An ether epoxy toughening agent and its preparation method and application

Abstract

An ether-based epoxy toughening agent, its preparation method, and application are described. Its chemical structure is as follows: #imgabs0#, where n ranges from 3 to 40, and R represents a molecular structure containing a benzene ring, a condensed ring, or several rigid rings connected together. Adding a small amount of this epoxy toughening agent can significantly improve the flexibility of epoxy resin while maintaining its thermal properties, while also increasing its strength and modulus.

Description

Technical Field

[0001] The invention belongs to the field of epoxy resins, and particularly relates to an ether epoxy toughening agent and a preparation method and application thereof. Background Art

[0002] As a thermosetting resin, epoxy resin can undergo a curing reaction with curing agents such as amines and anhydrides to generate a three-dimensional network cross-linked structure. Due to its advantages such as excellent thermal stability, mechanical properties, insulation, high adhesion, and molding processability, it is now widely used in the fields of coatings, electronics, adhesives, composite materials, civil engineering, etc. However, since the cured product has a high cross-linked network structure, large internal stress, brittleness, and poor impact resistance, it is easy to be damaged when used directly, causing major dangerous accidents and economic losses. Therefore, it is particularly important to perform toughening modification on it. The epoxy toughening agents currently used are mainly rubber elastomers, interpenetrating network polymers, flexible curing agents, thermoplastic resins, hyperbranched polymers, thermotropic liquid crystal polymers, and core-shell particles. These methods more or less have some problems. For example, rubber elastomers, flexible curing agents, and block polymers can significantly improve the toughness of epoxy resins, but while toughening, the tensile strength, flexural strength, modulus, and glass transition temperature (T g ) and thermal properties. Hyperbranched polymers, for example, can avoid this problem, but their synthesis is complex and tedious, with high costs. The inevitable use of organic solvents during the synthesis process can cause serious environmental pollution. Nanofillers also have poor dispersibility and interfacial compatibility, which greatly limits the toughening and strengthening effects of nanofiller-modified epoxy resins. Therefore, to date, synthesizing epoxy toughening agents that significantly enhance the flexibility of epoxy resins while maintaining or even improving their heat resistance, strength, and modulus through simple, effective, and environmentally friendly methods remains a significant challenge. Summary of the Invention

[0003] Technical Problem Solved: To address the shortcomings of epoxy resins, such as high rigidity and brittleness, and to meet the requirements of sustainable green development, this invention discloses an ether-based epoxy toughening agent, its preparation method, and its application. Adding a small amount of this epoxy toughening agent can significantly improve the flexibility of epoxy resin while maintaining its thermal properties, while also increasing its strength and modulus.

[0004] Technical solution: An ether epoxy toughening agent, the chemical structure of which is as follows: The value of n ranges from 3 to 40, and R is a molecular structure containing a benzene ring, a condensed ring, or several rigid rings connected together.

[0005] The preferred chemical formula is: The value range of n is 5 to 7.

[0006] An ether epoxy toughening agent composition contains at least one compound in the above molecular structure.

[0007] The preparation method of an ether epoxy toughening agent comprises the following steps: mixing a polyetheramine and a monocarboxylic acid containing a rigid group in a molar ratio of (1-1.1):1, adding a catalyst accounting for 0.5wt.%-1wt.% of the total mass of the reactants, and reacting at 150-180°C for 4-6h to obtain the ether epoxy toughening agent.

[0008] The monocarboxylic acids containing rigid groups are benzoic acid, o-hydroxybenzoic acid, o-methylsalicylic acid, 4-methylsalicylic acid, acetylsalicylic acid, 5-acetylsalicylic acid, 4-nitrosalicylic acid, 5-methylsalicylic acid, 5-chlorosalicylic acid, 3,5-dinitrosalicylic acid, trisalicylic acid, 3-fluorosalicylic acid, 4-fluorosalicylic acid, 5-fluorosalicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 3-hydroxy-5-methylbenzoic acid, 2-(hydroxymethyl)benzoic acid, 3-hydroxymethylbenzoic acid, 4-hydroxy-2-methylbenzoic acid, 4-hydroxy-3-methylbenzoic acid, 5-hydroxy-2-methylbenzoic acid, 3-hydroxy-2-methylbenzoic acid, 4-hydroxy- Methylbenzoic acid, 2-hydroxy-6-methylbenzoic acid, 2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 3,5-dihydroxy-4-methylbenzoic acid, 2,3,4-trihydroxybenzoic acid, 2,3,5-trihydroxybenzoic acid, 2,3,6-trihydroxybenzoic acid, 2,4,5-trihydroxybenzoic acid, 2,4,6-trihydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid, abietic acid, dehydroabietic acid, 2-benzylbenzoic acid, 2-methoxybenzoic acid, 2-methyl-4-nitrobenzoic acid, 3 -(Chloromethyl)benzoic acid, 3-iodo-2-methylbenzoic acid, 3-chloro-5-methylbenzoic acid, 3-acetoxy-2-methylbenzoic acid, 3-(methoxymethyl)benzoic acid, 5-methyl-2-nitrobenzoic acid, 3-bromomethylbenzoic acid, 4-methoxy-3-methylbenzoic acid, 4-fluoro-2-methylbenzoic acid, 2,5-bis(trifluoromethyl)benzoic acid, 3,5-bis(trifluoromethyl)benzoic acid, 2-fluoro-4-trifluoromethylbenzoic acid, 3-trifluoromethylbenzoic acid, 3-fluoro-2-methylbenzoic acid, 4-methyl-3-nitrobenzoic acid, 2-fluoro-4-methylbenzoic acid, 4-(chloromethyl)benzoic acid, 4-(cyanomethyl)benzoic acid benzoic acid, 4-bromo-3-trifluoromethylbenzoic acid, 4-chloro-2-methylbenzoic acid, 4-methyl-3-(trifluoromethyl)benzoic acid, 4-trifluoromethylbenzoic acid, 4-cyano-2-trifluoromethylbenzoic acid, 3-methyl-4-nitrobenzoic acid, 3-fluoro-4-trifluoromethylbenzoic acid, 3-fluoro-5-(trifluoromethyl)benzoic acid, 2-chloro-4-fluorobenzoic acid, 3-bromo-4-methylbenzoic acid, 3-methyl-2-nitrobenzoic acid, 2-(bromomethyl)benzoic acid, o-methylbenzoic acid, m-methylbenzoic acid, 2,3-dimethoxybenzoic acid, 2,3,4-trimethoxybenzoic acid, 2,4,5-trimethylbenzoic acid, 3,5-Dinitro-o-methylbenzoic acid, o-formylbenzoic acid, o-ethoxybenzoic acid, 2-methyl-3-nitrobenzoic acid, 2-methyl-6-nitrobenzoic acid, 5-chloro-2-methylbenzoic acid, 5-fluoro-2-methylbenzoic acid, 2-fluoro-6-(trifluoromethyl)benzoic acid, 3-bromo-5-(trifluoromethyl)benzoic acid, 5-fluoro-2-(trifluoromethyl)benzoic acid, 3-bromo-2-methylbenzoic acid, 2-chloro-4-methylbenzoic acid, 2-bromo-6-methylbenzoic acid, 2,4,6-trimethylbenzoic acid, 3-cyanobenzoic acid, 2-nitrobenzoic acid, m-nitrobenzoic acid, p-nitrobenzoic acid Benzoic acid, 3-fluorobenzoic acid, 2-fluorobenzoic acid, p-fluorobenzoic acid, o-methylbenzoic acid, 3-trifluoromethyl-4-methoxybenzoic acid, 4-(trifluoromethylthio)benzoic acid, 4-butylbenzoic acid, 4-(4-methylpiperazine)benzoic acid, 2-hydroxyphenylacetic acid, 3-hydroxyphenylacetic acid, α-cyclohexylphenylacetic acid, α-bromophenylacetic acid, o-methylphenylacetic acid, 4-nitrophenylacetic acid, 4-(chloromethyl)phenylacetic acid, 3-methoxyphenylacetic acid, 3,4,5-trifluorophenylacetic acid, 4-(trifluoromethyl)phenylacetic acid, 4-hydroxyphenylacetic acid, 2-phenylphenylacetic acid, 4-methylthiophenylacetic acid, 2, 4-Dimethylphenylacetic acid, o-fluorophenylacetic acid, 3-fluorophenylacetic acid, p-fluorophenylacetic acid, 3,5-dimethylphenylacetic acid, 2-nitrophenylacetic acid, 2-methoxyphenylacetic acid, 2,4,5-trifluorophenylacetic acid, 3,4,5-trimethoxyphenylacetic acid, 4-methoxyphenylacetic acid, 1-naphthoic acid, 2-naphthoic acid, 2-hydroxy-3-naphthoic acid, 6-hydroxy-2-naphthoic acid, 1-hydroxy-2-naphthoic acid, 2-ethoxy-1-naphthoic acid, 3,7-dihydroxy-2-naphthoic acid, 2-methyl-1-naphthoic acid, 6-methoxynaphthoic acid, 4-methoxy-1-naphthoic acid, 4-methyl-1 -naphthoic acid, 6-hydroxy-1-naphthoic acid, 2-hydroxy-1-naphthoic acid, 3,5-dimethoxy-2-naphthoic acid, 4-ethyl-1-naphthoic acid, 3-methoxy-2-naphthoic acid, 6-acetoxy-2-naphthoic acid, 1,4-dihydroxy-2-naphthoic acid, 2-methoxy-1-naphthoic acid, 6-methoxy-2-naphthoic acid, 1,4-dimethoxy-2-naphthoic acid, 4-methoxy-1-naphthoic acid, 1-methoxy-2-naphthoic acid, 3,5-dimethoxy-2-naphthoic acid, 4,7-dimethoxy-1-naphthoic acid, 3,5-dihydroxy-2-naphthoic acid, 1,3-Dihydroxynaphthalene-2-carboxylic acid, 3-hydroxy-7-methoxy-2-naphthoic acid, 1-naphthylacetic acid, 2-naphthylacetic acid, 1-naphthyoxyacetic acid, 2-naphthyoxyacetic acid, 7-methoxy-1-naphthylacetic acid, 3-phenylacrylic acid, piperic acid, anacardic acid, DL-mandelic acid, sinapinic acid, furoic acid, caffeic acid, syringic acid, chlorogenic acid, mandelic acid, etodolac, tropic acid, α-boswellic acid, sulindac, komaric acid, DBCO-acid, At least one of oxolinic acid, neochlorogenic acid, isochlorogenic acid A, perillic acid, aceclofenac, α-cyclohexyl-DL-mandelic acid, 2-nicotinic acid, flufenamic acid, dichloroquinoline, rutinic acid, corosolic acid, mefenamic acid, ginkgolic acid, apoic acid, DBCO acid, glycyrrhetinic acid (α type), 4-coumaric acid, rosmarinic acid, rhein, aristolochic acid, ketorolac, benzyldalic acid, saccharin, kynurenic acid, and 4-methoxymandelic acid.

[0009] The polyetheramine is polyetheramine D230, polyetheramine D400, polyetheramine T403, polyetheramine D2000 or polyetheramine T5000.

[0010] The molar ratio of the polyetheramine to the monocarboxylic acid containing a rigid group is 1:1.

[0011] The catalyst is one of sodium hypophosphite monohydrate, phosphoric acid or orthophosphoric acid.

[0012] Application of the above-mentioned ether epoxy toughening agent in the preparation of epoxy resin.

[0013] The specific application method is to mix the prepared ether epoxy toughening agent with liquid epoxy resin for reaction, and then blend and cure with a low-temperature curing epoxy resin curing agent of equal stoichiometric ratio to obtain an ether epoxy toughening agent modified epoxy resin material.

[0014] Beneficial Effects: ① Adding a small amount of this ether-based epoxy toughening agent can impart very high elongation at break and toughness to epoxy resins, while also increasing their strength and modulus. ② The prepared ether-based epoxy toughening agent exhibits excellent compatibility with epoxy resins, avoiding issues such as phase separation that can lead to decreased transparency. ③ The preparation process for this ether-based epoxy toughening agent is simple, making it suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The infrared spectrum of the raw material polyetheramine;

[0016] Figure 2 This is the infrared spectrum of the ether epoxy toughening agent synthesized in Example 1. -1 Ether bond characteristic peak;

[0017] Figure 3This is the stress-strain curve of the cured product of modified epoxy resin E51 obtained in Example 4. DETAILED DESCRIPTION

[0018] The following examples are provided to further illustrate the present invention but are not intended to limit the present invention.

[0019] The curing agent in the embodiment is selected from: one of the epoxy curing agents that cure at medium and low temperatures, such as polyetheramine D230, polyetheramine D400, polyetheramine T403, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyethylenepolyamine, dipropylenetriamine, dimethylaminopropylamine, diethylaminopropylamine, trimethylhexamethylenediamine, dihexyltriamine, trimethylhexamethylenediamine, ethylenediamine, diethylamine, polythiol, dimethylaminopropylamine, aminoethylpiperazine, isophoronediamine, 1,2-diaminocyclohexane, methylenebiscyclohexylamine, and m-xylenediamine.

[0020] Example 1

[0021] Step 1: Add 80g of polyetheramine D400, 24.4g of benzoic acid, and 0.6g of sodium hypophosphite monohydrate to a 250mL four-necked flask equipped with a stirrer. Purge with nitrogen and react at 150°C for 5h. After the reaction, cool to room temperature to obtain the product, a polyetheramine-benzoic acid amide ether epoxy toughening agent.

[0022] Step 2: Take 2.5 g of the polyetheramine-benzoic acid amide prepared in step 1 and 97.5 g of epoxy resin (E51), react at 40°C for 12 h to obtain a modified epoxy resin.

[0023] 10 g of the obtained modified epoxy resin was added with 3 g of epoxy curing agent polyetheramine D230 and cured at 80° C. for 3 h.

[0024] Example 2

[0025] The reaction steps were the same as those in Example 1, except that the content of the ether epoxy toughening agent used to modify the epoxy resin was 5 g, and the content of the epoxy resin (E51) was 95 g.

[0026] Example 3

[0027] The reaction steps were the same as those in Example 1, except that the content of the ether epoxy toughening agent used to modify the epoxy resin was 7.5 g, and the content of the epoxy resin (E51) was 92.5 g.

[0028] Example 4

[0029] The reaction steps were the same as those in Example 1, except that the content of the ether epoxy toughening agent used to modify the epoxy resin was 10 g, and the content of the epoxy resin (E51) was 90 g.

[0030] Example 5

[0031] Step 1: Add 80g of polyetheramine D400, 27.6g of p-hydroxybenzoic acid, and 0.6g of phosphoric acid to a 250mL four-necked flask equipped with a stirrer. Purge with nitrogen and react at 150°C for 5 hours. After the reaction is complete, cool to room temperature to obtain the product, a polyetheramine-hydroxybenzoic acid amide ether epoxy toughening agent.

[0032] Step 2: Take 5 g of the polyetheramine-hydroxybenzoic acid amide prepared in step 1 and 95 g of epoxy resin, react at 40°C for 12 h to obtain a modified epoxy resin.

[0033] 10 g of the obtained modified epoxy resin (E51) was added with 3 g of epoxy curing agent polyetheramine D230 and cured at 80° C. for 3 h.

[0034] Example 6

[0035] The reaction steps were the same as those in Example 5, except that the content of the ether epoxy toughening agent used to modify the epoxy resin was 10 g, and the content of the epoxy resin (E51) was 90 g.

[0036] Example 7

[0037] Step 1: Add 80g of polyetheramine D400, 30.8g of 3,4-dihydroxybenzoic acid, and 0.6g of orthophosphoric acid to a 250mL four-necked flask equipped with a stirrer. Purge with nitrogen and react at 150°C for 5 hours. After the reaction, cool to room temperature to obtain the product, a polyetheramine-hydroxybenzoic acid amide ether epoxy toughening agent.

[0038] Step 2: Take 5 g of the polyetheramine-hydroxybenzoic acid amide prepared in step 1 and 95 g of epoxy resin (E51), react at 40°C for 12 h to obtain a modified epoxy resin.

[0039] 10 g of the obtained modified epoxy resin was added with 3 g of epoxy curing agent polyetheramine D230 and cured at 80° C. for 3 h.

[0040] Example 8

[0041] The reaction steps were the same as those in Example 7, except that the content of the ether epoxy toughening agent used to modify the epoxy resin was 10 g, and the content of the epoxy resin (E51) was 90 g.

[0042] Example 9

[0043] Step 1: Add 80g of polyetheramine D400, 30.8g of 3,4-dihydroxybenzoic acid, and 0.6g of orthophosphoric acid to a 250mL four-necked flask equipped with a stirrer. Purge with nitrogen and react at 150°C for 5 hours. After the reaction, cool to room temperature to obtain the product, a polyetheramine-hydroxybenzoic acid amide ether epoxy toughening agent.

[0044] Step 2: Take 2.5 g of the polyetheramine-hydroxybenzoic acid amide prepared in step 1 and 97.5 g of epoxy resin (E51), react at 40° C. for 12 h to obtain a modified epoxy resin.

[0045] 10 g of the obtained modified epoxy resin was added with 1.2 g of epoxy curing agent triethylenetetramine and cured at 50° C. for 4 h.

[0046] Example 10

[0047] Step 1: Add 80g of polyetheramine D400, 34g of 3,4,5-trihydroxybenzoic acid, and 0.6g of sodium hypophosphite monohydrate to a 250mL four-necked flask equipped with a stirrer. Purge with nitrogen and react at 150°C for 5 hours. After the reaction, cool to room temperature to obtain the product, a polyetheramine-hydroxybenzoic acid amide ether epoxy toughening agent.

[0048] Step 2: Take 5 g of the polyetheramine-hydroxybenzoic acid amide prepared in step 1 and 95 g of epoxy resin (E51), react at 40°C for 12 h to obtain a modified epoxy resin.

[0049] 10 g of the obtained modified epoxy resin was added with 3 g of epoxy curing agent polyetheramine D230 and cured at 80° C. for 3 h.

[0050] Example 11

[0051] The reaction steps were the same as those in Example 9, except that the content of the ether epoxy toughening agent used to modify the epoxy resin was 10 g, and the content of the epoxy resin (E51) was 90 g.

[0052] Comparative Example 1

[0053] 10g of epoxy resin (E51) was added with 3g of epoxy curing agent polyetheramine D230 and cured at room temperature.

[0054] Comparative Example 2

[0055] To 10 g of epoxy resin (E51), add 1.2 g of epoxy curing agent triethylenetetramine and cure at 50°C for 4 hours.

[0056] Comparative Example 3

[0057] Weigh 7.5 g of epoxidized soybean oil and 100 g of epoxy resin (E51) into a 250 mL four-necked flask, protect with nitrogen, heat to 130° C. and continue the reaction for 3 h to obtain the modified epoxy resin.

[0058] 10 g of the obtained modified epoxy resin was added with 3 g of epoxy curing agent polyetheramine D230 and cured at room temperature.

[0059] Comparative Example 4

[0060] Weigh 20 g of random carboxyl nitrile rubber and 100 g of epoxy resin (E51) into a 250 mL four-necked flask, protect with nitrogen, heat to 130° C. and continue the reaction for 3 h to obtain the modified epoxy resin.

[0061] 10 g of the obtained modified epoxy resin was added with 3 g of epoxy curing agent polyetheramine D230 and cured at room temperature.

[0062] Comparative Example 5

[0063] A random carboxylated tung nitrile rubber epoxy toughening agent was prepared according to the invention of CN201811531525.2. 35 g of random carboxylated nitrile rubber and 100 g of epoxy resin (E51) were weighed into a 250 mL four-necked flask. Under nitrogen protection, the temperature was raised to 130°C and the reaction was continued for 3 hours to obtain the modified epoxy resin.

[0064] 10 g of the obtained modified epoxy resin was added with 3 g of epoxy curing agent polyetheramine D230 and cured at room temperature.

[0065] Comparative Example 6

[0066] A random carboxyl tung nitrile rubber epoxy toughening agent was prepared according to the invention of CN201811531525.2. 45 g of random carboxyl nitrile rubber and 100 g of epoxy resin (E51) were weighed into a 250 mL four-necked flask. Under nitrogen protection, the temperature was raised to 130°C and the reaction was continued for 3 hours to obtain the modified epoxy resin.

[0067] 10 g of the obtained modified epoxy resin was added with 3 g of epoxy curing agent polyetheramine D230 and cured at room temperature.

[0068] Comparative Example 7

[0069] A polar carboxylated tung oil epoxy toughening agent was prepared according to patent CN201910540079.X. 30g of polar carboxylated tung oil and 100g of epoxy resin (E51) were weighed into a 250mL four-necked flask. Under nitrogen, the mixture was heated to 130°C and reacted for 3 hours to obtain the modified epoxy resin.

[0070] 10 g of the obtained modified epoxy resin was added with 3 g of epoxy curing agent polyetheramine D230 and cured at room temperature.

[0071] Table 1 Mechanical properties of modified epoxy resin cured products

[0072]

[0073]

[0074] Table 2 Thermal properties of modified epoxy resin cured products

[0075] Curing system (toughener content) <![CDATA[Glass transition temperature T g (°C)]]> Initial thermal decomposition temperature (℃) Example 1 (2.5%) 83.97 361.8 Example 2 (5%) 82.81 360.2 Example 3 (7.5%) 82.25 360.0 Example 4 (10%) 80.92 359.9 Example 5 (5%) 82.43 360.8 Example 6 (10%) 80.25 361.1 Example 7 (5%) 82.59 360.1 Example 8 (10%) 81.98 359.9 Example 9 (2.5%) 114.2 347.3 Example 10 (5%) 83.11 362.5 Example 11 (10%) 82.86 360.9 Comparative Example 1 (0%) 86.47 362.4 Comparative Example 2 (0%) 116.1 349.5 Comparative Example 3 (7.5%) 71.68 300.4 Comparative Example 4 (20%) 48.86 288.6 Comparative Example 5 (35%) 46.34 276.5 Comparative Example 6 (45%) 50.81 298.9 Comparative Example 7 (30%) 39.54 240.1

[0076] Because this ether epoxy toughening agent can form sacrificial hydrogen bonds with epoxy resin, only a small amount of this ether epoxy toughening agent needs to be added to significantly improve the flexibility of the epoxy resin, while also improving its strength and modulus and maintaining its excellent thermal properties. Its comprehensive toughness improvement effect is better than commercially available epoxidized soybean oil and random carboxyl nitrile rubber, and is also better than previous invention applications (CN201811531525.2, CN201910540079.X).

Claims

1. An ether epoxy toughening agent, characterized in that: The chemical structure is shown below: , wherein n is in the range of 3 to 40, and R is a benzene ring or o-hydroxyphenyl, m-hydroxyphenyl, p-hydroxyphenyl, 3-hydroxy-5-methylphenyl, 2-(hydroxymethyl)phenyl, 3-hydroxymethylphenyl, 4-hydroxy-2-methylphenyl, 4-hydroxy-3-methylphenyl, 5-hydroxy-2-methylphenyl, 3-hydroxy-2-methylphenyl, 4-hydroxymethylphenyl, 2-hydroxy-6-methylphenyl, 2,3-dihydroxyphenyl, 2,4-dihydroxyphenyl, 2,5-dihydroxyphenyl, 2,6-dihydroxyphenyl, 3,4-dihydroxyphenyl, 3,5-dihydroxyphenyl, 3,5-dihydroxy-4-methylphenyl, 2,3,4-trihydroxyphenyl, 2,3,5-trihydroxyphenyl, 2,3,6-trihydroxyphenyl, 2,4,5-trihydroxyphenyl, 2,4,6-trihydroxyphenyl, 3,4,5-trihydroxyphenyl.

2. The ether epoxy toughening agent according to claim 1, characterized in that: The chemical structural formula is: , the value range of n is 5~7.

3. An ether epoxy toughening agent composition, characterized in that: Contains at least one compound having the molecular structure described in claim 1.

4. The method for preparing the ether epoxy toughening agent according to claim 1, characterized in that: The method comprises the following steps: mixing polyetheramine and monocarboxylic acid containing a rigid group in a molar ratio of (1-1.1):1, adding a catalyst accounting for 0.5 wt.%-1 wt.% of the total mass of the reactants, and reacting at 150-180° C. for 4-6 hours to obtain an ether epoxy toughening agent.

5. The method for preparing the ether epoxy toughening agent according to claim 4, wherein: The monocarboxylic acid containing a rigid group is benzoic acid, o-hydroxybenzoic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, 3-hydroxy-5-methylbenzoic acid, 2-(hydroxymethyl)benzoic acid, 3-hydroxymethylbenzoic acid, 4-hydroxy-2-methylbenzoic acid, 4-hydroxy-3-methylbenzoic acid, 5-hydroxy-2-methylbenzoic acid, 3-hydroxy-2-methylbenzoic acid, 4-hydroxymethylbenzoic acid, 2-hydroxy-6-methylbenzoic acid, 2,3-dihydroxybenzoic acid, benzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, 3,5-dihydroxy-4-methylbenzoic acid, 2,3,4-trihydroxybenzoic acid, 2,3,5-trihydroxybenzoic acid, 2,3,6-trihydroxybenzoic acid, 2,4,5-trihydroxybenzoic acid, 2,4,6-trihydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid.

6. The method for preparing the ether epoxy toughening agent according to claim 4, wherein: The polyetheramine is polyetheramine D230, polyetheramine D400 or polyetheramine D2000.

7. The method for preparing the ether epoxy toughening agent according to claim 4, wherein: The molar ratio of the polyetheramine to the monocarboxylic acid containing a rigid group is 1:

1.

8. The method for preparing the ether epoxy toughening agent according to claim 4, wherein: The catalyst is one of sodium hypophosphite monohydrate, phosphoric acid or orthophosphoric acid.

9. Use of the ether epoxy toughening agent according to claim 1 in the preparation of epoxy resin.

10. The use according to claim 9, characterized in that The prepared ether epoxy toughening agent is mixed with liquid epoxy resin for reaction, and then mixed and cured with a low-temperature curing epoxy resin curing agent in equal stoichiometric ratio to obtain an ether epoxy toughening agent-modified epoxy resin material.

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