Preparation method of thermoplastic resin-based carbon fiber prepreg tape

Abstract

The invention relates to a preparation method of a thermoplastic resin-based carbon fiber prepreg tape. The method comprises the following steps: performing electrochemical oxidation treatment on a carbon fiber tow, and introducing a polar functional group on the surface of the carbon fiber tow; drying and spreading the obtained carbon fiber tows, impregnating the carbon fiber tows in a thermoplastic resin dispersion liquid, and then drying and molding to obtain a thermoplastic resin-based carbon fiber prepreg tape; wherein the thermoplastic resin dispersion liquid is a thermoplastic resin solution containing aluminosilicate, nanocellulose and sodium carboxymethyl cellulose, and the dispersion liquid does not contain a surfactant and a defoaming agent; the dosage of the aluminosilicate is 2.7 w / w%-3.6 w / w% of the mass of the thermoplastic resin, the dosage of the nanocellulose is 0.7 w / w%-1.2 w / w% of the mass of the dispersion liquid, and the dosage of the sodium carboxymethyl cellulose is 1.1 w / w%-1.5 w / w% of the mass of the dispersion liquid.

Description

Technical Field

[0001] This invention relates to the field of thermoplastic resin-based carbon fiber composite materials, and in particular to a method for preparing thermoplastic resin-based carbon fiber prepreg tape. Background Technology

[0002] With the trend towards lightweighting in modern high-performance materials, developing lightweight and high-strength high-performance materials is of significant practical importance. Carbon fiber reinforced thermoplastic composites (CFRTPs) are widely used in aerospace, automotive lightweighting, and other fields due to their excellent mechanical properties, chemical corrosion resistance, and reprocessability. Thermoplastic resins, such as polyetheretherketone (PEEK), have become one of the most commonly used resin matrices for thermoplastic carbon fiber composites due to their good fatigue resistance and mechanical properties. Carbon fiber / PEEK prepreg tapes are precursors for preparing high-performance thermoplastic carbon fiber composites, and the properties of the precursor materials largely determine the properties of the composite materials prepared from them. Currently, existing technologies for preparing carbon fiber / PEEK prepreg tapes generally suffer from problems such as poor resin dispersion, high porosity, complex processes, and poor environmental performance.

[0003] CN 119748926 A discloses a method for manufacturing a carbon fiber / PEEK fabric thermoplastic prepreg, comprising: impregnating carbon fibers in a thermoplastic resin suspension; weaving the impregnated carbon fibers into a fabric; finally impregnating the carbon fiber fabric again, drying, and hot-pressing to obtain the carbon fiber / PEEK prepreg. The porosity of the finally obtained carbon fiber / PEEK prepreg is as high as 4% or more. This method, through two impregnations of carbon fibers, still produces a large porosity in the final carbon fiber / PEEK prepreg.

[0004] CN 118685009 A discloses a high-toughness carbon fiber prepreg tape and its preparation method, comprising mixing carbon fiber, carbon nanotubes, aluminosilicate fibers, and conductive fibers into powder; dispersing the fiber powder in xylene; adding resin to the fiber / xylene suspension; progressively adding nanofillers, zirconium dioxide, antistatic agents, UV stabilizers, flame retardants, surfactants, antioxidants, and anti-carbonization agents; and finally, mixing, filtering, solvent removal, molding, hot pressing, cutting, and packaging to obtain the carbon fiber prepreg tape. The carbon fiber prepreg tape prepared by this method requires the addition of a large amount of chemical additives, raising environmental concerns. The variety of fillers significantly affects the mechanical properties of the carbon fiber prepreg tape.

[0005] CN 113652073 A discloses a continuous carbon fiber reinforced polyarylether nitrile composite prepreg tape and its preparation method, comprising: dissolving polyarylether nitrile resin in alcohol or ketone solvents to form a resin solution; and preparing a unidirectional carbon fiber composite prepreg tape through a solution prepreg process. The carbon fiber prepreg tape prepared by this method has acceptable strength, but requires the recovery of a large amount of organic solvent, resulting in poor overall environmental performance and high production costs. Summary of the Invention

[0006] This invention covers the following technical solutions:

[0007] This invention relates to a method for preparing thermoplastic resin-based carbon fiber prepreg tape, which includes the following steps:

[0008] Electrochemical oxidation treatment is performed on carbon fiber bundles to introduce polar functional groups on their surface.

[0009] The obtained carbon fiber bundles were dried and spread out, then impregnated in a thermoplastic resin dispersion, and subsequently dried and shaped to obtain a thermoplastic resin-based carbon fiber prepreg tape.

[0010] The thermoplastic resin dispersion is a thermoplastic resin solution containing aluminosilicate, nanocellulose, and sodium carboxymethyl cellulose, and the dispersion does not contain surfactants or defoamers; the amount of aluminosilicate is 2.7 w / w % to 3.6 w / w % of the mass of the thermoplastic resin, the amount of nanocellulose is 0.7 w / w % to 1.2 w / w % of the mass of the dispersion, and the amount of sodium carboxymethyl cellulose is 1.1 w / w % to 1.5 w / w % of the mass of the dispersion.

[0011] This invention achieves single-pass continuous preparation under surfactant / defoamer-free conditions by electrochemically oxidizing the carbon fiber surface and combining it with a ternary stable dispersion system of aluminosilicate-nanocellulose-CMC. This significantly reduces porosity, improves interfacial bonding and mechanical properties, and has the advantages of being environmentally friendly, economical and suitable for large-scale production. Attached Figure Description

[0012] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the electrochemical oxidation process for the carbon fiber tow surface used in this invention.

[0014] Figure 2The a and ad diagrams are metallographic images of the cross-sections of the thermoplastic resin-based carbon fiber prepreg tapes obtained from routes 1-4, respectively; the corresponding porosities are: a = 1.43%, b = 2.90%, c = 4.35%, and d = 6.51%. Detailed Implementation

[0015] Reference will now be made to detailed embodiments of the present invention, one or more of which are described below. Each example is provided for explanation and not for limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from its scope or spirit. For example, features described or illustrated as part of one embodiment may be used in another embodiment to produce further embodiments.

[0016] Unless otherwise stated, all terms used to disclose this invention (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Further guidance is provided below for a better understanding of the teachings of this invention. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0017] In this invention, unless otherwise stated, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. Furthermore, to better understand this invention, definitions and explanations of relevant terms are provided below.

[0018] The terms “containing,” “comprising,” and “including” as used in this invention are synonyms and are inclusive or open-ended, not excluding additional, uncited members, elements, or method steps.

[0019] In this invention, the numerical range represented by endpoints includes all numerical values ​​and fractions contained within that range, as well as the endpoints mentioned.

[0020] Furthermore, in describing representative embodiments of the invention, this specification may present the methods and / or processes of the invention as a specific sequence of steps. However, the method or process should not be limited to the specific order of the steps described herein, to the extent that the method or process does not depend on the specific order of the steps presented herein. As will be understood by those skilled in the art, other sequences of steps are also possible. Therefore, the specific order of steps presented in the specification should not be construed as a limitation of the claims. Additionally, the claims relating to the methods and / or processes of the invention should not be limited to the execution of their steps in the order they are written, and those skilled in the art will readily recognize that the sequence can be changed while still remaining within the spirit and scope of the invention.

[0021] This invention relates to concentration values, which include fluctuations within a certain range. For example, fluctuations are allowed within a corresponding precision range. For instance, 2% can fluctuate within ±0.1%. For larger values ​​or values ​​that do not require overly precise control, even greater fluctuations are permitted.

[0022] As used in this invention, unless otherwise stated, the singular forms of the articles “a,” “an,” and “the” include plural referents.

[0023] In this invention, the terms "multiple" or "various" are used unless otherwise specified, referring to a quantity of 2 or more.

[0024] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0025] In this invention, terms such as "preferred," "better," "more suitable," and "ideal" merely describe implementation methods or embodiments with better effects and should be understood not to limit the scope of protection of this invention. In this invention, terms such as "optionally," "optionally," and "optional" mean that something is optional, that is, selected from either "with" or "without" a parallel solution. If multiple "optional" statements appear in a technical solution, unless otherwise specified and without contradiction or mutual constraint, each "optional" statement is independent.

[0026] This invention relates to a method for preparing thermoplastic resin-based carbon fiber prepreg tape, which includes the following steps:

[0027] Electrochemical oxidation treatment is performed on carbon fiber bundles to introduce polar functional groups on their surface.

[0028] The obtained carbon fiber bundles were dried and spread out, then impregnated in a thermoplastic resin dispersion, and subsequently dried and shaped to obtain a thermoplastic resin-based carbon fiber prepreg tape.

[0029] The thermoplastic resin dispersion is a thermoplastic resin solution containing aluminosilicate, nanocellulose, and sodium carboxymethyl cellulose, and the dispersion does not contain surfactants or defoamers; the amount of aluminosilicate is 2.7 w / w % to 3.6 w / w % of the mass of the thermoplastic resin, the amount of nanocellulose is 0.7 w / w % to 1.2 w / w % of the mass of the dispersion, and the amount of sodium carboxymethyl cellulose is 1.1 w / w % to 1.5 w / w % of the mass of the dispersion.

[0030] This invention has at least one of the following technical effects:

[0031] 1. Reduce porosity and improve density

[0032] The introduction of a ternary system of functional aluminosilicates, nanocellulose, and sodium carboxymethyl cellulose into the dispersion enables stable dispersion of thermoplastic resin powder without the use of surfactants and defoamers, inhibiting bubble formation and agglomeration. Therefore, the resin distribution in the prepreg tape is uniform, the porosity is significantly lower than in existing processes, and the product exhibits better density.

[0033] 2. Enhance interface integration

[0034] Electrochemical oxidation introduces polar functional groups onto the carbon fiber surface, which then undergo hydrogen bonding or intermolecular interactions with thermoplastic resins and ternary system components. This effectively reduces the resin-fiber contact angle, improves wettability, and thus enhances the interfacial adhesion strength between the carbon fiber and the resin.

[0035] 3. Improve mechanical properties and stability

[0036] Due to enhanced interfacial bonding and reduced porosity, the mechanical properties of the prepreg tape, such as interlaminar shear strength and impact toughness, are significantly improved. The material exhibits higher stability and reliability during use.

[0037] 4. Simplify processes and improve production efficiency

[0038] In a preferred embodiment of this method, the process can be completed in a single continuous step involving yarn spreading, impregnation, drying, and high-temperature roll forming, eliminating the need for secondary gluing or organic solvent recovery. This simplifies the process, reduces energy consumption, and increases production efficiency, making it suitable for industrial applications.

[0039] 5. Environmental and economic advantages

[0040] This method avoids the use of surfactants, defoamers, and some organic solvents, reducing environmental pollution and residue risks. It also lowers production costs, making the preparation of prepreg tapes more environmentally friendly and economical.

[0041] In some embodiments, the polar functional groups introduced on the carbon fiber surface by the electrochemical oxidation treatment include at least one of carboxyl, hydroxyl, and amino groups.

[0042] In this invention, the polar functional groups introduced on the carbon fiber surface by electrochemical oxidation treatment can significantly reduce the contact angle between the carbon fiber and the thermoplastic resin, improve the wettability of the resin to the fiber, thereby enhancing interfacial compatibility and adhesion, and improving the mechanical properties of the prepreg tape. Examples of the polar functional groups include carboxyl groups (–COOH), hydroxyl groups (–OH), amino groups (–NH2), carbonyl groups (–C=O), sulfonic acid groups (–SO3H), and ether groups (–O–), which can interact with the resin or dispersion components through hydrogen bonds or dipole interactions. Preferably, in some embodiments, the polar functional groups introduced on the carbon fiber surface by electrochemical oxidation treatment include at least one of carboxyl, hydroxyl, and amino groups. These three types of functional groups are easily introduced and stably exist during electrochemical oxidation, and have the strongest interaction with thermoplastic resin molecules such as polyetheretherketone, significantly improving the interfacial bonding effect.

[0043] In some embodiments, the thermoplastic resin is selected from: polyarylether ketone (PAEK), polyarylether ketone ketone (PAEKK), aromatic polyetherimide (PEI), polyarylether sulfone, polyarylether sulfide, polyamide (PA), PEBA, polyacrylate, polyolefin, polylactic acid (PLA), polyvinyl alcohol (PVA), and fluorinated polymers; and mixtures thereof.

[0044] For fluoropolymers, homopolymers of vinylidene fluoride (VDF having the formula CH2=CF2) or copolymers of VDF can be used, wherein the copolymer contains at least 50% by weight of VDF and at least one other monomer that can copolymerize with VDF. The level of VDF must exceed 80% by weight, or even better, 90% by weight, in order to provide good mechanical strength to the structural components, especially when subjected to thermal and chemical stresses. The comonomer must be a fluorinated monomer, such as vinyl fluoride.

[0045] For structural components that must withstand high temperatures, in addition to fluorinated polymers, PAEK (polyaryl ether ketone) such as poly(ether ketone) PEK, poly(ether ether ketone) PEEK, poly(ether ketone ketone) PEKK, poly(ether ketone ether ketone ketone) PEKEKK, or PA having a high glass transition temperature Tg is advantageously used according to this disclosure. Advantageously, the thermoplastic polymer is a polymer with a glass transition temperature Tg ≥ 80°C, or a semi-crystalline polymer with a melting temperature Tm ≥ 150°C.

[0046] In some embodiments, the thermoplastic resin in the dispersion has a particle size of 14 μm to 30 μm, such as 15 μm, 17 μm, 20 μm, 23 μm, 25 μm, 27 μm, and 29 μm. Controlling the particle size of the thermoplastic resin powder within the range of 14 μm to 30 μm achieves good suspension stability and dispersion uniformity in the dispersion. On the one hand, excessively large particle size leads to rapid powder settling and uneven distribution on the carbon fiber surface; on the other hand, excessively small particle size results in an excessively large specific surface area, which easily leads to agglomeration and abnormally high viscosity of the suspension, hindering continuous processing. A particle size of 14 μm to 30 μm ensures that the resin particles remain stably dispersed in the suspension for a long time and can effectively enter the gaps between carbon fiber bundles and spread evenly during impregnation, ultimately contributing to obtaining a prepreg tape with low porosity and high interfacial bonding, thereby improving the mechanical properties and stability of the product.

[0047] In some embodiments, the mass ratio of carbon fiber to thermoplastic resin in the final product is 3-4:6-7.

[0048] In this invention, the use of alcohol solutions as solvents for thermoplastic resin dispersions effectively improves the wettability and dispersibility of resin powders in the liquid phase, preventing rapid sedimentation or severe agglomeration. Simultaneously, by adjusting the viscosity and evaporation rate of the solution, uniform coating of carbon fiber tows during impregnation is ensured. The alcohol solution can be methanol, ethanol, isopropanol, butanol, polyethylene glycol, or mixtures thereof, with polyethylene glycol or ethanol solutions being preferred. Polyethylene glycol has a higher viscosity, providing better suspension stability and film uniformity, while ethanol has a lower boiling point and good volatility, facilitating rapid drying. Both solutions balance dispersion stability and process operability, making them more suitable for the continuous preparation process of this invention.

[0049] In some embodiments, the mass ratio of the thermoplastic resin to the solvent in the thermoplastic resin dispersion is (0.14~0.17):1, for example, 0.15:1 or 0.16:1. A suitable ratio range ensures that the dispersion has appropriate solids content and rheological properties.

[0050] In some embodiments, the aluminosilicate is added to the thermoplastic resin dispersion in the form of a functional aluminosilicate powder having a three-dimensional network structure, preferably with a particle size of 3 μm to 5 μm.

[0051] In some embodiments of this invention, the aluminosilicate is added to the thermoplastic resin dispersion in the form of a functional aluminosilicate powder with a three-dimensional network structure. This allows for the formation of a stable spatial framework structure in the dispersion: on the one hand, it inhibits the agglomeration and sedimentation of the thermoplastic resin powder in the liquid phase through physical support and hydrogen bonding; on the other hand, it synergistically establishes network entanglement with nanocellulose and sodium carboxymethyl cellulose during dispersion, improving the thixotropic and anti-foaming properties of the dispersion. In other embodiments, the particle size is preferably 3μm to 5μm. This ensures that it has a large specific surface area to exert the network effect without excessively increasing viscosity due to excessively fine particles, thereby ensuring that the dispersion maintains good flowability and uniformity when impregnating carbon fibers, ultimately contributing to a reduction in the porosity of the prepreg tape and an improvement in interfacial bonding.

[0052] In some embodiments, the electrolyte used in the electrochemical oxidation treatment is an aqueous solution of ammonium chloride with a concentration of 0.8 mol / L to 1.2 mol / L; the preferred treatment temperature is 28 ℃ to 37 ℃, and the treatment time is 10 min to 15 min.

[0053] In some embodiments, the molding is high-temperature roll forming; the preferred molding conditions are a temperature of 340 ℃ to 390 ℃ and a pressure of 2 MPa to 5 MPa.

[0054] In some embodiments, the drying conditions are drying at 75°C to 85°C for 300 to 400 seconds.

[0055] The embodiments of the present invention will be described in detail below with reference to examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this invention, or follow experimental manuals or conventional conditions in the art, or other experimental methods known in the art, or follow the conditions recommended by the manufacturer.

[0056] In the specific embodiments described below, the measurement parameters involving raw material components may have slight deviations within the weighing accuracy range unless otherwise specified. Temperature and time parameters are subject to acceptable deviations due to instrument testing accuracy or operational precision.

[0057] The carbon fibers used in the following examples are all domestically produced T700-12K grade carbon fibers.

[0058] Example 1

[0059] (1) Electrochemical oxidation treatment of carbon fiber tow surface: First, the carbon fiber tow passes sequentially through conductive roller 1, conductive roller 2, and conductive roller 3 into an electrolytic cell for electrochemical oxidation treatment. The roller speed is 350 rpm. The electrolytic cell uses a graphite column as the cathode and an ammonium chloride (NH4Cl) aqueous solution as the electrolyte. The electrolyte concentration is 1.0 mol / L, the electrolytic cell temperature is 33 ℃, and the electrolysis treatment time is 13 min. After electrolysis treatment, the carbon fiber tow is introduced into a cleaning tank through roller 4 and washed with deionized water to remove residual electrolyte on the surface of the carbon fiber tow. The roller speed is 350 rpm, and the water washing tank temperature is controlled at 50 ℃. Finally, the washed carbon fiber tow is collected through roller 5 to obtain carbon fiber tow with electrochemical oxidation treatment on the surface. The roller speed is 350 rpm.

[0060] (2) PEEK powder with a particle size of 14-30 μm was dispersed in a polyethylene glycol solution, with a mass ratio of PEEK powder to polyethylene glycol solution of 0.16:1; then, functional aluminosilicate powder with a particle size of 3-5 μm and a three-dimensional network structure, along with the polymer thickeners nanocellulose and sodium carboxymethyl cellulose, were added to the PEEK resin dispersion. The mixture was stirred and mixed at 60℃ and 600 rpm for 2 hours to ensure that the PEEK powder and functional aluminosilicate powder were fully dispersed and the polymer thickeners were completely dissolved, thus obtaining a thermoplastic resin suspension. The amount of nanocellulose was 1% of the mass of the dispersion, the amount of sodium carboxymethyl cellulose was 1.3% of the mass of the dispersion, and the amount of functional aluminosilicate powder was 3.2% of the amount of PEEK powder.

[0061] (3) Preparation of thermoplastic resin-based carbon fiber prepreg tape: The carbon fiber bundles after surface treatment in step 1) are dried at 80°C for 350s. After drying, the yarn is spread out and slowly immersed in the PEEK resin suspension obtained in step 2) under the action of a traction roller with a tension of 22 kg. The yarn passes through an impregnation tank, a high-temperature heat radiation plate, and a high-temperature hot press roller in sequence. After yarn spreading, impregnation, high-temperature drying and high-temperature roller pressing, a thermoplastic resin-based carbon fiber prepreg tape is obtained. The impregnation temperature is 40°C and the impregnation time is 150s. The high-temperature roller pressing temperature is 365°C and the pressure is 3.5MPa.

[0062] In step 3), the mass ratio of carbon fiber to PEEK resin is 3.5:6.5.

[0063] Example 2

[0064] (1) Electrochemical oxidation treatment of carbon fiber tow surface: First, the carbon fiber tow passes sequentially through conductive roller 1, conductive roller 2, and conductive roller 3 into an electrolytic cell for electrochemical oxidation treatment. The roller speed is 200 rpm. The electrolytic cell uses a graphite column as the cathode and an ammonium chloride (NH4Cl) aqueous solution as the electrolyte. The electrolyte concentration is 0.8 mol / L, the electrolytic cell temperature is 28 ℃, and the electrolysis treatment time is 10 min. After electrolysis treatment, the carbon fiber tow is introduced into a cleaning tank through roller 4 and washed with deionized water to remove residual electrolyte on the surface of the carbon fiber tow. The roller speed is 200 rpm, and the water washing tank temperature is controlled at 42 ℃. Finally, the washed carbon fiber tow is collected through roller 5 to obtain carbon fiber tow with electrochemical oxidation treatment on the surface. The roller speed is 200 rpm.

[0065] (2) PEEK powder with a particle size of 14-30 μm was dispersed in an ethanol solution, with a mass ratio of PEEK powder to ethanol solution of 0.14:1; then, functional aluminosilicate powder with a particle size of 3-5 μm and a three-dimensional network structure, along with the polymer thickeners nanocellulose and sodium carboxymethyl cellulose, were added to the PEEK resin dispersion. The mixture was stirred and mixed at 45 ℃ and 300 rpm for 1 h to ensure that the PEEK powder and functional aluminosilicate powder were fully dispersed and the polymer thickener was completely dissolved, thus obtaining a thermoplastic resin suspension. The amount of nanocellulose was 0.7% of the mass of the dispersion, the amount of sodium carboxymethyl cellulose was 1.1% of the mass of the dispersion, and the amount of functional aluminosilicate powder was 2.7% of the amount of PEEK powder.

[0066] (3) Preparation of thermoplastic resin-based carbon fiber prepreg tape: The carbon fiber bundles after surface treatment in step 1) are dried at 75°C for 300 s. After drying, the yarn is spread out and slowly immersed in the PEEK resin suspension obtained in step 2) under the action of a traction roller with a tension of 15 kg. The yarn passes through an impregnation tank, a high-temperature heat radiation plate, and a high-temperature hot press roller in sequence. After yarn spreading, impregnation, high-temperature drying and high-temperature roller pressing, a thermoplastic resin-based carbon fiber prepreg tape is obtained. The impregnation temperature is 25°C, the impregnation time is 120 s, the high-temperature roller pressing temperature is 340°C, and the pressure is 2 MPa.

[0067] In step 3), the mass ratio of carbon fiber to PEEK resin is 3:7.

[0068] Example 3

[0069] (1) Electrochemical oxidation treatment of carbon fiber tow surface: First, the carbon fiber tow passes sequentially through conductive roller 1, conductive roller 2, and conductive roller 3 into an electrolytic cell for electrochemical oxidation treatment. The roller speed is 500 rpm. The electrolytic cell uses a graphite column as the cathode and an ammonium chloride (NH4Cl) aqueous solution as the electrolyte. The electrolyte concentration is 1.2 mol / L, the electrolytic cell temperature is 37 ℃, and the electrolysis treatment time is 15 min. After electrolysis treatment, the carbon fiber tow is introduced into a cleaning tank through roller 4 and washed with deionized water to remove residual electrolyte on the surface of the carbon fiber tow. The roller speed is 500 rpm, and the water washing tank temperature is controlled at 60 ℃. Finally, the washed carbon fiber tow is collected through roller 5 to obtain carbon fiber tow with electrochemical oxidation treatment on the surface. The roller speed is 500 rpm.

[0070] (2) PEEK powder with a particle size of 14-30 μm was dispersed in a polyethylene glycol solution, with a mass ratio of PEEK powder to polyethylene glycol solution of 0.17:1; then, functional aluminosilicate powder with a particle size of 3-5 μm and a three-dimensional network structure, along with the polymer thickeners nanocellulose and sodium carboxymethyl cellulose, were added to the PEEK resin dispersion. The mixture was stirred and mixed at 70 °C and 1000 rpm for 3 h to ensure that the PEEK powder and functional aluminosilicate powder were fully dispersed and the polymer thickener was completely dissolved, thus obtaining a thermoplastic resin suspension. The amount of nanocellulose was 1.2% of the mass of the dispersion, the amount of sodium carboxymethyl cellulose was 1.5% of the mass of the dispersion, and the amount of functional aluminosilicate powder was 3.6% of the amount of PEEK powder.

[0071] (3) Preparation of thermoplastic resin-based carbon fiber prepreg tape: The carbon fiber bundles after surface treatment in step 1) are dried at 85°C for 400 s. After drying, the yarn is spread out and slowly immersed in the PEEK resin suspension obtained in step 2) under the action of a traction roller with a tension of 30 kg. The yarn passes through an impregnation tank, a high-temperature heat radiation plate, and a high-temperature hot press roller in sequence. After spreading, impregnation, high-temperature drying and high-temperature rolling, a thermoplastic resin-based carbon fiber prepreg tape is obtained. The impregnation temperature is 60 ℃, the impregnation time is 180 s, the high-temperature rolling temperature is 390 ℃, and the pressure is 5 MPa.

[0072] In step 3), the mass ratio of carbon fiber to PEEK resin is 4:6.

[0073] Experimental Example

[0074] To investigate the effect of introducing polar functional groups into the electrochemical oxidation system and the ternary synergistic dispersion system, this invention sets up different groups (route 1-route 4) for verification.

[0075] Route 1 is also known as Example 1.

[0076] Route 2 (to the aluminosilicate group)

[0077] This route is basically the same as that in Experiment 1, but functional aluminosilicates are not added to the dispersion; only nanocellulose and sodium carboxymethyl cellulose are retained.

[0078] Route 3 (Table Performance Baseline Group)

[0079] This approach introduces conventional defoamers and surfactants (such as alkylphenol polyoxyethylene ethers and dimethylformamide) during suspension preparation, without adding aluminosilicates.

[0080] Route 4 (Polar Surface Verification Group)

[0081] This route does not involve electrochemical oxidation of the carbon fiber bundles; otherwise, it is the same as in Experimental Example 1.

[0082] Properties of impregnation strips prepared by different routes

[0083] Group Porosity (%) Interlaminar shear strength / MPa Dynamic contact angle / ° Tensile strength / MPa Route 1 ≤2% 110.3 61±2 2300 Route 2 2.5%-3.2% 95.7 71±2 2070 Route 3 ≥4% 91.6 78±3 1950 Route 4 5%-7% 87.6 85±1 1800

[0084] Note: The testing methods for each performance indicator are as follows.

[0085] Porosity: GB / T 3365-2008 "Test Methods for Density and Porosity of Carbon Fiber Reinforced Plastics"

[0086] Interlaminar shear strength: GB / T 1458-2008 "Determination of interlaminar shear strength of fiber-reinforced plastics by short beam method"

[0087] Dynamic contact angle: GB / T 30693-2014 "Methods for measuring contact angle of solid surfaces - Dropping method"

[0088] Tensile strength: GB / T 3354-2014 "Test Method for Tensile Properties of Fiber Reinforced Plastic Composites"

[0089] The experimental results show that Route 1 (Example 1, i.e., the invention group) proposed in this invention is significantly superior to the control group in terms of porosity, interlaminar shear strength, interfacial wettability, and overall mechanical properties. Its porosity is controlled at ≤2%, the interlaminar shear strength reaches 110.3 MPa, and the dynamic contact angle is only 61±2°. This indicates that without the use of surfactants and defoamers, the ternary system (aluminosilicate, nanocellulose, sodium carboxymethyl cellulose) combined with electrochemical oxidation treatment of the carbon fiber surface can achieve stable dispersion and uniform wetting, resulting in a dense and high-performance prepreg tape.

[0090] In contrast, although Route 2 (aluminosilicate group) also contains nanocellulose and sodium carboxymethyl cellulose, the porosity of the prepreg tape increases to 2.5%–3.2% due to the lack of the spatial network skeleton effect of aluminosilicate, the interlaminar shear strength decreases to 95.7 MPa, and the contact angle also increases significantly. This indicates that aluminosilicate plays an irreplaceable role in preventing powder agglomeration, inhibiting bubble formation, and improving the uniformity of resin distribution on the fiber surface.

[0091] Route 3 (surfactant baseline group) maintains dispersion through traditional surfactants and defoamers, but its prepreg has a porosity of ≥4%, interfacial bonding force drops to 91.6 MPa, and tensile strength is only 1950 MPa. This shows that although the surfactant system can reduce the contact angle to some extent, the porosity problem and interfacial defects caused by residues limit the overall performance. This indicates that the "surfactant-free / defoamer-free" system of the present invention is superior to conventional technical routes in terms of both effect and stability.

[0092] Route 4 (without electrochemical oxidation) yielded the worst results, with porosity increasing to 5%–7%, interlaminar shear strength at only 87.6 MPa, and contact angle as high as 85±1°. This indicates that without polarization modification of the carbon fiber bundles, the ternary system struggles to form good wetting and interfacial interactions on the fiber surface, ultimately leading to a loose prepreg structure and decreased performance.

[0093] Based on the above comparative results, it can be confirmed that the combination of electrochemical oxidation introducing polar functional groups and the ternary synergistic dispersion system is the key to achieving the technical effects of this invention. The former improves the wettability of the fiber surface, while the latter stabilizes the dispersion of resin powder and suppresses bubbles; the technical effect achieved by the combination of the two is significantly better than using either measure alone. The combined effect not only avoids the use of surfactants and defoamers, reducing environmental risks and process complexity, but also significantly improves the porosity and interfacial bonding performance of the prepreg tape, resulting in excellent mechanical properties of the final product.

[0094] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for preparing thermoplastic resin-based carbon fiber prepreg tape, characterized in that, Includes the following steps: Electrochemical oxidation treatment is performed on carbon fiber bundles to introduce polar functional groups on their surface. The obtained carbon fiber bundles were dried and spread out, then impregnated in a thermoplastic resin dispersion, and subsequently dried and shaped to obtain a thermoplastic resin-based carbon fiber prepreg tape. The thermoplastic resin dispersion is a thermoplastic resin solution containing aluminosilicate, nanocellulose, and sodium carboxymethyl cellulose, and the dispersion does not contain surfactants or defoamers; the amount of aluminosilicate is 2.7 w / w % to 3.6 w / w % of the mass of the thermoplastic resin, the amount of nanocellulose is 0.7 w / w % to 1.2 w / w % of the mass of the dispersion, and the amount of sodium carboxymethyl cellulose is 1.1 w / w % to 1.5 w / w % of the mass of the dispersion.

2. The preparation method according to claim 1, characterized in that, The electrochemical oxidation treatment introduces polar functional groups on the carbon fiber surface, including at least one of carboxyl, hydroxyl, and amino groups.

3. The preparation method according to claim 1, characterized in that, The thermoplastic resin is selected from: polyaryletherketone (preferably polyetheretherketone), polyaryletherketoneketone, aromatic polyetherimide, polyarylether sulfone, polyarylether sulfide, polyamide, PEBA, polyacrylate, polyolefin, polylactic acid, polyvinyl alcohol and fluorinated polymers; and mixtures thereof.

4. The preparation method according to claim 3, characterized in that, In the thermoplastic resin dispersion, the particle size of the thermoplastic resin is 14μm to 30μm.

5. The preparation method according to any one of claims 1 to 4, characterized in that, The solvent for the thermoplastic resin dispersion is an alcohol solution, preferably a polyethylene glycol solution or an ethanol solution.

6. The preparation method according to claim 5, characterized in that, In the thermoplastic resin dispersion, the mass ratio of the thermoplastic resin to the solvent is (0.14~0.17):

1.

7. The preparation method according to any one of claims 1 to 4, 6, characterized in that, The aluminosilicate is added to the thermoplastic resin dispersion in the form of a functional aluminosilicate powder with a three-dimensional network structure, and its particle size is preferably 3μm to 5μm.

8. The preparation method according to any one of claims 1 to 4, 6, characterized in that, The electrolyte used in the electrochemical oxidation treatment is an aqueous solution of ammonium chloride with a concentration of 0.8 mol / L to 1.2 mol / L; the preferred treatment temperature is 28 ℃ to 37 ℃, and the treatment time is 10 min to 15 min.

9. The preparation method according to any one of claims 1 to 4, 6, characterized in that, The molding process is high-temperature roll forming; the preferred molding conditions are a temperature of 340 ℃~390 ℃ and a pressure of 2 MPa~5 MPa.

10. The preparation method according to any one of claims 1 to 4, 6, characterized in that, The drying conditions are 75℃~85℃ for 300 s~400 s.

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