Liquefied poly-sec-amine, its preparation and use

Abstract

The application provides a liquefied poly-sec-amines, a preparation method and application thereof. 4-[(4-aminocyclohexane)methyl]aniline is easy to crystallize into a solid at room temperature, which is very inconvenient for customers to use. The application makes the 4-[(4-aminocyclohexane)methyl]aniline liquefied through chemical modification, greatly improves the convenience of use, and reduces the energy consumption cost of heating and melting before use. When the liquefied poly-sec-amines are used as an epoxy resin curing agent, the curing activity is greatly improved compared with the raw material amine, and the poly-sec-amines have excellent flexibility. The epoxy resin composition containing the poly-sec-amines can not only realize rapid curing, but also has high surface gloss, good flexibility, high impact resistance of the cured paint film, excellent mechanical properties, and is suitable for the fields of coatings and composite materials, and is a new product with great market competitiveness.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, specifically relating to a liquefied polyamine, its preparation method, and its application. Background Technology

[0002] With the rapid development of the national economy, especially the construction industry, home decoration industry, automobile industry, shipbuilding industry and bridge industry, the application fields of coatings are becoming more and more extensive. At the same time, new requirements are being put forward for their performance.

[0003] In the process of coating application, in order to improve construction efficiency and reduce sagging, the curing speed of the coating is required to be fast. In the field of automotive paint, attention is paid to the aesthetic and decorative properties of the paint film, requiring the cured paint film to have high gloss, low brittleness, and good flexibility to reduce the cracking of the surface paint in the event of minor impacts. In the field of base coats for flooring, anti-corrosion coatings for tanks or pipelines, good chemical resistance of the coating is also required.

[0004] Epoxy resins, rich in polar hydroxyl groups, exhibit strong interaction with substrate surface groups and good adhesion, making them widely used in the coatings industry. However, traditional epoxy coatings suffer from some performance defects. A typical characteristic of epoxy resins is their high crosslinking density and high cohesive energy after curing, leading to brittleness and extremely poor flexibility in the epoxy coating. CN109423168A discloses a heat-resistant epoxy coating with excellent adhesion, high-temperature resistance, chemical resistance, and corrosion resistance. However, it lacks toughening modification and belongs to a traditional epoxy resin system, resulting in a brittle film with limited practical application value.

[0005] CN105400364A discloses a composite epoxy resin coating with high adhesion and good film flexibility, but it uses a traditional mixed aromatic and alicyclic amine curing agent, which has very low activity at room temperature and slow curing speed. In low-temperature and humid environments such as winter or underwater, the activity is too low to be used.

[0006] CN113861386A discloses an epoxy coating using polyoxypropylene triamine as a curing agent. The coating has properties such as heat resistance, water resistance, salt resistance, and corrosion resistance, and also has high impact resistance and mechanical properties. However, this aliphatic curing agent is prone to moisture absorption, which causes the coating surface to easily turn white, seriously affecting the aesthetics. It is only suitable for applications such as the seabed where the appearance of the coating is not important, and is not applicable to most daily applications (such as car paint, furniture paint, etc.).

[0007] To address the aforementioned issues, the industry urgently needs to develop a new type of epoxy resin coating with good film flexibility, high curing activity, and high surface gloss.

[0008] In addition, epoxy-based composite materials are widely used in wind turbine blades, automotive parts, furniture and windows, and other fields. Some fields have high requirements for the mechanical properties of materials after curing and molding. For example, the wind power field requires high impact strength. Therefore, epoxy-based composite materials that can meet this performance requirement have broad market prospects. Summary of the Invention

[0009] The purpose of this invention is to provide a liquefied polyamine, which uses crystalline solid amine as a raw material, greatly improving the convenience of use for customers after liquefaction. Simultaneously, the polyamine molecule also possesses excellent flexibility. When used as an epoxy resin curing agent, its curing activity is significantly enhanced compared to the raw material amine. Applying epoxy resin compositions containing this polyamine to coatings and composite materials not only achieves rapid curing but also produces cured paint films with high surface gloss, good flexibility, high impact strength, and excellent mechanical properties, sufficient to meet industry requirements.

[0010] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0011] A liquefied polyamine, said polyamine having one or more of the following structures:

[0012]

[0013] The liquefied polyamine provided by this invention has a novel molecular structure. Due to the presence of long aliphatic chain segments, it exhibits good molecular flexibility and excellent hydrophobic properties. These superior hydrophobic properties prevent the paint film from absorbing moisture and turning white when applied in the coatings field, resulting in high gloss. Furthermore, the introduction of hydroxyl groups into the new polyamine molecule gives it a self-catalytic effect when used as an epoxy resin curing agent, leading to high curing activity and a high degree of curing. This increased degree of curing results in excellent mechanical properties of the cured product.

[0014] This poly-secondary amine uses 4-[(4-aminocyclohexane)methyl]aniline as a raw material. 4-[(4-aminocyclohexane)methyl]aniline crystallizes into an oily solid at room temperature, requiring a high temperature of above 80°C for use as an epoxy curing agent. This invention modifies 4-[(4-aminocyclohexane)methyl]aniline into a liquid poly-secondary amine with a viscosity below 500 mPa·s, allowing direct mixing with epoxy resin without heating, significantly reducing energy costs. It provides downstream customers with efficient and convenient construction processes, making it a competitive product with market potential.

[0015] Another object of the present invention is to provide a method for preparing the liquefied polyamine.

[0016] A method for preparing the above-mentioned liquefied polyamine, wherein 4-[(4-aminocyclohexane)methyl]aniline undergoes a condensation reaction with M-[(Z)-8-pentadecanenyl]phenol and aldehyde to obtain the liquefied polyamine.

[0017] In one embodiment, the above preparation method involves the following reaction:

[0018]

[0019] In this invention, the molar ratio of 4-[(4-aminocyclohexane)methyl]aniline to M-[(Z)-8-pentadecanenyl]phenol and aldehyde in the method is 1:(1-2.5):(1-2.5).

[0020] In this invention, the aldehyde in the method is formaldehyde, preferably an aqueous formaldehyde solution and / or paraformaldehyde.

[0021] In this invention, the condensation reaction temperature in the method is 90-160℃, and the reaction time is 2-5h.

[0022] Another object of the present invention is to provide an epoxy resin composition that uses the above-mentioned liquefied polyamine as a curing agent, which not only enables rapid curing, but also produces a cured product with high surface gloss, good flexibility, and excellent mechanical properties.

[0023] An epoxy resin composition comprising the above-mentioned liquefied polyamine, or comprising liquefied polyamine prepared by the above method, wherein the composition comprises component A and component B in a mass ratio of (1-2):1;

[0024] Wherein, taking the total mass of component A as 100%, component A comprises the following raw materials:

[0025] Epoxy resin 45-58wt%

[0026] 31-45 wt% of filler

[0027] Diluent 8-11 wt%;

[0028] Based on a total mass of 100% for component B, component B comprises the following raw materials:

[0029]

[0030] In this invention, the epoxy resin in component A is selected from one or more of glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, and alicyclic epoxy resins.

[0031] In this invention, the filler in component A is selected from one or more of calcium carbonate, silicon dioxide, aluminum powder, talc powder, mica powder, and kaolin.

[0032] In this invention, the diluent in component A is selected from one or more of benzyl alcohol, xylene, n-butyl glycidyl ether, allyl glycidyl ether, and butanediol diglycidyl ether.

[0033] In this invention, the polyetheramine in component B is selected from... One or more of the T-403.

[0034] In this invention, the diluent in component B is selected from one or more of benzyl alcohol, xylene, n-butyl glycidyl ether, allyl glycidyl ether, and butanediol diglycidyl ether.

[0035] In this invention, the accelerator in component B is selected from nonylphenol, 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, etc. One or more of them.

[0036] Another object of the present invention is to provide a use of an epoxy resin composition.

[0037] Use of an epoxy resin composition, wherein the composition comprises the above-mentioned liquefied polyamine, or the composition comprises liquefied polyamine prepared by the above-mentioned method, or the composition is the above-mentioned epoxy resin composition, and the composition is used as an epoxy primer for automotive surfaces, a mid-coat for concrete floors, an anti-corrosion coating for tanks and pipelines, and an epoxy resin-based composite material.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] (1) 4-[(4-aminocyclohexane)methyl]aniline crystallizes into an oily solid at room temperature, requiring high-temperature melting above 80°C for use as an epoxy curing agent. This invention modifies 4-[(4-aminocyclohexane)methyl]aniline into a liquid polyamine with a viscosity below 500 mPa·s, allowing direct mixing with epoxy resin without heating, significantly reducing energy costs. This makes the construction process highly efficient and convenient for downstream customers, making it a highly competitive product with significant market potential.

[0040] (2) The liquefied polyamine has a novel molecular structure containing long aliphatic segments, good molecular flexibility, and excellent hydrophobic properties. At the same time, hydroxyl groups are introduced into the molecule. When used as an amine curing agent for epoxy resin, it has a self-catalytic effect, which significantly improves the curing activity and curing degree.

[0041] (3) The epoxy resin composition can not only achieve rapid curing, but also the cured paint film has high gloss and good toughness. The cured sample has excellent mechanical properties and is suitable for coatings and composite materials, which is in line with the industry development trend. Detailed Implementation

[0042] The present invention will be further illustrated by specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0043] The main raw materials and their sources are shown in Table 1:

[0044] Table 1. Main Raw Materials and Their Sources

[0045]

[0046]

[0047] The performance evaluation method is as follows:

[0048] Gel time: Refer to GB / T 12007.7-1989 "Determination of gel time of epoxy resin";

[0049] Light transmittance: Refer to ASTM D1746-2015 Standard Test Method for Transparency of Plastic Sheets, TH-09, Color Spectrum Technology (Zhejiang) Co., Ltd.;

[0050] Film toughness: Refer to GB / T 1732-1993 Test Method for Impact Resistance of Coating Film, BGD 304, Biaogeda Precision Instruments (Guangzhou) Co., Ltd.;

[0051] Impact strength: Refer to GB / T 1043.1-2008 Determination of impact properties of simply supported plastic beams Part 1: Non-instrumental impact test, ASR-5607, Guangdong ASR Instrument Technology Co., Ltd.;

[0052] Carbon nuclear magnetic resonance spectroscopy (NMR) 13 C NMR: The products were characterized using a nuclear magnetic resonance spectrometer, which was a Brucker Avance from Brucker (Beijing) Technology Co., Ltd.

[0053] Example 1

[0054] Liquefied polyamine 1# was prepared according to the following method:

[0055] Under nitrogen protection, 4-[(4-aminocyclohexane)methyl]aniline, M-[(Z)-8-pentadecanenyl]phenol, and paraformaldehyde were reacted in a molar ratio of 1:1:1. Trifluoroacetic anhydride was added as a protecting agent for the alicyclic amine group (the molar ratio of the protecting agent to 4-[(4-aminocyclohexane)methyl]aniline was 1.5:1). The condensation reaction was carried out at 125℃ for 3.5 h. Afterwards, the protecting agent was removed using the alcohol-base method (i.e., a solution containing K₂CO₃ was prepared). A water-alcohol solution (water to alcohol mass ratio 9:1) was prepared, with K2CO3 added at 2% of the total mass of the water-alcohol solution. This water-alcohol solution was added to the reaction solution at a mass ratio of 10%, and the mixture was refluxed for 4 hours to obtain the crude liquefied polyamine product after the protective reagent was removed. The crude product was then extracted with dichloromethane, retaining the organic phase. The organic phase was dried with anhydrous Na2SO4 and filtered. The water was removed by vacuum evaporation (90℃, absolute pressure 2 kPa) to obtain the target product, liquefied polyamine 1#, with a viscosity of 342 mPa·s. The results of the carbon NMR characterization are as follows:

[0056]

[0057] 13 C NMR (CDCl3, 600MHz, TMS): δ14.02(1C), 22.1(1C), 27.15(2C), 29.28(1C), 29.4(1C), 29.43( 2C), 29.69(1C), 29.9(1C), 30(1C), 30.2(2C), 31.37(1C), 33.85(1C), 34.72(1C), 35.56(1C) , 37.61(1C), 42.82(1C), 43.75(1C), 50.65(1C), 113.2(1C), 117.9(2C), 122.83(1C), 127.87 (1C), 128.25(1C), 129.9(2C), 130.6(2C), 133.96(1C), 135.1(1C), 148.43(1C), 159.98(1C)

[0058] Example 2

[0059] Liquefied polyamine 2# was prepared according to the following method:

[0060] Under nitrogen protection, a condensation reaction was carried out at 90℃ for 5 h with 4-[(4-aminocyclohexane)methyl]aniline, M-[(Z)-8-pentadecanenyl]phenol, and formaldehyde aqueous solution in a molar ratio of 1:1:1. Afterwards, the water was removed by vacuum evaporation (90℃, absolute pressure 2 kPa) to obtain the target product, liquefied polyamine 2#, with a viscosity of 350 mPa·s. The results of the carbon NMR characterization are as follows:

[0061]

[0062] 13 C NMR (CDCl3, 600MHz, TMS): δ14.12(1C), 22.2(1C), 28.27(2C), 29.33(1C), 29.38(1C), 29.4(1C), 29.7 9(1C), 31.27(1C), 31.75(1C), 33.45(2C), 33.75(1C), 34.62(1C), 35.46(1C), 37.51(1C), 41.61(1C), 46.38(1C), 56.54(1C), 112.11(1C), 114.35(2C), 124.32(1C), 127.5(1C), 127.72(1C), 128.15(1C), 1 28.39(1C), 128.75(1C), 128.76(2C), 132.7(1C), 134.05(1C), 136.58(1C), 147.33(1C), 157.65(1C).

[0063] Example 3

[0064] Liquefied polyamine 3# was prepared according to the following method:

[0065] Under nitrogen protection, a condensation reaction was carried out at 160℃ for 2 hours with 4-[(4-aminocyclohexane)methyl]aniline, M-[(Z)-8-pentadecanenyl]phenol, and paraformaldehyde in a molar ratio of 1:2.5:2.5. Afterwards, the water was removed by vacuum evaporation (90℃, absolute pressure 2 kPa) to obtain the target product, liquefied polyamine 3#, with a viscosity of 354 mPa·s. The results of the carbon NMR characterization are as follows:

[0066]

[0067] 13C NMR (CDCl3, 600MHz, TMS): δ14(2C), 22.2(2C), 26.9(2C), 29.3(4C), 29.4(4C), 29.7(2C), 30(2C), 31.1(2C) , 31.8(2C), 32.2(1C), 32.5(2C), 33.7(2C), 33.8(2C), 35.6(2C), 41.7(1C), 46.7(1C), 48.2(1C), 54.1(1C) , 114.9(1C), 115.2(2C), 115.3(1C), 121.3(1C), 121.5(1C), 122.2(1C), 125.1(1C), 127.8(1C), 129.3(1C) , 129.5(2C), 130.5(2C), 130.7(2C), 135.1(1C), 136.5(1C), 137.8(1C), 146.4(1C), 155.7(1C), 156.7(1C).

[0068] Example 4

[0069] The epoxy resin composition was prepared according to the following method:

[0070] Prepare components A and B separately:

[0071] Component A: Mix 52g of epoxy resin WSR618, 38g of calcium carbonate, and 10g of benzyl alcohol evenly.

[0072] Component B: 45g of polyamine 1#, 7g of polyetheramine 35g benzyl alcohol, 13g Mix thoroughly.

[0073] Components A and B were mixed evenly at a mass ratio of 1.5:1 to obtain an epoxy resin composition. Test samples were prepared according to the standard, and the performance test results are shown in Table 2.

[0074] Example 5

[0075] The epoxy resin composition was prepared according to the following method:

[0076] Prepare components A and B separately:

[0077] Component A: Mix 45g of epoxy resin WSR618, 45g of silica, and 10g of xylene evenly.

[0078] Component B: 38g of polyamine 2#, 8g of polyetheramine D-400, 40g xylene, 14g Mix thoroughly.

[0079] Components A and B were mixed evenly at a mass ratio of 1:1 to obtain an epoxy resin composition. Test samples were prepared according to the standard, and the performance test results are shown in Table 2.

[0080] Example 6

[0081] The epoxy resin composition was prepared according to the following method:

[0082] Prepare components A and B separately:

[0083] Component A: Mix 58g of epoxy resin WSR618, 31g of aluminum powder, and 11g of n-butyl glycidyl ether evenly.

[0084] Component B: 48g of polyamine 3# and 6g of polyetheramine T-403, 36g n-butyl glycidyl ether, 10g Mix thoroughly.

[0085] Components A and B were mixed evenly at a mass ratio of 2:1 to obtain an epoxy resin composition. Test samples were prepared according to the standard, and the performance test results are shown in Table 2.

[0086] Example 7

[0087] The epoxy resin composition was prepared according to the following method:

[0088] Prepare components A and B separately:

[0089] Component A: Mix 47g of epoxy resin WSR618, 45g of talc, and 8g of allyl glycidyl ether evenly.

[0090] Component B: 48g of polyamine 1#, 7g of polyetheramine 30g allyl glycidyl ether, 15g Mix thoroughly.

[0091] Components A and B were mixed evenly at a mass ratio of 1.5:1 to obtain an epoxy resin composition. Test samples were prepared according to the standard, and the performance test results are shown in Table 2.

[0092] Comparative Example 1

[0093] The epoxy resin composition was prepared using the method of Example 4, except that 4-[(4-aminocyclohexane)methyl]aniline was used to replace the secondary amine 1# in component B. Since 4-[(4-aminocyclohexane)methyl]aniline in the formulation crystallizes and precipitates at room temperature, the system has poor compatibility and cannot obtain a uniformly cured paint film and sample. Therefore, 4-[(4-aminocyclohexane)methyl]aniline that has not been heated and melted is difficult to use.

[0094] Comparative Example 2

[0095] The epoxy resin composition was prepared using the method of Example 4, except that polyetheramine was used. The performance test results of the epoxy resin composition after replacing the secondary amine 1# in component B are shown in Table 2.

[0096] Comparative Example 3

[0097] An epoxy resin composition was prepared using the method of Example 4, except that diethylenetriamine was used to replace the secondary amine 1# in component B. The performance test results of this epoxy resin composition are shown in Table 2.

[0098] Table 2 Performance test results of epoxy resin compositions

[0099]

[0100] Results analysis:

[0101] Examples 4-7 used the liquefied polyamine prepared according to the present invention to prepare epoxy resin compositions, while Comparative Examples 1-3 used other amine curing agents to prepare epoxy resin compositions. Specifically, Comparative Example 1 used unmodified 4-[(4-aminocyclohexane)methyl]aniline. As shown in Table 2, compared to Comparative Example 2, the gel time of Examples 4-7 was significantly shortened, and the curing activity was significantly improved. Comparative Example 3 had relatively high activity, but the film toughness was too low, making it extremely fragile and unsuitable for practical application.

[0102] The light transmittance of a paint film can characterize the gloss of the coating. The higher the light transmittance, the better the gloss. Conversely, when the coating surface absorbs moisture and turns white, the light transmittance is close to 0. As shown in Table 2, among the four specific implementation examples, the paint film gloss of Examples 4-7 has a significant advantage.

[0103] According to the national standard GB / T 1732-1993 "Test Method for Impact Resistance of Coating Film", the toughness of the coating film can be determined using a drop hammer impact tester. The higher the drop hammer impact height that the coating film can withstand, the better its toughness. As can be seen from Table 2, compared with Comparative Example 3, the toughness of the coating films in Examples 4-7 is significantly improved.

[0104] Impact strength is a key mechanical performance indicator that customers are concerned about. The impact resistance of Examples 4-7 is also significantly better than that of Comparative Examples 2-3.

[0105] In summary, the epoxy resin coating prepared by the liquefied polyamine of this invention has a fast curing speed, high gloss, good toughness, and excellent impact resistance after curing, resulting in superior overall performance.

[0106] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A liquefied polyamine, characterized in that, The polyamine has one of the following structures:

2. A method for preparing the liquefied polyamine of claim 1, characterized in that, In the method described, 4-[(4-aminocyclohexane)methyl]aniline undergoes a condensation reaction with M-[(Z)-8-pentadecanenyl]phenol and aldehyde to obtain a liquefied polyamine.

3. The method according to claim 2, characterized in that, In the method described above, the molar ratio of 4-[(4-aminocyclohexane)methyl]aniline to M-[(Z)-8-pentadecanenyl]phenol and aldehyde is 1:(1-2.5):(1-2.5). And / or, the aldehyde in the method is formaldehyde; And / or, the condensation reaction in the method is carried out at a temperature of 90-160℃ for 2-5 hours.

4. The method according to claim 2, characterized in that, The aldehyde in the method is an aqueous formaldehyde solution and / or paraformaldehyde.

5. An epoxy resin composition comprising the liquefied polyamine of claim 1, or comprising the liquefied polyamine prepared by any one of claims 2-4, characterized in that, The composition comprises component A and component B in a mass ratio of (1-2):1; Wherein, taking the total mass of component A as 100%, component A comprises the following raw materials: Epoxy resin 45-58wt% 31-45 wt% of filler Diluent 8-11 wt%; Based on a total mass of 100% for component B, component B comprises the following raw materials:

6. The composition according to claim 5, characterized in that, The epoxy resin in component A is selected from one or more of glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, and alicyclic epoxy resins. And / or, the filler in component A is selected from one or more of calcium carbonate, silica, aluminum powder, talc, mica powder, and kaolin; And / or, the diluent in component A is selected from one or more of benzyl alcohol, xylene, n-butyl glycidyl ether, allyl glycidyl ether, and butanediol diglycidyl ether.

7. The composition according to claim 5, characterized in that, The polyetheramine in component B is selected from... 8100 D-400 One or more of the T-403; And / or, the diluent in component B is selected from one or more of benzyl alcohol, xylene, n-butyl glycidyl ether, allyl glycidyl ether, and butanediol diglycidyl ether; And / or, the accelerator in component B is selected from nonylphenol, 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, DMCHA, One or more of PMDETA.

8. Use of an epoxy resin composition, said composition comprising the liquefied polyamine of claim 1, or said composition comprising the liquefied polyamine prepared by any one of claims 2-4, or said composition being the epoxy resin composition of any one of claims 5-7, characterized in that, The composition is used as an epoxy primer for automotive surfaces, a mid-coat for concrete floors, an anti-corrosion coating for tanks and pipelines, and an epoxy resin-based composite material.

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