Preparation method for manufacturing 3D printing continuous wire by using regenerated carbon fibers

Abstract

The invention discloses a preparation method for manufacturing a 3D printing continuous wire rod by using regenerated carbon fibers, and aims to efficiently recycle carbon fiber reinforced material wastes in an environment-friendly manner. The method comprises the following steps: providing a regenerated carbon fiber aggregate; the regenerated carbon fiber aggregates are connected end to end by using an adhesive so as to ensure that a plurality of aggregates form a whole in the preparation process and prevent a single bundle of aggregates from being separated from equipment; and presoaking the connected regenerated carbon fiber aggregate and the resin mixture through a presoaking machine for later use. The regenerated carbon fiber long fiber does not need to be smashed, the continuity and excellent mechanical property of the regenerated carbon fiber long fiber are reserved, the tensile strength and the elongation at break of the 3D printing wire rod are remarkably improved, and remarkable economic and environmental benefits are achieved. The method is suitable for the fields of aerospace, wind power blades, automobile manufacturing and the like, and the requirements of high-strength and high-modulus additive manufacturing are met.

Description

Technical Field

[0001] The present invention relates to the technical field of recycled composite materials, and in particular to a method for preparing 3D printing continuous wire by utilizing recycled carbon fibers. Background Art

[0002] In recent years, carbon fiber reinforced materials (CFRP) have been widely used in aerospace, wind turbine blades, sports and leisure, automobiles, pressure vessels and other fields due to their low density, high strength and modulus, good corrosion resistance and weather resistance. Components made of carbon fiber reinforced materials will produce 30%-50% scraps during production. At the same time, a large number of CFRP components will reach the end of their service life and be scrapped over time. The amount of CFRP waste is increasing, resulting in a large amount of resource waste. At the same time, these wastes are extremely difficult to decompose due to the extremely high corrosion resistance and weather resistance of the carbon fiber, causing great pollution to the natural environment.

[0003] There have been studies at home and abroad on the recovery of carbon fiber from CFRP waste through thermal cracking, microwave, chemical dissolution and other technologies, and industrialization has begun. Among them, the thermal cracking method has been able to recycle CFRP in batches, and the maximum fiber length of a single recovery can reach 2 meters. Recycled carbon fiber is usually used for downgrading applications, such as making short fibers of about 5 mm to 7 mm, carbon fiber felt and resin composites, carbon fiber granules for injection molding products, or as 3D printing additive materials. However, these application scenarios often require the long fibers to be crushed into short fibers and dispersed, which not only increases additional processing costs, but also significantly reduces the mechanical properties of carbon fiber.

[0004] For example, CN106079436A discloses a 3D printed continuous fiber reinforced composite material recycling and remanufacturing method, which includes a 3D printed continuous fiber reinforced composite material recycling device, which can re-compound the recycled composite material prepreg with the polymer matrix material for secondary printing, thereby realizing the efficient, low-cost, and high-performance recycling and reuse of continuous fiber reinforced thermoplastic materials.

[0005] For example, CN112092238A discloses a 3D printing wire of recycled carbon fiber reinforced polyamide and its preparation method and application, which includes crushing and granulating the recycled carbon fiber and polyamide, and extruding the 3D printing wire in a single-screw extruder. The recycled carbon fiber used is short fibers after crushing, and the fiber content in the material is less than 30%, resulting in low mechanical properties of the prepared 3D printing wire.

[0006] The above methods all rely on additional operations such as crushing and chopping of recycled carbon fibers, which significantly reduce the length and mechanical properties of the carbon fibers. Therefore, it is necessary to provide a preparation method and carbon fiber products prepared therefrom that can effectively utilize recycled carbon fibers and maintain their longer fiber length and excellent mechanical properties without additional operations, so as to meet the needs of applications such as high-performance 3D printing. Summary of the invention

[0007] In response to the above technical problems, a preparation method for 3D printing continuous wire using recycled carbon fiber is provided. The present invention directly utilizes the recycled carbon fiber aggregate without additional chopping or shuffling, adopts long fibers with a length of 1m-2m, and connects the fiber aggregate end to end in combination with an appropriate adhesive to prepare a continuous 3D printing wire. The 3D printing wire can be directly applied to existing 3D printing equipment, which not only significantly improves the utilization rate of recycled carbon fiber, but also expands its application scenarios in the field of additive manufacturing. The wire prepared by this method retains the long fiber structure of the recycled carbon fiber, ensures the high strength and excellent mechanical properties of the 3D printed products, thereby effectively solving the problem of performance degradation due to fiber crushing in traditional recycling methods.

[0008] The technical means adopted by the present invention are as follows:

[0009] A method for preparing 3D printing continuous wire using recycled carbon fiber, comprising the following steps:

[0010] S1. Providing a regenerated carbon fiber aggregate, wherein the regenerated carbon fiber aggregate is composed of a plurality of regenerated carbon fiber filaments with a length of 100 mm to 2000 mm and a diameter of 1 mm to 5 mm;

[0011] S2. Use adhesive to connect the ends of the regenerated carbon fiber assemblies, the adhesive is located between two groups of regenerated carbon fiber assemblies, the length of the adhesive is 5mm-15mm, the thickness is 0.1mm-1mm, and the width is the same as the width of the regenerated carbon fiber assemblies. The adhesive can ensure that during the process of making 3D printing wires, several regenerated carbon fiber assemblies form a whole to prevent a single bundle of assemblies from escaping from the equipment;

[0012] S3. Pre-impregnate the above-mentioned regenerated carbon fiber aggregate and resin mixture through a pre-impregnation machine to form a composite prepreg tape suitable for 3D printing. The pre-impregnation composite includes placing the regenerated carbon fiber aggregate in the middle, covering the upper and lower surfaces of the regenerated carbon fiber aggregate with the resin mixture, and infiltrating the resin into the gaps in the carbon fibers through a hot pressing process; the resin content of the 3D printing prepreg tape is 30%-70%.

[0013] Furthermore, the adhesive is selected from thermoplastic resin or thermosetting resin.

[0014] Furthermore, the thermosetting resin is selected from epoxy resin or phenolic resin; the thermoplastic resin is selected from polyvinyl acetal, perchlorethylene resin or polyamide.

[0015] Furthermore, the resin mixture is selected from thermoplastic resin or thermosetting resin, the thermoplastic resin is selected from at least one of PLA, PA, ABS, PPS, PC or PEEK; and the thermosetting resin is selected from epoxy resin.

[0016] Furthermore, the prepreg process is carried out by a prepreg machine under certain temperature and pressure conditions to ensure that the resin fully penetrates and combines with the recycled carbon fiber aggregate.

[0017] Furthermore, the regenerated carbon fiber aggregate is surface treated before prepreg to improve the bonding performance with the resin mixture.

[0018] Furthermore, in step S3, the temperature range of the hot pressing process is 100° C.-200° C., and the pressure range is 1 MPa-5 MPa.

[0019] Furthermore, when the adhesive is used to connect the regenerated carbon fiber aggregate, the amount of adhesive used is 0.5g-2g of adhesive per meter of the regenerated carbon fiber aggregate.

[0020] Furthermore, the regenerated carbon fiber filaments are pre-cleaned and dried to remove impurities and moisture to ensure the quality of the composite material.

[0021] Furthermore, after the preparation of the 3D printing prepreg tape, it is cooled and cut to form a continuous wire suitable for 3D printing equipment.

[0022] Compared with the prior art, the present invention has the following significant advantages:

[0023] 1. Efficient use of recycled carbon fiber resources: The carbon fiber used in the present invention comes from recycled carbon fiber, which can effectively utilize CFRP waste or carbon fiber prepreg waste. This not only reduces the pollution of carbon fiber waste to the environment and reduces resource waste, but also opens up the application scenarios of recycled carbon fiber in the field of additive manufacturing. By converting discarded CFRP materials into high-performance 3D printing wires, the recycling of resources is achieved, which meets the needs of sustainable development.

[0024] 2. Retain the continuous long fiber structure of carbon fiber: The present invention directly utilizes the continuous long fibers in the recycled carbon fiber assembly without additional shredding or shuffling. This process eliminates the steps of fiber crushing and dispersion in traditional recycling methods, reducing production costs. At the same time, the original structure of the long fibers is retained, so that the mechanical properties of the recycled carbon fiber can be fully utilized, providing raw materials with better performance to meet the needs of high-strength and high-modulus applications.

[0025] 3. Improve the mechanical properties of 3D printing wires: 3D printing wires made of continuous long fibers have better mechanical properties than short fiber reinforced wires. Long fibers can more effectively transfer stress during the printing process, improving the overall strength and toughness of the product. In addition, the use of adhesives to connect the recycled carbon fiber aggregates end to end ensures the continuity and integrity of the wires, avoiding the problem of a single bundle of fibers falling out of the equipment, thereby further improving the quality and reliability of printed products.

[0026] 4. Diversified resin selection and optimized composite process: In the preparation process of the present invention, a variety of thermoplastic resins and thermosetting resins can be selected as adhesives and resin mixtures, such as PLA, PA, ABS, PPS, PC, PEEK, epoxy resin, etc. This diverse resin selection enables the prepared 3D printing wire to adapt to different printing needs and application environments. At the same time, through the pre-impregnation machine and hot pressing process, the resin fully penetrates into the gaps of the carbon fiber, ensuring the high adhesion and uniformity of the composite material, and improving the overall performance of the wire and the printing effect.

[0027] 5. Optimized preparation process parameters: In the preparation process, the present invention clearly specifies the length and diameter of the recycled carbon fiber aggregate, as well as the length, thickness and width of the adhesive. The setting of these specific parameters ensures the controllability of the preparation process and the consistency of the wire quality. In addition, the temperature range and pressure range of the hot pressing process in the prepreg composite step further optimize the bonding effect between the resin and the carbon fiber, increase the resin content of the prepreg tape, and thus enhance the comprehensive performance of the 3D printing wire.

[0028] In summary, the present invention avoids the complicated steps of fiber crushing and dispersion in the traditional method by optimizing the processing flow of recycled carbon fiber, thereby reducing equipment investment and operating costs. At the same time, the use of prepreg machines for composite processing improves production efficiency, shortens the preparation cycle, and significantly enhances the mechanical properties and quality of 3D printed products. These improvements not only reduce production costs, but also improve the sustainability and economic benefits of production. Based on this, the technical solution of the present invention has broad application prospects and significant economic and environmental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0030] Figure 1 This is a schematic diagram of a regenerated carbon fiber aggregate in a method for preparing 3D printing continuous wire using regenerated carbon fiber according to the present invention.

[0031] Figure 2 This is a schematic diagram of a regenerated carbon fiber aggregate being bonded by an adhesive in a preparation method for making 3D printing continuous wire using regenerated carbon fiber according to the present invention. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Example 1

[0034] The present invention provides a method for preparing a 3D printing continuous wire using recycled carbon fiber, comprising the following steps:

[0035] S1: Providing recycled carbon fiber aggregate (such as Figure 1 As shown), recycled carbon fiber filaments with a length of 1500 mm and a diameter of 3 mm are selected, and each assembly consists of 50 filaments.

[0036] S2: Use epoxy resin as an adhesive to connect the two recycled carbon fiber assemblies end to end (such as Figure 2 As shown), the length of the adhesive is set to 10 mm, the thickness is 0.5 mm, and the width is the same as that of the carbon fiber aggregate.

[0037] S3: The connected recycled carbon fiber aggregate and epoxy resin mixture are pre-impregnated by a pre-impregnation machine, using a hot pressing process, with the temperature set to 150°C and the pressure set to 3MPa, so that the resin fully penetrates into the gaps of the carbon fibers. The resin content of the pre-impregnated tape is controlled at 50%.

[0038] S4: The prepreg tape is cooled and cut to form a continuous wire suitable for 3D printing equipment.

[0039] Example 2

[0040] The present invention provides a method for preparing a 3D printing continuous wire using recycled carbon fiber, comprising the following steps:

[0041] S1: Regenerated carbon fiber filaments with a length of 1200 mm and a diameter of 2 mm are provided, and each assembly consists of 40 filaments.

[0042] S2: Use polyvinyl acetal (PVA) as an adhesive to connect two recycled carbon fiber assemblies end to end. The adhesive is 8 mm long, 0.3 mm thick, and has the same width as the carbon fiber assemblies.

[0043] S3: The connected recycled carbon fiber aggregate and the PLA resin mixture are pre-impregnated by a pre-impregnation machine, using a hot pressing process, with the temperature set at 180°C and the pressure at 4MPa to allow the resin to fully penetrate. The resin content of the pre-impregnated tape is 60%.

[0044] S4: The prepreg tape is cooled and cut to make continuous filament for 3D printing.

[0045] Example 3

[0046] The present invention provides a method for preparing a 3D printing continuous wire using recycled carbon fiber, comprising the following steps:

[0047] S1: Regenerated carbon fiber filaments with a length of 2000 mm and a diameter of 4 mm are provided, and each assembly consists of 60 filaments.

[0048] S2: Use phenolic resin as an adhesive to connect the two recycled carbon fiber assemblies end to end. The length of the adhesive is 12 mm, the thickness is 0.8 mm, and the width is the same as the carbon fiber assembly.

[0049] S3: The connected recycled carbon fiber aggregate and the PEEK resin mixture are pre-impregnated by a pre-impregnation machine, using a hot pressing process, with the temperature set at 200°C and the pressure at 5MPa to allow the resin to fully penetrate. The resin content of the pre-impregnated tape is 70%.

[0050] S4: The prepreg tape is cooled and cut to make continuous filament for 3D printing.

[0051] Example 4

[0052] The present invention provides a method for preparing a 3D printing continuous wire using recycled carbon fiber, comprising the following steps:

[0053] S1: Regenerated carbon fiber filaments with a length of 1000 mm and a diameter of 1.5 mm are provided, and each assembly consists of 30 filaments.

[0054] S2: Use polyamide as adhesive to connect two recycled carbon fiber assemblies end to end. The adhesive is 6 mm long, 0.2 mm thick, and the same width as the carbon fiber assemblies.

[0055] S3: The connected recycled carbon fiber aggregate and ABS resin mixture are pre-impregnated by a pre-impregnation machine, using a hot pressing process, with the temperature set at 160°C and the pressure set at 2MPa to allow the resin to fully penetrate. The resin content of the pre-impregnated tape is 40%.

[0056] S4: The prepreg tape is cooled and cut to make continuous filament for 3D printing.

[0057] Comparative Example 1: Traditional short fiber reinforced 3D printing filament

[0058] The preparation method comprises:

[0059] Fiber processing: The recycled carbon fiber filaments are crushed into short fibers with a length of 5 mm.

[0060] Blending: Blend short fibers with polyamide, with the fiber content controlled at 25%.

[0061] Extrusion: 3D printing filaments are prepared by a single screw extruder.

[0062] Comparative Example 2: Traditional prepreg reinforced 3D printing filament

[0063] The preparation method comprises:

[0064] Prepreg processing: Carbon fiber is recycled using thermal cracking to prepare prepreg.

[0065] Extrusion: 3D printing filaments were prepared by a single screw extruder with a resin content of 30%.

[0066] Mechanical properties tests were introduced for Examples 1-4 and Comparative Examples 1-2, using industry standard tensile tests and elongation at break tests, which complied with ISO 527 (plastic tensile properties test method) and ASTM D3039 (composite material tensile test method). The specific test results are shown in the following table:

[0067] Table 1 Comparison of mechanical properties of 3D printing wires prepared by different methods

[0068]

[0069] Through the analysis of the experimental data of specific examples 1-4 and comparative examples 1-2, it can be clearly seen that the method of directly preparing continuous long fiber reinforced 3D printing wire using recycled carbon fiber provided by the present invention has significantly improved mechanical properties compared with traditional short fiber reinforced and prepreg reinforced wires. Specifically, it is manifested as follows:

[0070] 1. The tensile strength is significantly improved: The tensile strength of Examples 1-4 is higher than that of Comparative Examples 1 and 2, with the highest reaching 520 MPa, indicating that the application of continuous long fibers effectively enhances the tensile strength of the wire.

[0071] 2. Improved elongation at break: The elongation at break of Examples 1-4 is higher than that of Comparative Examples 1 and 2, with the highest reaching 3.2%, indicating that the wire has better ductility and toughness when subjected to stress.

[0072] 3. Maintaining the original fiber structure: The present invention avoids the fiber crushing process by directly utilizing 1- to 2-meter long fibers, retains the continuity and long fiber structure of the carbon fibers, and ensures the high performance of the composite material.

[0073] 4. Diversified resin selection and optimized process: By selecting different types of thermoplastic and thermosetting resins and optimizing prepreg and hot pressing process parameters, the prepared 3D printing filaments can meet different application requirements and further improve the comprehensive performance of the filaments.

[0074] 4. Optimized resin content control: In each embodiment of the present invention, by controlling the resin content between 40% and 70%, the best composite effect of resin and carbon fiber is achieved, and the mechanical properties of the wire are enhanced. At the same time, the flexible adjustment of the resin content enables the wire to adapt to different printing requirements and application environments.

[0075] 5. Environmental protection and economic benefits: The method of the present invention effectively utilizes CFRP waste, reduces environmental pollution, reduces production costs, realizes the recycling of resources, and meets the requirements of sustainable development.

[0076] In summary, the present invention provides an efficient, environmentally friendly and economical method for preparing recycled carbon fiber 3D printing continuous wire. By retaining the long fiber structure of carbon fiber, optimizing the selection and dosage of adhesive, controlling the prepreg process parameters and resin content, the mechanical properties of 3D printing wire are significantly improved, and the application scenarios of recycled carbon fiber are expanded. It has broad market prospects and significant technical advantages.

[0077] The above embodiments are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, a person of ordinary skill in the art should understand that any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing 3D printing continuous wire using recycled carbon fiber, characterized in that: The following steps are involved: S1. Providing a regenerated carbon fiber aggregate, wherein the regenerated carbon fiber aggregate is composed of a plurality of regenerated carbon fiber filaments with a length of 100 mm to 2000 mm and a diameter of 1 mm to 5 mm; S2. Use adhesive to connect the ends of the regenerated carbon fiber assemblies, the adhesive is located between two groups of regenerated carbon fiber assemblies, the length of the adhesive is 5mm-15mm, the thickness is 0.1mm-1mm, and the width is the same as the width of the regenerated carbon fiber assemblies. The adhesive can ensure that during the process of making 3D printing wires, several regenerated carbon fiber assemblies form a whole to prevent a single bundle of assemblies from escaping from the equipment; S3. Pre-impregnate the above-mentioned regenerated carbon fiber aggregate and resin mixture through a pre-impregnation machine to form a composite prepreg tape suitable for 3D printing. The pre-impregnation composite includes placing the regenerated carbon fiber aggregate in the middle, covering the upper and lower surfaces of the regenerated carbon fiber aggregate with the resin mixture, and infiltrating the resin into the gaps in the carbon fibers through a hot pressing process; the resin content of the 3D printing prepreg tape is 30%-70%.

2. The preparation method according to claim 1, characterized in that: The adhesive is selected from thermoplastic resin or thermosetting resin.

3. The preparation method according to claim 2, characterized in that: The thermosetting resin is selected from epoxy resin or phenolic resin; the thermoplastic resin is selected from polyvinyl acetal, perchlorethylene resin or polyamide.

4. The preparation method according to claim 1, characterized in that: The resin mixture is selected from thermoplastic resin or thermosetting resin, the thermoplastic resin is selected from at least one of PLA, PA, ABS, PPS, PC or PEEK; the thermosetting resin is selected from epoxy resin.

5. The preparation method according to claim 1, characterized in that: The prepreg process is performed by a prepreg machine under certain temperature and pressure conditions to ensure that the resin fully penetrates and combines with the recycled carbon fiber aggregate.

6. The preparation method according to claim 1, characterized in that: The regenerated carbon fiber aggregate is surface treated before pre-preg to improve the bonding performance with the resin mixture.

7. The preparation method according to claim 1, characterized in that: In step S3, the temperature range of the hot pressing process is 100° C.-200° C., and the pressure range is 1 MPa-5 MPa.

8. The preparation method according to claim 1, characterized in that: When the adhesive is used to connect the regenerated carbon fiber aggregate, the amount of adhesive used is 0.5g-2g of adhesive per meter of the regenerated carbon fiber aggregate.

9. The preparation method according to claim 1, characterized in that: The recycled carbon fiber filaments are pre-cleaned and dried to remove impurities and moisture to ensure the quality of the composite material.

10. The preparation method according to claim 1, characterized in that: After the 3D printing prepreg is prepared, it is cooled and cut to form a continuous wire suitable for 3D printing equipment.

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