Carbon fiber nylon composite material and preparation method thereof

Abstract

The invention discloses a carbon fiber nylon composite material and a preparation method thereof, and belongs to the field of carbon fiber nylon composites.The method comprises the following steps that S1, carbon fiber tows and nylon fiber tows are prepared into carbon fiber nylon mixed yarn through a doubling technology; s2, laying and fixing the mixed yarns on a substrate according to a preset path by adopting a customized fiber laying technology to form a mixed fabric; s3, soaking the mixed fabric in a constant-temperature water bath, and drying; s4, the dried mixed fabric is placed in hot pressing equipment for hot pressing forming, and the carbon fiber nylon composite material is obtained after cooling.

Description

Technical Field

[0001] This invention relates to the field of high-performance fiber-reinforced thermoplastic composite materials, specifically to a carbon fiber nylon composite material and its preparation method. Background Technology

[0002] Carbon fiber composites are widely used in lightweight structural applications due to their superior properties such as high specific strength, high specific modulus, and corrosion resistance. Traditional carbon fiber composites often use thermosetting resins such as epoxy resins as the matrix, which suffers from problems such as long preparation cycles, high brittleness, and difficulty in recycling. Nylon, as a thermoplastic engineering plastic, possesses good toughness, wear resistance, and recyclability, making it an ideal matrix replacement. However, effectively combining carbon fiber with nylon faces two major challenges: first, the chemical inertness of carbon fiber surfaces results in poor wettability with polar nylon resins, leading to insufficient interfacial bond strength; second, traditional melt processing techniques struggle to achieve uniform distribution and controllable orientation of carbon fibers and are prone to fiber breakage, failing to fully realize their reinforcing potential.

[0003] To address the aforementioned issues, Chinese patent CN108690347B discloses a technical solution that balances the rigidity and toughness of a material by precisely controlling the distribution of carbon fiber length. This solution employs melt impregnation and injection molding processes, aiming to achieve a specific ratio of carbon fibers of different lengths in the composite material to achieve a "rigidity-toughness balance." However, this method essentially still falls under the category of random reinforcement of short fibers. The distribution of fibers in the matrix is ​​uncontrollable, making it impossible to achieve directional reinforcement for specific stress directions. Furthermore, damage to fiber length caused by the injection molding process is unavoidable, limiting further improvements in material performance. Chinese patent CN120737380A focuses on solving the moisture absorption and expansion problem of nylon materials. Its core technology involves complex surface coating treatment of carbon fibers, constructing nanoscale silicon-containing protrusions on the fiber surface to block water molecule diffusion. While this solution improves the dimensional stability of the composite material to some extent, its process involves high temperatures, vacuum, and various reactive gases, resulting in a complex and costly process. Moreover, it overemphasizes the interfacial barrier effect and fails to address the fundamental mechanical design problem of controllable fiber arrangement in the macroscopic structure, thus contributing limited to improving the material's load-bearing efficiency.

[0004] Therefore, there is an urgent need to develop a carbon fiber-nylon composite material and its preparation method that combines high strength, high toughness, excellent dimensional stability, good interfacial bonding, and simple and environmentally friendly processing. To address the problems of uncontrollable fiber distribution, weak interfacial bonding, and the process complexity caused by existing technologies in achieving specific properties in traditional processes, this invention innovatively proposes an integrated strategy combining fiber premixing, customized fiber placement design, and hot pressing: First, a uniform physical mixing of carbon fiber and nylon fiber is achieved at the yarn scale through a premixing process, laying the foundation for forming an ideal interface; then, programmable customized fiber placement (TFP) technology is used to lay the mixed yarn on a vinylon substrate in a preset path (such as a grid or disc shape), achieving precise control over fiber orientation and distribution, and constructing an optimal load-bearing network; subsequently, water bath treatment and drying are performed; finally, a precisely controlled hot pressing process is used to melt the nylon and fully impregnate the carbon fiber, forming a strong interface while preserving the structural integrity and design configuration of the fibers. This strategy not only solves the interfacial bonding problem at the micro level, but also realizes the designability of composite material properties at the macro level. At the same time, the entire process avoids complex chemical treatments and high temperature and high pressure environments, making it simple, environmentally friendly, and easy to scale up for production. It has successfully prepared high-performance carbon fiber nylon composite materials with comprehensive performance far exceeding that of existing technologies. Summary of the Invention

[0005] The purpose of this invention is to provide a carbon fiber-nylon composite material and its preparation method, addressing the problems of poor interfacial bonding between carbon fiber and nylon matrix, uncontrollable fiber distribution, and complex processes in existing technologies. To achieve the above objective, this invention employs a doubling process to uniformly mix carbon fiber and nylon fiber at the yarn scale, and combines this with customized fiber placement technology to achieve controllable fiber path placement in the macroscopic structure. Subsequently, through water bath treatment, drying, and hot pressing, the nylon matrix is ​​fully melted and impregnated with carbon fiber, thereby obtaining a carbon fiber-nylon composite material with excellent interfacial bonding performance and outstanding mechanical properties. Compared with existing technologies, this invention has a simple process flow, is environmentally friendly, and has good prospects for industrial application.

[0006] This invention boasts superior interfacial bonding strength: Through a doubling method, it achieves tight interweaving of carbon fibers and nylon at the yarn scale, significantly increasing their contact area. During subsequent hot pressing, molten nylon can achieve close-range coating of the carbon fibers without long-distance flow, effectively solving the problem of insufficient wetting caused by high melt viscosity in traditional processes, thus achieving extremely strong interfacial adhesion. Significantly improved mechanical properties: Thanks to the excellent interfacial bonding and optimal fiber orientation achieved through TFP technology, the composite material prepared by this invention can fully utilize the high strength and high modulus characteristics of carbon fibers. High designability of structure and performance: The core advantage of TFP technology lies in its digital programming capabilities. This invention allows for free design of fiber placement paths, densities, and orientations based on the stress distribution during product service, achieving customized material performance. It is particularly suitable for manufacturing load-bearing structural components, avoiding material waste and performance redundancy. Green and environmentally friendly process: The entire preparation process requires no organic solvents; the water bath treatment uses only warm water as a medium, with no toxic or harmful substances emitted, making it environmentally friendly and meeting clean production requirements. Excellent process integration and economy: This method cleverly combines textile technology with composite material molding technology. The process is simple and easy to automate and scale up production, which has high industrial application value and market prospects. Attached Figure Description

[0007] Figure 1 This is a schematic diagram showing the parallel arrangement of carbon fiber and nylon fiber. Figure 2 A schematic diagram of custom fiber placement; Figure 3 A schematic diagram of the fiber laying path; Figure 4 This is a schematic diagram of a hot pressing molding equipment. Detailed Implementation

[0008] The present invention will now be described in detail with reference to the accompanying drawings.

[0009] Example 1 Raw material preparation: Toray T300 type 3K carbon fiber tow and PA6 nylon industrial filaments from Japan were selected, both with a single filament fineness of 200 tex. The materials were prepared at a mass ratio of 1:1.

[0010] Doubling: Using a high-speed doubling machine, carbon fiber bundles and nylon bundles are combined and an appropriate amount of twist (7 twists / meter) is applied to produce a tightly structured and uniform carbon fiber and nylon blended yarn.

[0011] TFP Laying: Using a CNC custom fiber laying embroidery machine, the above-mentioned mixed yarns are laid in a 15mm×15mm grid path and sewn onto 100g / m2 vinylon water-soluble fabric to form a mixed fabric.

[0012] Water bath treatment and drying: Immerse the fabric in a constant temperature water bath at 50℃±2℃, ensuring complete submersion, and remove it after soaking for 1 hour. Gently squeeze out excess water with an absorbent roller, then lay it flat in an 80℃ forced-air drying oven for 2 hours to obtain the treated fabric.

[0013] Hot pressing: Cut the dried fabric into 150mm×150mm sheets and place them into the mold of the flat vulcanizing machine. Set the hot pressing temperature to 240℃, preheat for 5 minutes, then apply a pressure of 1MPa and hold for 20 minutes. After that, cool with water to below 60℃ while maintaining the pressure, open the mold and remove the sheet to obtain the final carbon fiber nylon composite material (3) plate.

[0014] Comparative Example 1: The difference from Example 1 is that the same carbon fiber and nylon are used, and the raw materials and amounts are the same. Comparative Example 1 does not use yarn bundling, but instead uses two guide yarns, one of which is carbon fiber and the other of which is nylon. The two yarns are laid side by side and close to each other, and the subsequent processes are the same.

[0015] Comparative Example 2: The difference from Example 1 is that only carbon fiber is laid during the customized laying process, while nylon uses two layers of film (the total amount is the same as in Example 1). During hot pressing, the film is placed on top and bottom of the carbon fiber fabric for hot pressing.

[0016] Comparative Example 3: The materials used are the same as those in Comparative Example 2, except that the carbon fiber fabric is made using existing methods. Specifically, carbon fibers are laid on a PTFE release film, and an extremely thin hot-melt mesh is covered on the laid carbon fiber layer for low-temperature setting. Then, it is hot-pressed in the same manner as in Comparative Example 2.

[0017] Results: Performance tests were conducted on the boards from Example 1 and Comparative Examples 1-3, and the results are shown in Table 1. In Table 1, the stiffness and tensile strength of Example 1 show a significant increase compared to Comparative Examples 1 and 2, and Comparative Example 3. The plying process in Example 1, compared to Comparative Examples 1 and 2, results in smaller and fewer pores between the carbon fiber and nylon materials, leading to better wettability. Although Comparative Example 2 does not show a significant performance improvement compared to Comparative Example 3 (commonly used in existing solutions), the use of vinylon water-soluble fabric and water bath treatment in Comparative Example 2 is simpler than existing processes, allowing for the formation of mesh structures of different shapes. It also allows for free design of fiber placement paths, densities, and orientations, enabling customized material performance. This is particularly suitable for manufacturing load-bearing structural components, avoiding material waste and performance redundancy.

Claims

1. A carbon fiber nylon composite material, characterized in that, The carbon fiber nylon composite material is prepared by laying and hot pressing a mixed yarn formed by plying carbon fiber and nylon fiber, wherein the mass ratio of carbon fiber to nylon fiber is 3:7 to 7:

3.

2. The carbon fiber nylon composite material according to claim 1, characterized in that, The mass ratio of carbon fiber to nylon fiber is 5:

5.

3. The carbon fiber nylon composite material according to claim 1 or 2, characterized in that, The nylon fiber is one or more of PA6, PA66, or PA610.

4. The carbon fiber nylon composite material according to any one of claims 1 to 3, characterized in that, The carbon fiber is 3K carbon fiber.

5. The carbon fiber nylon composite material according to claim 4, characterized in that, The blended yarn is produced by plying and applying twist, wherein the twist is 5 to 10 twists / meter.

6. A method for preparing the carbon fiber nylon composite material according to any one of claims 1 to 5, characterized in that, The process includes the following steps: S1, preparing carbon fiber and nylon fiber bundles into a carbon fiber-nylon hybrid yarn through a doubling process; S2, using a customized fiber laying technique, laying the hybrid yarn along a preset path and fixing it onto a water-soluble substrate to form a hybrid fabric; S3, immersing the hybrid fabric in a constant temperature water bath and then drying it; S4, placing the dried hybrid fabric in a hot pressing device for hot pressing molding, and obtaining a carbon fiber-nylon composite material after cooling.

7. The method for preparing carbon fiber nylon composite material according to claim 6, characterized in that, The preset path can be any one of a straight line, a grid, a spiral, or a contour path.

8. The method for preparing carbon fiber nylon composite material according to claim 6 or 7, characterized in that, The temperature of the constant temperature water bath is 48–52°C, and the soaking time is 0.5–2 hours.

9. The method for preparing carbon fiber nylon composite material according to claim 8, characterized in that, The drying process is carried out at a temperature of 70–90°C for 1–3 hours.

10. The method for preparing carbon fiber nylon composite material according to any one of claims 6 to 9, characterized in that, The hot pressing temperature is 220–300℃, the pressure is 0.5–1 MPa, and the holding time is 5–30 minutes.

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