Self-emulsifying waterborne epoxy resin curing agent, preparation method and application thereof

Abstract

The application discloses a self-emulsifying water-based epoxy resin curing agent and a preparation method and application thereof. The preparation method comprises the following steps: subjecting an organic amine to temperature treatment under a nitrogen atmosphere, then adding an epoxy resin, and continuously stirring and refluxing to react to obtain product I; adding pentaerythritol triacrylate into the product I, continuously keeping warm after dropwise adding to react, and obtaining product II; adding a capping agent into the product II, stirring to react, and obtaining the self-emulsifying water-based epoxy resin curing agent. The method is convenient to operate and reasonable in design. The curing agent has hydrophilic characteristics due to the introduction of the pentaerythritol triacrylate, and the curing agent has lipophilic characteristics due to the epoxy groups in the water-based epoxy resin, so that the self-emulsifying characteristics of the curing agent are effectively realized, the epoxy resin does not need to be added with an emulsifier in the use process, the curing agent prepared by the method has the characteristics of the emulsifier, the construction process is effectively simplified, and the operation is more convenient.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of epoxy resin curing agents, and relates to a self-emulsifying water-based epoxy resin curing agent and a preparation method and application thereof. BACKGROUND

[0002] Epoxy resin is active in the fields of coatings and adhesives due to its excellent bonding performance, mechanical performance, solvent resistance and corrosion resistance. However, epoxy resin itself does not have curing ability, and usually needs to be added with a curing agent or a catalyst to occur cross-linking reaction under certain conditions, so as to form a three-dimensional network structure of a polymer, and thus excellent performance can be exhibited. Therefore, the curing agent (catalyst) is an indispensable component of the epoxy resin. Before the existing curing agent is used, the epoxy resin must be mixed with an emulsifier, so that the epoxy resin forms a uniform and stable emulsion, and then the curing agent is added, so that the curing agent is cured to form a network structure, so that the use cost of the material is high, and the operation process is relatively complex. SUMMARY

[0003] In view of the problems in the prior art, the application provides a self-emulsifying water-based epoxy resin curing agent and a preparation method and application thereof, so as to solve the technical problem that the existing epoxy resin must be simultaneously added with a curing agent and an emulsifier during use, and thus the operation process is complex.

[0004] The application is achieved by the following technical scheme:

[0005] A preparation method of a self-emulsifying water-based epoxy resin curing agent, comprising the following steps:

[0006] S1: organic amine is subjected to temperature treatment under a nitrogen atmosphere, then epoxy resin is added, and reflux reaction is continued under stirring in a nitrogen atmosphere to obtain product I;

[0007] S2: pentaerythritol triacrylate is added to the product I, and after dropwise addition is completed, heat preservation reaction is continued to obtain product II;

[0008] S3: a capping agent is added to the product II, and stirring reaction is performed to obtain the self-emulsifying water-based epoxy resin curing agent.

[0009] Preferably, before the organic amine is subjected to temperature treatment under the nitrogen atmosphere in step S1, dehydration treatment is performed.

[0010] Preferably, in step S1, the molar ratio of the dehydrated organic amine to the epoxy resin is not less than 1.

[0011] Preferably, in step S1, the organic amine is one or more of ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine.

[0012] Preferably, in step S1, the adding rate of the epoxy resin is 0.01-0.05 mL / s.

[0013] Preferably, in step S2, the pentaerythritol triacrylate is diluted by propylene glycol methyl ether before being added into product I.

[0014] Preferably, in step S2, the pentaerythritol triacrylate is diluted by propylene glycol methyl ether to 0.2-0.5 g / mL.

[0015] Preferably, in step S2, the molar ratio of the pentaerythritol triacrylate to product I is (0.01-0.02):0.1.

[0016] A self-emulsifying waterborne epoxy resin curing agent prepared by the above method.

[0017] Application of the above self-emulsifying waterborne epoxy resin curing agent in the field of coatings.

[0018] Compared with the prior art, the present application has the following beneficial technical effects:

[0019] A preparation method of a self-emulsifying waterborne epoxy resin curing agent, by reacting an epoxy resin with an organic amine, introducing an epoxy resin segment into the curing agent, the epoxy groups on the epoxy resin make the curing agent have lipophilic properties, using the principle of similar solubility, the curing agent can be better dispersed in the epoxy resin, improving the compatibility of the curing agent and the epoxy resin. At the same time, the addition of pentaerythritol triacrylate makes the curing agent have excellent hydrophilic properties, effectively meeting the requirements of the curing agent as an emulsifier. In addition, the addition of pentaerythritol triacrylate also effectively increases the molecular weight of the curing agent, to further form a macromolecular network structure, making its curing performance better. Finally, the remaining organic amine is reacted with a blocking agent to terminate the reaction. The preparation method is convenient to operate and reasonable in design. The introduction of pentaerythritol triacrylate makes the curing agent have hydrophilic properties, and the epoxy groups in the waterborne epoxy resin make the curing agent have lipophilic properties, effectively realizing the self-emulsifying properties of the curing agent, so that the epoxy resin does not need to add an emulsifier during use. The curing agent prepared by the method also has the properties of an emulsifier, effectively simplifying the construction process and making the operation more convenient.

[0020] Further, the organic amine is subjected to dehydration treatment before being subjected to temperature treatment under a nitrogen atmosphere, because the presence of water will affect the actual weighing of the organic amine, and then affect the ratio of the actual added organic amine to the epoxy resin. At the same time, water will undergo ring-opening reaction with the epoxy groups in the epoxy resin, affecting the yield of the reaction.

[0021] Further, in step S1, the molar ratio of the dehydrated organic amine to the epoxy resin is not less than 1, because in the actual reaction process, when the molar ratio is less than 1, there is a lack of sufficient primary amine hydrogen to react with the epoxy group, which instead causes excessive epoxy groups to react with the terminal amine hydrogen of the intermediate product to form a high polymer, which is easy to cause gelation.

[0022] Further, in step S1, the addition rate of the epoxy resin is 0.01-0.05 mL / s, which can keep the organic amine in an excess state at all times, meeting the experimental requirements.

[0023] Further, in step S2, the pentaerythritol triacrylate is diluted by propylene glycol methyl ether before being added to the product I and diluted to 0.2-0.5 g / mL, because the pentaerythritol triacrylate is a multifunctional substance, and if it is added to the system at too high a speed and at too high a concentration, the epoxy resin will form a network structure in a short time, the curing speed will be fast, and the obtained coating will be brittle. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0025] Figure 1 The flowchart of the preparation method of the self-emulsifying waterborne epoxy resin curing agent of the present application;

[0026] Figure 2 The infrared spectrum of the self-emulsifying waterborne epoxy resin curing agent prepared in the present application;

[0027] Figure 3 The morphological characteristics of the waterborne epoxy resin coating prepared by adding the self-emulsifying waterborne epoxy resin curing agent prepared in embodiments 1-5 of the present application to the waterborne epoxy resin and curing; DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to understand the characteristics and effects of the present application, the following will make a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used in the text are the usual meanings understood by those skilled in the art for the present application, and in case of conflict, the definition in the specification shall prevail.

[0029] Theories or mechanisms described and disclosed herein, whether correct or not, should not be regarded as limiting the scope of the present application in any way, i.e., the content of the present application can be implemented without being limited by any particular theory or mechanism.

[0030] Herein, all features defined by a numerical range or a percentage range, such as numerical values, amounts, contents and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of a numerical range or a percentage range should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values (including integers and fractions) within the range.

[0031] Herein, unless otherwise specifically indicated, "comprise", "include", "contain", "have" or similar expressions are intended to encompass the meaning of "consist of" and "consist essentially of", for example, "A comprises a" encompasses the meaning of "A comprises a and other" and "A comprises only a".

[0032] Herein, for the sake of brevity of the description, all possible combinations of the technical features in the various embodiments or examples are not described. Therefore, the technical features in the various embodiments or examples can be combined in any manner as long as the combination does not contradict, and all possible combinations should be considered to be within the scope of the present specification.

[0033] Example 1

[0034] As Figure 1 described, the present application provides a preparation method of a self-emulsifying waterborne epoxy resin curing agent, comprising the following steps:

[0035] S1: after dehydration, the organic amine is heated to 75-80°C under nitrogen atmosphere, then the epoxy resin is added at a rate of 0.01-0.05 mL / s, and the product I is obtained by continuing to stir and reflux under nitrogen atmosphere; in this step, the organic amine is dehydrated because the presence of water will affect the actual weight of the organic amine, and then affect the actual ratio of the added organic amine to the epoxy resin. In this step, the reaction is carried out under nitrogen atmosphere because on the one hand, air contains a small amount of water, and organic amine is easy to absorb moisture, which affects the reaction of organic amine, so nitrogen is used to remove air, on the other hand, more importantly, water will have ring-opening reaction with epoxy groups in epoxy resin, which will affect the system. In this step, the dehydrated organic amine is heated to 75-80°C under nitrogen atmosphere, because in the actual experiment, it is found that when the temperature is low, the reaction rate is slow, and the reaction time is too long; when the temperature is too high, the reactivity of the secondary amine hydrogen increases, and the side reaction of the epoxy group with the secondary amine hydrogen occurs, which is easy to gel. Therefore, the suitable reaction temperature is selected to be 75-80°C. Among them, the molar ratio of the dehydrated organic amine to the epoxy resin is not less than 1; the organic amine is one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine.

[0036] S2: add propylene glycol methyl ether into pentaerythritol triacrylate, dilute pentaerythritol triacrylate with propylene glycol methyl ether to a concentration of 0.2-0.5 g / mL, then stir to mix uniformly, and slowly add into product I, continue to react after dropwise addition is completed, to obtain product II; in this step, pentaerythritol triacrylate is diluted by propylene glycol methyl ether, and propylene glycol methyl ether is used as a solvent to dilute pentaerythritol triacrylate; because pentaerythritol triacrylate is a multifunctional substance, if it is added too fast or at too high a concentration, the epoxy resin can form a network structure in a short time, the curing speed is fast, and the obtained coating is brittle. The molar ratio of pentaerythritol triacrylate to product I is (0.01-0.02):0.1.

[0037] S3: add a capping agent into product II, stir to react, to obtain the self-emulsifying waterborne epoxy resin curing agent. The capping agent can be hydroxypropyl acrylate and / or o-tolyl glycidyl ether, and the molar ratio of the capping agent to product II is (0.4-0.6):(0.8-1.2). Hydroxypropyl acrylate and / or o-tolyl glycidyl ether are used as a capping agent or a terminating agent, can react with primary amines, make the reaction of the system end-capped and terminated, and reduce the generation of by-products.

[0038] First, in order to improve the compatibility of the curing agent and the epoxy resin, the epoxy resin segment is introduced into the curing agent by reacting the waterborne epoxy resin with an organic amine, and the principle of similar solubility is used to make the epoxy resin added later better dispersed in the system. In order to increase the molecular weight and further form a macromolecular network structure, pentaerythritol triacrylate is added. Next, the remaining primary amines are capped with hydroxypropyl acrylate and o-tolyl glycidyl ether. Let the molecule reach a balance between hydrophilicity and lipophilicity, so that it has self-emulsifying properties.

[0039] The application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the application and not used to limit the scope of the application. Furthermore, it should be understood that after reading the content taught by the application, those skilled in the art can make various modifications or changes to the application, and these equivalent forms also fall within the scope defined by the appended claims of the application.

[0040] In the following examples, conventional instruments and equipment in the art are used. In the following examples, the experimental methods not specified in the specific conditions are usually carried out according to the conventional conditions or according to the conditions recommended by the manufacturers. In the following examples, various raw materials are used, unless otherwise specified, conventional commercially available products are used, and the specifications are conventional specifications in the art. In the specification of the application and the following examples, unless otherwise specified, “%” means weight percent, “parts” means weight parts, and the ratio means weight ratio.

[0041] Example 1

[0042] Accurately weigh 0.2 mol of dehydrated ethylenediamine and add it to a flask equipped with a temperature sensor, stirrer, and condenser. Under nitrogen protection, heat to 75°C, and then add 0.1 mol of epoxy resin E-51 dropwise over 2 hours. After the addition is complete, continue the reaction at this temperature for at least 1 hour to obtain product I.

[0043] 0.0167 mol of pentaerythritol triacrylate was diluted with 10 ml of propylene glycol methyl ether and slowly added dropwise over 1 hour to product I. After the addition was complete, the reaction was continued at this temperature for another 1 hour to obtain product II.

[0044] Add 0.5 mol of hydroxypropyl acrylate and react for 1 h to cap product II. Finally, add a certain amount of deionized water to adjust the solid content to 50% to obtain the target product.

[0045] Example 2

[0046] Accurately weigh 0.2 mol of dehydrated mixed amine (in which the molar ratio of ethylenediamine to tetraethylenepentamine is 0.15:0.05) and add it to a flask equipped with a temperature sensor, stirrer, and condenser. Under nitrogen protection, heat to 75°C, and then add 0.1 mol of epoxy resin E-51 dropwise over 2 hours. After the addition is complete, continue the reaction at this temperature for 1 hour to obtain product I.

[0047] Dilute 0.0167 mol of pentaerythritol triacrylate with 10 ml of propylene glycol methyl ether and slowly add it dropwise to product I over 1 hour. After the addition is complete, continue the reaction at this temperature for 1 hour to obtain product II.

[0048] Product II was capped by adding 0.5 mol of hydroxypropyl acrylate and reacting for 1 hour. Finally, a certain amount of deionized water was added to adjust the solid content to 50%, yielding the target product.

[0049] Example 3

[0050] Accurately weigh 0.2 mol of dehydrated mixed amine (ethylenediamine: tetraethylenepentamine = 0.10:0.10) and add it to a flask equipped with a temperature sensor, stirrer, and condenser. Under nitrogen protection, heat to 75°C, and then add 0.1 mol of epoxy resin dropwise over 2 hours. After the addition is complete, continue the reaction at this temperature for 1 hour to obtain product I.

[0051] Dilute 0.0167 mol of pentaerythritol triacrylate with 10 ml of propylene glycol methyl ether and slowly add it dropwise over 1 hour to product I. After the addition is complete, continue the reaction at this temperature for at least 1 hour to obtain product II.

[0052] Product II was capped by adding 0.5 mol of hydroxypropyl acrylate and reacting for 1 hour. Finally, a certain amount of deionized water was added to adjust the solid content to 50%, yielding the target product.

[0053] Example 4

[0054] Accurately weigh 0.2 mol of dehydrated mixed amine (ethylenediamine: tetraethylenepentamine = 0.05:0.15) into a flask equipped with a temperature sensor, a stirrer and a condenser. After warming up to 75°C under nitrogen, 0.1 mol of epoxy resin E-51 is added dropwise over 2 hours. After the addition is completed, the reaction is continued for 1 hour or more, to obtain product I.

[0055] Dilute 0.0167 mol of pentaerythritol triacrylate with 10 ml of propylene glycol methyl ether and slowly add it to product I over 1 hour. After the addition is completed, the reaction is continued for 1 hour or more, to obtain product II.

[0056] Cap product II by adding 0.5 mol of hydroxypropyl acrylate for 1 hour. Finally, add a certain amount of deionized water to adjust the solid content to 50%, to obtain the target product.

[0057] Example 5

[0058] Accurately weigh 0.2 mol of dehydrated tetraethylenepentamine into a flask equipped with a temperature sensor, a stirrer and a condenser. After warming up to 75°C under nitrogen, 0.1 mol of epoxy resin E-51 is added dropwise over 2 hours. After the addition is completed, the reaction is continued for 1 hour or more, to obtain product I.

[0059] Dilute 0.0167 mol of pentaerythritol triacrylate with 10 ml of propylene glycol methyl ether and slowly add it to product I over 1 hour. After the addition is completed, the reaction is continued for 1 hour or more, to obtain product II.

[0060] Cap product II by adding 0.5 mol of hydroxypropyl acrylate for 1 hour. Finally, add a certain amount of deionized water to adjust the solid content to 50%, to obtain the target product.

[0061] Example 6

[0062] Accurately weigh 0.2 mol of dehydrated mixed amine (ethylenediamine: tetraethylenepentamine = 0.1:0.1) into a flask equipped with a temperature sensor, a stirrer and a condenser. After warming up to 75°C under nitrogen, 0.1 mol of epoxy resin E-51 is added dropwise over 2 hours. After the addition is completed, the reaction is continued for 1 hour or more, to obtain product I.

[0063] Dilute 0.0167 mol of pentaerythritol triacrylate with 10 ml of propylene glycol methyl ether and slowly add it to product I over 1 hour. After the addition is completed, the reaction is continued for 1 hour or more, to obtain product II.

[0064] The product II is capped by adding a mixture of 0.4 mol of hydroxypropyl acrylate and 0.1 mol of o-tolyl glycidyl ether for 1 h. Finally, a certain amount of deionized water is added to adjust the solid content to 50%, obtaining the target product.

[0065] Example 7

[0066] Accurately weigh 0.2 mol of dehydrated mixed amine (ethylenediamine: tetraethylenepentamine = 0.1:0.1) into a flask equipped with a temperature sensor, stirring and a condenser. After warming up to 75°C under nitrogen protection, 0.1 mol of epoxy resin E-51 is added dropwise within 2 h. After the dropwise addition is completed, continue to heat for more than 1 h to obtain product I.

[0067] Dilute 0.0167 mol of pentaerythritol triacrylate with 10 ml of propylene glycol methyl ether and slowly add it to product I within 1 h. After the dropwise addition is completed, continue to heat for more than 1 h to obtain product II.

[0068] The product II is capped by adding a mixture of 0.3 mol of hydroxypropyl acrylate and 0.2 mol of o-tolyl glycidyl ether for 1 h. Finally, a certain amount of deionized water is added to adjust the solid content to 50%, obtaining the target product.

[0069] Example 8

[0070] Accurately weigh 0.2 mol of dehydrated mixed amine (ethylenediamine: tetraethylenepentamine = 0.1:0.1) into a flask equipped with a temperature sensor, stirring and a condenser. After warming up to 75°C under nitrogen protection, 0.1 mol of epoxy resin E-51 is added dropwise within 2 h. After the dropwise addition is completed, continue to heat for more than 1 h to obtain product I.

[0071] Dilute 0.0167 mol of pentaerythritol triacrylate with 10 ml of propylene glycol methyl ether and slowly add it to product I within 1 h. After the dropwise addition is completed, continue to heat for more than 1 h to obtain product II.

[0072] The product II is capped by adding a mixture of 0.2 mol of hydroxypropyl acrylate and 0.3 mol of o-tolyl glycidyl ether for 1 h. Finally, a certain amount of deionized water is added to adjust the solid content to 50%, obtaining the target product.

[0073] Example 9

[0074] Accurately weigh 0.2 mol of dehydrated mixed amine (ethylenediamine: tetraethylenepentamine = 0.1:0.1) into a flask equipped with a temperature sensor, stirring and a condenser. After warming up to 75°C under nitrogen protection, 0.1 mol of epoxy resin E-51 is added dropwise within 2 h. After the dropwise addition is completed, continue to heat for more than 1 h to obtain product I.

[0075] Dilute 0.0167 mol of pentaerythritol triacrylate with 10 ml of propylene glycol methyl ether and slowly add it dropwise over 1 hour to product I. After the addition is complete, continue the reaction at this temperature for at least 1 hour to obtain product II.

[0076] Product II was capped by reacting a mixture of 0.1 mol hydroxypropyl acrylate and 0.4 mol o-tolyl glycidyl ether for 1 h. Finally, a certain amount of deionized water was added to adjust the solid content to 50%, yielding the target product.

[0077] Example 10

[0078] Accurately weigh 0.2 mol of dehydrated mixed amine (ethylenediamine: tetraethylenepentamine = 0.1:0.1) and add it to a flask equipped with a temperature sensor, stirrer, and condenser. Under nitrogen protection, heat to 75°C, and then add 0.1 mol of epoxy resin E-51 dropwise over 2 hours. After the addition is complete, continue the reaction at this temperature for at least 1 hour to obtain product I.

[0079] Dilute 0.0167 mol of pentaerythritol triacrylate with 10 ml of propylene glycol methyl ether and slowly add it dropwise over 1 hour to product I. After the addition is complete, continue the reaction at this temperature for at least 1 hour to obtain product II.

[0080] Product II was capped by adding 0.5 mol of o-tolyl glycidyl ether and reacting for 1 h. Finally, a certain amount of deionized water was added to adjust the solid content to 50%, yielding the target product.

[0081] To characterize the successful preparation of this self-emulsifying waterborne epoxy resin curing agent, the target product obtained in Example 8 was subjected to Fourier transform infrared (FT-IR) testing, and the results are as follows: Figure 2 As shown, by Figure 2 It can be seen that the stretching vibration peaks of amine and hydroxyl groups in self-emulsifying waterborne epoxy resin curing agents are at 3480 cm⁻¹. -1 Location. 2930cm -1 A saturated -CH absorption peak appears at 1640 cm⁻¹. -1 The presence of a distinct -C=O absorption peak indicates that pentaerythritol triacrylate (PETA) and hydroxypropyl acrylate (HPA) have successfully added to the reaction product. However, no epoxy stretching vibration peak (915 cm⁻¹) was observed. -1 ) and bending vibration peak (759cm) -1 This indicates that the epoxy groups and amine groups have polymerized. Furthermore, 3005 cm⁻¹ -1 and 671cm -1 Characteristic absorption peaks related to the -CH group on the benzene ring were observed, as well as at 1243 cm⁻¹. -1 This is the COC absorption peak in epoxy E-51. In summary, this indicates that the epoxy resin has been added to the reaction products.

[0082] Further, in order to characterize the morphology of the coating after the self-emulsifying waterborne epoxy resin curing agent in the present application is added to the waterborne epoxy resin and cured, the target products in Examples 1-5 were subjected to cross-section scanning (SEM) morphology testing, and the results are shown in Figure 3 Figure 3 As can be clearly seen, with the increase of the amount of tetraethylenepentamine, the latex film is over from ductile fracture to brittle fracture. As can be seen from the SEM diagram, when the molar ratio of ethylenediamine to tetraethylenepentamine is 0.1:0.1, the cross section is the most compact, and there are almost no defects in the coating, only pores left by water vapor during the curing process. When the molar ratio of ethylenediamine to tetraethylenepentamine is 0:0.2, the latex particles formed by the emulsification of the epoxy resin by the self-emulsifying curing agent have strong reactivity between the curing agent component and the epoxy resin component inside the latex particles. The latex particles are not fully stretched and leveled, and are crosslinked inside the latex particles, so that the obvious latex particles can be observed.

[0083] Example 11

[0084] A preparation method of a self-emulsifying waterborne epoxy resin curing agent, comprising the following steps:

[0085] S1: After dehydration, diethylenetriamine is heated to 77℃ under a nitrogen atmosphere, then added to the epoxy resin at a rate of 0.01 mL / s, and the reaction is continued under stirring reflux in a nitrogen atmosphere to obtain product I; the molar ratio of the dehydrated organic amine to the epoxy resin is 1.

[0086] S2: Propylene glycol methyl ether is added to pentaerythritol triacrylate, and the pentaerythritol triacrylate is diluted with propylene glycol methyl ether to a concentration of 0.2 g / mL, then stirred and mixed uniformly, and slowly added to product I. After the dropwise addition is completed, the reaction is continued to obtain product II; wherein the molar ratio of pentaerythritol triacrylate to product I is 0.01:0.1.

[0087] S3: Hydroxypropyl acrylate is added to product II, and the reaction is stirred to obtain a self-emulsifying waterborne epoxy resin curing agent. The molar ratio of hydroxypropyl acrylate to product II is 0.5:0.8.

[0088] Example 12

[0089] A preparation method of a self-emulsifying waterborne epoxy resin curing agent, comprising the following steps:

[0090] S1: After dehydration, tetraethylenepentamine is heated to 79℃ under a nitrogen atmosphere, then added to the epoxy resin at a rate of 0.02 mL / s, and the reaction is continued under stirring reflux in a nitrogen atmosphere to obtain product I; the molar ratio of the dehydrated organic amine to the epoxy resin is 1.5.

[0091] ​S2: add propylene glycol methyl ether to pentaerythritol triacrylate, dilute pentaerythritol triacrylate with propylene glycol methyl ether to a concentration of 0.25 g / mL, then stir and mix uniformly, and slowly add to product I, continue to react after the dropwise addition is complete, to obtain product II; wherein the molar ratio of pentaerythritol triacrylate to product I is 0.02:0.1.

[0092] S3: add o-tolyl glycidyl ether to product II, stir and react to obtain a self-emulsifying waterborne epoxy resin curing agent. The molar ratio of o-tolyl glycidyl ether to product II is 0.4:0.9.

[0093] Example 13

[0094] A method for preparing a self-emulsifying waterborne epoxy resin curing agent, comprising the following steps:

[0095] S1: heat dehydrated tetraethylenepentamine and diethylenetriamine to 82°C under a nitrogen atmosphere, then add to the epoxy resin at a rate of 0.03 mL / s, continue to stir and reflux under a nitrogen atmosphere to obtain product I; the molar ratio of dehydrated organic amine to epoxy resin is 2.

[0096] S2: add propylene glycol methyl ether to pentaerythritol triacrylate, dilute pentaerythritol triacrylate with propylene glycol methyl ether to a concentration of 0.3 g / mL, then stir and mix uniformly, and slowly add to product I, continue to react after the dropwise addition is complete, to obtain product II; wherein the molar ratio of pentaerythritol triacrylate to product I is 0.015:0.1.

[0097] S3: add hydroxypropyl acrylate and o-tolyl glycidyl ether to product II, stir and react to obtain a self-emulsifying waterborne epoxy resin curing agent. The molar ratio of the sum of the molar amounts of hydroxypropyl acrylate and o-tolyl glycidyl ether to product II is 0.6:1.2.

[0098] Example 14

[0099] A method for preparing a self-emulsifying waterborne epoxy resin curing agent, comprising the following steps:

[0100] S1: heat dehydrated ethylenediamine and triethylenetetramine to 85°C under a nitrogen atmosphere, then add to the epoxy resin at a rate of 0.05 mL / s, continue to stir and reflux under a nitrogen atmosphere to obtain product I; the molar ratio of dehydrated organic amine to epoxy resin is 2.2.

[0101] S2: add propylene glycol methyl ether into pentaerythritol triacrylate, dilute the pentaerythritol triacrylate with propylene glycol methyl ether to a concentration of 0.35 g / mL, then stir and mix uniformly, and slowly add into product I, continue to react after the dropwise addition is completed, to obtain product II; wherein the molar ratio of pentaerythritol triacrylate to product I is 0.02:0.1.

[0102] S3: add hydroxypropyl acrylate and o-tolyl glycidyl ether into product II, stir and react, to obtain a self-emulsifying waterborne epoxy resin curing agent. The molar ratio of the sum of the molar amounts of hydroxypropyl acrylate and o-tolyl glycidyl ether to product II is 0.5:1.1.

[0103] The above only describes the preferred embodiments of the present application, and it should be noted that those of ordinary skill in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

[0104] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application.

Claims

1. A method for preparing a self-emulsifying waterborne epoxy resin curing agent, characterized by, It comprises the following steps: S1: after the organic amine is dehydrated, it is heated to 75-80℃ under nitrogen atmosphere, then the epoxy resin is added at a rate of 0.01-0.05 mL / s, wherein the molar ratio of the dehydrated organic amine to the epoxy resin is not less than 1, and the product I is obtained by continuing to stir and reflux under nitrogen atmosphere; the organic amine is a mixed amine of ethylenediamine and tetraethylenepentamine, and the molar ratio of the ethylenediamine to the tetraethylenepentamine is 0.1:0.1; S2: after the pentaerythritol triacrylate is diluted to 0.2-0.5 g / mL with propylene glycol methyl ether, it is added dropwise into the product I, the molar ratio of the pentaerythritol triacrylate to the product I is (0.01-0.02):0.1, and after the addition is completed, the reaction is continued to obtain the product II; S3: the capping agent is added into the product II, and the self-emulsifying waterborne epoxy resin curing agent is obtained by stirring and reacting.

2. A self-emulsifying waterborne epoxy resin curing agent characterized by comprising: It is prepared by the method in claim 1.

3. The use of the self-emulsifying waterborne epoxy resin curing agent in claim 2 in the field of coatings.

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