Hydrophilic secondary amino resin and preparation method thereof

Abstract

The invention provides hydrophilic secondary amino resin and a preparation method thereof, and relates to the technical field of amino resin. The hydrophilic secondary amino resin has a PA-L-CH-L-PA structure,-CH-is a hydrophilic structure,-L-is an intermediate structure,-PA is an aspartic resin structure, and the hydrophilic secondary amino resin can be obtained by carrying out imide reaction on aspartic ester resin, then reacting with a diisocyanate compound and then reacting with aspartic ester resin. The hydrophilic secondary amino resin disclosed by the invention has the characteristics of adjustable hydrophilicity, good hydrolysis resistance and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of amino resins and relates to a hydrophilic secondary amino resin and a preparation method thereof. Background Art

[0002] Aspartic acid ester resin, also known as asparagine, is generally obtained by Michael addition reaction of dialkyl maleate and polyamine compounds. It is often used in the field of coatings when combined with isocyanate curing agent. It has the characteristics of high solid and low viscosity, good weather resistance, high adhesion, and good salt spray resistance. However, due to the presence of a large number of ester groups in aspartic acid ester resin, its hydrolysis resistance is poor, especially its acid and alkali resistance is poor. In addition, the ester group will also affect the heat resistance of the coating, resulting in insufficient heat resistance. Although it can be adjusted by adjusting the resin structure, such as introducing steric groups in the structure to improve the hydrolysis resistance of the ester group, it still cannot solve the hydrolysis problem of the ester group.

[0003] Therefore, it is necessary to adjust the structure of aspartic acid ester resin to solve its deficiencies in hydrolysis resistance and heat resistance.

[0004] In addition, with the increasing requirements for environmental protection, although aspartic acid ester resin has the characteristics of high solid and low viscosity, and high solid content (generally >95%), water-based materials are gradually becoming a trend, and the development of water-based aspartic acid ester resin is imperative. When aspartic acid ester resin is modified into a hydrophilic resin, prepared into an emulsion, or prepared into an aqueous dispersion, the poor hydrolysis resistance of the ester group will affect the stability and performance of the water-based aspartic acid ester resin, especially in the prior art, the hydrophilic polyether structure is grafted onto the aspartic acid ester resin through the ester group. If the ester group is hydrolyzed, the hydrophilic polyether structure will inevitably fall off, resulting in the deterioration or loss of hydrophilicity of the aspartic acid ester resin, affecting the stability of the product. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a hydrophilic secondary amine resin and a preparation method thereof.

[0006] The technical solution of the present invention is as follows:

[0007] A hydrophilic secondary amino resin having a structure as shown in the following formula (1):

[0008] PA-L-CH-L-PA(1)

[0009] Wherein, -CH- is a hydrophilic structure having a structure as shown in the following formula (2) or (3), or a combination of the structures shown in formula (2) and formula (3),

[0010]

[0011] wherein X is selected from a divalent organic structure having an average molecular weight of 50-500 which is inert to react with isocyanate groups at 100°C after removing two primary amino groups from a first divalent organic amine, R1 and R2 are independently selected from C1-C4 alkyl groups, R3 is selected from a monovalent polyether structure which is remaining after removing primary amino groups from a first single-ended amino polyether, and the solubility of the first single-ended amino polyether in pure water at 25°C is not less than 10g / 100g water,

[0012]

[0013] wherein Y is selected from a divalent organic structure having an average molecular weight of 50-500 which is inert to react with isocyanate groups at 100° C. after removing two primary amino groups from a second dibasic organic amine, R4 and R5 are independently selected from a monovalent polyether structure which is remaining after removing primary amino groups from a second single-ended amino polyether, and the solubility of the second single-ended amino polyether in pure water at 25° C. is not less than 10 g / 100 g water;

[0014] -L- is an intermediate structure having the structure shown in the following formula (4),

[0015]

[0016] Wherein, R6 is a divalent organic structure remaining after removing two isocyanate groups from a diisocyanate compound;

[0017] -PA is an asparagine resin structure having the structure shown in the following formula (5):

[0018]

[0019] wherein Z is selected from a divalent organic structure having an average molecular weight of 50-500 which is inert to the isocyanate group at 100° C. after removing two primary amino groups from the third divalent organic amine; and R7, R8, R9 and R 10 Independently selected from C1-C4 alkyl.

[0020] Preferably, the general structural formula of the first single-ended amino polyether and the second single-ended amino polyether is independently as shown in the following formula (6):

[0021] NH2CH2CH2(OCH2CH2) m (OCH2CHCH3) n OR 11 (6)

[0022] Among them, R 11 Selected from H or C1-C8 alkyl, m≥3, n≥0, mn≥3.

[0023] More preferably, the values ​​of m and n satisfy: m+n≤100.

[0024] Preferably, the diisocyanate compound is selected from one or a combination of two or more of pentamethylene diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexyl diisocyanate, 2-methyl-1,4-cyclohexyl diisocyanate, isophorone diisocyanate and 4,4'-dicyclohexylmethane diisocyanate.

[0025] A method for preparing the hydrophilic secondary amine resin according to any one of the above embodiments comprises the following steps:

[0026] Adding a catalyst to the first winter resin, raising the temperature to 90-130° C., adding the first single-terminated amino polyether or the second single-terminated amino polyether, and maintaining dealcoholization until no bubbles are generated to obtain a first prepolymer;

[0027] The first prepolymer is mixed with a diisocyanate compound and reacted to obtain a second prepolymer terminated with a diisocyanate;

[0028] The second prepolymer is added with the second aspart resin to react, thereby obtaining the hydrophilic secondary amino resin.

[0029] Preferably, the catalyst is selected from one or a combination of two or more of C4-C18 fatty acids, benzotriazole and substituted benzotriazole.

[0030] Preferably, the weight of the catalyst is 0.1%-0.5% of the weight of the first asparagus resin.

[0031] Preferably, the molar ratio of the first single-terminated amino polyether or the second single-terminated amino polyether to the first asparagine resin is 1-2:1.

[0032] Preferably, the molar ratio of the first prepolymer to the diisocyanate compound is 1:2-10.

[0033] Preferably, the molar ratio of the second prepolymer to the second aspart resin is 1:1.9-2.2.

[0034] The beneficial effects of the present invention are:

[0035] (1) In the hydrophilic secondary amine resin structure of the present invention, the imide structure is distributed on the side chain of the resin structure, which improves the performance of the resin (such as heat resistance and hydrolysis resistance) while having little effect on the rigidity of the resin structure. In addition, the polyether structure on the imide structure of the side chain can protect the resin, reducing or avoiding the exposure of the ester group in the resin to the outside.

[0036] (2) At least the terminal group of the secondary amine resin of the present invention also contains an ester group, or the side chain also contains an ester group, which can provide some effects of the ester group, such as solvation effect, internal plasticization effect, etc., to adjust the properties of the secondary amine resin.

[0037] (3) The secondary amine resin of the present invention can combine the performance and characteristics of conventional aspartic acid ester resin and imide secondary amine resin, and has relatively excellent comprehensive performance. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further illustrated and described below through specific implementation methods.

[0039] In order to improve the structural stability and hydrolysis stability of a hydrophilic aspartic acid ester resin, the present invention provides a hydrophilic secondary amine resin having a structure as shown in the following formula (1):

[0040] PA-L-CH-L-PA(1)

[0041] Wherein, -CH- is a hydrophilic structure having a structure as shown in the following formula (2) or (3), or a combination of the structures shown in formula (2) and formula (3),

[0042]

[0043] wherein X is selected from a divalent organic structure having an average molecular weight of 50-500 which is inert to react with isocyanate groups at 100°C and which is left after two primary amino groups are removed from a first divalent organic amine; R1 and R2 are independently selected from C1-C4 alkyl groups; R3 is selected from a monovalent polyether structure which is left after primary amino groups are removed from a first single-terminated amino polyether; and the solubility of the first single-terminated amino polyether in pure water at 25°C is not less than 10 g / 100 g water;

[0044]

[0045] wherein Y is selected from a divalent organic structure having an average molecular weight of 50-500 which is inert to react with isocyanate groups at 100° C. after removing two primary amino groups from the second dibasic organic amine, R4 and R5 are independently selected from a monovalent polyether structure which is remaining after removing primary amino groups from the second single-terminated amino polyether, and the solubility of the second single-terminated amino polyether in pure water at 25° C. is not less than 10 g / 100 g water;

[0046] -L- is an intermediate structure having the structure shown in the following formula (4),

[0047]

[0048] Wherein, R6 is a divalent organic structure remaining after removing two isocyanate groups from a diisocyanate compound;

[0049] -PA is an asparagine resin structure having the structure shown in the following formula (5):

[0050]

[0051] wherein Z is selected from a divalent organic structure having an average molecular weight of 50-500 which is inert to the isocyanate group at 100° C. after removing two primary amino groups from the third divalent organic amine; and R7, R8, R9 and R 10 Independently selected from C1-C4 alkyl.

[0052] The hydrophilic secondary amine resin shown in the above formula (1) of the present invention can introduce a hydrophilic polyether segment on the side chain of a conventional aspartic acid ester resin through an imide reaction on the intermediate hydrophilic structure -CH- to provide a hydrophilic function, and the imide performance is stable and not easy to decompose or hydrolyze. Therefore, the hydrophilic secondary amine resin of the present invention has high stability, and the hydrophilicity and other properties of the hydrophilic secondary amine resin, such as surface activity, can be adjusted by designing the hydrophilic polyether structure and adjusting the substitution amount of the imide. -L- is an intermediate structure that plays a role in connecting the two structures -CH- and -PA. -PA is a conventional aspartic acid ester resin structure, and the properties of the aspartic acid ester resin, such as high solid and low viscosity, high adhesion, etc., can be introduced into the end group of the hydrophilic secondary amine resin, further improving the performance of the hydrophilic secondary amine resin. Moreover, the hydrophilic secondary amine resin of the present invention can shield and protect the ester groups of the side chains and terminal groups in an aqueous environment due to the shielding effect of the polyether segment on the -CH- structure, thereby delaying the hydrolysis of the ester groups.

[0053] In the present invention, the first divalent organic amine, the second divalent organic amine and the third divalent organic amine are all divalent organic amines commonly used in the field of asparagus resin, especially divalent organic amines containing cycloalkyl groups, such as 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 1,2-cyclohexanediamine, 1,3-cyclohexanediamine, 1,4-cyclohexanediamine, 2-methyl-1,4-cyclohexanediamine, 1,3-cyclopentanediamine, etc.

[0054] In the present invention, the first single-ended amino polyether and the second single-ended amino polyether have good hydrophilicity, and the solubility in pure water at 25°C is not less than 10g / 100g water. For example, the solubility can be any value of 10g / 100g water, 20g / 100g water, 30g / 100g water, 50g / 100g water, 70g / 100g water, 80g / 100g water, etc., without special restrictions. In a preferred embodiment of the present invention, the general structural formula of the first single-ended amino polyether and the second single-ended amino polyether is shown in the following formula (6):

[0055] NH2CH2CH2(OCH2CH2) m (OCH2CHCH3) n OR 11 (6)

[0056] Among them, R 11 Selected from H or C1-C8 alkyl, m≥3, n≥0, mn≥3.

[0057] In the present invention, the first single-terminated amino polyether and the second single-terminated amino polyether can be directly obtained from the market, such as ZM-1100 of Zibo Zhengda Polyurethane Co., Ltd. and CAM-2070 of Yangzhou Chenhua New Materials Co., Ltd., or single-terminated amino polyethylene glycol, such as methoxy polyethylene glycol amine, with a number average molecular weight of 400, 600, 800, 1000, etc. By using the single-terminated amino polyether, the terminal amino group can react with the ester group to form an imide structure and introduce the polyether structure into the hydrophilic secondary amino resin of the present invention. In the present invention, R 4 and R 5 It can be the same or different.

[0058] m and n represent the average degree of polymerization of -OCH2CH2- and -OCH2CHCH3-, respectively. If the values ​​of m and n are too high, or the value of m+n is too high, the reactivity of the terminal amino group will be reduced, which may affect the reaction efficiency and reaction degree of the imide reaction. In a more preferred embodiment of the present invention, the values ​​of m and n satisfy: m+n≤100.

[0059] The diisocyanate compound is an aliphatic diisocyanate, which has better weather resistance and other properties. In a preferred embodiment of the present invention, the diisocyanate compound is selected from one or a combination of two or more of pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HMDI), 1,4-cyclohexyl diisocyanate, 2-methyl-1,4-cyclohexyl diisocyanate, isophorone diisocyanate (IPDI) and 4,4'-dicyclohexylmethane diisocyanate (H12MDI).

[0060] On the other hand, the present invention also provides a method for preparing the hydrophilic secondary amine resin according to any one of the above embodiments, comprising the following steps:

[0061] Adding a catalyst to the first winter resin, raising the temperature to 90-130° C., adding the first single-terminal amino polyether or the second single-terminal amino polyether, and maintaining dealcoholization until no bubbles are generated to obtain a first prepolymer;

[0062] The first prepolymer is mixed with a diisocyanate compound and reacted to obtain a second prepolymer terminated with a diisocyanate;

[0063] The second prepolymer is added with the second aspart resin to react to obtain a hydrophilic secondary amine resin.

[0064] The hydrophilic secondary amine resin of the present invention can be obtained through the above three steps, with high reaction efficiency and short steps, and can be continuously carried out in the same reaction kettle.

[0065] In the present invention, the first asparagine resin and the second asparagine resin are both conventional asparagine resins, which can be obtained by Michael addition reaction of diethyl maleate and a diamine compound (4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, etc.), or can be directly purchased on the market, such as F420 resin, F520 resin, F220 resin, F421 resin, etc. of Feiyang Junyan Company, Desmophen NH 1420, NH 1520, etc. of Covestro Company.

[0066] In a preferred embodiment of the present invention, the catalyst is selected from one or a combination of two or more of C4-C18 fatty acids, benzotriazole and substituted benzotriazole. The use of a catalyst can accelerate the imide reaction rate and promote the reaction to completion. For example, the catalyst can be lauric acid, stearic acid, 1-hydroxybenzotriazole, etc.

[0067] In a preferred embodiment of the present invention, the weight of the catalyst is 0.1%-0.5% of the weight of the first-day asparagine resin. For example, the weight of the catalyst can be any value of 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, etc., of the weight of the first-day asparagine resin, without particular limitation.

[0068] In a preferred embodiment of the present invention, the molar ratio of the first single-ended amino polyether or the second single-ended amino polyether to the first asparagine resin is 1-2:1. By adjusting the molar ratio of the first single-ended amino polyether or the second single-ended amino polyether to the first asparagine resin, the amount of imide substitution on the first asparagine resin can be adjusted. When the molar ratio is 1:1, the structure shown in formula (2) is obtained; when the molar ratio is 1:2, the structure shown in formula (3) is obtained. When the molar ratio is between 1:1 and 1:2, a combination of the structure shown in formula (2) and the structure shown in formula (3) is obtained.

[0069] In a preferred embodiment of the present invention, the molar ratio of the first prepolymer to the diisocyanate compound is 1:2-10. Using the above technical solution, the two -NH- groups in the first polymer are converted into NCO groups. If the diisocyanate compound is excessive, the excess diisocyanate compound can be removed by methods such as vacuum distillation. For example, the molar ratio of the first prepolymer to the diisocyanate compound can be any value of 1:2, 1:2.2, 1:2.5, 1:3, 1:3.2, 1:3.5, 1:4, 1:4.5, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, etc., without special restrictions. More preferably, from the perspective of raw material utilization, the molar ratio of the first prepolymer to the diisocyanate compound can be 1:2-3.

[0070] In a preferred embodiment of the present invention, the molar ratio of the second prepolymer to the second asparagine resin is 1:1.9-2.2. By adopting the above technical solution, the asparagine resin structure can be grafted on both ends of the second prepolymer. For example, the molar ratio of the second prepolymer to the second asparagine resin can be any value in 1:1.9, 1:1.92, 1:1.94, 1:1.95, 1:1.97, 1:1.98, 1:1.99, 1:2, 1:2.02, 1:2.03, 1:2.05, 1:2.07, 1:2.08, 1:2.1, 1:2.12, 1:2.15, 1:2.17, 1:2.2, etc., without special restrictions. More preferably, the molar ratio of the second prepolymer to the second asparagine resin is 1:1.95-2.05.

[0071] The technical solution of the present invention is further described and illustrated according to various embodiments below. Unless otherwise specified, the parts described in the following embodiments are parts by weight.

[0072] Example 1

[0073] 1 mol of F420 resin and 0.25% of 1-hydroxybenzotriazole by weight of the F420 resin are added to a reaction container, the temperature is raised to 120° C., 1 mol of amino-terminated polyether ZM-1100 is added until reflux occurs in the reaction system, nitrogen is introduced to remove the generated ethanol until no bubbles are generated in the reaction system, and a first prepolymer is obtained; 2.02 mol of isophorone diisocyanate IPDI is continuously added to the above reaction container, stirred at room temperature for 3 hours, reduced pressure to below -0.099 MPa, heated to 170° C. to remove low-boiling substances, and a second prepolymer is obtained; 2 mol of F420 resin is continuously added to the above reaction container, stirred for reaction at room temperature for 2 hours, heated to 60° C. and stirred for reaction for 1 hour, and a hydrophilic secondary amino resin is obtained.

[0074] Example 2

[0075] The difference between this embodiment and embodiment 1 is that in embodiment 1, the amino-terminated polyether ZM-1100 is adjusted from 1 mol to 1.5 mol. The other steps remain unchanged.

[0076] Example 3

[0077] The difference between this embodiment and embodiment 1 is that in embodiment 1, the amino-terminated polyether ZM-1100 is adjusted from 1 mol to 2 mol. The other steps remain unchanged.

[0078] Example 4

[0079] The difference between this embodiment and embodiment 2 is that in embodiment 2, 2 mol of F420 resin is added and replaced with 2 mol of F520 resin. The other steps remain unchanged.

[0080] Example 5

[0081] 1 mol of F420 resin and 0.3% of 1-hydroxybenzotriazole by weight of the F420 resin were added to a reaction container, the temperature was raised to 110° C., 1.4 mol of methoxy-terminated amino-terminated polyethylene glycol (number average molecular weight 600) was added until reflux occurred in the reaction system, nitrogen was introduced to remove the generated ethanol until no bubbles were generated in the reaction system, and a first prepolymer was obtained; 2.8 mol of hexamethylene diisocyanate HMDI was continuously added to the above reaction container, stirred at room temperature for 3 hours, reduced pressure to below -0.099 MPa, and heated to 140° C. to remove low-boiling substances, and a second prepolymer was obtained; 1.95 mol of F420 resin was continuously added to the above reaction container, stirred and reacted at room temperature for 2 hours, and heated to 60° C. and continued to stir and react for 1 hour, to obtain a hydrophilic secondary amino resin.

[0082] Example 6

[0083] The difference between this example and Example 5 is that in Example 5, 1.95 mol of F420 resin was added and replaced with 2.03 mol of F420 resin. The other steps remain unchanged.

[0084] Example 7

[0085] 1 mol of F520 resin and 0.3% of 1-hydroxybenzotriazole by weight of the F520 resin were added to a reaction container, the temperature was raised to 130° C., 1 mol of methoxy-terminated amino-terminated polyethylene glycol (number average molecular weight 800) was added until reflux occurred in the reaction system, nitrogen was introduced to remove the generated ethanol until no bubbles were generated in the reaction system, and a first prepolymer was obtained; 2.2 mol of hexamethylene diisocyanate HMDI was continuously added to the above reaction container, stirred at room temperature for 3 hours, reduced pressure to below -0.099 MPa, and heated to 140° C. to remove low-boiling substances, and a second prepolymer was obtained; 2 mol of F420 resin was continuously added to the above reaction container, stirred and reacted at room temperature for 2 hours, and heated to 60° C. and continued to stir and react for 1 hour, to obtain a hydrophilic secondary amino resin.

[0086] Example 8

[0087] The difference between this example and Example 7 is that in Example 7, 1 mol of F520 resin initially added is replaced with 1 mol of F420 resin. The remaining steps remain unchanged.

[0088] Example 9

[0089] 1 mol of F420 resin and 0.3% of 1-hydroxybenzotriazole by weight of F420 resin were added to a reaction container, the temperature was raised to 110° C., 1 mol of methoxy-terminated amino-terminated polyethylene glycol (number average molecular weight 600) was added, reflux was generated in the reaction system, nitrogen was introduced to remove the generated ethanol until no bubbles were generated in the reaction system, 0.5 mol of amino-terminated polyether ZM-1100 was added, reflux was generated in the reaction system again, nitrogen was introduced again to remove the generated ethanol until no bubbles were generated in the reaction system again, and a first prepolymer was obtained; 2.8 mol of hexamethylene diisocyanate HMDI was added to the above reaction container, stirred at room temperature for 3 hours, reduced pressure to below -0.099 MPa, heated to 140° C. to remove low boiling points, and a second prepolymer was obtained; 2 mol of F420 resin was added to the above reaction container, stirred and reacted at room temperature for 2 hours, heated to 60° C. and continued to stir and react for 1 hour to obtain a hydrophilic secondary amino resin.

[0090] Example 10

[0091] The difference between this embodiment and embodiment 9 is that in embodiment 9, the amino-terminated polyether ZM-1100 is adjusted from 0.5 mol to 1 mol. The other steps remain unchanged.

[0092] Comparative Example 1

[0093] The hydrophilic polyaspartic acid ester resin was prepared according to the method of Example 1 in the prior art CN111303368A.

[0094] Performance Testing

[0095] Test method for water solubility of the resin to be tested: Under 25°C, weigh 100 grams of the resin sample to be tested and place it in a colorless and transparent container. Slowly add an appropriate amount of pure water while stirring, stir evenly, and then measure according to the method specified in GB 1721-2008 "Test Method for Appearance and Transparency of Varnish, Clear Oil and Thinner". Record the weight of pure water added when the instrument measurement value reaches 82. The results are shown in Table 1 below. The less the weight of pure water, the worse the hydrophilicity of the resin to be tested.

[0096] Alkali resistance test method of the resin to be tested: add the resin to be tested into a 5wt% NaOH aqueous solution to prepare a 10% solution, let it stand at room temperature (25°C), and observe the time when abnormal conditions such as turbidity, precipitation or oily floating matter appear in the solution, which is the hydrolysis time. Observe once every 2 hours. The occurrence of the above abnormal conditions indicates that the resin to be tested has been fully hydrolyzed and its hydrophilicity has weakened. The longer the hydrolysis time, the better the hydrolysis resistance.

[0097] The results are shown in Table 1 below.

[0098] Table 1

[0099] Resin to be tested Pure water weight / g Hydrolysis time / h Resin to be tested Pure water weight / g Hydrolysis time / h Example 1 148 24 Example 7 141 26 Example 2 173 30 Example 8 150 24 Example 3 190 38 Example 9 166 30 Example 4 165 44 Example 10 182 40 Example 5 187 28 Comparative Example 1 200 2 Example 6 182

[0100] It can be seen from the data results in Table 1 that the hydrophilicity of the hydrophilic secondary amino resin of the present invention can be flexibly adjusted and has good hydrolysis resistance under alkaline conditions.

[0101] As described above, the basic principles, main features and advantages of the present invention are shown and described. Those skilled in the art should understand that the present invention is not limited by the above embodiments, which are only preferred embodiments of the present invention and cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the scope of the present invention and the content of the specification should still be within the scope of the present invention. The scope of protection required by the present invention is defined by the attached claims and their equivalents.

Claims

1. A hydrophilic secondary amine resin, characterized in that: It has the structure shown in the following formula (1), PA-L-CH-L-PA(1) Wherein, -CH- is a hydrophilic structure having a structure as shown in the following formula (2) or (3), or a combination of the structures shown in formula (2) and formula (3), wherein X is selected from a divalent organic structure having an average molecular weight of 50-500 which is inert to react with isocyanate groups at 100°C after removing two primary amino groups from a first divalent organic amine, R1 and R2 are independently selected from C1-C4 alkyl groups, R3 is selected from a monovalent polyether structure which is remaining after removing primary amino groups from a first single-ended amino polyether, and the solubility of the first single-ended amino polyether in pure water at 25°C is not less than 10g / 100g water, wherein Y is selected from a divalent organic structure having an average molecular weight of 50-500 which is inert to react with isocyanate groups at 100° C. after removing two primary amino groups from a second dibasic organic amine, R4 and R5 are independently selected from a monovalent polyether structure which is remaining after removing primary amino groups from a second single-ended amino polyether, and the solubility of the second single-ended amino polyether in pure water at 25° C. is not less than 10 g / 100 g water; -L- is an intermediate structure having the structure shown in the following formula (4), Wherein, R6 is a divalent organic structure remaining after removing two isocyanate groups from a diisocyanate compound; -PA is an asparagine resin structure having the structure shown in the following formula (5): wherein Z is selected from a divalent organic structure having an average molecular weight of 50-500 which is inert to the isocyanate group at 100° C. after removing two primary amino groups from the third divalent organic amine; and R7, R8, R9 and R 10 Independently selected from C1-C4 alkyl.

2. The hydrophilic secondary amine resin according to claim 1, characterized in that The general structural formula of the first single-end amino polyether and the second single-end amino polyether are shown in the following formula (6): NH2CH2CH2(OCH2CH2) m (OCH2CHCH3) n OR 11 (6) Among them, R 11 Selected from H or C1-C8 alkyl, m≥3, n≥0, mn≥3.

3. The hydrophilic secondary amine resin according to claim 2, characterized in that: The values ​​of m and n satisfy: m+n≤100.

4. The hydrophilic secondary amine resin according to claim 1, characterized in that: The diisocyanate compound is selected from one or a combination of two or more of pentamethylene diisocyanate, hexamethylene diisocyanate, 1,4-cyclohexyl diisocyanate, 2-methyl-1,4-cyclohexyl diisocyanate, isophorone diisocyanate and 4,4'-dicyclohexylmethane diisocyanate.

5. A method for preparing a hydrophilic secondary amine resin according to any one of claims 1 to 4, characterized in that: The following steps are included: Adding a catalyst to the first winter resin, raising the temperature to 90-130° C., adding the first single-terminated amino polyether or the second single-terminated amino polyether, and maintaining dealcoholization until no bubbles are generated to obtain a first prepolymer; The first prepolymer is mixed with a diisocyanate compound and reacted to obtain a second prepolymer terminated with a diisocyanate; The second prepolymer is added with the second aspart resin to react, thereby obtaining the hydrophilic secondary amino resin.

6. The method for preparing a hydrophilic secondary amine resin according to claim 5, characterized in that: The catalyst is selected from one or a combination of two or more of C4-C18 fatty acid, benzotriazole and substituted benzotriazole.

7. The method for preparing a hydrophilic secondary amine resin according to claim 5, characterized in that: The weight of the catalyst is 0.1%-0.5% of the weight of the first asparagus resin.

8. The method for preparing a hydrophilic secondary amine resin according to claim 5, characterized in that: The molar ratio of the first single-terminated amino polyether or the second single-terminated amino polyether to the first asparagine resin is 1-2:

1.

9. The method for preparing a hydrophilic secondary amine resin according to claim 5, characterized in that: The molar ratio of the first prepolymer to the diisocyanate compound is 1:2-10.

10. The method for preparing a hydrophilic secondary amine resin according to claim 5, characterized in that: The molar ratio of the second prepolymer to the second aspart resin is 1:1.9-2.2.

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