Preparation method of thermoplastic composite wide-grid fabric prepreg

Abstract

This invention provides a method for preparing a wide-grid thermoplastic composite prepreg, relating to the field of thermoplastic composite technology. The prepreg is composed of reinforcing fibers and a thermoplastic resin matrix. The prepreg has a width of 1000 mm and a resin content deviation of ≤±3%. The reinforcing fibers are HSHF40A-12K carbon fibers with a tensile strength ≥5490 MPa, and the fiber surface contains 1% high-temperature sizing agent. The fiber areal density in the prepreg is 145 g / m². The thermoplastic resin matrix is ​​HBPEKK-HBK55 resin with a melting point of 310℃ and a particle size D50=25 μm. This invention overcomes the challenge of impregnating high-viscosity resin: through a "UD prepreg manufacturing-slitting-weaving" route, combined with high-temperature sizing agent fiber spreading technology and optimized impregnation molds, uniform impregnation of the carbon fibers with PEKK high-viscosity resin is achieved. The resin content deviation of the prepreg is controlled within ±3%, solving the problems of uneven impregnation and environmental pollution associated with traditional processes.

Description

Technical Field

[0001] This invention relates to the field of thermoplastic composite materials technology, and more particularly to a method for preparing thermoplastic composite wide-grid fabric prepreg. Background Technology

[0002] The urgent global manufacturing demand for lightweight, high-performance, and sustainable materials has driven the rapid development of thermoplastic composites. High-performance thermoplastic resins such as polyetheretherketone (PEKK) have become preferred matrices for large structural components due to their excellent high-temperature resistance, mechanical properties, and chemical stability. However, the preparation of existing thermoplastic composite prepregs still faces three major technological bottlenecks: Challenges of impregnating high-viscosity resins: PEKK resin has a high melt viscosity, making it difficult to achieve uniform wetting of fiber bundles using traditional melt impregnation processes; while solution impregnation processes have problems such as environmental pollution and residual solvents affecting performance, resulting in large deviations in the resin content of prepregs, making it difficult to meet high-precision requirements.

[0003] Wide-width production limitations: Traditional prepreg fabrics are typically less than 800mm wide, which cannot meet the integrated molding requirements of large aerospace structural components (such as wings and fuselage parts). Splicing processes will reduce structural strength and increase production complexity.

[0004] Performance fluctuations in wide-width components: During the production of wide-width prepregs, problems such as uneven fiber distribution and differences in resin impregnation can easily lead to fluctuations in mechanical properties, resulting in a high defect rate and a large coefficient of variation in key mechanical indicators, making it difficult to guarantee the reliability of large load-bearing structures.

[0005] Therefore, there is an urgent need to develop a technology that can overcome the above-mentioned technical bottlenecks and achieve the preparation of wide-width, high-precision, high-performance, and environmentally friendly thermoplastic composite prepregs. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for preparing thermoplastic composite wide-grid fabric prepreg.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a thermoplastic composite wide-grid fabric prepreg, composed of reinforcing fibers and a thermoplastic resin matrix, wherein the prepreg width is 1000 mm and the resin content deviation is ≤±3%; the reinforcing fiber is HSHF40A-12K carbon fiber with a tensile strength ≥5490MPa, the fiber surface contains 1% high-temperature sizing agent, and the fiber areal density in the prepreg is 145 g / ㎡; the thermoplastic resin matrix is ​​HBPEKK-HBK55 resin with a melting point of 310℃ and a particle size D50=25μm.

[0008] Preferably, the prepreg has a dry tensile strength ≥960MPa, a wet tensile strength ≥893MPa, a short beam shear strength ≥91MPa, and a post-impact compressive strength ≥330MPa.

[0009] Preferably, the interlaminar shear strength dispersion coefficient of the prepreg short beam is ≤3.04%.

[0010] The preparation method of thermoplastic composite large-grid prepreg adopts the "UD prepreg manufacturing-slitting-weaving" route, including the following steps: S1: Fiber spreading: Controlling the unwinding tension of HSHF40A-12K carbon fiber, through the coordinated action of guide rollers, tension rollers and spreading rollers, adjusting the heating temperature, pressing position and vibration frequency of the spreading roller, to prepare a fiber substrate with an areal density of 145g / ㎡. S2: Resin impregnation: HBPEKK-HBK55 resin is made into a suspension, and the fiber substrate is initially impregnated with resin through an impregnation tank equipped with an optimized impregnation mold; S3: Drying and melting: The resin-impregnated fiber substrate is sent into a drying and melting furnace. The furnace temperature is set to the PEKK melting point +50~100℃ to remove moisture and additives, so that the resin melts and adheres evenly to the fiber monofilaments. S4: Stretch and wind-up: Precisely control the traction rate and winding tension to stretch and wind up the prepreg before winding. S5: Slitting and weaving: The UD prepreg is slid into strips of a preset width and woven together at a preset angle to obtain a 1000mm wide fabric prepreg.

[0011] Preferably, in step S1, the unwinding tension of the carbon fiber is 5N, the heating temperature of the spreading roller is 80℃, the downward pressure is 2mm, and the vibration frequency is 5Hz.

[0012] Preferably, in step S2, the mass ratio of PEKK resin to deionized water is 1:3, and the speed at which the fiber substrate passes through the impregnation tank is 0.5 m / min.

[0013] Preferably, in step S3, the drying and melting furnace temperature is 360℃, the circulating fan speed is 2m / s, and the processing time is 5min.

[0014] Preferably, in step S4, the traction rate is 0.45 m / min and the winding tension is 8 N.

[0015] Preferably, in step S5, the UD prepreg is cut into strips with a width of 10 mm and an interlacing angle of 0° / 90°.

[0016] Compared with the prior art, the advantages and positive effects of the present invention are as follows: 1. Breakthrough in high-viscosity resin impregnation: By adopting the "UD prepreg manufacturing-slitting-weaving" route, combined with high-temperature sizing agent fiber spreading technology and optimized impregnation mold, uniform impregnation of carbon fiber with PEKK high-viscosity resin is achieved, and the resin content deviation of the prepreg is controlled within ±3%, solving the problems of uneven impregnation and environmental pollution caused by traditional processes. 2. Achieve stable wide-width production: Breaking the bottleneck of traditional prepreg widths of less than 800mm, stable production of 1000mm wide prepreg fabrics is achieved. This allows for seamless integration of large aerospace structural components without splicing, reducing production complexity and enhancing structural strength. Improved performance consistency and reliability: By precisely controlling key process parameters such as yarn unfolding temperature, traction rate, and drying temperature, and optimizing fiber arrangement and resin distribution, the prepreg achieves a short beam interlaminar shear strength dispersion coefficient of only 3.04%, a dry tensile strength of 960MPa, a wet tensile strength of 893MPa, and a short beam shear strength of 91MPa. These excellent mechanical properties with minimal fluctuations meet the reliability requirements of large load-bearing structural components. 3. Environmentally friendly and cost-controllable: It avoids the use of solvents in the solution impregnation process, so there is no environmental pollution problem; the process route is simple and efficient, wide-width production reduces splicing steps, reduces the manufacturing cost of large structural parts, and the recyclability of thermoplastic materials further improves resource utilization. 4. Strong application adaptability: Developed to meet the core requirements of "lightweight and long service life" for aerospace structural components, its mechanical properties are superior to traditional fabric prepregs. It can be widely used in large load-bearing structural components in aerospace, new energy vehicles and other fields, providing technical support for the lightweight and integrated development of high-end equipment. Attached Figure Description

[0017] Figure 1 The flowchart illustrates the preparation method of a thermoplastic composite wide-grid fabric prepreg proposed in this invention. Detailed Implementation

[0018] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0019] Thermoplastic composite wide-grid fabric prepreg is composed of reinforcing fibers and a thermoplastic resin matrix. The prepreg width is 1000 mm, and the resin content deviation is ≤±3%. The reinforcing fiber is HSHF40A-12K carbon fiber with a tensile strength ≥5490MPa. The fiber surface contains 1% high-temperature sizing agent, and the fiber areal density in the prepreg is 145 g / ㎡. The thermoplastic resin matrix is ​​HBPEKK-HBK55 resin with a melting point of 310℃ and a particle size D50=25μm.

[0020] The present invention provides a prepreg with a dry tensile strength ≥960MPa, a wet tensile strength ≥893MPa, a short beam shear strength ≥91MPa, and a post-impact compressive strength ≥330MPa.

[0021] According to this invention, the interlaminar shear strength dispersion coefficient of prepreg short beams is ≤3.04%.

[0022] A method for preparing a thermoplastic composite large-grid prepreg fabric adopts the "UD prepreg manufacturing-slitting-weaving" route, including the following steps: S1: Fiber spreading: Controlling the unwinding tension of HSHF40A-12K carbon fiber, through the coordinated action of guide rollers, tension rollers and spreading rollers, adjusting the heating temperature, pressing position and vibration frequency of the spreading roller, to prepare a fiber substrate with an areal density of 145g / ㎡. S2: Resin impregnation: HBPEKK-HBK55 resin is made into a suspension, and the fiber substrate is initially impregnated with resin through an impregnation tank equipped with an optimized impregnation mold; S3: Drying and melting: The resin-impregnated fiber substrate is sent into a drying and melting furnace. The furnace temperature is set to the PEKK melting point +50~100℃ to remove moisture and additives, so that the resin melts and adheres evenly to the fiber monofilaments. S4: Stretch and wind-up: Precisely control the traction rate and winding tension to stretch and wind up the prepreg before winding. S5: Slitting and weaving: The UD prepreg is slid into strips of a preset width and woven together at a preset angle to obtain a 1000mm wide fabric prepreg.

[0023] In step S1 of this invention, the unwinding tension of the carbon fiber is 5N, the heating temperature of the spreading roller is 80℃, the downward pressure is 2mm, and the vibration frequency is 5Hz.

[0024] In step S2 of this invention, the mass ratio of PEKK resin to deionized water is 1:3, and the speed at which the fiber substrate passes through the impregnation tank is 0.5 m / min.

[0025] In step S3 of this invention, the drying and melting furnace temperature is 360°C, the circulating fan speed is 2m / s, and the processing time is 5min.

[0026] In this invention, in step S4, the traction rate is 0.45 m / min and the winding tension is 8 N.

[0027] In step S5 of this invention, the UD prepreg is cut into strips with a width of 10 mm and an interlacing angle of 0° / 90°.

[0028] Example 1 Preparation of thermoplastic composite wide-grid fabric prepreg Raw material preparation: Reinforcing fiber: HSHF40A-12K carbon fiber, tensile strength 5490MPa, containing 1% high-temperature sizing agent; Resin matrix: HBPEKK-HBK55 resin, melting point 310℃, particle size D50=25μm; Auxiliary equipment: yarn spreading machine, dip tank (including optimized dip mold), drying and melting furnace, drafting and winding machine, slitting and weaving machine.

[0029] Preparation process: S1: Fiber spreading: Adjust the unwinding tension of the spreading machine to 5N, the spreading roller heating temperature to 80℃, the downward pressure to 2mm, and the vibration frequency to 5Hz, so as to spread the carbon fiber bundle flat and obtain a fiber substrate with an areal density of 145g / ㎡. S2: Resin impregnation: PEKK resin and deionized water are mixed at a mass ratio of 1:3 to form a suspension, which is then injected into the impregnation tank. The fiber substrate passes through the impregnation tank at a speed of 0.5 m / min. The width of the impregnation mold flow channel is adapted to the width of the fiber substrate. S3: Drying and Melting: The resin-impregnated fiber substrate is sent into a drying and melting furnace. The furnace temperature is set to 360℃ (PEKK melting point +50℃), the circulating fan speed is 2m / s, and the processing time is 5min. Moisture and additives are discharged, so that the resin melts and adheres evenly to the fiber monofilament. S4: Stretch and wind: Stretch rate 0.45m / min, wind tension 8N, wind and wind the prepreg after stretching and finishing; S5: Slitting and weaving: Using a tension-adjustable slitting knife, the UD prepreg is slit into strips with a width of 10mm. The strips are then woven at 0° / 90° interlacing angles under computer graphic control to obtain a 1000mm wide prepreg fabric.

[0030] Example 2: Performance Testing and Comparison The performance of the prepreg prepared in Example 1 was tested, and a conventional PEKK fabric prepreg with a width of 700 mm was selected as a control sample. The test standards are as follows: tensile strength: GB / T3354-2014; short beam shear strength: GB / T3355-2014; post-impact compressive strength: ASTM D7137; resin content: GB / T2577-2005; coefficient of variation: calculated based on the test results of 10 parallel samples. The test results are shown in the table below:

[0031] Test results show that the wide-grid prepreg fabric prepared by this invention, while increasing the width to 1000mm, has a resin content deviation controlled within ±3%, and all mechanical properties are superior to those of traditional prepregs. Moreover, the performance consistency is significantly improved, and the dispersion coefficient of interlaminar shear strength of short beams is only 44.6% of that of traditional prepregs, which fully meets the requirements for use in large aerospace structural components.

[0032] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A thermoplastic composite prepreg with a large mesh width, characterized in that: Composed of reinforcing fibers and a thermoplastic resin matrix, the prepreg has a width of 1000 mm and a resin content deviation of ≤±3%; the reinforcing fiber is HSHF40A-12K carbon fiber with a tensile strength ≥5490MPa, the fiber surface contains 1% high-temperature sizing agent, and the fiber areal density in the prepreg is 145g / ㎡; the thermoplastic resin matrix is ​​HBPEKK-HBK55 resin with a melting point of 310℃ and a particle size D50=25μm.

2. The thermoplastic composite wide-grid fabric prepreg according to claim 1, characterized in that: The prepreg has a dry tensile strength ≥960MPa, a wet tensile strength ≥893MPa, a short beam shear strength ≥91MPa, and a post-impact compressive strength ≥330MPa.

3. The thermoplastic composite wide-grid fabric prepreg according to claim 1, characterized in that: The interlaminar shear strength dispersion coefficient of the prepreg short beam is ≤3.04%.

4. A method for preparing a thermoplastic composite wide-grid fabric prepreg as described in any one of claims 1-3, characterized in that, The "UD prepreg manufacturing-slitting-weaving" route includes the following steps: S1: Fiber spreading: Controlling the unwinding tension of HSHF40A-12K carbon fiber, through the coordinated action of guide rollers, tension rollers and spreading rollers, adjusting the heating temperature, pressing position and vibration frequency of the spreading roller, to prepare a fiber substrate with an areal density of 145g / ㎡. S2: Resin impregnation: HBPEKK-HBK55 resin is made into a suspension, and the fiber substrate is initially impregnated with resin through an impregnation tank equipped with an optimized impregnation mold; S3: Drying and melting: The resin-impregnated fiber substrate is sent into a drying and melting furnace. The furnace temperature is set to the PEKK melting point +50~100℃ to remove moisture and additives, so that the resin melts and adheres evenly to the fiber monofilaments. S4: Stretch and wind-up: Precisely control the traction rate and winding tension to stretch and wind up the prepreg before winding. S5: Slitting and weaving: The UD prepreg is slid into strips of a preset width and woven together at a preset angle to obtain a 1000mm wide fabric prepreg.

5. The method for preparing the thermoplastic composite wide-grid fabric prepreg according to claim 4, characterized in that: In step S1, the unwinding tension of the carbon fiber is 5N, the heating temperature of the spreading roller is 80℃, the downward pressure is 2mm, and the vibration frequency is 5Hz.

6. The method for preparing the thermoplastic composite wide-grid fabric prepreg according to claim 4, characterized in that: In step S2, the mass ratio of PEKK resin to deionized water is 1:3, and the fiber substrate passes through the impregnation tank at a speed of 0.5 m / min.

7. The method for preparing the thermoplastic composite wide-grid fabric prepreg according to claim 4, characterized in that: In step S3, the drying and melting furnace temperature is 360℃, the circulating fan speed is 2m / s, and the processing time is 5min.

8. The method for preparing the thermoplastic composite wide-grid fabric prepreg according to claim 4, characterized in that: In step S4, the traction rate is 0.45 m / min and the winding tension is 8 N.

9. The method for preparing the thermoplastic composite wide-grid fabric prepreg according to claim 4, characterized in that: In step S5, the UD prepreg is cut into strips with a width of 10 mm and an interlacing angle of 0° / 90°.

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