High-toughness epoxy resin composition and preparation method thereof

Abstract

The invention provides a high-toughness epoxy resin composition and a preparation method thereof. The high-toughness epoxy resin composition comprises the following raw materials in parts by mass: 100 parts of epoxy resin, 10-20 parts of a first active filler, 10-20 parts of a first active diluent, 25-40 parts of a curing agent, 5-10 parts of a second active filler and 5-10 parts of a second active diluent, wherein the first active filler is a first block polymer grafted first filler, the first block polymer comprises a first hard chain segment and a first soft chain segment, and the first block polymer comprises an epoxy group; the second active filler is a second block polymer grafted second filler, the second block polymer comprises a second hard chain segment and a second soft chain segment, and the second block polymer comprises an amino group. The high-toughness epoxy resin composition comprises the raw materials in parts by mass, and all the raw materials cooperate with one another, so that the epoxy resin composition has relatively high strength and relatively good toughness.

Description

Technical Field

[0001] This application relates to the technical field of epoxy resins, and particularly relates to a high-toughness epoxy resin composition and a preparation method thereof. Background Art

[0002] Epoxy resin materials have been widely used in fields such as aerospace, automotive manufacturing, electronic packaging, and building structures due to their excellent mechanical properties, chemical resistance, heat resistance, and outstanding adhesion. However, during the curing process, traditional epoxy resin materials form a highly cross-linked three-dimensional network structure. Although this improves the thermal stability and chemical resistance of the materials, it inevitably brings problems of relatively high brittleness and insufficient impact toughness. This inherent brittleness limits their applications under high-impact, dynamic load, and extreme environments.

[0003] To solve the problem of large brittleness of epoxy resin materials, scholars and engineering technicians at home and abroad have tried various modification methods, including introducing flexible toughening agents such as rubber, thermoplastic polymers, nanoparticles, and block copolymers, in order to improve their toughness and impact resistance while maintaining the high strength of epoxy resin materials.

[0004] The toughening agent is prone to phase separation or aggregation in the epoxy resin matrix, thus affecting the overall performance of the epoxy resin material. In addition, the compatibility between some flexible toughening agents and epoxy resins is poor, which may form microscopic defects during the curing process and reduce the strength of the final product. Moreover, it is difficult to control the curing reaction and cross-linking density. To improve toughness, it is often necessary to reduce the cross-linking density, but this may lead to a decrease in the strength of the epoxy resin material.

[0005] Patent CN119505484A discloses an epoxy resin composition and a preparation method thereof, an epoxy resin prepreg and a preparation method thereof; the steps include: mixing epoxy resin, 2,4-diphenylmethane diisocyanate, and 4,4-diphenylmethane diisocyanate and synthesizing under the action of a catalyst to obtain a transparent toughening agent; mixing the mixed epoxy resin and the transparent toughening agent to obtain a first mixed solution; adding an antifoaming agent, an ultraviolet absorber, an antioxidant, a light stabilizer, and a fluorescent agent to obtain a second mixed solution; cooling the second mixed solution to 60-70°C, adding a curing agent and an accelerator, and keeping warm and vacuumizing and defoaming and mixing for 0.3-0.4 h to obtain an epoxy resin composition. The epoxy resin composition provided by this invention has both heat resistance, high transparency, yellowing resistance, and high toughness.

[0006] Therefore, it is necessary to provide a high-toughness epoxy resin composition with relatively high strength and good flexibility. Summary of the Invention

[0007] This application provides a high-toughness epoxy resin composition and a preparation method thereof. This high-toughness epoxy resin composition can take into account relatively high strength and good toughness.

[0008] In a first aspect, the present application provides a high-toughness epoxy resin composition, which comprises the following raw materials in parts by mass: 100 parts of epoxy resin, 10 to 20 parts of a first active filler, 10 to 20 parts of a first active diluent, 25 to 40 parts of a curing agent, 5 to 10 parts of a second active filler, and 5 to 10 parts of a second active diluent; wherein, the first active filler is a first block polymer grafted with a first filler, the first block polymer comprises a first hard segment and a first soft segment, and the first block polymer has epoxy groups thereon; the second active filler is a second block polymer grafted with a second filler, the second block polymer comprises a second hard segment and a second soft segment, and the second block polymer has amino groups thereon.

[0009] According to the present application, the high-toughness epoxy resin composition comprises the above-mentioned raw materials in parts by mass. Each raw material has good reactivity, and after mixing, a network structure with a relatively high crosslinking density can be formed. At the same time, both the first active filler and the second active filler are activated and modified by block polymers, and have good compatibility with the epoxy resin system. The two aspects cooperate to make the obtained crosslinked product have a relatively high strength; at the same time, the flexible segments on the first active filler and the second active filler, in combination with the first active diluent and the second active diluent, can make the cured epoxy resin composition have good toughness; thus enabling the epoxy resin composition to have both relatively high strength and good toughness.

[0010] Specifically, the high-toughness epoxy resin composition is a product of crosslinking of epoxy resin under the action of a curing agent, and its properties are mainly determined by the types and ratios of the raw materials. Among them, the first active filler and the second active filler are respectively grafted with block polymers with active groups on their surfaces, which can effectively improve the compatibility of the filler in the epoxy resin system, promote the uniform dispersion of the filler in the system, and at the same time the active groups can participate in the crosslinking reaction and form chemical bonds with each component during the curing process to increase the crosslinking density of the crosslinked product. In addition, the rigid filler grafted with the hard segment in the block polymer in the epoxy resin crosslinked network can effectively improve the strength of the cured composition; on the other hand, using the first active diluent and the second active diluent can respectively promote the dispersion of the first active filler and the second active filler in the epoxy resin and the curing agent, making it easier for each component to be fully mixed and reacted, and making the crosslinking density of the cured epoxy resin composition more uniform; at the same time, the active diluent can also participate in the curing crosslinking reaction. The flexible segments in the active diluent cooperate with the flexible segments on the first active filler and the second active filler to provide elasticity and energy dispersion in the cured epoxy resin composition, which is beneficial to relieve stress concentration, thereby improving the toughness of the cured epoxy resin composition.

[0011] In addition, it can be understood that both the first reactive diluent and the second reactive diluent participate in the curing crosslinking reaction. Therefore, the high-toughness epoxy resin composition has no solvent volatilization, less environmental pollution, and is in line with environmentally friendly chemistry.

[0012] In some embodiments, the first rigid segment includes an epoxy group; the second flexible segment includes an amino group.

[0013] In some of the above embodiments, the epoxy group of the active group in the first active filler is grafted onto the first rigid segment, and the amino group of the active group in the second active filler is grafted onto the second flexible segment. At this time, the strength and toughness of the cured epoxy resin composition obtained are better. The reason may be that the epoxy group mainly reacts with the curing agent and the second reactive diluent in the system, and the flexibility of its segment is relatively large. If the epoxy group is grafted onto the flexible segment, it will affect the strength of the cured epoxy resin composition. At the same time, as the crosslinking site of the epoxy resin, grafting the amino group onto the flexible segment can balance the influence of the crosslinking density on the toughness. Therefore, grafting the epoxy group onto the first rigid segment and the amino group onto the second flexible segment makes the distribution of flexible segments and hard segments in the crosslinking network reasonable, and the flexible segments better compensate for the influence of the crosslinking density on the toughness, and can better balance the strength and toughness of the cured epoxy resin composition.

[0014] In some embodiments, the preparation method of the first active filler includes the following steps: S1: The first filler is subjected to silanization modification with (3-trimethoxysilyl)propyl 2-bromo-2-methylpropionate to graft a free radical reaction active group on the surface of the first filler to obtain a modified first filler; S2: The modified first filler, methyl methacrylate, and glycidyl methacrylate are subjected to a free radical polymerization reaction under catalytic conditions in an organic solvent to graft a rigid segment on the surface of the first filler to obtain a first reaction solution; S3: Butyl acrylate is added to the first reaction solution, and a free radical polymerization reaction occurs under catalytic conditions in an organic solvent to continue polymerizing and grafting a flexible segment on the rigid segment to obtain a first active filler.

[0015] In some of the above embodiments, the preparation method of the first active filler is specifically defined. The cured epoxy resin composition obtained by using the first active filler prepared by this method has better strength and toughness. Specifically, first, (3-trimethoxysilyl)propyl 2-bromo-2-methylpropionate is used to functionalize the first filler, grafting free radical active reaction groups on the surface of the first filler to provide active sites for the subsequent free radical polymerization reaction of monomers; then methyl methacrylate and glycidyl methacrylate are used together as functional monomers to carry out a free radical copolymerization reaction at the active sites on the surface of the first filler, and the copolymer of methyl methacrylate and glycidyl methacrylate is used as the hard segment on the surface of the first active filler. Poly(methyl methacrylate) has a relatively high glass transition temperature and strong rigidity, while glycidyl methacrylate can provide active epoxy groups; after the grafting of the hard segment is completed, butyl acrylate is directly added to the reaction system to carry out a free radical polymerization reaction, and poly(butyl acrylate) is grafted after the hard segment as a flexible segment. Since poly(butyl acrylate) has a long side chain and the molecular chain is more mobile, it has a low glass transition temperature and thus has good flexibility.

[0016] The first active filler obtained thus has a hard segment and a soft segment grafted thereon in sequence. The inventors found that grafting the hard segment closer to the filler side can further improve the strength and toughness of the cured epoxy resin composition; the reason may be that the high strength and structural support of the hard segment, combined with the grafted epoxy groups, can significantly improve the interfacial adhesion ability between the filler and each component in the system, so that the filler can fully exert its reinforcing effect and improve the strength of the cured epoxy resin composition. At the same time, the flexible segment grafted on the outside can further improve the dispersibility of the first active filler in the system, and it is easier to disperse the stress received by the movement of the external molecular chain, thereby improving the toughness of the cured epoxy resin composition; thus, the first active filler obtained by the above method can further improve the strength and toughness of the cured epoxy resin composition.

[0017] In some embodiments, the preparation method of the first active filler includes the following steps: S1: Disperse 20 parts of the first filler, 5 - 15 parts of (3-trimethoxysilyl)propyl 2-bromo-2-methylpropionate, and 0.1 - 2 parts of triethylamine in 500 - 1000 parts of toluene, and reflux and react at 90 - 110 °C for 18 - 24 h to obtain the modified first filler; S2: Disperse 20 parts of the modified first filler, 15 - 20 parts of methyl methacrylate, and 1 - 3 parts of glycidyl methacrylate in 150 - 300 mass parts of N,N-dimethylformamide, use 0.1 - 1 part of copper bromide and 0.1 - 1 part of pentamethyldiethylenetriamine as catalysts, and react at 80 - 90 °C under a protective atmosphere for 3 - 5 h to obtain the first reaction solution; S3: Add 15 - 20 parts of butyl acrylate to the first reaction solution, and react at 75 - 85 °C under a protective atmosphere for 3 - 5 h to obtain the first active filler.

[0018] In some of the above embodiments, the reaction conditions of each step in the preparation method of the first active filler are specifically defined. At this time, the obtained first active filler can better balance the strength and toughness of the cured epoxy resin composition. It can be understood that by controlling the ratio between the filler and each functional monomer, the lengths of the soft segment and the hard segment, as well as the number of active groups, can be controlled. Under the above conditions, a first active filler with appropriate lengths of soft segment and hard segment and good reaction activity can be grafted on the surface of the first filler, making the cured epoxy resin composition have better strength and toughness.

[0019] In some embodiments, the preparation method of the second active filler includes the following steps: M1: Use 2 - bromo - 2 - methylpropionic acid (3 - trimethoxysilyl) propyl ester to modify the second filler by silanization, grafting free - radical reaction active groups on the surface of the second filler to obtain the modified second filler; M2: Carry out a free - radical polymerization reaction between the modified second filler and methyl methacrylate under catalytic conditions in an organic solvent to graft a hard segment on the surface of the second filler to obtain a second reaction solution; M3: Add butyl acrylate and 4 - hydroxybutyl acrylate to the second reaction solution, and carry out a free - radical polymerization reaction under catalytic conditions in an organic solvent to continue polymerizing and grafting a soft segment on the hard segment to obtain a hydroxyl - containing block polymer - grafted filler; M4: Modify the hydroxyl - containing block polymer - grafted filler with an amino - silane coupling agent, so that the hydroxyl groups on the soft segment of the block polymer - grafted filler react with the amino - silane coupling agent to obtain the second active filler.

[0020] In some of the above embodiments, the preparation method of the second active filler is specifically defined. The cured epoxy resin composition obtained using this method has better strength and toughness. Specifically, first, 2 - bromo - 2 - methylpropionic acid (3 - trimethoxysilyl) propyl ester is used to graft sites for free - radical polymerization on the surface of the second filler. Then, methyl methacrylate is used as a functional monomer to polymerize to obtain poly(methyl methacrylate) as the hard segment. Subsequently, butyl acrylate and 4 - hydroxybutyl acrylate are added to the system as functional monomers to polymerize to obtain a copolymer of butyl acrylate and 4 - hydroxybutyl acrylate as the soft segment. Finally, an amino - silane coupling agent is used to react with the hydroxyl groups on the soft segment, thereby grafting active amino groups on the soft segment to obtain the second active filler.

[0021] The resulting second active filler is successively grafted with hard segments and soft segments on its surface. The soft segment containing amino groups grafted far from the second filler surface can further improve the strength and toughness of the cured epoxy resin composition. The possible reason is that the amino group, as the crosslinking site for epoxy resin curing, is grafted on one side far from the second filler surface, which can reduce the influence of steric hindrance on epoxy resin crosslinking, thereby increasing the crosslinking density of the crosslinked product. At the same time, the flexible segments on the outside are also more likely to disperse the stress received by the cured epoxy resin composition through movement, further improving the strength and toughness of the cured epoxy resin composition.

[0022] In some embodiments, the preparation method of the second active filler includes the following steps: M1: Disperse 20 parts of the second filler, 5 - 15 parts of (3 - trimethoxysilyl) propyl 2 - bromo - 2 - methylpropionate, and 0.1 - 2 parts of triethylamine in 500 - 1000 parts of toluene, and reflux and react at 90 - 110 °C for 18 - 24 h to obtain a modified second filler; M2: Disperse 20 parts of the modified second filler and 15 - 20 parts of methyl methacrylate in 150 - 300 parts by mass of N,N - dimethylformamide, use 0.1 - 1 part of cuprous bromide and 0.1 - 1 part of pentamethyldiethylenetriamine as catalysts, and react at 80 - 90 °C under a protective atmosphere for 3 - 5 h to obtain a second reaction solution; M3: Add 15 - 20 parts of butyl acrylate and 1 - 3 parts of 4 - hydroxybutyl acrylate to the second reaction solution, and react at 75 - 85 °C under a protective atmosphere for 3 - 5 h to obtain a hydroxyl - containing block polymer - grafted filler; M4: Disperse 20 parts of the hydroxyl - containing block polymer - grafted filler, 5 - 10 parts of an amino - silane coupling agent, and 0.1 - 1 part of triethylamine in 300 - 600 parts of toluene, and reflux and react at 80 - 100 °C for 3 - 8 h to obtain the second active filler.

[0023] In the above - mentioned some embodiments, the reaction conditions of each step in the preparation method of the second active filler are specifically defined. At this time, the obtained second active filler can better balance the strength and toughness of the cured epoxy resin composition. Under the above conditions, a second active filler with appropriate soft - segment and hard - segment lengths can be grafted on the surface of the second filler, and it has good reaction activity, making the cured epoxy resin composition have better strength and toughness.

[0024] In some embodiments, the protective gas is nitrogen or argon.

[0025] In some embodiments, the amino - silane coupling agent includes N - (2 - aminoethyl) - 3 - aminopropyltrimethoxysilane.

[0026] In some of the above embodiments, the inventors found that the second active filler obtained using different amino-silane coupling agents has a certain impact on the strength and toughness of the cured epoxy resin composition. When N-(2-aminoethyl)-3-aminopropyltrimethoxysilane is used as the amino-silane coupling agent, the cured epoxy resin composition can better balance strength and toughness. The possible reason is that after the reaction of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane with hydroxyl groups, in addition to a primary amine group, there is also a secondary amine group on the grafted segment of the second flexible chain segment. The secondary amine group can also participate in the curing reaction of the epoxy resin. Compared with 3-aminopropyltrimethoxysilane as the amino-silane coupling agent, it can provide more reaction sites, appropriately increase the crosslinking density, thereby further improving the strength of the cured epoxy resin composition. And the secondary amine group has only one active hydrogen and reacts with only one epoxy group. Compared with the primary amine group, the crosslinking degree of its reaction product is lower and will not significantly deteriorate the toughness of the cured epoxy resin composition. In addition, compared with diethylenetriaminepropyltrimethoxysilane, this silane coupling agent contains one primary amine group and two secondary amine groups, and the reaction sites are further increased. The further increase in crosslinking density may deteriorate the toughness of the cured epoxy resin composition. Therefore, using N-(2-aminoethyl)-3-aminopropyltrimethoxysilane can better balance the strength and toughness of the cured epoxy resin composition.

[0027] In some embodiments, the first active filler and the second active filler obtained by using the above two methods simultaneously are used. At this time, due to steric hindrance, the epoxy groups on the rigid segments of the first active filler are not easily reacted with the amino groups on the soft segments of the second active filler, enabling the active fillers to react with the epoxy resin and the curing agent respectively, making the fillers more uniformly distributed in the system, and making the cured epoxy resin composition have better strength and toughness.

[0028] In some embodiments, the first active diluent includes glycidyl ethers containing epoxy groups, and the second active diluent includes polyetheramines containing amino groups.

[0029] In some of the above embodiments, the first active diluent includes active epoxy groups, and the second active diluent includes amino groups, both of which can participate in the curing crosslinking reaction, can increase the crosslinking density, and at the same time the residual segments have good flexibility, cooperating with the flexible segments of the first active filler and the second active filler, so that the cured epoxy resin composition has better strength and toughness. As an example, in an embodiment of the present application, the first active diluent is ethylene glycol diglycidyl ether, and the second active diluent is polyetheramine 400.

[0030] In some embodiments, the epoxy resin includes at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin. As an example, in an embodiment of the present application, the epoxy resin is epoxy resin E44.

[0031] In some embodiments, the curing agent includes at least one of polyamide 300, polyamide 650, and polyamide 651. As an example, in one embodiment of the present application, the curing agent is polyamide 300.

[0032] In some embodiments, the first filler and the second filler each independently include at least one of nano calcium carbonate, nano silica, and titanium dioxide. As an example, in one embodiment of the present application, the first filler and the second filler are nano calcium carbonate with a particle size of 50 - 100 nm.

[0033] In a second aspect, the present application provides a method for preparing a high - toughness epoxy resin composition, including: Providing the raw materials of the high - toughness epoxy resin composition according to any one of the embodiments in the first aspect; mixing the epoxy resin, the first active filler, and the first active diluent to obtain a first component; mixing the curing agent, the second active filler, and the second active diluent to obtain a second component; mixing and curing the first component and the second component to obtain a high - toughness epoxy resin composition.

[0034] According to the present application, since the method includes the raw materials of the high - toughness epoxy resin composition according to any one of the embodiments in the first aspect, the high - toughness epoxy resin composition obtained by this method has the beneficial effects of the first aspect.

[0035] It can be understood that the epoxy resin containing active epoxy groups, the first active filler, and the first active diluent are mixed evenly to obtain a first component, and the curing agent containing active amino groups, the second active filler, and the second active diluent are mixed evenly to obtain a second component. When in use, the two components are mixed and cured to obtain a high - toughness epoxy resin composition.

[0036] Compared with the prior art, the beneficial effects of the present application are at least as follows: The high - toughness epoxy resin composition provided by the present application optimizes the raw material components, and the cured product can take into account both high strength and good toughness; at the same time, all raw materials can participate in the cross - linking and curing reaction, and the solvent - free formula is beneficial to reducing environmental pollution; due to its good performance, the high - toughness epoxy resin composition can be used in fields such as adhesives and coatings. Specific Embodiments

[0037] In this specification, each embodiment or implementation scheme is described in a progressive manner, and the key point of each embodiment is to illustrate the differences from other embodiments.

[0038] In the description of this specification, the descriptions with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0039] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0040] In the expressions of this specification, unless otherwise specified, "parts" all refer to "parts by mass".

[0041] Hereinafter, embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application. For those technologies or conditions not specified in the embodiments, they shall be carried out according to the technologies or conditions described in the literature in the art or according to the product specifications. For the reagents or instruments not indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0042] The CAS numbers of some reagents used in the embodiments are as follows: (3-Trimethoxysilyl)propyl 2-bromo-2-methylpropionate, CAS number is 314021-97-1; Pentamethyldiethylenetriamine, CAS number is 3030-47-5; 3-Aminopropyltriethoxysilane, CAS number is 13822-56-5; N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane, CAS number is 1760-24-3; Diethylenetriaminepropyltrimethoxysilane, CAS number is 35141-30-1.

[0043] Preparation Example 1 Ultrasonically disperse 20 parts of nano calcium carbonate in 600 parts of toluene, add 10 parts of (3-trimethoxysilyl)propyl 2-bromo-2-methylpropionate and 0.2 part of triethylamine, heat and reflux at 105 °C for 24 h, separate by centrifugation, wash with ethanol, and dry to obtain modified nano calcium carbonate; Dissolve and disperse 20 parts of modified nano calcium carbonate, 15 parts of methyl methacrylate, and 2 parts of glycidyl methacrylate in 200 parts of N,N-dimethylformamide. Remove the oxygen in the system, add 0.5 part of cuprous bromide and 0.5 part of pentamethyldiethylenetriamine, and heat and react at 90 °C for 4 h under a nitrogen atmosphere to obtain the first reaction solution; Then add 15 parts of butyl acrylate to the first reaction solution, heat and react at 85 °C for 4 h under a nitrogen atmosphere, perform centrifugal separation, wash with N,N-dimethylformamide, and dry to obtain the first active filler A (denoted as S-Y(O)-R, where S represents the filler, Y represents the hard segment, R represents the soft segment, and (O) represents the epoxy group grafted on the segment).

[0044] Preparation Example 2 Ultrasonically disperse 20 parts of nano calcium carbonate in 600 parts of toluene, add 10 parts of (3-trimethoxysilyl)propyl 2-bromo-2-methylpropionate and 0.2 part of triethylamine, heat and reflux at 105 °C for 24 h, perform centrifugal separation, wash with ethanol, and dry to obtain modified nano calcium carbonate; Dissolve and disperse 20 parts of modified nano calcium carbonate and 15 parts of butyl acrylate in 200 parts of N,N-dimethylformamide. Remove the oxygen in the system, add 0.5 part of cuprous bromide and 0.5 part of pentamethyldiethylenetriamine, and heat and react at 85 °C for 4 h under a nitrogen atmosphere to obtain the first reaction solution; Then add 15 parts of methyl methacrylate and 2 parts of glycidyl methacrylate to the first reaction solution, heat and react at 90 °C for 4 h under a nitrogen atmosphere, perform centrifugal separation, wash with N,N-dimethylformamide, and dry to obtain the first active filler B (denoted as S-R-Y(O)).

[0045] Preparation Example 3 Ultrasonically disperse 20 parts of nano calcium carbonate in 600 parts of toluene, add 10 parts of (3-trimethoxysilyl)propyl 2-bromo-2-methylpropionate and 0.2 part of triethylamine, heat and reflux at 105 °C for 24 h, perform centrifugal separation, wash with ethanol, and dry to obtain modified nano calcium carbonate; Dissolve and disperse 20 parts of modified nano calcium carbonate and 15 parts of methyl methacrylate in 200 parts of N,N-dimethylformamide. Remove the oxygen in the system, add 0.5 part of cuprous bromide and 0.5 part of pentamethyldiethylenetriamine, and heat and react at 90 °C for 4 h under a nitrogen atmosphere to obtain the first reaction solution; Then add 15 parts of butyl acrylate and 2 parts of 4-hydroxybutyl acrylate glycidyl ether to the first reaction solution, heat and react at 85 °C for 4 h under a nitrogen atmosphere, perform centrifugal separation, wash with N,N-dimethylformamide, and dry to obtain the first active filler C (denoted as S-Y-R(O)).

[0046] Preparation Example 4 20 parts of nano calcium carbonate were ultrasonically dispersed in 600 parts of toluene, 10 parts of (3-trimethoxysilyl)propyl 2-bromo-2-methylpropionate and 0.2 part of triethylamine were added, and the mixture was heated under reflux at 105 °C for 24 h, centrifuged, washed with ethanol, and dried to obtain modified nano calcium carbonate; 20 parts of the modified nano calcium carbonate and 15 parts of methyl methacrylate were dissolved and dispersed in 200 parts of N,N-dimethylformamide, the oxygen in the system was removed, 0.5 part of cuprous bromide and 0.5 part of pentamethyldiethylenetriamine were added, and the mixture was heated and reacted at 90 °C for 4 h under a nitrogen atmosphere to obtain a second reaction solution; Then, 15 parts of butyl acrylate and 2 parts of 4-hydroxybutyl acrylate were added to the second reaction solution, and the mixture was heated and reacted at 85 °C for 4 h under a nitrogen atmosphere, centrifuged, washed with N,N-dimethylformamide, and dried to obtain hydroxy-containing block polymer grafted calcium carbonate; 20 parts of the hydroxy-containing block polymer grafted calcium carbonate, 8 parts of N-aminoethyl-γ-aminopropyltrimethoxysilane and 0.1 part of triethylamine were dispersed in 400 parts of toluene, and the mixture was heated under reflux at 85 °C for 6 h, centrifuged, washed with water, and dried to obtain a second active filler A (denoted as S-Y-R(N), (N) represents the amino group grafted on the chain segment).

[0047] Preparation Example 5 20 parts of nano calcium carbonate were ultrasonically dispersed in 600 parts of toluene, 10 parts of (3-trimethoxysilyl)propyl 2-bromo-2-methylpropionate and 0.2 part of triethylamine were added, and the mixture was heated under reflux at 105 °C for 24 h, centrifuged, washed with ethanol, and dried to obtain modified nano calcium carbonate; 20 parts of the modified nano calcium carbonate, 15 parts of butyl acrylate and 2 parts of 4-hydroxybutyl acrylate were dispersed in 200 parts of N,N-dimethylformamide, the oxygen in the system was removed, 0.5 part of cuprous bromide and 0.5 part of pentamethyldiethylenetriamine were added, and the mixture was heated and reacted at 85 °C for 4 h under a nitrogen atmosphere to obtain a second reaction solution; Then, 15 parts of methyl methacrylate were added to the second reaction solution, and the mixture was heated and reacted at 90 °C for 4 h under a nitrogen atmosphere, centrifuged, washed with N,N-dimethylformamide, and dried to obtain hydroxy-containing block polymer grafted calcium carbonate; 20 parts of the hydroxy-containing block polymer grafted calcium carbonate, 8 parts of N-aminoethyl-γ-aminopropyltrimethoxysilane and 0.1 part of triethylamine were dispersed in 400 parts of toluene, and the mixture was heated under reflux at 85 °C for 6 h, centrifuged, washed with water, and dried to obtain a second active filler B (denoted as S-R(N)-Y).

[0048] Preparation Example 6 Disperse 20 parts of nano calcium carbonate ultrasonically in 600 parts of toluene, add 10 parts of (3-trimethoxysilyl)propyl 2-bromo-2-methylpropionate and 0.2 part of triethylamine, heat under reflux at 105 °C for 24 h, carry out centrifugal separation, wash with ethanol, and dry to obtain modified nano calcium carbonate; Dissolve and disperse 20 parts of the modified nano calcium carbonate, 15 parts of methyl methacrylate and 2 parts of hydroxypropyl methacrylate in 200 parts of N,N-dimethylformamide, remove the oxygen in the system, add 0.5 part of cuprous bromide and 0.5 part of pentamethyldiethylenetriamine, and carry out a heating reaction at 90 °C for 4 h under a nitrogen atmosphere to obtain a second reaction solution; Then add 15 parts of butyl acrylate to the second reaction solution, carry out a heating reaction at 85 °C for 4 h under a nitrogen atmosphere, carry out centrifugal separation, wash with N,N-dimethylformamide, and dry to obtain hydroxy-containing block polymer grafted calcium carbonate; Disperse 20 parts of the hydroxy-containing block polymer grafted calcium carbonate, 8 parts of N-(2-aminoethyl)-γ-aminopropyltrimethoxysilane and 0.1 part of triethylamine in 400 parts of toluene, heat under reflux at 85 °C for 6 h, carry out centrifugal separation, wash with water, and dry to obtain a second active filler C (denoted as S-Y(N)-R).

[0049] Preparation Example 7 It is substantially the same as Preparation Example 4, except that 3-aminopropyltriethoxysilane is used instead of N-(2-aminoethyl)-γ-aminopropyltrimethoxysilane to obtain a second active filler A1.

[0050] Preparation Example 8 It is substantially the same as Preparation Example 4, except that diethylenetriaminepropyltrimethoxysilane is used instead of N-(2-aminoethyl)-γ-aminopropyltrimethoxysilane to obtain a second active filler A2.

[0051] Preparation Example 9 Disperse 20 parts of nano calcium carbonate ultrasonically in 600 parts of toluene, add 10 parts of (3-trimethoxysilyl)propyl 2-bromo-2-methylpropionate and 0.2 part of triethylamine, heat under reflux at 105 °C for 24 h, carry out centrifugal separation, wash with ethanol, and dry to obtain modified nano calcium carbonate; Dissolve and disperse 20 parts of the modified nano calcium carbonate and 15 parts of methyl methacrylate in 200 parts of N,N-dimethylformamide, remove the oxygen in the system, add 0.5 part of cuprous bromide and 0.5 part of pentamethyldiethylenetriamine, and carry out a heating reaction at 90 °C for 4 h under a nitrogen atmosphere to obtain a first reaction solution; Then add 15 parts of butyl acrylate to the first reaction solution, carry out a heating reaction at 85 °C for 4 h under a nitrogen atmosphere, carry out centrifugal separation, wash with N,N-dimethylformamide, and dry to obtain a filler A (denoted as S-Y-R).

[0052] Preparation Example 10 20 parts of nano calcium carbonate were ultrasonically dispersed in 600 parts of toluene, 10 parts of (3-trimethoxysilyl)propyl 2-bromo-2-methylpropionate and 0.2 part of triethylamine were added, and the mixture was heated under reflux at 105 °C for 24 h, centrifuged, washed with ethanol, and dried to obtain modified nano calcium carbonate; 20 parts of the modified nano calcium carbonate and 15 parts of butyl acrylate were dispersed in 200 parts of N,N-dimethylformamide, the oxygen in the system was removed, 0.5 part of cuprous bromide and 0.5 part of pentamethyldiethylenetriamine were added, and the mixture was heated and reacted at 85 °C for 4 h under a nitrogen atmosphere to obtain a first reaction solution; Then, 15 parts of methyl methacrylate were added to the first reaction solution, and the mixture was heated and reacted at 90 °C for 4 h under a nitrogen atmosphere, centrifuged, washed with N,N-dimethylformamide, and dried to obtain filler B (denoted as S-R-Y).

[0053] Example 1

[0054] Preparation of a high-tough epoxy resin composition: 100 parts of epoxy resin E44, 15 parts of first active filler A, and 12 parts of ethylene glycol diglycidyl ether were mixed evenly to obtain a first component; 35 parts of polyamide 300, 8 parts of second active filler A, and 8 parts of polyetheramine 400 were mixed evenly to obtain a second component.

[0055] Example 2

[0056] It was substantially the same as Example 1, except that second active filler B was used instead of second active filler A.

[0057] Example 3

[0058] It was substantially the same as Example 1, except that second active filler C was used instead of second active filler A.

[0059] Example 4

[0060] It was substantially the same as Example 1, except that second active filler A1 was used instead of second active filler A.

[0061] Example 5

[0062] It was substantially the same as Example 1, except that second active filler A2 was used instead of second active filler A.

[0063] Example 6

[0064] It was substantially the same as Example 1, except that first active filler B was used instead of first active filler A.

[0065] Example 7

[0066] It is substantially the same as Example 1, except that the first active filler C is used instead of the first active filler A.

[0067] Comparative Example 1 It is substantially the same as Example 1, except that filler A is used to replace the first active filler A and the second active filler B respectively.

[0068] Comparative Example 2 It is substantially the same as Example 1, except that filler B is used to replace the first active filler A and the second active filler B respectively.

[0069] Test Section After mixing and curing the two components of the epoxy resin compositions of each example and comparative example, the tensile strength and elongation at break were tested according to GB / T 2567-2008, and the results are shown in Table 1.

[0070] Table 1

[0071] As can be seen from Table 1, the tensile strength of the cured products of the epoxy resin compositions obtained in each example is significantly higher than that of Comparative Example 1; the elongation at break of each example is higher than that of Comparative Example 2, and except for Example 2 and Example 6, the elongation at break of each example is higher than that of Comparative Example 1, indicating that the cured epoxy resin compositions obtained in each example can better balance strength and toughness. The fillers used in Comparative Example 1 and Comparative Example 2 are not grafted with active groups and have no reactivity with the components in the epoxy resin composition, so their crosslinking density is low and their strength is significantly lower than that of each example; at the same time, although the block polymer grafted on the filler surface can improve the dispersion of the filler in the system to a certain extent, compared with the block polymer with reactivity, the improvement of compatibility is limited. Although the flexible chain segments in the block polymer can disperse stress to a certain extent, due to poor compatibility, the improvement of toughness is limited; through comparison, it can be seen that the flexible chain segments grafted on the side far from the filler have a better effect on improving the compatibility of the filler and dispersing the tensile stress.

[0072] From Comparative Examples 1 to 3, 6, and 7, it can be seen that the positions of the hard segment and the flexible segment, and the grafting sites of the active groups in the first active filler and the second active filler all have a certain influence on the strength and toughness of the cured epoxy resin composition, and the cured epoxy resin composition obtained in Example 1 has better strength and toughness. From the results of Example 2 and Example 6, it can be seen that grafting the flexible chain segments on the outside of the filler has a better effect on improving the performance of the epoxy resin composition; according to Example 1, 3, and 7, grafting epoxy groups on the hard segment and amino groups on the soft segment, the epoxy resin composition can better balance strength and toughness.

[0073] It can be seen by comparing Examples 1, 4, and 5 that during the preparation process of the second active filler, the type of amino silane coupling agent has a certain influence on the strength and toughness of the cured epoxy resin composition. The second active filler obtained by using N-aminoethyl-γ-aminopropyltrimethoxysilane can better balance the strength and toughness of the cured epoxy resin composition.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A high-toughness epoxy resin composition, characterized in that: Including the following raw materials by weight: 100 parts of epoxy resin, 10-20 parts of first active filler, 10-20 parts of first active diluent, 25-40 parts of curing agent, 5-10 parts of second active filler, 5-10 parts of second active diluent; Wherein, the first active filler is a first block polymer grafted with a first filler, the first block polymer includes a first hard segment and a first soft segment, and the first block polymer includes an epoxy group; The second active filler is a second block polymer grafted with a second filler, the second block polymer includes a second hard segment and a second soft segment, and the second block polymer includes an amino group.

2. The high-toughness epoxy resin composition according to claim 1, characterized in that: The first hard segment includes an epoxy group; The second soft segment includes an amino group.

3. The high-toughness epoxy resin composition according to claim 2, characterized in that: The preparation method of the first active filler comprises the following steps: S1: silanization modification of the first filler using 2-bromo-2-methylpropionic acid (3-trimethoxysilyl) propyl ester, grafting free radical reactive groups on the surface of the first filler to obtain a modified first filler; S2: subjecting the modified first filler to a free radical polymerization reaction with methyl methacrylate and glycidyl methacrylate in an organic solvent under catalytic conditions, grafting a hard segment on the surface of the first filler, and obtaining a first reaction solution; S3: adding butyl acrylate to the first reaction solution, causing a free radical polymerization reaction in an organic solvent under catalytic conditions, and continuously polymerizing and grafting the soft segment on the hard segment to obtain a first active filler.

4. The high-toughness epoxy resin composition according to claim 3, characterized in that: The preparation method of the first active filler comprises the following steps: S1: Disperse 20 parts of the first filler, 5-15 parts of 2-bromo-2-methylpropionic acid (3-trimethoxysilyl)propyl ester, and 0.1-2 parts of triethylamine in 500-1000 parts of toluene, and reflux at 90-110° C. for 18-24 hours to obtain a modified first filler; S2: Disperse 20 parts of the modified first filler, 15-20 parts of methyl methacrylate, and 1-3 parts of glycidyl methacrylate in 150-300 parts by mass of N,N-dimethylformamide, use 0.1-1 parts of cuprous bromide and 0.1-1 parts of pentamethyldiethylenetriamine as catalysts, react at 80-90° C. under a protective atmosphere for 3-5 hours to obtain a first reaction solution; S3: adding 15 to 20 parts of butyl acrylate to the first reaction solution, reacting at 75 to 85° C. under a protective atmosphere for 3 to 5 hours to obtain a first active filler.

5. The high-toughness epoxy resin composition according to claim 2, characterized in that: The preparation method of the second active filler comprises the following steps: M1: The second filler is silanized using 2-bromo-2-methylpropionic acid (3-trimethoxysilyl) propyl ester to graft free radical reactive groups on the surface of the second filler to obtain a modified second filler; M2: The modified second filler and methyl methacrylate are subjected to a free radical polymerization reaction in an organic solvent under catalytic conditions, and a hard segment is grafted onto the surface of the second filler to obtain a second reaction solution; M3: adding butyl acrylate and 4-hydroxybutyl acrylate to the second reaction solution, causing free radical polymerization in an organic solvent under catalytic conditions, and continuously polymerizing and grafting soft segments on the hard segments to obtain hydroxyl-containing block polymer grafted fillers; M4: The hydroxyl-containing block polymer grafted filler is modified using an aminosilane coupling agent, so that the hydroxyl groups on the soft segments of the block polymer grafted filler react with the aminosilane coupling agent to obtain a second active filler.

6. The high-toughness epoxy resin composition according to claim 5, characterized in that: The preparation method of the second active filler comprises the following steps: M1: Disperse 20 parts of the second filler, 5-15 parts of 2-bromo-2-methylpropionic acid (3-trimethoxysilyl)propyl ester, and 0.1-2 parts of triethylamine in 500-1000 parts of toluene, and reflux at 90-110° C. for 18-24 hours to obtain a modified second filler; M2: Disperse 20 parts of the modified second filler and 15-20 parts of methyl methacrylate in 150-300 parts by mass of N,N-dimethylformamide, use 0.1-1 parts of cuprous bromide and 0.1-1 parts of pentamethyldiethylenetriamine as catalysts, react at 80-90°C in a protective atmosphere for 3-5 hours to obtain a second reaction solution; M3: adding 15-20 parts of butyl acrylate and 1-3 parts of 4-hydroxybutyl acrylate to the second reaction solution, reacting at 75-85° C. under a protective atmosphere for 3-5 hours to obtain a hydroxyl-containing block polymer graft filler; M4: Disperse 20 parts of hydroxyl-containing block polymer grafted filler, 5-10 parts of aminosilane coupling agent, and 0.1-1 part of triethylamine in 300-600 parts of toluene, and reflux at 80-100° C. for 3-8 hours to obtain a second active filler.

7. The high-toughness epoxy resin composition according to claim 5 or 6, characterized in that: The aminosilane coupling agent includes N-aminoethyl-γ-aminopropyltrimethoxysilane.

8. The high-toughness epoxy resin composition according to claim 1, characterized in that: The first reactive diluent includes epoxy-containing glycidyl ether, and the second reactive diluent includes amino-containing polyether amine.

9. The high-toughness epoxy resin composition according to claim 1, characterized in that: The high-toughness epoxy resin composition satisfies at least one of the following conditions: 1) The epoxy resin includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and bisphenol S epoxy resin; 2) The curing agent includes at least one of polyamide 300, polyamide 650 and polyamide 651; 3) The first filler and the second filler independently include at least one of nano calcium carbonate, nano silicon dioxide, and titanium dioxide.

10. A method for preparing a high-toughness epoxy resin composition, characterized in that: include: Providing a raw material for the high-toughness epoxy resin composition according to any one of claims 1 to 9; Mixing an epoxy resin, a first reactive filler, and a first reactive diluent to obtain a first component; mixing a curing agent, a second reactive filler, and a second reactive diluent to obtain a second component; The first component and the second component are mixed and cured to obtain a high-toughness epoxy resin composition.

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