CN116200002A - Epoxy resin composition, preparation method thereof, prepreg and glass fiber composite material - Google Patents

Abstract

The application discloses an epoxy resin composition and its preparation method, prepreg, and glass fiber composite material. The epoxy resin composition includes the following raw materials in parts by weight: 80-120 parts by weight of epoxy resin; 5-20 parts by weight of the toughening agent; 8-10 parts by weight of the curing agent; wherein, the nano-toughener is polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate triblock copolymer. The epoxy resin composition of the present application has high transparency and high toughness, and the prepreg prepared by the epoxy resin composition also has high transparency and high toughness, and the glass fiber composite material prepared by the prepreg not only has High transparency, also has high toughness.

Description

Epoxy resin composition and preparation method thereof, prepreg, and glass fiber composite material

Technical Field

The present application belongs to the technical field of composite materials, and specifically relates to an epoxy resin composition and a preparation method thereof, a prepreg, and a glass fiber composite material.

Background Art

Currently, there are two main transparent substrates for mobile phone back panels, glass or plastic (PC/PMMA composite material). Glass has high strength but poor toughness and is easily broken; PC/PMMA composite materials have good toughness but poor rigidity and are not easy to make a laminated structure. Transparent glass fiber composite materials have better toughness than glass and better rigidity than PC/PMMA composite materials. In addition, the laminated structure is conducive to making a rich decorative layer to obtain a variety of appearance effects.

Transparent glass fiber composite material is a composite material with epoxy resin as the resin matrix and continuous glass fiber as the reinforcement. Although it has certain toughness and rigidity, its toughness is still not enough to meet the requirements of the mobile phone back panel market. When the transparent glass fiber composite material is subjected to a drop ball test, the surface of the transparent glass fiber composite material will appear "white", resulting in appearance failure. The whitening is mainly due to the separation of the glass fiber and resin interface under dynamic impact, and the obvious light refraction at the interface, resulting in the "white" appearance phenomenon. In order to solve this problem, a toughening agent can be used to toughen the epoxy resin. However, the existing toughening agents (such as nitrile rubber, core-shell structure, thermoplastic elastomer) are themselves opaque, and the microphase scale formed is greater than 100nm. When light is transmitted in the matrix, light loss will occur, and the appearance transparency is poor. Therefore, the transparent glass fiber composite material prepared by the existing toughening agent does not have high transparency and cannot meet the application requirements of the mobile phone back panel market.

Summary of the invention

In order to solve the above technical problems, the present application provides an epoxy resin composition and a preparation method thereof, a prepreg, and a glass fiber composite material. The epoxy resin composition of the present application has high transparency and high toughness, and the prepreg prepared from the epoxy resin composition also has high transparency and high toughness. The glass fiber composite material prepared from the prepreg not only has high transparency, but also has high toughness, and can avoid separation of the glass fiber and resin interface under dynamic impact, resulting in the phenomenon of "whitening" appearance.

In order to achieve the above technical effects, the technical solutions adopted in this application are as follows:

In a first aspect, the present application provides an epoxy resin composition, which includes the following raw materials in parts by weight: 80 to 120 parts by weight of epoxy resin; 5 to 20 parts by weight of nano-toughening agent; and 8 to 10 parts by weight of curing agent; wherein the nano-toughening agent is a triblock copolymer of polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate.

In some embodiments, the weight ratio of the nano toughener to the epoxy resin is 1:16 to 1:8.

In some embodiments, the weight ratio of the curing agent to the epoxy resin is 1:14 to 1:9.

In some embodiments, the number average molecular weight of the polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate triblock copolymer is 15×10 ⁴ to 30×10 ⁴ .

In some embodiments, the viscosity of the polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate triblock copolymer is 400-1000 mPa.s.

In some embodiments, the epoxy resin is at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, and bisphenol S epoxy resin.

In some embodiments, the epoxy equivalent of the epoxy resin is 150-400 g/mol.

In some embodiments, the curing agent is an amine curing agent.

In some embodiments, the curing agent is at least one of ethylenediamine, diethylenetriamine, tetraethylenepentamine, triethylenetetramine, and dipropylenetriamine.

In some embodiments, the epoxy resin composition further comprises a diluent and/or a defoamer; the diluent is 5 to 10 parts by weight; the defoamer is 0.05 to 0.1 parts by weight.

In some embodiments, the diluent is at least one of n-butyl glycidyl ether, glycidyl methacrylate, tert-butylphenyl glycidyl ether, phenyl glycidyl ether, and trimethylolethane triglycidyl ether.

In some embodiments, the defoaming agent is a polyether defoaming agent.

In some embodiments, the polyether defoamer is a polyether-modified polysiloxane defoamer.

In some embodiments, the particle size of the polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate triblock copolymer is no greater than 100 nanometers.

In a second aspect, the present application provides a method for preparing an epoxy resin composition, the preparation method comprising:

Dispersing the nano toughener in the epoxy resin at a first temperature and a first stirring speed to prepare a nano toughener-epoxy resin solution; wherein the first temperature is 150-180° C., the first stirring speed is 1000-2000 rpm/min, and the nano toughener is a triblock copolymer of polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate;

At a second temperature and a second stirring speed, a curing agent is added to the nano toughening agent-epoxy resin solution, mixed evenly, and a curing reaction is carried out to obtain the epoxy resin composition; wherein the second temperature is 25-35°C, the second stirring speed is 400-600rpm/min, the curing reaction temperature is 120-150°C, and the curing reaction time is 120-180 minutes.

In some embodiments, in the preparation method, when the curing agent is added to the nano-toughening agent-epoxy resin solution, a defoaming agent and a diluent are added to the nano-toughening agent-epoxy resin solution; wherein the curing agent, the defoaming agent, and the diluent are added to the nano-toughening agent-epoxy resin solution in a predetermined order.

In a third aspect, the present application provides a prepreg, comprising glass fiber and the above-mentioned epoxy resin composition.

In some embodiments, the glass fiber has a gram weight of 50 to 150 g/cm ² .

In some embodiments, the content of the epoxy resin composition in the prepreg is 30-50%.

In a fourth aspect, the present application provides a glass fiber composite material, wherein the glass fiber composite material includes the above-mentioned prepreg.

The beneficial effects of the present application include but are not limited to: the epoxy resin composition of the present application is prepared from epoxy resin, nano toughening agent, and curing agent. The nano toughening agent is a triblock copolymer of polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate, in which light transmission will not cause light reflection, effectively avoiding light loss, and making the epoxy resin composition have good transparency; in addition, the side chain block of PMMA-PBA-PMMA has a polar group, which can form an interaction force with the functional group of the epoxy resin to form a nano-microphase separation structure, and the nano-microphase separation structure can effectively improve the toughness of the epoxy resin. Therefore, the epoxy resin composition has high transparency and high toughness, and the prepreg prepared from the epoxy resin composition also has high transparency and high toughness. The glass fiber composite material prepared from the prepreg also has high transparency and high toughness. Under dynamic impact, the separation of the glass fiber and the resin interface can be avoided, and the appearance of "whitening" phenomenon occurs.

It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings herein are incorporated into the specification and constitute a part of the specification of this application, illustrate embodiments consistent with the present application, and are used together with the specification to explain the technical solution of the present application. The drawings described below are some embodiments of the present application, but not all embodiments. For those skilled in the art, other drawings can be obtained based on these drawings without paying creative work.

Various objects, features and advantages of the present application will become more apparent by considering the following detailed description of embodiments of the present application in conjunction with the accompanying drawings.

FIG. 1 is a flow chart of a process for preparing an epoxy resin composition according to one embodiment.

FIG. 2 is a flow chart of a preparation process of a glass fiber composite material according to one embodiment.

DETAILED DESCRIPTION

In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application. It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments can be arbitrarily combined with each other.

The present application provides an epoxy resin composition and a preparation method thereof, a prepreg, and a glass fiber composite material.

The epoxy resin composition of the exemplary embodiment of the present application comprises the following raw materials in parts by weight:

Epoxy resin 80-120 parts by weight;

Nano toughening agent 5-20 parts by weight;

Curing agent 8-10 parts by weight;

Wherein, the nano toughening agent is a triblock copolymer of polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate.

The epoxy resin composition of the present application is prepared by reasonably controlling the contents of epoxy resin, nano toughening agent and curing agent to have high transparency and high toughness.

Epoxy resin is the main component of epoxy resin composition, which can be used as the resin matrix of glass fiber composite material, and has the function of protecting glass fiber, improving the cuttability and bundling property of glass fiber. Too high or too low content of epoxy resin will affect the mechanical properties of the glass fiber composite material formed subsequently. Among them, the content of epoxy resin is 80 to 120 parts by weight, and can also be 90 to 110 parts by weight, illustratively, 90 parts by weight, 95 parts by weight, 100 parts by weight, 105 parts by weight, and 110 parts by weight.

The nano toughening agent of the present application can be a triblock copolymer of polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate (PMMA-PBA-PMMA). When light is transmitted in a matrix made of the nano toughening agent, the nano toughening agent will not cause light reflection, effectively avoiding light loss and making the matrix transparent.

PMMA-PBA-PMMA is composed of three linear chains covalently bonded to each other, the main chain block is polybutyl acrylate, and the side chain block is polymethyl methacrylate. The side chain block of PMMA-PBA-PMMA has a polar group, which can form an interaction force with the functional group of the epoxy resin to form a nano-microphase separation structure. The cured epoxy resin forms a three-dimensional network structure, and the microphase separation structure dispersed in the network structure can effectively improve the toughness of the epoxy resin. Too low a content of the nano-toughening agent cannot achieve the desired toughening effect, and too high a content of the nano-toughening agent will affect the transparency of the epoxy resin composition. Among them, the content of the nano-toughening agent is 5 to 20 parts by weight, or 5 to 15 parts by weight, illustratively, 5 parts by weight, 8 parts by weight, 10 parts by weight, 12 parts by weight, and 15 parts by weight.

The curing agent is used to cure the epoxy resin. The epoxy resin itself is a thermoplastic linear structure, and it is difficult to prepare a glass fiber composite material with high toughness. The curing agent is used to react with the epoxy resin to generate a network of three-dimensional polymers, and the epoxy resin aggregate is encapsulated in the network, which is convenient for preparing a glass fiber composite material with high toughness. The curing agent and the polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate triblock copolymer react with the epoxy resin together to generate an epoxy resin composition with high toughness and high transparency. Among them, the content of the curing agent is 8 to 10 parts by weight, and illustratively, it is 8 parts by weight, 9 parts by weight, and 10 parts by weight. If the content of the curing agent is too low, the curing effect on the epoxy resin is not good; if the content of the curing agent is too high, the production cost will be increased, resulting in a waste of resources.

In the exemplary embodiments provided in the present application, the weight ratio of the nano toughening agent to the epoxy resin is 1:16 to 1:8.

In the exemplary embodiments provided in the present application, the weight ratio of the curing agent to the epoxy resin is 1:14 to 1:9.

The ratio of epoxy resin to nano toughening agent or curing agent will affect the transparency and toughness of the epoxy resin composition. If the weight ratio of nano toughening agent to epoxy resin or the weight ratio of curing agent to epoxy resin is too low, the toughness of the epoxy resin composition formed is poor; if the weight ratio of nano toughening agent to epoxy resin is too high, the transparency of the epoxy resin composition will be affected; if the weight ratio of curing agent to epoxy resin is too high, the production cost will be increased and resources will be wasted. Among them, the weight ratio of nano toughening agent to epoxy resin is 1:16 to 1:8, and can also be 1:14 to 1:10, illustratively, 1:14, 1:13, 1:12, 1:11, 1:10; the weight ratio of curing agent to epoxy resin is 1:14 to 1:9, and can also be 1:13 to 1:10, illustratively, 1:13, 1:12, 1:11, 1:10.

In the exemplary embodiments provided in the present application, the number average molecular weight of the polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate triblock copolymer is 15×10 ⁴ to 30×10 ⁴ .

It should be noted that the polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate triblock copolymer is only used to more clearly explain the technical solution of the present application, and is not a limitation of the present application. Other nano-toughened copolymers that can achieve the technical effects of the present application are also within the protection scope of the present application.

The number average molecular weight of PMMA-PBA-PMMA will affect its compatibility with epoxy resin and toughening effect. If the molecular weight is too large, the compatibility with epoxy resin will be worse; if the molecular weight is too small, the toughening effect will be poor. The number average molecular weight of PMMA-PBA-PMMA is 15×10 ⁴ to 30×10 ⁴ , or 20×10 ⁴ to 25×10 ⁴ , illustratively, 21×10 ⁴ , 22×10 ⁴ , 23×10 ⁴ , 24×10 ⁴ .

In the exemplary embodiments provided in the present application, the viscosity of the polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate triblock copolymer is 400-1000 mPa.s.

The viscosity of PMMA-PBA-PMMA is too high, which is not conducive to the curing reaction; the viscosity of PMMA-PBA-PMMA is too low, and the toughening effect is not good. Among them, the viscosity of PMMA-PBA-PMMA is 400-1000mPa.s, and can also be 600-800mPa.s, illustratively, 600mPa.s, 700mPa.s, and 800mPa.s.

In the exemplary embodiments provided in the present application, the epoxy resin is at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, and bisphenol S epoxy resin.

The bisphenol A epoxy resin, bisphenol F epoxy resin and/or bisphenol S epoxy resin have higher activity in reaction with the curing agent, and the epoxy resin composition obtained has stronger toughness.

In the exemplary embodiments provided in the present application, the epoxy equivalent of the epoxy resin is 150 to 400 g/mol.

In the exemplary embodiments provided in the present application, the curing agent is an amine curing agent.

Amine curing agents are easily soluble in epoxy resins. Their curing effect on epoxy resins is that the active hydrogen on the nitrogen atom opens the epoxy group, causing it to cross-link and cure. Moreover, the amine curing agent itself is colorless, so the cured epoxy resin is colorless and transparent.

In the exemplary embodiments provided in the present application, the curing agent is at least one of ethylenediamine, diethylenetriamine, tetraethylenepentamine, triethylenetetramine, and dipropylenetriamine.

Ethylenediamine, diethylenetriamine, tetraethylenepentamine, triethylenetetramine, and dipropylenetriamine are aliphatic polyamines with high activity. They can crosslink and cure epoxy resins at room temperature with high reaction yields.

In the exemplary embodiments provided in the present application, the epoxy resin composition further includes a diluent and/or a defoamer; the diluent is 5 to 10 parts by weight; and the defoamer is 0.05 to 0.1 parts by weight.

The diluent is used to reduce the viscosity of the curing reaction system. The diluent of the appropriate content is selected to adjust the viscosity of the curing reaction system, increase fluidity, and facilitate the smooth progress of the curing reaction. The content of the diluent is 5 to 10 parts by weight, or 6 to 8 parts by weight, illustratively, 6 parts by weight, 7 parts by weight, and 8 parts by weight.

During the curing reaction, a large amount of foam will appear, which seriously affects the yield and performance of the epoxy resin cured product, and also causes a waste of raw materials; the defoamer can effectively reduce the foam during the reaction, thereby improving the yield and performance of the cured product and avoiding a waste of raw materials. The content of the defoamer is 0.05 to 0.1 parts by weight, and can also be 0.06 to 0.08 parts by weight, illustratively, 0.06 parts by weight, 0.07 parts by weight, and 0.08 parts by weight.

In the exemplary embodiments provided in the present application, the diluent is at least one of n-butyl glycidyl ether, glycidyl methacrylate, tert-butylphenyl glycidyl ether, phenyl glycidyl ether, and trimethylolethane triglycidyl ether.

n-Butyl glycidyl ether, glycidyl methacrylate, tert-butylphenyl glycidyl ether, phenyl glycidyl ether and trimethylolethane triglycidyl ether are reactive curing agents. Their molecular chains contain epoxy groups, which can undergo cross-linking reactions with curing agents to form a network structure and become part of the cross-linked network structure of epoxy resin cured products. They have no effect on the performance of the cured products, but can also increase the toughness of the curing system and improve the curing effect and curing performance of the epoxy resin.

In the exemplary embodiment provided in the present application, the defoaming agent is a polyether defoaming agent.

In the exemplary embodiments provided in the present application, the polyether defoaming agent is a polyether-modified polysiloxane defoaming agent.

Polyether defoamers, especially polyether-modified polysiloxane defoamers, not only have low surface tension and strong defoaming effect, but also have low volatility, are non-toxic, non-polluting, and are physiologically inert.

In the exemplary embodiment provided in the present application, the particle size of the polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate triblock copolymer is not greater than 100 nanometers.

When the particle size of PMMA-PBA-PMMA is not greater than 100 nanometers, the effect of preventing light reflection is better and the transparency of the matrix is significantly improved. The particle size of PMMA-PBA-PMMA can also be 50 to 100 nanometers.

The exemplary embodiment of the present application provides a method for preparing an epoxy resin composition, as shown in FIG1 , comprising:

Step S100: dispersing the nano toughener into the epoxy resin at a first temperature and a first stirring speed to prepare a nano toughener-epoxy resin solution; wherein the first temperature is 150-180° C., the first stirring speed is 1000-2000 rpm/min, and the nano toughener is a triblock copolymer of polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate.

The nano toughener is a polymer material. At a suitable temperature and stirring speed, the nano toughener is dispersed in the epoxy resin, which is conducive to the dissolution of the nano toughener in the epoxy resin, forming a transparent and uniform nano toughener-epoxy resin solution without affecting the performance of various components. Among them, the first temperature is 150-180°C, or 160-170°C, illustratively, 160°C, 165°C, 170°C; the first stirring speed is 1000-2000rmp/min, or 1200-1800rmp/min, illustratively, 1200rmp/min, 1300rmp/min, 1500rmp/min, 1700rmp/min, 1800rmp/min.

Step S200: At a second temperature and a second stirring speed, adding a curing agent to the nano toughening agent-epoxy resin solution, mixing evenly, and performing a curing reaction to obtain an epoxy resin composition; wherein the second temperature is 25 to 35°C, the second stirring speed is 400 to 600 rpm/min, the curing reaction temperature is 120 to 150°C, and the curing reaction time is 120 to 180 minutes.

At room temperature (i.e., the temperature is 25-35°C) and the stirring speed is 400-600rpm/min, the curing agent is dispersed into the nano toughening agent-epoxy resin solution, and mixed evenly to form a uniform solution. The temperature of this process cannot be too high, otherwise the curing agent will induce a cross-linking reaction of the epoxy resin, affecting the subsequent curing reaction. The curing reaction is carried out at a temperature of 120-150°C, and the curing reaction time is 120-180 minutes, which can ensure that the curing reaction can be carried out more completely and thoroughly, thereby obtaining an epoxy resin composition with high transparency and high toughness. Among them, the curing reaction temperature can also be 130-140°C, illustratively, 130°C, 135°C, 140°C; the curing reaction time can also be 130-160 minutes, illustratively, 130 minutes, 140 minutes, 150 minutes, 160 minutes.

In the exemplary embodiment provided in the present application, in step S200, when the curing agent is added to the nano-toughening agent-epoxy resin solution, the defoaming agent and the diluent are added to the nano-toughening agent-epoxy resin solution; wherein the curing agent, the defoaming agent, and the diluent are added to the nano-toughening agent-epoxy resin solution in a predetermined order; for example, the curing agent can be added to the nano-toughening agent-epoxy resin solution first, then the defoaming agent is added, and finally the diluent is added; the curing agent, the defoaming agent, and the diluent can also be added to the nano-toughening agent-epoxy resin solution at the same time; there is no limitation on this.

In the process of preparing the epoxy resin composition, defoamer and diluent may not be added, or at least one of the defoamer and diluent may be added. The curing agent, defoamer and diluent may be added to the nano toughening agent-epoxy resin solution in a predetermined order. For example, the curing agent, defoamer and diluent are added to the nano toughening agent-epoxy resin solution in sequence.

In the preparation method of the epoxy resin composition of the exemplary embodiment provided in the present application, the epoxy resin is 80 to 120 parts by weight; the nano toughener is 5 to 20 parts by weight; the curing agent is 8 to 10 parts by weight; the diluent is 5 to 10 parts by weight; and the defoaming agent is 0.05 to 0.1 parts by weight.

The preparation method of the glass fiber composite material of the exemplary embodiment of the present application, as shown in FIG2, comprises: obtaining an epoxy resin composition by curing reaction of epoxy resin, nano toughening material, curing agent, defoaming agent, and diluent; impregnating the solution of the epoxy resin composition onto the surface of glass fiber by an impregnation process to obtain a prepreg; and forming the prepreg into a glass fiber composite material by a molding process. In the curing reaction, the defoaming agent and the diluent may not be added.

The prepreg according to an exemplary embodiment of the present application includes glass fiber and the epoxy resin composition of the present application.

The epoxy resin composition of the present application is impregnated into the surface of the glass fiber through an impregnation process to obtain a prepreg having high transparency and high toughness. The glass fiber may be an alkali-free glass fiber.

In the exemplary embodiment of the present application, the gram weight of the glass fiber is 50-150 g/cm ² .

When the gram weight of the glass fiber in the prepreg is 50-150g/ ^cm2 , the transparency and mechanical properties of the glass fiber can be well taken into account; if the gram weight is too large, the transparency will decrease; if the gram weight is too small, the mechanical properties will decrease.

In an exemplary embodiment of the present application, the content of the epoxy resin composition in the prepreg is 30-50%.

The glass fiber composite material according to the exemplary embodiment of the present application includes the prepreg of the present application.

The prepreg of the present application is made into a glass fiber composite material through a molding process, and the glass fiber composite material has high transparency and high toughness. The molding process is a compression molding process or an autoclave molding process.

The compression molding process is a process in which a certain molding material is placed in a metal mold and solidified at a certain temperature and pressure. The temperature and pressure are determined according to the actual application.

Autoclave molding refers to a process in which a composite material blank formed by stacking a single layer of prepreg in a predetermined direction is placed in an autoclave and cured at a certain temperature and pressure. The temperature and pressure are determined according to the actual application.

In order to more clearly explain the technical solution of the present application, Examples 1 to 10 of the epoxy resin composition of the present application are listed herein, and Comparative Examples 1 to 2 are also listed. Comparative Example 1 is an epoxy resin; Comparative Example 2 is an epoxy resin modified by an elastomer.

The preparation method of the epoxy resin composition of Examples 1 to 10 comprises:

At a first temperature and a first stirring speed, the nano toughener is dispersed in the epoxy resin to prepare a nano toughener-epoxy resin solution; wherein the nano toughener is a triblock copolymer of polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate;

At the second temperature and the second stirring speed, the curing agent, the defoaming agent and the diluent are sequentially added to the nano toughening agent-epoxy resin solution, mixed evenly, and subjected to curing reaction to obtain an epoxy resin composition.

The formulations of the epoxy resin compositions of Examples 1 to 10 are shown in Table 1.

Table 1 Formula of epoxy resin composition of Examples 1 to 10

Table 1 Formula of the epoxy resin composition of Examples 1 to 10 (continued)

The specific process parameters for preparing the epoxy resin compositions of Examples 1 to 10 are shown in Table 2.

Table 2 Specific process parameters for preparing the epoxy resin compositions of Examples 1 to 10

Example 1 Example 2 Example 3 Example 4 Example 5 First temperature (℃) 170 165 175 160 180 First stirring speed (rpm/min) 1500 1200 1400 1700 2000 Second temperature (℃) 25 30 35 30 35 Second stirring speed (rpm/min) 500 450 550 480 430 Curing reaction temperature (℃) 130 120 140 145 125 Curing reaction time (minutes) 140 150 160 130 150

Table 2 Specific process parameters for preparing the epoxy resin compositions of Examples 1 to 10 (continued)

The epoxy resin compositions of Examples 1 to 10, the epoxy resin of Comparative Example 1, and the elastomer-modified epoxy resin of Comparative Example 2 were impregnated onto the surface of glass fibers by an impregnation process to obtain respective prepregs, and the prepregs were made into glass fiber composite materials by a molding process. The gram weight of the glass fiber was 50 to 150 g/cm ² , and the content of the epoxy resin composition in the prepreg was 30-50%. The glass fiber composite materials of Examples 1 to 10, Comparative Example 1, and Comparative Example 2 were subjected to a falling ball impact test, a transmittance test, and a pendulum impact toughness test, and the performance test results are shown in Table 3.

Drop ball impact test: Place the glass composite material to be tested on the test board and mark the test points on the surface. Drop a 65g solid steel ball vertically from different heights of 10cm, 15cm, 20cm, 25cm, 30cm, 35cm, 40cm, 45cm, 50cm, and 55cm to hit the marked test points. Record the drop ball height H corresponding to the appearance failure of the glass fiber composite material surface such as whitening, cracks, or silver streaks.

Transmittance test: In an environment of temperature of 30° C. and humidity of 65%, the transmittance of the glass fiber compositions of the examples and comparative examples was measured using a transmittance meter.

Pendulum impact toughness test: with reference to the national standard GB 8809-88, a pendulum impact tester was used to test the pendulum impact toughness of the glass fiber composite materials of the embodiments and comparative examples.

Table 3 Performance test results of Examples 1 to 10 and Comparative Examples 1 to 2

Ball drop height H (cm) Light transmittance (%) Pendulum impact toughness (%) Example 1 50 85 28.8 Example 2 45 80 27.6 Example 3 40 90 28.1 Example 4 55 75 29.2 Example 5 50 84 28.5 Example 6 55 88 28.4 Example 7 45 79 28.8 Example 8 55 92 29.7 Example 9 50 83 27.9 Example 10 40 80 28.3 Comparative Example 1 15 70 15.1 Comparative Example 2 40 60 28.2

From the performance test results of the examples and comparative examples in Table 3, it can be seen that the ball drop height H of Examples 1 to 10 of the present application is much greater than the ball drop height of Comparative Example 1, and the pendulum impact toughness of Examples 1 to 10 of the present application is higher than the pendulum impact toughness of Comparative Example 1, and is equivalent to the pendulum impact toughness of Comparative Example 2, indicating that the epoxy resin composition prepared by the nano toughening agent has high toughness, thereby improving the toughness of the prepared glass fiber composite material; the light transmittance of Examples 1 to 10 is much higher than the light transmittance of Comparative Example 2, and slightly higher than the light transmittance of Comparative Example 1, indicating that the transparency of the epoxy resin composition prepared by the nano toughening agent is not only higher than the transparency of the modified epoxy resin prepared by the elastomer, but also higher than the transparency of the epoxy resin. Therefore, the glass fiber composite material prepared by the epoxy resin composition of the present application has high toughness.

The epoxy resin composition of the present application is prepared from epoxy resin, nano toughening agent and curing agent. Wherein the nano toughening agent is PMMA-PBA-PMMA, PMMA-PBA-PMMA, light transmission therein will not cause light reflection, effectively avoid light loss, and make the transparency of the epoxy resin composition good; In addition, the side chain block of PMMA-PBA-PMMA has a polar group, which can form an interaction force with the functional group of the epoxy resin to form a nano-micro phase separation structure, and the nano-micro phase separation structure can effectively improve the toughness of the epoxy resin. Therefore, the epoxy resin composition has high transparency and high toughness, and the prepreg prepared by the epoxy resin composition also has high transparency and high toughness. The glass fiber composite material prepared by the prepreg also has high transparency and high toughness. Under dynamic impact, it is possible to avoid separation of the glass fiber and the resin interface, and the appearance of the phenomenon of "whitening" occurs.

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 above embodiments, a person skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims (20)

1. An epoxy resin composition is characterized by comprising the following raw materials in parts by weight:

80-120 parts by weight of epoxy resin;

5-20 parts by weight of nano toughening agent;

8-10 parts of curing agent;

wherein the nanometer toughening agent is polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate triblock copolymer.

2. The epoxy resin composition of claim 1, wherein the weight ratio of the nano-toughener to the epoxy resin is from 1:16 to 1:8.

3. The epoxy resin composition according to claim 1, wherein the weight ratio of the curing agent to the epoxy resin is 1:14 to 1:9.

4. The epoxy resin composition according to claim 1, wherein the polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate triblock copolymer has a number average molecular weight of 15X 10 ⁴ ～30×10 ⁴ 。

5. The epoxy resin composition according to claim 1, wherein the polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate triblock copolymer has a viscosity of 400 to 1000mpa.s.

6. The epoxy resin composition according to claim 1, wherein the epoxy resin is at least one of bisphenol a type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin.

7. The epoxy resin composition according to claim 1, wherein the epoxy resin has an epoxy equivalent of 150 to 400g/moL.

8. The epoxy resin composition according to claim 1, wherein the curing agent is an amine curing agent.

9. The epoxy resin composition according to claim 1, wherein the curing agent is at least one of ethylenediamine, diethylenetriamine, tetraethylenepentamine, triethylenetetramine, and dipropylenetriamine.

10. The epoxy resin composition of claim 1, wherein the epoxy resin composition further comprises a diluent and/or an antifoaming agent; the diluent is 5-10 parts by weight; the defoaming agent is 0.05 to 0.1 weight part.

11. The epoxy resin composition according to claim 10, wherein the diluent is at least one of n-butyl glycidyl ether, glycidyl methacrylate, tert-butylphenyl glycidyl ether, phenyl glycidyl ether, and trimethylolethane triglycidyl ether.

12. The epoxy resin composition according to claim 10, wherein the defoamer is a polyether defoamer.

13. The epoxy resin composition of claim 12, wherein the polyether defoamer is a polyether modified polysiloxane defoamer.

14. The epoxy resin composition of claim 1, wherein the polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate triblock copolymer has a particle size of not more than 100 nm.

15. A method of preparing an epoxy resin composition according to any one of claims 1 to 14, comprising:

dispersing the nano toughening agent into epoxy resin at a first temperature and a first stirring speed to prepare a nano toughening agent-epoxy resin solution; wherein the first temperature is 150-180 ℃, the first stirring speed is 1000-2000 rmp/min, and the nano toughening agent is polymethyl methacrylate-polybutyl acrylate-polymethyl methacrylate triblock copolymer;

adding a curing agent into the nano toughening agent-epoxy resin solution at a second temperature and a second stirring speed, uniformly mixing, and performing curing reaction to obtain the epoxy resin composition; wherein the second temperature is 25-35 ℃, the second stirring speed is 400-600 rpm/min, the curing reaction temperature is 120-150 ℃, and the curing reaction time is 120-180 minutes.

16. The method of preparing according to claim 15, wherein an antifoaming agent and a diluent are added to the nano-toughener-epoxy solution while the curing agent is added to the nano-toughener-epoxy solution; wherein the curing agent, the defoamer, and the diluent are added to the nano-toughener-epoxy resin solution in a predetermined order.

17. A prepreg characterized in that the prepreg comprises glass fibers and an epoxy resin composition according to any one of claims 1-14.

18. A prepreg according to claim 17, wherein the glass fibres have a grammage of 50 to 150g/cm ² 。

19. A prepreg according to claim 17, wherein the epoxy resin composition in the prepreg is in the range 30 to 50%.

20. A glass fiber composite comprising the prepreg according to any one of claims 17 to 19.

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