A continuous fiber reinforced polyamide composite material for 3D printing, its preparation and application

Abstract

The present invention belongs to the field of composite materials, and discloses a polyamide composite material for 3D printing continuous fiber reinforcement, its preparation method and application. The polyamide composite material comprises component A and component B, wherein component A comprises the following components in weight percentages: polyamide PA12 59% - 79.9%; polyamide PA1012 5 - 10%; polyamide copolymer cPA 15% - 30%; antioxidant 0% - 1%; component B is carbon fiber or glass fiber, and the dosage of component B is 10 - 30% of the weight of component A. Component A may further include sodium tetraborate decahydrate. The polyamide composite material for 3D printing continuous fiber reinforcement of the present invention has higher interlayer strength and flexural strength, enabling the 3D printing continuous carbon fiber reinforced material to be applicable 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.

Description

Technical Field

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

[0002] Using continuous fiber reinforced thermoplastic resin for 3D printing is a current research hotspot, mainly aiming to greatly improve the strength of 3D printing materials. The main method adopted is to directly introduce a continuous fiber bundle into the nozzle of the printer, and the continuous fiber bundle and the 3D printing filament pass through the nozzle of the printer simultaneously for printing. 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. Research shows that optimizing material properties can significantly improve the interlayer strength. Nylon 12 is a resin material that has been screened out in the current market and can better balance the interlayer strength and other properties, 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 continuous fibers, the performance improvement of the interlayer strength will be further restricted. Moreover, due to its low melting point and strength, the strength of nylon 12 is also limited in the orientation perpendicular to the layer. Summary of the Invention

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

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

[0005] Another object of the present invention is to provide an application of the above-mentioned polyamide composite material reinforced with continuous fibers for 3D printing with higher interlayer strength.

[0006] The object of the present invention is achieved by the following solutions:

[0007] A polyamide composite material reinforced with continuous fibers for 3D printing, which comprises component A and component B, wherein component A comprises the following components in weight percentage:

[0008] Polyamide PA12 59%-79.9%;

[0009] Polyamide PA1012 5-10%;

[0010] Polyamide copolymer cPA 15%-30%;

[0011] Antioxidant: 0% - 1%;

[0012] The second component is continuous fiber, and the continuous fiber is carbon fiber or glass fiber. The dosage of the second component is 10% - 30% of the weight of the first component.

[0013] Preferably, the polyamide composite material for 3D printing continuous fiber reinforcement comprises a first component and a second component. The first component comprises the following components in weight percentages:

[0014] Polyamide PA12: 64.6% - 74.9%;

[0015] Polyamide PA1012: 5% - 10%;

[0016] Polyamide copolymer cPA: 20% - 25%;

[0017] Antioxidant: 0% - 0.5%;

[0018] The second component is continuous fiber, and the continuous fiber is carbon fiber or glass fiber. The dosage of the second component is 10% - 30% of the weight of the first component.

[0019] The polyamide copolymer cPA is copolymerized from monomer A, monomer B, and monomer C. The mass ratios of monomer A, monomer B, and monomer C to the total mass of the three monomers (monomer A, monomer B, and monomer C) are 60% - 80%, 10% - 20%, and 10% - 20% respectively. Wherein, monomer A is a blend of decanediamine and aliphatic dibasic acid, and the molar ratio of decanediamine to aliphatic dibasic acid adipic acid is (0.98 - 1.02):1; monomer B is a mixture of polytetrahydrofuran diamine with a molecular weight of 900 - 1500 and aliphatic dibasic acid, and the molar ratio of polytetrahydrofuran diamine to aliphatic dibasic acid is (0.98 - 1.02):1; monomer C is a mixture of alicyclic monomer and aliphatic dibasic acid, and 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 each independently at least one of succinic acid, adipic acid, and azelaic acid.

[0020] 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 ratios of monomer A, monomer B, and monomer C to the total mass of the three monomers (monomer A, monomer B, and monomer C) are 70%, 10%, and 20% respectively.

[0021] The polyamide PA copolymer is prepared by the following method:

[0022] Step 1: Add monomers A, B, C and the catalyst into the polymerization kettle;

[0023] Step 2: Purge with nitrogen and maintain the pressure at 0.3 - 1.0 MPa;

[0024] Step 3: Heat the solution to 100 - 140 °C and stir at a constant temperature for 1 - 3 h;

[0025] Step 4: Continue to heat to 220 - 260 °C and maintain the pressure for 1 - 3 h;

[0026] Step 5: Release the pressure to 0 MPa, evacuate for 5 - 240 min according to the required viscosity, and then discharge to obtain the polyamide copolymer cPA.

[0027] The catalyst described in Step 1 is one or a mixture of two of hypophosphorous acid, phosphoric acid, and hypophosphite. The dosage of the catalyst satisfies: the weight of the catalyst accounts for 0.05 - 0.2% of the total weight of the three monomers.

[0028] Preferably, the viscosity number (VN) of the polyamide copolymer cPA is 140 - 220, preferably 190 - 220.

[0029] Preferably, the viscosity number of the polyamide PA1012 is 150 - 220, preferably 160 - 180.

[0030] Preferably, the viscosity number of the polyamide PA12 is 100 - 250.

[0031] The antioxidant is at least one of hindered phenol antioxidants, hindered amine antioxidants, and cuprous salt antioxidants, preferably antioxidant 1098.

[0032] Preferably, the component A of the polyamide composite may further contain 0.1% - 0.5% by weight of sodium tetraborate decahydrate.

[0033] A preparation method of the above-mentioned polyamide composite material for 3D printing continuous carbon fiber reinforcement includes the following steps: melt-blend the raw materials of component A to obtain an impregnating solution; impregnate the continuous fiber of component B in the impregnating solution, then shape and cool to obtain a continuous fiber prepreg for 3D printing, and then print the continuous fiber prepreg for 3D printing with a 3D printer to obtain a polyamide composite material for 3D printing continuous carbon fiber reinforcement.

[0034] Preferably, the preparation method of the polyamide composite material for 3D printing continuous carbon fiber reinforcement specifically includes the following steps:

[0035] (1) After the continuous fiber bundle is unwound by the unwinding roller, it first passes through the pre-tensioning roller for pre-dispersion, and then the upper and lower surfaces of the continuous fiber bundle are preheated by the infrared radiation device;

[0036] (2) The preheated continuous fiber is disturbed along the direction perpendicular to the fiber dragging direction and the direction parallel to the fiber dragging direction, so that the preheated fiber bundle becomes loose, and then the yarn is spread;

[0037] (3) The raw materials of component A are melted and mixed to obtain a modified plastic melt. The plastic melt enters the wire impregnation die, and the spread fiber bundle enters the wire impregnation die at the same time to complete the impregnation process of the plastic melt on the fiber bundle. The impregnated fiber is formed through the shaping die and cooled and shaped. The shaped wire is a continuous fiber prepreg that can be used for 3D printing;

[0038] (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.

[0039] The device used in the above method for preparing a continuous carbon fiber reinforced polyamide composite material for 3D printing includes an 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 unwinding roller, twin-screw extruder, pre-tensioning roller, infrared radiation device, gas-assisted swinging device, wire impregnation die, cooling device and 3D printer.

[0040] The application of the above continuous fiber reinforced polyamide composite material for 3D printing in shoe materials and plates.

[0041] The present invention has the following advantages and beneficial effects compared with the prior art:

[0042] The continuous fiber reinforced polyamide composite material for 3D printing of the present invention has higher interlayer strength and flexural strength, enabling the 3D printed continuous carbon fiber reinforced material to be applicable 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. Description of the Drawings

[0043] Figure 1 It is a schematic diagram of the production system for 3D printing of continuous fiber impregnated reinforced resin of the present invention.

[0044] Figure 2 It is a three-dimensional structure diagram of the twin-screw extruder and the wire impregnation device of the present invention.

[0045] Figure 3 It is a partial cross-sectional view of the twin-screw extruder and the wire impregnation device of the present invention.

[0046] Figure 4It is a schematic structural diagram of the swinging device of the present invention.

[0047] Figure 5 It is a top view of the pneumatic auxiliary spreading device of the present invention.

[0048] 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 spreading device, 501-rotating roller, 6-wire impregnation device, 6a-impregnation chamber, 6b-plastic melt conveying device, 601-wavy flow channel, 602-heating rod, 603-sizing die, 604-inner haul-off roller, 7-screw extrusion device, 8-cooling device, 9-3D printing device, 901-divergent nozzle, 902-haul-off roller. Specific embodiments

[0049] The present invention will be further described in detail below with reference to the embodiments and the drawings, but the embodiments of the present invention are not limited thereto. Those not specified in the embodiments are carried out according to the conventional conditions or the conditions recommended by the manufacturer. Those reagents or instruments not specified in the manufacturer are all conventional products that can be obtained through commercial purchase.

[0050] 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".

[0051] 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.

[0052] 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.

[0053] The present invention uses a continuous fiber impregnation reinforcement 3D printing integrated device to process composite materials. Figure 1As shown, the integrated device includes an unwinding roller device 1, a pre-tensioning device 2, an infrared radiation device 3, a swinging device 4, a pneumatic auxiliary spreading device 5, a wire impregnation device 6, a twin-screw extruder 7, a cooling device 8, and a 3D printing device, and the overall layout is strip-shaped.

[0054] As Figures 1 - 5 shown, the pre-tensioning device 2 has a plurality of tensioning rollers 201 arranged in a staggered manner 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 arranged in a staggered manner to make the conveying path of the continuous fiber bundle wavy. The infrared radiation device 3 is used to preheat the pre-dispersed continuous fiber bundle. Among them, 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 swinging device 4 is located downstream of the infrared radiation device 3 and is used to disturb the preheated continuous fiber bundle along the direction perpendicular to the fiber dragging direction and the direction parallel to the fiber dragging direction. The pneumatic auxiliary spreading device 5 is located downstream of the swinging device 4. The pneumatic auxiliary spreading device 5 has a plurality of rotating rollers 501 for conveying the continuous fiber bundle, and an air flow input port is provided at the top thereof. The continuous fiber bundle is separated and unfolded by blowing high-pressure gas. The swinging device 4 includes a cam 401, a drive shaft 402, a coupling 403, and a stepping motor 404 arranged in series. The cam 401 is key-connected to the drive shaft 402. The coupling 403 and the drive shaft 402 are driven by the stepping 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, 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, facilitating subsequent yarn spreading. The swinging frequency of the cam 401 of the swinging device 4 is 10-20 r / min, and the eccentric amplitude is 10-15 mm; the plurality of rotating rollers 501 of the pneumatic auxiliary spreading device 5 are driven by a motor, the air flow speed is 2-8 m / min, the air flow direction is perpendicular to the conveying direction of the fiber bundle, and passes through between the single fibers, which can effectively avoid fiber damage. The fiber bundle is guided and limited by the plurality of rotating rollers 501. Among them, the number of rotating rollers 501 is three, which includes two guiding rollers and one limiting roller. The position of the limiting roller can be adjusted up and down. The width of the single bundle of fibers after yarn spreading by the pneumatic auxiliary spreading device 5 is 15-25 mm, and the thickness is 0.03-0.06 mm.

[0055] As Figure 1 and Figure 3As shown in the figure, X is the length direction of the wire impregnation device 6, and Y is the width direction of the wire impregnation device 6. The wire impregnation device 6 includes an impregnation chamber 6a and a plastic melt delivery device 6b arranged vertically. A fluid channel is provided in the plastic melt delivery device 6b. The twin-screw extruder 7 is connected to the wire impregnation device 6 in a parallel manner. The plastic melt delivered by the twin-screw extruder 7 enters the fluid channel of the plastic melt delivery device 6b along the length direction (X) of the wire impregnation device 6. The fluid channel has a slope and corner design, and then enters the wire impregnation device 6 along the length direction of the wire impregnation device 6 through the fluid channel. Among them, the cross-section of the plastic melt delivery device 6b along the length direction (X) of the wire impregnation 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.

[0056] The twin-screw extruder 7 includes a barrel. One end of the barrel has a feed port, and 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 screw elements in the vacuum exhaust section no longer use the conveying elements with a decreasing thread pitch, but use the conveying elements with an increasing thread pitch. The thread pitch of the vacuum exhaust section is 1.5D - 2D, where D is the inner diameter of the barrel; the thread pitch of the solid conveying section is 1D - 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 18 mm - 90 mm, the length-diameter ratio is 40 - 60, the screw speed is 0 - 500 rpm / min. The resin raw material enters from the feed port, and through the flipping, 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 delivery device 6b. Among them, the vacuum port is used to evacuate the gas in the barrel to prevent the gas from entering the fluid channel of the plastic melt delivery device 6b. The wire impregnation device 6 has a wavy flow channel 601. The wrapping angle of the wavy flow channel 601 is 300° - 450°, the gap of the wavy flow channel 601 is 8 - 10 mm. Both the top and bottom of the wavy flow channel 601 are provided with a plurality of heating rods 602. The outlet end of the wavy flow channel 601 is provided with a sizing die 603. The diameter D of the sizing die 603 is 0.7 - 1.2 mm, and the length is 15 - 20D. An internal traction roller 604 is arranged in the sizing die 603. The internal traction roller 604 is a pair of metal rollers rotating towards each other, driven by a servo motor, used to traction the fiber bundle, and through the extrusion effect, the molten resin infiltrates the fiber bundle. The traction speed of the internal traction roller 604 for the fiber bundle is the same as the wire feeding speed of the 3D printing device 9.

[0057] AsFigure 1 As shown in the figure, the 3D printing device 9 is located downstream of the wire impregnation device 6 and is used to heat and eject the impregnated fibers to obtain a 3D printed product of 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 diameter of the nozzle flow channel. The outlet of the divergent nozzle 901 is rounded, and the edge width d of the divergent nozzle 901 is 2 - 4 mm. This can ensure a larger contact area between the nozzle edge and the product surface during printing, 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, and the traction roller 902 is used to guide the continuous fibers cooled by the cooling device 8 into the 3D printing device. The printing temperature is 250 - 320 °C, and the printing speed is 50 mm / min - 2000 mm / min.

[0058] As Figure 1 shown in the figure, a cooling device 8 is also arranged between the wire impregnation device 6 and the 3D printing device 9. The cooling device 8 is used to cool and shape the impregnated fibers; an unwinding roller device 1 for winding continuous fiber bundles is also arranged upstream of the pre-tensioning device 2.

[0059] The continuous fiber described above is glass fiber or carbon fiber.

[0060] The 3D printing method using the 3D printing device of the continuous fiber reinforced thermoplastic resin melt impregnation of the present invention has the following process:

[0061] (1) After the continuous fiber bundle is unwound by the unwinding roller 1, it first passes through the pre-tensioning roller 2 for pre-dispersion, 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.

[0062] (2) The preheated continuous fiber bundle passes through the swinging device 4. Among them, the swinging device 4 makes the continuous fiber be disturbed along the direction perpendicular to the fiber dragging direction and the direction parallel to the fiber dragging direction through the eccentric rotation of the cam 401. The pneumatic auxiliary spreading device 5 provides air flow to the continuous fiber bundle, and the air flow direction is perpendicular to the conveying direction of the fiber bundle. Under the action of the initial fiber, the air flow velocity on both sides of the fiber is greater than the air flow blocked by the fiber in the middle, so that the pressure on both sides is lower. Under the action of the air pressure, the fiber bundle begins to gradually unfold to both sides, making the fiber bundle split. The final unfolded width of the fiber bundle is 15 - 25 mm, and the thickness is 0.03 - 0.06 mm.

[0063] (3)The twin-screw extruder 7 melts and mixes various raw materials according to actual requirements to obtain a modified plastic melt. The plastic melt enters the wire impregnation device 6 in a parallel direction, and the unfolded fiber bundle is introduced into the wire impregnation device 6. Under the action of the wavy channel 601, the impregnation process of the resin matrix on the fiber bundle is completed. The impregnated fiber is transported forward by the inner traction roller 604, formed through 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.

[0064] (4)After cooling, the obtained continuous fiber prepreg is transported by the wire feeding mechanism of the 3D printer 9 into the nozzle 901 of the printer. Under the heat source of the heating block, the thermoplastic resin in the prepreg is heated and melted, and is deposited on the printing platform with the fiber bundle at the same extrusion rate. Finally, a 3D printed product of continuous fiber reinforced thermoplastic composite is obtained.

[0065] In the following examples, the parameter settings of the resin-modified continuous fiber impregnation and reinforcement 3D printing integrated device are as follows: the wrapping angle of the wavy channel in the wire impregnation device 6 is 350°, the channel gap is 10 mm, the traction speed of the inner traction roller 604 is 5 m / min, the diameter D of the shaping die 603 is 1 mm, and the length is 15 times the diameter D. The swing frequency of the cam 401 in the swing device 4 is 12 r / min, and the eccentric amplitude is 10 mm. The air flow speed of the pneumatic auxiliary spreading device 5 is 5 m / min. The width of a single fiber bundle after spreading by the air-assisted swing device 5 is 20 mm, and the thickness is 0.05 mm. The preheating temperature of the infrared radiation device 3 is 180°C, the diameter of the shaping die 603 is 1 mm, and the diameter of the obtained continuous fiber prepreg is 1 mm. The divergence angle α of the nozzle of the 3D printer 9 is 45°, the length of the divergence section is 1.2 times the nozzle channel diameter, the width d of the nozzle edge is 3 mm, the printing temperature is 285°C, and the printing speed is 150 mm / min. The screw diameter of the twin-screw extruder 7 is 18 mm, the length-diameter ratio is 48, the screw speed is 200 rpm / min, the processing temperature is 250 - 270°C. In the solid conveying section, 3 screw elements with a thread pitch of 1D and 3 screw elements with a thread pitch of 2D are used. In the melting section, 1 screw element with a thread pitch of 0.5D and 4 screw elements with a thread pitch of 1D are used. In the melt conveying section, 4 screw elements with a thread pitch of 1D are used; in the vacuum exhaust section after the twin-screw vacuum port, 2 conveying screw elements with a pitch of 2D are used. In the fluid channel of the plastic melt conveying device 6b, R1 = 0.1L, R2 = 0.1L, and R3 = 1L.

[0066] Comparative Examples 1 - 5 and Examples 1 - 8

[0067] The weight parts of the raw materials of the continuous fiber-reinforced polyamide composites obtained in Comparative Examples 1-5 and Examples 1-8 for 3D printing and the performance data of the obtained 3D printed polyamide composites are shown in Table 1 below.

[0068] Table 1 Weight parts of raw materials and performance data of continuous fiber-reinforced polyamide composites obtained in Comparative Examples 1-5 and Examples 1-8 for 3D printing

[0069]

[0070] It can be seen from the comparison between Comparative Example 1 and Examples 1-8 in Table 1 that when PA1012 and polyamide copolymer cPA are added to PA12, the interlayer strength of the material can be greatly improved. At the same time, the flexural strength of the material also has a certain improvement. It can be seen from the comparison between Comparative Examples 4-5 and Examples 1-3 that when an appropriate proportion of PA1012 and polyamide copolymer cPA is added to PA12, the improvement effects on the interlayer strength and flexural strength of the material are also superior to those of adding the same amount of PA1012 or cPA alone. This 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 interlayer strength and flexural strength of the polyamide composite material.

[0071] Examples 9-12

[0072] The weight parts of the raw materials of the continuous fiber-reinforced polyamide composites obtained in Examples 9-12 for 3D printing and the performance data of the obtained 3D printed polyamide composites are shown in Table 2 below.

[0073] Table 2 Weight parts of raw materials and performance data of continuous fiber-reinforced polyamide composites obtained in Examples 9-12 for 3D printing

[0074]

[0075] It can be seen from the data in Table 2 that when there is a small amount of sodium tetraborate decahydrate in the system, the interlayer strength of the material can be further improved, and the flexural strength can be maintained. However, the content of sodium tetraborate decahydrate is preferably not more than 0.5%.

[0076] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all 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: 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 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; the monomer A is a blend of decanediamine and an aliphatic dibasic acid; the monomer B is a mixture of polytetrahydrofuran diamine and an aliphatic dibasic acid; 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.

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: The component B is continuous fiber, which is carbon fiber or glass fiber. The amount of the component B is 10-30% of the weight of the 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 The invention discloses a mixture of aliphatic dibasic acids, wherein 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, wherein 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 monomer A, the monomer B and the 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 fibers of component B are 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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