Preparation method of high-toughness epoxy resin sizing material

Abstract

The invention provides a high-toughness epoxy resin sizing material and a preparation method thereof. The sizing material comprises the following components: 100 parts of epoxy resin, 10-20 parts of a modified toughening agent, 5-20 parts of a modified curing agent, 10-20 parts of a diluent and 0.1-4 parts of an accelerant, the modified toughening agent is obtained by sequentially carrying out graft modification on the toughening agent by diisocyanate and an alcohol substance; the modified curing agent is obtained by modifying the curing agent through Mannich reaction of long-chain phenol and formaldehyde or paraformaldehyde; the modified curing agent and the modified toughening agent are connected through chemical bonds, so that a load absorption-transfer-resistance synergistic mechanism can be further formed, and the toughness and tensile strength of the epoxy resin are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high molecular material synthesis, and in particular to a high-toughness epoxy resin sizing material and a preparation method thereof. BACKGROUND

[0002] Epoxy resin is a widely used thermosetting resin, which has the characteristics of strong bonding force, high heat resistance, good stability and small shrinkage, and is widely used in the fields of electronics, transportation and aerospace. Amine curing agent is the most commonly used curing agent for epoxy resin, which can be divided into aliphatic amines, aromatic amines and amine derivatives, etc. It has the advantages of fast curing speed, low viscosity and convenient use, and is widely used in the crosslinking and curing of epoxy resin. Generally speaking, the curing time of aliphatic amines, alicyclic amines, amides and aromatic amines gradually increases, and the curing reaction activity of primary amines, secondary amines and tertiary amines gradually decreases. Aliphatic primary amine curing agent can be cured and crosslinked with epoxy resin at room temperature.

[0003] Pure epoxy resin has high crosslinking density after curing, which results in high internal stress, brittleness and low fracture toughness, etc., limiting its application under high load and strong impact conditions, so it is necessary to modify the epoxy resin. There are still some problems in the modification process, mainly reflected in the difficulty in balancing the comprehensive performance. For example: the rubber toughening effect is obvious, but the strength and heat resistance of the epoxy resin system after toughening are significantly reduced, and the system viscosity is high. The compatibility of thermoplastic resin with epoxy resin is poor, and the strength of the system decreases after toughening. The heat resistance of the system decreases after toughening by hyperbranched polymer, and the complex synthesis process leads to high cost. The heat-induced liquid crystal polymer is limited by the curing agent, and also has the problem of high cost. The preparation technology of core-shell particles has high threshold, and the heat resistance of the system decreases after toughening. Inorganic nanoparticles can improve the toughness, strength and heat resistance of epoxy resin at the same time, but there are problems such as poor compatibility with epoxy resin and easy agglomeration of particles.

[0004] CN106085325A provides a tertiary amine modified liquid nitrile rubber toughened epoxy adhesive, which uses tertiary amine to modify liquid nitrile rubber, significantly improves the impact strength, elongation at break and glass transition temperature of the epoxy resin, but the tensile strength decreases significantly. Therefore, how to improve the toughness of the epoxy resin without reducing the tensile strength is a problem to be solved at present. SUMMARY

[0005] In order to solve the above problems, the present application provides a high-toughness epoxy resin sizing material, which comprises the following components in parts by weight: epoxy resin 100 parts, modified toughening agent 10-20 parts, modified curing agent 5-20 parts, diluent 10-20 parts and accelerator 0.1-4 parts. The modified toughening agent is obtained by grafting modification of the toughening agent with diisocyanate and alcohol in sequence; the toughening agent comprises at least one of carboxyl liquid butyl nitrile rubber, hydroxyl liquid butyl nitrile rubber or mercapto liquid butyl nitrile rubber. The modified curing agent is obtained by Mannich reaction of long-chain phenol and formaldehyde or polyformaldehyde on the curing agent; the curing agent is an amine curing agent.

[0006] Further, the amine curing agent comprises at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethylene polyamine or trimethyl hexanediamine.

[0007] Further, the toughening agent is carboxyl-terminated liquid butyl nitrile rubber with a functionality of 2.

[0008] Further, the accelerator comprises at least one of 2,4,6-tris(dimethylaminomethyl)phenol DMP-30, dimethylbenzylamine, salicylic acid, triethylamine, triethanolamine, m-dihydroxybenzene or 1,8-diazabicyclo-5,4,0)-7-undecene; Further, the diluent comprises at least one of ethyl acetate, butyl acetate, acetone, butanone, dibutyl phthalate, toluene, anhydrous ethanol or neopentyl glycol diglycidyl ether.

[0009] Further, the diisocyanate comprises at least one of hexamethylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate or isophorone diisocyanate. Further, the alcohol comprises at least one of PEG, 3-dimethylamino-1-propanol, octanediol or dodecanediol, preferably PEG200.

[0010] Further, the long-chain phenol comprises at least one of p-t-octylphenol, cardanol, alkyl resorcinol, 4-nonylphenol or isododecyl phenol.

[0011] Further, the preparation method of the modified toughening agent is: under the protection of inert gas, diisocyanate and catalyst are sequentially added to the toughening agent, stirred at 75-85℃ for 1.5-2.5h, then alcohol is added, heated to 90-95℃, and reacted for 2-3h to obtain the modified toughening agent. Further, the mass ratio of the toughening agent, diisocyanate and alcohol is 10: (0.8-1.5): (0.1-0.5).

[0012] Further, the preparation method of the modified curing agent is as follows: uniformly mixing the amine curing agent and long-chain phenol, heating to 70-80 DEG C, adding formaldehyde or paraformaldehyde, heating to 110-120 DEG C and refluxing for 3-5 h to obtain the modified curing agent; preferably, after heating to 110-120 DEG C, additional formaldehyde or paraformaldehyde is added again, and refluxing is carried out for 3-5 h. Further, the mass ratio of the amine curing agent, long-chain phenol and formaldehyde or paraformaldehyde is 10: (3-8) : (2-5).

[0013] The application further provides a preparation method of the high-toughness epoxy resin sizing material, comprising the following steps: preheating the epoxy resin at 50-70 DEG C for 10-20 min, sequentially adding the modified toughening agent, diluent, modified curing agent and accelerator, uniformly stirring, vacuum degassing, and curing to obtain the high-toughness epoxy resin sizing material.

[0014] Further, the curing temperature is 50-70 DEG C, and the curing time is 10-15 h.

[0015] The application has the following beneficial effects: The application introduces flexible chain segments and active groups into the curing agent and the toughening agent for modification, adds the modified curing agent and the modified toughening agent into the epoxy resin system to prepare the high-toughness epoxy resin sizing material with an interpenetrating network structure, and the toughness is improved through the sliding or deformation of the flexible chain segments, and the tensile strength is improved through the energy absorption of the rigid chain segments; further, the modified curing agent and the modified toughening agent are connected through chemical bonds, and a synergistic mechanism of load absorption-transmission-resistance can be further formed, thereby greatly improving the toughness and tensile strength of the epoxy resin. DETAILED DESCRIPTION

[0016] The embodiments of the application will be described in detail below with reference to the examples, and the following examples are only used to illustrate the application, and should not be regarded as limiting the scope of the application.

[0017] The number average molecular weight of the carboxyl-terminated liquid butyl nitrile rubber used in the following examples and comparative examples is 4000±200, and the carboxyl functionality is 2; the mass content of formaldehyde in the formaldehyde aqueous solution is 37%.

[0018] Example 1 (1) Modification of aliphatic amine curing agent Take 50g diethylene triamine and 30g of cashew phenol into a three-necked flask, place it in an oil bath, stir at 800r / min, when the oil bath is heated to 75℃, take 7.54g formaldehyde solution and add it to the three-necked flask, continue to heat at a rate of 1.5℃ / min, until the temperature is 120℃, then add 8g formaldehyde solution to the flask, and react, dropwise add at a speed of about 0.27g / min within 30min, reflux for 3h.

[0019] After the reaction is completed, vacuum dehydration is carried out, and distillation is stopped when the liquid phase temperature is 120℃ to obtain a modified diethylene triamine curing agent.

[0020] (2) Toughening agent graft modification Put 50g carboxyl-terminated liquid butadiene rubber into a three-necked flask, vacuum dehydrate at 80℃ for 1h; then introduce nitrogen, add 5.4g hexamethylene diisocyanate coupling agent to the three-necked flask, add 1 drop of catalyst dibutyltin dilaurate after dropwise addition is completed, mechanically stir at 80℃ for 2h, then add 1.1g PEG200, heat to 90℃, and react for 3h; then remove unreacted polyethylene glycol, vacuum dry to obtain modified carboxyl-terminated liquid butadiene rubber.

[0021] (3) Preparation of high-toughness epoxy resin Take 100g of bisphenol A type epoxy resin (E-51) and place it in a water bath, heat to 60℃ for 15min, add 15g of modified carboxyl-terminated liquid butadiene rubber prepared in step (2), stir for 15min, add 20g of diluent acetone to reduce the viscosity, continue to stir for 5min, take 12g of modified diethylene triamine curing agent prepared in step (1), and then add 0.6g of 2,4,6-tris(dimethylaminomethyl) phenol accelerator DMP-30, stir for 10min.

[0022] Put the mixture in a vacuum drying box for 30min until no obvious bubbles, pour into a silicone mold (the silicone mold needs to be cleaned with acetone and dried, then use methyl silicone oil as a release agent), and cure at 60℃ for 12h, after curing, remove the mold after the mold temperature drops to room temperature, to obtain an epoxy resin.

[0023] Example 2 (1) Modification of aliphatic amine curing agent Take 50g triethylene tetramine and 30g cashew phenol into a three-necked flask, place it in an oil bath, stir at 800r / min, when the oil bath is heated to 75℃, take 7.54g formaldehyde solution and add it to the three-necked flask, continue to heat at a rate of 1.5℃ / min, until the temperature is 120℃, then reflux for 4h.

[0024] After the reaction, vacuum dehydration was performed, and distillation was stopped when the liquid phase temperature was 120°C to obtain the modified triethylenetetramine curing agent.

[0025] (2) Toughening agent graft modification The same as step (2) of Example 1.

[0026] (3) Preparation of high-toughness epoxy resin 100 g of bisphenol A type epoxy resin (E-51) was weighed into a water bath, preheated to 60°C for 20 min, 15 g of modified carboxyl-terminated liquid butyronitrile rubber obtained in step (2) was added, stirred for 20 min, 15 g of diluent butanone was added to reduce the viscosity, and the stirring was continued for 10 min, 7.5 g of the curing agent modified in step (1) was weighed, and 2.15 g of N'N dimethyl benzyl amine accelerator was added, and stirred for 15 min.

[0027] The mixture was placed in a vacuum drying oven for debubbling until no obvious bubbles were observed, poured into a silicone mold (the silicone mold was cleaned with acetone and dried, and then methyl silicone oil was used as a release agent), and cured at 60°C for 12 h. After curing, the mold was removed after the mold temperature dropped to room temperature, and the epoxy resin was obtained.

[0028] Example 3 (1) Modification of aliphatic amine curing agent 50 g of ethylenediamine and 17.05 g of 4-nonylphenol were weighed into a three-necked flask, placed in an oil bath, and stirred at a speed of 800 r / min. When the oil bath was heated to 75°C, 4 g of formaldehyde aqueous solution was added to the three-necked flask, and the temperature was continued to rise at a rate of 1.5°C / min until the temperature reached 120°C. Then 7.3 g of formaldehyde aqueous solution was added dropwise to the flask, and the reaction was carried out at a speed of about 0.27 g / min within 30 min. The reflux reaction was carried out for 3 h. After the reaction, vacuum dehydration was performed, and distillation was stopped when the liquid phase temperature was 125°C to obtain the modified curing agent.

[0029] (2) Toughening agent graft modification The same as step (2) of Example 1.

[0030] (3) Preparation of high-toughness epoxy resin Take 100 g of bisphenol A type epoxy resin (E-51) and place it in a water bath, preheat to 60℃ for 15 min, add 15 g of modified carboxyl-terminated liquid butyl nitrile rubber obtained in step (1), stir for 15 min, add 10 g of diluent anhydrous ethanol to reduce the viscosity, continue to stir for 15 min, take 15 g of modified curing agent obtained in step (1), and then add 3.45 g of salicylic acid accelerator, stir for 10 min until the salicylic acid is completely dissolved.

[0031] Place the mixture in a vacuum drying oven for debubbling until no obvious bubbles are present, pour into a silicone mold (the silicone mold needs to be cleaned with acetone and then dried, and then methyl silicone oil is used as a release agent), and cure at 60℃ for 12 h. After curing is completed, demold after the mold temperature drops to room temperature to obtain an epoxy resin.

[0032] Example 4 (1) Modification of aliphatic amine curing agent The same as step (1) of Example 1.

[0033] (2) Toughening agent graft modification Add 50 g of carboxyl-terminated liquid butyl nitrile rubber to a three-necked flask, vacuum dehydrate at 80℃ for 1 h; then introduce nitrogen, add 5.4 g of hexamethylene diisocyanate coupling agent to the three-necked flask, add 1 drop of catalyst dibutyltin dilaurate after dropwise addition is completed, mechanically stir at 80℃ for 2 h, then add 1.1 g of 3-dimethylamino-1-propanol, warm up to 90℃, and react for 3 h; then remove the unreacted 3-dimethylamino-1-propanol, and vacuum dry to obtain modified carboxyl-terminated liquid butyl nitrile rubber.

[0034] (3) Preparation of high-toughness epoxy resin Take 100 g of bisphenol A type epoxy resin (E-51) and place it in a water bath, preheat to 60℃ for 15 min, add 15 g of modified carboxyl-terminated liquid butyl nitrile rubber, stir for 15 min, add 20 g of diluent acetone to reduce the viscosity, continue to stir for 5 min, take 10 g of modified diethylenetriamine curing agent, and then add 0.6 g of 2,4,6-tris(dimethylaminomethyl)phenol accelerator DMP-30, and stir for 10 min.

[0035] Place the mixture in a vacuum drying oven for debubbling for 30 min until no obvious bubbles are present, pour into a silicone mold (the silicone mold needs to be cleaned with acetone and then dried, and then methyl silicone oil is used as a release agent), and cure at 60℃ for 12 h. After curing is completed, demold after the mold temperature drops to room temperature to obtain an epoxy resin.

[0036] Example 5 Different from example 1, the amount of diethylenetriamine in step (1) is 40 g, and the rest is the same as example 1.

[0037] Example 6 (1) Modification of aliphatic amine curing agent 50 g of diethylenetriamine and 30 g of cardanol were weighed into a three-necked flask, which was placed in an oil bath and stirred at a speed of 800 r / min. When the oil bath was heated to 75℃, 7.54 g of formaldehyde aqueous solution was added to the three-necked flask. After stirring for 30 min, 8 g of formaldehyde aqueous solution was added dropwise to the flask for reaction, and refluxed for 3 h.

[0038] After the reaction was completed, vacuum dehydration was performed, and distillation was stopped when the liquid phase temperature reached 120℃ to obtain the modified diethylenetriamine curing agent.

[0039] (2) Toughening agent graft modification The same as step (2) of example 1.

[0040] (3) Preparation of high-toughness epoxy resin The same as step (3) of example 1 to obtain the epoxy resin.

[0041] Comparative Example 1 Different from example 1, the toughening agent modification in step (2) of example 1 was cancelled.

[0042] (1) Modification of aliphatic amine curing agent The same as step (1) of example 1.

[0043] (2) Preparation of high-toughness epoxy resin 100 g of bisphenol A type epoxy resin (E-51) was weighed into a water bath and preheated to 60℃ for 15 min. 15 g of carboxyl-terminated liquid nitrile rubber was added and stirred for 15 min. 20 g of diluent acetone was added to reduce the viscosity, and the stirring was continued for 5 min. 12 g of modified diethylenetriamine curing agent obtained in step (1) was added, and 0.6 g of 2,4,6-tris(dimethylaminomethyl) phenol accelerator DMP-30 was added, and stirred for 10 min.

[0044] The mixture was placed in a vacuum drying oven for 30 min until no obvious bubbles were observed. It was poured into a silicone mold (the silicone mold was cleaned with acetone and dried, and then methyl silicone oil was used as a release agent). The mold was cured at 60℃ for 12 h. After the mold temperature dropped to room temperature, the mold was demolded to obtain the epoxy resin.

[0045] Comparative Example 2 Different from example 1, the curing agent modification in step (1) of example 1 was cancelled.

[0046] (1) Toughening agent graft modification The procedure of step (2) of Example 1 was followed.

[0047] (2) Preparation of high-toughness epoxy resin 100 g of bisphenol A type epoxy resin (E-51) was weighed into a water bath, heated to 60°C for 15 min, 15 g of modified carboxyl liquid butyl nitrile rubber was added, stirred for 15 min, 20 g of diluent acetone was added to reduce the viscosity, and stirring was continued for 5 min, 10 g of diethylenetriamine curing agent was added, and 0.6 g of 2,4,6-tris(dimethylaminomethyl) phenol accelerator DMP-30 was added, and stirring was continued for 10 min.

[0048] The mixture was placed in a vacuum drying oven for 30 min to remove bubbles until no obvious bubbles were observed, poured into a silicone mold (the silicone mold was cleaned with acetone and then dried, and methyl silicone oil was used as a release agent), and cured at 60°C for 12 h. After curing, the mold was removed after the temperature dropped to room temperature, and an epoxy resin was obtained.

[0049] Comparative Example 3 100 g of bisphenol A type epoxy resin (E-51) was weighed into a water bath, heated to 60°C for 15 min, 15 g of toughening agent carboxyl-terminated liquid butyl nitrile rubber was added, stirred for 15 min, 20 g of diluent acetone was added to reduce the viscosity, and stirring was continued for 5 min, 10 g of diethylenetriamine was added, and 0.6 g of DMP-30 accelerator was added, and stirring was continued for 10 min.

[0050] The mixture was placed in a vacuum drying oven for 30 min to remove bubbles until no obvious bubbles were observed, poured into a silicone mold (the silicone mold was cleaned with acetone and then dried, and methyl silicone oil was used as a release agent), and cured at 60°C for 12 h. After curing, the mold was removed after the temperature dropped to room temperature, and an epoxy resin was obtained.

[0051] The epoxy resins prepared in the above examples and comparative examples were subjected to mechanical property tests, and the test results are shown in Table 1.

[0052] ‌Impact strength test standard: GB / T 1843-2008; flexural strength test standard: GB / T 9341-2008; tensile strength test standard: GB / T 1040.1-2018.

[0053] Table 1

[0054] The present application is in the preparation of modified curing agent, formaldehyde is added twice at different temperatures, the purpose is mainly to realize the full methylation of amine, and generate a specific structure of mannich base curing agent, while overcoming the problem of high water content brought by formaldehyde aqueous solution. Taking example 1 as an example, the specific reaction process is as follows: First step: initial reaction at 75℃ (pre-condensation) At 75℃, the primary amine group of diethylenetriamine will undergo nucleophilic addition reaction with formaldehyde to generate methylol amine. This is a reversible, mild reaction stage. This stage is mainly to prepare for the further reaction under high temperature conditions in the second step.

[0055] Second step: temperature rise to 120℃ and additional formaldehyde (further mannich reaction and dehydration) Raising the temperature to 120℃ greatly improves the reaction rate, enabling the benzene ring of long-chain phenol to effectively react with the methylol amine generated in the first step (or directly with amine and formaldehyde) to generate mannich base. The formaldehyde aqueous solution introduces a large amount of water, and the mannich reaction is a reversible reaction, the byproduct water will inhibit the forward reaction, resulting in low conversion rate. Therefore, by raising the temperature to 120℃ (much higher than the boiling point of water 100℃) and reacting in a reflux device, the water generated by the reaction and the water brought in by the formaldehyde aqueous solution can be continuously azeotropically distilled out, breaking the reaction equilibrium, and the system reaction proceeds in the direction of generating mannich base, thereby significantly improving the conversion rate and molecular weight of the product.

[0056] During the modification of the curing agent, the initially added formaldehyde is mainly used to generate methylol amine with excess amine curing agent; after heating, the additional formaldehyde can further promote the mannich reaction of long-chain phenol.

[0057] During the modification of the curing agent, excess amine curing agent is used, which has the following advantages: Cashew phenol has three reactive sites, and formaldehyde and diethylenetriamine also have multiple reactive sites. Insufficient amount of amine can easily cause crosslinking reaction, and gel phenomenon can easily occur during the reaction, leading to experimental failure. Excess amine acts as a diluent and chain terminator, ensuring that the main direction of the reaction is to generate linear or branched oligomers, rather than a three-dimensional network structure, thereby obtaining a liquid curing agent with moderate viscosity and stable storage. The free diethylenetriamine part ensures that the curing agent has high reactivity and crosslinking density, so that the epoxy resin can be quickly cured and high hardness and high chemical resistance of the cured product can be obtained; while the cashew phenol mannich base part improves the compatibility with the resin, reduces the hygroscopicity of the curing agent, and reduces the brittleness of the cured product.

[0058] As can be seen from the data in Table 1, in the epoxy resin system, after adding the modified amine curing agent and the modified carboxyl liquid butyl nitrile rubber, the toughness of the epoxy resin is significantly improved. The long-chain alkyl of the phenolic substance such as cashew phenol can be inserted into the crosslinking network of the epoxy resin to reduce the internal stress and improve the toughness to a certain extent; at the same time, the aromatic ring structure enhances the rigidity of the crosslinking point, and the tensile strength of the cured product is improved. The toughening agent is modified by using diisocyanate and alcohol, the carboxyl group of the carboxyl liquid butyl nitrile rubber is first reacted with the isocyanate group to form a prepolymer containing terminal -NCO, and then reacted with the hydroxyl group of the alcohol; when PEG is selected as the alcohol substance, the polarity of PEG is more matched with that of the epoxy resin, which can make the flexible segment of the modified toughening agent more evenly dispersed, and then it is more conducive to the flexible segment to absorb the impact energy from the outside through chain segment slipping, deformation and other ways.

[0059] As can be further seen from the data of Example 1 and Comparative Examples 1-3, the modified amine curing agent and the modified carboxyl liquid butyl nitrile rubber added together in the epoxy resin system will produce a synergistic effect, because the phenolic hydroxyl group in the modified curing agent and the residual isocyanate group in the modified toughening agent will further react in the epoxy resin matrix to form -Ar-O-CO-NH-, the modified curing agent and the modified toughening agent are connected through a chemical bond, realizing the interpenetration and interconnection of the crosslinking network. The rigid skeleton of the modified curing agent provides strength, and the flexible segment of the modified toughening agent provides toughness, and the two form a continuous network of rigidity + flexibility, which is beneficial to the absorption and transmission of stress. Specifically, when the impact load acts on the epoxy resin, the flexible segment of the modified toughening agent first absorbs energy through chain segment stretching to avoid instantaneous fracture, and at the same time transmits the remaining stress to the rigid skeleton of the modified curing agent through the -Ar-O-CO-NH- chemical bond to avoid local excessive deformation; when the bending / tensile load acts on the epoxy resin, the rigid skeleton of the modified curing agent provides resistance to deformation, and the flexible segment of the modified toughening agent offsets part of the stress through elastic recovery to avoid rigid fracture, and the residual stress can be transmitted bidirectionally through the -Ar-O-CO-NH- chemical bond. Therefore, according to the reactivity of the phenolic hydroxyl group and the isocyanate group, the modified curing agent and the modified toughening agent are reasonably matched to form a synergistic mechanism of absorption-transmission-resistance, which significantly improves the mechanical properties of the epoxy resin system.

Claims

1. A high toughness epoxy resin sizing characterized in that, The epoxy resin 100 parts, the modified toughening agent 10-20 parts, the modified curing agent 5-20 parts, the diluent 10-20 parts and the accelerator 0.1-4 parts by weight; The modified toughening agent is obtained by grafting modification of the toughening agent by diisocyanate and alcohol in sequence; the toughening agent comprises at least one of carboxyl liquid butyl nitrile rubber, hydroxyl liquid butyl nitrile rubber or mercapto liquid butyl nitrile rubber; The modified curing agent is obtained by Mannich reaction of long-chain phenol and formaldehyde or paraformaldehyde on the curing agent; The curing agent is an amine curing agent.

2. A high toughness epoxy resin compound according to claim 1, characterized in that The amine curing agent comprises at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethylene polyamine or trimethyl hexanediamine.

3. The high toughness epoxy resin sizing of claim 1, wherein, The toughening agent is carboxyl-terminated liquid butyl nitrile rubber with a functionality of 2.

4. The high toughness epoxy resin compound according to claim 1, characterized in that, The accelerator comprises at least one of 2,4,6-tris(dimethylaminomethyl)phenol DMP-30, dimethylbenzylamine, salicylic acid, triethylamine, triethanolamine, resorcinol or 1,8-diazabicyclo-5,4,0)-7-undecene; The diluent comprises at least one of ethyl acetate, butyl acetate, acetone, butanone, dibutyl phthalate, toluene, anhydrous ethanol or neopentyl glycol diglycidyl ether.

5. The high toughness epoxy resin compound according to claim 1, wherein The diisocyanate comprises at least one of hexamethylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate or isophorone diisocyanate; The alcohol comprises at least one of PEG, 3-dimethylamino-1-propanol, octanediol or dodecanediol, preferably PEG200.

6. The high toughness epoxy resin compound according to claim 1, wherein The long-chain phenol comprises at least one of p-t-octylphenol, cardanol, alkyl resorcinol, 4-nonylphenol or isododecylphenol.

7. The high toughness epoxy resin compound of claim 1 wherein, The preparation method of the modified toughening agent comprises: under the protection of inert gas, diisocyanate and catalyst are sequentially added to the toughening agent, stirring at 75-85℃ for 1.5-2.5h, then alcohol is added, the temperature is raised to 90-95℃, and reaction is carried out for 2-3h to obtain the modified toughening agent; The mass ratio of the toughening agent, diisocyanate and alcohol is 10:(0.8-1.5):(0.1-0.5).

8. The high toughness epoxy resin compound of claim 1, wherein The preparation method of the modified curing agent comprises: the amine curing agent is uniformly mixed with long-chain phenol, the temperature is raised to 70-80℃, formaldehyde or paraformaldehyde is added, the temperature is raised to 110-120℃ for reflux reaction for 3-5h to obtain the modified curing agent; preferably, after the temperature is raised to 110-120℃, formaldehyde or paraformaldehyde is added again, and reflux reaction is carried out for 3-5h; The mass ratio of the amine curing agent, long-chain phenol and formaldehyde or paraformaldehyde is 10:(3-8):(2-5).

9. A process for the preparation of a high toughness epoxy resin sizing according to any one of claims 1 to 8, characterized in that, The method comprises the following steps: The epoxy resin is preheated at 50-70℃ for 10-20min, the modified toughening agent, the diluent, the modified curing agent and the accelerator are sequentially added, and the mixture is uniformly stirred and vacuum degassed to obtain high-toughness epoxy resin sizing material.

10. The method for preparing a high-toughness epoxy resin compound according to claim 9, characterized in that, The curing temperature is 50-70℃, and the curing time is 10-15h.

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