Preparation method of fiber reinforced resin composite material and insulating pull rod

Abstract

The invention relates to a preparation method of a fiber reinforced resin composite material and an insulating pull rod, and belongs to the technical field of fiber resin composite materials. The preparation method of the fiber reinforced resin composite material comprises the following steps: stacking a plurality of layers of glass fiber woven cloth to obtain a stacked body; then, glass fibers are used as suture lines to conduct upper and lower layer penetrating suture in the thickness direction of the stacked body, and a suture body is obtained; stacking the plurality of suturing bodies to obtain a laminated suturing body; and finally, impregnating the laminated sewed body with resin, and curing to obtain the fiber reinforced resin composite material. According to the preparation method of the fiber reinforced resin composite material, the glass fiber yarns are used as the weaving lines, and the glass fiber cloth is subjected to three-dimensional weaving and then is impregnated with the resin and cured; the mechanical strength of the fiber reinforced resin composite material in the direction perpendicular to fibers, the bearing capacity to high-speed large impact loads, the fatigue resistance and the compression strength can be effectively improved.

Description

Technical Field

[0001] The present invention relates to a preparation method of a fiber-reinforced resin composite material and an insulating pull rod, belonging to the technical field of fiber resin composite materials. Background Technique

[0002] High-voltage switchgear is an important part of power transmission and transformation lines. The stability of switchgear and its core components is related to the stable operation of the entire power system. The insulating pull rod is one of the key components in high-voltage switchgear and bears extreme working conditions of high speed, high load, and high voltage during equipment operation. Therefore, by improving the processing technology of fiber-reinforced composite materials, the preparation of insulating pull rods with excellent mechanical properties and high insulation has become a current research hotspot.

[0003] Chinese patent document CN117457116A discloses a method for improving the comprehensive performance of fiber-reinforced composite materials based on gradient weaving density. The method disclosed in this patent document specifically includes the following steps: dividing the insulating pull rod based on the radial mechanical stress distribution of the epoxy resin insulating pull rod, selecting the weaving density of the fiber-reinforced composite material with the corresponding density according to the stress distribution of each region, and the size of the weaving density of each region is proportional to the mechanical stress intensity borne by each region. By regulating the weaving density of the composite material, the mechanical stress distribution of each region of the epoxy resin insulating pull rod under long-term operating conditions is optimized, so that the mechanical stress field of each region along the radial direction of the insulating pull rod changes from extremely uneven to uniform distribution, significantly improving the comprehensive performance of the epoxy resin insulating pull rod. However, in this patent document, fiber-reinforced composite materials with various mass fractions and fiber layers with different densities are used, the types of raw materials are numerous, the preparation method is cumbersome, and the processing difficulty and raw material cost are relatively high. Chinese patent document CN116515141A discloses a method for modifying aramid fibers for insulating pull rods based on dopamine secondary treatment. The method disclosed in this patent document specifically includes the following steps: cleaning and drying the aramid fibers for insulating pull rods; placing the aramid fibers in a dielectric barrier discharge plasma device for plasma modification treatment; soaking the aramid fibers in a dopamine solution for dopamine modification treatment; cleaning and drying the modified aramid fibers; performing vacuum pressure impregnation of the aramid fibers with epoxy resin; and performing high-temperature curing treatment on the aramid fiber insulating pull rod after vacuum pressure impregnation to obtain the finished product of the modified aramid fiber insulating pull rod. The method disclosed in this patent document has many processes, and the fiber bonding force is affected by the type of modification solution and the modification effect, and the processing cost is high.

[0004] At present, fiber composite resin-based insulating tie rods are generally prepared by stacking and laminating glass fiber cloths and impregnating them with epoxy resin under vacuum assistance. During the actual application of fiber-reinforced resin composites, loads act in both directions parallel and perpendicular to the fibers. Axial compressive forces parallel to the fibers can easily cause phenomena such as delamination, gaps, and cracks in the composites. And the insulating tie rods operate under high voltage and large impact loads for a long time. The long-term high-speed loads will expand the defects and fine cracks that appear in the tie rods, resulting in flashover and breakdown phenomena of the tie rods and abnormal operation of the equipment.

[0005] Therefore, there is an urgent need to provide a preparation method for fiber-reinforced resin composites for insulating tie rods that has a low processing cost and can improve the axial tolerance of fiber-reinforced resin composites. Summary of the Invention

[0006] The purpose of the present invention is to provide a preparation method for fiber-reinforced resin composites, which can solve the problem that the currently prepared fiber-reinforced resin composites have relatively low mechanical strength in the direction perpendicular to the fibers.

[0007] Another purpose of the present invention is to provide an insulating tie rod, which can solve the problem that flashover and breakdown are likely to occur when the currently fiber-reinforced resin composites are used for insulating tie rods.

[0008] In order to achieve the above purposes, the technical solution adopted by the preparation method of the fiber-reinforced resin composite material of the present invention is as follows:

[0009] A preparation method for a fiber-reinforced resin composite material includes the following steps: stacking a plurality of layers of glass fiber woven cloths to obtain a stacked body; then using glass fibers as suture threads to penetrate and suture the upper and lower layers along the thickness direction of the stacked body to obtain a sutured body; then stacking a plurality of sutured bodies to obtain a laminated sutured body; and finally impregnating the laminated sutured body with resin and curing it to obtain a fiber-reinforced resin composite material.

[0010] The preparation method of the fiber-reinforced resin composite material of the present invention uses glass fiber yarn as the braiding thread. After three-dimensional braiding of the glass fiber cloth, it is impregnated with resin and cured, which can effectively improve the mechanical strength of the fiber-reinforced resin composite material in the direction perpendicular to the fiber, the bearing capacity for high-speed large impact loads, the fatigue resistance and the compressive strength, effectively reduce defects such as looseness and cracks that occur after the insulating pull rod works for a long time, and further avoid phenomena such as flashover and breakdown rupture of the insulating pull rod. In the preparation method of the fiber-reinforced resin composite material of the present invention, the glass fibers inserted in the thickness direction of the fiber cloth improve the problem of excessive difference in axial and radial mechanical strengths of the fiber-reinforced composite material and the structural anisotropy. The mechanical strength of the composite material in the thickness direction is improved, and the application working conditions of the composite material are broadened. In the preparation method of the fiber-reinforced resin composite material of the present invention, z-direction glass fibers are introduced in the thickness direction of the fiber cloth, which improves the problem of excessive difference in mechanical strengths of the fiber-reinforced composite material in the parallel and perpendicular fiber directions and the structural anisotropy, so that the mechanical strength of the fiber-reinforced composite material is improved, and the application working conditions of the composite material are broadened.

[0011] Preferably, the thickness ratio of the stack and the stitched body is 1:(0.9 - 0.95).

[0012] Preferably, the mass fraction of the laminated stitched body in the fiber-reinforced resin composite material is 65 - 70%.

[0013] Preferably, during stitching, multiple groups of stitching lines are arranged at intervals along the width direction of the stack to form multiple stitching paths, and each stitching line is stitched along the length direction of the stack.

[0014] Preferably, the interval between the stitching paths is 20 - 40 mm, and the stitching interval of each stitching line is 5 - 10 mm.

[0015] Preferably, the number of layers of the glass fiber woven cloth in the stack is 10 - 30.

[0016] Preferably, the number of stacked stitched bodies in the laminated stitched body is 2 - 8. The number of layers of the woven body and the number of stacked stitched bodies should be determined according to the thickness of the product and the parameters and operating range of the processing equipment.

[0017] Preferably, the glass fiber woven cloth is a biaxial glass fiber woven cloth, and the single-layer thickness is 0.6 - 1 mm; the diameter of the stitching line is 0.3 - 0.8 mm.

[0018] Preferably, the resin is composed of an epoxy resin, a curing agent, and a curing accelerator; the curing process includes one-stage curing, two-stage curing, three-stage curing, and four-stage curing performed sequentially; the one-stage curing temperature is 70 - 80°C, and the time is 1 - 3h; the two-stage curing temperature is 80 - 100°C, and the time is 1 - 3h; the three-stage curing temperature is 110 - 120°C, and the time is 5 - 10h; the four-stage curing temperature is 120 - 130°C, and the time is 3 - 5h.

[0019] The technical solution adopted for the insulating pull rod of the present invention is as follows:

[0020] An insulating pull rod prepared by the preparation method of the fiber-reinforced resin composite material as described above.

[0021] The fiber-reinforced resin composite material of the present invention has good mechanical strength in the direction perpendicular to the fiber, load-bearing capacity for high-speed large impact loads, fatigue resistance, and compressive strength, and can be used for insulating pull rods of high-voltage switchgear to improve the service life of the insulating pull rods. Brief Description of the Drawings

[0022] Figure 1 It is a cross-sectional view of the suture body in Embodiment 1 of the present invention;

[0023] Figure 2 It is a top view of the suture body in Embodiment 1 of the present invention;

[0024] Figure 3 It is a schematic diagram of the compression molding die in Embodiment 1 of the present invention;

[0025] Figure 4 It is a schematic diagram of the biaxial fiberglass woven fabric in the comparative example of the present invention;

[0026] Figure 5 It is a side view of the stacked body in the comparative example of the present invention. Detailed Description of the Embodiments

[0027] The preparation method of the fiber-reinforced resin composite material of the present invention is a pioneering invention. Aiming at the problems that the fiber-reinforced resin composite material is subjected to axial compressive force parallel to the fiber direction during actual application, resulting in delamination, gaps, and cracks in the composite material, the present invention uses fiberglass yarn as the weaving thread, and after three-dimensional weaving of the fiberglass cloth, it is impregnated with epoxy resin to improve the mechanical strength, load-bearing capacity for high-speed large impact loads, fatigue resistance, and compressive strength of the fiber-reinforced resin composite material in the direction perpendicular to the fiber.

[0028] The following combines specific embodiments to detail the technical solutions of the present invention.

[0029] I. The specific embodiments of the preparation method of the fiber-reinforced resin composite material of the present invention are as follows:

[0030] Example 1

[0031] The preparation method of the fiber-reinforced resin composite material in this example specifically includes the following steps:

[0032] (1) Biaxial glass fiber woven fabrics with a single-layer thickness of 0.8 mm are stacked layer by layer, with a total of 30 layers stacked to obtain a stacked body. The stacked body is placed on the platform of an industrial sewing machine, and glass fibers with a diameter of 0.5 mm are used as sewing threads to penetrate and sew through the upper and lower layers in the thickness direction of the stacked body, so that the biaxial glass fiber woven fabrics in each layer in the stacked body are sewn together. When sewing, multiple groups of sewing threads are arranged at intervals in the width direction of the stacked body to form multiple sewing paths. Each sewing thread is sewn in the length direction of the stacked body. The interval between the sewing paths is 30 mm, and the sewing interval of each sewing thread is 10 mm. After sewing, a sewn body is obtained; the thickness ratio of the stacked body to the sewn body is 1:0.9. The cross-sectional view of the sewn body is as shown in Figure 1 shown, and the top view is as shown in Figure 2 shown.

[0033] (2) The sewn bodies obtained in step (1) are stacked one above the other up and down to obtain a laminated sewn body. The laminated sewn body is cut according to the shape of the compression molding die, and then the cut laminated sewn body is placed into the compression molding die. The schematic diagram of the compression molding die is as shown in Figure 3 shown.

[0034] (3) E51 resin, E44 resin, curing agent and curing accelerator are stirred and mixed and then heated to 120 °C to be fully melted to obtain a composite resin sizing. The composite resin sizing is placed in a mixing tank, and the temperature of the mixing tank is controlled at 60 °C. Then, the first-stage stirring is carried out. The stirring speed of the first-stage stirring is 10 r / min, and the stirring time is 30 min. Then, the second-stage stirring is carried out. The stirring speed of the second-stage stirring is 30 r / min, and the stirring time is 1 h; after stirring, the materials in the mixing tank are evacuated and degassed (the vacuum degree in the mixing tank is less than 100 Pa) to obtain a sizing for injection. In this step, the mass ratio of E51 resin, E44 resin, curing agent and curing accelerator is 50:100:1:0.2. The curing agent is methyltetrahydrophthalic anhydride, and the curing accelerator is 503.

[0035] (4) Connect the compression molding die to the injection system, evacuate the compression molding die for 1 h until the vacuum degree is stable; inject glue into the cavity of the die from the glue inlet of the compression molding die through the injection valve at an injection speed of 200 g / min. When the glue appears at the glue outlet at the other end of the die, stop injecting glue, close the overflow valve, and continue to maintain the injection pressure at 0.4 MPa to maintain the pressure holding state for curing and forming. Then place the compression molding die containing the injection material and the laminated stitched body in an oven for heating and curing (the heating and curing adopts a multi-stage curing process, specifically including one-stage curing, two-stage curing, three-stage curing, and four-stage curing in sequence; the one-stage curing temperature is 70 °C and the time is 1 h, the two-stage curing temperature is 80 °C and the time is 2 h, the three-stage curing temperature is 110 °C and the time is 5 h, the four-stage curing temperature is 130 °C and the time is 3 h, and the heating rate between each stage is 1 °C / min). After the heating and curing are completed, turn off the oven, cool the compression molding die with the oven to 70 °C, then take out the compression molding die from the oven, and then demold and take out the cured product in the compression molding die, and cool it to room temperature to obtain a fiber-reinforced resin composite material (the mass fraction of the laminated stitched body in the fiber-reinforced resin composite material is 70%). Trim and polish the fiber-reinforced resin composite material to obtain the finished material.

[0036] Example 2

[0037] The preparation method of the fiber-reinforced resin composite material in this example specifically includes the following steps:

[0038] (1) Stack double-axis fiberglass woven fabrics with a single-layer thickness of 0.8 mm layer by layer, a total of 20 layers, to obtain a stacked body. Place the stacked body on the platform of an industrial sewing machine, and use fiberglass with a diameter of 0.5 mm as the sewing thread to penetrate and sew through the upper and lower layers along the thickness direction of the stacked body, so that the double-axis fiberglass woven fabrics in each layer in the stacked body are sewn together. When sewing, multiple groups of sewing threads are arranged at intervals along the width direction of the stacked body to form multiple sewing paths. Each sewing thread is sewn along the length direction of the stacked body, the interval between the sewing paths is 30 mm, and the sewing interval of each sewing thread is 10 mm. After sewing, a stitched body is obtained; the thickness ratio of the stacked body to the stitched body is 1:0.95.

[0039] (2) Stack the stitched bodies obtained in step (1) up and down in sequence to obtain a laminated stitched body. Cut the laminated stitched body according to the shape of the compression molding die, and then put the cut laminated stitched body into the compression molding die.

[0040] (3) Stir and mix E51 resin, E44 resin, curing agent and curing accelerator, then heat to 120 °C for full melting to obtain a composite resin adhesive. Place the composite resin adhesive in a mixing tank, control the temperature of the mixing tank at 60 °C, and then carry out the first-stage stirring. The stirring speed of the first-stage stirring is 10 r / min, and the stirring time is 0.5 h. Then carry out the second-stage stirring. The stirring speed of the second-stage stirring is 30 r / min, and the stirring time is 1 h. After stirring, evacuate and degas the material in the mixing tank (the vacuum degree in the mixing tank is less than 100 Pa) to obtain a casting resin. In this step, the mass ratio of E51 resin, E44 resin, curing agent and curing accelerator is 50:100:1:0.2. The curing agent is methyltetrahydrophthalic anhydride, and the curing accelerator is 503.

[0041] (4) Connect the compression molding die to the injection system, evacuate the compression molding die for 1 h until the vacuum degree is stable; inject the resin into the cavity of the die through the resin injection valve at the resin inlet of the compression molding die. The injection speed is 200 g / min. When the resin appears at the resin outlet at the other end of the die, stop injecting, close the overflow valve, and continue to maintain the injection pressure at 0.4 MPa to maintain the pressure holding state for curing and molding. Then place the compression molding die filled with the casting resin and the laminated stitched body in an oven for heating and curing (the heating and curing adopts a multi-stage curing process, specifically including first-stage curing, second-stage curing, third-stage curing and fourth-stage curing in sequence; the first-stage curing temperature is 70 °C, and the time is 1 h, the second-stage curing temperature is 80 °C, and the time is 2 h, the third-stage curing temperature is 110 °C, and the time is 5 h, the fourth-stage curing temperature is 130 °C, and the time is 3 h. The heating rate between each stage is 1 °C / min). After the heating and curing is completed, close the oven, cool the compression molding die with the oven to 70 °C, then take out the compression molding die from the oven, and then demold and take out the cured product in the compression molding die, and cool it to room temperature to obtain a fiber-reinforced resin composite material (the mass fraction of the laminated stitched body in the fiber-reinforced resin composite material is 70%). Trim and polish the fiber-reinforced resin composite material to obtain a finished material.

[0042] The preparation method of the fiber-reinforced resin composite material of Examples 3-14 specifically includes the following steps:

[0043] (1) Stack double-axis fiberglass woven fabrics with a single-layer thickness of 0.8 mm layer by layer, a total of n layers, to obtain a stacked body. Place the stacked body on the platform of an industrial sewing machine, and use fiberglass with a diameter of 0.5 mm as the sewing thread to penetrate and sew through the upper and lower layers along the thickness direction of the stacked body, so that the double-axis fiberglass woven fabrics in each layer in the stacked body are sewn together. When sewing, multiple groups of sewing threads are arranged at intervals along the width direction of the stacked body to form multiple sewing paths. Each sewing thread is sewn along the length direction of the stacked body, and the interval between the sewing paths is L 1mm, the sewing interval of each suture is L 2 mm. After sewing is completed, a sewn body is obtained; the thickness ratio of the stacked body to the sewn body is x:y.

[0044] (2) Stack the sewn bodies obtained in m steps (1) one above the other to obtain a laminated sewn body. Cut the laminated sewn body according to the shape of the compression molding die, and then place the cut laminated sewn body into the compression molding die.

[0045] (3) Stir and mix E51 resin, E44 resin, curing agent and curing accelerator, and heat to 120 °C to fully melt to obtain a composite resin sizing. Place the composite resin sizing in a mixing tank, control the temperature of the mixing tank at 60 °C, and then carry out the first-stage stirring. The stirring speed of the first-stage stirring is 10 r / min, and the stirring time is 0.5 h. Then carry out the second-stage stirring. The stirring speed of the second-stage stirring is 30 r / min, and the stirring time is 1 h. After stirring is completed, evacuate and degas the material in the mixing tank (the vacuum degree in the mixing tank is less than 100 Pa) to obtain the injection sizing. In this step, the mass ratio of E51 resin, E44 resin, curing agent and curing accelerator is 50:100:1:0.2. The curing agent is methyltetrahydrophthalic anhydride, and the curing accelerator is 503.

[0046] (4) Connect the compression molding die to the injection system, evacuate the compression molding die for 1 h until the vacuum degree is stable; inject the sizing into the mold cavity of the mold from the glue inlet of the compression molding die through the injection valve. The injection speed is 200 g / min. When the sizing appears at the glue outlet at the other end of the mold, stop injecting, close the overflow valve, and continue to maintain the injection pressure at 0.4 MPa. Then place the compression molding die containing the injection sizing and the laminated sewn body in an oven for heating and curing (the heating and curing adopts a multi-stage curing process, specifically including one-stage curing, two-stage curing, three-stage curing and four-stage curing carried out in sequence; the temperature of the one-stage curing is 80 °C, and the time is 3 h. The temperature of the two-stage curing is 100 °C, and the time is 1 h. The temperature of the three-stage curing is 120 °C, and the time is 10 h. The temperature of the four-stage curing is 120 °C, and the time is 5 h. The heating rate between each stage is 1 °C / min). After the heating and curing is completed, close the oven, cool the compression molding die with the oven to 70 °C, then take out the compression molding die from the oven, and then demold and take out the cured product in the compression molding die, and cool it to room temperature to obtain a fiber-reinforced resin composite material (the mass fraction of the laminated sewn body in the fiber-reinforced resin composite material is w%). Trim and polish the fiber-reinforced resin composite material to obtain a finished material.

[0047] In the preparation methods of the fiber-reinforced resin composite materials of Example 1-2 and Example 3-13, the number of layers n of the stacked body, the interval L between the sewing paths 1 and the sewing interval L of each suture2 The thickness ratio of the stacked body to the stitched body is x:y, and the mass fraction w% of the laminated stitched body in the fiber-reinforced resin composite material is shown in Table 1.

[0048] Table 1 Specific values of relevant parameters in the preparation method of the fiber-reinforced resin composite materials of Examples 1-13

[0049] Preparation method n <![CDATA[L 1 > <![CDATA[L 2 > x:y m w Example 1 20 30 10 1:0.90 5 70 Example 2 30 30 10 1:0.90 5 70 Example 3 20 30 10 1:0.95 5 70 Example 4 20 30 5 1:0.90 5 70 Example 5 20 30 15 1:0.90 5 70 Example 6 20 20 10 1:0.90 5 70 Example 7 20 40 10 1:0.90 5 70 Example 8 20 30 10 1:0.80 5 70 Example 9 20 30 10 1:0.90 2 70 Example 10 20 30 10 1:0.90 8 70 Example 11 20 30 10 1:0.90 5 60 Example 12 20 30 10 1:0.90 5 80 Example 13 10 30 10 1:0.90 5 70

[0050] Comparative example

[0051] The preparation method of the fiber-reinforced resin composite material of this comparative example specifically includes the following steps:

[0052] (1) The biaxial glass fiber woven fabric with a single-layer thickness of 0.8 mm is stacked layer by layer, with a total of 150 layers stacked to obtain a stacked body. The stacked body is cut according to the shape of the compression molding die, and then the cut stacked body is placed into the compression molding die. The schematic diagram of the biaxial glass fiber woven fabric is as Figure 4 shown, and the side view of the stacked body is as Figure 5 shown.

[0053] (2) This step is the same as step (3) of Example 1.

[0054] (3) This step is the same as step (4) of Example 1.

[0055] II. The specific embodiments of the insulating pull rod of the present invention are as follows:

[0056] The insulating pull rod of this embodiment is prepared according to the preparation method of any one of the fiber-reinforced resin composite materials in Examples 1-14.

[0057] Experimental example

[0058] This experimental example is used to evaluate the mechanical properties of the fiber-reinforced resin composite materials prepared in each example and comparative example. Specifically, the compression strength of the fiber-reinforced resin composite materials prepared in each example and comparative example is tested according to the method in Standard GB / T 1041-2008, and the test conditions are as follows: the original gauge length is 10 mm, the specimen width is 10 mm, and the specimen thickness is 4 mm. At the same time, the flexural strength of the fiber-reinforced resin composite materials prepared in each example and comparative example is tested according to Standard GB / T 5130-1997. The experimental results are shown in Table 2.

[0059] Table 2 Mechanical properties of the fiber-reinforced resin composite materials prepared in each example and comparative example

[0060] Composite material Compressive strength (MPa) Flexural strength (MPa) Example 1 169.82 226.94 Example 2 168.79 223.43 Example 3 165.28 220.33 Example 4 158.71 211.61 Example 5 158.69 210.58 Example 6 167.47 223.29 Example 7 166.86 222.47 Example 8 161.76 215.68 Example 9 168.54 224.72 Example 10 167.89 223.85 Example 11 157.45 209.93 Example 12 151.35 201.80 Example 13 167.74 223.65 Comparative example 147.66 -

[0061] As can be seen from Table 2, from the test results of Example 1, Example 2 and Example 13, it can be seen that with different fiber layers, the compression ratio is the same, the interlayer spacing of the fiber layers is consistent, and the compression strength of the material is comparable. Comparing the test results of Example 1, Example 11 and Example 12, as the mass fraction of the fiber increases and the proportion of the epoxy resin component decreases, it is difficult for the epoxy resin and the fiber to be fully combined, and the internal defects of the material increase, resulting in a decrease in the mechanical strength of the material. From the test results of Example 1, Example 9 and Example 10, it can be seen that with different numbers of stacked bodies, the fiber mass fraction and the fiber compression ratio are consistent, and the material properties do not change significantly. Comparing Example 1 and Example 3, when the compression rate decreases, the fiber layer has a larger interlayer spacing, which promotes the flow and penetration of the resin. At the same time, the strengthening effect of the fiber weakens, resulting in a slight decrease in the compression strength of the material. According to the test results of Example 1, Example 4 and Example 5, when the suture line spacing is 10 mm, the highest compression strength is obtained. Combining Example 6 and Example 7, the suture line can improve the compression strength of the material and also slow down the flow of the resin. Too high a suture line density makes it difficult for the epoxy resin to be fully impregnated. Therefore, by regulating the density of the suture line and the interlayer spacing of the fiber layer, adjusting the reaction time and temperature of resin impregnation, and through the strengthening effect of the suture line, the compression strength of the material can be effectively improved.

Claims

1. A method for preparing a fiber-reinforced resin composite material, characterized in that: The method comprises the following steps: stacking several layers of glass fiber woven cloth to obtain a stacked body; then using glass fiber as a stitching line to perform through-and-through stitching of the upper and lower layers along the thickness direction of the stacked body to obtain a stitched body; then stacking several stitched bodies to obtain a laminated stitched body; and finally impregnating the laminated stitched body with resin and then curing it to obtain a fiber-reinforced resin composite material.

2. The method for preparing a fiber-reinforced resin composite material according to claim 1, characterized in that: The thickness ratio of the stacked body to the sutured body is 1:(0.9-0.95).

3. The method for preparing a fiber-reinforced resin composite material according to claim 1, characterized in that: The mass fraction of the laminated suture body in the fiber reinforced resin composite material is 65-70%.

4. The method for preparing a fiber-reinforced resin composite material according to claim 1, characterized in that: During suturing, a plurality of suture lines are arranged at intervals along the width direction of the stacked body to form a plurality of suture paths, and each suture line is sutured along the length direction of the stacked body.

5. The method for preparing a fiber-reinforced resin composite material according to claim 4, characterized in that: The interval between the suture paths is 20 to 40 mm, and the sewing interval between each suture line is 5 to 10 mm.

6. The method for preparing a fiber-reinforced resin composite material according to claim 1, characterized in that: The number of layers of the glass fiber woven cloth in the stacked body is 10 to 30.

7. The method for preparing a fiber-reinforced resin composite material according to claim 1, characterized in that: The number of stacked sutures in the laminated suture is 2 to 8.

8. The method for preparing a fiber-reinforced resin composite material according to any one of claims 1 to 7, characterized in that: The glass fiber woven cloth is a biaxial glass fiber woven cloth, and the thickness of a single layer is 0.6-1 mm; the diameter of the suture thread is 0.3-0.8 mm.

9. The method for preparing a fiber-reinforced resin composite material according to any one of claims 1 to 7, characterized in that: The resin is composed of epoxy resin, curing agent and curing accelerator; the curing includes one-stage curing, two-stage curing, three-stage curing and four-stage curing performed in sequence; The first stage curing temperature is 70-80℃, the time is 1-3h, the second stage curing temperature is 80-100℃, the time is 1-3h, the third stage curing temperature is 110-120℃, the time is 5-10h, and the fourth stage curing temperature is 120-130℃, the time is 3-5h.

10. An insulating pull rod prepared by the method for preparing a fiber-reinforced resin composite material according to any one of claims 1 to 9.

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