A method for manufacturing an impact-resistant fiber-reinforced composite sheet and an impact-resistant fiber-reinforced composite sheet

Abstract

The present disclosure relates to the technical field of fiber composite board, and particularly relates to a preparation method of an impact-resistant fiber-reinforced composite board and the impact-resistant fiber-reinforced composite board; the preparation method comprises the following steps: preparing a modified fiber cloth; preparing a hydrogenated bisphenol A epoxy resin modified compound to obtain a resin component; sequentially laying a plurality of modified fiber cloths to obtain a laminated structure; mixing the resin component with a curing agent component and stirring uniformly, and then pumping into the laminated structure; and then curing, polishing and trimming to obtain the impact-resistant fiber-reinforced composite board. The present disclosure provides a preparation method of the fiber-reinforced composite board which is simple in process and excellent in impact resistance.

Description

Technical Field

[0001] This disclosure relates to the field of fiber composite board technology, and in particular to a method for preparing an impact-resistant fiber-reinforced composite board and the impact-resistant fiber-reinforced composite board itself. Background Technology

[0002] Fiber-reinforced composite panels have been widely used in aerospace, transportation, electronics, and building materials due to their outstanding advantages such as high specific strength, light weight, excellent corrosion resistance, and high molding flexibility. With the expansion of application scenarios, especially in impact-load-bearing applications such as automotive crash protection components, rail transit interior trim, and wind turbine blade sheaths, increasingly higher requirements are being placed on the impact resistance of composite panels.

[0003] In existing technologies, the main methods for improving the impact resistance of fiber-reinforced composite panels focus on resin matrix modification (such as adding elastomers and nanoparticles) and fiber reinforcement selection (such as using high-performance fibers like carbon fiber and aramid fiber). However, excessive modification of the resin matrix can easily lead to a decrease in the rigidity and heat resistance of the composite panel, while the application of high-performance fibers significantly increases the manufacturing cost, limiting its large-scale promotion. Therefore, the development of a simple process for preparing fiber-reinforced composite panels with excellent impact resistance is an urgent technical problem to be solved in this field. Summary of the Invention

[0004] This disclosure provides a method for preparing an impact-resistant fiber-reinforced composite board and the impact-resistant fiber-reinforced composite board itself, in order to address the shortcomings of related technologies.

[0005] According to a first aspect of the present disclosure, a method for preparing an impact-resistant fiber-reinforced composite panel is provided, the method comprising the following steps:

[0006] Step 1: Prepare modified fiber cloth; the fiber cloth is selected from glass fiber cloth, carbon fiber cloth, quartz fiber cloth, basalt fiber cloth or polyimide fiber cloth;

[0007] Step 2: Prepare hydrogenated bisphenol A epoxy resin modified compound; and mix the hydrogenated bisphenol A epoxy resin modified compound and hydrogenated bisphenol A epoxy resin to obtain a resin component;

[0008] Step 3: Lay out multiple modified fiber cloths prepared in Step 1 in sequence; then lay out release cloth, flow guide net and vacuum bag film in sequence to obtain a laminated structure; then mix the resin component prepared in Step 2 with the curing agent component and stir evenly, and inject it into the laminated structure through a vacuum pump;

[0009] Step 4: After injection, cure at room temperature; then grind and trim the edges to obtain the impact-resistant fiber-reinforced composite board.

[0010] In one aspect of this disclosure, in step 1, the modified fiber cloth is selected from silane coupling agent modified quartz fiber cloth; the silane coupling agent modified quartz fiber cloth is prepared by the following steps:

[0011] Step 1-a: Provide quartz fiber cloth; immerse the quartz fiber cloth in an organic acid solution for activation;

[0012] Step 2-a: Add the activated quartz fiber cloth to the organic solution, then add the silane coupling agent, and heat under nitrogen protection and reflux to obtain the silane coupling agent modified quartz fiber cloth.

[0013] In one aspect of this disclosure, in step 1, the silane coupling agent modified quartz fiber cloth is selected from ADMS silane coupling agent modified quartz fiber cloth; the ADMS silane coupling agent modified quartz fiber cloth is prepared by the following steps:

[0014] Step 1-a1: Prepare a mixed solution of citric acid and oxalic acid; immerse the quartz fiber cloth in the mixed solution, heat to 55℃-65℃, and stir for 3-6 hours; after the reaction is completed, wash and dry to obtain the activated quartz fiber cloth;

[0015] Step 2-a2: Add the activated quartz fiber cloth to 3-5 times its weight of toluene, and then add 0.05-0.15 times its weight of ADMS silane coupling agent; under nitrogen protection, stir and react at 110℃-120℃ for 12-36h; after the reaction is completed, wash and dry to obtain the quartz fiber cloth modified with ADMS silane coupling agent.

[0016] In one aspect of this disclosure, in step 1, the hydrogenated bisphenol A epoxy resin modified compound has the structural formula shown in Formula I-1:

[0017]

[0018] R1, R2, and R3 are each independently selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C2-C30 alkynyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C3-30 cycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted 3-30 heterocyclic, or substituted or unsubstituted 5-30 heteroaryl.

[0019] In one aspect of the embodiments of this disclosure, preferably, R1, R2 and R3 are each independently selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C3-30 cycloalkyl or substituted or unsubstituted 3-30 membered heterocyclic groups.

[0020] In one aspect of the embodiments of this disclosure, preferably, R1, R2 and R3 are each independently selected from C1-C30 alkyl, C2-C30 alkenyl, C1-C30 alkoxy, C3-30 cycloalkyl or 3-30 membered heterocyclic groups.

[0021] In one aspect of the embodiments of this disclosure, preferably, R1, R2 and R3 are each independently selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C1-C30 alkoxy or substituted or unsubstituted C3-30 cycloalkyl.

[0022] In one aspect of the embodiments of this disclosure, preferably, R1, R2 and R3 are each independently selected from C1-C30 alkyl, C1-C30 alkoxy or C3-30 cycloalkyl.

[0023] In one aspect of the embodiments of this disclosure, preferably, R1, R2 and R3 are each independently selected from C1-C10 alkyl or C1-C10 alkoxy.

[0024] In one aspect of the embodiments of this disclosure, preferably, R1, R2 and R3 are each independently selected from C1-C10 alkyl groups.

[0025] In one aspect of this disclosure, in step 1, the hydrogenated bisphenol A epoxy resin modified compound has the structural formula shown in Formula I-2:

[0026] .

[0027] In one aspect of this disclosure, in step 1, the mass ratio of the hydrogenated bisphenol A epoxy resin modified compound having the structural formula shown in Formula I-2 to the hydrogenated bisphenol A epoxy resin is selected from 1:(2-6).

[0028] In one aspect of the embodiments of this disclosure, specifically, in step 1, the mass ratio of the hydrogenated bisphenol A epoxy resin modified compound having the structural formula shown in Formula I-2 to the hydrogenated bisphenol A epoxy resin is 1:5.

[0029] In one aspect of this disclosure, step 3 includes:

[0030] Step 3-1: The modified fiber cloths prepared in Step 1 are laid in the mold in a ±45° oblique layup order. The fiber directions of adjacent fiber cloths are arranged alternately at +45° and -45°. During the layup process, the modified fiber cloths are controlled to be flat and wrinkle-free, and the adjacent fiber cloths are tightly bonded together.

[0031] Step 3-2: Lay out a release cloth and a flow guide net sequentially on the modified fiber cloth after laying out. The release cloth covers the upper surface of the modified fiber cloth, and the flow guide net covers the upper surface of the release cloth. Then, use a vacuum bag film to completely cover the layered structure. The edge of the vacuum bag film is sealed to the edge of the mold with a sealing strip. A vacuum pump inlet, a resin pouring port, and an overflow port are provided on the vacuum bag film to form a laminated structure.

[0032] Step 3-3: Mix the resin component and curing agent component obtained in Step 2 at a mass ratio of 100:(25-35). Stir at room temperature for 2-10 minutes at a stirring rate of 200-300 rpm to obtain a mixture. Start the vacuum pump to evacuate the laminated structure and control the vacuum degree to 0.090-0.098 MPa. Connect the mixture to the resin pouring port through the injection tube, so that the mixture can evenly penetrate and wet the modified fiber cloth along the guide net under the vacuum negative pressure. Continue to inject until the mixture flows out stably from the overflow port of the laminated structure without any air bubbles. Stop the injection and keep the vacuum pump continuously evacuating for 20-40 minutes to remove residual air bubbles in the system.

[0033] In one aspect of this disclosure, the curing agent component comprises at least one of diethylenetriamine, triethylenetetramine, and 4,4'-diaminodicyclohexylmethane; this disclosure does not impose specific limitations on the selection of the curing agent.

[0034] In one aspect of this disclosure, the curing agent may also optionally contain an accelerator.

[0035] In one aspect of the embodiments of this disclosure, specifically, the curing agent component comprises a curing agent diethylenetriamine and an accelerator 2,4,6-tris(dimethylaminomethyl)phenol; the mass ratio of the diethylenetriamine and 2,4,6-tris(dimethylaminomethyl)phenol is selected from (10-15):1.

[0036] In one aspect of this disclosure, step 4 includes:

[0037] Step 4-1: After injection, maintain a vacuum state and cure at room temperature for 24-72 hours;

[0038] Step 4-2: After curing, remove the vacuum bag film, guide net and release cloth, and use mechanical grinding to remove the burrs, excess glue and surface defects on the edge of the composite board. During the grinding process, control the grinding depth to not exceed 0.2mm to ensure that the surface of the composite board is flat. Then, the composite board is dimensionally adjusted to finally obtain the impact-resistant fiber-reinforced composite board.

[0039] In one aspect of the embodiments of this disclosure, there is no specific limitation on the number of layers of the modified fiber cloth, which can be arbitrarily selected according to the required thickness.

[0040] According to a second aspect of the present disclosure, an impact-resistant fiber-reinforced composite board is provided, which is prepared by the aforementioned preparation method.

[0041] The technical solutions provided by the embodiments of this disclosure may include the following beneficial effects:

[0042] As can be seen from the above embodiments, this disclosure provides a simple process for preparing fiber-reinforced composite panels with excellent impact resistance.

[0043] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0044] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0045] Figure 1 This is a schematic diagram of the laminated structure and resin casting of the preparation method disclosed herein;

[0046] Figure 2 This is a schematic diagram of the epoxy group bonding of the quartz fiber cloth surface-treated with ADMS silane coupling agent and the hydrogenated bisphenol A epoxy resin prepared by the method disclosed herein. Detailed Implementation

[0047] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0048] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. The embodiments described herein are illustrative in nature and are used to provide a basic understanding of this application. The embodiments of this application should not be construed as limiting this application.

[0049] For the sake of brevity, this article only discloses a few specific numerical ranges. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, just as any upper limit can be combined with any other upper limit to form an unspecified range. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form an unspecified range.

[0050] In this document, 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 limitation, 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.

[0051] In this description, unless otherwise stated, "above" and "below" include the stated number.

[0052] Unless otherwise stated, the terms used in this disclosure have their common meanings as commonly understood by those skilled in the art. Unless otherwise stated, the values ​​of the parameters mentioned in this disclosure can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this disclosure).

[0053] The term "about" is used to describe and indicate small variations. When used in conjunction with an event or situation, the term may refer to examples in which the event or situation occurred precisely or in examples in which the event or situation occurred very approximately. For example, when used in conjunction with numerical values, the term may refer to a range of variation less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. Additionally, quantities, ratios, and other numerical values ​​are sometimes presented in range format herein. It should be understood that such range format is for convenience and brevity and should be interpreted flexibly to include not only numerical values ​​explicitly specified as range limits but also all individual numerical values ​​or subranges covered within the range, as if each numerical value and subrange were explicitly specified.

[0054] The list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms can mean any combination of the listed items. For example, if items A and B are listed, then the phrase "at least one of A and B" means only A; only B; or A and B. In another instance, if items A, B, and C are listed, then the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may contain a single component or multiple components. Item B may contain a single component or multiple components. Item C may contain a single component or multiple components.

[0055] In this disclosure, the term "alkyl" refers to an aliphatic hydrocarbon group, which can be straight-chain or branched. Branched refers to one or more lower alkyl groups, such as methyl, ethyl, or propyl, that link a linear alkyl chain. "Lower alkyl" refers to a group containing about 1 to about 6 carbon atoms in the chain, which can be straight-chain or branched.

[0056] In this disclosure, the term "alkenyl" refers to an aliphatic hydrocarbon group containing at least one carbon-carbon double bond, which can be straight-chain or branched. Branched refers to one or more lower alkyl groups, such as methyl, ethyl, or propyl, attached to a linear alkenyl chain. "Lower alkenyl" refers to a group containing about 2 to about 6 carbon atoms in the chain, which can be straight-chain or branched.

[0057] In this disclosure, the term "alkynyl" refers to an aliphatic hydrocarbon group containing at least one carbon-carbon triple bond, which can be straight-chain or branched. Branching refers to one or more lower alkyl groups, such as methyl, ethyl, or propyl, attached to a linear alkynyl chain. "Lower alkynyl" refers to a chain containing about 2 to about 6 carbon atoms, which can be straight-chain or branched. Non-limiting examples of alkynyl groups include ethynyl, propynyl, 2-butynyl, 3-methylbutynyl, n-pentynyl, and decynyl.

[0058] In this disclosure, the term "aryl" refers to an aromatic monocyclic or polycyclic ring system. An aryl group may optionally be substituted with one or more "cyclic substituents," which may be the same or different, as defined herein. Non-limiting examples of suitable aryl groups include phenyl and naphthyl.

[0059] In this disclosure, the term "heteroaryl" refers to an aromatic monocyclic or polycyclic ring system, wherein one or more ring atoms are elements other than carbon, such as nitrogen, oxygen, or sulfur, either individually or in combination, and preferably a heteroaryl contains about 5 to about 6 ring atoms. A "heteroaryl" may optionally be substituted by one or more "cyclic substituents," which may be the same or different, as defined herein. The prefixes azido, oxa, or thiado preceding the name of a heteroaryl root indicate that at least one nitrogen, oxygen, or sulfur atom is present as a ring atom, respectively. The nitrogen atom of a heteroaryl may optionally be oxidized to the corresponding N-oxide. Suitable, non-limiting examples of heteroaryl groups include pyridyl, pyrazinyl, furanyl, phenylthio, pyrimidinyl, isoxazolyl, isothiazolyl, oxazolyl, thiazolyl, pyrazolyl, furazanyl, pyrroleyl, pyrazolyl, triazolyl, 1,2,4-thiadiazolyl, pyrazinyl, pyridazinyl, quinoxalinyl, 2,3-diazanaphthyl, imidazo[1,2-a]pyridyl, imidazo[2,1-b]thiazolyl, benzofurazanyl, indoleyl, azaindoleyl, benzimidazolyl, benzothiopheneyl, quinolinyl, imidazolyl, thienopyridyl, quinazolinyl, thienopyrimidinyl, pyrrolopyridyl, imidazopyridyl, isoquinolinyl, benzoazaindoleyl, 1,2,4-triazinyl, benzothiazolyl, etc.

[0060] In this disclosure, the term "amino" refers to the -NR′R′′ group. The amino group may optionally be substituted. In an unsubstituted amino group, R′ and R′′ are hydrogen. In a substituted amino group, R′ and R′′ may each independently be, but not limited to, hydrogen, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, alkylcycloalkyl, alkylheterocycloalkyl, alkoxy, sulfonyl, alkenyl, alkanoyl, aryl, arylalkyl, or heteroaryl, provided that R′ and R′′ are not both hydrogen. In a substituted amino group, R′ and R′′ may cyclize to form a cyclic amino group, such as pyrrolidinyl or piperidinyl. Such cyclic amino groups may incorporate other heteroatoms, for example, to form piperazine or morpholine groups. Such cyclic amino groups may optionally be substituted, for example, by an amino, hydroxyl, or oxo group.

[0061] In this disclosure, the term "alkoxy" refers to -O-alkyl. Alkoxy can refer to a straight-chain, branched, or cyclic, saturated or unsaturated oxy-hydrocarbon chain, including, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, tert-butoxy, and pentoxy. Alkoxy may optionally be substituted by one or more alkoxy substituents ("substituted alkoxy").

[0062] In this disclosure, the term "cycloalkyl" refers to a non-aromatic mono- or polycyclic ring system, preferably containing about 5 to about 7 ring atoms. The cycloalkyl group may optionally be substituted with one or more "cyclic substituents," which may be the same or different, as defined above. Suitable monocyclic cycloalkyl groups, without limitation, include cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, etc. Suitable polycyclic cycloalkyl groups, without limitation, include 1-decahydronaphthyl, norcamphenyl, adamantyl, etc. In this disclosure, the term "cycloalkoxy" refers to a group in which one or more carbon atoms in the mono- or polycyclic ring system of the "cycloalkyl" group are substituted with oxygen atoms.

[0063] In this disclosure, the term "heterocyclic group" refers to a non-aromatic saturated monocyclic or polycyclic ring system, wherein one or more ring atoms in the ring system are elements other than carbon, such as nitrogen, oxygen, or sulfur, either individually or in combination. Adjacent oxygen and / or sulfur atoms are absent in the ring system, and preferred heterocycles contain about 5 to about 6 ring atoms. The prefixes aza, oxa, or thioa preceding the name of the heterocyclic group indicate that at least one nitrogen, oxygen, or sulfur atom is present as a ring atom, respectively. The heterocyclic group may optionally be substituted with one or more "cyclic substituents," which may be the same or different, as defined herein. The nitrogen or sulfur atom of the heterocyclic group may optionally be oxidized to the corresponding N-oxide, S-oxide, or S,S-dioxide. Non-limiting examples of suitable monocyclic heterocyclic rings include piperidinyl, pyrrolyl, piperazine, morpholinyl, thiomorpholinyl, thiazolyl, 1,3-dioxolanecycloyl, 1,4-dioxacyclohexyl, tetrahydrofuranyl, tetrahydrophenylthio, tetrahydrothiopyranyl, etc.

[0064] The present disclosure will be further described below by way of specific embodiments. Unless otherwise specified, all chemical reagents used in the embodiments of the present disclosure are obtained through conventional commercial means. Unless otherwise specified, all contents mentioned below are mass contents. Unless otherwise specified, it is understood that the process is carried out at room temperature.

[0065] Example

[0066] Example 1:

[0067] Example 1 includes the following steps:

[0068] 1. Preparation of modified fiber cloth:

[0069] Quartz fiber cloth (area density 200g / m²) 2 The quartz fiber cloth was cut into 15cm*15cm square shapes. Multiple cut quartz fiber cloths were immersed in a mixed solution of citric acid and oxalic acid (where the concentration of oxalic acid was 0.75mol / L and the concentration of citric acid was 0.15mol / L; there was no specific limit to the amount of mixed solution used, as long as the quartz fiber cloth was completely immersed). The temperature was raised to 60℃ and the reaction was stirred for 4 hours. After the reaction was completed, the cloth was washed (washed 3 times with deionized water) and dried to obtain activated quartz fiber cloth. The activated quartz fiber cloth was added to 5 times its weight of dry toluene, and then 0.1 times its weight of ADMS silane coupling agent was added. The cloth was stirred and reacted at 115℃ for 24 hours under nitrogen protection. After the reaction was completed, the cloth was washed (washed once with deionized water, once with acetone, once with ethanol, and finally once with deionized water) and dried to obtain quartz fiber cloth modified with ADMS silane coupling agent.

[0070] 2. Preparation of hydrogenated bisphenol A epoxy resin modified compounds:

[0071] Hydrogenated bisphenol A epoxy resin (DGEHBA, commercially available) was provided as the raw material. DGEHBA was vacuum dried to remove moisture. Then, N-(2-aminoethyl)-N'-octylethylenediamine was dried using a molecular sieve and collected under nitrogen protection. The raw materials were weighed according to a molar ratio of N-(2-aminoethyl)-N'-octylethylenediamine to DGEHBA of 1.2:1. Under nitrogen protection, N-(2-aminoethyl)-N'-octylethylenediamine was slowly added to DGEHBA in portions, with the reaction temperature controlled at 90°C and stirred at 250 rpm for 2 hours. Heating was then stopped, and the mixture was allowed to cool naturally to room temperature under nitrogen protection to obtain the modified hydrogenated bisphenol A epoxy resin compound. The reaction formula is shown below:

[0072]

[0073] 3. Preparation of impact-resistant fiber-reinforced composite panels:

[0074] The hydrogenated bisphenol A epoxy resin modified compound and hydrogenated bisphenol A epoxy resin (here, the hydrogenated bisphenol A epoxy resin and the raw material hydrogenated bisphenol A epoxy resin used to prepare the hydrogenated bisphenol A epoxy resin modified compound are the same product) were mixed at a mass ratio of 1:5. After mechanical stirring, a homogeneous resin mixture without stratification was obtained, which was used as the resin component of this embodiment. The curing agent component was diethylenetriamine and 2,4,6-tris(dimethylaminomethyl)phenol mixed at a weight ratio of 12:1, which was used as the curing agent component of this embodiment.

[0075] Thirteen layers of modified fiber cloth were sequentially laid in the mold in a ±45° oblique layup sequence. The fiber directions of adjacent layers were alternately arranged at +45° and -45°, respectively. During the layup process, the modified fiber cloth was kept flat and wrinkle-free, and the adjacent fiber cloths were tightly bonded together. A release cloth and a flow guide net were then sequentially laid on top of the modified fiber cloth. The release cloth completely covered the upper surface of the modified fiber cloth, and the flow guide net completely covered the upper surface of the release cloth. A vacuum bag film was then used to completely enclose the layup structure. The edges of the vacuum bag film were sealed to the mold edges with sealing strips. A vacuum pump inlet, resin pouring port, and overflow port were provided on the vacuum bag film to form a laminated structure. See details below. Figure 1 As shown ( Figure 1 (The overflow port is not shown in the diagram). The resin component and the curing agent component are mixed at a mass ratio of 100:30 and stirred at 200 rpm for 5 minutes at room temperature to obtain a mixture. The vacuum pump is started to evacuate the laminated structure of this embodiment, and the vacuum degree is controlled to be about 0.095 MPa. The mixture is connected to the resin pouring port through the injection tube, so that the mixture can be evenly penetrated along the guide net and impregnated with the modified fiber cloth under the action of vacuum negative pressure. The injection is continued until the mixture flows out stably from the overflow port of the laminated structure without any air bubbles. The injection is stopped, and the vacuum pump is kept in vacuum for 25 minutes to remove residual air bubbles in the system. After the injection is completed, the vacuum state is maintained and cured at room temperature for 48 hours. After the curing is completed, the vacuum bag film, guide net and release cloth are removed. The burrs, overflow and surface defects of the composite board are removed by mechanical grinding. During the grinding process, the grinding depth is controlled not to exceed 0.2 mm to ensure that the surface of the composite board is flat. Then the composite board is dimensionally trimmed to finally obtain the impact-resistant fiber-reinforced composite board of this embodiment.

[0076] Comparative Example 1:

[0077] The steps of Comparative Example 1 are the same as those of Example 1, except that Comparative Example 1 does not include the process of modifying the quartz fiber cloth, but instead the quartz fiber cloth is washed, dried and then directly laminated.

[0078] Example 2:

[0079] The steps in Example 2 are the same as in Example 1, except that in Example 2, the quartz fiber cloth is replaced with glass fiber cloth of approximately the same thickness (3k filament bundle, 200g / m²). 2 ).

[0080] Comparative Example 2:

[0081] The steps of Comparative Example 2 are the same as those of Example 2, except that Comparative Example 2 does not include the process of modifying the glass fiber cloth, but instead the glass fiber cloth is washed, dried and then directly laminated.

[0082] Example 3:

[0083] The steps in Example 3 are the same as in Example 1, except that Example 3 uses an equal mass of silane coupling agent KH-560 instead of ADMS silane coupling agent.

[0084] Example 4:

[0085] The steps in Example 4 are the same as in Example 1, except that Example 4 uses an equal mass of silane coupling agent KH-570 instead of ADMS silane coupling agent.

[0086] Comparative Example 3:

[0087] Comparative Example 3 includes the following steps:

[0088] 1. Preparation of modified fiber cloth:

[0089] Quartz fiber cloth (area density 200g / m²) 2 The quartz fiber cloth was cut into 15cm*15cm square shapes. Multiple cut quartz fiber cloths were immersed in a mixed solution of citric acid and oxalic acid (where the concentration of oxalic acid was 0.75mol / L and the concentration of citric acid was 0.15mol / L; there was no specific limit to the amount of mixed solution used, as long as the quartz fiber cloth was completely immersed). The temperature was raised to 60℃ and the reaction was stirred for 4 hours. After the reaction was completed, the cloth was washed (washed 3 times with deionized water) and dried to obtain activated quartz fiber cloth. The activated quartz fiber cloth was added to 5 times its weight of dry toluene, and then 0.1 times its weight of ADMS silane coupling agent was added. The cloth was stirred and reacted at 115℃ for 24 hours under nitrogen protection. After the reaction was completed, the cloth was washed (washed once with deionized water, once with acetone, once with ethanol, and finally once with deionized water) and dried to obtain quartz fiber cloth modified with ADMS silane coupling agent.

[0090] 2. Preparation of impact-resistant fiber-reinforced composite panels:

[0091] Hydrogenated bisphenol A epoxy resin was used as the resin component of this comparative example; the curing agent component was a mixture of diethylenetriamine and 2,4,6-tris(dimethylaminomethyl)phenol in a weight ratio of 12:1.

[0092] Thirteen layers of modified fiber cloth were laid in the mold in a ±45° oblique layup sequence, with the fiber directions of adjacent layers alternating at +45° and -45° respectively. During the layup process, the modified fiber cloth was kept flat and wrinkle-free, and the adjacent fiber cloths were tightly bonded together. A release cloth and a flow guide net were then laid on the modified fiber cloth. The release cloth completely covered the upper surface of the modified fiber cloth, and the flow guide net completely covered the upper surface of the release cloth. Then, a vacuum bag film was used to completely cover the layup structure. The edges of the vacuum bag film were sealed to the edges of the mold with sealing strips. A vacuum pump inlet, a resin pouring port, and an overflow port were provided on the vacuum bag film to form a laminated structure. The resin component and curing agent component were mixed at a mass ratio of 100:30 and stirred at 200 rpm for 5 minutes at room temperature to obtain a mixture. A vacuum pump was started to evacuate the laminated structure of this embodiment, controlling the vacuum level to approximately 0.095 MPa. The mixture was connected to the resin pouring port through a dispensing tube, allowing it to uniformly penetrate and impregnate the modified fiber cloth under vacuum pressure along the guide net. Injection continued until the mixture flowed steadily from the overflow port of the laminated structure without any air bubbles. Injection was stopped, and the vacuum pump was maintained for 25 minutes to remove residual air bubbles from the system. After injection, the system was cured at room temperature under vacuum for 48 hours. After curing, the vacuum bag, guide net, and release cloth were removed. Mechanical grinding was used to remove burrs, excess glue, and surface defects from the edges of the composite board. During grinding, the grinding depth was controlled to not exceed 0.2 mm to ensure a smooth surface. The composite board was then dimensionally adjusted to obtain the impact-resistant fiber-reinforced composite board of this comparative example.

[0093] The difference between Comparative Example 3 and Example 1 is that Comparative Example 3 does not include the steps of preparing the hydrogenated bisphenol A epoxy resin modified compound and using the hydrogenated bisphenol A epoxy resin modified compound as a resin component.

[0094] Example 5:

[0095] Example 5 includes the following steps:

[0096] Preparation of the hydrogenated bisphenol A epoxy resin modified compound of Example 5:

[0097] Hydrogenated bisphenol A epoxy resin (DGEHBA, commercially available) was provided as raw material. DGEHBA was vacuum dried to remove moisture. Tris(2-aminoethyl)amine was then dried and used under nitrogen protection. The raw materials were weighed according to a molar ratio of 1.2:1 for tris(2-aminoethyl)amine and DGEHBA. Under nitrogen protection, tris(2-aminoethyl)amine was slowly added to DGEHBA in batches, with the reaction temperature controlled at 90°C and stirred at 250 rpm for 2 hours. Heating was then stopped, and the mixture was allowed to cool naturally to room temperature under nitrogen protection to obtain the hydrogenated bisphenol A epoxy resin modified compound of Example 5. The prepared hydrogenated bisphenol A epoxy resin modified compound and hydrogenated bisphenol A epoxy resin were mixed at a mass ratio of 1:5. After mechanical stirring, the resulting resin components showed stratification. Therefore, the hydrogenated bisphenol A epoxy resin modified compound prepared in Example 5 cannot be used as a partial raw material for preparing composite boards using the preparation method disclosed herein.

[0098] Example 6:

[0099] Example 6 includes the following steps:

[0100] Preparation of the hydrogenated bisphenol A epoxy resin modified compound of Example 6:

[0101] Hydrogenated bisphenol A epoxy resin (DGEHBA, commercially available) was provided as raw material. DGEHBA was vacuum dried to remove moisture. Then, laurylamine was dried and used under nitrogen protection. The raw materials were weighed according to a molar ratio of laurylamine to DGEHBA of 1.2:1. Under nitrogen protection, laurylamine was slowly added to DGEHBA in batches, controlling the reaction temperature at 90°C and stirring at 250 rpm for 2 hours. Heating was then stopped, and the mixture was allowed to cool naturally to room temperature under nitrogen protection to obtain the hydrogenated bisphenol A epoxy resin modified compound of Example 6. The prepared hydrogenated bisphenol A epoxy resin modified compound and hydrogenated bisphenol A epoxy resin were mixed at a mass ratio of 1:5. After mechanical stirring, the resulting resin component was found to be turbid. Therefore, the hydrogenated bisphenol A epoxy resin modified compound prepared in Example 6 cannot be used as a partial raw material for preparing composite boards using the preparation method of this disclosure.

[0102] Mechanical property testing:

[0103] Impact strength test: The impact strength of Examples 1-4 and Comparative Examples 1-3 were tested according to standard GB / T1449-2005, and the results are shown in Table 1.

[0104] Bending strength test: The bending strength of Examples 1-4 and Comparative Examples 1-3 were tested according to standard GB / T2567-2021, and the results are shown in Table 1.

[0105] Table 1

[0106] Example <![CDATA[Impact strength (kJ / m 2 )]]> Bending strength (MPa) Example 1 60.9 141 Comparative Example 1 42.8 132 Example 2 46.3 133 Comparative Example 2 49.5 137 Example 3 45.0 135 Example 4 47.2 137 Comparative Example 3 38.4 126

[0107] As can be seen, compared to Examples 2-4 and Comparative Examples 1-2, Example 1 exhibits better impact resistance. This is because the surface of the quartz fiber cloth treated with ADMS silane coupling agent has segments grafted with NH2 end groups, which can form bonds with the epoxy groups of hydrogenated bisphenol A epoxy resin (e.g., Figure 2 As shown in the figure, it can significantly improve impact resistance, while the use of coupling agents such as KH560 and KH570 with non-amino end groups does not significantly improve the effect.

[0108] Compared to Comparative Example 3, Example 1 exhibits better impact resistance. This is because the hydrogenated bisphenol A epoxy resin modified compound prepared in Example 2 has the following advantages: (1) The hydrogenated bisphenol A epoxy resin modified compound prepared by N-(2-aminoethyl)-N'-octylethylenediamine and DGEHBA has long-chain octyl (C8) flexible branches, which breaks the rigid and regular structure of the original DGEHBA molecular chain; the long-chain alkyl has good chain segment mobility. When subjected to impact load, the flexible branches can bend and slip, dissipating a large amount of impact energy through the movement of the molecular chain, thus avoiding the epoxy resin from being too rigid. (2) The hydrogenated bisphenol A epoxy resin modified compound prepared by N-(2-aminoethyl)-N'-octylethylenediamine and DGEHBA has good compatibility with hydrogenated bisphenol A epoxy resin and can be directly mixed with hydrogenated bisphenol A epoxy resin as the resin component of this disclosure (the products prepared in Examples 4-5 cannot achieve this); (3) The side chains of the hydrogenated bisphenol A epoxy resin modified compound prepared by N-(2-aminoethyl)-N'-octylethylenediamine and DGEHBA also have -NH- groups, which can improve its wettability on the surface of quartz fiber cloth to a certain extent.

[0109] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein.

Claims

1. A method for preparing an impact-resistant fiber-reinforced composite board, characterized in that, The preparation method includes the following steps: Step 1: Prepare modified fiber cloth; the fiber cloth is selected from glass fiber cloth, carbon fiber cloth, quartz fiber cloth, basalt fiber cloth or polyimide fiber cloth; Step 2: Prepare hydrogenated bisphenol A epoxy resin modified compound; and mix the hydrogenated bisphenol A epoxy resin modified compound and hydrogenated bisphenol A epoxy resin to obtain a resin component; Step 3: Lay out multiple modified fiber cloths prepared in Step 1 in sequence; then lay out release cloth, flow guide net and vacuum bag film in sequence to obtain a laminated structure; then mix the resin component prepared in Step 2 with the curing agent component and stir evenly, and inject it into the laminated structure through a vacuum pump; Step 4: After injection, cure at room temperature; then, after grinding and trimming, the impact-resistant fiber-reinforced composite board is obtained. In step 1, the hydrogenated bisphenol A epoxy resin modified compound has the structural formula shown in Formula I-2: In step 1, the mass ratio of the hydrogenated bisphenol A epoxy resin modified compound having the structure shown in Formula I-2 to the hydrogenated bisphenol A epoxy resin is selected from 1:(2-6).

2. The method for preparing the impact-resistant fiber-reinforced composite board according to claim 1, characterized in that, In step 1, the modified fiber cloth is selected from quartz fiber cloth modified with a silane coupling agent; the quartz fiber cloth modified with a silane coupling agent is prepared through the following steps: Step 1-a: Provide quartz fiber cloth; immerse the quartz fiber cloth in an organic acid solution for activation; Step 2-a: Add the activated quartz fiber cloth to the organic solution, then add the silane coupling agent, and heat under nitrogen protection and reflux. The silane coupling agent-modified quartz fiber cloth was obtained.

3. The method for preparing the impact-resistant fiber-reinforced composite board according to claim 2, characterized in that, In step 1, the silane coupling agent modified quartz fiber cloth is selected from ADMS silane coupling agent modified quartz fiber cloth; the ADMS silane coupling agent modified quartz fiber cloth is prepared through the following steps: Step 1-a1: Prepare a mixed solution of citric acid and oxalic acid; immerse the quartz fiber cloth in the mixed solution, heat to 55℃-65℃, and stir for 3-6 hours; after the reaction is completed, wash and dry to obtain the activated quartz fiber cloth; Step 2-a2: Add the activated quartz fiber cloth to 3-5 times its weight of toluene, and then add 0.05-0.15 times its weight of ADMS silane coupling agent; under nitrogen protection, stir and react at 110℃-120℃ for 12-36h; after the reaction is completed, wash and dry to obtain the quartz fiber cloth modified with ADMS silane coupling agent.

4. The method for preparing the impact-resistant fiber-reinforced composite board according to claim 1, characterized in that, Step 3 includes: Step 3-1: The modified fiber cloths prepared in Step 1 are laid in the mold in a ±45° oblique layup order. The fiber directions of adjacent fiber cloths are arranged alternately at +45° and -45°. During the layup process, the modified fiber cloths are controlled to be flat and wrinkle-free, and the adjacent fiber cloths are tightly bonded together. Step 3-2: Lay out a release cloth and a flow guide net sequentially on the modified fiber cloth after laying out. The release cloth covers the upper surface of the modified fiber cloth, and the flow guide net covers the upper surface of the release cloth. Then, use a vacuum bag film to completely cover the layered structure. The edge of the vacuum bag film is sealed to the edge of the mold with a sealing strip. A vacuum pump inlet, a resin pouring port, and an overflow port are provided on the vacuum bag film to form a laminated structure. Step 3-3: Mix the resin component and curing agent component obtained in Step 2 at a mass ratio of 100:(25-35). Stir at room temperature for 2-10 minutes at a stirring rate of 200-300 rpm to obtain a mixture. Start the vacuum pump to evacuate the laminated structure and control the vacuum degree to 0.090-0.098 MPa. Connect the mixture to the resin pouring port through the injection tube, so that the mixture can evenly penetrate and wet the modified fiber cloth along the guide net under the vacuum negative pressure. Continue to inject until the mixture flows out stably from the overflow port of the laminated structure without any air bubbles. Stop the injection and keep the vacuum pump continuously evacuating for 20-40 minutes to remove residual air bubbles in the system.

5. The method for preparing the impact-resistant fiber-reinforced composite board according to claim 1, characterized in that, Step 4 includes: Step 4-1: After injection, maintain a vacuum state and cure at room temperature for 24-72 hours; Step 4-2: After curing, remove the vacuum bag film, guide net and release cloth, and use mechanical grinding to remove the burrs, excess glue and surface defects on the edge of the composite board. During the grinding process, control the grinding depth to not exceed 0.2mm to ensure that the surface of the composite board is flat. Then, the composite board is dimensionally adjusted to finally obtain the impact-resistant fiber-reinforced composite board.

6. An impact-resistant fiber-reinforced composite board, characterized in that, The impact-resistant fiber-reinforced composite board is prepared by the preparation method described in any one of claims 1-5.

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