A preparation method and application of a high-toughness epoxy resin

Abstract

This application relates to the technical field of modified epoxy resins. Specifically, it relates to a high-toughness epoxy resin, its preparation method, and application, aiming to solve the problem that the epoxy resin prepared by the epoxy resin toughening and modification scheme has reduced flexibility due to poor dispersion stability. The toughened and modified epoxy resin is made from the following raw materials: 2-(but-3-enoxy)-3-hydroxypropyl acetate, maleic anhydride, polyethylene glycol, and m-chloroperoxybenzoic acid; the molar ratio of 2-(but-3-enoxy)-3-hydroxypropyl acetate to maleic anhydride is (1 to 1.1):1; the molar ratio of the first intermediate product to polyethylene glycol is (2 to 2.1):1, and the molar ratio of the second intermediate product to m-chloroperoxybenzoic acid is 1:(4 to 5); the first intermediate product is prepared by reacting 2-(but-3-enoxy)-3-hydroxypropyl acetate with maleic anhydride; the second intermediate product is prepared by reacting the first intermediate product with polyethylene glycol.

Description

Technical Field

[0001] This application relates to the technical field of modified epoxy resins. Specifically, it relates to a high-toughness epoxy resin, its preparation method, and its application. Background Art

[0002] Epoxy resins have excellent adhesive properties, mechanical properties, electrical properties, corrosion resistance, and heat resistance. They can be used as resin matrices for adhesives, coatings, and composites, etc., and are widely used in many industrial fields such as electronics, mechanical manufacturing, chemical corrosion prevention, aerospace, and biomedical materials. They have become indispensable basic materials in various industrial fields.

[0003] However, when pure epoxy resin cures, the crosslinking degree is too high, the crosslinking network skeleton is rigid, the toughness is low, and the crack resistance is poor. As a result, the cured epoxy resin coating cracks due to the accumulation of internal stress, and the cured epoxy resin coating also has disadvantages such as poor fatigue resistance and poor impact toughness. These all limit the application of epoxy resins to a certain extent. Therefore, toughening modification of epoxy resins has always been a research hotspot.

[0004] Traditional epoxy resin toughening modification schemes include rubber toughening, thermoplastic resin toughening, hyperbranched resin toughening, interpenetrating network toughening, and nano-filler toughening, etc. In these epoxy resin toughening modification processes, an additional physical blending step is required, which is prone to the problem of poor dispersion stability, which instead leads to the problem that the toughness of the toughened and modified epoxy resin is not significantly improved. Summary of the Invention

[0005] In order to solve the problem that the epoxy resin prepared by the traditional epoxy resin toughening modification scheme has poor dispersion stability, resulting in the insignificant improvement of the toughness of the toughened and modified epoxy resin, this application provides a high-toughness epoxy resin, its preparation method, and its application.

[0006] The embodiments of this application are implemented as follows:

[0007] The embodiments of this application provide a high-toughness epoxy resin. The modified epoxy resin is made from the following raw materials: 2-(but-3-enoxy)-3-hydroxypropyl acetate, maleic anhydride, polyethylene glycol, concentrated sulfuric acid, m-chloroperoxybenzoic acid, and a solvent;

[0008] Among them, the molar ratio of 2-(but-3-enoxy)-3-hydroxypropyl acetate to maleic anhydride is (1-1.1):1; the molar ratio of the first intermediate product to the polyethylene glycol is (2-2.1):1, and the molar ratio of the second intermediate product to the m-chloroperoxybenzoic acid is 1:(4-5);

[0009] Among them, the first intermediate is prepared by reacting the 2-(but-3-enyloxy)-3-hydroxypropyl acetate with maleic anhydride; the second intermediate is prepared by reacting the first intermediate with the polyethylene glycol.

[0010] In some embodiments, the molecular weight of the polyethylene glycol is 4000-8000.

[0011] The embodiment of the present application also provides a preparation method of a high-toughness epoxy resin, and the method includes:

[0012] Take 2-(but-3-enyloxy)-3-hydroxypropyl acetate and maleic anhydride, react under the first preset conditions to obtain a first intermediate, and the first intermediate is 2-(but-3-enyloxy)-3-hydroxypropyl acetate maleic monoester;

[0013] Add polyethylene glycol and concentrated sulfuric acid to the first intermediate, and carry out an esterification reaction under the second preset conditions to obtain a second intermediate;

[0014] Take the second intermediate and m-chloroperoxybenzoic acid and dissolve them in a solvent, and carry out an epoxidation reaction under the third preset conditions to obtain a high-toughness epoxy resin.

[0015] In some embodiments, when reacting under the first preset conditions, the molar ratio of the 2-(but-3-enyloxy)-3-hydroxypropyl acetate to maleic anhydride is (1-1.1):1.

[0016] In some embodiments, when reacting under the second preset conditions, the molar ratio of the first intermediate, the polyethylene glycol to the concentrated sulfuric acid is (2-2.2):1:(0.2-0.5), and the average molecular weight of the polyethylene glycol is 4000-8000.

[0017] In some embodiments, when reacting under the third preset conditions, the molar ratio of the m-chloroperoxybenzoic acid to the second intermediate is (4-5):1, and the solvent is dichloromethane.

[0018] In some embodiments, the reaction temperatures of the first preset conditions and the second preset conditions are both 90-120 °C, and the reaction times are both 3h-6h; the reaction under the third preset conditions is carried out in a water bath at a temperature of 5 °C-15 °C, and the reaction time is 8h-12h.

[0019] The embodiment of the present application also provides an application of a high-toughness epoxy resin, including the application of the high-toughness epoxy resin as described above in the fields of coatings, electronic packaging and adhesives.

[0020] Advantages of the present application: The polyethylene glycol molecular chain contains abundant rotatable C-O bonds. By modifying epoxy resin with polyethylene glycol, the flexibility of epoxy resin can be significantly improved at the molecular level, and the toughening effect is good and the performance effect is stable. Further, since polyethylene glycol also has advantages such as good water solubility, good biocompatibility, good lubricity, and good adhesiveness, the epoxy resin modified by polyethylene glycol can also be used in fields such as aerospace materials and biomedical materials with high requirements for environmental protection and biotoxicity. Further, the modified epoxy resin of the present application does not need to introduce emulsifiers or dispersants during the synthesis process, the reaction is easy to control, the synthesis process is simple, and it can be widely promoted on a large scale. Brief Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is the nuclear magnetic hydrogen spectrum diagram provided by the embodiment of the present application. Detailed Embodiments

[0023] To enable those skilled in the art to understand the features and effects of the present invention, the following will generally explain and define the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein shall have the ordinary meaning understood by those skilled in the art for the present invention. In case of conflict, the definition in this specification shall prevail.

[0024] The theories or mechanisms described and disclosed herein, whether correct or incorrect, shall not limit the scope of the present invention in any way, that is, the content of the present invention can be implemented without being limited by any specific theory or mechanism.

[0025] In this article, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).

[0026] In this article, unless otherwise specified, terms such as "comprising", "including", "containing", "having", or similar terms cover the meanings of "consisting of" and "consisting essentially of". For example, "A comprises a" covers the meanings of "A comprises a and others" and "A only comprises a".

[0027] In this document, for the sake of concise description, all possible combinations of all technical features in each implementation or embodiment are not described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation or embodiment can be combined arbitrarily, and all possible combinations should be considered as the scope described in this specification.

[0028] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0029] In the following embodiments, conventional instruments and equipment in the art are used. For the experimental methods without specific conditions noted in the following embodiments, they are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. In the following embodiments, various raw materials are used. Unless otherwise specified, commercially available products are used, and their specifications are conventional specifications in the art. In the specification of the present invention and the following embodiments, unless otherwise specified, "%" represents weight percentage, "parts" represents weight parts, and the ratio represents weight ratio.

[0030] The embodiment of the present application provides a high-toughness epoxy resin. The modified epoxy resin is made from the following raw materials: 2-(but-3-enoxy)-3-hydroxypropyl acetate, maleic anhydride, polyethylene glycol, concentrated sulfuric acid, m-chloroperoxybenzoic acid, and a solvent;

[0031] Among them, the molar amount of 2-(but-3-enoxy)-3-hydroxypropyl acetate: the molar amount of maleic anhydride = (1 to 1.1): 1; the molar amount of the first intermediate: the molar amount of the polyethylene glycol = (2 to 2.1): 1, the molar amount of the second intermediate: the molar amount of the m-chloroperoxybenzoic acid = 1: (4 to 5);

[0032] Among them, the first intermediate is prepared by reacting 2-(but-3-enoxy)-3-hydroxypropyl acetate with maleic anhydride; the second intermediate is prepared by reacting the first intermediate with the polyethylene glycol.

[0033] In some embodiments, the molecular weight of the polyethylene glycol is 4000 to 8000.

[0034] The embodiment of the present application also provides a preparation method of a high-toughness epoxy resin. The method includes the following steps:

[0035] React 2-(but-3-enyloxy)-3-hydroxypropyl acetate with maleic anhydride under the first preset conditions to obtain a first intermediate product, which is 2-(but-3-enyloxy)-3-hydroxypropyl acetate maleic monoester;

[0036] Add polyethylene glycol and concentrated sulfuric acid to the first intermediate product and carry out an esterification reaction under the second preset conditions to obtain a second intermediate product;

[0037] Take the second intermediate product and m-chloroperoxybenzoic acid, dissolve them in a solvent, and carry out an epoxidation reaction under the third preset conditions to obtain a high-toughness epoxy resin.

[0038] In some embodiments, when reacting under the first preset conditions, the molar ratio of 2-(but-3-enyloxy)-3-hydroxypropyl acetate to maleic anhydride is (1 - 1.1)∶1.

[0039] In some embodiments, when reacting under the second preset conditions, the amount of substance of the first intermediate product∶the amount of substance of the polyethylene glycol∶the amount of substance of the concentrated sulfuric acid = (2 - 2.2)∶1∶(0.2 - 0.5), and the average molecular weight of the polyethylene glycol is 4000 - 8000.

[0040] In some embodiments, when reacting under the third preset conditions, the amount of substance of m-chloroperoxybenzoic acid (i.e., mCPBA)∶the amount of substance of the second intermediate product = (4 - 5)∶1, and the solvent is dichloromethane.

[0041] In some embodiments, the reaction temperatures of the first preset conditions and the second preset conditions are both 90 - 120°C, and the reaction times are both 3h - 6h; the reaction under the third preset conditions is carried out in a water bath at a temperature of 5°C - 15°C, and the reaction time is 8h - 12h.

[0042] The embodiments of the present application also provide an application of the high-toughness epoxy resin, including the application of the high-toughness epoxy resin as described above in the fields of coatings, electronic packaging, and adhesives.

[0043] In some embodiments, the principle equation for preparing the high-toughness epoxy resin of the present application is also provided:

[0044]

[0045] Where n = 76 - 167.

[0046] The following further illustrates the present application with specific embodiments.

[0047] Example 1

[0048] Add 3 g of 2-(but-3-enyloxy)-3-hydroxypropyl acetate into a three-necked flask equipped with a rotor, a thermometer and a reflux condenser. Turn on the magnetic stirring, set the oil bath temperature at 110 °C. After preheating, add 1.6 g of maleic anhydride and react for 5 h;

[0049] Continue to add 24.4 g of polyethylene glycol and 0.1 ml of concentrated sulfuric acid and continue the esterification reaction for 2 h. After the reaction is completed, take out the product and cool it down;

[0050] Transfer the three-necked flask containing the product to an ice-water bath. When the thermometer shows a temperature of 5 - 15 °C, add 5 g of m-chloroperoxybenzoic acid and react for 10 h to obtain a polyethylene glycol-modified high-toughness epoxy resin.

[0051] Example 2

[0052] Add 3.6 g of 2-(but-3-enyloxy)-3-hydroxypropyl acetate into a three-necked flask equipped with a rotor, a thermometer and a reflux condenser. Turn on the magnetic stirring, set the oil bath temperature at 110 °C. After preheating, add 1.9 g of maleic anhydride and react for 5 h;

[0053] Continue to add 29.3 g of polyethylene glycol and 0.2 ml of concentrated sulfuric acid and continue the esterification reaction for 2 h. After the reaction is completed, take out the product and cool it down;

[0054] Transfer the three-necked flask containing the product to an ice-water bath. When the thermometer shows a temperature of 5 - 15 °C, add 6 g of m-chloroperoxybenzoic acid and react for 10 h to obtain a polyethylene glycol-modified high-toughness epoxy resin.

[0055] Example 3

[0056] Add 3.6 g of 2-(but-3-enyloxy)-3-hydroxypropyl acetate into a three-necked flask equipped with a rotor, a thermometer and a reflux condenser. Turn on the magnetic stirring, set the oil bath temperature at 110 °C. After preheating, add 1.9 g of maleic anhydride and react for 5 h;

[0057] Add 32.2 g of polyethylene glycol and 0.2 ml of concentrated sulfuric acid and continue the esterification reaction for 2 h. After the reaction is completed, take out the product and cool it down;

[0058] Transfer the three-necked flask containing the product to an ice-water bath. When the thermometer shows a temperature of 5 - 15 °C, add 6.6 g of m-chloroperoxybenzoic acid and react for 10 h to obtain a polyethylene glycol-modified high-toughness epoxy resin.

[0059] Example 4

[0060] Add 5 g of 2-(but-3-enyloxy)-3-hydroxypropyl acetate to a three-necked flask equipped with a rotor, a thermometer and a reflux condenser. Turn on the magnetic stirrer and set the oil bath temperature to 110 °C. After preheating, add 2.6 g of maleic anhydride and react for 5.5 h;

[0061] Add 40.7 g of polyethylene glycol and 0.2 mL of concentrated sulfuric acid and continue the esterification reaction for 2 h. After the reaction is completed, take out the product and cool it down;

[0062] Transfer the three-necked flask containing the product to an ice-water bath. When the thermometer shows a temperature of 5 - 15 °C, add 8.3 g of m-chloroperoxybenzoic acid and react for 10 h to obtain a polyethylene glycol-modified high-toughness epoxy resin.

[0063] Example 5

[0064] Add 7 g of 2-(but-3-enyloxy)-3-hydroxypropyl acetate to a three-necked flask equipped with a rotor, a thermometer and a reflux condenser. Turn on the magnetic stirrer and set the oil bath temperature to 110 °C. After preheating, add 3.7 g of maleic anhydride and react for 6 h;

[0065] Add 57.0 g of polyethylene glycol and 0.3 mL of concentrated sulfuric acid and continue the esterification reaction for 2 h. After the reaction is completed, take out the product and cool it down;

[0066] Transfer the three-necked flask containing the product to an ice-water bath. When the thermometer shows a temperature of 5 - 15 °C, add 11.7 g of m-chloroperoxybenzoic acid and react for 11 h to obtain a polyethylene glycol-modified high-toughness epoxy resin.

[0067] To characterize the structural features of a toughened and modified epoxy resin, the toughened and modified epoxy resin synthesized in Example 5 was subjected to a proton nuclear magnetic resonance (¹H NMR) test. The ¹H NMR spectrum is as Figure 1 shown, and the test results are as follows:

[0068] 1 ¹H NMR (300 MHz, DMSO): δ 4.48 (t, H), 4.32 (q, H), 4.07 (m, H), 3.35 (t, H), 2.60 (q, H), 2.35 (m, H), 2.04 (s, H), 1.64 (q, H) ppm.

[0069] From the NMR data, it can be seen that the present invention has successfully prepared a toughened and modified epoxy resin with the target structure.

[0070] In order to test the mechanical properties of the high-toughness epoxy resin of the present application, the epoxy resins prepared in Examples 1-5 were cured into films. Specifically: the epoxy resins prepared according to the methods described in Examples 1-5 were mixed with an epoxy curing agent, an initiator, and an active diluent in a certain proportion, stirred evenly, coated on the surface of a glass plate, and placed in an oven at 60 °C for curing for 20 min. Among them, the epoxy curing agent used was an aqueous amine curing agent (for example, an aqueous amine curing agent with the brand of Hanson and the model of EPIKURE 8545-W-52), and the mass ratio of the high-toughness epoxy resin to the epoxy curing agent was 3:1.

[0071] The mechanical property experiments were carried out using a TS2000-S universal testing machine; the impact resistance was measured according to GB / T 1732-1993 (Method for Determining the Impact Resistance of Coating Films). The test results are shown in Table 1.

[0072] Table 1 Performance test results after curing and film-forming of the high-toughness epoxy resins in Examples 1-5

[0073]

[0074] From the test results in the above table, it can be seen that the epoxy resins prepared in Examples 1-5 of the present invention have good flexibility. This is because the poly(ethylene glycol) molecular chain contains abundant rotatable C-O bonds. By modifying the epoxy resin with poly(ethylene glycol), the flexibility of the epoxy resin can be significantly improved at the molecular level, and the toughening effect is good and the performance effect is stable.

[0075] Furthermore, due to the advantages of good water solubility, good biocompatibility, good lubricity, good adhesiveness, etc. of poly(ethylene glycol), the epoxy resin modified with poly(ethylene glycol) can also be used in fields such as aerospace materials and biomedical materials with high requirements for environmental protection and biotoxicity; further, the modified epoxy resin of the present application does not need to introduce an emulsifier or a dispersant during the synthesis process, the reaction is easy to control, the synthesis process is simple, and it can be widely promoted on a large scale.

[0076] For the sake of convenience of explanation, the above description has been made in conjunction with specific embodiments. However, the above discussion in some embodiments is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. According to the above teachings, various modifications and deformations can be obtained. The selection and description of the above embodiments are for better explaining the principles and practical applications, so that those skilled in the art can better use the embodiments and various different deformed embodiments suitable for specific use considerations.

Claims

1. A high-toughness epoxy resin, characterized in that, The high-toughness epoxy resin is made from the following raw materials: 2-(but-3-enyloxy)-3-hydroxypropyl acetate, maleic anhydride, polyethylene glycol, concentrated sulfuric acid, m-chloroperoxybenzoic acid, and a solvent; Among them, the molar ratio of 2-(but-3-enyloxy)-3-hydroxypropyl acetate to maleic anhydride is (1~1.1):1; the molar ratio of the first intermediate product to the polyethylene glycol is (2~2.1):1, and the molar ratio of the second intermediate product to the m-chloroperoxybenzoic acid is 1:(4~5); Among them, the first intermediate product is prepared by reacting 2-(but-3-enyloxy)-3-hydroxypropyl acetate with maleic anhydride; the second intermediate product is prepared by reacting the first intermediate product with the polyethylene glycol; The molecular weight of the polyethylene glycol is 4000~8000.

2. A preparation method of a high-toughness epoxy resin, characterized in that, The method includes: Taking 2-(but-3-enyloxy)-3-hydroxypropyl acetate and maleic anhydride, reacting them under the first preset conditions to obtain a first intermediate product, and the first intermediate product is 2-(but-3-enyloxy)-3-hydroxypropyl acetate maleic monoester; Adding polyethylene glycol and concentrated sulfuric acid to the first intermediate product, and carrying out an esterification reaction under the second preset conditions to obtain a second intermediate product; Taking the second intermediate product and m-chloroperoxybenzoic acid, dissolving them in a solvent, and carrying out an epoxidation reaction under the third preset conditions to obtain a high-toughness epoxy resin; When reacting under the first preset conditions, the molar ratio of 2-(but-3-enyloxy)-3-hydroxypropyl acetate to maleic anhydride is (1~1.1):1; When reacting under the second preset conditions, the molar ratio of the first intermediate product, the polyethylene glycol to the concentrated sulfuric acid is (2~2.2):1:(0.2~0.5), and the average molecular weight of the polyethylene glycol is 4000~8000.

3. The preparation method of the high-toughness epoxy resin according to claim 2, wherein, When reacting under the third preset conditions, the molar ratio of m-chloroperoxybenzoic acid to the second intermediate product is (4~5):1, and the solvent is dichloromethane.

4. The preparation method of the high-toughness epoxy resin according to claim 2, characterized in that, When reacting under the first preset conditions and the second preset conditions, the reaction temperature is 90~120°C, and the reaction time is 3h~6h; the reaction under the third preset conditions is carried out in a water bath at a temperature of 5°C~15°C, and the reaction time is 8h~12h.

5. Application of a high-toughness epoxy resin, characterized in that, It includes the application of the high-toughness epoxy resin as described in claim 1 in the fields of coatings, electronic encapsulation, and adhesives.

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