A hydrophilic imide resin and its preparation method

Abstract

This invention provides a hydrophilic imide resin and its preparation method, relating to the field of amino resin technology. The hydrophilic imide resin has the structure YA2, where Y is a divalent organic structure with an average molecular weight of 50-5000, remaining after removing two terminal primary amino groups from a bipolar primary amine polyether. This structure is reactively inert to isocyanate groups at 100°C. The bipolar primary amine polyether has a solubility in pure water of not less than 10 g / 100 g water at 25°C. The structure A is formed by two ester groups in an aspartic acid ester resin forming one imide structure, or four ester groups forming two imide structures, or a combination thereof. The hydrophilic imide resin of this invention exhibits good hydrophilicity, good hydrolysis resistance, and high mechanical strength after curing.

Description

Technical Field

[0001] This invention belongs to the field of amino resin technology and relates to a hydrophilic imide resin and its preparation method. Background Technology

[0002] Aspartic resins are typically obtained through a Michael addition reaction between dialkyl maleate esters (such as diethyl maleate) and polyamine compounds, followed by curing with isocyanate curing agents to form third-generation polyureas—aspartic polyureas. The ester groups in the dialkyl maleate ester act as solubilizers and internal plasticizers in the polyurea. For hydrophilic aspartic resins, transesterification between hydrophilic polyethers and ester groups is generally used. However, due to the poor hydrolysis resistance of ester bonds, hydrophilic aspartic resins often lack sufficient hydrolysis resistance. Over time, hydrolysis of the ester bonds causes the hydrophilic polyether segments to detach from the aspartic resin, resulting in the loss of hydrophilicity and affecting product performance.

[0003] Therefore, it is necessary to modify the existing technology to further improve the hydrolysis resistance of hydrophilic aspartic resin. Summary of the Invention

[0004] Imine structures possess good heat resistance, hydrolysis resistance, and chemical resistance. Modification methods for imides typically involve grafting different organic groups onto the nitrogen atom (N) to provide different properties. For example, introducing a hydrophilic polyether structure onto the N atom of an imide can improve its hydrophilicity and provide good stability, making it less prone to hydrolysis that could lead to performance degradation or failure. However, existing technologies use maleimide or substituted maleimide to undergo a Michael addition reaction with polyamine compounds to obtain imide resins, requiring the use of polyethers to replace maleimide, where the carbon-carbon double bond has low reactivity. The inventors have conducted in-depth research and analysis on this issue. Based on this, the present invention provides a hydrophilic imide resin and its preparation method.

[0005] The technical solution of the present invention is as follows:

[0006] A hydrophilic imide resin has the structure shown in formula (1).

[0007] YA2(1)

[0008] Wherein, Y is a divalent organic structure with an average molecular weight of 50-5000 remaining after removing two terminal primary amino groups from a bipolar primary amine polyether, which is reactively inert to isocyanate groups at 100℃. The bipolar primary amine polyether has a solubility in pure water of not less than 10g / 100g water at 25℃. The structure of A is shown in formula (2) or (3) below, or the structure of A is a combination of the structures shown in formula (2) and formula (3).

[0009]

[0010] Among them, R 1 and R 2 Individually selected from C1-C4 alkyl groups, R 3 Selected from C1-C18 alkyl, C2-C18 substituted alkyl or polyether segments, where X is a divalent organic structure with an average molecular weight of 50-500 that is reactive with isocyanate groups at 100°C after the removal of the primary amino group from a polyamine compound.

[0011] Preferably, the number average molecular weight of the dual-terminated primary amine polyether does not exceed 2500.

[0012] More preferably, the molar ratio of Equation (2) and Equation (3) in the combination of the structures shown in Equation (2) and Equation (3) is 1:4-4:1.

[0013] Preferably, the structure of the polyether segment is shown in formula (4).

[0014] -(CH2CH2O) m (CH2CHCH3O) n R 4 (4)

[0015] Where m≥0, n≥0, 1≤m+n≤50, R 4 Selected from H or C1-C18 alkyl groups.

[0016] More preferably, m ≥ 1.2n, R 4 Selected from C4-C18 alkyl groups.

[0017] More preferably, m < 1.2n, R 4 Selected from H or C1-C4 alkyl groups.

[0018] A method for preparing the hydrophilic imide resin according to any of the above technical solutions includes the following steps:

[0019] The polyamine compound and the alkyl maleate ester undergo a Michael addition reaction to obtain the first acepartic resin;

[0020] The first aspartic resin undergoes a first imide reaction with the double-terminated primary amine polyether to obtain the hydrophilic imide resin;

[0021] Alternatively, the first aspartic resin reacts with the bi-terminated primary amine polyether to undergo a second imide reaction, and then the R is added. 3 The corresponding monoamine compound R 3 NH2 is used to carry out a third imide reaction to obtain the hydrophilic imide resin; R 3 The meaning of is as described above.

[0022] Preferably, the catalysts for the first imide reaction, the second imide reaction, and the third imide reaction are individually selected from one or a combination of two or more of C6-C18 fatty acids, benzotriazoles, and substituted benzotriazoles.

[0023] Preferably, the molar ratio of the first aspartic resin to the dual-terminated primary amine polyether is 1.8-2.2:1.

[0024] Preferably, the molar ratio of the first aspartic resin to the monoamine compound is 1:0.2-1.

[0025] The beneficial effects of this invention are:

[0026] (1) In this invention, the connection between the hydrophilic polyether and the aspartic resin adopts an imide structure, which improves the hydrolysis resistance of the resin. Moreover, the hydrophilic polyether is in the middle of the resin structure, and the two ends are aspartic resin structures. The resulting imide resin has good hydrophilicity and can further undergo a curing reaction with the curing agent.

[0027] (2) The ester groups in the imide resin of the present invention can undergo further imide reactions, and the imide resin may be essentially free of ester groups. The cured imide resin exhibits significantly improved heat resistance, hydrolysis resistance, and mechanical strength. Moreover, the preparation process is relatively simple, and the raw materials are readily available, allowing for flexible resin structure design. Detailed Implementation

[0028] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0029] To address the shortcomings of existing hydrophilic aspartic resins, such as inflexible structural design, poor hydrolysis resistance, insufficient heat resistance, and low mechanical strength, and to avoid the low reactivity problem caused by directly using polyether-substituted maleimides, this invention proposes a hydrophilic imide resin with the structure shown in formula (1).

[0030] YA2(1)

[0031] Wherein, Y is a divalent organic structure with an average molecular weight of 50-5000, which is reactive with isocyanate groups at 100℃ after the removal of two terminal primary amino groups from the bipolar primary amino polyether. The solubility of the bipolar primary amino polyether in pure water at 25℃ is not less than 10g / 100g water. The structure of A is shown in formula (2) or (3) below, or the structure of A is a combination of the structures shown in formula (2) and formula (3).

[0032]

[0033] Among them, R 1 and R 2Individually selected from C1-C4 alkyl groups, R 3 Selected from C1-C18 alkyl, C2-C18 substituted alkyl or polyether segments, where X is a divalent organic structure with an average molecular weight of 50-500 that is reactive with isocyanate groups at 100°C after the removal of the primary amino group from a polyamine compound.

[0034] In the hydrophilic imide resin structure of this invention, the middle part is a hydrophilic polyether structure, and the two ends are aspartic resin structures. The hydrophilic imide resin structure contains two secondary amine groups, which can undergo a curing reaction with isocyanate curing agents. Moreover, even if the hydrophilic imide resin of this invention contains ester groups and the ester groups undergo hydrolysis, it will not affect the connection structure between the hydrophilic polyether and the main chain, resulting in good stability. The hydrophilic imide resin of this invention can also further imidize the ester groups at the end groups to further improve properties such as hydrolysis resistance, heat resistance, and mechanical strength.

[0035] Specifically, in this invention, R 1 and R 2 It can be ethyl alone, R 3 It can be ethyl, n-butyl, n-hexyl, n-octyl, isooctyl, N,N-dimethyl-3-aminopropyl, N,N-dimethyl-4-aminobutyl, etc.; R 3 It can also be a polyether segment, which can be a monovalent polyethylene glycol / polypropylene glycol structure, a monovalent polypropylene glycol structure, etc. Therefore, in this invention, through the Y structure and R... 3 By adjusting the structure, a variety of imide resins with different structures can be obtained, making the structure more flexible.

[0036] Preferably, the solubility of the bipolar primary amine polyether in pure water at 25°C is not less than 30 g / 100 g water. For example, the solubility can be any value among 30 g / 100 g water, 50 g / 100 g water, 80 g / 100 g water, 100 g / 100 g water, 120 g / 100 g water, 130 g / 100 g water, 150 g / 100 g water, 180 g / 100 g water, and 200 g / 100 g water, without any particular limitation. Higher solubility of the bipolar primary amine polyether indicates better hydrophilicity. Specifically, the bipolar primary amine polyether can be bipolar primary amine polyethylene glycol or bipolar primary amine polyethylene glycol / polypropylene glycol copolymer, which can be purchased directly from the market, such as ZED-901, ZED-601, and ZED-2031 from Zibo Zhengda Polyurethane Co., Ltd.

[0037] In a preferred embodiment of the present invention, the number average molecular weight of the bi-terminated primary amine polyether does not exceed 2500. If the number average molecular weight of the bi-terminated primary amine polyether is too high, the activity of the bi-terminated primary amine groups will be low, leading to a slower or incomplete imide reaction. If the number average molecular weight of the bi-terminated primary amine polyether does not exceed 2500, the activity of the bi-terminated primary amine groups is higher, allowing the imide reaction to proceed more quickly and completely.

[0038] In a more preferred embodiment of the present invention, the molar ratio of formulas (2) and (3) in the combination of structures shown in formulas (2) and (3) is 1:4 to 4:1. Using the above technical solution, the structural design of the imide resin is more flexible. For example, the molar ratio of the structures in formulas (2) and (3) can be any value among 1:4, 1:3, 1:2, 1:1, 1:2, 1:3, 1:4, etc., without any particular limitation.

[0039] In a preferred embodiment of the present invention, the structure of the polyether segment is shown in formula (4).

[0040] -(CH2CH2O) m (CH2CHCH3O) n R 4 (4)

[0041] Where m≥0, n≥0, 1≤m+n≤50, R 4 Selected from H or C1-C18 alkyl groups. The molecular weight and hydrophilicity / hydrophobicity of the polyether segments in the above structure can be adjusted by changing the values ​​of m and n. The corresponding amino polyethers can be purchased directly from the market, such as ZM-1100 and ZM-160 from Zibo Zhengda Polyurethane Co., Ltd.

[0042] In a more preferred embodiment of the present invention, m ≥ 1.2n, R 4 Selected from C4-C18 alkyl groups. When n ≥ 1.2m, the polyether segment has strong hydrophilicity, which can be increased by adding R. 4 The hydrophobicity is adjusted to control the hydrophilicity / hydrophobicity of the polyether segments. For example, m = 1.2n, m = 1.5n, m = 2n, m = 2.5n, m = 3n, etc., R 4 It can be n-butyl, n-hexyl, n-octyl, lauryl, stearyl, etc.

[0043] In a more preferred embodiment of the present invention, m < 1.2n, R 4 Selected from H or C1-C4 alkyl groups. When 0.5n ≤ m < 1.2n, the polyether segments are more hydrophobic, which can be mitigated by reducing R... 4 The hydrophobicity is adjusted to control the hydrophilicity / hydrophobicity of the polyether segments. Examples include m = 0.5n, m = 0.6n, m = 0.7n, m = 0.8n, m = 0.9n, m = n, m = 1.1n, etc., R 4It can be methyl, ethyl, isopropyl, etc.

[0044] On the other hand, the present invention provides a method for preparing the hydrophilic imide resin described in any of the above technical solutions, comprising the following steps:

[0045] A polyamine compound and an alkyl maleate ester undergo a Michael addition reaction to obtain an acepartic resin.

[0046] The first acetone resin was reacted with a double-terminated primary amine polyether to obtain a hydrophilic imide resin by a first imide reaction.

[0047] Alternatively, the first acetone resin undergoes a second imide reaction with a bi-terminated primary amine polyether, followed by the addition of R. 3 The corresponding monoamine compound R 3 NH2 undergoes a third imide reaction to obtain a hydrophilic imide resin; R 3 The meaning of is as described above.

[0048] The method described above in this invention can be used to prepare hydrophilic imide resins. The first aspartic resin can be a commercially available aspartic resin, such as F420 or F520 resin from Shenzhen Feiyang Junyan New Materials Co., Ltd. Therefore, in this invention, commercially available aspartic resin products can be directly used, and the hydrophilic imide resin of this invention can be obtained through a single imide reaction, or through two imide reactions. The reaction steps are short and the operation is simple. In the above-described first, second, and third imide reactions, the generated alcohols (such as ethanol and methanol) can be continuously removed by distillation or gas purification (such as introducing nitrogen gas) to facilitate the complete imide reaction.

[0049] In a preferred embodiment of the present invention, the catalysts for the first, second, and third imide reactions are individually selected from one or a combination of two or more of C6-C18 fatty acids, benzotriazoles, and substituted benzotriazoles. Adding a catalyst to the imide reaction can increase the reaction rate and promote a more complete reaction. For example, the catalyst can be stearic acid, lauric acid, 1-octanoic acid, 1-hydroxybenzotriazole, etc. The amount of catalyst can be 0.1-0.5% of the weight of the aspartic resin; for example, it can be any value selected from 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc., without particular limitation.

[0050] Specifically, in the above preparation method of the present invention, the first imide reaction can be carried out as follows: a catalyst is added to the first acetone resin, the temperature is raised to 90-150°C, then a double-terminated primary amine polyether is added, and the reaction is continued until reflux occurs in the reaction system. The alcohol produced is removed by distillation or nitrogen purging until no bubbles are generated in the reaction system, thus obtaining the hydrophilic imide resin. Alternatively, a monoamine compound is added to the hydrophilic imide resin obtained above to carry out a second imide reaction, and the alcohol produced is again removed by distillation or nitrogen purging and the reaction is continued until no bubbles are generated in the system, thus obtaining the hydrophilic imide resin.

[0051] In a preferred embodiment of the present invention, the molar ratio of acepartic resin to diamino-terminated polyether is 1.8-2.2:1. From the perspective of the reactants and products, a molar ratio of acepartic resin to diamino-terminated polyether of 2:1 is sufficient for the reaction to proceed. When the molar ratio deviates from 2:1, for example, if acepartic resin is in excess or insufficient, both reactants will not fully participate in the reaction. In this case, unreacted reactants can be removed by separation or precipitation to obtain the desired product, which is industrially feasible. However, from an industrial production perspective, a more suitable molar ratio of acepartic resin to diamino-terminated polyether is 1.9-2.1:1. In this case, the reaction product can be used directly without further separation or purification, although further separation or purification can be performed if necessary. Alternatively, the molar ratio of the first primary acetone resin to the dual-terminated primary amine polyether can be 1.95-2.1:1. For example, the molar ratio can be any value among 1.95:1, 1.97:1, 1.99:1, 2:1, 2.01:1, 2.03:1, 2.05:1, 2.08:1, 2.1:1, etc., without any particular restrictions.

[0052] In a preferred embodiment of the present invention, the molar ratio of the first acepartic resin to the monoamine compound is 1:0.2-1. The above technical solution allows for adjustment of the proportion of ester groups substituted in the first acepartic resin. For example, the molar ratio of the first acepartic resin to the monoamine compound can be any value from 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6, 1:0.65, 1:0.7, 1:0.75, 1:0.8, 1:0.85, 1:0.9, 1:0.95, 1:1, etc., without particular limitation.

[0053] The technical solution of the present invention will be further described and illustrated below with reference to various embodiments. Unless otherwise specified, the parts mentioned in the following embodiments are parts by weight.

[0054] Example 1

[0055] 1 mol of commercially available F420 resin (Feiyang Junyan Company) was added to a container, along with 0.25% by weight of 1-hydroxybenzotriazole catalyst. The mixture was heated to 120°C, and 0.5 mol of bi-terminated primary amine polyethylene glycol (number average molecular weight 1100) was added. The mixture was stirred until reflux occurred in the reaction system. Nitrogen gas was continuously purged to remove the generated ethanol until no more bubbles were generated in the reaction system. The resulting hydrophilic imide resin was a light yellow and transparent substance.

[0056] According to the structure of formula (1) above, the structure of the hydrophilic imide resin in this embodiment is as follows: Y is the divalent polyether structure remaining after removing two primary amino groups from bi-terminated primary amino polyethylene glycol, A is the structure shown in formula (2), and R... 1 and R 2 All are ethyl groups, and X is the divalent structure remaining after removing two primary amino groups from 4,4'-diaminodicyclohexylmethane.

[0057] Example 2

[0058] In Example 1, after no more bubbles were generated in the reaction system, 0.25 mol of n-hexylamine was added, and the reaction was continued at a constant temperature of 120°C. The mixture was stirred until reflux occurred in the reaction system, and nitrogen gas was passed through to remove the generated ethanol until no more bubbles were generated in the reaction system, thus obtaining a hydrophilic imide resin, which is brownish-yellow and transparent.

[0059] According to the structure of formula (1) above, the structure of the hydrophilic imide resin in this embodiment is as follows: Y is the divalent polyether structure remaining after removing two primary amino groups from bi-terminated primary amino polyethylene glycol, A is a combination of the structures shown in formula (2) and formula (3) in a molar ratio of 3:1, R 1 and R 2 Both are ethyl, R 3 X is n-hexyl, and X is the divalent structure remaining after removing two primary amino groups from 4,4'-diaminodicyclohexylmethane.

[0060] Example 3

[0061] The difference between Example 3 and Example 2 is that in Example 2, the amount of n-hexylamine was adjusted from 0.25 mol to 0.6 mol. The remaining steps remained unchanged. The resulting hydrophilic imide resin was a brownish-yellow transparent substance.

[0062] Example 4

[0063] The difference between Example 4 and Example 2 is that in Example 2, the amount of n-hexylamine was adjusted from 0.25 mol to 1 mol. All other steps remained unchanged. The resulting hydrophilic imide resin was a brownish-yellow transparent substance.

[0064] Example 5

[0065] The difference between Example 5 and Example 3 is that in Example 3, hexylamine was replaced with an equimolar amount of single-terminated amino polyether ZM-160. The remaining steps remained unchanged. The resulting hydrophilic imide resin was a brownish-yellow transparent substance.

[0066] Example 6

[0067] The difference between Example 6 and Example 4 is that in Example 4, hexylamine was replaced with an equimolar amount of single-terminated amino polyether ZM-160. The remaining steps remained unchanged. The resulting hydrophilic imide resin was a brownish-yellow transparent color.

[0068] Example 7

[0069] The difference between Example 7 and Example 5 is that in Example 5, ZM-160 was replaced with an equimolar amount of CAM-2070 (Chenhua Chemical). The remaining steps remained unchanged. The resulting hydrophilic imide resin was a brownish-yellow transparent color.

[0070] Example 8

[0071] 1.95 mol of commercially available F520 resin (Feiyang Junyan Company) was added to a container, along with 0.3% by weight of 1-hydroxybenzotriazole catalyst. The mixture was heated to 130°C, and 1 mol of ZED-901 amino-terminated polyether (Zibo Zhengda Polyurethane Company) was added. The mixture was stirred until reflux occurred in the reaction system. Nitrogen gas was continuously purged to remove the generated ethanol until no more bubbles were generated in the reaction system. The resulting hydrophilic imide resin was a light yellow and transparent substance.

[0072] Example 9

[0073] The difference between Example 9 and Example 8 is that in Example 8, the amount of F520 resin was adjusted from 1.95 mol to 2.02 mol. The remaining steps remained unchanged. The resulting hydrophilic imide resin was a brownish-yellow transparent substance.

[0074] Example 10

[0075] The difference between Example 10 and Example 8 is that in Example 8, the amount of F520 resin was adjusted from 1.95 mol to 2.1 mol. The remaining steps remained unchanged. The resulting hydrophilic imide resin was a brownish-yellow transparent substance.

[0076] Comparative Example 1

[0077] Hydrophilic polyaspartic acid ester resin was prepared according to the method of Example 1 in the prior art CN111303368A.

[0078] Test method for water solubility of the resin: At 25℃, weigh 100g of the resin sample and place it in a colorless, transparent container. Slowly add an appropriate amount of pure water while stirring, and stir until homogeneous. Then, perform the test according to the method specified in GB 1721-2008 "Determination of Appearance and Transparency of Varnishes, Oils and Diluents". Record the weight of pure water added when the instrument reading reaches 82. The results are shown in Table 1 below. The less pure water is used, the worse the hydrophilicity of the resin.

[0079] The resin to be tested and the isocyanate curing agent (composed of an adduct curing agent prepared from 3% HDI trimer, 10% HMDI, and 87% IPDI with polyether polyol) were mixed uniformly at a ratio of 1:1.05 of the total molar number of secondary amine and hydroxyl groups to the molar number of isocyanate groups to obtain a coating composition. A film with a thickness of 0.1 mm was formed on a clean glass surface and placed at 25°C and 55% humidity for 24 hours. The boiling time in a 1wt% NaOH aqueous solution at 100°C was then tested, with observations every 0.5 hours. The boiling time was defined as the time closest to the appearance of abnormalities such as film peeling, curling, or blistering. For example, if abnormalities were observed after 3.5 hours, the boiling time was 3 hours. A longer boiling time indicates better hydrolysis resistance.

[0080] The above coating composition forms a film of 0.5 mm, is cured at 35±2℃ for 15 days, and its tensile strength is tested.

[0081] The results are shown in Table 1 below.

[0082] Table 1

[0083]

[0084]

[0085] As can be seen from the data results in Table 1 above, the hydrophilic imide resin of the present invention has good hydrophilicity, hydrolysis resistance and mechanical strength. Moreover, by adjusting the double-terminated primary amine polyether and / or monoamine compound used, the structure and properties of the obtained imide resin can be flexibly adjusted.

[0086] As described above, the basic principles, main features, and advantages of the present invention have been shown and described. Those skilled in the art should understand that the present invention is not limited to the above embodiments, which are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent changes and modifications made in accordance with the scope of the patent and the description should still fall within the scope of the present invention. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A hydrophilic imide resin, characterized in that, It has the structure shown in equation (1) below. YA2(1) Wherein, Y is a divalent organic structure with an average molecular weight of 50-5000, which is reactive with isocyanate groups at 100℃ after the removal of two terminal primary amino groups from the bipolar primary amino polyether. The bipolar primary amino polyether has a solubility in pure water at 25℃ of not less than 10g / 100g water. The structure of A is shown in formula (2) or formula (3) below, or the structure of A is a combination of the structures shown in formula (2) and formula (3). （2） （3） Among them, R 1 and R 2 Individually selected from C1-C4 alkyl groups, R 3 Selected from C1-C18 alkyl, C2-C18 substituted alkyl or polyether segments, where X is a divalent organic structure with an average molecular weight of 50-500 that is reactive with isocyanate groups at 100°C after the removal of the primary amino group from a polyamine compound.

2. The hydrophilic imide resin according to claim 1, characterized in that, The number average molecular weight of the dual-terminated primary amino polyether does not exceed 2500.

3. The hydrophilic imide resin according to claim 1, characterized in that, In the combination of the structures shown in equation (2) and equation (3), the molar ratio of equation (2) and equation (3) is 1:4-4:

1.

4. The hydrophilic imide resin according to claim 1, characterized in that, The structure of the polyether segment is shown in formula (4). -(CH2CH2O) m (CH2CHCH3O) n R 4 (4) Where m≥0, n≥0, 1≤m+n≤50, R 4 Selected from H or C1-C18 alkyl groups.

5. The hydrophilic imide resin according to claim 4, characterized in that, Where m ≥ 1.2n, and R 4 Selected from C4-C18 alkyl groups.

6. The hydrophilic imide resin according to claim 4, characterized in that, Where m < 1.2n, where R 4 Selected from H or C1-C4 alkyl groups.

7. A method for preparing the hydrophilic imide resin according to any one of claims 1-6, characterized in that, Includes the following steps: The polyamine compound and the alkyl maleate ester undergo a Michael addition reaction to obtain the first acepartic resin; The first aspartic resin undergoes a first imide reaction with the double-terminated primary amine polyether to obtain the hydrophilic imide resin; Alternatively, the first aspartic resin reacts with the bi-terminated primary amine polyether to undergo a second imide reaction, and then the R is added. 3 The corresponding monoamine compound R 3 NH2 is used to carry out a third imide reaction to obtain the hydrophilic imide resin; R 3 The meaning of is as described above.

8. The method for preparing the hydrophilic imide resin according to claim 7, characterized in that, The catalysts for the first imide reaction, the second imide reaction, and the third imide reaction are individually selected from one or more combinations of C6-C18 fatty acids, benzotriazoles, and substituted benzotriazoles.

9. The method for preparing the hydrophilic imide resin according to claim 7, characterized in that, The molar ratio of the first aspartic resin to the dual-terminated primary amine polyether is 1.8-2.2:

1.

10. The method for preparing the hydrophilic imide resin according to claim 7, characterized in that, The molar ratio of the first aspartic resin to the monoamine compound is 1:0.2-1.

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