Phenoxy resin toughener and its preparation and use in the toughening of bisphenol diglycidyl ether compound curing
A phenoxy resin toughening agent was prepared by ring-opening reaction of epoxy groups under mild reaction conditions with triethylamine catalyst, which solved the problems of brittleness and durability of bisphenol A diglycidyl ether compounds and achieved a high-efficiency and environmentally friendly toughening effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2023-06-25
- Publication Date
- 2026-07-03
AI Technical Summary
Existing bisphenol A diglycidyl ether compounds are brittle, have poor impact resistance and fatigue durability, and are difficult to synthesize efficiently, which limits their application in high-tech fields.
Using triethylamine as a catalyst, and controlling the reaction temperature and time, a phenoxy resin toughening agent was prepared through the ring-opening reaction of bisphenol A diglycidyl ether compounds with dicarboxylic acid compounds. This agent was then used to improve the toughness of cured bisphenol A diglycidyl ether compounds.
This study achieved efficient preparation of phenoxy resin toughening agents under mild reaction conditions, improving the toughness and impact resistance of bisphenol A diglycidyl ether compounds. It is suitable for large-scale production, reduces costs, and minimizes environmental pollution.
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Figure CN119192534B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic synthesis technology, specifically relating to a new method for preparing phenoxy resin from dicarboxylic acid and bisphenol epoxy resin and its application as a toughening agent. Background Technology
[0002] Bisphenol diglycidyl ether compounds, such as common bisphenol A diglycidyl ethers, are an important class of organic synthesis intermediates. Furthermore, due to their unique chemical structures, they have wide applications in composite materials, optoelectronic materials, new energy materials, and the preparation of fine chemicals.
[0003] Because the epoxy functional group in bisphenol A diglycidyl ether compounds is highly reactive, it readily undergoes ring-opening reactions under acidic or alkaline conditions. Typically, after ring-opening, a new hydroxyl functional group forms alongside the epoxy group. Due to variations in reaction conditions, this hydroxyl group may further attack the epoxy functional group, resulting in a ring-opening product with n>1. In the above reaction system, by adding a suitable catalyst and controlling the reaction conditions, the corresponding phenoxy resin can be prepared.
[0004] Epoxy resins, due to the large number of epoxy groups in their structure, have a high density of chemical crosslinks after curing, low molecular chain flexibility, and high internal stress. This results in relatively brittle cured products with poor impact resistance and fatigue durability, limiting their application and development in high-tech fields where durability and reliability are paramount. Therefore, it is essential to modify epoxy resins to improve their toughness while maintaining their excellent properties.
[0005] The toughening methods reported in the literature for bisphenol A diglycidyl ether compounds mainly include: (1) adding rubber elastomers, core-shell polymers, thermoplastic resins, thermotropic liquid crystal polymers and nanoparticles into epoxy resin matrix to form micro-phase separation or homogeneous structures; (2) continuously penetrating thermoplastic resins in the three-dimensional cross-linked network of epoxy resin to form an interpenetrating network structure for toughening; (3) improving the molecular compliance by adjusting the microstructure of epoxy resin, such as introducing more flexible segments in the three-dimensional cross-linked network, or introducing micro-phase separation structures to enhance the deformation synergy of molecular segments and achieve toughening.
[0006] In 2015, Professor Ren Yanyu of Dalian University of Technology published a method for "a compound toughening bisphenol A epoxy resin rebar adhesive with strong adhesion in high temperature environment and its preparation method", application number: CN201510168727.5. Although the above patent reported a new toughening method based on bisphenol A epoxy resin, its principle is still to use modified nitrile rubber as toughening agent, with an addition ratio of more than 20%.
[0007] To date, no technology has been reported on the modification and toughening of bisphenol A diglycidyl ether compounds using phenoxy resin. Furthermore, the efficient synthesis of bisphenol A-based phenoxy resin faces several challenges, including raw material quality, production safety, and product stability and purity. The synthesis technology is quite difficult, and currently only a few companies in the United States, Japan, and Germany are producing it. In contrast, my country currently relies mainly on imports for some high-performance bisphenol A diglycidyl ether compound products.
[0008] To address the shortcomings of existing high-performance bisphenol A diglycidyl ether compounds, the industry is focusing on researching new methods for synthesizing corresponding bisphenol A-based phenoxy resins using stable, inexpensive, and readily available bisphenol A diglycidyl ether and dicarboxylic acid compounds as building blocks, under mild reaction conditions and with high efficiency catalysis. These methods can then be used as additives to modify and toughen bisphenol A diglycidyl ether compounds. Summary of the Invention
[0009] In view of the shortcomings of existing bisphenol A diglycidyl ether compounds, such as high brittleness, poor impact resistance and fatigue durability, the primary objective of this invention is to provide a method for preparing a phenoxy resin toughening agent, which aims to prepare a phenoxy resin-type toughening agent that can effectively improve the toughness of bisphenol A diglycidyl ether compounds.
[0010] The second objective of this invention is to provide a phenoxy resin toughening agent prepared by the aforementioned preparation method and its application as a toughening agent.
[0011] A third objective of this invention is to provide a cured substance toughened by the aforementioned phenoxy resin toughening agent.
[0012] A method for preparing a phenoxy resin toughening agent involves subjecting a bisphenol diglycidyl ether compound and a polybasic acid compound to an epoxy ring-opening reaction under the action of triethylamine.
[0013] The molar ratio of the bisphenol diglycidyl ether compound to the dicarboxylic acid compound is 1:2.0 to 4.0;
[0014] The molar ratio of triethylamine to the bisphenol diglycidyl ether compound is greater than or equal to 0.1;
[0015] The ring-opening reaction of epoxy groups takes place at temperatures above 55°C.
[0016] This invention provides a solvent-free method for synthesizing phenoxy resin. It innovatively employs triethylamine as a catalyst and, through the combined control of catalyst dosage and reaction temperature, achieves synergistic effects, effectively regulating the product structure and improving the yield and selectivity of the target structure. This facilitates the acquisition of liquid phenoxy resin products. Furthermore, research has found that the product obtained under the described preparation process and conditions can be used as a toughening agent to address the problems of high brittleness, poor impact resistance, and fatigue durability of bisphenol diglycidyl ether compounds.
[0017] In this invention, the bisphenol diglycidyl ether compound is a compound having the structural formula 1;
[0018]
[0019] In Formula 1, R1 and R2 are H, C1-C6 alkyl, C1-C6 alkoxy, halogen, nitro or trifluoromethyl;
[0020] Preferably, the bisphenol diglycidyl ether compound is a bisphenol A diglycidyl ether compound.
[0021] Preferably, the polybasic acid compound is a dicarboxylic acid compound, and a more preferred structural expression is HOOC-R-COOH, wherein R is selected from a benzene ring, a five-membered alkane ring, a six-membered alkane ring, or a C1-C10 alkylene ring;
[0022] Further preferably, the dicarboxylic acid compound is one of terephthalic acid, phthalic acid, isophthalic acid, 1,4-cyclohexyldicarboxylic acid, 1,2-cyclohexyldicarboxylic acid, 1,3-cyclohexyldicarboxylic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, and azelaic acid.
[0023] In this invention, the amount of polybasic acid compound used is not less than the theoretical reaction amount. Considering the processing cost, the molar ratio of bisphenol diglycidyl ether compound and polybasic acid compound is preferably 1:2 to 2.5.
[0024] In this invention, triethylamine was used as a catalyst to successfully prepare the phenoxy resin, improving its selectivity and yield, and enhancing the toughening effect of the prepared product on bisphenol diglycidyl ether-based resins. The study also found that further controlling the amount of triethylamine and the reaction temperature helps to synergistically improve the preparation effect and enhance the toughening effect of the prepared material on bisphenol diglycidyl ether-based resins.
[0025] Preferably, the organic amine catalyst is 0.1 to 0.3 times the molar amount of the bisphenol diglycidyl ether compound, and more preferably 0.15 to 0.25 times.
[0026] In this invention, the ring-opening reaction temperature of the epoxy group is 60–100°C, preferably 70–100°C, and more preferably 75–90°C.
[0027] In this invention, the ring-opening reaction time is more than 2 hours, preferably 3 to 15 hours, and more preferably 6 to 12 hours.
[0028] The present invention also provides a phenoxy resin toughening agent prepared by the above preparation method.
[0029] The present invention also provides an application of the phenoxy resin toughening agent prepared by the above preparation method, using it as a toughening agent.
[0030] In a preferred application of this invention, it is used as a toughening agent in the curing reaction of bisphenol diglycidyl ether compounds to prepare toughened resins.
[0031] Preferably, the bisphenol diglycidyl ether compound is the compound of Formula 1.
[0032] In a further preferred application of the present invention, a raw material comprising a bisphenol diglycidyl ether compound, a diacid precursor, a curing accelerator, and the toughening agent is subjected to a curing reaction to obtain a toughening resin.
[0033] Preferably, the diacid precursor is an acid anhydride, and more preferably methyltetrahydrophthalic anhydride;
[0034] Preferably, the weight ratio of each component in the raw material is:
[0035]
[0036] In this invention, the phenoxy resin toughening agent can be pre-composite with a bisphenol diglycidyl ether compound, and then mixed with other components for curing.
[0037] Preferably, the weight ratio of each component in the raw material is:
[0038]
[0039] The present invention also provides a toughened resin obtained by the application described herein.
[0040] Compared with the prior art, the present invention has the following beneficial effects:
[0041] (1) The preparation method of the phenoxy resin toughening agent of the present invention is simple and easy to implement, with mild reaction conditions, easy process control, and safety and reliability. The substrate has wide applicability, does not require the addition of additional organic solvents, has high atom economy, and does not cause environmental pollution. The reaction efficiency is high, the yield is high, the selectivity is good, the reaction time is short, the impurities are few, the cost is low, it is suitable for large-scale production, and has good industrial application prospects.
[0042] (2) The innovative use of the prepared phenoxy resin toughening agent as a toughening component in the cured product of bisphenol A diglycidyl ether compound can solve the defects of high brittleness, poor impact resistance and fatigue durability of the cured product. Attached Figure Description
[0043] Figure 1 The 1H-NMR spectrum of the phenoxy resin prepared from TEA as an organic amine in Example 1 is shown.
[0044] Figure 2 C-NMR spectrum of phenoxy resin prepared from TEA as an organic amine in Example 1; Detailed Implementation
[0045] In the following examples, the molar amount of organic base added refers to the molar percentage relative to bisphenol A diglycidyl ether.
[0046] In this invention, the bisphenol diglycidyl ether compound can be any bisphenol type diglycidyl ether known in the industry. In the following examples, the bisphenol diglycidyl ether compound is typically bisphenol A diglycidyl ether:
[0047] The present invention discloses a typical method for preparing bisphenol A-based phenoxy resin, which involves mixing bisphenol A diglycidyl ether with a diacid carboxylic acid compound and carrying out an epoxy ring-opening reaction under the action of an organic amine catalyst to obtain the resin.
[0048] The structural formula of the dicarboxylic acid compound is HOOC-R-COOH, where R is selected from one of phenylenediyl, cyclohexyl, methylene, ethylene, propylene, butylene, pentylene, hexylene, and heptylene. The reaction formula of the bisphenol A diglycidyl ether with the dicarboxylic acid compound using a catalyst (organic amine catalyst) is shown in equation (1) below.
[0049]
[0050] The dicarboxylic acid compound is one of terephthalic acid, phthalic acid, isophthalic acid, 1,4-cyclohexyldicarboxylic acid, 1,2-cyclohexyldicarboxylic acid, 1,3-cyclohexyldicarboxylic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, and azelaic acid.
[0051] The organic amine catalyst is at least one selected from triethylamine, 1,8-diazabicycloundec-7-ene, N,N-dimethylaniline, N,N-diethylaniline, N,N-dimethylbenzylaniline, N,N-dibenzylaniline, diisopropylethylamine, N-phenylpiperidine, and N-ethyl-N-benzylaniline. Preferred organic amine catalysts not only enable the epoxy ring-opening reaction between bisphenol A diglycidyl ether and dicarboxylic acid compounds to proceed at lower temperatures, but also exhibit high conversion and high selectivity, while avoiding the use of solvents.
[0052] The molar ratio of the bisphenol A diglycidyl ether compound to the dicarboxylic acid compound is 1:2.0 to 4.0.
[0053] The molar ratio of the bisphenol A diglycidyl ether compound to the organic amine catalyst is 1:0.05–0.3. If the proportion of organic amine used is too low, below 5% of bisphenol A diglycidyl ether, the selectivity of the reaction and the yield of the target product will be significantly reduced. When the organic amine content is increased to 20% of bisphenol A diglycidyl ether, the yield and selectivity of the target product reach the optimal level. Further increasing the organic amine content will result in a slight decrease in the yield and selectivity of the target product. Therefore, the molar ratio of bisphenol A diglycidyl ether to the organic amine catalyst is further preferably 1:0.1–0.3.
[0054] The ring-opening reaction conditions are as follows: under nitrogen protection, the reaction temperature is 55–100°C, and the reaction time is 3–15 h. A further preferred reaction temperature is 60–100°C, and the most preferred temperature is 70–90°C. Within the preferred temperature and time range, appropriately increasing the reaction temperature and extending the reaction time is beneficial for increasing the yield of the target product; however, excessively high reaction temperatures and times will increase the impact of side reactions.
[0055] A typical toughening step of the present invention is as follows: the obtained phenoxy resin is added to the bisphenol A diglycidyl ether compound by mass ratio and mixed evenly. The mass ratio of the bisphenol A diglycidyl ether compound to the phenoxy resin is 1:0.001 to 0.1, and more preferably 1:0.001 to 0.05.
[0056] In the following cases, the tensile strength, flexural strength, and impact tests were all conducted using industry-standard tests, such as the national standard GB / T 9341-2008 / ISO 178:2001.
[0057] In this invention, in the following examples, the product selectivity refers to the proportion in which carboxyl groups selectively attack the epoxy groups in bisphenol A diglycidyl ether to form an ordered polyester compound.
[0058] In the following cases, the molar percentage of added triethylamine refers to the molar amount of bisphenol A diglycidyl ether.
[0059] Example 1
[0060] A series of parallel reactions were prepared. 340 mg (1 mmol) of bisphenol A diglycidyl ether and 320 mg (2 mmol) of pimelic acid were added to Schlenk tubes under nitrogen protection. Then, 20 mol% of an organic base (triethylamine, 1,8-diazabicycloundec-7-ene, N,N-dimethylaniline, N,N-diethylaniline, N,N-dimethylbenzylamine, N,N-dibenzylaniline, diisopropylethylamine, N-phenylpiperidine, N-ethyl-N-benzylaniline) was added to each Schlenk tube, and the mixture was stirred at 80 °C for 6 hours to obtain pimelic acid-modified phenoxy resin. Analysis by high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) showed that the highest yield and selectivity of the target product were achieved when triethylamine was used as the base, with a selectivity of 96% and a yield of 93%. Other amines showed poor catalytic effects, resulting in hard cured products that could not be measured by NMR or have their selectivity calculated.
[0061] The NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ7.05(m,4H),6.80-6.65(m,4H),4.27-4.01(m,6H),3.97-3.76(m,4H),3.00( q,J=7.3Hz,1H),2.33-2.14(m,8H),1.67-1.47(m,14H),1.37-1.23(m,4H),1.16(t,J=7.3Hz,2H). 13 C NMR (101MHz, CDCl3) δ178.84,173.81,156.17,143.77,127.79,113.96,68.63,68.53,65.26,45 .00,41.73,34.06,33.88,33.83,30.98,30.96,28.38,28.33,24.50,24.46,24.41,24.35,8.41.
[0062] Example 2
[0063] A series of parallel reactions were prepared. 340 mg (1 mmol) of bisphenol A diglycidyl ether and 320 mg (2 mmol) of pimelic acid were added to Schlenk tubes under nitrogen protection. Then, triethylamine was added to each Schlenk tube in different molar ratios (0 mol%, 1 mol%, 5 mol%, 10 mol%, 15 mol%, 20 mol%, 30 mol%), and the reactions were stirred at 80 °C for 12 hours. Analysis by high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) showed that the highest yield and selectivity of the target product were achieved when the triethylamine addition was 20 mol%, with a selectivity of 97% and a yield of 94%. The specific data for parallel experiments with different molar ratios of triethylamine are as follows: 0 mol% (selectivity 60%, yield 3%), 1 mol% (selectivity 85%, yield 22%), 5 mol% (selectivity 88%, yield 56%), 10 mol% (selectivity 93%, yield 87%), 20 mol% (selectivity 96%, yield 93%), and 30 mol% (selectivity 92%, yield 85%).
[0064] Example 3
[0065] A series of parallel reactions were prepared. 340 mg (1 mmol) of bisphenol A diglycidyl ether and 320 mg (2 mmol) of pimelic acid were added to Schlenk tubes under nitrogen protection. Then, 20 mol% triethylamine was added to each Schlenk tube. The reactions were carried out at 25℃, 40℃, 60℃, 80℃, and 100℃ with stirring for 12 hours each, yielding pimelic acid-modified phenoxy resin. Analysis by high-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) showed the following results: (25℃, selectivity 98%, yield 5%; 40℃, selectivity 98%, yield 22%; 60℃, selectivity 97%, yield 75%; 100℃, selectivity 91%, yield 88%).
[0066] Example 4
[0067] Compared with the TEA experimental group in Example 1, the only difference is that sebacic acid or malonic acid is used instead of pimelic acid, and all other operations and parameters are the same as in Example 1.
[0068] The experimental results were as follows: the product selectivity of the sebacic acid-modified phenoxy resin group was 97%, and the yield was 90%.
[0069] The product selectivity of the malonic acid-modified phenoxy resin group was 95%, and the yield was 91%.
[0070] Curing experiment operation steps:
[0071] Formulation: Bisphenol A diglycidyl ether (100 parts) + methyltetrahydrophthalic anhydride (88 parts) + curing accelerator (2 parts) + toughening agent (X parts); a mixture of bisphenol A phenyl oxy resin and bisphenol A diglycidyl ether is used as the toughening agent;
[0072] The curing accelerators mentioned are all well-known ingredients in the industry. For example, in the following cases, unless otherwise stated, they all refer to N,N-dimethylbenzylamine.
[0073] After adding the ingredients according to the formula, stir until well mixed. Then, place the mixture in a defoaming tank for 20-30 minutes to defoam until no visible bubbles remain. After defoaming, pour the mixture into a preheated mold sprayed with release agent, and place the mold in an oven. Cure at 100℃ for 1 hour, then increase the temperature to 140℃ and cure for another 3 hours.
[0074] Comparative Example 1
[0075] Prepare a curing mold. Cure 100g of bisphenol A diglycidyl ether, 88g of methyltetrahydrophthalic anhydride, and 2g of curing accelerator according to the above procedure. After obtaining the cured model, perform mechanical property tests. The data are as follows: tensile strength 77.86MPa, flexural strength 124.37MPa, impact test result 27.52KJ / m. 2 The experimental data obtained are from a blank control experiment.
[0076] Application Example 1
[0077] Prepare a curing mold. 100g of bisphenol A diglycidyl ether, 88g of methyltetrahydrophthalic anhydride, 2g of curing accelerator, and 10g of toughening agent (pimetriic acid-modified phenoxy resin (Example 3, 80℃ conditions): bisphenol A diglycidyl ether mass ratio = 1:1) are cured according to the above procedure. After obtaining the cured model, mechanical property tests are performed. The data are as follows: tensile strength 76.13MPa, flexural strength 77.85MPa, impact test result 33.35KJ / m. 2 .
[0078] Application Example 2
[0079] Prepare a curing mold. 100g of bisphenol A diglycidyl ether, 88g of methyltetrahydrophthalic anhydride, 2g of curing accelerator, and 10g of toughening agent (pimetriic acid-modified phenoxy resin (Example 3, 80℃ conditions): bisphenol A diglycidyl ether mass ratio = 9:1) are cured according to the above procedure. After obtaining the cured model, mechanical property tests are performed. The data are as follows: tensile strength 80.58MPa, flexural strength 129.97MPa, impact test result 33.95KJ / m. 2 .
[0080] Application Example 3
[0081] Prepare a curing mold. 100g of bisphenol A diglycidyl ether, 88g of methyltetrahydrophthalic anhydride, 2g of curing accelerator, and 5g of toughening agent (pimetriic acid-modified phenoxy resin (Example 3, 80℃ conditions): bisphenol A diglycidyl ether mass ratio = 1:9) are cured according to the above procedure. After obtaining the cured model, mechanical property tests are performed. The data are as follows: tensile strength 84.61MPa, flexural strength 151.46MPa, and impact resistance 36.2KJ / m. 2 .
[0082] Application Example 4
[0083] Prepare a curing mold. Add 100g of bisphenol A diglycidyl ether, 88g of methyltetrahydrophthalic anhydride, 2g of curing accelerator, and 5g of toughening agent (sebacic acid-modified phenoxy resin:bisphenol A diglycidyl ether mass ratio = 1:9) to the mold according to the above procedure. After obtaining the cured mold, perform mechanical property tests. The data are as follows: tensile strength 79.61MPa, flexural strength 139.05MPa, and impact resistance 33.1KJ / m. 2 .
[0084] Application Example 5
[0085] Prepare a curing mold. Add 100g of bisphenol A diglycidyl ether, 88g of methyltetrahydrophthalic anhydride, 2g of curing accelerator, and 10g of toughening agent (malonic acid modified phenoxy resin:bisphenol A diglycidyl ether mass ratio = 1:9) to the mold according to the above procedure. After obtaining the cured mold, perform mechanical property tests. The data are as follows: tensile strength 84.11MPa, flexural strength 145.84MPa, and impact resistance 33.7KJ / m. 2 .
[0086] As can be seen from the above embodiments, the method employed in this invention, which utilizes the efficient reaction of bisphenol A diglycidyl ether with dicarboxylic acid compounds to prepare the corresponding phenoxy resin, and then selectively toughens it by proportioning it with bisphenol A diglycidyl ether, has advantages such as mild reaction conditions, inexpensive and readily available catalysts, and high regioselectivity. Furthermore, this method also has advantages such as wide substrate applicability and high yield, providing an efficient method for synthesizing bisphenol A-based phenoxy resins containing different substituted functional groups.
[0087] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.
Claims
1. A method for preparing a phenoxy resin toughening agent, characterized in that, The bisphenol diglycidyl ether compound and polybasic acid compound are subjected to an epoxy ring-opening reaction in the presence of triethylamine to obtain the product. The molar ratio of the bisphenol diglycidyl ether compound to the dicarboxylic acid compound is 1:2.0~4.0; The amount of triethylamine is 0.1 to 0.3 times the molar amount of the bisphenol diglycidyl ether compound. The ring-opening reaction of epoxy groups takes place at temperatures of 60–100 °C. Bisphenol diglycidyl ether compounds are compounds having the structural formula 1; Formula 1 In Formula 1, R1 and R2 are individually H, C1-C6 alkyl, C1-C6 alkoxy, halogen, nitro or trifluoromethyl; Polybasic acid compounds are dicarboxylic acid compounds with the structural formula HOOC-R-COOH, where R is a C1~C10 alkylene group.
2. The method for preparing the phenoxy resin toughening agent as described in claim 1, characterized in that, The bisphenol diglycidyl ether compound is a bisphenol A diglycidyl ether compound.
3. The method for preparing the phenoxy resin toughening agent as described in claim 1, characterized in that, The dicarboxylic acid compound mentioned is one of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, and azelaic acid.
4. The method for preparing the phenoxy resin toughening agent according to any one of claims 1 to 3, characterized in that, The molar ratio of bisphenol diglycidyl ether compounds and polybasic acid compounds is 1:2 to 2.
5.
5. The method for preparing the phenoxy resin toughening agent as described in claim 1, characterized in that, The amount of triethylamine is 0.15 to 0.25 times the molar amount of the bisphenol diglycidyl ether compound.
6. The method for preparing the phenoxy resin toughening agent as described in claim 1, characterized in that, The ring-opening reaction of epoxy groups takes place at a temperature of 70~100℃.
7. The method for preparing the phenoxy resin toughening agent as described in claim 6, characterized in that, The ring-opening reaction of epoxy groups takes place at temperatures of 75-90℃.
8. The method for preparing the phenoxy resin toughening agent as described in claim 1, characterized in that, The ring-opening reaction takes more than 2 hours.
9. The method for preparing the phenoxy resin toughening agent as described in claim 8, characterized in that, The ring-opening reaction takes 3 to 15 hours.
10. A phenoxy resin toughening agent prepared by the preparation method according to any one of claims 1 to 9.
11. The application of a phenoxy resin toughening agent prepared by the preparation method according to any one of claims 1 to 9, characterized in that, As a toughening agent.
12. The application as described in claim 11, characterized in that, It was used as a toughening agent in the curing reaction of bisphenol diglycidyl ether compounds to prepare toughened resin.
13. The application as described in claim 11 or 12, characterized in that, A toughening resin is prepared by subjecting a raw material containing a bisphenol diglycidyl ether compound, a diacid precursor, a curing accelerator, and the toughening agent to a curing reaction.
14. The application as described in claim 13, characterized in that, The aforementioned diacid precursor is an acid anhydride.
15. The application as described in claim 14, characterized in that, The diacid precursor is methyltetrahydrophthalic anhydride.
16. The application as described in claim 14, characterized in that, The weight ratio of each component in the raw material is as follows: 100 parts of bisphenol diglycidyl ether compound; 80-90 parts of diacid precursor; 1-5 parts of curing accelerator; The toughening agent is 0.001 to 10 parts.
17. A toughened resin obtained by any one of claims 11 to 16.