A method for preparing amine-modified epoxy acrylate

Abstract

This invention discloses a method for preparing amine-modified epoxy acrylate. First, an organic amine is reacted with an epoxy resin at room temperature to undergo a ring-opening reaction to obtain an amine-modified epoxy resin. Then, a carboxyacrylate and a polymerization inhibitor are added to continue the reaction, yielding the amine-modified epoxy acrylate. The amine-modified epoxy acrylate prepared by this method exhibits superior adhesion, better heat resistance and flexibility, and higher reactivity. The amine-modified epoxy acrylate prepared by this method demonstrates excellent overall performance and achieves good technical results.

Description

Technical Field

[0001] This invention belongs to the field of ultraviolet curable materials technology, specifically relating to a method for preparing amine-modified epoxy acrylate. Background Technology

[0002] Ultraviolet (UV) curing is an advanced material surface treatment technology that emerged in the 1960s. It, along with electron beam (EB) curing, is collectively known as radiation curing. UV curing utilizes ultraviolet light to initiate the rapid polymerization and cross-linking of chemically active liquid materials, instantly curing them into solid materials.

[0003] Photopolymerization technology is a highly efficient, environmentally friendly, energy-saving, and high-quality material surface treatment technology. With its 5E characteristics—efficient, adaptable, economical, energy-saving, and environmentally friendly—it is hailed as a new technology for green industry in the 21st century. Among photopolymers, epoxy acrylates are the most widely used and consumed type. Based on different structural types, they can be divided into standard bisphenol A epoxy acrylates, phenolic epoxy acrylates, etc. Standard bisphenol A epoxy acrylates contain benzene rings in their molecules, giving the resin good heat resistance, strength, and hardness. Simultaneously, the hydroxyl groups in the side chains enhance adhesion.

[0004] Standard bisphenol A epoxy acrylates have a wide range of raw material sources, excellent heat resistance, and fast curing speed, making them widely used in plastics, wood flooring, paper, and other fields. However, standard bisphenol A epoxy acrylates themselves have several drawbacks, including large volume shrinkage, poor adhesion, and brittle cured film, which limit their applications. To improve these shortcomings, many researchers have modified their structure, resulting in modified epoxy acrylates.

[0005] Currently, modified epoxy acrylates on the market have effectively improved the defects of standard bisphenol A epoxy acrylates, such as reduced volume shrinkage, enhanced adhesion, and increased flexibility of the cured film. However, they have also created new problems, including significantly reduced reactivity and slow curing speed. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a novel synthetic route to prepare an amine-modified epoxy acrylate with good heat resistance, good adhesion, good flexibility, and high reactivity.

[0007] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0008] A method for preparing an amine-modified epoxy acrylate includes the following steps:

[0009] (1) An amine-modified epoxy resin was obtained by ring-opening reaction of organic amine with liquid epoxy resin.

[0010] (2) Add carboxylated acrylate and polymerization inhibitor, and continue the reaction by heating to obtain amine-modified epoxy acrylate.

[0011] As a preferred embodiment, in the above-described method for preparing an amine-modified epoxy acrylate, the organic amine in step (1) is selected from one or more of diethylamine, dipropylamine, dibutylamine, and diethanolamine; and the epoxy resin is selected from one or more of Jiangsu Sanmu SM828, SM827, SM128, and Taiwan Nanya 128 and 127.

[0012] As a preferred embodiment, the preparation method of the amine-modified epoxy acrylate described above, wherein the synthesis method of the amine-modified epoxy resin in step (1) is as follows: put the epoxy resin into a glass flask, place it in an ice-water bath, slowly add organic amine, control the reaction temperature to not exceed 15°C (preferably 5°C to 15°C in the embodiments of the present invention, and most preferably 10°C to 15°C), and after the addition is complete, slowly raise it to room temperature and continue the reaction for 5 hours.

[0013] As a preferred embodiment, the above-described method for preparing amine-modified epoxy acrylate controls the molar ratio of epoxy groups in epoxy resin, active hydrogen NH in organic amine, and carboxyl groups in carboxyl acrylate to be 2.0:0.5:1.5~2.0:1.5:0.5.

[0014] As a preferred embodiment, in the above-described method for preparing an amine-modified epoxy acrylate, the carboxyacrylate in step (2) is selected from one or more of acrylic acid, methacrylic acid, and β-acryloyloxypropionic acid; the polymerization inhibitor is selected from one or more of hydroquinone, p-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxytoluene, and phenothiazine; and the mass of the polymerization inhibitor accounts for 0.08% to 0.30% of the total mass of all materials.

[0015] As a preferred embodiment, the preparation method of the amine-modified epoxy acrylate described above, wherein the synthesis method of the amine-modified epoxy acrylate in step (2) is as follows: adding carboxylated acrylate and polymerization inhibitor to the amine-modified epoxy resin in step (1), slowly heating to 100℃~120℃ to continue the reaction until the acid value is not higher than 4mgKOH / g.

[0016] The beneficial effects of this invention are as follows:

[0017] Standard bisphenol A epoxy acrylate, as the most widely used photocurable resin, has advantages such as good heat resistance and fast curing speed, but it also has defects such as large volume shrinkage, poor adhesion, and brittle cured film. Modified epoxy acrylate improves these defects, but at the same time introduces new problems, including significantly reduced reactivity and slower curing speed.

[0018] This invention proposes a method for preparing amine-modified epoxy acrylate. The amine-modified epoxy acrylate prepared by this method effectively improves the technical defects of standard bisphenol A epoxy acrylate and modified epoxy acrylate, and has the advantages of good heat resistance, good adhesion, good flexibility and high reactivity. Detailed Implementation

[0019] Example 1

[0020] An amine-modified epoxy acrylate is prepared by the following steps:

[0021] (1) 372 g of epoxy resin SM828 (containing 2.0 moles of epoxy groups) was added to a reaction flask, stirred, and cooled with an ice-water bath. 105.1 g of diethanolamine (containing 1.0 moles of nitrogen-containing active hydrogen NH) was gradually added dropwise, with the temperature controlled not to exceed 15°C during the addition. If the temperature rise was obvious, the addition rate was slowed down until it stopped. After the temperature stabilized below 15°C, the addition was continued. After the addition was completed, the temperature was slowly raised to room temperature, and the reaction was continued for 5 hours to obtain amine-modified epoxy resin 1.

[0022] (2) Add 0.8 g of p-hydroxyanisole and 72.1 g of acrylic acid (containing 1.0 mole of carboxyl group) to the above amine-modified epoxy resin 1, and slowly heat to 110°C to continue the reaction until the acid value is not higher than 4 mg KOH / g, to obtain amine-modified epoxy acrylate 1.

[0023] Example 2

[0024] An amine-modified epoxy acrylate is prepared by the following steps:

[0025] (1) Add 364 g of epoxy resin SM827 (containing 2.0 moles of epoxy groups) to a reaction flask, start stirring, cool with an ice-water bath, and gradually add 87.7 g of diethylamine (containing 1.2 moles of nitrogen-containing active hydrogen NH). During the addition, control the temperature to not exceed 15°C. If the temperature rises significantly, slow down the addition rate until it stops. After the temperature stabilizes below 15°C, continue adding. After the addition is complete, slowly raise the temperature to room temperature and continue the reaction for 5 hours to obtain amine-modified epoxy resin 2.

[0026] (2) Add 0.7 g hydroquinone and 115.2 g β-acryloyloxypropionic acid (containing 0.8 moles of carboxyl groups) to the above amine-modified epoxy resin 2, and slowly heat to 115 °C to continue the reaction until the acid value is not higher than 4 mg KOH / g, to obtain amine-modified epoxy acrylate 2.

[0027] Example 3

[0028] An amine-modified epoxy acrylate is prepared by the following steps:

[0029] (1) Add 372 g of epoxy resin Nanya 128 (containing 2.0 moles of epoxy groups) to a reaction flask, start stirring, cool with an ice-water bath, and gradually add 77.5 g of dibutylamine (containing 0.6 moles of nitrogen-containing active hydrogen NH). During the addition process, control the temperature to not exceed 15°C. If the temperature rises significantly, slow down the addition rate until it stops. After the temperature stabilizes below 15°C, continue adding. After the addition is complete, slowly raise the temperature to room temperature and continue the reaction for 5 hours to obtain amine-modified epoxy resin 3.

[0030] (2) Add 0.6 g of phenothiazine and 120.5 g of methacrylic acid (containing 1.4 moles of carboxyl groups) to the above-mentioned amine-modified epoxy resin 3, and slowly heat to 120°C to continue the reaction until the acid value is not higher than 4 mg KOH / g, to obtain amine-modified epoxy acrylate 3.

[0031] Performance testing

[0032] The amine-modified epoxy acrylates 1, 2, and 3 prepared in Examples 1-3 above, standard bisphenol A epoxy acrylate CN104 (produced by Sartoma, USA), modified epoxy acrylate SM6100D (produced by Jiangsu Sanmu Chemical Co., Ltd.), tripropylene glycol diacrylate TPGDA (produced by Chang Hsing Chemical, Taiwan, China), and photoinitiator 1173 (produced by Tianjin Jiuri) were formulated according to the formula in Table 1 to obtain photocurable coating samples.

[0033] Table 1 Formulation of UV-curable coatings

[0034]

[0035] Take the prepared coating samples from Table 1 (UV-curable coating formulation 1#, UV-curable coating formulation 2#, UV-curable coating formulation 3#, UV-curable coating formulation 4#, and UV-curable coating formulation 5#), and apply each to a tinplate using a wire rod to obtain a coating film with a thickness of approximately 20 micrometers. Irradiate the coating film with a mercury lamp light source, and measure the number of passes required for the UV-curable coating to reach surface dryness, light adhesion, heat resistance, and flexibility. The results are shown in Table 2.

[0036] Table 2 Comparison of the properties of cured films of UV-curable coatings

[0037]

[0038] The number of passes required to reach surface dryness is the number of times the paint film is repeatedly passed through the machine under a constant mercury lamp irradiation intensity until it reaches a non-sticky state. The fewer passes required to reach surface dryness, the higher the reactivity.

[0039] Adhesion was tested according to the method described in the national standard GB / T 9286-2021 "Cross-cut test for paints and varnishes". The higher the value, the worse the adhesion.

[0040] Heat resistance test method: Place the paint film in a 150℃ oven for 12 hours, cool to room temperature, and then test the adhesion according to the method described in national standard GB / T 9286-2021 "Paints and Varnishes - Cross-cut Test". The higher the value, the worse the heat resistance.

[0041] The flexibility was tested according to the method described in the national standard GB / T 1731-2020 "Determination of Flexibility of Paint Film and Putty Film". The higher the value, the worse the flexibility.

[0042] The experimental results in Table 2 show that, compared with standard bisphenol A epoxy acrylate CN104 and modified epoxy acrylate SM6100D, the amine-modified epoxy acrylate prepared by the method of this invention exhibits superior adhesion, better heat resistance and flexibility, and higher reactivity. The amine-modified epoxy acrylate prepared by the method of this invention demonstrates excellent overall performance and achieves good technical results.

Claims

1. A method for preparing amine-modified epoxy acrylate, characterized in that, Includes the following steps: (1) An amine-modified epoxy resin was obtained by ring-opening reaction of organic amine with liquid epoxy resin. (2) Add carboxyacrylate and polymerization inhibitor to step (1), and continue the reaction by heating to obtain amine-modified epoxy acrylate.

2. The method for preparing an amine-modified epoxy acrylate according to claim 1, characterized in that, The organic amine in step (1) is selected from one or more of diethylamine, dipropylamine, dibutylamine, and diethanolamine; the epoxy resin is selected from one or more of Jiangsu Sanmu epoxy resin SM828, epoxy resin SM827, epoxy resin SM128, Taiwan Nanya epoxy resin 128, and epoxy resin 127.

3. The method for preparing an amine-modified epoxy acrylate according to claim 1, characterized in that, The synthesis method of the amine-modified epoxy resin in step (1) is as follows: put the epoxy resin into a glass flask and place it in an ice-water bath, slowly add the organic amine, control the reaction temperature to not exceed 15°C, and after the addition is complete, slowly raise it to room temperature and continue the reaction for 5 hours.

4. The method for preparing an amine-modified epoxy acrylate according to claim 1, characterized in that, The molar ratio of epoxy groups in epoxy resin, active hydrogen NH in organic amine, and carboxyl groups in carboxyacrylate is controlled to be 2.0:0.5:1.5~2.0:1.5:0.

5.

5. The method for preparing an amine-modified epoxy acrylate according to claim 1, characterized in that, The carboxyacrylate in step (2) is selected from one or more of acrylic acid, methacrylic acid, and β-acryloyloxypropionic acid; the polymerization inhibitor is selected from one or more of hydroquinone, p-hydroxyanisole, 3,5-ditert-butyl-4-hydroxytoluene, and phenothiazine; the polymerization inhibitor accounts for 0.08% to 0.30% of the total mass of all materials.

6. The method for preparing an amine-modified epoxy acrylate according to claim 1, characterized in that, The synthesis method of the amine-modified epoxy acrylate in step (2) is as follows: add carboxylated acrylate and polymerization inhibitor to the amine-modified epoxy resin in step (1), slowly raise the temperature to 100℃~120℃, and continue the reaction at a temperature of 100℃~120℃ until the acid value is not higher than 4mgKOH / g.

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