Continuous fiber reinforced polyamide composite material for 3D printing as well as preparation and application of continuous fiber reinforced polyamide composite material

Abstract

The invention belongs to the field of composite materials, and discloses a continuous fiber reinforced polyamide composite material for 3D printing and a preparation method and application thereof. The polyamide composite material comprises a component A and a component B, wherein the component A comprises the following components in percentage by weight: 125%-79.9% of polyamide PA; 5 to 10% of polyamide PA1012; 15%-30% of a polyamide copolymer cPA; 0%-1% of an antioxidant; the component B is carbon fiber or glass fiber, and the use amount of the component B is 10-30% of the weight of the component A. And the component A can also comprise sodium tetraborate decahydrate. The continuous fiber reinforced polyamide composite material for 3D printing has higher interlayer strength and bending strength, so that the continuous carbon fiber reinforced material for 3D printing can be suitable for more applications. Meanwhile, the preparation method disclosed by the invention is simple and feasible, and is suitable for large-scale production.

Description

Technical Field

[0001] The present invention belongs to the field of composite materials, and in particular relates to a continuous fiber reinforced polyamide composite material for 3D printing, and a preparation method and application thereof. Background Art

[0002] 3D printing with continuous fiber reinforced thermoplastic resin is a current research hotspot, and its main purpose is to significantly improve the strength of 3D printing materials. The main method used is to directly introduce the continuous fiber bundle into the nozzle of the printer, and the continuous fiber bundle and the 3D printing filament are printed through the nozzle of the printer at the same time. A major problem that plagues 3D printing, including continuous fiber reinforced 3D printing, is that the interlayer strength of 3D printed products is significantly lower than the strength of the material itself. Studies have shown that optimizing material properties can significantly improve interlayer strength. Nylon 12 is a resin material that can better balance interlayer strength and other properties that has been screened out in the market, but the interlayer strength is still significantly lower than the strength of the material itself. Especially in continuous fiber reinforced 3D printing, due to the obvious orientation of the continuous fiber, the performance improvement of interlayer strength will be further limited. Moreover, due to its low melting point and strength, the strength of nylon 12 will also be subject to certain limitations in the orientation perpendicular to the interlayer. Summary of the invention

[0003] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the object of the present invention is to provide a continuous fiber reinforced polyamide composite material for 3D printing with higher interlaminar strength, achieve better mechanical properties, and expand the potential application range.

[0004] Another object of the present invention is to provide a method for preparing the above-mentioned continuous fiber reinforced polyamide composite material for 3D printing with higher interlaminar strength.

[0005] Another object of the present invention is to provide an application of the above-mentioned continuous fiber reinforced polyamide composite material for 3D printing with higher interlaminar strength. The purpose of the present invention is achieved through the following solutions: A continuous fiber reinforced polyamide composite material for 3D printing, comprising a component A and a component B, wherein the component A comprises the following components in percentage by weight: Polyamide PA12 59%-79.9%; Polyamide PA1012 5-10%; Polyamide copolymer cPA 15%-30%; Antioxidant 0%-1%; Component B is continuous fiber, which is carbon fiber or glass fiber. The amount of component B is 10-30% of the weight of component A.

[0006] Preferably, the polyamide composite material for 3D printing continuous fiber reinforcement comprises component A and component B, wherein component A comprises the following components in the following weight percentages: Polyamide PA12 64.6-74.9%; Polyamide PA1012 5-10%; Polyamide copolymer cPA 20-25%; Antioxidant 0-0.5%; Component B is continuous fiber, which is carbon fiber or glass fiber. The amount of component B is 10-30% of the weight of component A.

[0007] The polyamide copolymer cPA is copolymerized by monomer A, monomer B and monomer C, wherein the mass of monomer A, monomer B and monomer C accounts for 60%-80%, 10%-20% and 10-20% of the total mass of the three monomers (monomer A, monomer B and monomer C) respectively. The monomer A is a blend of decanediamine and an aliphatic dibasic acid, and the molar ratio of decanediamine to the aliphatic dibasic acid adipic acid is (0.98-1.02):1; the monomer B is a mixture of polytetrahydrofuran diamine with a molecular weight of 900-1500 and an aliphatic dibasic acid, and the molar ratio of polytetrahydrofuran diamine to the aliphatic dibasic acid is (0.98-1.02):1; the monomer C is a mixture of an alicyclic monomer and an aliphatic dibasic acid, and the alicyclic monomer is one of MACM and PACM, and the molar ratio of the alicyclic monomer to the aliphatic dibasic acid is (0.98-1.02):1; the aliphatic dibasic acids in the monomers A, B and C are all relatively independently at least one of succinic acid, adipic acid and azelaic acid.

[0008] Preferably, in the polyamide copolymer cPA, monomer A is a mixture of decanediamine and adipic acid, monomer B is a mixture of polytetrahydrofuran diamine and adipic acid, monomer C is a mixture of MACM and adipic acid, and the mass of monomer A, monomer B and monomer C accounts for 70%, 10% and 20% of the total mass of the three monomers (monomer A, monomer B and monomer C), respectively.

[0009] The polyamide PA copolymer is prepared by the following method: Step 1: Add monomers A, B, C and catalyst into a polymerization reactor; Step 2: Nitrogen purging, the pressure is maintained at 0.3-1.0MPa; Step 3: Heat the solution to 100-140°C and stir for 1-3h; Step 4: Continue to heat up to 220-260℃ and maintain pressure for 1-3h; Step 5: The pressure is reduced to 0 MPa, and the polyamide copolymer cPA is obtained after vacuuming for 5-240 minutes according to the required viscosity.

[0010] The catalyst in step 1 is one or a mixture of hypophosphorous acid, phosphoric acid, and hypophosphite. The amount of the catalyst is such that the weight of the catalyst accounts for 0.05-0.2% of the total weight of the three monomers. Preferably, the viscosity index (viscosity number VN) of the polyamide copolymer cPA is 140-220, preferably 190-220.

[0011] Preferably, the viscosity index of the polyamide PA1012 is 150-220, preferably 160-180.

[0012] Preferably, the viscosity index of the polyamide PA12 is 100-250.

[0013] The antioxidant is at least one of hindered phenol antioxidants, hindered amine antioxidants, and cuprous salt antioxidants, and is preferably antioxidant 1098.

[0014] Preferably, the component A of the polyamide composite material may also contain 0.1%-0.5% by weight of sodium tetraborate decahydrate.

[0015] A method for preparing a continuous carbon fiber reinforced polyamide composite material for 3D printing, comprising the following steps: melt-blending the raw materials of component A to obtain an impregnation solution; impregnating the continuous fibers of component B in the impregnation solution, and then shaping and cooling to obtain a continuous fiber prepreg for 3D printing; and then printing the continuous fiber prepreg for 3D printing with a 3D printer to obtain a continuous fiber reinforced polyamide composite material for 3D printing.

[0016] Preferably, the method for preparing the continuous carbon fiber reinforced polyamide composite material for 3D printing specifically comprises the following steps: (1) After the continuous fiber bundle is unwound by the unwinding roller, it is first pre-dispersed by the pre-tensioning roller, and then the upper and lower surfaces of the continuous fiber bundle are preheated by the infrared radiation device; (2) The preheated continuous fibers are disturbed along the direction perpendicular to the fiber dragging direction and the direction parallel to the fiber dragging direction, so that the preheated fiber bundles become loose, and then the yarn is spread; (3) The raw materials of component A are melted and mixed to obtain a modified plastic melt, which enters the wire impregnation mold, and the expanded fiber bundles enter the wire impregnation mold at the same time to complete the impregnation process of the plastic melt on the fiber bundles. The impregnated fibers are formed by a shaping die and cooled to shape. The shaped wire is a continuous fiber prepreg that can be used for 3D printing; (4) The obtained continuous fiber prepreg is cooled and then printed by a 3D printer to obtain a 3D printed product of a continuous carbon fiber reinforced polyamide composite material.

[0017] The device used in the above-mentioned preparation method for 3D printing continuous carbon fiber reinforced polyamide composite materials includes a unwinding roller device, a pre-tensioning device, an infrared radiation device, a swinging device, a pneumatic auxiliary spreading device, a wire impregnation device, a twin-screw extruder, a cooling device and a 3D printing device, including an unwinding roller, a twin-screw extruder, a pre-tensioning roller, an infrared radiation device, a gas-assisted swinging device, a wire impregnation mold, a cooling device and a 3D printer.

[0018] The above-mentioned continuous fiber reinforced polyamide composite material for 3D printing is used in shoe materials and plates.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects: The continuous fiber reinforced polyamide composite material for 3D printing of the present invention has higher interlaminar strength and flexural strength, so that the 3D printing continuous carbon fiber reinforced material can be applied to more applications. At the same time, the preparation method of the present invention is simple and easy to implement, and is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the production system of continuous fiber impregnation reinforced resin 3D printing of the present invention.

[0021] Figure 2 It is a three-dimensional structural schematic diagram of the twin-screw extruder and the wire material impregnation device of the present invention.

[0022] Figure 3 It is a partial cross-sectional view of the twin-screw extruder and the wire material impregnation device of the present invention.

[0023] Figure 4 It is a structural schematic diagram of the swing device of the present invention.

[0024] Figure 5 It is a top view of the pneumatic assisted expansion device of the present invention.

[0025] Among them, 1-unwinding roller device, 2-pre-tensioning device, 201-tensioning roller, 3-infrared radiation device, 4-swinging device, 401-cam, 402-driving shaft, 403-coupling, 404-stepping motor, 5-pneumatic auxiliary expansion device, 501-rotating roller, 6-wire infiltration device, 6a-infiltration chamber, 6b-plastic melt conveying device, 601-wavy flow channel, 602-heating rod, 603-forming die, 604-inner traction roller, 7-screw extrusion device, 8-cooling device, 9-3D printing device, 901-divergent nozzle, 902-traction roller. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the examples and drawings, but the embodiments of the present invention are not limited thereto. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0027] The technical solution of the present application is described in detail below using an embodiment. The preparation method of the polyamide copolymer cPA in the embodiment is as follows: monomers A, B, C and a catalyst hypophosphorous acid are added to a polymerization kettle; nitrogen is purged and the pressure is maintained at 0.5 MPa; the solution is heated to 120° C. and stirred at a constant temperature for 2 hours; the temperature is further raised to 240° C. and the pressure is maintained for 2 hours; the exhaust pressure is reduced to 0 MPa, and the polyamide copolymer cPA is obtained after vacuuming for 5-240 minutes according to the required viscosity. According to different vacuuming times, polyamide copolymers cPA1 (VN=140), polyamide copolymers cPA2 (VN=180), and polyamide copolymers cPA3 (VN=210) are obtained. In the polyamide copolymers cPA1, cPA2, and cPA3 used in the embodiment, monomer A is a mixture of decanediamine and adipic acid, monomer B is a mixture of polytetrahydrofuran diamine and adipic acid, and monomer C is a mixture of MACM and adipic acid. The mass of monomer A, monomer B, and monomer C accounts for 70%, 10%, and 20% of the total mass of the three monomers (monomer A, monomer B, and monomer C), respectively. The molar ratio of decanediamine to aliphatic dibasic acid in monomer A is 1.02:1; the molecular weight of polytetrahydrofuran diamine in monomer B is 1000, and the molar ratio of polytetrahydrofuran diamine to aliphatic dibasic acid is 1:1; the molar ratio of MACM to aliphatic dibasic acid in monomer C is 1:1. The amount of the catalyst hypophosphorous acid added is 0.1% of the total weight of the three monomers. For details, see the patent application "CN202311374296.9 A transparent nylon elastomer and its preparation method".

[0028] The remaining raw materials in the embodiment can be obtained from the market, specifically as follows: polyamide PA12 is Grilamid L25 (VN=180) of EMS, polyamide PA1012 (VN=160) is Vestamid Terra DD16 of Evonik, polyamide PA1012 (VN=180) is Vestamid Terra DD18 of Evonik, polyamide PA1012 (VN=220) is Vestamid Terra DD22 of Evonik, antioxidant 1098 is Tianjin Lianlong 1098, sodium tetraborate decahydrate is AR reagent of Sinopharm Group, and carbon fiber is Zhongfu Shenying SYT45.

[0029] The bending strength in the present invention refers to ISO527 standard, and the interlaminar shear sample refers to JC / T773-2010 standard. Five samples are tested for each group of samples, and the average value is taken.

[0030] The present invention uses a continuous fiber impregnation reinforcement 3D printing integrated device to process composite materials. Figure 1 As shown, the integrated device includes a reel device 1, a pre-tensioning device 2, an infrared radiation device 3, a swing device 4, a pneumatic auxiliary spreading device 5, a wire infiltration device 6, a twin-screw extruder 7, a cooling device 8 and a 3D printing device, and the overall layout is in a strip shape.

[0031] like Figure 1-Figure 5 As shown, the pre-tensioning device 2 has a plurality of staggered tensioning rollers 201 for pre-dispersing the continuous fiber bundle. In this embodiment, the number of tensioning rollers 201 is three, and the three tensioning rollers 201 are staggered so that the conveying path of the continuous fiber bundle is wavy. The infrared radiation device 3 is used to preheat the pre-dispersed continuous fiber bundle, wherein the infrared radiation device 3 includes a first infrared radiation module and a second infrared radiation module arranged up and down, and an infrared radiation channel for conveying the continuous fiber bundle is formed therebetween. The swing device 4 is located downstream of the infrared radiation device 3, and is used to disturb the preheated continuous fiber bundle in a direction perpendicular to the fiber dragging direction and in a direction parallel to the fiber dragging direction. The pneumatic auxiliary spreading device 5 is located downstream of the swing device 4, and has a plurality of rotating rollers 501 for conveying the continuous fiber bundle, and has an airflow inlet at the top, and the continuous fiber bundle is split and spread by high-pressure gas blowing. The swing device 4 includes a cam 401, a drive shaft 402, a coupling 403 and a stepper motor 404 arranged in series. The cam 401 is connected to the drive shaft 402 by a key. The coupling 403 and the drive shaft 402 are driven by the stepper motor 404 to drive the cam 401 to rotate, so that the fiber bundle is disturbed along the direction perpendicular to the fiber dragging direction and the direction parallel to the fiber dragging direction, thereby improving the impregnation effect of the resin matrix on the fiber bundle. While tensioning the fiber bundle, it can also ensure that the preheated fiber bundle becomes loose, which is convenient for subsequent yarn spreading. The swing frequency of the cam 401 of the swing device 4 is 10-20r / min, and the eccentric amplitude is 10-15mm; the multiple rotating rollers 501 of the pneumatic auxiliary spreading device 5 are driven by a motor, the air flow speed is 2-8m / min, the air flow direction is perpendicular to the conveying direction of the fiber bundle, and passes through between the fiber filaments, which can effectively avoid fiber damage, and the fiber bundle is guided and limited by the multiple rotating rollers 501. There are three rotating rollers 501, including two guide rollers and one limiting roller. The position of the limiting roller can be adjusted up and down. After the yarn is spread by the pneumatic auxiliary spreading device 5, the width of a single bundle of fibers is 15-25mm and the thickness is 0.03-0.06mm.

[0032] like Figure 1 and Figure 3 As shown, X is the length direction of the wire infiltration device 6, and Y is the width direction of the wire infiltration device 6. The wire infiltration device 6 includes an infiltration chamber 6a and a plastic melt conveying device 6b arranged up and down. A fluid channel is provided in the plastic melt conveying device 6b. The twin-screw extruder 7 is connected to the wire infiltration device 6 in a parallel manner. The plastic melt conveyed by the twin-screw extruder 7 enters the fluid channel of the plastic melt conveying device 6b along the length direction (X) of the wire infiltration device 6. The fluid channel has a slope and a corner design, and then enters the wire infiltration device 6 along the length direction of the wire infiltration device 6 through the fluid channel. Among them, the cross-section of the plastic melt conveying device 6b along the length direction (X) of the wire infiltration device 6 is square, the side length of the square is L, the fluid channel has three corners (R1, R2, R3), the curvature radius of R1 is 0.1L-0.3L, the curvature radius of R2 is 0.1L-0.3L, and the curvature radius of R3 is 0.8L-1.2L.

[0033] The twin-screw extruder 7 includes a barrel, one end of the barrel has a feed port, the other end of the barrel has a discharge port, the side of the barrel near the discharge port has a vacuum port, the barrel includes a solid conveying section, a melting section, a melt conveying section, and a vacuum exhaust section, the vacuum exhaust section discharges the gas remaining in the material, the conveying thread element of the vacuum exhaust section no longer uses a conveying element with a smaller thread pitch, but uses a conveying element with a larger thread pitch, the thread pitch of the vacuum exhaust section is 1.5D-2D, D is the inner diameter of the barrel; the thread pitch of the solid conveying section is 1 D-2D, the thread pitch of the melting section is 0.5D-1D, and the thread pitch of the melt conveying section is 1D; the screw diameter of the twin-screw extruder 7 is 18mm-90mm, the aspect ratio is 40-60, the screw speed is 0-500rpm / min, the resin raw material enters from the feed port, and through the turning, mixing and conveying of the twin screws, the plastic melt is discharged from the discharge port and conveyed to the fluid channel of the plastic melt conveying device 6b, wherein the vacuum port is used to exhaust and extract the gas in the barrel to prevent the gas from entering the fluid channel of the plastic melt conveying device 6b. The wire impregnation device 6 has a wavy flow channel 601, the covering angle of the wavy flow channel 601 is 300°-450°, the gap of the wavy flow channel 601 is 8~10mm, and multiple heating rods 602 are arranged at the top and bottom of the wavy flow channel 601. A shaping die 603 is provided at the outlet end of the wavy flow channel 601. The diameter D of the shaping die 603 is 0.7-1.2mm and the length is 15~20D. An inner traction roller 604 is arranged in the shaping die 603. The inner traction roller 604 is a pair of metal rollers rotating in opposite directions and driven by a servo motor. It is used to pull the fiber bundle and realize the impregnation of the fiber bundle with the molten resin through the extrusion action. The pulling speed of the inner traction roller 604 on the fiber bundle is the same as the wire feeding speed of the 3D printing device 9.

[0034] like Figure 1 As shown, a 3D printing device 9 is located downstream of the wire impregnation device 6, and is used to heat and spray the impregnated fiber to obtain a 3D printed product of a continuous fiber reinforced thermoplastic composite material. The 3D printing device 9 includes a divergent nozzle, the divergence angle α of the divergent nozzle 901 is 30-60°, the length of the divergent section is 1-1.5 times the nozzle flow channel diameter, the outlet of the divergent nozzle 901 is rounded, and the edge width d of the divergent nozzle 901 is 2-4mm. It can ensure that the nozzle edge has a larger contact area with the surface of the product during the printing process, and the surface of the printed composite product is smooth and flat. Among them, the 3D printing device 9 also has a traction roller 902, which is used to guide the continuous fiber cooled by the cooling device 8 into the 3D printing device. The printing temperature is 250-320℃, and the printing speed is 50mm / min-2000mm / min.

[0035] like Figure 1 As shown, a cooling device 8 is further arranged between the wire impregnation device 6 and the 3D printing device 9, and the cooling device 8 is used to cool and shape the impregnated fibers; a reel device 1 for winding a continuous fiber bundle is also arranged upstream of the pre-tensioning device 2.

[0036] The continuous fibers are glass fibers or carbon fibers.

[0037] The 3D printing method using the continuous fiber reinforced thermoplastic resin melt impregnation 3D printing device of the present invention has the following process: (1) After being unwound by the unwinding roller 1, the continuous fiber bundle is firstly pre-dispersed by the pre-tensioning roller 2, and then the upper and lower surfaces of the continuous fiber bundle are preheated by the infrared radiation device 3, and the preheating temperature is 100-200°C.

[0038] (2) The preheated continuous fiber bundle is passed through the swing device 4, wherein the swing device 4 disturbs the continuous fibers along the direction perpendicular to and parallel to the fiber dragging direction through the eccentric rotation of the cam 401. The pneumatic auxiliary spreading device 5 provides airflow to the continuous fiber bundle, and the airflow direction is perpendicular to the conveying direction of the fiber bundle. Under the action of the initial fibers, the airflow speed on both sides of the fibers is greater than the airflow blocked by the fibers in the middle, thereby making the pressure on both sides lower. Under the action of the air pressure, the fiber bundle begins to gradually expand to both sides, so that the fiber bundle is split. The final expanded width of the fiber bundle is 15-25 mm and the thickness is 0.03-0.06 mm.

[0039] (3) The twin-screw extruder 7 melts and mixes various raw materials according to actual needs to obtain a modified plastic melt. The plastic melt enters the wire impregnation device 6 from a parallel direction, and the unfolded fiber bundle is introduced into the wire impregnation device 6. Under the action of the wavy flow channel 601, the resin matrix impregnates the fiber bundle. The impregnated fibers are transported forward by the inner traction roller 604, formed by the circular shaping die 603, and then cooled and shaped by the cooling device 8. The shaped wire is a continuous fiber prepreg that can be used for 3D printing, with a diameter of 0.7-1.2 mm.

[0040] (4) After the obtained continuous fiber prepreg is cooled, it is transported to the nozzle 901 of the printer through the wire feeding mechanism of the 3D printer 9. Under the action of the heat source of the heating block, the thermoplastic resin in the prepreg is heated and melted, and is deposited on the printing platform at the same extrusion rate as the fiber bundle, and finally a 3D printed product of a continuous fiber reinforced thermoplastic composite material is obtained.

[0041] In the following embodiments, the parameters of the resin-modified continuous fiber impregnation reinforced 3D printing integrated device are set as follows: the wrapping angle of the wavy flow channel in the wire impregnation device 6 is 350°, the flow channel gap is 10mm, the traction speed of the inner traction roller 604 is 5m / min, the diameter D of the shaping die 603 is 1mm, and the length is 15 times the diameter D. The cam 401 in the swing device 4 has a swing frequency of 12r / min and an eccentric amplitude of 10mm. The airflow velocity of the pneumatic auxiliary spreading device 5 is 5m / min, the width of a single fiber bundle after the yarn is spread by the pneumatic auxiliary swing device 5 is 20mm, and the thickness is 0.05mm, the preheating temperature of the infrared radiation device 3 is 180℃, the diameter of the shaping die 603 is 1mm, and the diameter of the obtained continuous fiber prepreg is 1mm. The divergence angle α of the nozzle of the 3D printer 9 is 45°, the divergence section length is 1.2 times the nozzle flow channel diameter, the nozzle edge width d is 3mm, the printing temperature is 285℃, and the printing speed is 150mm / min. The screw diameter of the twin-screw extruder 7 is 18mm, the aspect ratio is 48, the screw speed is 200rpm / min, the processing temperature is 250-270C, the solid conveying section uses 3 screw elements with a thread pitch of 1D and 3 screw elements with a thread pitch of 2D, the melting section uses 1 screw element with a thread pitch of 0.5D and 4 screw elements with a thread pitch of 1D, and the melt conveying section uses 4 screw elements with a thread pitch of 1D; the vacuum exhaust section after the vacuum port of the twin screw uses 2 conveying screw elements with 2D. In the fluid channel of the plastic melt conveying device 6b, R1=0.1L, R2=0.1L, and R3=1L.

[0042] Comparative Examples 1-5 and Examples 1-8 The weight proportions of the raw materials of the continuous fiber reinforced polyamide composite materials for 3D printing obtained in Comparative Examples 1-5 and Examples 1-8 and the performance data of the obtained 3D printed polyamide composite materials are shown in Table 1 below.

[0043] Table 1 Weight percentage and performance data of each raw material of the continuous fiber reinforced polyamide composite material for 3D printing obtained in Comparative Examples 1-5 and Examples 1-8 From the comparison of Comparative Example 1 in Table 1 and Examples 1-8, it can be seen that when PA1012 and polyamide copolymer cPA are added to PA12, the interlaminar strength of the material can be greatly improved, and at the same time, the flexural strength of the material is also improved to a certain extent. From the comparison of Comparative Examples 4-5 and Examples 1-3, it can be seen that when PA1012 and polyamide copolymer cPA are added to PA12 in a suitable proportion, the improvement effect on the interlaminar strength and flexural strength of the material is also better than that of adding the same amount of PA1012 or cPA alone, which shows that there is a synergistic effect between PA1012 and cPA in the polyamide composite material of the present invention, which can greatly improve the interlaminar strength and flexural strength of the polyamide composite material.

[0044] Examples 9-12 The weight percentages of the various raw materials of the continuous fiber reinforced polyamide composite materials for 3D printing obtained in Examples 9-12 and the performance data of the obtained 3D printed polyamide composite materials are shown in Table 2 below.

[0045] Table 2 Weight percentage and performance data of each raw material of the continuous fiber reinforced polyamide composite material for 3D printing obtained in Examples 9-12 From the data in Table 2, it can be seen that when a small amount of sodium tetraborate decahydrate exists in the system, the interlaminar strength of the material can be further improved, and the bending strength can be maintained. However, the content of sodium tetraborate decahydrate is preferably not more than 0.5%.

[0046] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A continuous fiber reinforced polyamide composite material for 3D printing, characterized in that It comprises component A and component B, wherein component A comprises the following components in percentage by weight: Polyamide PA12 59%-79.9%; Polyamide PA1012 5-10% Polyamide copolymer cPA 15%-30%; Antioxidant 0%-1%; Component B is continuous fiber, which is carbon fiber or glass fiber, and the amount of component B is 10-30% of the weight of component A; The polyamide copolymer cPA is copolymerized by monomer A, monomer B and monomer C, wherein monomer A is a blend of decanediamine and aliphatic dibasic acid; monomer B is a mixture of polytetrahydrofuran diamine and aliphatic dibasic acid; monomer C is a mixture of alicyclic monomer and aliphatic dibasic acid, wherein the alicyclic monomer is one of MACM and PACM.

2. The continuous fiber reinforced polyamide composite material for 3D printing according to claim 1, characterized in that It comprises component A and component B, wherein component A comprises the following components in percentage by weight: Polyamide PA12 64.6-74.9%; Polyamide PA1012 5-10%; Polyamide copolymer cPA 20-25%; Antioxidant 0-0.5%; Component B is continuous fiber, which is carbon fiber or glass fiber. The amount of component B is 10-30% of the weight of component A.

3. The continuous fiber reinforced polyamide composite material for 3D printing according to claim 1 or 2, characterized in that: The polyamide copolymer cPA is copolymerized by monomer A, monomer B and monomer C, wherein the weight ratios of monomer A, monomer B and monomer C to the total weight of the three monomers are 60%-80%, 10%-20% and 10-20% respectively; wherein the monomer A is a blend of decanediamine and an aliphatic dibasic acid, and the molar ratio of decanediamine to the aliphatic dibasic acid adipic acid is (0.98-1.02):1; the monomer B is a polytetrahydrofuran diamine with a molecular weight of 900-1500 and A mixture of aliphatic dibasic acids, the molar ratio of polytetrahydrofuran diamine to aliphatic dibasic acid is (0.98-1.02):1; the monomer C is a mixture of alicyclic monomer and aliphatic dibasic acid, the alicyclic monomer is one of MACM and PACM, and the molar ratio of alicyclic monomer to aliphatic dibasic acid is (0.98-1.02):1; the aliphatic dibasic acids in monomer A, monomer B and monomer C are all relatively independently at least one of succinic acid, adipic acid and azelaic acid.

4. The continuous fiber reinforced polyamide composite material for 3D printing according to claim 1 or 2, characterized in that: The viscosity index of the polyamide copolymer cPA is 140-220.

5. The continuous fiber reinforced polyamide composite material for 3D printing according to claim 1 or 2, characterized in that: The polyamide copolymer cPA is prepared by the following method: Step 1: Add monomers A, B, C and catalyst into a polymerization reactor; Step 2: Nitrogen purging, the pressure is maintained at 0.3-1.0MPa; Step 3: Heat the solution to 100-140°C and stir for 1-3h; Step 4: Continue to heat up to 220-260℃ and maintain pressure for 1-3h; Step 5: The pressure is reduced to 0 MPa, and the polyamide copolymer cPA is obtained after vacuuming for 5-240 minutes according to the required viscosity.

6. The continuous fiber reinforced polyamide composite material for 3D printing according to claim 1 or 2, characterized in that: The viscosity index of the polyamide PA12 is 100-250.

7. The continuous fiber reinforced polyamide composite material for 3D printing according to claim 1 or 2, characterized in that: The viscosity index of the polyamide PA1012 is 150-220.

8. The continuous fiber reinforced polyamide composite material for 3D printing according to claim 1 or 2, characterized in that: The component A also contains 0.1%-0.5% by weight of sodium tetraborate decahydrate.

9. A method for preparing a continuous fiber reinforced polyamide composite material for 3D printing according to any one of claims 1 to 8, characterized in that The following steps are involved: The raw materials of component A are melt-blended to obtain an impregnation liquid; the continuous fiber of component B is impregnated in the impregnation liquid, and then shaped and cooled to obtain a continuous fiber prepreg for 3D printing; the continuous fiber prepreg for 3D printing is then printed by a 3D printer to obtain a continuous fiber reinforced polyamide composite material for 3D printing.

10. Use of the continuous fiber reinforced polyamide composite material for 3D printing according to any one of claims 1 to 8 in shoe materials and plates.

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