阅读说明：本技术 硬化剂及其制备方法 (Hardening agent and preparation method thereof ) 是由 廖德超 徐森煌 苏崇智 周全 林瑞荣 于 2020-02-14 设计创作，主要内容包括：本发明公开一种硬化剂的制备方法,其包含：酯化步骤：混合多元醇与多元酸酐,以得到酯基乳化剂(A)；扩链步骤：混合酯基乳化剂(A)与双官能性环氧树脂,以得到聚合物中间体(B)；以及混合反应聚合物中间体(B)与多胺化合物,以得到硬化剂(C)。通过本发明的步骤流程以及特定比例,提供了无须额外添加挥发性有机化合物的硬化剂制备方法,并提供具有良好性能的硬化产物。(The invention discloses a preparation method of a hardening agent, which comprises the following steps: an esterification step: mixing a polyol with a polybasic acid anhydride to obtain an ester-based emulsifier (a); chain extension: mixing an ester-based emulsifier (a) with a bifunctional epoxy resin to obtain a polymer intermediate (B); and mixing the reaction polymer intermediate (B) with a polyamine compound to obtain a hardener (C). The invention provides a preparation method of the hardening agent without adding any volatile organic compound and provides a hardening product with good performance through the step flow and the specific proportion.)

1. A method for preparing a hardener, the method comprising:

an esterification step: mixing the raw materials in a ratio of 1.1: mixing a polyol and a polybasic acid anhydride in an equivalent ratio of 1 to perform an esterification reaction to obtain an ester-based emulsifier (A);

chain extension: mixing the components in a ratio of 0.05: mixing the ester-based emulsifier (A) and a bifunctional epoxy resin in an equivalent ratio of 1 to carry out chain extension to obtain a polymer intermediate (B); and

reacting the polymer intermediate (B) with a polyamine compound in a ratio of 0.2: 1 equivalent ratio to obtain a hardening agent (C):

wherein m is 1-100, n is 1-15, X and Y are each independently selected from H, methyl, ethyl, hydroxymethyl; r₀Is a C6 to C30 hydrocarbon group substituted or unsubstituted with an oxygen atom, a nitrogen atom, a sulfur atom, and having at least one aromatic ring, or a C6 to C17 aliphatic hydrocarbon group; r₁Is a C2 to C18 aliphatic, alicyclic or aromatic radical substituted or unsubstituted with a non-reactive oxygen, up to an average of 4 secondary or tertiary nitrogen atoms; r₂And R₃Each independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or R₂And R₃Bonded to each other to form a substituted or unsubstituted ring.

2. The method of preparing a hardener as set forth in claim 1 wherein said polyol has the formula:

wherein m is 1-100, n is 1-15, and X and Y are each independently selected from H, methyl, ethyl or hydroxymethyl.

3. The method of claim 1, wherein the polybasic acid anhydride is at least one selected from the group consisting of succinic anhydride, maleic anhydride, phthalic anhydride, trans-1, 2-cyclohexanecarboxylic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and combinations thereof.

4. The method of claim 1, wherein the difunctional epoxy resin is selected from at least one of the group consisting of diglycidyl ethers of dihydric phenols, branched or linear aliphatic glycidyl ethers, epoxy novolac resins, and cycloaliphatic epoxy resins.

5. The method of claim 1, wherein the polyamine compound is at least one selected from the group consisting of m-xylylenediamine, 1, 3-bis (aminomethyl) cyclohexane, 2-methyl-1, 5-pentanediamine, 1, 3-pentanediamine, ethylenediamine, diethylenetriamine, triethylenetetramine, polypropyleneoxide diamine, 2(4), 4-trimethyl-1, 6-hexanediamine, isophoronediamine, 2, 4-toluenediamine, 1, 6-hexanediamine, 1, 2-diaminocyclohexane, and diaminodicyclohexylmethane.

6. The method for preparing a hardener as set forth in claim 1, wherein said esterification step is carried out under a nitrogen atmosphere, the reaction temperature of said esterification step is between 110 and 130 ℃, and the reaction time is 3 hours.

7. The method of preparing a hardener as set forth in claim 1 wherein said step of chain extending comprises: the ester-based emulsifier (A) is reacted with the bifunctional epoxy resin at a temperature of 110 to 130 ℃ for 1 hour and then at a temperature of 130 to 150 ℃ for 2 hours.

8. The method for preparing a hardener as set forth in claim 1, wherein the reaction of the polymer intermediate (B) with the polyamine compound is carried out at a temperature of 70 ℃ for 4 hours.

9. The method for preparing a hardener as set forth in claim 4, further comprising: and (C) subjecting the hardener (C) to an end-capping reaction with a monofunctional epoxy compound, and mixing the obtained product with deionized water to obtain an end-capped hardener (D):

wherein R is₁Is a C2 to C18 aliphatic, alicyclic or aromatic radical substituted or unsubstituted with a non-reactive oxygen, up to an average of 4 secondary or tertiary nitrogen atoms; m-1-100, n-1-15, X and Y are each independently selected from H, methyl, ethyl, hydroxymethyl; r₂And R₃Each independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or R₂And R₃Bonded to each other to form a substituted or unsubstituted ring; r₀Is a C6 to C30 hydrocarbon group substituted or unsubstituted with an oxygen atom, a nitrogen atom, a sulfur atom, and having at least one aromatic ring, or a C6 to C17 aliphatic hydrocarbon group.

10. The method of claim 9, wherein the monofunctional epoxy compound is selected from the group consisting of 1, 2-hexenedioxide, 1, 2-heptyleneoxide, isoheptyleneoxide, 1, 2-octenyloxide, 1, 2-dodecene monooxide, 1, 2-pentadecene oxide, butadiene monooxide, isopentadiene monooxide, styrenated oxide, methyl glycidyl ether, ethyl glycidyl ether, phenyl glycidyl ether, n-butyl glycidyl ether, tolyl glycidyl ether, isopropyl glycidyl ether, benzyl glycidyl ether, glycidoxypropyltrimethoxysilane, octyl glycidyl ether, nonyl glycidyl ether, decyl glycidyl ether, dodecyl alkyl glycidyl ether, C12, C14 alkyl monoglycidyl ether, p-tert-butylphenyl glycidyl ether, and o-tolyl glycidyl ether At least one of the groups.

11. A hardener, wherein the hardener is prepared by the method of claim 1.

Technical Field

The invention relates to a hardener and a preparation method thereof, in particular to a hardener for a water-based epoxy resin coating and a preparation method thereof.

Background

The cured product of the epoxy resin composition has excellent mechanical properties, corrosion resistance, adhesion and the like, and thus is widely applied to the fields of coatings, adhesives, laminated plates, electronic parts and the like; epoxy resins are chemically resistant and also adhere well to most substrates. However, the epoxy resins of the prior art are generally insoluble in water, only soluble in organic solvents such as alcohols, ketones, aromatic hydrocarbons and the like, and generally have to be applied under the condition of using a large amount of organic solvents.

As people begin to pay attention to health and environmental pollution problems, the influence of volatile organic solvents and Volatile Organic Compounds (VOCs) on human bodies and the environment is receiving high attention. Specifically, the Volatile Organic Compound (VOC) may be listed as a volatile solvent according to the american society for Environmental Protection (EPA) method 24, or an organic compound described as a VOC in European Union Directive 2004/42/EC, for example, methanol, ethanol, propanol, isopropanol, acetoxysilane, 2-methoxyethanol, and the like. Therefore, organic compounds without volatility (NOC) or with low volatility have been the relevant research direction for epoxy resin materials.

U.S. Pat. No. 4,197,389 discloses a method of making a hardener: reacting at least one polyepoxide compound with at least one polyalkylene polyether polyol to form an adduct that is subsequently reacted with a polyamine. U.S. patent No. 5,489,630 discloses a water-compatible polyamine-epoxy resin adduct by reacting a poly (alkylene oxide) mono-or diamine with a polyepoxide to form an intermediate, which is then subsequently reacted with an excess of a polyamine. U.S. Pat. No. 6,013,757 discloses aqueous polyamide hardeners prepared from the reaction of long chain dicarboxylic acids and aminoalkylpiperazines. U.S. Pat. No. 6,127,459 discloses the production of an amine-terminated hardener by reacting a polyamine with an epoxy resin to produce an amine-terminated intermediate, and reacting the amine-terminated intermediate with compounds (I), (II), (III) containing an acid-terminated polyalkylene glycol.

However, the preparation process of the related art still uses a considerable amount of organic solvent, and in order to overcome the aforementioned drawbacks, it has become one of the important issues to be solved by the industry to prepare a water-compatible solvent-free hardener and provide a hardened product with good properties.

Disclosure of Invention

The invention aims to solve the technical problem of providing a hardening agent for a water-based epoxy resin coating and a preparation method thereof aiming at the defects of the prior art.

In order to solve the above technical problem, one technical solution adopted by the present invention is to provide a method for preparing a hardener, comprising: an esterification step: mixing the raw materials in a ratio of 1.1: mixing a polyol and a polybasic acid anhydride in an equivalent ratio of 1 to perform an esterification reaction to obtain an ester-based emulsifier (A); chain extension: mixing the components in a ratio of 0.05: mixing the ester-based emulsifier (A) and a bifunctional epoxy resin in an equivalent ratio of 1 to carry out chain extension to obtain a polymer intermediate (B); and reacting the polymer intermediate (B) with a polyamine compound in a ratio of 0.2: 1 equivalent ratio to obtain a hardening agent (C):

wherein m is 1-100, n is 1-15, X and Y are each independently selected from H, methyl, ethyl, hydroxymethyl; r₀An aliphatic hydrocarbon group which is a C6 to C30 hydrocarbon group substituted or unsubstituted with an oxygen atom, a nitrogen atom, a sulfur atom, and has at least one aromatic ring, or C6 to C17; r₁Is a C2 to C18 aliphatic, alicyclic or aromatic radical substituted or unsubstituted with a non-reactive oxygen, up to an average of 4 secondary or tertiary nitrogen atoms; r₂And R₃Each independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or R₂And R₃Bonded to each other to form a substituted or unsubstituted ring.

Preferably, the polyol has the following formula:

wherein m is 1-100, n is 1-15, and X and Y are each independently selected from H, methyl, ethyl or hydroxymethyl. Still further, the polyethylene glycol may be selected from: PEG200, PEG400, PEG 1000, PEG 2000, PEG 3000, PEG6000, and PEG 8000.

Preferably, the polybasic acid anhydride is at least one selected from the group consisting of succinic anhydride, maleic anhydride, phthalic anhydride, trans-1, 2-cyclohexanecarboxylic anhydride, tetrahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

Preferably, the difunctional epoxy resin may be selected from at least one of the group consisting of diglycidyl ethers of dihydric phenols, branched or linear aliphatic glycidyl ethers, epoxy novolac resins, or cycloaliphatic epoxy resins.

Preferably, the polyamine compound is at least one selected from the group consisting of m-xylylenediamine, 1, 3-bis (aminomethyl) cyclohexane, 2-methyl-1, 5-pentanediamine, 1, 3-pentanediamine, ethylenediamine, diethylenetriamine, triethylenetetramine, polypropylenediamine oxide, 2(4), 4-trimethyl-1, 6-hexanediamine, isophoronediamine, 2, 4-toluenediamine, 1, 6-hexanediamine, 1, 2-diaminocyclohexane, and diaminodicyclohexylmethane (PACM).

Preferably, the esterification step is carried out under a nitrogen atmosphere, the polybasic acid anhydride and the polyol are reacted at a temperature of between 110 and 130 ℃ for a reaction time of 3 hours.

Preferably, the reaction of the polymer intermediate (B) with the polyamine compound is carried out at a temperature of 70 ℃ for 4 hours.

Preferably, the preparation method of the hardener of the present invention further comprises: and (C) carrying out an end-capping reaction on the hardener (C) and a monofunctional epoxy compound, and mixing the hardener (C) and deionized water to obtain a hardener (D):

wherein R is₁Is a C2 to C18 aliphatic, alicyclic or aromatic radical substituted or unsubstituted with a non-reactive oxygen, up to an average of 4 secondary or tertiary nitrogen atoms; wherein m is 1-100, n is 1-15, X and Y are each independently selected from H, methyl, ethyl, hydroxymethyl; r₂And R₃Each independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or R₂And R₃Bonded to each other to form a substituted or unsubstituted ring; r₀Is a C6 to C30 hydrocarbon group substituted or unsubstituted with an oxygen atom, a nitrogen atom, a sulfur atom, and having at least one aromatic ring, or a C6 to C17 aliphatic hydrocarbon group.

Preferably, the monofunctional epoxy compound is selected from the group consisting of 1, 2-hexenedioxide, 1, 2-heptyleneoxide, isoheptyleneoxide, 1, 2-octenyloxide, 1, 2-dodecenylmonooxide, 1, 2-pentadecenyloxide, butadiene monooxide, isopentadiene monooxide, styrenated oxide, methyl glycidyl ether, ethyl glycidyl ether, phenyl glycidyl ether, n-butyl glycidyl ether, tolyl glycidyl ether, isopropyl glycidyl ether, benzyl glycidyl ether, glycidoxypropyltrimethoxysilane, octyl glycidyl ether, nonyl glycidyl ether, decyl glycidyl ether, dodecyl glycidyl ether, C12, C14 alkyl monoglycidyl ether, p-tert-butylphenyl glycidyl ether, and o-tolyl glycidyl ether.

In order to solve the above technical problem, another technical solution adopted by the present invention is to provide a hardener, which is prepared by the preparation method of the hardener.

One of the advantages of the present invention is that the hardener and the preparation method thereof provided by the present invention can provide a preparation method of the hardener without adding any additional volatile organic compound, prepare a water-compatible solvent-free hardener, and provide a hardened product with good performance through the step flow and the technical scheme of the specific ratio.

For a better understanding of the features and technical content of the present invention, reference should be made to the following detailed description of the invention and accompanying drawings, which are provided for purposes of illustration and description only and are not intended to limit the invention.

Drawings

FIG. 1 is a flow chart of a method for manufacturing a hardener according to the present invention.

FIG. 2 is an NMR spectrum of a hardening agent of the present invention.

FIG. 3 is an FT-IR spectrum of a hardener of the present invention.

Detailed Description

The following is a description of the embodiments of the "hardener and method for preparing the same" disclosed in the present invention by specific examples, and those skilled in the art can understand the advantages and effects of the present invention from the disclosure in the present specification. The invention is capable of other and different embodiments and its several details are capable of modification and various other changes, which can be made in various details within the specification and without departing from the spirit and scope of the invention. The drawings of the present invention are for illustrative purposes only and are not intended to be drawn to scale. The following embodiments will further explain the related art of the present invention in detail, but the disclosure is not intended to limit the scope of the present invention.

It should be understood that although the terms first, second, third, etc. may be used herein to describe various components or sections, these components or sections should not be limited by these terms. These terms are used primarily to distinguish one element from another element or from one portion to another portion. In addition, the term "or" as used herein should be taken to include any one or combination of more of the associated listed items as the case may be.

The articles "a" and "an" are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. For example, "mono-epoxy" refers to one epoxy group or more than one epoxy group. If the specification states a component or element "may", "may" be included or having a certain characteristic, that particular component or element does not necessarily have to be included or have that characteristic.

The term "parts by weight" as used herein means the amount of additives (PHR) per hundred parts of rubber (or resin). The term "wt%" stands for weight percent.

Unless otherwise specified, the term "polymer" independently includes polymers, oligomers, copolymers, terpolymers, block copolymers, segmented copolymers, prepolymers, graft copolymers, and any mixtures or combinations thereof. The term "resin" independently includes polymers, oligomers, copolymers, terpolymers, block copolymers, segmented copolymers, prepolymers, graft copolymers, and any mixtures or combinations thereof.

It is to be understood that the term "independently selected" means that the same or different values can be selected for multiple instances of a given variable in a single compound. The term "substituted or unsubstituted" means that the hydrogen group of the specified moiety is replaced by a group of the specified substituent, provided that the substitution results in a stable or chemically feasible compound. The combinations of substituents envisaged by the present invention are preferably those which allow the formation of stable or chemically feasible compounds.

Referring to fig. 1, the present invention provides a method for preparing a hardener, including: step S100 (esterification step), carrying out esterification reaction on polybasic acid anhydride and polyhydric alcohol to obtain an ester-based emulsifier; step S200 (chain extension step), reacting an ester-based emulsifier with a bifunctional epoxy compound to obtain a polymer intermediate; step S300 of reacting the polymer intermediate with a polyamine compound to obtain a hardener, and step S400 (end-capping step) of reacting the hardener with a monofunctional epoxy compound.

Specifically, step S100 is performed under a nitrogen atmosphere at a ratio of 1.1: mixing a polyol and a polybasic acid anhydride in an equivalent ratio of 1, and reacting at a temperature of 110 to 130 ℃ for 3 hours to perform an esterification reaction on the polyol and the polybasic acid anhydride to obtain an ester-based emulsifier (A) having the formula:

wherein m is 1-100, n is 1-15, X and Y are each independently selected from H, methyl, ethyl, hydroxymethyl; r₂And R₃Each independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or R₂And R₃Bonded to each other to form a substituted or unsubstituted ring.

Further, the polyols used in the present invention have the following formula:

more particularly, where m is 1-100, n is 1-15, X and Y are each independently selected from H, methyl, ethyl, hydroxymethyl, preferably the polyol polymer has a molecular weight of preferably 200 to 8000. The high molecular weight polyethylene glycol PEG may be selected from: PEG200, PEG400, PEG 1000, PEG 2000, PEG 3000, PEG6000, and PEG 8000.

Further, the polybasic acid anhydrides have the following formula:

wherein R is₂And R₃Each independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or R₂And R₃Bonded to each other to form a substituted or unsubstituted ring.

For example, the polybasic acid anhydride is at least one selected from the group consisting of Succinic Anhydride (SA), Maleic Anhydride (MA), Phthalic Anhydride (PA), trans-1, 2-cyclohexanecarboxylic anhydride (CDA), tetrahydrophthalic anhydride (TPA), methylhexahydrophthalic anhydride (MHHPA), and the like.

S200 chain extension step: mixing the components in a ratio of 0.05: mixing the ester-based emulsifier (A) and a bifunctional epoxy resin at an equivalent ratio of 1 to perform a chain extension reaction, wherein the reaction conditions of the chain extension step are that the reaction is performed at a temperature of 110 to 130 ℃ for 1 hour, and then at a temperature of 130 to 150 ℃ for 2 hours to obtain a polymer intermediate (B) having the chemical formula:

wherein R is₀Is a C6 to C30 hydrocarbon group substituted or unsubstituted with an oxygen atom, a nitrogen atom, a sulfur atom, and having at least one aromatic ring, or a C6 to C17 aliphatic hydrocarbon group; m-1-100, n-1-15, X and Y are each independently selected from H, methyl, ethyl, hydroxymethyl; r₂And R₃Each independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or R₂And R₃Bonded to each other to form a substituted or unsubstituted ring.

Difunctional epoxy resin means that the resin has two or more epoxy groups in one molecule, for example, epoxy groups formed via oxidation of olefins, glycidyl etherification of hydroxyl groups, glycidyl amination of primary or secondary amines, or glycidyl esterification of carboxylic acids. The difunctional epoxy resin of the present invention has the following chemical formula:

wherein n is a natural number, n is 1-10, R₀Is substituted or unsubstituted by oxygen, nitrogen, or sulfur atomsA hydrocarbon group of C6 to C30 and having at least one aromatic ring, or an aliphatic hydrocarbon group of C6 to C17.

For example, the difunctional epoxy resin may be at least one selected from the group consisting of diglycidyl ethers of bisphenol type, branched or linear aliphatic glycidyl ethers, epoxy novolac resins, or cycloaliphatic epoxy resins.

Further, the diglycidyl ether of a dihydric phenol can be produced, for example, by reacting an epihalohydrin with a dihydric phenol in the presence of a base. For example, the dihydric phenol may be at least one selected from the group consisting of 2, 2-bis (4-hydroxyphenyl) propane (bisphenol-a), 2-bis (4-hydroxy-3-t-butylphenyl) propane, 1-bis (4-hydroxyphenyl) ethane, 1-bis (4-hydroxyphenyl) isobutane, bis (2-hydroxy-1-naphthyl) methane, 1, 5-dihydroxynaphthalene and 1, 1-bis (4-hydroxy-3-alkylphenyl) ethane.

The aliphatic glycidyl ether may be selected from the diglycidyl ethers of 1, 4-butanediol, neopentyl glycol, cyclohexanedimethanol, hexanediol, polypropylene glycol, and similar diols, the triglycidyl ethers of trimethylolethane and trimethylolpropane. Examples of cycloaliphatic epoxy resins are: 3, 4-epoxycyclohexylmethyl- (3, 4-epoxy) cyclohexanecarboxylate, a dialicyclic diether diepoxy [2- (3, 4-epoxy) cyclohexyl-5, 5-spiro (3, 4-epoxy) -cyclohexane-m-dioxane ], bis (3, 4-epoxy-cyclohexylmethyl) adipate, bis (3, 4-epoxy-cyclohexyl) adipate, and vinylcyclohexene dioxide [4- (1, 2-epoxyethyl) -1, 2-epoxycyclohexane ].

S300 reacting the polymer intermediate (B) with a polyamine compound in a ratio of 0.2: 1 equivalent ratio and reacted at a temperature of 70 ℃ for 4 hours to obtain a hardener (C) having the formula:

wherein m is 1-100, n is 1-15, X and Y are each independently selected from H, methyl, ethyl, hydroxymethyl; r₀Is a C6 to C30 hydrocarbon group substituted or unsubstituted with an oxygen atom, a nitrogen atom, a sulfur atom and having at least one aromatic ring, or CAn aliphatic hydrocarbon group of 6 to C17; r1 is a C2 to C18 aliphatic, alicyclic or aromatic group substituted or unsubstituted with a non-reactive oxygen, up to an average of 4 secondary or tertiary nitrogen atoms; r₂And R₃Each independently selected from H, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or R₂And R₃Bonded to each other to form a substituted or unsubstituted ring.

More specifically, the polyamine compound is at least one selected from the group consisting of m-xylylenediamine, 1, 3-bis (aminomethyl) cyclohexane, 2-methyl-1, 5-pentanediamine, 1, 3-pentanediamine, ethylenediamine, diethylenetriamine, triethylenetetramine, polypropylenediamine oxide, 2(4), 4-trimethyl-1, 6-hexanediamine, isophoronediamine, 2, 4-toluylenediamine, 1, 6-hexanediamine, 1, 2-diaminocyclohexane, and diaminodicyclohexylmethane (PACM).

In addition, optionally, an S400 capping step is further performed, in which the hardener (C) is reacted with the monofunctional epoxy compound at a temperature of 70 ℃ for 2 hours, then cooled to 60 ℃, and stirred and mixed with deionized water at a speed of 200rpm for 1 hour to obtain a hardener (D):

wherein RX is as shown (R0 and R5 are as described above), R1 is an aliphatic, alicyclic or aromatic group of C2 to C18 substituted or unsubstituted with a non-reactive oxygen, up to an average of 4 secondary or tertiary nitrogen atoms; r3 is at least one selected from the group consisting of branched or linear alkyl, alicyclic, polyoxyalkyl or alkenyl groups of 2-100 carbon atoms.

More specifically, the monofunctional epoxy compound may be an aliphatic, alicyclic or aromatic compound attached to the epoxy functional group as a terminal capping agent. Reacting the primary amine hydrogen reduces the chance of carbamate formation from atmospheric temperature reaction with the primary amine hydrogen. In addition to alleviating the blush phenomenon by reacting some or all of the primary amine groups consumed on the substituted aryl amidopolyamine, reacting the amidopolyamine with an epoxy functional group has the advantage of leaving a free amine hydrogen reactive with the epoxy group. Nevertheless, reacting the primary amine on the amidopolyamine compound with the epoxy functionality leaves behind a secondary amine hydrogen that is more reactive with the epoxy resin. Thus, the dual advantage is obtained of maintaining sufficient reactivity to cure the system without an extrinsic catalyst at room temperature while mitigating the whitening phenomenon. Reaction with monofunctional epoxy compounds also forms hydroxyl groups, which can also be used to react with the epoxy component.

The monofunctional epoxy compound is selected from the group consisting of 1, 2-hexeneoxide, 1, 2-heptenyloxy, isoheptenyloxy, 1, 2-octenyloxy, 1, 2-dodecenyloxy, 1, 2-pentadecenyloxy, butadiene monooxide, isoprene monooxide, styrenate, methyl glycidyl ether, ethyl glycidyl ether, phenyl glycidyl ether, n-butyl glycidyl ether, tolyl glycidyl ether, isopropyl glycidyl ether, benzyl glycidyl ether, glycidoxypropyltrimethoxysilane, octyl glycidyl ether, nonyl glycidyl ether, decyl glycidyl ether, dodecyl glycidyl ether, C12, C14 alkyl monoglycidyl ether, p-tert-butylphenyl glycidyl ether, and o-tolyl glycidyl ether.

First embodiment

100 g of polyethylene glycol PEG6000 and 5.3 g of methylhexahydrophthalic anhydride (MHHPA) were mixed under a nitrogen atmosphere and reacted at a temperature of 120 ℃ for 3 hours to cause esterification reaction, to obtain 105.3 g of an ester-based emulsifier (A).

105 g of the ester-based emulsifier (A) was mixed with 258 g of south Asia plastics to produce epoxy resin NPEL-136 to carry out a chain extension reaction, and reacted at a temperature of 120 ℃ for 1 hour and then at a temperature of 140 ℃ for 2 hours to obtain a polymer intermediate (B).

175 g of the polymer intermediate (B) was mixed with an excess of Diethylenetriamine (DETA) and reacted at a temperature of 70 ℃ for 4 hours to remove the excess DETA, to obtain a hardener (C).

Then adding 55.6 g of n-Butyl Glycidyl Ether (BGE) for end-capping reaction, reacting at 70 ℃ for 2 hours, cooling to 60 ℃, adding 280 g of deionized water, and stirring at a constant speed of 200rpm for 1 hour to obtain the hardener (D).

The hardener (D) obtained by the above reaction was further subjected to structural identification by NMR and FT-IR and spectroscopy, as shown in FIGS. 2 and 3.

Advantageous effects of the embodiments

One of the advantages of the present invention is that the hardener and the preparation method thereof provided by the present invention can provide a preparation method of the hardener without adding any additional volatile organic compound, prepare a water-compatible solvent-free hardener, and provide a hardened product with good performance through the step flow and the technical scheme of the specific ratio. The hardener provided by the invention has better compatibility with epoxy resin by virtue of the structure of bifunctional epoxy resin. The curing agent of the present invention can effectively cure the waterborne epoxy resin, and can be cured in a room temperature environment or at an elevated temperature. The aqueous epoxy resin may be, for example, an aqueous epoxy resin having a molecular weight of 350-.

The disclosure is only a preferred embodiment of the invention, and is not intended to limit the scope of the claims, so that all technical equivalents and modifications using the contents of the specification and drawings are included in the scope of the claims.