Reinforced composite material and application thereof in preparation of continuous carbon fiber reinforced 3D printing wire material

Abstract

The invention belongs to the field of high polymer materials and thermoplastic composite materials, and discloses a reinforced composite material and application of the reinforced composite material in preparation of continuous carbon fiber reinforced 3D printing wire materials, the composite material comprises the following raw materials: PA66, PA610, an antioxidant, TAF and a performance additive, raw materials are subjected to mechanical mixing and melt blending extrusion, then an obtained composite material is compounded with continuous carbon fibers through a continuous carbon fiber impregnation process, and the continuous carbon fiber reinforced composite material 3D printing wire can be obtained through mouth mold impregnation, traction and cooling. On one hand, the strength of the printing wire is greatly improved compared with that of a pure resin 3D printing wire which is not reinforced by continuous carbon fibers, the toughness is remarkably improved, on the other hand, the compounding effect of the modified composite material and the continuous carbon fibers is good, the manufacturability is remarkably improved, and the wire breakage rate is remarkably reduced; through tests, smooth printing can be achieved, and the method can be used for scientific research and industrial production of 3D printing of thermoplastic composite materials and engineering plastics.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of high polymer materials and thermoplastic composite materials, and discloses a reinforced composite material and application thereof in preparation of continuous carbon fiber reinforced 3D printing filaments. BACKGROUND

[0002] 3D printing technology (additive manufacturing) is a revolutionary manufacturing technology based on digital models, which can realize free forming of complex structures through layer-by-layer accumulation, breaking through the design and manufacturing limitations of traditional processing methods. With the advantages of flexible design space, easy processing of complex structures, accurate entity replication, etc., 3D printing technology has attracted much attention. As an emerging technology, the characteristics of 3D printing "design and manufacturing integration" can not only meet the personalized manufacturing needs of thousands of parts in the traditional manufacturing industry, but also reduce the connection between parts, simplify the assembly process of parts, improve process stability and manufacturing efficiency, and is an indispensable manufacturing method in the future intelligent manufacturing field, and is known as "manufacturing technology with industrial revolution significance". 3D printing technology can quickly manufacture without molds, effectively shortening the product development cycle, and is particularly suitable for small-batch customized production, opening up a new era for the design and manufacturing of high-performance, low-cost complex composite structures.

[0003] Combining 3D printing technology with fiber reinforced composite material process is expected to solve the problems of complex forming process, secondary processing, long production cycle, use of molds, high cost, etc. in traditional composite material manufacturing. For thermoplastic composite material 3D printing (belonging to the cross field of intelligent manufacturing and composite material processing), the 3D printing filament materials at present are mostly modified engineering plastic filaments or engineering plastic powders, and common materials include acrylonitrile-butadiene-styrene copolymer (ABS), polylactic acid (PLA), nylon (PA), high-impact polystyrene (HIPS), polycarbonate (PC), etc. Among them, nylon material has high strength, good toughness, self-lubricating and wear resistance, etc., making nylon printing filament a kind of printing material with excellent comprehensive performance, and making additive manufacturing products meet the lightweight and fine demand.

[0004] PA66 is a kind of semi-aromatic polyamide, which has excellent mechanical strength, heat resistance and wear resistance, and is widely used in aerospace, weapon equipment, automobile parts, electronic appliances, etc. However, the amide bond (-CONH-) in the molecular chain of PA66 has strong polarity, which is easy to form hydrogen bond with water molecules and then cause defects in the printed product due to material water absorption; under standard environmental conditions (23℃ / 50%RH), the equilibrium water absorption rate can reach 2.5-3.0%; this water absorption characteristic will cause the following problems: (1) the material expands in size after absorbing water, affecting the dimensional stability of the product; (2) the rigidity and high-temperature performance of the nylon material will be significantly reduced after absorbing water; (3) when used in a hot and humid environment for a long time, the mechanical strength of the nylon material will decrease due to hydrolytic degradation; (4) compared with traditional forming processes, the 3D printing process lacks a drying and water removal step, and the dehydration capacity of the printing chamber and the storage bin is low at the present stage. The increase in the water content of the raw material will increase the process forming difficulty of the product and reduce the strength of the printed structural part.

[0005] Therefore, how to overcome the above-mentioned defects of PA66 and better apply it to high-performance composite 3D printing has become the focus of the inventors' research. The prior art has a scheme of modifying PA66 with carbon fiber material, but the reinforcing body used is short fiber, and the morphology of carbon fiber in the composite material is not continuous phase but cut off, which has limited effect on the modification and reinforcement of PA66, and the unidirectional strength of the product prepared is not significantly improved. SUMMARY

[0006] The present application provides a reinforced composite material and its application in the preparation of continuous carbon fiber reinforced 3D printing filament, which overcomes the above-mentioned technical problems. The composite material raw material includes PA66, PA610, antioxidant, TAF and modification aid, etc. The above-mentioned raw materials are mechanically mixed, melt blended and extruded, and then the obtained composite material is compounded with continuous carbon fiber through a continuous carbon fiber impregnation process. The continuous carbon fiber reinforced PA66 / PA610 composite material 3D printing filament is obtained through die impregnation and traction cooling. The strength of the 3D printing filament is greatly improved compared with the 3D printing filament without using continuous fiber reinforced resin, the toughness is significantly improved and normal printing is not affected. Compared with the composite material reinforced with short fibers, the morphology of carbon fiber in the composite material is continuous phase, and the obtained continuous carbon fiber reinforced thermoplastic composite material can be applied in the 3D printing of high-performance engineering plastics, and the unidirectional strength of the manufactured product is much higher than that of traditional 3D printed engineering plastics, so it can be used in the industrialized production of thermoplastic composite materials and engineering plastics 3D printing.

[0007] The inventive concept of the present application is as follows: the reinforcing material adopted is continuous carbon fiber, which has extremely high specific strength and specific modulus, and the density is only one fourth of that of steel, but the strength can reach more than 5 times that of steel, and is one of the most important light and high-strength fiber materials at present. The carbon fiber also has excellent heat resistance, creep resistance and dimensional stability, and can maintain stable performance even in harsh environments such as high temperature and high load, and the corrosion resistance and fatigue resistance of the carbon fiber are also very outstanding, which can effectively prolong the service life of the composite structure under actual working conditions. Compared with the prior art, the carbon fiber adopted in the present application is continuous carbon fiber, which can not only significantly improve the tensile strength, bending modulus and impact toughness of the printed part, but also realize the structure and function customization of on-demand reinforcement through the controllability of the direction. The programmability of such performance makes the carbon fiber reinforced composite material very suitable for the development of customized products with high requirements for mechanical properties, structural optimization and weight reduction.

[0008] Corresponding to the thermoplastic matrix system, the inventors selected a PA66 / PA610 thermoplastic matrix system to construct a continuous carbon fiber reinforced composite material, and this combination not only can significantly enhance the comprehensive mechanical properties of the composite material, but also improve the stability and practicality in the 3D printing forming process, which has important significance for promoting the engineering application of high-performance additive manufacturing materials. Through formula modification, melt impregnation and other processes, the inventors reduce the water absorption of the material on the basis of maintaining the excellent performance of PA66, improve the printing process and improve the mechanical strength of the printed part.

[0009] The specific technical solutions of the present application are as follows: A reinforced composite material, which comprises, by weight: 60-80 parts of PA66, 15-35 parts of PA610, 3.5-4.5 parts of a nylon toughening agent, 0.5-1.5 parts of a coupling agent, 1-3 parts of an antioxidant, and 1-2 parts of a glass fiber exposure prevention agent TAF.

[0010] More preferably, the composition of the composite material is as follows: 65-75 parts of PA66, 20-30 parts of PA610, 3.5-4.5 parts of a nylon toughening agent, 0.5-1.5 parts of a coupling agent, 1-2 parts of an antioxidant, and 1-2 parts of a glass fiber exposure prevention agent TAF.

[0011] In the above scheme, preferably, the viscosity of the PA66 is ≤2.50; and the viscosity of the PA610 is ≤2.20. The inventor adds the PA610 resin of the above ratio in the PA66, the PA610 resin is obtained by condensation of hexanediamine and succinic acid, and has more hydrophobic groups and less hydrophilic groups in the molecular chain. After compounding with the PA66, the density of the amide groups in the PA66 / PA610 material is reduced, the water absorption problem caused by the intermolecular hydrogen bond is reduced, and the permeability is also reduced. Compared with the pure PA66 printing wire material, the water absorption is reduced, the dimensional stability is improved, and the normal printing is not affected.

[0012] In addition, preferably, the nylon toughening agent is selected from maleic anhydride grafted polyolefin elastomer (POE-g-MAH) or maleic anhydride grafted EPDM (EPDM-g-MAH), and preferably POE-g-MAH is used. The coupling agent is selected from silane coupling agent or titanate coupling agent, and preferably silane coupling agent such as KH-550 or KH-560. The antioxidant is selected from antioxidant 1010 or antioxidant 168 or a combination thereof, and preferably a combination of antioxidant 1010 and antioxidant 168, and the weight ratio of the combination is antioxidant 1010:antioxidant 168 = 1-2:1.

[0013] For the above components, further preferably, the amount of each component in the system is 4 parts of nylon toughening agent, 1 part of coupling agent, 1.5 parts of antioxidant, and 1 part of anti-glass fiber exposure agent TAF.

[0014] The introduction of the nylon toughening agent can affect the two-phase morphology in the PA66 and PA610 resin, form an ideal "island-in-sea structure", and thus improve the overall toughness, impact resistance and low-temperature crack resistance of the material. While ensuring the strength of the material, the impact strength and elongation at break are significantly improved, achieving a balance between rigidity and toughness.

[0015] The coupling agent can reduce the interfacial tension between the two phases, improve the interfacial wettability, enhance the interfacial bonding between the resin and the filler, inhibit the generation of interfacial defects, and improve the interfacial bonding strength.

[0016] The main function of the antioxidant is to prevent thermal oxidation of the nylon molecules during high-temperature processing and long-term use. By capturing free radicals and decomposing peroxides, the molecular chain integrity is maintained, thereby improving the thermal stability, anti-aging property and mechanical retention rate of the material.

[0017] The anti-glass fiber exposure agent TAF can improve the flow state of the material, reduce the shear force and flow resistance between the melt and the die during the forming process of the printing wire material, reduce the fiber peeling, adjust the rheological properties of the melt and the interfacial stress, and reduce the carbon fiber surface floating. It can improve the appearance of the wire material and ultimately improve the appearance of the 3D printed product.

[0018] The preparation method of the reinforced composite material is specifically a blending extrusion method. The extrusion method can be a screw extrusion process commonly used in the field of engineering plastic processing modification. The process conditions and equipment are the common conditions and equipment in the prior art. Preferably, a double-screw extrusion method can be used.

[0019] In a specific embodiment of the present application, the PA66 and PA610 materials are first dried, and then the components of the raw materials are directly mixed uniformly in a mixing device (such as a high-speed mixer), and then blended and melt-extruded in a double-screw extruder to obtain the composite material. The blending and extrusion conditions are as follows: the blending and extrusion temperature is 220-270°C, and the extruder speed is 20-35 rpm. Preferably, the blending and extrusion temperature is 240-260°C, and the extruder speed is 23-28 rpm.

[0020] The drying conditions are as follows: the drying temperature is 70-100°C, and the drying time is 4-8 h. Preferably, the drying temperature is 80-90°C, and the drying time is 5-6 h.

[0021] After obtaining the composite material, the present application further provides an application thereof in preparing a continuous carbon fiber-reinforced 3D printing filament. The preparation method comprises continuously melt-extruding the composite material through a double-screw extruder, introducing a continuous carbon fiber melt impregnation process at the end of the material extrusion, and obtaining the 3D printing filament through cooling, orientation and drawing.

[0022] In a specific embodiment of the present application, a step-by-step process can be used, in which the PA66 / PA610 composite material is first prepared, and then a continuous carbon fiber 3D printing filament is obtained by impregnating the continuous carbon fiber. Alternatively, a one-step continuous melt-extrusion and impregnation method can be used, in which the raw materials of the PA66 / PA610 composite material are directly melt-extruded in a double-screw extruder, and then directly introduced into a continuous carbon fiber impregnation process, cooled and drawn to obtain a continuous carbon fiber 3D printing filament.

[0023] The continuous carbon fiber used is selected from common carbon fibers such as 1K, 3K and 12K, preferably 1K or 3K small-tow carbon fiber. Specifically, it can be selected from one of Toray T300-1K, T300-3K, T700G-3K, Guangwei Composite TZ300-1K, TZ300-3K, Zhongfu Shenying SYT45-1K, SYT45S-3K, SYT49S-3K, Jiangsu Hengshen HF20-1K, HF20-3K, Jilin Carbon Valley T300-1K, and more preferably from SYT45-1K, SYT45S-3K and SYT49C-3K of Zhongfu Shenying.

[0024] Preferably, the raw materials for extrusion molding can be mixed by double screw extrusion, specifically, PA66, PA610, nylon toughening agent, coupling agent, antioxidant and anti-glass fiber exposure agent TAF are directly fed into the melt impregnation mold after melt extrusion by a double screw extruder, the broken twisted carbon fibers are pulled through the melt impregnation mold, a layer of resin composite material is coated on the surface of the carbon fibers, and the 3D printing wire is formed after the melt impregnation mold is shaped, cooled, drawn and wound. The above scheme is a one-step continuous melt extrusion impregnation method; the melt impregnation conditions are: melt impregnation temperature 230-260℃; preferably, the melt impregnation temperature is 240-255℃; the pulling speed of the orientation drawing is 0.5-4.2 rpm, preferably 1.5-3.6 rpm; the die diameter of the melt impregnation mold is 0.4-1.5 mm, preferably 0.6-0.8 mm.

[0025] In addition, the PA66, PA610, nylon toughening agent, coupling agent, antioxidant and anti-glass fiber exposure agent TAF can also be processed in the following step-by-step manner: the composite material is obtained after melt extrusion by a double screw extruder, and when 3D printing wire is needed, the above composite material is fed into the double screw extruder for melt extrusion again, and then the impregnation operation in the above section is repeated after extrusion into the melt impregnation mold. At this time, the secondary melt extrusion conditions of the composite material are: melt extrusion temperature 220-270℃, and the extruder speed is 20-35 rpm; preferably, the melt extrusion temperature is 240-260℃, and the extruder speed is 23-28 rpm, which is the same as the conditions for preparing the composite material.

[0026] Due to the different melt strength and processing performance of polymer materials, the orientation drawing of the printing wire is controlled by using appropriate pulling frequency (speed) and die diameter in the present application, and the excess attached composite material is removed by the die, further controlling the diameter of the wire and the fiber content in the wire, and obtaining continuous carbon fiber 3D printing wire meeting the printing requirements. At the same time, the melt impregnation mold can round the printing wire, make the printing wire more uniform, control the wire diameter, and facilitate 3D printing; at the same time, different carbon fibers and fiber contents can be selected according to the use, so as to meet the needs of different applications.

[0027] In the above method for preparing 3D printing wire, the wire after melt extrusion needs to be cooled, and the cooling treatment can be carried out by using a common cooling method, for example: the cooling treatment includes at least two stages of cooling with different temperatures, and the temperature decreases from the first stage to the last stage; preferably, in the cooling treatment, the first stage cooling adopts air cooling, and the last stage cooling adopts natural cooling; more preferably, in the cooling treatment, the first stage cooling path length is controlled to be 50-60 cm, and the last stage cooling is controlled to be 20-40 cm.

[0028] The inventors detected the tensile strength, tensile modulus and bending strength of the continuous carbon fiber reinforced PA66 / PA610 composite 3D printing filament obtained above, pure PA66 filament without adding carbon fiber and PA66 filament modified by short fibers in the prior art, and the results are shown in the following table. Table 1 Properties of continuous carbon fiber reinforced PA66 / PA610 composite 3D printing filament and other filaments It can be seen that the various indicators of the printing filament obtained by the application are greatly improved compared with the pure PA66 filament without adding carbon fiber and the PA66 filament modified by short fibers in the prior art, and are more suitable for the needs of 3D printing.

[0029] Compared with the prior art, the beneficial effects of the application are as follows: (1) By introducing PA610 resin into PA66 resin, the application reduces the density of amide groups in PA66 pure resin material and reduces the hydrophilicity of the material, thereby reducing the water absorption of the prepared 3D printing filament and ensuring the process performance and dimensional stability of the printed product.

[0030] (2) The 3D printing filament provided by the application is made of continuous carbon fiber, which is beneficial to the improvement of the strength and rigidity of the material and the product, and the tensile strength of the material single filament is increased by more than 1-2 times compared with short fiber reinforced filament, the tensile strength of the printed product is significantly improved, and the degree of deformation is reduced.

[0031] (3) The preparation method provided by the application has better material mixing effect than single screw forming, and the overall process flow is simple after integrating a double screw extruder for melt impregnation, the impregnation effect is good, it is suitable for industrial production and has wide application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The structure of the continuous carbon fiber reinforced PA66 / PA610 composite 3D printing filament obtained by the application is shown in the figure, the central dark part is carbon fiber, and the outer light part is PA66 / PA610 composite material; Figure 2 The figure is a physical photo of the continuous carbon fiber reinforced PA66 / PA610 composite 3D printing filament obtained by the application. DETAILED DESCRIPTION

[0033] The present application will be further described below in conjunction with specific embodiments, which can enable those skilled in the art to more fully understand the present application, but in no way limit the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0034] In the following examples: Tensile strength and tensile modulus were tested according to the standard of ASTM D 3039; and the bending strength was tested according to GB / T9341-2008.

[0035] Example 1: A reinforced composite material and its application in preparing continuous carbon fiber reinforced 3D printing filaments, the specific scheme is as follows: (1) The mixture of 65 parts of PA66 resin (viscosity of 2.4), 28 parts of PA610 (viscosity of 2.1), 4 parts of POE-g-MAH, and 1 part of silane coupling agent mixture KH-550, 1 part of antioxidant (antioxidant 1010: antioxidant 168 weight ratio of 1:1), and 1 part of TAF was melt extruded and then pelletized to obtain a composite material. The temperature of the first section of the extruder barrel was 245°C, the temperature of the second section was 255°C, the temperature of the third section was 255°C, and the temperature of the fourth section was 260°C. The rotation speed of the extruder was 25 rpm.

[0036] (2) The continuous carbon fiber bundle (Zhongfushenying SYT45-1K) was subjected to twist breaking, filament separation, and temperature pretreatment by airflow and heating device, and the filament bundle was broken and separated; the upper and lower surfaces of the continuous carbon fiber filament bundle were heated by the heating device, and the heating temperature was 140°C; the above treatment of the carbon fiber can significantly improve the cleanliness of the fiber surface, remove part of the incompatible sizing agent, thereby improving the melt impregnation effect of PA66 / PA610 and carbon fiber, improving the interfacial bonding strength, and reducing the defects of the filament.

[0037] The carbon fiber bundle after twist breaking of the filament was drawn into a melt impregnation mold, and the composite material and Zhongfushenying SYT45-1K carbon fiber were melt impregnated by the melt impregnation mold; specifically, the obtained composite material was again fed into a double screw extruder, and the outlet of the double screw extruder was directly connected to the melt impregnation mold, so that the melt of the second melt PA66 / PA610 composite material could perform the impregnation process on the carbon fiber bundle; wherein the temperature of the first section of the extruder barrel was 245°C, the temperature of the second section was 255°C, the temperature of the third section was 255°C, and the temperature of the fourth section was 260°C. The rotation speed of the extruder was 25 rpm; the temperature of the impregnation mold was 260°C, and the traction rotation speed was 3.6 rpm. (3) The fiber after impregnation was formed through a circular shaping die with a diameter of 0.6 mm, and was cooled and shaped by an air cooling device to obtain a filament for 3D printing, and the filament diameter was 0.6 mm. The detection showed that the carbon fiber content of the filament was 40%, and the filament was wound into a filament product by a winding machine (the appearance of the filament product is shown in Figure 1 and 2 ).

[0038] The performance indicators of the carbon fiber reinforced PA66 / PA610 composite 3D printing wire produced in this embodiment are as follows: Table 2 Performance of continuous carbon fiber reinforced PA66 / PA610 composite 3D printing wire .

[0039] Example 2, a reinforced composite material and its application in preparing continuous carbon fiber reinforced 3D printing wire, the specific scheme is as follows: (1) The continuous carbon fiber bundle (SYT45-1K) is subjected to filament separation and temperature rising pretreatment by airflow and heating device, and the filament separation is completed. The upper and lower surfaces of the continuous carbon fiber bundle are heated by the heating device, and the heating temperature is 160°C. The carbon fiber bundle after filament separation enters the melt impregnation mold.

[0040] (2) The mixture of 70 parts of PA66 resin (viscosity 2.4), 23 parts of PA610 (viscosity 2.1), 4 parts of POE-g-MAH, 1 part of antioxidant (antioxidant 1010: antioxidant 168 weight ratio is 1:1), 1 part of TAF and 1 part of silane coupling agent KH-550 is melt plasticized by a double screw extruder, and then continuously fed to the melt impregnation mold; The temperature of the double screw extruder is 245°C in the first zone, 245°C in the second zone, 250°C in the third zone, and 255°C in the fourth zone, and the rotation speed is 28 rpm. The temperature of the impregnation mold is 255°C, and the traction rotation speed is 2.0 rpm.

[0041] (3) The impregnated fiber is formed through a circular shaping die with a diameter of 0.8 mm, and is cooled and shaped by an air cooling device to obtain a 3D printing wire with a diameter of 0.8 mm and a fiber content of 40%, which is wound into a wire product by a winding machine.

[0042] The performance indicators of the carbon fiber reinforced PA66 / PA610 composite 3D printing wire produced in this embodiment are as follows: Table 3 Performance of continuous carbon fiber reinforced PA66 / PA610 composite 3D printing wire .

[0043] Example 3, a reinforced composite material and its application in preparing continuous carbon fiber reinforced 3D printing wire, the specific scheme is as follows: (1) The continuous carbon fiber bundle (SYT45S-3K) is subjected to filament separation and temperature rising pretreatment by airflow and heating device, and the filament separation is completed. The upper and lower surfaces of the continuous carbon fiber bundle are heated by the heating device, and the heating temperature is 180°C. The carbon fiber bundle after filament separation enters the melt impregnation mold.

[0044] (2) Through the double screw extruder, 75 parts of PA66 resin (viscosity 2.4), 18 parts of PA610 (viscosity 2.1), 4 parts of POE-g-MAH toughening agent, 1 part of antioxidant (antioxidant 1010: antioxidant 168 weight ratio 2:1), 1 part of TAF and 1 part of silane coupling agent KH-550 mixture are melt plasticized to supply the filament melt impregnation mold, wherein the temperature of the first zone of the double screw extruder is 255℃, the temperature of the second zone is 265℃, the temperature of the third zone is 265℃, the temperature of the fourth zone is 265℃, the rotating speed is 23 rpm, the temperature of the impregnation mold is 265℃, and the pulling rotating speed is 3.0 rpm.

[0045] (3) The impregnated fiber is formed through a circular shaping die with a diameter of 1.0 mm, and is cooled and shaped through an air cooling device to become a filament material for 3D printing, with a filament material diameter of 1.0 mm and a fiber content of 40%, and is wound into a filament material product by a winding machine.

[0046] After detection, the performance indicators of the carbon fiber reinforced PA66 / PA610 composite 3D printing filament produced in this embodiment are as follows: Table 4 Performance of continuous carbon fiber reinforced PA66 / PA610 composite 3D printing filament .

[0047] The purpose of this comparative example is to investigate the influence of PA610 on the performance of the composite 3D printing filament.

[0048] The continuous carbon fiber reinforced PA66 composite 3D printing filament is formed according to the following steps: (1) The continuous carbon fiber bundle (SYT45-1K) is subjected to filament separation and temperature pretreatment by airflow and heating device, and the upper and lower surfaces of the continuous carbon fiber bundle are subjected to heating treatment by the heating device, and the heating temperature is 140℃; the carbon fiber bundle after filament separation enters the melt impregnation mold.

[0049] (2) Through the double screw extruder, 94 parts of PA66 resin (viscosity 2.4), 4 parts of POE-g-MAH, 0.5 parts of antioxidant (antioxidant 1010: antioxidant 168 weight ratio 1:1), 0.5 parts of TAF and 1 part of silane coupling agent KH-550 mixture are melt plasticized to supply the filament melt impregnation mold, wherein the temperature of the first zone of the double screw extruder is 245℃, the temperature of the second zone is 245℃, the temperature of the third zone is 250℃, the temperature of the fourth zone is 255℃, the temperature of the impregnation mold is 255℃, and the pulling rotating speed is 3.6 rpm (3) The impregnated fibers are formed through a circular shaping die with a diameter of 0.8 mm, and are cooled and shaped by an air cooling device to obtain the filament material for 3D printing, with a filament material diameter of 0.8 mm and a fiber content of 40%, and the filament material is wound by a winding machine to obtain a filament material product.

[0050] The performance indicators of the carbon fiber reinforced PA66 composite 3D printing filament material produced in the comparative example are as follows: Table 5 Performance of continuous carbon fiber reinforced PA66 composite 3D printing filament material It can be seen by comparison that the performance of the carbon fiber reinforced PA66 composite 3D printing filament material produced using pure PA66 is obviously lower than that of the PA66 / PA610 composite filament material. Compared with Example 1, the water absorption increases significantly, the tensile strength decreases from 527.4 MPa to 425.6 MPa, a decrease of 19.3%; the tensile modulus decreases from 27.6 Gpa to 18.2 Gpa, a decrease of 34.1%; the bending strength decreases from 263.4 MPa to 186.5 MPa, a decrease of 29.2%. The reason is that the processing window of PA66 is short and the viscosity is large, and the continuous carbon fiber is broken during the impregnation process, resulting in low overall performance. Therefore, it is necessary to improve the processability by blending PA66 / PA610 and introduce continuous carbon fiber reinforcement to prepare 3D printing filament material.

[0051] Comparative Example 2 The purpose of this comparative example is to investigate the effect of continuous fibers on the performance of PA66 / PA610 composite 3D printing filament material (mainly compared with Example 3). The PA66 / PA610 composite 3D printing filament material is formed according to the following steps: 75 parts of PA66 resin (viscosity 2.4), 18 parts of PA610 (viscosity 2.1), 4 parts of POE-g-MAH toughening agent, 1 part of antioxidant (antioxidant 1010: antioxidant 168 weight ratio 2:1), and 1 part of TAF mixed with 1 part of silane coupling agent KH-550 are melt plasticized, and then directly formed through a circular shaping die with a diameter of 0.8 mm, and cooled and shaped by an air cooling device to obtain the filament material for 3D printing, with a filament material diameter of 0.8 mm, and wound by a winding machine to obtain a filament material product.

[0052] The temperature of the double screw extruder is 255°C in the first zone, 265°C in the second zone, 265°C in the third zone, and 265°C in the fourth zone, with a rotation speed of 23 rpm.

[0053] The performance indicators of the PA66 / PA610 composite 3D printing filament material produced are as follows: Table 6 Performance of PA66 / PA610 composite 3D printing filament material By comparison, compared with the continuous carbon fiber reinforced PA66 / PA610 composite wire, the performance of the PA66 / PA610 composite 3D printing wire without carbon fiber reinforcement is significantly reduced. Compared with Example 3, the tensile strength is reduced from 724.5 MPa to 83.6 MPa, a decrease of 88.5%; the tensile modulus is reduced from 42.2 Gpa to 2.9 Gpa, a decrease of 93.1%; the bending strength is reduced from 415.3 MPa to 123.8 MPa, a decrease of 70.2%. Therefore, it is necessary to use continuous carbon fiber to reinforce the PA66 / PA610 composite 3D printing wire.

[0054] The above-described embodiments are only to describe the preferred embodiments of the present application, and not to limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by ordinary engineering technicians in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A reinforced composite material, characterized in that, The raw material composition by weight is as follows: 60-80 parts PA66, 15-35 parts PA610, 3.5-4.5 parts nylon toughening agent, 0.5-1.5 parts coupling agent, 1-3 parts antioxidant, and 1-2 parts anti-glass fiber exposure agent TAF.

2. The reinforced composite material according to claim 1, characterized in that, The raw material composition by weight is as follows: 65-75 parts PA66, 20-30 parts PA610, 3.5-4.5 parts nylon toughening agent, 0.5-1.5 parts coupling agent, 1-2 parts antioxidant, and 1-2 parts anti-glass fiber exposure agent TAF.

3. The reinforced composite material according to claim 1 or 2, characterized in that, The viscosity of PA66 is ≤2.50; the viscosity of PA610 is ≤2.

20.

4. The reinforced composite material according to claim 1 or 2, characterized in that, The nylon toughening agent is selected from maleic anhydride-grafted polyolefin elastomer or maleic anhydride-grafted EPDM rubber; the coupling agent is selected from silane coupling agent or titanate coupling agent; the antioxidant is selected from antioxidant 1010 or antioxidant 168 or their compound.

5. The reinforced composite material according to claim 4, characterized in that, The nylon toughening agent is selected from maleic anhydride-grafted polyolefin elastomer; the coupling agent is selected from KH-550 or KH-560; the antioxidant is selected from antioxidant 1010 and antioxidant 168 in a compound weight ratio of antioxidant 1010: antioxidant 168 = 1 to 2:

1.

6. The method for preparing the reinforced composite material according to claim 1, characterized in that, The specific steps are as follows: First, PA66 and PA610 materials are dried. Then, the raw materials of each component are mixed evenly in a mixing device and then melt-extruded through a twin-screw extruder to obtain the composite material. The blending extrusion conditions are: blending extrusion temperature 220-270℃, extruder speed 20-35 rpm; the drying conditions are: drying temperature 70-100℃, drying time 4-8h.

7. The method for preparing the reinforced composite material according to claim 6, characterized in that, The temperature of the blend extrusion is 240–260℃, the extruder speed is 23–28 rpm, the drying temperature is 80–90℃, and the drying time is 5–6 h.

8. The application of the reinforced composite material according to claim 1 in the preparation of continuous carbon fiber reinforced 3D printing filaments, characterized in that: The composite material is continuously melt-extruded using a twin-screw extruder, and a continuous carbon fiber melt impregnation process is introduced at the end of the material extrusion. After cooling and orientation stretching, the 3D printing filament is obtained. The continuous carbon fiber used is selected from 1K, 3K, and 12K carbon fibers.

9. The application of the reinforced composite material according to claim 8 in the preparation of continuous carbon fiber reinforced 3D printing filaments, characterized in that: The melt impregnation conditions are as follows: melt impregnation temperature 230-260℃, traction speed of orientation stretching 0.5-4.2 rpm, and die diameter of melt impregnation mold 0.4-1.5 mm.

10. The application of the reinforced composite material according to claim 9 in the preparation of continuous carbon fiber reinforced 3D printing filaments, characterized in that: The melt impregnation temperature is 240–255℃; the traction speed of the orientation stretching is 1.5–3.6 rpm; and the diameter of the melt impregnation die is 0.6–0.8 mm.

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