Large-tow carbon fiber composite material device and preparation method

Abstract

According to the large-tow carbon fiber composite material device and the preparation method, large-tow carbon fibers to be spread are subjected to yarn spreading treatment through the multi-stage yarn splitting roller set, the multi-stage yarn splitting roller set is formed by alternately arranging the hot rollers and the non-hot rollers, and therefore the situation that due to the arrangement, the yarn spreading speed is low, the fibers are excessively softened can be avoided. The shortest flow guide path is adopted to infiltrate the large-tow carbon fibers subjected to yarn spreading treatment, and the shorter the flow guide path is, the smaller the porosity of the composite material is, so that the mechanical property of the finally prepared large-tow carbon fiber warp knitting fabric composite material is greatly improved, and the mechanical level of the small-tow carbon fiber prepreg is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field related to the preparation of large tow carbon fiber composites, and particularly relates to a device and a preparation method for large tow carbon fiber composites. Background Art

[0002] The statements in this part only provide background technical information related to the present invention and do not necessarily constitute prior art.

[0003] Large tow carbon fiber (≥48k) is increasingly widely used in the fields of wind power, rail transit, aerospace, etc. due to its low cost and excellent mechanical properties. However, due to the dense tow, uneven fiber distribution, hairiness breakage are likely to occur during warping, and the resin does not fully infiltrate the large tow fibers during the vacuum infusion process of its warp knitted fabric, which is likely to cause pore defects and lead to a decrease in the mechanical properties of the composite material. Summary of the Invention

[0004] To overcome the deficiencies of the above-mentioned prior art, the present invention provides a device and a preparation method for large tow carbon fiber composites. A multi-stage yarn spreading roller group with alternating hot rollers and non-hot rollers is used to spread the large tow carbon fiber, which can avoid excessive softening of the fiber caused by a slow yarn spreading speed.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a device for preparing large tow carbon fiber composites, including: A yarn spreading device, the yarn spreading device includes a multi-stage yarn spreading roller group, and the multi-stage yarn spreading roller group is composed of alternating hot rollers and non-hot rollers; The large tow carbon fiber to be spread is uniformly spread under the action of the multi-stage yarn spreading roller group in sequence.

[0006] In a second aspect, the present invention provides a method for preparing large tow carbon fiber composites, using the above-mentioned device for preparing large tow carbon fiber composites, and the method includes: Performing a yarn spreading treatment on the large tow carbon fiber; Infiltrating the large tow carbon fiber after the yarn spreading treatment with resin through the shortest diversion path to obtain large tow carbon fiber composites.

[0007] The above one or more technical solutions have the following beneficial effects: The present invention uses a multi-stage yarn spreading roller group to perform a yarn spreading treatment on the large tow carbon fiber to be spread. The multi-stage yarn spreading roller group is composed of alternating hot rollers and non-hot rollers. Such a setting can avoid excessive softening of the fiber caused by a slow yarn spreading speed.

[0008] The present invention infiltrates the large tow carbon fiber after spreading treatment by using the shortest diversion path. The shorter the diversion path, the smaller the porosity of the composite material, so that the mechanical properties of the finally prepared woven composite material of large tow carbon fiber are greatly improved, reaching the mechanical level of the prepreg of small tow carbon fiber.

[0009] Advantages of additional aspects of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0011] Figure 1 Schematic diagram of a two-layer multi-stage yarn splitting roller group in an embodiment of the present invention; Figure 2 Schematic diagram of resin inlet and outlet in different schemes in an embodiment of the present invention; Figure 3 Schematic diagram of the influence of the diversion path on the porosity of the composite material in an embodiment of the present invention; Figure 4 Flow chart of preparing a composite material sample in an embodiment of the present invention; Figure 5 Comparison diagram of the mechanical properties of the composite material in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0012] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0013] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention.

[0014] Without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0015] Embodiment 1 This embodiment discloses a device for preparing a large tow carbon fiber composite material, including: A spreading device, the spreading device includes a multi-stage yarn splitting roller group, and the multi-stage yarn splitting roller group is composed of alternately arranged hot rollers and non-hot rollers; The large tow carbon fiber to be spread is uniformly spread under the action of the multi-stage yarn splitting roller group in sequence.

[0016] In this embodiment, a multi-stage yarn spreading roller group is used to spread the large tow carbon fiber of the yarn to be spread. The multi-stage yarn spreading roller group is arranged with hot rollers and non-hot rollers alternatingly, and this setting can avoid excessive softening of the fibers caused by a slow yarn spreading speed.

[0017] In this embodiment, the yarn spreading device includes a first-layer multi-stage yarn spreading roller group and a second-layer multi-stage yarn spreading roller group; the first-layer multi-stage yarn spreading roller group and the second-layer multi-stage yarn spreading roller group simultaneously spread the large tow carbon fiber of the yarn to be spread evenly.

[0018] In this embodiment, two layers of multi-stage yarn spreading roller groups are used to spread the large tow carbon fiber of the yarn to be spread. The alternating arrangement of hot rollers and non-hot rollers can avoid excessive softening of the fibers caused by a slow yarn spreading speed. At the same time, spreading with two layers can ensure that the single-layer 150 g / m 2 carbon fiber is spread evenly, and a 300 g / m 2 biaxial warp knitted fabric is prepared, successfully realizing the preparation of a small gram weight warp knitted fabric from large tow carbon fiber.

[0019] Among them, the arrangement of the yarn spreading rollers in the first-layer multi-stage yarn spreading roller group and the second-layer multi-stage yarn spreading roller group is the same.

[0020] As an alternative embodiment, as Figure 1 shown, the first-layer multi-stage yarn spreading roller group and the second-layer multi-stage yarn spreading roller group respectively include a first roller, a second roller, a third roller, a fourth roller, a fifth roller and a sixth roller; among them, the first roller, the third roller and the fifth roller are hot rollers, and the second roller, the fourth roller and the sixth roller are non-hot rollers.

[0021] Among them, the temperature of the hot rollers is 150°C - 170°C, and the temperature of the non-hot rollers is 20°C - 25°C, which is room temperature.

[0022] As an alternative embodiment, the temperature of the first roller is 150 ± 2°C, the temperature of the second roller is 20°C - 25°C, the temperature of the third roller is 160 ± 2°C, the temperature of the fourth roller is 20°C - 25°C, the temperature of the fifth roller is 170 ± 2°C, and the temperature of the sixth roller is 20°C - 25°C.

[0023] The tow carbon fiber tow is dense, and the yarn spreading speed should not be too fast. In this embodiment, two layers of multi-stage yarn spreading roller groups are used. The multi-stage yarn spreading roller group is arranged with hot rollers and non-hot rollers alternatingly. By controlling the temperature gradient (150°C - 170°C) (150 ± 2°C, room temperature, 160 ± 2°C, room temperature, 170 ± 2°C, room temperature), the sizing agent on the surface of the fiber bundle is gradually softened. The alternating arrangement of hot rollers and non-hot rollers and the temperature gradient avoid excessive softening of the fibers caused by a slow yarn spreading speed. At the same time, spreading with two layers can ensure that the single-layer 150 g / m 2 carbon fiber is spread evenly, and a 300 g / m 2The ±45° biaxial warp knitted fabric has successfully achieved the preparation of a lightweight warp knitted fabric from large tow carbon fiber.

[0024] Example Two The purpose of this example is to provide a method for preparing a large tow carbon fiber composite material. A device for preparing a large tow carbon fiber composite material as in Example One is used, including: Carry out spreading treatment on the large tow carbon fiber; Infiltrate the spread large tow carbon fiber with resin through the shortest flow path to obtain a large tow carbon fiber composite material.

[0025] In this example, the influence of the flow path on the porosity of the composite material is explored through process simulation, and then it is determined to infiltrate the spread large tow carbon fiber with the shortest path. The shorter the flow path, the smaller the porosity of the final composite material, and the more complete the resin fills the fibers.

[0026] In this example, exploring the influence of the flow path on the porosity of the composite material through process simulation includes: Construct a three-dimensional solid model of the composite material and embed flow paths of different lengths in the three-dimensional solid model; Use simulation software for simulation to analyze the influence of different flow paths on the porosity of the composite material microscopically and macroscopically; Determine according to the analysis results that the shortest flow path has the least influence on the porosity of the composite material.

[0027] Specifically, construct a three-dimensional solid model according to the size and structure of the composite material, determine the material properties of the composite material, such as the elastic modulus, Poisson's ratio, density, etc. of the fiber and matrix. The property data can be obtained through experimental methods; embed flow paths of different lengths in the three-dimensional solid model, and then import it into the mesh generation software to generate a mesh for the three-dimensional solid model; set the resin injection conditions and set parameters such as injection pressure, speed or flow rate. At the same time, determine the injection time and the conditions for stopping injection, and set the boundary constraint conditions of the model according to the actual forming process; use simulation software such as PAM-RTM software for simulation. Before starting the simulation, initialize the model. During the simulation calculation process, solve the flow equation and mass conservation equation of the resin in the composite material according to the defined model, boundary conditions and material properties, etc., to obtain the flow velocity, pressure distribution and porosity change of the resin, and continuously update the position and state of the resin until the conditions for stopping the calculation are met, such as the resin completely fills the mold or reaches the set calculation time.

[0028] In this embodiment, three kinds of flow guiding paths are set, which are 800mm, 400mm, and 200mm respectively. Using simulation software, numerical simulation analysis of vacuum infusion molding is carried out on the CAD model of a specimen with dimensions of 800×400×2mm. The ply design is 6 layers (single layer 300g / m 2 , ±45° biaxial warp knitted fabric) full ply. The simulation type is Filling, the gravity factor (G = 9.81 m / s2) is added, the output frequency type is %Fill, the frequency is 2.5, the total ply thickness is 2mm. The three flow guiding paths and their effects on the microscopic and macroscopic porosities of the composite material are as Figure 2 , Figure 3 shown. It is found that microscopic pores are rapidly formed at the beginning of mold filling, and their defects are the largest near the resin injection end, showing a decreasing trend as the resin flow path extends. The macroscopic porosity in the resin injection end area always maintains a zero-porosity state. As the resin front advances towards the exhaust end, the pore density shows a gradient increasing trend. Considering the changing trends of macroscopic and microscopic porosities, that is, the shorter the flow guiding path, the smaller the porosity of the final composite material, and the more complete the resin filling of the fibers.

[0029] According to Figure 2 the vacuum infusion flow guiding path in the middle figure, a large tow carbon fiber composite material sample is prepared. When preparing the sample, the ply sequence is 300g / m 2 , ±45° biaxial fabric × 6. The specific operation is as Figure 4 shown. Apply a release agent on the surface of the glass mold, lay a layer of release cloth, then lay the carbon fiber cloth according to the ply, and lay another layer of release cloth on the surface of the carbon fiber cloth. The two layers of release cloth ensure that both sides of the sample are rough, which is convenient for subsequent mechanical property tests. After the overall vacuum bag is applied, evacuate to -0.1MPa and keep the pressure for 10 minutes. Preheat the resin and curing agent, fully mix the resin and curing agent in a ratio of 100:15, then carry out resin infusion and cure at 85°C for 2 hours. After natural cooling, demold.

[0030] Through the collaborative optimization of structure and process, the present invention adopts two-layer multi-stage yarn splitting roller groups combined with temperature gradient control to achieve a fiber dispersion uniformity > 90%. At the same time, through process simulation, the influence of the flow guiding path on the porosity of the composite material during the vacuum infusion process is explored, and a suitable flow guiding path is selected. Finally, the mechanical properties of the prepared large tow carbon fiber warp knitted fabric composite material are greatly improved, reaching the mechanical level of small tow carbon fiber prepreg.

[0031] Although the specific implementation manners of the present invention are described above in conjunction with the accompanying drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.

Claims

1. An apparatus for preparing a large tow carbon fiber composite material, characterized in that, Including: A yarn spreading device, the yarn spreading device includes a multi-stage yarn splitting roller group, and the multi-stage yarn splitting roller group is composed of alternately arranged hot rollers and non-hot rollers; The large tow carbon fiber to be spread is evenly spread under the action of the multi-stage yarn splitting roller group in turn.

2. The preparation device for large tow carbon fiber composite material according to claim 1, characterized in that, The multi-stage yarn splitting roller group includes a first roller, a second roller, a third roller, a fourth roller, a fifth roller and a sixth roller; wherein, the first roller, the third roller and the fifth roller are hot rollers, and the second roller, the fourth roller and the sixth roller are non-hot rollers.

3. The preparation device for large tow carbon fiber composite material according to claim 1 or 2, characterized in that The temperature adopted by the hot roller is 150°C - 170°C.

4. The preparation device for large tow carbon fiber composite material according to claim 1 or 2, characterized in that, The temperature adopted by the non-hot roller is 20°C - 25°C.

5. The preparation device for a large tow carbon fiber composite material according to claim 2, characterized in that, The temperature adopted by the first roller is 150 ± 2°C, the temperature adopted by the second roller is 20°C - 25°C, the temperature adopted by the third roller is 160 ± 2°C, the temperature adopted by the fourth roller is 20°C - 25°C, the temperature adopted by the fifth roller is 170 ± 2°C, and the temperature adopted by the sixth roller is 20°C - 25°C.

6. The preparation device for large tow carbon fiber composite material according to claim 1, characterized in that, The yarn spreading device includes a first-layer multi-stage yarn splitting roller group and a second-layer multi-stage yarn splitting roller group; the first-layer multi-stage yarn splitting roller group and the second-layer multi-stage yarn splitting roller group simultaneously spread the large tow carbon fiber to be spread evenly.

7. A method for preparing a large tow carbon fiber composite material, which uses a device for preparing a large tow carbon fiber composite material according to any one of claims 1-4, characterized in that, The method includes: Performing a yarn spreading treatment on the large tow carbon fiber; Infiltrating the resin through the shortest flow path into the large tow carbon fiber after the yarn spreading treatment to obtain a large tow carbon fiber composite material.

8. The method for preparing a large tow carbon fiber composite material according to claim 7, characterized in that, The determination of the shortest flow path is specifically as follows: Constructing a three-dimensional solid model of the composite material and embedding different lengths of flow paths in the three-dimensional solid model; Performing simulation using simulation software to analyze the influence of different flow paths on the porosity of the composite material microscopically and macroscopically; Determining that the shortest flow path has the least influence on the porosity of the composite material according to the analysis results.

9. The preparation method of a large tow carbon fiber composite material according to claim 8, characterized in that, Before performing the simulation using the simulation software, it also includes setting resin injection conditions and determining the injection time and stop time.

10. A method for preparing a large tow carbon fiber composite material according to claim 7, characterized in that, The shorter the flow path, the smaller the influence on the porosity of the composite material, and the more complete the resin fills the fibers.

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