Imide secondary amino resin and preparation method thereof

Abstract

The invention provides imide secondary amino resin and a preparation method thereof, and relates to the technical field of amino resin. The structure of the imide secondary amino resin is # imgabs0 #, X is selected from a divalent organic structure which is left after two primary amino groups of a diamine compound are removed and is reactive with an isocyanate group at 100 DEG C and has the average molecular weight of 50-5000, R1 and R2 are independently selected from C5-C6 cycloalkyl, C6-C12 substituted cycloalkyl, C1-C20 alkyl or C2-C20 substituted alkyl, and the end groups of R1 and R2 are independently not-OH or-NH2. Compared with aspartic acid ester resin, the imide secondary amino resin disclosed by the invention has better heat resistance and hydrolysis resistance and higher mechanical strength.

Description

Technical Field

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

[0002] Aspartic acid ester resin is a kind of alicyclic secondary amino resin, which is prepared by Michael addition reaction of maleic acid ester (such as diethyl maleate) and alicyclic amine (such as 4,4'-diaminodicyclohexylmethane or 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane), and can be combined with isocyanate curing agent and reacted to obtain aspartic acid polyurea. The main chain structure of aspartic acid ester resin provides high weather resistance and excellent mechanical properties for aspartic acid polyurea, and the ester group of the side chain provides good internal plasticization and solvation for aspartic acid polyurea, ensuring the low viscosity and good flexibility of aspartic acid ester resin. However, due to the ester group of the side chain, the hardness, high temperature resistance and chemical resistance of aspartic acid polyurea are not outstanding, which limits the application of aspartic acid polyurea under harsh conditions. In addition, the stability of the ester group is poor, and it is not stable enough under water environment, high temperature and other conditions, resulting in obvious weight loss, loss of gloss and shrinkage of aspartic acid polyurea under water environment, high temperature and other conditions.

[0003] Therefore, it is necessary to modify the aspartic acid ester resin to improve its water resistance, high temperature resistance and other properties, thereby improving the hardness, high temperature resistance, chemical resistance, water resistance and the like of the aspartic acid polyurea. Summary of the invention

[0004] The imide structure has good stability, water resistance and high temperature resistance. The prior art reports the use of maleimide to replace maleate to prepare asparagine resin, but due to the limitation of the maleimide structure, the structure of alicyclic secondary amine resin is limited, and it is not easy to obtain alicyclic secondary amine resins with various structures. In order to solve the above technical problems, the present invention provides an imide secondary amine resin and a preparation method thereof.

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

[0006] An imide secondary amine resin having a structure as shown in the following formula (1):

[0007]

[0008] Wherein, X is selected from a divalent organic structure having an average molecular weight of 50-5000 which is inert to react with isocyanate groups at 100° C. and which remains after two primary amino groups are removed from a diamine compound; R1 and R2 are independently selected from C5-C6 cycloalkyl, C6-C12 substituted cycloalkyl, C1-C20 hydrocarbon or C2-C20 substituted hydrocarbon; and the end groups of R1 and R2 are independently not -OH or -NH2.

[0009] Preferably, R1 and R2 are independently selected from C5-C6 cycloalkyl, C6-C12 oxygen-substituted cycloalkyl, C6-C12 nitrogen-substituted cycloalkyl or C6-C12 sulfur-substituted cycloalkyl.

[0010] Preferably, R1 and R2 are independently selected from C2-C18 hydrocarbon groups or C3-C18 substituted hydrocarbon groups.

[0011] A method for preparing an imide secondary amine resin according to any of the above technical solutions, comprising adding an aspartic acid ester resin into a reaction vessel, adding a catalyst, heating to 80-150° C., adding a monofunctional primary amine compound, continuing the isothermal reaction and continuously removing the generated alcohol from the reaction system until the aspartic acid ester resin is completely reacted, thereby obtaining the imide secondary amine resin;

[0012] The general structural formula of the monofunctional primary amine compound is as shown in the following formula (2) or (3), or the monofunctional primary amine compound is a combination of the structures shown in formula (2) and (3),

[0013] R1NH2(2)

[0014] R2NH2(3)

[0015] Wherein, R1 and R2 have the same meanings as described above.

[0016] Preferably, the catalyst is selected from one or a combination of two or more of C8-C18 fatty acid, benzotriazole and substituted benzotriazole.

[0017] Preferably, the catalyst is selected from 1-hydroxybenzotriazole.

[0018] Preferably, the weight of the catalyst is 0.1-0.5% of the weight of the aspartic acid ester resin.

[0019] Preferably, the molar ratio of the aspartic acid ester resin to the monofunctional primary amine compound is 1:1.8-2.5.

[0020] More preferably, the molar ratio is 1:1.9-2.3.

[0021] Preferably, the aspartic acid ester resin is completely reacted until the ester groups in the reaction system disappear as determined by FT-IR.

[0022] The beneficial effects of the present invention are:

[0023] (1) The present invention can easily obtain an imide secondary amine resin by imidization reaction of a monofunctional primary amine compound with the ester group of an aspartic acid ester resin, and the conversion rate is high. The aspartic acid ester resin raw material can basically react completely and be converted into an imide secondary amine resin.

[0024] (2) The imide secondary amine resin of the present invention can directly adopt commercially available aspartic acid ester resin, and the raw materials are easy to obtain.

[0025] (3) The imide secondary amine resin of the present invention can be prepared by using different monofunctional primary amine compounds to obtain imide secondary amine resins with different terminal structures. The preparation method is more flexible and can obtain imide secondary amine resins with different structures and properties. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further illustrated and described below through specific implementation methods.

[0027] In order to provide an imide secondary amine based resin with a flexible structure, the present invention provides an imide secondary amine based resin having a structure as shown in the following formula (1):

[0028]

[0029] Wherein, X is selected from a divalent organic structure having an average molecular weight of 50-5000 which is inert to react with isocyanate groups at 100° C. and which remains after two primary amino groups are removed from a diamine compound; R1 and R2 are independently selected from C5-C6 cycloalkyl, C6-C12 substituted cycloalkyl, C1-C20 hydrocarbon or C2-C20 substituted hydrocarbon; and the end groups of R1 and R2 are independently not -OH or -NH2.

[0030] In the above structure (1) of the present invention, the imide structure replaces the ester group of the existing aspartic acid ester at both ends of the imide secondary amine resin structure. Compared with aspartic acid ester, the imide secondary amine resin has better hydrolysis resistance, high temperature resistance and other properties. Moreover, since the imide is a rigid structure, the mechanical strength of the polyurea obtained after the imide secondary amine resin is cured with a curing agent can also be improved.

[0031] In the structure of formula (1), if the terminal groups of R1 and R2 are hydroxyl groups or primary amino groups, the operation time after mixing with the curing agent will be shortened. Therefore, the terminal groups of R1 and R2 are not -OH or -NH2.

[0032] In the present invention, the above diamine compound is not particularly limited, and can be a diamine compound commonly used in the field of aspartic acid ester resin, such as 1,4-cyclohexanediamine, 1,3-cyclohexanediamine, 1,3-cyclopentanediamine, 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, polyetheramine, etc. Polyetheramine can be purchased directly from the market, such as polyetheramine D-230, polyetheramine D-400, polyetheramine D-2000, polyetheramine ED-600, polyetheramine ED-900, polyetheramine T-403, polyetheramine T-5000, etc., but are not limited to the above-mentioned ones.

[0033] In a preferred embodiment of the present invention, R1 and R2 are independently selected from C5-C6 cycloalkyl, C6-C12 oxygen-substituted cycloalkyl, C6-C12 nitrogen-substituted cycloalkyl or C6-C12 sulfur-substituted cycloalkyl. In the present invention, R1 and R2 may be the same or different. For example, R1 and R2 may be cyclohexyl, cycloalkyl, 2-methylcyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2-methylcyclopentyl, etc.

[0034] In a preferred embodiment of the present invention, R1 and R2 are independently selected from C2-C18 hydrocarbon groups or C3-C18 substituted hydrocarbon groups. For example, R1 and R2 can be butyl, isobutyl, 1-hexyl, isopropyl, isooctyl, lauryl, stearyl, 9-octadecene, -CH2CH2OCH3, -CH2CH2OCH2CH3, polyethylene glycol segment -(CH2CH2O) a CH3, polyether segment-(CH2CH2O) m (CH2CHCH3O) n CH3, a>0, m≥0, n≥0, m+n>0. When R1 and / or R2 are hydrophilic polyether segments, such as polyethylene glycol segments, etc., the imide secondary amine resin of the present invention can be endowed with good hydrophilicity or hydrophilic-lipophilic properties, and can be used as a hydrophilic resin, surfactant or emulsifier.

[0035] In order to be more flexible in the preparation method, on the other hand, the present invention provides a method for preparing the imide secondary amine resin described in any one of the above technical solutions, adding an aspartic acid ester resin into a reaction container, adding a catalyst, heating to 80-150° C., adding a monofunctional primary amine compound, continuing the constant temperature reaction and continuously removing the generated alcohol from the reaction system until the aspartic acid ester resin reacts completely, thereby obtaining the imide secondary amine resin of the present invention;

[0036] The general structural formula of the monofunctional primary amine compound is shown in the following formula (2) or (3), or the monofunctional primary amine compound is a combination of the structures shown in formula (2) and (3),

[0037] R1NH2(2)

[0038] R2NH2(3)

[0039] Wherein, R1 and R2 have the same meanings as described above.

[0040] In the preparation method of the imide secondary amine-based resin of the present invention, commercially available aspartic acid ester resin (such as F420, F520, F524 and other products of Feiyang Junyan Company) can be directly used, and directly reacted with a monofunctional primary amine compound under the action of a catalyst to obtain the imide secondary amine-based resin. By using the same monofunctional primary amine compound, imide secondary amine-based resins with the same end group structure can be obtained; by using different monofunctional primary amine compounds, imide secondary amine-based resins with different end group structures can be obtained. In specific operations, one monofunctional primary amine compound can be added first for reaction, and then another monofunctional primary amine compound can be added for reaction.

[0041] In the present invention, the combination of the structures represented by formula (2) and (3) has no particular limitation in terms of molar ratio or weight ratio, and can be selected based on the properties of the obtained imide secondary amine resin. For example, the molar ratio of the structures represented by formula (2) and (3) can be any value of 5:1, 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:4, 1:5, etc., without any particular limitation.

[0042] In a preferred embodiment of the present invention, the catalyst is selected from one or two or more combinations of C8-C18 fatty acids, benzotriazole and substituted benzotriazole. Using the above catalyst, the speed of the imide reaction can be accelerated. And by continuously removing the alcohol produced from the system (the removal method can be heated to more than the boiling point of the alcohol so that the alcohol is steamed or continuously introduced into the gas to take away the alcohol produced), the imide reaction is promoted to be complete. For example, the C8-C18 fatty acid can be lauric acid, stearic acid, etc., and the substituted benzotriazole can be 1-hydroxybenzotriazole, etc.

[0043] In a preferred embodiment of the present invention, the catalyst is selected from 1-hydroxybenzotriazole.

[0044] In a preferred embodiment of the present invention, the weight of the catalyst is 0.1-0.5% of the weight of the aspartic acid ester resin. For example, the weight of the catalyst is any value of 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, etc., based on the weight of the aspartic acid ester resin, without any particular limitation.

[0045] In a preferred embodiment of the present invention, the molar ratio of aspartic acid ester resin to the monofunctional primary amine compound is 1:1.8-2.5. The molar ratio of aspartic acid ester resin to the monofunctional primary amine compound in the above range can promote the conversion of most or all of the ester groups into imide. For example, the molar ratio of aspartic acid ester resin to the monofunctional primary amine compound can be any value of 1:1.8, 1:1.85, 1:1.9, 1:1.95, 1:2, 1:2.05, 1:2.1, 1:2.15, 1:2.2, 1:2.25, 1:2.3, 1:2.35, 1:2.4, 1:2.45, 1:2.5, etc., without special restrictions. More preferably, the molar ratio is 1:1.9-2.3. Or further preferably, the molar ratio is 1:2.0-2.2.

[0046] In a preferred embodiment of the present invention, the aspartic acid ester resin is completely reacted until the ester group disappears in the reaction system as measured by FT-IR. FT-IR can sensitively detect the ester group in the reaction system. When FT-IR detects that there is no ester group in the reaction system, it can be considered that the aspartic acid ester resin has been completely reacted.

[0047] The technical solution of the present invention is further described and illustrated according to various embodiments below.

[0048] Example 1

[0049] Place 1 mol of asparagus resin F420 (Feiyang Junyan Co., Ltd.) into a 1L four-necked flask, stir and add 0.6g of 1-hydroxybenzotriazole to fully dissolve, heat to 120°C, and slowly add 2 mol of oleylamine. Keep nitrogen flowing through the reaction system, and remove the ethanol produced by the reaction through the distillation head. Take samples and use FT-IR to detect the ester absorption peak (1730~1735cm -1 ), react until the ester absorption peak disappears in the reaction system, reduce the pressure to -0.099 MPa and remove low boiling points by vacuuming, and after cooling, obtain a brown-red transparent slightly turbid viscous liquid, which is the imide secondary amine resin.

[0050] In the imide secondary amine resin of this embodiment, in the structure of the above formula (1), both R1 and R2 are 9-octadecene.

[0051] Example 2

[0052] Place 1 mol of asparagine resin F420 into a 1L four-necked flask, stir and add 0.8 g of 1-hydroxybenzotriazole to fully dissolve, heat to 90°C, and slowly add 2.2 mol of 1-hexylamine. Keep nitrogen flowing through the reaction system and remove the ethanol produced by the reaction through the distillation head. Take samples and use FT-IR to detect the ester absorption peak (1730-1735 cm -1), react until the ester absorption peak disappears in the reaction system, reduce the pressure to -0.099 MPa and remove low boiling points by vacuuming, and after cooling, obtain a brown-red transparent slightly turbid viscous liquid, which is the imide secondary amine resin.

[0053] In the imide secondary amine resin of this embodiment, in the structure of the above formula (1), both R1 and R2 are 1-hexyl.

[0054] Example 3

[0055] Place 1 mol of asparagine resin F420 into a 1L four-necked flask, stir and add 0.8 g of 1-hydroxybenzotriazole to fully dissolve, heat to 120°C, and slowly add 1 mol of 1-hexylamine. Keep nitrogen flowing through the reaction system and remove the ethanol produced by the reaction through the distillation head. Take samples and use FT-IR to detect the ester absorption peak (1730-1735 cm -1 ) changes, react until the ester absorption peak in the reaction system does not change, and continue to add 1 mol of terminal amino polyethylene glycol NH2CH2CH2(OCH2CH2) 12.5 OCH3, react until the ester absorption peak disappears in the reaction system, reduce the pressure to -0.099MPa and remove low boiling points by vacuuming, and after cooling, obtain a brown-red transparent slightly turbid viscous liquid, which is the imide secondary amine resin.

[0056] The imide secondary amine resin of this embodiment, in the above formula (1), R1 is 1-hexyl, R2 is -CH2CH2(OCH2CH2) 12.5 OCH3.

[0057] The above-mentioned imide secondary amine resin was added to pure water to prepare 0.5wt% and 1wt% aqueous solutions, respectively. The aqueous solutions were nearly colorless and transparent, and the surface tensions measured by the platinum plate method were 25.2mN / m and 24.5mN / m, respectively. This shows that the imide secondary amine resin obtained in this example has good surface activity.

[0058] The above-mentioned imide secondary amine resin was added to pure water to prepare a 10wt% aqueous solution. The aqueous solution was opaque, and resin was present at the bottom after being placed for 2 days, indicating that the hydrophilicity of the imide secondary amine resin of this embodiment is not enough to make the imide secondary amine resin a hydrophilic resin.

[0059] Example 4

[0060] 1 mol of asparagine resin F420 was placed in a 1L four-necked flask, stirred and 1.0 g of 1-hydroxybenzotriazole was added to fully dissolve, the temperature was raised to 140°C, and 2 mol of the amine-terminated polyethylene glycol in Example 3 was slowly added. Nitrogen was kept flowing through the reaction system, and the ethanol produced by the reaction was taken out through the distillation head. The sample was taken and the ester absorption peak (1730-1735 cm-1 ), react until the ester absorption peak disappears in the reaction system, reduce the pressure to -0.099 MPa and remove low boiling points by vacuuming, and after cooling, obtain a brown-red transparent slightly turbid viscous liquid, which is the imide secondary amine resin.

[0061] In the imide secondary amine resin of this embodiment, in the structure of the above formula (1), R1 and R2 are both -CH2CH2(OCH2CH2) 12.5 OCH3.

[0062] The above imide secondary amine resin was added to pure water to prepare a 40wt% aqueous solution, which was translucent, indicating good solubility. After being placed for 2 months, the aqueous solution had no abnormal phenomenon such as precipitation or oil separation.

[0063] Example 5

[0064] Place 1 mol of asparagus resin F520 (Feiyang Junyan Co., Ltd.) into a 1L four-necked flask, stir and add 1.0 g of 1-hydroxybenzotriazole to fully dissolve, heat to 120°C, and slowly add 2.1 mol of 1-laurylamine. Keep nitrogen flowing through the reaction system, and remove the ethanol produced by the reaction through the distillation head. Take samples and use FT-IR to detect the ester absorption peak (1730-1735 cm -1 ), react until the ester absorption peak disappears in the reaction system, heat to 150°C and reduce the pressure to -0.099 MPa to remove low boiling points by vacuuming, and after cooling, obtain a brown-red transparent slightly turbid viscous liquid, which is the imide secondary amine resin.

[0065] In the imide secondary amine resin of this embodiment, in the structure of the above formula (1), both R1 and R2 are lauryl.

[0066] Example 6

[0067] Place 1 mol of asparagine resin F520 into a 1L four-necked flask, stir and add 1.0 g of 1-hydroxybenzotriazole to fully dissolve, heat to 120°C, and slowly add 1 mol of 1-laurylamine. Keep nitrogen flowing through the reaction system and remove the ethanol produced by the reaction through the distillation head. Take samples and use FT-IR to detect the ester absorption peak (1730-1735 cm -1 ) changes, react until the ester absorption peak in the reaction system does not change, and continue to add 1 mol of terminal amino polyether NH2CH2CH2(OCH2CH2) 20.3 (OCH2CHCH3) 6.8 OCH3, heat to 140℃, react until the ester absorption peak disappears in the reaction system, reduce the pressure to -0.099MPa to remove low boiling points, and after cooling, obtain a brown-red transparent slightly turbid viscous liquid, which is the imide secondary amine resin.

[0068] The imide secondary amine resin of this embodiment, in the above formula (1), R1 is 1-octyl, R2 is -CH2CH2(OCH2CH2) 20.3 (OCH2CHCH3) 6.8 OCH3.

[0069] The above-mentioned imide secondary amine resin was added to pure water to prepare 0.5wt% and 1wt% aqueous solutions, respectively. The aqueous solutions were nearly colorless and transparent, and the surface tensions measured by the platinum plate method were 24.8mN / m and 24.3mN / m, respectively. This shows that the imide secondary amine resin obtained in this example has good surface activity.

[0070] Performance Testing

[0071] The examples 1, 2, 5, F420 resin and F520 resin were mixed with isocyanate curing agent (isocyanate curing agent is composed of 3% HDI trimer, 10% HMDI and 87% IPDI and polyether polyol adduct curing agent) according to the total molar content of secondary amine and hydroxyl groups and NCO molar amount of 1:1.05, and the premix was made into a coating with a thickness of 0.5 mm, cured at 35±2°C for 15 days, and the tensile strength and heat deformation temperature were tested. The higher the heat deformation temperature, the better the heat resistance.

[0072] The above premix is ​​formed into a film on the clean tinplate surface with a thickness of 0.2 mm, and cured at 35±2°C for 15 days. The retention time after boiling in 100°C water is tested. The longer the time, the better the hydrolysis resistance.

[0073] The results are shown in Table 1 below.

[0074] Tensile strength / MPa Heat deformation temperature / ℃ 100℃ boiling time Example 1 17.2 155 6h Example 2 17.9 160 5.5h F420 resin 15.4 148 2h Example 5 16.3 160 7.5h F520 resin 14.8 154 3.5h

[0075] It can be seen from the data results in Table 1 that the imide secondary amine based resin of the present invention has higher tensile strength, heat deformation temperature and hydrolysis resistance after curing than the existing asparagus resin.

[0076] Combining the results of Example 3, Example 4 and Example 6, it is shown that the properties of the imide secondary amine resin of the present invention can be flexibly adjusted by adjusting the structures at both ends.

[0077] 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. An imide secondary amine resin, characterized in that: It has the structure shown in the following formula (1), Wherein, X is selected from a divalent organic structure having an average molecular weight of 50-5000 which is inert to react with isocyanate groups at 100° C. and which remains after two primary amino groups are removed from a diamine compound; R1 and R2 are independently selected from C5-C6 cycloalkyl, C6-C12 substituted cycloalkyl, C1-C20 hydrocarbon or C2-C20 substituted hydrocarbon; and the end groups of R1 and R2 are independently not -OH or -NH2.

2. The imide secondary amine resin according to claim 1, characterized in that: The R1 and R2 are independently selected from C5-C6 cycloalkyl, C6-C12 oxygen-substituted cycloalkyl, C6-C12 nitrogen-substituted cycloalkyl or C6-C12 sulfur-substituted cycloalkyl.

3. The imide secondary amine resin according to claim 1, characterized in that: The R1 and R2 are independently selected from C2-C18 hydrocarbon groups or C3-C18 substituted hydrocarbon groups.

4. A method for preparing the imide secondary amine resin according to any one of claims 1 to 3, characterized in that: Adding aspartic acid ester resin to a reaction container, adding a catalyst, raising the temperature to 80-150° C., adding a monofunctional primary amine compound, continuing the constant temperature reaction and continuously removing the generated alcohol from the reaction system until the aspartic acid ester resin is completely reacted, thereby obtaining the imide secondary amine resin; The general structural formula of the monofunctional primary amine compound is as shown in the following formula (2) or (3), or the monofunctional primary amine compound is a combination of the structures shown in formula (2) and (3), R1NH2(2) R2NH2(3) Wherein, R1 and R2 have the same meanings as described above.

5. The method for preparing the imide secondary amine resin according to claim 4, characterized in that: The catalyst is selected from one or a combination of two or more of C8-C18 fatty acid, benzotriazole and substituted benzotriazole.

6. The method for preparing the imide secondary amine resin according to claim 4, characterized in that: The catalyst is selected from 1-hydroxybenzotriazole.

7. The method for preparing the imide secondary amine resin according to claim 4, characterized in that: The weight of the catalyst is 0.1-0.5% of the weight of the aspartic acid ester resin.

8. The method for preparing the imide secondary amine resin according to claim 4, characterized in that: The molar ratio of the aspartic acid ester resin to the monofunctional primary amine compound is 1:1.8-2.

5.

9. The method for preparing the imide secondary amine resin according to claim 8, characterized in that: The molar ratio is 1:1.9-2.

3.

10. The method for preparing the imide secondary amine resin according to claim 4, characterized in that: The aspartic acid ester resin reaction is complete when the ester group disappears in the reaction system as measured by FT-IR.

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