Water-borne epoxy resin modifier, preparation method thereof and water-borne epoxy resin emulsion

Abstract

The invention provides a water-borne epoxy resin modifier, a preparation method thereof and a water-borne epoxy resin emulsion, and belongs to the technical field of high polymer materials, and the preparation method specifically comprises the following steps: 1, reacting diisocyanate with methoxypolyethylene glycol according to a molar ratio of 1: (1-2) at the temperature of 30-50 DEG C to obtain a water-borne epoxy resin emulsion containing an isocyanate group at one end and an isocyanate group at the other end; a carbamate intermediate product with a methoxy group at one end; 2, the isocyanate group in the carbamate intermediate product reacts with hydroxyethyl acrylate at the temperature of 50-80 DEG C, a reaction product with one end containing a methoxy group and one end containing an acrylate product is obtained, and the reaction product is the water-borne epoxy resin modifier. By means of the treatment scheme, preparation is convenient, the stability of the waterborne epoxy resin emulsion can be improved, and large-scale production is easy.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a waterborne epoxy resin modifier and a preparation method thereof, and a waterborne epoxy resin emulsion. Background Art

[0002] Usually, epoxy resin molecules contain structures such as hydroxyl groups, ether bonds, benzene rings, and epoxy groups. By selecting different raw materials (such as different types of epoxy resins, curing agents, modifiers, etc.) and adjusting the formula and process parameters, epoxy resin curing products are given excellent physical and chemical properties through curing and cross-linking reactions, such as good mechanical properties, thermal stability, chemical stability, dimensional stability, and electrical insulation properties. Epoxy resin products with different performance characteristics can be prepared, so they are widely used in coatings, adhesives, electronic packaging materials, and other fields. However, most traditional epoxy resin products are organic solvent-based, which will release a large amount of volatile organic compounds (VOCs) during use, causing certain harm to the use environment and the health of construction workers. With the increasingly stringent environmental protection regulations, the development of water-based epoxy resins has become a research hotspot.

[0003] At present, the main methods for preparing waterborne epoxy resin emulsions include mechanical method, phase inversion method, chemical modification method and other preparation methods. Among them, the chemical modification method is to chemically modify the epoxy resin, usually by introducing hydrophilic groups (ionic or non-ionic) through grafting modification and esterification modification, so that it has self-emulsifying properties, so that it can spontaneously disperse in water to form a stable emulsion. Since the waterborne epoxy resin prepared by chemical modification has excellent performance, it is widely used in high-end coatings, electronic materials and other fields.

[0004] In the chemical modification method, the stability of ionic waterborne epoxy resin emulsions usually prepared by carboxylic acid modifiers is slightly better, but the film-forming products have technical problems such as poor water resistance. Non-ionic waterborne epoxy resins prepared by non-ionic modifiers are also sensitive to temperature. At higher temperatures, they may experience demulsification and stratification, which affects their performance. At the same time, their storage stability is limited: as the storage time increases, problems such as sedimentation and flocculation may occur, reducing the shelf life and reliability of the product. In addition, the coatings prepared by them also have technical problems such as insufficient hardness and poor adhesion. Summary of the invention

[0005] Therefore, in order to overcome the above-mentioned shortcomings of the prior art, the present invention provides a water-based epoxy resin modifier and a preparation method thereof, and a water-based epoxy resin emulsion, which are easy to prepare, can improve the stability of water-based epoxy resin emulsion, and are easy to mass produce.

[0006] In order to achieve the above object, the present invention provides a method for preparing a waterborne epoxy resin modifier, comprising: step 1, reacting diisocyanate with polyethylene glycol monomethyl ether at a molar ratio of 1:1-2 at a temperature of 30-50°C to obtain a carbamate intermediate product containing an isocyanate group at one end and a methoxy group at the other end; step 2, reacting the isocyanate group in the carbamate intermediate product with hydroxyethyl acrylate at a temperature of 50-80°C to obtain a reaction product containing a methoxy group at one end and an acrylate product at the other end, wherein the reaction product is a waterborne epoxy resin modifier, and the structural formula of the polyethylene glycol monomethyl ether is CH3O(C2H4O) n H, 1≤n≤100.

[0007] In one embodiment, the diisocyanate is at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and lysine diisocyanate.

[0008] In one embodiment, the molecular weight of the polyethylene glycol monomethyl ether is M, wherein the range of M is 200≤M≤5500.

[0009] In one embodiment, the molar ratio of polyethylene glycol monomethyl ether to diisocyanate is 1:1-1.5.

[0010] In one embodiment, the amount of the urethane intermediate and hydroxyethyl acrylate is selected according to the molar ratio of isocyanate group to hydroxyl group in the range of 1:1-2.

[0011] In one embodiment, the amount of the urethane intermediate and hydroxyethyl acrylate is selected according to the molar ratio of isocyanate group to hydroxyl group in the range of 1:1-1.5.

[0012] In one embodiment, the reaction temperature of step 1 is 30-40°C.

[0013] In one embodiment, the reaction temperature of step 2 is 50-60°C.

[0014] A waterborne epoxy resin modifier is prepared by the above method.

[0015] A water-based epoxy resin emulsion is prepared by using the water-based epoxy resin modifier.

[0016] Compared with the prior art, the advantages of the present invention are: using diisocyanate and polyethylene glycol monomethyl ether in precise proportion, the water-dispersible polyethylene glycol monomethyl ether is reacted with an isocyanate of diisocyanate by utilizing hydroxyl group, accessed into the diisocyanate structure, and then according to the precise proportion of stoichiometry, hydroxyethyl acrylate is added to prepare a water-based epoxy resin modifier. The water-based epoxy resin modifier combines the characteristics of non-ionic, has better hydrophilic and lipophilic properties, has better dispersibility and emulsification properties, makes its emulsion have higher stability, and is not prone to phenomena such as stratification and precipitation. The water-based epoxy resin modifier can be widely used in the technical field of preparation of coating emulsions for aircraft, ships, buildings, transportation and various mechanical equipment, and can meet the use requirements of water-based epoxy products. The whole preparation method has mild reaction, does not require pressure reaction equipment, has a simple preparation process, is easy to operate, is suitable for industrial production, and can be widely used in the preparation of protective coatings for aircraft, ships, buildings, transportation and various mechanical equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a simplified flow chart of the preparation method of the waterborne epoxy resin modifier in the embodiment of the present invention. DETAILED DESCRIPTION

[0019] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0020] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0021] It should be noted that various aspects of the embodiments within the scope of protection of the present invention are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0022] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0023] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0024] like Figure 1 As shown, the present invention provides a method for preparing a waterborne epoxy resin modifier, comprising the following steps:

[0025] Step 1, reacting diisocyanate with polyethylene glycol monomethyl ether at a molar ratio of 1:1-2 at a temperature of 30-50° C. to obtain a carbamate intermediate product containing an isocyanate group at one end and a methoxy group at the other end;

[0026] Step 2, the isocyanate group in the carbamate intermediate product reacts with hydroxyethyl acrylate at a temperature of 50-80° C. to obtain a reaction product containing a methoxy group at one end and an acrylate product at the other end, wherein the reaction product is a waterborne epoxy resin modifier.

[0027] The structural formula of polyethylene glycol monomethyl ether is CH3O(C2H4O) n H, 1≤n≤100.

[0028] The above-mentioned preparation method adopts diisocyanate and polyethylene glycol monomethyl ether of accurate proportion, and water-dispersible polyethylene glycol monomethyl ether is reacted with an isocyanate of hydroxyl and diisocyanate, and is connected to the diisocyanate structure, and then according to the accurate proportion of stoichiometry, hydroxyethyl acrylate is added to prepare water-based epoxy resin modifier. The water-based epoxy resin modifier combines the characteristics of non-ionic, and has better hydrophilic and lipophilic properties, has better dispersion and emulsification properties, makes its emulsion have higher stability, and is not prone to phenomena such as stratification and precipitation. The water-based epoxy resin modifier can be widely used in the technical field of preparation of coating emulsions for aircraft, ships, buildings, transportation and various mechanical equipment, and can meet the use requirements of water-based epoxy products. The whole preparation method has mild reaction, does not need pressure reaction equipment, and the preparation process is simple, easy to operate, suitable for industrial production, and can be widely used in the preparation of protective coatings for aircraft, ships, buildings, transportation and various mechanical equipment.

[0029] In one embodiment, the diisocyanate is at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, and lysine diisocyanate.

[0030] In one embodiment, the molecular weight of polyethylene glycol monomethyl ether is M, wherein the range of M is 200≤M≤5500; preferably 400≤M≤750.

[0031] In one embodiment, the molar ratio of polyethylene glycol monomethyl ether to diisocyanate is 1:1-1.5; more preferably, the molar ratio is 1:1-1.2.

[0032] In one embodiment, the amounts of the urethane intermediate and hydroxyethyl acrylate are selected in the range of 1:1-2 according to the molar ratio of isocyanate group to hydroxyl group.

[0033] In one embodiment, the amounts of the urethane intermediate and hydroxyethyl acrylate are selected according to a molar ratio of isocyanate group to hydroxyl group in the range of 1:1-1.5; more preferably, the molar ratio is 1:1-1.3; and even more preferably, the molar ratio is 1:1-1.2.

[0034] In one embodiment, the reaction temperature of step 1 is 30-40°C.

[0035] In one embodiment, the reaction temperature of step 2 is 50-60°C.

[0036] A water-based epoxy resin modifier is prepared by the above method. The water-based epoxy resin modifier combines the characteristics of non-ion, has better hydrophilic and lipophilic properties, has better dispersibility and emulsification properties, and makes its emulsion have higher stability and is not prone to stratification, precipitation and the like. The water-based epoxy resin modifier can be used to prepare water-based epoxy resin emulsion, does not contain organic solvents, is green and environmentally friendly. The prepared water-based epoxy resin has excellent adhesion and has good adhesion to a variety of substrates, such as metal, wood, concrete and the like.

[0037] A water-based epoxy resin emulsion is prepared by using the water-based epoxy resin modifier. The water-based epoxy resin emulsion has strong water resistance. After a special molecular structure design, the non-ionic water-based epoxy resin has excellent water resistance. When used for a long time in a humid environment or underwater, it can still maintain good performance and is not prone to bubbling, shedding and other problems.

[0038] Furthermore, the film-forming material of the waterborne epoxy resin emulsion prepared by the present invention has strong hardness, and the cured material of the non-ionic waterborne epoxy resin has excellent surface hardness through special molecular structure design.

[0039] In one embodiment, taking isophorone diisocyanate as an example, a method for preparing a waterborne epoxy resin modifier comprises the following steps:

[0040] Step 1: The diisocyanate is isophorone diisocyanate, and a carbamate-containing intermediate product A having an isocyanate group at one end and a methoxy group at the other end is obtained. The reaction equation is as follows:

[0041]

[0042] (Containing carbamate intermediate A)

[0043] Step 2, the isocyanate group of the carbamate intermediate product A reacts with hydroxyethyl acrylate at a temperature of 50-80° C. to obtain a reaction product B containing a methoxy group at one end and an acrylate product at the other end. The reaction product is a water-based epoxy resin modifier, and the reaction equation is as follows:

[0044]

[0045] The sources of the reagents and instruments used in the following examples are as follows:

[0046] Reagents and instruments used in the examples

[0047] Reagents / Instruments Purity / Model factory Isophorone diisocyanate CP Wuhan Fuxinyuan Technology Co., Ltd. Polyethylene glycol monomethyl ether MPEG400 CP / MPEG400 Jiangsu Haian Petrochemical Plant Polyethylene glycol monomethyl ether MPEG500 CP / MPEG500 Jiangsu Haian Petrochemical Plant Polyethylene glycol monomethyl ether MPEG750 CP / MPEG750 Jiangsu Haian Petrochemical Plant E20 Epoxy Resin CYD-011 Baling Petrochemical Epoxy Resin Factory Hydroxyethyl acrylate AR-level Shanghai Titan Technology Co., Ltd. Centrifuge Type 80-2B Changzhou Micono Instrument Co., Ltd. Pencil Hardness Tester QHQ-A type Shenzhen Lai Te Instrument Equipment Co., Ltd.

[0048] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] Example 1

[0050] Step 1: add 10g of isophorone diisocyanate (IPDI) to a 500mL four-necked flask equipped with a thermometer and a condenser, heat to 30°C under nitrogen protection, and start the stirrer; slowly add 18g of polyethylene glycol monomethyl ether MPEG400 from which water has been removed dropwise in four portions, and react for 1 hour; obtain a carbamate intermediate product A containing an isocyanate group at one end and a methoxy group at the other end;

[0051] Step 2: Add 5.2 g of hydroxyethyl acrylate into a flask, and slowly drop the carbamate intermediate product A obtained in step 1 into the flask. After the dropwise addition is completed, slowly increase the temperature to 40°C and continue the reaction for 2 hours to obtain a reaction product containing a methoxy group at one end and an acrylate product B at the other end.

[0052] Example 2

[0053] Step 1: Add 20g of isophorone diisocyanate (IPDI) into a 500mL four-necked flask equipped with a thermometer and a condenser, heat to 40°C under nitrogen protection, and start the stirrer; slowly add 45g of polyethylene glycol monomethyl ether MPEG500 from which water has been removed in four portions, and react for 1 hour; obtain a carbamate-containing intermediate product A containing an isocyanate group at one end and a methoxy group at the other end;

[0054] Step 2: Add 10.45 g of hydroxyethyl acrylate into a flask, and slowly drop the carbamate intermediate product A obtained in step 1 into the flask. After the dropwise addition is completed, slowly increase the temperature to 60°C and continue the reaction for 2 hours to obtain a reaction product containing a methoxy group at one end and an acrylate product B at the other end.

[0055] Example 3

[0056] Step 1: Add 15g of isophorone diisocyanate (IPDI) into a 500mL four-necked flask equipped with a thermometer and a condenser, heat to 40°C under nitrogen protection, and start the stirrer; slowly add 50.68g of polyethylene glycol monomethyl ether MPEG750 from which water has been removed dropwise in four portions, and react for 3 hours; obtain a carbamate-containing intermediate product A containing an isocyanate group at one end and a methoxy group at the other end;

[0057] Step 2: Add 7.89 g of hydroxyethyl acrylate into a flask, and slowly drop the carbamate intermediate product A obtained in step 1 into the flask. After the dropwise addition is completed, slowly increase the temperature to 60°C and continue the reaction for 2 hours to obtain a reaction product containing a methoxy group at one end and an acrylate product B at the other end.

[0058] Example 4

[0059] A certain amount of E20 epoxy resin was dissolved in propylene glycol methyl ether, placed in a 500 ml four-necked flask with a condenser and a N2 gas pipe, heated to 60°C, and a mixed solution prepared by the water-based epoxy resin modifier prepared in Example 1 and the initiator BPO (dibenzoyl peroxide) was added three times, once every 20 minutes. The temperature was raised to 85°C for reaction for three hours, the temperature was lowered, and a neutralizer and deionized water were added, and the mixture was stirred at high speed for 40 minutes to obtain a water-based epoxy resin emulsion.

[0060] Take 10mL of the prepared water-based epoxy resin emulsion and put it into the test tube of the 80-2B desktop centrifuge produced by Changzhou Mycono Instrument Co., Ltd. and carry out a centrifugal test. The speed is controlled at 1 000r / min. Observe whether the emulsion has stratification and demulsification, and record the corresponding time. It is found that no stratification occurs within the 162min of the investigation, indicating that the water-based epoxy resin has good storage stability.

[0061] The waterborne epoxy resin emulsion prepared above and the W061 curing agent provided by Shenzhen Winova Chemical Materials Co., Ltd. were fully stirred and mixed according to the ratio of their respective epoxy equivalents to active hydrogen equivalents, and cured to obtain a cured film.

[0062] According to GB / T1730-1993 standard, the coating hardness of the waterborne epoxy coating obtained above was tested using a QHQ-A coating pencil scratch hardness tester (Shenzhen Lai Te Instrument Equipment Co., Ltd.). The results showed that the coating hardness of the waterborne epoxy coating obtained was H.

[0063] The water resistance of the waterborne epoxy paint film obtained above was tested according to GB / T 1733-1993. The results showed that the water resistance of the obtained waterborne epoxy coating was greater than 7 days.

[0064] Example 5

[0065] A certain amount of E20 epoxy resin was dissolved in propylene glycol methyl ether, placed in a 500 ml four-necked flask with a condenser and a N2 gas pipe, heated to 70°C, and the mixed solution prepared by the water-based epoxy resin modifier and the initiator BPO prepared in Example 2 was added three times, once every 20 minutes. The temperature was raised to 85°C for reaction for three hours, the temperature was lowered, and a neutralizer and deionized water were added, and the mixture was stirred at high speed for 40 minutes to obtain a water-based epoxy resin emulsion.

[0066] Take 10mL of the prepared water-based epoxy resin emulsion and put it into the test tube of the 80-2B desktop centrifuge produced by Changzhou Mykono Instrument Co., Ltd. and carry out a centrifugal test. The speed is controlled at 1 000r / min. Observe whether the emulsion has stratification and demulsification, and record the corresponding time. It is found that no stratification occurs within the 187min of the investigation, indicating that the water-based epoxy resin has good storage stability.

[0067] The waterborne epoxy resin emulsion prepared above and the W061 curing agent provided by Shenzhen Winova Chemical Materials Co., Ltd. were fully stirred and mixed according to the ratio of their respective epoxy equivalents to active hydrogen equivalents, and cured to obtain a cured film.

[0068] According to GB / T1730-1993 standard, the coating hardness of the waterborne epoxy coating obtained above was tested using a QHQ-A coating pencil scratch hardness tester (Shenzhen Lai Te Instrument Equipment Co., Ltd.). The results showed that the coating hardness of the waterborne epoxy coating obtained was H.

[0069] The water resistance of the waterborne epoxy paint film obtained above was tested according to GB / T 1733-1993. The results showed that the water resistance of the obtained waterborne epoxy coating was greater than 7 days.

[0070] Example 6

[0071] A certain amount of E20 epoxy resin was dissolved in propylene glycol methyl ether, placed in a 500 ml four-necked flask with a condenser and a N2 gas pipe, heated to 80°C, and the mixed solution prepared by the water-based epoxy resin modifier and the initiator BPO prepared in Example 3 was added three times, once every 20 minutes. The temperature was raised to 85°C for reaction for three hours, the temperature was lowered, and a neutralizer and deionized water were added, and the mixture was stirred at high speed for 40 minutes to obtain a water-based epoxy resin emulsion.

[0072] Take 10mL of the prepared water-based epoxy resin emulsion and put it into the test tube of the 80-2B desktop centrifuge produced by Changzhou Mycono Instrument Co., Ltd. and carry out a centrifugal test. The speed is controlled at 1 000r / min. Observe whether the emulsion has stratification and demulsification, and record the corresponding time. It is found that no stratification occurs within the 205min of the investigation, indicating that the water-based epoxy resin has good storage stability.

[0073] The waterborne epoxy resin emulsion prepared above and the W061 curing agent provided by Shenzhen Winova Chemical Materials Co., Ltd. were fully stirred and mixed according to the ratio of their respective epoxy equivalents to active hydrogen equivalents, and cured to obtain a cured film.

[0074] According to GB / T1730-1993 standard, the coating hardness of the waterborne epoxy coating obtained above was tested using a QHQ-A coating pencil scratch hardness tester (Shenzhen Lai Te Instrument Equipment Co., Ltd.). The results showed that the coating hardness of the waterborne epoxy coating obtained was H.

[0075] The water resistance of the waterborne epoxy paint film obtained above was tested according to GB / T 1733-1993. The results showed that the water resistance of the obtained waterborne epoxy coating was greater than 7 days.

[0076] Comparative Example 1

[0077] A certain amount of E20 epoxy resin was dissolved in propylene glycol methyl ether, placed in a 500ml four-necked flask with a condenser and a N2 gas pipe, heated to 70°C, and a mixed solution made of methoxy polyethylene glycol acrylate with a molecular weight of 750g / mol and initiator BPO was added three times, once every 20 minutes. The temperature was raised to 85°C for three hours, the temperature was lowered, and a neutralizer and deionized water were added, and the mixture was stirred at high speed for 40 minutes to obtain a water-based epoxy resin emulsion.

[0078] Take 10mL of the prepared curing agent and put it into the test tube of the 80-2B desktop centrifuge produced by Changzhou Mykono Instrument Co., Ltd. and carry out a centrifugal test. The speed is controlled at 1,000r / min. Observe whether the emulsion has stratification and demulsification, and record the corresponding time. It is found that stratification occurs within 85 minutes of the observation, indicating that the storage stability of the water-based epoxy resin is poor.

[0079] The waterborne epoxy resin emulsion prepared above and the W061 curing agent provided by Shenzhen Winova Chemical Materials Co., Ltd. were fully stirred and mixed according to the ratio of their respective epoxy equivalents to active hydrogen equivalents, and cured to obtain a cured film.

[0080] According to GB / T1730-1993 standard, the film hardness of the waterborne epoxy coating obtained above was tested using a QHQ-A film pencil scratch hardness tester (Shenzhen Lai Te Instrument Equipment Co., Ltd.). The results showed that the film hardness of the waterborne epoxy coating obtained was B.

[0081] The water resistance of the waterborne epoxy paint film obtained above was tested according to GB / T 1733-1993. The results showed that the water resistance of the obtained waterborne epoxy coating was less than 7 days.

[0082] Comparative Example 2

[0083] A certain amount of E20 epoxy resin was dissolved in propylene glycol methyl ether, placed in a 500ml four-necked flask with a condenser and a N2 gas pipe, heated to 80°C, and a mixed solution made of methoxy polyethylene glycol acrylate with a molecular weight of 1000g / mol and initiator BPO was added three times, once every 20 minutes. The temperature was raised to 85°C for three hours, the temperature was lowered, and a neutralizer and deionized water were added, and the mixture was stirred at high speed for 40 minutes to obtain a water-based epoxy resin emulsion.

[0084] Take 10mL of the prepared curing agent and put it into the test tube of the 80-2B desktop centrifuge produced by Changzhou Mycono Instrument Co., Ltd. and carry out a centrifugal test. The speed is controlled at 1,000r / min. Observe whether the emulsion has stratification and demulsification, and record the corresponding time. It is found that stratification occurs within 73 minutes of the observation, indicating that the storage stability of the water-based epoxy resin is poor.

[0085] The waterborne epoxy resin emulsion prepared above and the W061 curing agent provided by Shenzhen Winova Chemical Materials Co., Ltd. were fully stirred and mixed according to the ratio of their respective epoxy equivalents to active hydrogen equivalents, and cured to obtain a cured film.

[0086] According to GB / T1730-1993 standard, the film hardness of the waterborne epoxy coating obtained above was tested using a QHQ-A film pencil scratch hardness tester (Shenzhen Lai Te Instrument Equipment Co., Ltd.). The results showed that the film hardness of the waterborne epoxy coating obtained was B.

[0087] The water resistance of the waterborne epoxy paint film obtained above was tested according to GB / T 1733-1993. The results showed that the water resistance of the obtained waterborne epoxy coating was less than 7 days.

[0088] Performance Test Table

[0089]

[0090] It can be seen from the above examples that the waterborne epoxy resin prepared by using the specific raw materials and process method of the present invention has more stable performance.

[0091] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed in the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a waterborne epoxy resin modifier, characterized in that: include: Step 1, reacting diisocyanate with polyethylene glycol monomethyl ether at a molar ratio of 1:1-2 at a temperature of 30-50° C. to obtain a carbamate intermediate product containing an isocyanate group at one end and a methoxy group at the other end; Step 2, the isocyanate group in the carbamate intermediate product reacts with hydroxyethyl acrylate at a temperature of 50-80° C. to obtain a reaction product containing a methoxy group at one end and an acrylate product at the other end, wherein the reaction product is a waterborne epoxy resin modifier. The structural formula of the polyethylene glycol monomethyl ether is CH3O(C2H4O) n H, 1≤n≤100.

2. The preparation method according to claim 1, characterized in that: The diisocyanate is at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and lysine diisocyanate.

3. The preparation method according to claim 1, characterized in that: The molecular weight of the polyethylene glycol monomethyl ether is M, wherein the range of M is 200≤M≤5500.

4. The preparation method according to claim 1, characterized in that: The molar ratio of the polyethylene glycol monomethyl ether to the diisocyanate is 1:1-1.

5.

5. The preparation method according to claim 1, characterized in that: The amounts of the urethane intermediate product and hydroxyethyl acrylate are selected in the range of 1:1-2 according to the molar ratio of isocyanate group to hydroxyl group.

6. The preparation method according to claim 5, characterized in that: The amounts of the urethane intermediate product and hydroxyethyl acrylate are selected according to the molar ratio of isocyanate group to hydroxyl group in the range of 1:1-1.

5.

7. The preparation method according to claim 1, characterized in that: The reaction temperature of step 1 is 30-40°C.

8. The preparation method according to claim 1, characterized in that: The reaction temperature of step 2 is 50-60°C.

9. A waterborne epoxy resin modifier, characterized in that: The waterborne epoxy resin modifier is prepared by the method according to any one of claims 1 to 8.

10. A water-based epoxy resin emulsion, characterized in that: The waterborne epoxy resin emulsion is prepared by using the waterborne epoxy resin modifier described in claim 9.

Images