ２ Each of ３ and A is a cyclohexyl group, a sec-butyl group, a trimethylcyclohexyl group, or an isopropyl group.

2. The monoalkylated diamine is i) Structure: 【Transformation 3】 monoalkylated 4,4'-methylenebis(cyclohexylamine) represented by the formula: wherein A is a cyclohexyl group, a sec-butyl group, a trimethylcyclohexyl group, or an isopropyl group; and ii) Structure: 【Chemistry 4】 Monoalkylated 2,2'-dimethyl-4,4'-methylenebis(cyclohexylamine) represented by the formula: [wherein A is a cyclohexyl group, a sec-butyl group, a trimethylcyclohexyl group, or an isopropyl group] 2. The epoxy resin system of claim 1, selected from the group consisting of:

3. 10. The epoxy resin system of claim 1, wherein the epoxy resin system comprises at least 20% by weight of the monoalkylated diamine, based on the total weight of the curing agent.

4. 10. The epoxy resin system of claim 1, wherein the epoxy resin system further comprises a second amine selected from the group consisting of primary amines and secondary amines.

5. 5. The epoxy resin system of claim 4, wherein the second amine component comprises one or more amine compounds selected from the group consisting of polyetheramines, polyetherpolyamines, saturated aliphatic cyclic diamines, linear aliphatic amines, cycloaliphatic amines, polycyclic aliphatic amines, and aromatic amines.

6. 2. The epoxy resin system of claim 1, wherein the epoxy resin component comprises at least one glycidyl ether selected from the group of glycidyl ethers of resorcinol, hydroquinone, bis-(4-hydroxy-3,5-difluorophenyl)-methane, 1,1-bis-(4-hydroxyphenyl)-ethane, 2,2-bis-(4-hydroxy-3-methylphenyl)-propane, 2,2-bis-(4-hydroxy-3,5-dichlorophenyl)propane, 2,2-bis-(4-hydroxyphenyl)-propane, bis-(4-hydroxyphenyl)-methane, and any combination thereof.

7. The epoxy resin component has the following structure: 【Transformation 5】 2. The epoxy resin system of claim 1, comprising at least one glycidyl ether of a dihydric phenol of the formula: wherein m is 0 to 25 and R is a divalent hydrocarbon radical of a dihydric phenol.

8. The epoxy resin component may be selected from the group consisting of bis(3,4-epoxycyclohexylmethyl)oxalate, bis(3,4-epoxycyclohexylmethyl)adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, vinylcyclohexene diepoxide; limonene diepoxide; bis(3,4-epoxycyclohexylmethyl)pimelate; dicyclopentadiene diepoxide; 3,3-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexylmethyl-3,4-ene 2. The epoxy resin system of claim 1, comprising at least one member selected from the group consisting of: 3,3-epoxy-1-methylcyclohexyl-methyl-3,4-epoxy-1-methylcyclohexanecarboxylate; 6-methyl-3,4-epoxycyclohexylmethyl-6-methyl-3,4-epoxycyclohexanecarboxylate; 3,4-epoxy-2-methylcyclohexyl-methyl-3,4-epoxy-3-methylcyclohexanecarboxylate, and combinations thereof.

9. 9. A method for producing an epoxy resin system according to any one of claims 1 to 8, comprising: 【Transformation 6】 [Wherein Z is methylenebis(cyclohexyl), and C １ ~C ４ alkyl-substituted methylenebis(cyclohexyl), a and b are independently 0 or 1, and Y is a cyclohexyl group, a sec-butyl group, a trimethylcyclohexyl group, or an isopropyl group, and optionally other components, wherein the monoalkylated diamine has the structure: 【Transformation 7】 [In the formula, R １ and R ２ Each of ３ and A is a cyclohexyl group, a sec-butyl group, a trimethylcyclohexyl group, or an isopropyl group.

10. 9. Use of an epoxy resin system according to any of claims 1 to 8 for the production of structural or electrical laminates, coatings, castings, structural components, circuit boards, electrical varnishes, encapsulants, semiconductors, general purpose molding powders, filament wound pipe and fittings, filament wound pressure vessels, low and high pressure pipe and fittings, low and high pressure vessels, storage tanks, wind turbine blades, automotive structural parts, aerospace structural parts, oil and gas buoyancy modules, rigs, well plugs, cured in place pipe (CIPP), structural adhesives and laminates, composite liners, pump liners, corrosion resistant coatings or composites based on reinforcing fibre substrates.

11. as hardeners for epoxy resins, 【Transformation 8】 [Wherein Z is methylenebis(cyclohexyl), and C １ ~C ４ alkyl-substituted methylenebis(cyclohexyl), a and b are independently 0 or 1, and Y is a cyclohexyl group, a sec-butyl group, a trimethylcyclohexyl group, or an isopropyl group, wherein the monoalkylated diamine has the structure: 【Chemistry 9】 [In the formula, R １ and R ２ Each of ３ and A is a cyclohexyl group, a sec-butyl group, a trimethylcyclohexyl group, or an isopropyl group.

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