A polysecondary amine and a method for its preparation and use

Abstract

The application provides a poly-sec-amines, a preparation method and application thereof. The poly-sec-amines have long aliphatic chain segments, good flexibility and excellent hydrophobicity. Meanwhile, hydroxyl groups are introduced into the molecules, so that the curing process can be greatly accelerated when the poly-sec-amines are used as epoxy resin curing agents, and the curing speed of the epoxy resin is obviously improved. The epoxy resin composition containing the poly-sec-amines can not only realize rapid curing, but also has high surface gloss and good flexibility, so as to meet the needs of the paint industry.

Description

Technical Field

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

[0002] Coatings are liquid or solid materials that, when applied to the surface of an object using different construction techniques, can form a firmly adhering solid film under certain conditions. These films provide protection, decoration, or other functions (such as insulation, heat resistance, and marking). Coatings are indispensable materials in industrial and agricultural production, national defense technology, and people's daily lives. With the rapid development of the national economy, especially in the construction, home decoration, automotive, shipbuilding, and bridge industries, the application fields of coatings have become more extensive, and at the same time, new requirements have been placed on 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 high curing activity, good film flexibility, and high gloss. Summary of the Invention

[0008] The purpose of this invention is to provide a polyamine for coatings. This polyamine molecule contains a long aliphatic chain segment, thus exhibiting good flexibility and excellent hydrophobic properties. At the same time, the introduction of hydroxyl groups into the molecule can greatly accelerate the curing process when used as an epoxy resin curing agent, significantly improving the curing speed of epoxy resin.

[0009] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0010] A poly-secondary amine having the following structure:

[0011]

[0012] Where n = 0 or 1,

[0013] R3, R4, and R5 represent H, H, and H, respectively. H, H, or H, H.

[0014] This invention provides a novel polyamine with a long aliphatic chain segment, exhibiting good flexibility. Compared to easily hygroscopic small-molecule amines, it possesses superior hydrophobic properties. Furthermore, the introduction of hydroxyl groups into the molecule significantly enhances the curing speed when used as an epoxy resin curing agent. Aminophenol, being a solid powder, requires melting at temperatures above 170°C for use as an epoxy curing agent. This invention modifies it into a liquid polyamine with a viscosity below 500 mPa·s, allowing direct mixing with epoxy resin without heating, greatly reducing energy costs and making the construction process highly efficient and convenient.

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

[0016] A method for preparing the polyamine, the method comprising reacting aminophenol, acrylonitrile, a non-amino phenol, and an aldehyde to prepare the polyamine, includes the following steps:

[0017] S1: Aminophenol undergoes an addition reaction with acrylonitrile followed by hydrogenation;

[0018] S2: The product of reaction S1 undergoes a condensation reaction with phenols and aldehydes that do not contain amino groups to obtain the target product, a polyamine.

[0019] In this invention, the aminophenol in S1 is preferably 4-aminophenol and / or 2-aminophenol.

[0020] In this invention, S1 uses an acidic ion exchange resin to post-treat the addition reaction product to maintain the product's pH value as neutral.

[0021] In one embodiment, the structure of the intermediate product obtained in S1 is shown below:

[0022]

[0023] In this invention, the amino-free phenol in S2 is preferably M-[(Z)-8-pentadecanenyl]phenol and / or dodecylphenol; the aldehyde is preferably formaldehyde, more preferably an aqueous formaldehyde solution and / or paraformaldehyde;

[0024] In this invention, the temperature of the condensation reaction described in S2 is 70-150℃, and the reaction time is 1-5h.

[0025] Another objective of this invention is to provide an epoxy resin composition that uses the aforementioned polyamine as a curing agent, which not only enables rapid curing but also produces a cured product with high surface gloss and good flexibility, thus meeting the new demands of the coatings industry.

[0026] An epoxy resin composition comprising the above-described polyamine, or comprising a polyamine prepared by the above-described method for preparing polyamines, wherein the composition comprises two components, A and B:

[0027] Component A comprises the following raw materials, based on a total mass of 100% of component A:

[0028] 40-50 wt% epoxy resin

[0029] 42-55 wt% of filler

[0030] Diluent 4-8 wt%;

[0031] Component B comprises the following raw materials, based on a total mass of 100% of component B:

[0032]

[0033] The mass ratio of component A to component B is (3-5):1.

[0034] In this invention, the epoxy resin is selected from one or more of glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, and alicyclic epoxy resins.

[0035] In this invention, the filler is selected from one or more of calcium carbonate, silicon dioxide, aluminum powder, talc powder, mica powder, and kaolin.

[0036] 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.

[0037] In this invention, the polyetheramine is selected from... 8100 D-400 One or more of the T-403.

[0038] 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.

[0039] In this invention, the accelerator is selected from nonylphenol, 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, etc. DMCHA, One or more of PMDETA.

[0040] Another object of the present invention is to provide a use of an epoxy resin composition.

[0041] Use of an epoxy resin composition, wherein the composition comprises the above-mentioned poly-secondary amine, or the composition comprises a poly-secondary amine 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-base coat for concrete floors, and an anti-corrosion coating for tanks and pipelines.

[0042] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0043] (1) Aminophenol is a solid powder. As an epoxy curing agent, it needs to be melted at a high temperature of 170°C or higher. After the present invention modifies it into a liquid polyamine, the viscosity is less than 500 mPa·s. It can be directly mixed with epoxy resin without heating, which greatly reduces energy consumption costs and makes the construction process efficient and convenient.

[0044] (2) The polyamine of the present invention has good flexibility, excellent hydrophobic properties, and greatly improved curing speed.

[0045] (3) The addition reaction was post-treated with acidic ion exchange resin, which effectively prevented the decomposition of the product and improved the storage stability of the addition product.

[0046] (4) The prepared epoxy coating has a fast curing speed, good film flexibility, no moisture absorption and whitening phenomenon on the coating surface, and high gloss, which is in line with the industry development trend. Attached image description: Figure 1 The results of infrared characterization of aminophenol and intermediate products in Example 1 are shown below. Figure 2 The infrared characterization results are for the target product of Example 1. Detailed Implementation

[0047] The present invention will be further illustrated by specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0048] The raw materials and their sources are shown in Table 1:

[0049] Table 1 Raw Materials and Sources

[0050]

[0051] The performance evaluation method is as follows:

[0052] Gel time: Refer to GB / T 12007.7-1989 "Determination of gel time of epoxy resin";

[0053] Light transmittance: Refer to ASTM D1746-2015 Standard Test Method for Transparency of Plastic Sheets;

[0054] Film toughness: Refer to GB / T 1732-1993 Test method for impact resistance of paint film.

[0055] Chemical resistance: In the field of epoxy resins, the swelling ratio η is used to characterize the chemical resistance of epoxy resins. The larger the η, the worse the chemical resistance. Cured epoxy resin is made into small cubes of 15mm × 15mm × 15mm, completely dried in an oven, and weighed. Then, it is soaked in 10% hydrochloric acid, 10% acetic acid, and 10% ethanol at room temperature for 14 days respectively. After drying the surface, it is weighed again, and the swelling ratio η is calculated using the following formula:

[0056] η = (m - m0) / m0 × 100%

[0057] In the formula, m is the mass of the sample after soaking for 14 days, in grams;

[0058] m0 - Mass of the sample block before soaking, in g;

[0059] Fourier Transform Infrared Spectroscopy (FTIR): The synthesis process of polyamines was characterized using total reflectance ATR-FTIR. The spectrometer was a Thereto Scientific Nicolet 5700 (USA), with a scanning range of 4000-400 cm⁻¹. -1 .

[0060] Example 1

[0061] Polyamine 1# was prepared according to the following method:

[0062] Under nitrogen protection, the reaction temperature was controlled at 80℃. Acrylonitrile (2 mol) was added dropwise to a mixture of p-aminophenol (1 mol) and NaOH aqueous solution (concentration 1 wt%) (the total mass ratio of acrylonitrile + p-aminophenol to NaOH solution was 1:2). After the addition was completed, the reaction was maintained at this temperature for 2 hours. The residual monomer was removed by vacuum distillation (90℃, absolute pressure 2 kPa). The product was then post-treated with acidic ion exchange resin (the product was repeatedly passed through the column at a flow rate of 4 m / h until the outlet liquid pH = 7, yielding an intermediate product). Catalytic hydrogenation was then performed (using 2 wt% Raney nickel catalyst RC-211 (Jiangsu Raney Metal Technology Co., Ltd.), 6 MPa hydrogen, and a reaction temperature of 98℃). The product was then condensed with M-[(Z)-8-pentadecanyl]phenol and paraformaldehyde at 90℃ for 2 hours (the molar ratio of hydrogenation product, M-[(Z)-8-pentadecanyl]phenol, and paraformaldehyde was controlled at 1:2). 2) Remove moisture by vacuum evaporation (90℃, absolute pressure 2kPa) to obtain the target product, polyamine 1#, with a viscosity of 452mPa·s.

[0063] The infrared characterization results of p-aminophenol, intermediate products, and target products are shown in the figure. Figure 1 and Figure 2 .

[0064] Example 2

[0065] Polyamine 2# was prepared according to the following method:

[0066] Under nitrogen protection, the reaction temperature was controlled at 80℃. Acrylonitrile (2 mol) was added dropwise to a mixture of o-aminophenol (1 mol) and NaOH aqueous solution (concentration 1 wt%) (the total mass ratio of acrylonitrile + o-aminophenol to NaOH solution was 1:2). After the addition was completed, the reaction was maintained at this temperature for 2 hours. Residual monomers were removed by vacuum distillation (90℃, absolute pressure 2 kPa). The product was then post-treated with an acidic ion exchange resin (the product was repeatedly passed through the column at a flow rate of 4 m / h until the outlet liquid pH = 7, yielding an intermediate product). Catalytic hydrogenation was then performed (using 2 wt% Raney nickel catalyst RC-211 (Jiangsu Raney Metal Technology Co., Ltd.) and 6 MPa hydrogen gas). The product was then condensed with dodecylphenol and formaldehyde aqueous solution at 70℃ for 5 hours (the molar ratio of hydrogenation product, dodecylphenol, and formaldehyde was controlled at 1:2:2). Moisture was removed by vacuum distillation (90℃, absolute pressure 2 kPa) to obtain the target product, polyamine 2#, with a viscosity of 456 mPa. s.

[0067] Example 3

[0068] Polyamine 3# was prepared according to the following method:

[0069] Under nitrogen protection, the reaction temperature was controlled at 80℃. Acrylonitrile (2 mol) was added dropwise to a mixture of p-aminophenol (1 mol) and NaOH aqueous solution (concentration 1 wt%) (the total mass ratio of acrylonitrile + p-aminophenol to NaOH solution was 1:2). After the addition was completed, the reaction was kept at this temperature for 2 hours, followed by vacuum distillation (90℃, absolute pressure 2 kPa). After removing residual monomers, the product was post-treated with acidic ion exchange resin (the product was repeatedly passed through the column at a flow rate of 4 m / h until the outlet liquid pH = 7, yielding an intermediate product). Then, it underwent catalytic hydrogenation (using 2 wt% Raney nickel catalyst RC-211 (Jiangsu Raney Metal Technology Co., Ltd.) and 6 MPa hydrogen gas), followed by a condensation reaction with M-[(Z)-8-pentadecanyl]phenol and paraformaldehyde at 150℃ for 1 h (controlling the molar ratio of hydrogenation product, M-[(Z)-8-pentadecanyl]phenol, and paraformaldehyde to 1:2:2). Moisture was removed under reduced pressure (90℃, absolute pressure 2 kPa) to obtain the target product, polyamine 3#, with a viscosity of 459 mPa·s.

[0070] Example 4

[0071] The epoxy resin composition was prepared according to the following method:

[0072] Prepare components A and B separately:

[0073] Component A: Mix 45g of epoxy resin ZW-2895, 48g of calcium carbonate, and 7g of benzyl alcohol evenly.

[0074] Component B: 40g of polyamine 1#, 10g of polyetheramine 8100, 35g benzyl alcohol, 15g Mix DMCHA thoroughly.

[0075] Components A and B were mixed evenly at a mass ratio of 4:1 to obtain an epoxy resin composition. Test samples were prepared according to the standard, and the performance test results are shown in Table 2.

[0076] Example 5

[0077] The epoxy resin composition was prepared according to the following method:

[0078] Prepare components A and B separately:

[0079] Component A: Mix 40g of epoxy resin ZW-2895, 55g of silica, and 5g of xylene thoroughly.

[0080] Component B: 35g of polyamine 2#, 12g of polyetheramine D-400, 40g benzyl alcohol, 13g Mix PMDETA thoroughly.

[0081] Components A and B were mixed evenly at a mass ratio of 3:1 to obtain an epoxy resin composition. Test samples were prepared according to the standard, and the performance test results are shown in Table 2.

[0082] Example 6

[0083] The epoxy resin composition was prepared according to the following method:

[0084] Prepare components A and B separately:

[0085] Component A: Mix 50g of epoxy resin ZW-2895, 42g of talc, and 8g of n-butyl glycidyl ether until homogeneous.

[0086] Component B: 44g of polyamine 3#, 8g of polyetheramine T-403, 40g n-butyl glycidyl ether, and 8g nonylphenol are mixed evenly.

[0087] Components A and B were mixed evenly at a mass ratio of 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.

[0088] Example 7

[0089] The epoxy resin composition was prepared according to the following method:

[0090] Prepare components A and B separately:

[0091] Component A: Mix 50g of epoxy resin ZW-2895, 46g of aluminum powder, and 4g of allyl glycidyl ether evenly.

[0092] Component B: 45g of polyamine 3#, 8g of polyetheramine 8100, 39g allyl glycidyl ether, and 8g 2,4,6-tris(dimethylaminomethyl)phenol are mixed evenly.

[0093] Components A and B were mixed evenly at a mass ratio of 3.5:1 to obtain an epoxy resin composition. Test samples were prepared according to the standard, and the performance test results are shown in Table 2.

[0094] Example 8

[0095] The epoxy resin composition was prepared according to the following method:

[0096] Prepare components A and B separately:

[0097] Component A: Mix 45g of epoxy resin ZW-2895, 48g of mica powder, and 7g of butanediol diglycidyl ether evenly.

[0098] Component B: 43g of polyamine 2#, 12g of polyetheramine D-400, 30g butylene glycol diglycidyl ether, and 15g benzyl dimethylamine are mixed evenly.

[0099] Components A and B were mixed evenly at a mass ratio of 4.5:1 to obtain an epoxy resin composition. Test samples were prepared according to the standard, and the performance test results are shown in Table 2.

[0100] Example 9

[0101] The epoxy resin composition was prepared according to the following method:

[0102] Prepare components A and B separately:

[0103] Component A: Mix 40g of epoxy resin ZW-2895, 55g of kaolin, and 5g of benzyl alcohol evenly.

[0104] Component B: 44g of polyamine 1#, 8g of polyetheramine 8100, 40g benzyl alcohol, 8g Mix DMCHA thoroughly.

[0105] Components A and B were mixed evenly at a mass ratio of 3:1 to obtain an epoxy resin composition. Test samples were prepared according to the standard, and the performance test results are shown in Table 2.

[0106] Comparative Example 1

[0107] 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 group are shown in Table 2, which replaces the polyamine 1# in component B with 8100.

[0108] Comparative Example 2

[0109] 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.

[0110] Comparative Example 3

[0111] An epoxy resin composition was prepared using the method of Example 4, except that isophorone diamine 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.

[0112] Table 2 Performance test results of epoxy resin compositions

[0113]

[0114] Results analysis:

[0115] Examples 4-9 use the polyamines prepared in this invention to prepare epoxy resin compositions, while Comparative Examples 2-4 use other amine curing agents to prepare epoxy resin compositions. As shown in Table 2, compared with Comparative Examples 1-3, the gel time of Examples 4-9 is greatly shortened and the curing activity is significantly improved.

[0116] 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 six specific implementation examples, the paint film gloss of Examples 4-9 also has advantages.

[0117] 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 Examples 1-3, the toughness of the coating films in Examples 4-9 is significantly improved.

[0118] In addition, the swelling ratio η characterizes the chemical resistance of epoxy resin. The larger the η, the worse the chemical resistance. The chemical resistance of Examples 4-9 in Table 2 is also quite good.

[0119] In summary, the polyamine prepared in this invention produces epoxy resin coatings with fast curing speed, high gloss, extremely high toughness, and excellent chemical resistance, resulting in superior overall performance.

[0120] 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 polyamine, characterized in that, The polyamine has the following structure: Where n = 0 or 1, R1= R2= R3, R4, and R5 are H, H, and H, respectively. ,or H, H, or H H.

2. A method for preparing the poly-secondary amine of claim 1, characterized in that, The method involves the reaction of aminophenol, acrylonitrile, non-amino phenol, and aldehyde, and includes the following steps: S1: Aminophenol undergoes an addition reaction with acrylonitrile followed by hydrogenation; S2: The product of reaction S1 undergoes a condensation reaction with phenols and aldehydes that do not contain amino groups to obtain the target product, a polyamine. Wherein, the aminophenol in S1 is 4-aminophenol and / or 2-aminophenol; The structural diagram of the S1 product is shown below: ； S1 uses acidic ion exchange resin to post-treat the addition reaction product to keep the product pH value neutral. Wherein, the amino-free phenol in S2 is M-[(Z)-8-pentadecanenyl]phenol and / or dodecylphenol; the aldehyde is formaldehyde; In S2, the molar ratio of the product of reaction S1, M-[(Z)-8-pentadecanenyl]phenol or dodecylphenol, and aldehyde is 1:2:

2.

3. The method according to claim 2, characterized in that, The condensation reaction described in S2 is carried out at a temperature of 70-150℃ for 1-5 hours.

4. The method according to claim 2, characterized in that, The aldehyde mentioned in S2 is an aqueous formaldehyde solution and / or paraformaldehyde.

5. An epoxy resin composition comprising the polyamine of claim 1, or comprising a polyamine prepared by any one of claims 2-4, characterized in that, The composition comprises two components, A and B: Component A comprises the following raw materials, based on a total mass of 100% of component A: 40-50wt% epoxy resin 42-55wt% of filler Diluent 4-8 wt% Component B comprises the following raw materials, based on a total mass of 100% of component B: Poly-secondary amines 35-45wt% 8-12 wt% polyetheramine Diluent 30-40wt% Accelerator 8-15wt%; The mass ratio of component A to component B is (3~5):

1.

6. The composition according to claim 5, characterized in that, The epoxy resin is selected from one or more of glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, and alicyclic epoxy resins; The filler is selected from one or more of calcium carbonate, silicon dioxide, aluminum powder, talc powder, mica powder, and kaolin. 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. The polyetheramine is selected from WANAMINE. ® 8100, JEFFAMINE ® D-400, JEFFAMINE ® One or more of the T-403; 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. The accelerator is selected from nonylphenol, 2,4,6-tris(dimethylaminomethyl)phenol, benzyldimethylamine, and WANAMINE. ® DMCHA, WANAMINE ® One or more of PMDETA.

7. Use of an epoxy resin composition, said composition comprising the poly-secondary amine of claim 1, or comprising the poly-secondary amine prepared by any one of claims 2-4, or said composition being the epoxy resin composition of claim 5 or 6, characterized in that, The composition is used as an epoxy primer for automotive surfaces, a mid-coat for concrete floors, and an anti-corrosion coating for tanks and pipelines.

Images