A rapidly curable epoxy resin based glass fiber composite material and a method for producing the same

Abstract

The application relates to the technical field of glass fiber composite materials, and discloses a rapidly solidified epoxy resin-based glass fiber composite material and a preparation method thereof, the method comprising the following steps: pretreating a glass fiber fabric, preparing a rapidly solidified resin system, impregnating and pre-solidifying, layering and mold forming, demolding and post-processing; by adopting the rapidly solidified resin system containing specific epoxy resin, latent curing agent and accelerant, the activation energy of the solidification reaction is reduced, the solidification reaction rate of the resin system is accelerated, the rapid forming of the composite material is realized, and the production efficiency is improved; the interface bonding force between the glass fiber and the epoxy resin matrix is enhanced by pretreating the glass fiber fabric with a silane coupling agent; the toughness of the solidified product is improved by adding a toughening agent in the resin system; and the synergistic effect of the two guarantees that the composite material finally has high mechanical strength.

Description

Technical Field

[0001] This invention relates to the field of glass fiber composite materials technology, specifically to a rapidly curable epoxy resin-based glass fiber composite material and its preparation method. Background Technology

[0002] Epoxy resin-based glass fiber composites possess excellent mechanical properties, corrosion resistance, and chemical stability; low volume shrinkage during processing; and low cost, making them widely used in construction, communications and transportation, sporting goods, electronics, aerospace, and other fields. As global efforts to conserve energy and reduce emissions and address the greenhouse effect continue, the application of composite materials in large aircraft, wind turbine blades, automotive parts, oil extraction sucker rods, and power transmission cables will further promote energy conservation and emission reduction.

[0003] Currently, in the preparation process of epoxy resin-based glass fiber composites, the conventional resin system has a slow curing speed, resulting in a long molding cycle and low production efficiency; the interfacial bonding force between glass fiber and resin matrix is ​​insufficient, which easily affects the final mechanical strength of the composite material.

[0004] Therefore, a rapidly curable epoxy resin-based glass fiber composite material and its preparation method are proposed to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a rapidly curable epoxy resin-based glass fiber composite material and its preparation method, solving the problems of long molding cycles, low production efficiency, and insufficient interfacial bonding between glass fiber and resin matrix mentioned in the background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a rapidly curable epoxy resin-based glass fiber composite material, comprising the following steps: Step 1: Pretreatment of glass fiber fabric. Immerse the glass fiber fabric in a silane coupling agent treatment solution and treat it at 40-60℃ for 10-30 minutes. After taking it out, dry it at 80-100℃ for 0.5-1.5 hours to obtain the pretreated glass fiber fabric. Step 2: Preparation of the rapid curing resin system. Bisphenol A type epoxy resin, alicyclic epoxy resin, latent curing agent, accelerator, toughening agent and inorganic thermally conductive filler are added to a vacuum stirring and dispersing device. The mixture is stirred and mixed at 25-40℃ and 200-400 rpm for 15-30 minutes. Then, the vacuum is drawn to -0.08 to -0.1 MPa and held for 5-10 minutes to remove air bubbles, thus obtaining the rapid curing resin system. Step 3: Impregnation and pre-curing. The pretreated glass fiber fabric obtained in Step 1 is passed through an impregnation tank or coating equipment to be fully impregnated with the fast-curing resin system obtained in Step 2. The resin content is controlled at 35%-45%. The impregnated glass fiber fabric is then passed through an oven at 60-80℃ for 1-3 minutes for pre-curing treatment to obtain the prepreg. Step 4: Laying up and molding. Lay up the multi-layer prepreg obtained in Step 3 in the preset direction and place it into the mold cavity preheated to 80-100℃. After closing the mold, apply a pressure of 5-15MPa and keep it at 120-140℃ for 8-15 minutes for heat preservation and pressure curing. Then, raise the temperature to 150-170℃ for post-treatment for 20-40 minutes. Step 5: Demolding and post-treatment. After the pressure holding is completed, cool to below 60°C, demold to obtain composite material blank, and then place the blank in an oven at 140-160°C for 1-2 hours of post-curing treatment to obtain the rapidly curable epoxy resin-based glass fiber composite material. In step two, the rapid-curing resin system comprises the following components by weight: 50-70 parts of bisphenol A epoxy resin, 20-30 parts of alicyclic epoxy resin, 3-8 parts of latent curing agent, 0.5-2 parts of accelerator, 5-15 parts of toughening agent, and 10-25 parts of inorganic thermally conductive filler.

[0007] Preferably, in step one, the silane coupling agent treatment solution is prepared by the following method: Mix γ-aminopropyltriethoxysilane, ethanol and deionized water in a volume ratio of 1:8:1, adjust the pH to 4.5-5.5 with acetic acid, and use after stirring and aging at room temperature for 2-24 hours.

[0008] Preferably, in step two, the alicyclic epoxy resin is 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate or vinyl cyclohexene dioxide, and the latent curing agent is at least one of dicyandiamide, adipic acid dihydrazide, or boron trifluoride-monoethylamine complex.

[0009] Preferably, in step two, the accelerator is at least one of 2-methylimidazole, 2-ethyl-4-methylimidazole, or 1-cyanoethyl-2-ethyl-4-methylimidazole, and the toughening agent is at least one of carboxyl-terminated butadiene-acrylonitrile rubber, polyurethane-modified epoxy resin, or core-shell structured rubber particles.

[0010] Preferably, in step two, the inorganic thermally conductive filler is at least one of spherical alumina, aluminum nitride, or boron nitride that has been surface-treated with a silane coupling agent, and its average particle size D50 is 1-10 micrometers.

[0011] Preferably, in step three, the rapid-curing resin system is coated onto both sides of the fiberglass fabric using impregnation, blade coating, or slot coating methods. The resin content of the fiberglass fabric is controlled to be 35%-45% by adjusting process parameters, and the resin coating amount per unit area is 200-350 g / m². When using the dip-resin method, the linear speed ratio of the guide roller to the extrusion roller in the dip-resin tank should be controlled to be 1:1.1-1.3; When using a scraper coating method, the gap between the scraper and the bearing surface should be controlled to be 0.15-0.40 mm; When using slit coating, the slit width of the coating head should be controlled to be 0.10-0.25mm, and the delivery pressure of the metering pump should be 0.2-0.6MPa.

[0012] Preferably, in step four, the layup method is any one of unidirectional layup, orthogonal layup, or quasi-isotropic layup, and the preheating temperature of the mold cavity is 90±5℃.

[0013] Preferably, in step four, during the heat preservation and pressure curing process at 120-140℃, the temperature rise rate of the mold is 3-5℃ / minute; The heating rate from 120-140℃ to 150-170℃ is 2-3℃ / minute.

[0014] Preferably, in step five, cooling involves circulating water at 20-30°C into the cooling channel of the mold while maintaining pressure, cooling it to below 60°C at a rate of 5-10°C / minute.

[0015] A rapidly curable epoxy resin-based glass fiber composite material, the composite material comprising a reinforcing phase and a resin matrix phase, wherein the reinforcing phase is a glass fiber fabric surface-treated with a silane coupling agent, and the resin matrix phase is composed of bisphenol A type epoxy resin, alicyclic epoxy resin, a latent curing agent, an accelerator, a toughening agent, and an inorganic thermally conductive filler; The surface treatment with the silane coupling agent is achieved by immersing the glass fiber fabric in a silane coupling agent treatment solution and then drying it. The silane coupling agent treatment solution contains γ-aminopropyltriethoxysilane. The components in the resin matrix phase, by weight, are as follows: 50-70 parts of bisphenol A type epoxy resin, 20-30 parts of alicyclic epoxy resin, 3-8 parts of latent curing agent, 0.5-2 parts of accelerator, 5-15 parts of toughening agent, and 10-25 parts of inorganic thermally conductive filler.

[0016] Compared with the prior art, the present invention provides a rapidly curable epoxy resin-based glass fiber composite material and its preparation method, which has the following beneficial effects: 1. In this invention, by employing a rapid curing resin system containing a specific epoxy resin, a latent curing agent, and an accelerator, the activation energy of the curing reaction is reduced, and the curing reaction rate of the resin system is accelerated, thereby achieving rapid molding of composite materials and improving production efficiency.

[0017] 2. In this invention, the interfacial bonding force between the glass fiber and the epoxy resin matrix is ​​enhanced by pretreating the glass fiber fabric with a silane coupling agent; the toughening agent is added to the resin system to improve the toughness of the cured product; the synergistic effect of the two ensures that the composite material ultimately obtains high mechanical strength.

[0018] 3. In this invention, by compounding inorganic thermally conductive fillers into a rapid-curing resin system, the thermal conductivity of the composite material is improved while achieving rapid curing of the material; the resin system and curing process involved can maintain excellent heat resistance of the composite material while improving curing speed and thermal conductivity. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: A method for preparing a rapidly curable epoxy resin-based glass fiber composite material, comprising the following steps: Step 1: Pretreatment of glass fiber fabric. Immerse the glass fiber fabric in a silane coupling agent treatment solution and treat it at 40°C for 10 minutes. After taking it out, dry it at 80°C for 0.5 hours to obtain the pretreated glass fiber fabric. Step 2: Preparation of rapid curing resin system. Bisphenol A type epoxy resin, alicyclic epoxy resin, latent curing agent, accelerator, toughening agent and inorganic thermally conductive filler are added to a vacuum stirring and dispersing device and stirred and mixed at 25°C and 200 rpm for 15 minutes. Then, the vacuum is drawn to -0.08MPa and held for 5 minutes to remove air bubbles, thus obtaining the rapid curing resin system. Step 3: Impregnation and pre-curing. The pretreated glass fiber fabric obtained in Step 1 is passed through an impregnation tank to be fully impregnated by the fast-curing resin system obtained in Step 2. The resin content is controlled at 35%. The impregnated glass fiber fabric is then passed through a drying tunnel at 60°C for 1 minute for pre-curing treatment to obtain the prepreg. Step 4: Laying up and molding. Lay up the multi-layer prepreg obtained in Step 3 in the preset direction and place it into the mold cavity preheated to 80°C. After closing the mold, apply a pressure of 5MPa and keep it at 120°C for 8 minutes to cure. Then, heat it to 150°C for 20 minutes. Step 5: Demolding and post-treatment. After the pressure holding is completed, cool to below 60°C, demold to obtain composite material blank, and then place the blank in an oven at 140°C for 1 hour of post-curing treatment to obtain a rapidly curable epoxy resin-based glass fiber composite material. In step two, the rapid-curing resin system comprises the following components by weight: 50 parts of bisphenol A type epoxy resin, 20 parts of alicyclic epoxy resin, 3 parts of latent curing agent, 0.5 parts of accelerator, 5 parts of toughening agent, and 10 parts of inorganic thermally conductive filler.

[0021] In step one, the silane coupling agent treatment solution is prepared by the following method: Mix γ-aminopropyltriethoxysilane, ethanol and deionized water in a volume ratio of 1:8:1, adjust the pH to 4.5 with acetic acid, and use after stirring and aging at room temperature for 2 hours.

[0022] In step two, the alicyclic epoxy resin is 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, and the latent curing agent is dicyandiamide.

[0023] In step two, the accelerator is 2-methylimidazole and the toughening agent is carboxyl-terminated nitrile rubber.

[0024] In step two, the inorganic thermally conductive filler is spherical alumina surface-treated with silane coupling agent, with an average particle size D50 of 1 micrometer.

[0025] In step three, a rapid-curing resin system is coated onto both sides of the fiberglass fabric using an impregnation method. The resin content of the fiberglass fabric is controlled to be 35% by adjusting process parameters, and the resin coating amount per unit area is 200 g / m². When using the dip-resin method, the linear speed ratio of the guide roller to the extrusion roller in the dip-resin tank is controlled to be 1:1.1.

[0026] In step four, the layup method is unidirectional layup, and the preheating temperature of the mold cavity is 85℃.

[0027] In step four, during the heat preservation and pressure curing process at 120℃, the temperature rise rate of the mold is 3℃ / minute; The heating rate from 120℃ to 150℃ is 2℃ / minute.

[0028] In step five, cooling involves circulating water at 20°C into the cooling channel of the mold while maintaining pressure, cooling it to below 60°C at a rate of 5°C / minute.

[0029] The composite material includes a reinforcing phase and a resin matrix phase. The reinforcing phase is a glass fiber fabric surface-treated with a silane coupling agent. The resin matrix phase consists of bisphenol A type epoxy resin, alicyclic epoxy resin, latent curing agent, accelerator, toughening agent and inorganic thermally conductive filler. The silane coupling agent surface treatment is achieved by immersing the glass fiber fabric in a silane coupling agent treatment solution and then drying it. The silane coupling agent treatment solution contains γ-aminopropyltriethoxysilane. In the resin matrix phase, the components, by weight, are as follows: 50 parts of bisphenol A type epoxy resin, 20 parts of alicyclic epoxy resin, 3 parts of latent curing agent, 0.5 parts of accelerator, 5 parts of toughening agent, and 10 parts of inorganic thermally conductive filler.

[0030] Example 2: A method for preparing a rapidly curable epoxy resin-based glass fiber composite material, comprising the following steps: Step 1: Pretreatment of glass fiber fabric. Immerse the glass fiber fabric in a silane coupling agent treatment solution and treat it at 50°C for 20 minutes. After taking it out, dry it at 90°C for 1 hour to obtain the pretreated glass fiber fabric. Step 2: Preparation of rapid curing resin system. Bisphenol A type epoxy resin, alicyclic epoxy resin, latent curing agent, accelerator, toughening agent and inorganic thermally conductive filler are added to a vacuum stirring and dispersing device and stirred and mixed at 32℃ and 300 rpm for 22 minutes. Then, the vacuum is drawn to -0.09MPa and maintained for 7.5 minutes to remove air bubbles, and the rapid curing resin system is obtained. Step 3: Impregnation and pre-curing. The pretreated glass fiber fabric obtained in Step 1 is passed through a coating device to fully impregnate it with the fast-curing resin system obtained in Step 2, with the resin content controlled at 40%. The impregnated glass fiber fabric is then passed through a drying tunnel at 70°C for 2 minutes for pre-curing treatment to obtain the prepreg. Step 4: Laying up and molding. Lay up the multi-layer prepreg obtained in Step 3 in the preset direction and place it into the mold cavity preheated to 90°C. After closing the mold, apply a pressure of 10MPa and keep it at 130°C for 12 minutes to cure. Then, heat it to 160°C for 30 minutes. Step 5: Demolding and post-treatment. After the pressure holding is completed, cool to below 60°C, demold to obtain composite material blank, and then place the blank in an oven at 150°C for 1.5 hours of post-curing treatment to obtain a rapidly curable epoxy resin-based glass fiber composite material. In step two, the rapid-curing resin system comprises the following components by weight: 60 parts of bisphenol A epoxy resin, 25 parts of alicyclic epoxy resin, 5 parts of latent curing agent, 1.2 parts of accelerator, 10 parts of toughening agent, and 17 parts of inorganic thermally conductive filler.

[0031] In step one, the silane coupling agent treatment solution is prepared by the following method: Mix γ-aminopropyltriethoxysilane, ethanol and deionized water in a volume ratio of 1:8:1, adjust the pH to 5.0 with acetic acid, and use after stirring and aging at room temperature for 13 hours.

[0032] In step two, the alicyclic epoxy resin is 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, and the latent curing agent is dicyandiamide.

[0033] In step two, the accelerator is 2-methylimidazole and the toughening agent is carboxyl-terminated nitrile rubber.

[0034] In step two, the inorganic thermally conductive filler is spherical alumina surface-treated with silane coupling agent, with an average particle size D50 of 5 micrometers.

[0035] In step three, a rapid-curing resin system is coated onto both sides of the fiberglass fabric using a scraping method. The resin content of the fiberglass fabric is controlled to be 40% by adjusting process parameters, and the resin coating amount per unit area is 275 g / m². When using a scraper coating method, the gap between the scraper and the bearing surface should be controlled at 0.17mm.

[0036] In step four, the layup method is unidirectional layup, and the preheating temperature of the mold cavity is 90℃.

[0037] In step four, during the heat preservation and pressure curing process at 130℃, the temperature rise rate of the mold is 4℃ / minute. The heating rate from 130℃ to 160℃ is 2.5℃ / minute.

[0038] In step five, cooling involves circulating water at 25°C into the cooling channel of the mold while maintaining pressure, cooling it to below 60°C at a rate of 7°C / minute.

[0039] The composite material includes a reinforcing phase and a resin matrix phase. The reinforcing phase is a glass fiber fabric surface-treated with a silane coupling agent. The resin matrix phase consists of bisphenol A type epoxy resin, alicyclic epoxy resin, latent curing agent, accelerator, toughening agent and inorganic thermally conductive filler. The silane coupling agent surface treatment is achieved by immersing the glass fiber fabric in a silane coupling agent treatment solution and then drying it. The silane coupling agent treatment solution contains γ-aminopropyltriethoxysilane. In the resin matrix phase, the components, by weight, are as follows: The mixture contains 60 parts of bisphenol A type epoxy resin, 25 parts of alicyclic epoxy resin, 5 parts of latent curing agent, 1.2 parts of accelerator, 10 parts of toughening agent, and 17 parts of inorganic thermally conductive filler.

[0040] Example 3: A method for preparing a rapidly curable epoxy resin-based glass fiber composite material, comprising the following steps: Step 1: Pretreatment of glass fiber fabric. Immerse the glass fiber fabric in a silane coupling agent treatment solution and treat it at 60°C for 30 minutes. After taking it out, dry it at 100°C for 1.5 hours to obtain the pretreated glass fiber fabric. Step 2: Preparation of rapid curing resin system. Bisphenol A type epoxy resin, alicyclic epoxy resin, latent curing agent, accelerator, toughening agent and inorganic thermally conductive filler are added to a vacuum stirring and dispersing device and stirred and mixed at 40℃ and 400 rpm for 30 minutes. Then, the vacuum is drawn to -0.1MPa and maintained for 10 minutes to remove air bubbles, thus obtaining the rapid curing resin system. Step 3: Impregnation and pre-curing. The pretreated glass fiber fabric obtained in Step 1 is passed through a coating device to fully impregnate it with the fast-curing resin system obtained in Step 2, with the resin content controlled at 45%. The impregnated glass fiber fabric is then passed through an 80°C drying tunnel for 3 minutes of pre-curing treatment to obtain the prepreg. Step 4: Laying up and molding. Lay up the multi-layer prepreg obtained in Step 3 in the preset direction and put it into the mold cavity preheated to 100°C. After closing the mold, apply a pressure of 15MPa and keep it at 140°C for 15 minutes to cure. Then, heat it to 170°C for 40 minutes. Step 5: Demolding and post-treatment. After the pressure holding is completed, cool to below 60°C, demold to obtain composite material blank, and then place the blank in an oven at 160°C for 2 hours of post-curing treatment to obtain a rapidly curable epoxy resin-based glass fiber composite material. In step two, the rapid-curing resin system comprises the following components by weight: 70 parts of bisphenol A type epoxy resin, 30 parts of alicyclic epoxy resin, 8 parts of latent curing agent, 2 parts of accelerator, 15 parts of toughening agent, and 25 parts of inorganic thermally conductive filler.

[0041] In step one, the silane coupling agent treatment solution is prepared by the following method: Mix γ-aminopropyltriethoxysilane, ethanol and deionized water in a volume ratio of 1:8:1, adjust the pH to 5.5 with acetic acid, and use after stirring and aging at room temperature for 24 hours.

[0042] In step two, the alicyclic epoxy resin is 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, and the latent curing agent is dicyandiamide.

[0043] In step two, the accelerators are 2-methylimidazole and 2-ethyl-4-methylimidazole, and the toughening agent is carboxyl-terminated nitrile rubber.

[0044] In step two, the inorganic thermally conductive filler is spherical alumina surface-treated with silane coupling agent, with an average particle size D50 of 10 micrometers.

[0045] In step three, a slot coating method is used to coat both sides of the fiberglass fabric with a fast-curing resin system. The resin content of the fiberglass fabric is controlled to be 45% by adjusting process parameters, and the resin coating amount per unit area is 350 g / m². When using slit coating, the slit width of the coating head is controlled at 0.25 mm, and the delivery pressure of the metering pump is 0.6 MPa.

[0046] In step four, the layup method is unidirectional layup, and the preheating temperature of the mold cavity is 95℃.

[0047] In step four, during the heat preservation and pressure curing process at 140℃, the temperature rise rate of the mold is 5℃ / minute. The heating rate from 140℃ to 170℃ is 3℃ / minute.

[0048] In step five, cooling involves circulating water at 30°C into the cooling channel of the mold while maintaining pressure, cooling it to below 60°C at a rate of 10°C / minute.

[0049] The composite material includes a reinforcing phase and a resin matrix phase. The reinforcing phase is a glass fiber fabric surface-treated with a silane coupling agent. The resin matrix phase consists of bisphenol A type epoxy resin, alicyclic epoxy resin, latent curing agent, accelerator, toughening agent and inorganic thermally conductive filler. The silane coupling agent surface treatment is achieved by immersing the glass fiber fabric in a silane coupling agent treatment solution and then drying it. The silane coupling agent treatment solution contains γ-aminopropyltriethoxysilane. In the resin matrix phase, the components, by weight, are as follows: 70 parts of bisphenol A type epoxy resin, 30 parts of alicyclic epoxy resin, 8 parts of latent curing agent, 2 parts of accelerator, 15 parts of toughening agent, and 25 parts of inorganic thermally conductive filler.

[0050] Comparative Example 1: The difference between this comparative example and Examples 1-3 is that no toughening agent was added when preparing the rapid curing resin system in this comparative example.

[0051] Comparative Example 2 differs from Examples 1-3 in that no inorganic thermally conductive filler was added when preparing the rapid-curing resin system in this comparative example.

[0052] Comparative Example 3 differs from Examples 1-3 in that the glass fiber fabric was not pretreated with a silane coupling agent in this comparative example.

[0053] Comparative Example 4 differs from Examples 1-3 in that: in preparing the rapid-curing resin system, no alicyclic epoxy resin was added, and only bisphenol A type epoxy resin was used.

[0054] The performance of the rapidly curable epoxy resin-based glass fiber composite materials prepared in Examples 1-3 and Comparative Examples 1-4 was tested. The test items and test methods are as follows: Bending strength test: The bending strength is calculated using a universal testing machine.

[0055] Heat distortion temperature test: The heat distortion temperature was determined under a bending stress of 1.80 MPa.

[0056] Thermal conductivity test: The thermal conductivity was tested using a heat flow thermal conductivity meter.

[0057] Curing time test: Differential scanning calorimetry was used to record the time required for the resin system to reach the peak curing time from the start under a specified temperature program, such as 10°C / min, in order to evaluate the curing speed.

[0058] The test data of the rapidly curable epoxy resin-based glass fiber composites prepared in Examples 1-3 and Comparative Examples 1-4 are recorded in the table below: By comparing and analyzing the data in the table, it can be seen that the rapidly curable epoxy resin-based glass fiber composite materials prepared using the processes in Examples 1-3 have superior comprehensive performance compared to the rapidly curable epoxy resin-based glass fiber composite materials prepared using the processes in Comparative Examples 1-4. This indicates that the present invention, by using a rapidly curing resin system containing specific epoxy resin, latent curing agent, and accelerator, reduces the activation energy of the curing reaction and accelerates the curing reaction rate of the resin system, thereby achieving rapid molding of the composite material and improving production efficiency. Pretreatment of the glass fiber fabric with a silane coupling agent enhances the interfacial bonding force between the glass fiber and the epoxy resin matrix. The addition of a toughening agent to the resin system improves the toughness of the cured product. The synergistic effect of these two factors ensures that the composite material ultimately achieves high mechanical strength. By compounding inorganic thermally conductive fillers into the rapidly curing resin system, the thermal conductivity of the composite material is improved while achieving rapid curing. The resin system and curing process involved can maintain excellent heat resistance of the composite material while improving curing speed and thermal conductivity.

[0059] By comparing and analyzing the relevant data in the table, it can be seen that the epoxy resin-based glass fiber composite material prepared by the molding process of this invention has high mechanical strength, good heat resistance, improved thermal conductivity and rapid curing characteristics.

[0060] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0061] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a rapidly curable epoxy resin-based glass fiber composite material, characterized in that: Includes the following steps: Step 1: Pretreatment of glass fiber fabric. Immerse the glass fiber fabric in a silane coupling agent treatment solution and treat it at 40-60℃ for 10-30 minutes. After taking it out, dry it at 80-100℃ for 0.5-1.5 hours to obtain the pretreated glass fiber fabric. Step 2: Preparation of the rapid curing resin system. Bisphenol A type epoxy resin, alicyclic epoxy resin, latent curing agent, accelerator, toughening agent and inorganic thermally conductive filler are added to a vacuum stirring and dispersing device. The mixture is stirred and mixed at 25-40℃ and 200-400 rpm for 15-30 minutes. Then, the vacuum is drawn to -0.08 to -0.1 MPa and held for 5-10 minutes to remove air bubbles, thus obtaining the rapid curing resin system. Step 3: Impregnation and pre-curing. The pretreated glass fiber fabric obtained in Step 1 is passed through an impregnation tank or coating equipment to be fully impregnated with the fast-curing resin system obtained in Step 2. The resin content is controlled at 35%-45%. The impregnated glass fiber fabric is then passed through an oven at 60-80℃ for 1-3 minutes for pre-curing treatment to obtain the prepreg. Step 4: Laying up and molding. Lay up the multi-layer prepreg obtained in Step 3 in the preset direction and place it into the mold cavity preheated to 80-100℃. After closing the mold, apply a pressure of 5-15MPa and keep it at 120-140℃ for 8-15 minutes for heat preservation and pressure curing. Then, raise the temperature to 150-170℃ for post-treatment for 20-40 minutes. Step 5: Demolding and post-treatment. After the pressure holding is completed, cool to below 60°C, demold to obtain composite material blank, and then place the blank in an oven at 140-160°C for 1-2 hours of post-curing treatment to obtain the rapidly curable epoxy resin-based glass fiber composite material. In step two, the rapid-curing resin system comprises the following components by weight: 50-70 parts of bisphenol A epoxy resin, 20-30 parts of alicyclic epoxy resin, 3-8 parts of latent curing agent, 0.5-2 parts of accelerator, 5-15 parts of toughening agent, and 10-25 parts of inorganic thermally conductive filler.

2. The method for preparing a rapidly curable epoxy resin-based glass fiber composite material according to claim 1, characterized in that: In step one, the silane coupling agent treatment solution is prepared by the following method: Mix γ-aminopropyltriethoxysilane, ethanol and deionized water in a volume ratio of 1:8:1, adjust the pH to 4.5-5.5 with acetic acid, and use after stirring and aging at room temperature for 2-24 hours.

3. The method for preparing a rapidly curable epoxy resin-based glass fiber composite material according to claim 1, characterized in that: In step two, the alicyclic epoxy resin is 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate or vinyl cyclohexene dioxide, and the latent curing agent is at least one of dicyandiamide, adipate dihydrazide or boron trifluoride-monoethylamine complex.

4. The method for preparing a rapidly curable epoxy resin-based glass fiber composite material according to claim 1, characterized in that: In step two, the accelerator is at least one of 2-methylimidazole, 2-ethyl-4-methylimidazole, or 1-cyanoethyl-2-ethyl-4-methylimidazole, and the toughening agent is at least one of carboxyl-terminated butadiene-acrylonitrile rubber, polyurethane-modified epoxy resin, or core-shell structured rubber particles.

5. The method for preparing a rapidly curable epoxy resin-based glass fiber composite material according to claim 1, characterized in that: In step two, the inorganic thermally conductive filler is at least one of spherical alumina, aluminum nitride, or boron nitride that has been surface-treated with a silane coupling agent, and its average particle size D50 is 1-10 micrometers.

6. The method for preparing a rapidly curable epoxy resin-based glass fiber composite material according to claim 1, characterized in that: In step three, the rapid-curing resin system is coated onto both sides of the fiberglass fabric using methods such as impregnation, blade coating, or slot coating. The resin content of the fiberglass fabric is controlled to be 35%-45% by adjusting process parameters, and the resin coating amount per unit area is 200-350 g / m². When using the dip-resin method, the linear speed ratio of the guide roller to the extrusion roller in the dip-resin tank should be controlled to be 1:1.1-1.3; When using a scraper coating method, the gap between the scraper and the bearing surface should be controlled to be 0.15-0.40 mm; When using slit coating, the slit width of the coating head should be controlled to be 0.10-0.25mm, and the delivery pressure of the metering pump should be 0.2-0.6MPa.

7. The method for preparing a rapidly curable epoxy resin-based glass fiber composite material according to claim 1, characterized in that: In step four, the layup method is any one of unidirectional layup, orthogonal layup, or quasi-isotropic layup, and the preheating temperature of the mold cavity is 90±5℃.

8. The method for preparing a rapidly curable epoxy resin-based glass fiber composite material according to claim 1, characterized in that: In step four, during the heat preservation and pressure curing process at 120-140℃, the temperature rise rate of the mold is 3-5℃ / minute. The heating rate from 120-140℃ to 150-170℃ is 2-3℃ / minute.

9. The method for preparing a rapidly curable epoxy resin-based glass fiber composite material according to claim 1, characterized in that: In step five, cooling involves circulating water at 20-30°C into the cooling channel of the mold while maintaining pressure, cooling it to below 60°C at a rate of 5-10°C / minute.

10. A rapidly curable epoxy resin-based glass fiber composite material, prepared by the method for preparing a rapidly curable epoxy resin-based glass fiber composite material according to any one of claims 1-9, characterized in that: The composite material comprises a reinforcing phase and a resin matrix phase. The reinforcing phase is a glass fiber fabric surface-treated with a silane coupling agent. The resin matrix phase is composed of bisphenol A type epoxy resin, alicyclic epoxy resin, latent curing agent, accelerator, toughening agent and inorganic thermally conductive filler. The surface treatment with the silane coupling agent is achieved by immersing the glass fiber fabric in a silane coupling agent treatment solution and then drying it. The silane coupling agent treatment solution contains γ-aminopropyltriethoxysilane. The components in the resin matrix phase, by weight, are as follows: 50-70 parts of bisphenol A type epoxy resin, 20-30 parts of alicyclic epoxy resin, 3-8 parts of latent curing agent, 0.5-2 parts of accelerator, 5-15 parts of toughening agent, and 10-25 parts of inorganic thermally conductive filler.

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