A particle extrusion type carbon fiber reinforced 3D printing material and its preparation method and application

Abstract

The present invention relates to the field of 3D printing technology, and in particular to a particle extruded carbon fiber reinforced 3D printing material, a preparation method thereof, and an application thereof. The present invention provides a particle extruded carbon fiber reinforced 3D printing material, which comprises 0 to 40 parts of modified carbon fiber and 60 to 100 parts of polyamide in terms of mass fractions, and the amount of the modified carbon fiber is not 0; the modified carbon fiber is obtained by sequentially subjecting the carbon fiber to oxidation treatment and coupling agent treatment. After the present invention modifies the carbon fiber, it can effectively modify the interface between the carbon fiber and the polymer material, and improve the compatibility of the carbon fiber reinforced polymer material; polyamide can effectively fill the microstructure formed by oxidation of the carbon fiber surface, and improve the interfacial bonding force between the polymer and the carbon fiber from a physical level.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a particle extrusion type carbon fiber reinforced 3D printing material and a preparation method and application thereof. Background Art

[0002] Additive manufacturing technology, commonly known as 3D printing, is a rapid prototyping technology. It is based on digital model files and slices, and builds objects layer by layer by heating molten polymer 3D printing wire. It can not only effectively improve material utilization, but also quickly manufacture complex structures that are difficult to process with traditional processes. However, fused deposition printing has high requirements for material rigidity, wire diameter stability, and wire surface cleanliness. Only a few materials can meet the requirements and be commercially produced. Therefore, there are fewer types of wires to choose from and the preparation cost is high. The preparation of corresponding reinforced composite wires is more difficult and more expensive, and the mechanical properties of printed products cannot be further improved. At the same time, the flow rate and speed of fused deposition printing are limited by the diameter and feed speed of the printing wire, which hinders the improvement of production efficiency. The new melt extrusion 3D printer uses granular raw materials as consumables, does not require secondary processing of wire making, and reduces unnecessary time and cost consumption. The introduction of granular melt extrusion 3D printers will improve the performance of products and expand the application scope of 3D printing.

[0003] With the development of 3D printing and the needs of the industry, pure materials are difficult to meet the requirements of mechanical properties during the preparation and modification of materials. Therefore, carbon fiber reinforcement, blending and compatibility modification are important and necessary means to develop new granular 3D printing materials. However, the inert carbon fiber surface and polar polyamide are prone to interfacial debonding, resulting in the failure of the reinforced polymer material. Therefore, the mechanical properties of the carbon fiber reinforced polymer prepared by blending are difficult to meet the use requirements. Summary of the invention

[0004] The object of the present invention is to provide a particle extruded carbon fiber reinforced 3D printing material and a preparation method and application thereof, wherein the 3D printing material can meet higher mechanical performance requirements.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a particle extrusion type carbon fiber reinforced 3D printing material, wherein the raw materials for preparation include 0 to 40 parts of modified carbon fiber and 60 to 100 parts of polyamide in terms of mass fraction, and the amount of the modified carbon fiber is not 0;

[0007] The modified carbon fiber is obtained by sequentially subjecting the carbon fiber to oxidation treatment and coupling agent treatment.

[0008] Preferably, the polyamide comprises low-viscosity polyamide and high-viscosity polyamide;

[0009] The relative viscosity of the low-viscosity polyamide is less than 2.47, and the relative viscosity of the high-viscosity polyamide is greater than 2.7.

[0010] Preferably, the mass ratio of the low-viscosity polyamide to the high-viscosity polyamide is (0-35):(100-65).

[0011] Preferably, the method for preparing the modified carbon fiber comprises the following steps:

[0012] After mixing the carbon fiber and the oxidant, performing an oxidation treatment to obtain an oxidized carbon fiber;

[0013] The oxidized carbon fiber is immersed in a coupling agent solution and then cured to obtain the modified carbon fiber.

[0014] Preferably, the oxidant includes hydrogen peroxide, nitric acid or sulfuric acid;

[0015] The temperature of the oxidation treatment is room temperature, and the time is 5 to 60 seconds.

[0016] Preferably, the concentration of the coupling agent solution is 0.005-0.1 mol / L;

[0017] The coupling agent in the coupling agent solution is one or more of an aminosilane coupling agent, an epoxysilane coupling agent and an acyloxysilane coupling agent.

[0018] Preferably, the coupling agent is one or more of γ-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, N-2-aminoethyl-3-aminopropylmethyldimethoxysilane, γ-diethylenetriaminepropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-(2,3-epoxypropyloxy)propyltriethoxysilane, 3-(2,3-epoxypropyloxy)propylmethyldimethoxysilane and vinylacyloxysilane.

[0019] The present invention also provides a method for preparing the particle extrusion type carbon fiber reinforced 3D printing material described in the above technical solution, comprising the following steps:

[0020] After the modified carbon fiber and polyamide are mixed, extrusion, feeding and pulling pelletizing are performed in sequence to obtain the pellet extrusion type carbon fiber reinforced 3D printing material.

[0021] Preferably, the extrusion speed is 250-400 rpm, the feeding speed is 10-50 kg / h, and the traction pelletizing speed is 600-800 rpm.

[0022] The present invention also provides the application of the particle extruded carbon fiber reinforced 3D printing material described in the above technical solution or the particle extruded carbon fiber reinforced 3D printing material prepared by the preparation method described in the above technical solution in the field of 3D printing.

[0023] The present invention provides a particle extruded carbon fiber reinforced 3D printing material. The raw materials for preparation include 0 to 40 parts of modified carbon fiber and 60 to 100 parts of polyamide in parts by mass, and the amount of the modified carbon fiber is not 0; the modified carbon fiber is obtained by sequentially subjecting the carbon fiber to oxidation treatment and coupling agent treatment.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1) After the carbon fiber is modified by the present invention, a large number of active functional groups (hydroxyl groups) can be obtained on the surface of the carbon fiber, which is helpful for subsequent surface treatment and combination, and can effectively modify the interface between the carbon fiber and the polymer material, and improve the compatibility of the carbon fiber reinforced polymer material;

[0026] 2) The polyamide described in the present invention can effectively fill the microstructure formed by oxidation on the surface of carbon fiber, thereby improving the interface bonding between the polymer and the carbon fiber from a physical level. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the preparation process of the particle extrusion type carbon fiber reinforced 3D printing material of the present invention, and the 3D printing and prepared test piece in the embodiment;

[0028] Figure 2 The interface enhancement mechanism of the particle extrusion carbon fiber reinforced 3D printing material described in the present invention;

[0029] Figure 3 This is an interface morphology diagram of the modified carbon fiber and polyamide in the particle extruded carbon fiber reinforced 3D printing material described in Example 2. DETAILED DESCRIPTION

[0030] The present invention provides a particle extrusion type carbon fiber reinforced 3D printing material, wherein the raw materials for preparation include 0 to 40 parts of modified carbon fiber and 60 to 100 parts of polyamide in terms of mass fraction, and the amount of the modified carbon fiber is not 0;

[0031] The modified carbon fiber is obtained by sequentially subjecting the carbon fiber to oxidation treatment and coupling agent treatment.

[0032] In the present invention, unless otherwise specified, all preparation raw materials are commercially available products well known to those skilled in the art.

[0033] In terms of weight percentage, the particle extruded carbon fiber reinforced 3D printing material of the present invention includes 0 to 40 parts of modified carbon fiber, preferably 5 to 30 parts, and more preferably 14 to 25 parts.

[0034] In the present invention, the method for preparing the modified carbon fiber comprises the following steps:

[0035] After mixing the carbon fiber and the oxidant, performing an oxidation treatment to obtain an oxidized carbon fiber;

[0036] The oxidized carbon fiber is immersed in a coupling agent solution and then cured to obtain the modified carbon fiber.

[0037] The present invention mixes carbon fiber and an oxidant, and then performs oxidation treatment to obtain the oxidized carbon fiber.

[0038] In the present invention, the mixing process preferably includes subjecting the carbon fibers to a high temperature treatment before mixing. The temperature of the high temperature treatment is preferably 350 to 550°C, more preferably 400 to 500°C, and most preferably 420 to 480°C. The time is preferably 5 to 15 minutes, and more preferably 8 to 12 minutes. In the present invention, the purpose of the high temperature treatment is to remove the sizing agent on the surface of the commercial carbon fibers.

[0039] In the present invention, the oxidant preferably includes hydrogen peroxide, nitric acid or sulfuric acid, more preferably hydrogen peroxide; the mass concentration of the hydrogen peroxide is preferably 3-25%, more preferably 5-20%, most preferably 8-13%; the mass concentration of the nitric acid is preferably 5-30%, more preferably 10%; the mass concentration of the sulfuric acid is preferably 5-20%, more preferably 10%.

[0040] In the present invention, the mass ratio of the carbon fiber to the oxidant is preferably 1:(5-30), more preferably 1:(5-20), and most preferably 1:(10-15).

[0041] In the present invention, the temperature of the oxidation treatment is preferably room temperature, and the time is preferably 5 to 60 s, more preferably 10 to 50 s, and more preferably 10 to 30 s.

[0042] In the present invention, the oxidation treatment can obtain a large number of active functional groups (hydroxyl groups) on the surface of the carbon fiber, and at the same time, the carbon fiber is oxidatively etched to form some holes, which are helpful for mechanical locking with polyamide.

[0043] After obtaining the oxidized carbon fiber, the present invention immerses the oxidized carbon fiber in a coupling agent solution and then solidifies it to obtain the modified carbon fiber.

[0044] In the present invention, the concentration of the coupling agent solution is preferably 0.005-0.1 mol / L, more preferably 0.008-0.016 mol / L, and most preferably 0.012-0.014 mol / L. In the present invention, the solvent in the coupling agent solution is preferably an ethanol aqueous solution, and the volume ratio of ethanol to water in the ethanol aqueous solution is preferably 3:1. In the present invention, the role of the ethanol aqueous solution is to make the coupling agent fully dispersed and hydrolyzed to generate reactive silanol and corresponding alcohol.

[0045] In the present invention, the coupling agent in the coupling agent solution is preferably one or more of an aminosilane coupling agent, an epoxysilane coupling agent and an acyloxysilane coupling agent, and more preferably γ-aminopropyltrimethoxysilane (KH-540), 3-aminopropyltriethoxysilane (KH-550), N-2-aminoethyl-3-aminopropyltrimethoxysilane (KH-792), N-2-aminoethyl-3-aminopropylmethyldimethoxysilane (Si-602), γ-diethylenetriaminepropylmethyldimethoxysilane (Si-60 3), one or more of γ-aminopropylmethyldiethoxysilane (Si-902), 3-glycidyloxypropyltrimethoxysilane (KH-560), 3-(2,3-epoxypropyloxy)propyltriethoxysilane (KH-561), 3-(2,3-epoxypropyloxy)propylmethyldimethoxysilane (KH-562) and vinylacyloxysilane; when the coupling agent is two or more of the above-mentioned specific selections, the present invention has no special limitation on the ratio of the above-mentioned specific substances, and they can be mixed in any ratio.

[0046] In the present invention, the volume ratio of the mass of the oxidized carbon fiber to the coupling agent solution is preferably 1 g:(5-20) mL, more preferably 1 g:(10-15) mL, and most preferably 1 g:10 mL.

[0047] In the present invention, the immersion temperature is preferably room temperature; the immersion time is preferably 5 to 60 min, more preferably 10 to 50 min, and most preferably 20 to 40 min.

[0048] In the present invention, during the impregnation process, the carbon fiber surface treated with a coupling agent, the siloxane of the coupling agent is diluted and a hydroxyl group is generated at one end, which is adsorbed on the carbon fiber having a large number of active functional groups (hydroxyl groups) under the action of hydrogen bonds, indicating that the epoxy functional group at the other end is easy to react with polyamide; under the joint action of mechanical locking and chemical surface modification, the bonding force between the carbon fiber and the polyamide is enhanced.

[0049] The active functional groups on the surface of the carbon fiber and the hydrolyzed coupling agent form chemical adsorption.

[0050] In the present invention, the curing temperature is preferably 90-115°C, more preferably 95-110°C, and most preferably 100-105°C; the curing time is preferably 5-60 min, more preferably 10-50 min, and most preferably 20-30 min.

[0051] In the present invention, dehydration condensation occurs during the curing process, and the coupling agent is cured on the surface of the carbon fiber.

[0052] Based on the mass fraction of the carbon fiber, the particle extruded carbon fiber reinforced 3D printing material of the present invention also includes 60 to 100 parts of polyamide, preferably 70 to 90 parts, and more preferably 75 to 85 parts. In the present invention, the polyamide preferably includes low-viscosity polyamide and high-viscosity polyamide; the relative viscosity of the low-viscosity polyamide is preferably <2.47, more preferably 1.99 to 2.47; the relative viscosity of the high-viscosity polyamide is preferably >2.7, more preferably 2.7 to 3.2. In the present invention, the mass ratio of the low-viscosity polyamide to the high-viscosity polyamide is preferably (0 to 35): (100 to 65), more preferably (5 to 30): (95 to 70), and most preferably (10 to 20): (90 to 80). In the present invention, the high-viscosity polyamide is preferably H-polyamide-6; the low-viscosity polyamide is preferably L-polyamide-6.

[0053] In the present invention, the L-polyamide-6 has better fluidity, and its melt can interlock with the microstructure etched on the surface of the carbon fiber; while the H-polyamide-6 is mainly used to improve the strength of the composite material. And the functional groups of the polyamide can react with the functional groups of the coupling agent under high temperature conditions to form chemical bonds, thereby improving the interface bonding between the polyamide-6 material and the carbon fiber. In the present invention, the mass ratio of the low-viscosity polyamide and the high-viscosity polyamide is controlled within the above range, which can ensure that the viscosity of the mixed material is within a reasonable range.

[0054] In the present invention, the interface enhancement mechanism of the particle extrusion carbon fiber reinforced 3D printing material is taken as an example. The carbon fiber on the surface of the coupling agent is adsorbed on the surface of the carbon fiber by one end of the siloxane of the coupling agent, and the epoxy functional group at the other end is easily reacted with the polyamide resin (such as Figure 2 shown).

[0055] The present invention also provides a method for preparing the particle extrusion type carbon fiber reinforced 3D printing material described in the above technical solution, comprising the following steps:

[0056] After the modified carbon fiber and polyamide are mixed, extrusion, feeding and pulling pelletizing are performed in sequence to obtain the pellet extrusion type carbon fiber reinforced 3D printing material.

[0057] The present invention does not have any special limitation on the mixing process, and the mixing process may be carried out using a process well known to those skilled in the art.

[0058] In the present invention, the extruder used for extrusion includes a feed section, a feeding section, a plasticizing section and an extrusion section arranged in sequence. The temperature of the feed section is preferably 220-235°C, the temperature of the feeding section is preferably 230-240°C, the temperature of the plasticizing section is preferably 240-255°C, and the temperature of the die section is preferably 240-250°C.

[0059] In the present invention, the extrusion speed is preferably 250-400 rpm, more preferably 300-350 rpm; the tailing speed is preferably 10-50 kg / h, more preferably 20-40 kg / h; the traction pelletizing speed is preferably 600-800 rpm, more preferably 650-750 rpm.

[0060] In the present invention, the above preparation method can obtain a granular material with uniform and certain diameter. The carbon fiber is wrapped by an interfacial modifier, and during the extrusion process, the functional groups on the surface of the carbon fiber realize covalent bonds and / or chemical reactions with the polymer, and finally achieve the purpose of improving the compatibility between the carbon fiber and the polymer and between the polymers themselves.

[0061] The present invention also provides the use of the particle extruded carbon fiber reinforced 3D printing material described in the above technical solution or the particle extruded carbon fiber reinforced 3D printing material prepared by the preparation method described in the above technical solution in the field of 3D printing. The present invention does not have any special limitation on the method of the application, and the method well known to those skilled in the art can be used.

[0062] The particle extruded carbon fiber reinforced 3D printing material provided by the present invention and its preparation method and application are described in detail below in conjunction with the embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0063] Example 1

[0064] The carbon fiber is subjected to a high temperature treatment at 400°C for 10 minutes to remove the sizing agent on the surface of the commercial carbon fiber, and then subjected to an oxidation treatment in a 10% mass concentration hydrogen peroxide solution for 1 minute to obtain an oxidized carbon fiber;

[0065] Mix 25 mL of a coupling agent (specific types are shown in Table 1) and 4985 mL of an ethanol aqueous solution (the volume ratio of ethanol to water is 3:1), and stir for 30 min until the mixture is uniform to obtain a coupling agent solution (concentration is 0.021 mol / L);

[0066] 250 g of the oxidized carbon fiber was placed in 2500 mL of the coupling agent solution for impregnation (the impregnation temperature was 25° C. and the time was 10 min), and then dried and cured in an oven (the drying temperature was 110° C. and the time was 20 min) to obtain a modified carbon fiber;

[0067] like Figure 1 As shown in (a), modified carbon fiber and polyamide (L-polyamide-6 with a relative viscosity of 2.2 and H-polyamide-6 with a relative viscosity of 2.85 in a mass ratio of 8:92) are mixed, and extrusion (rotation speed is 300 rpm, the temperature of the feed section is 220°C, the temperature of the feeding section is 240°C, the temperature of the plasticizing section is 255°C, and the temperature of the die section is 245°C), feeding (rotation speed is 6kg / h (the mass percentage of carbon fiber is 15wt%), 10kg / h (the mass percentage of carbon fiber is 25wt%) and 15kg / h (the mass percentage of carbon fiber is 32wt%)) and traction pelletizing (rotation speed is 650 rpm) to obtain a particle extrusion type carbon fiber reinforced 3D printing material (the mass percentage of modified carbon fiber is shown in Table 1).

[0068] Comparative Example 1

[0069] Refer to Example 1, except that no modification treatment is performed, that is, the process of immersing in a coupling agent solution is not included.

[0070] like Figure 1 As shown in (b), the particle extrusion type carbon fiber reinforced 3D printing material described in Example 1 and Comparative Example 1 was used to prepare a print (length 165 mm, narrow width 19 mm, total width 29 mm, thickness 3.2 mm), and the preparation parameters were: extrusion temperature 300 ° C, extrusion line width 4 mm, layer height 0.3 mm, and line speed 40 mm / s; the test conditions were: constant temperature and humidity for 48 hours, and the stretching rate was 25 mm / s. The test results are shown in Table 1:

[0071] Table 1: Tensile strength of printed parts of Example 1 and Comparative Example 1 (MPa)

[0072]

[0073] Note: CF stands for carbon fiber;

[0074] Example 2

[0075] The carbon fiber is subjected to a high temperature treatment at 400°C for 10 minutes to remove the sizing agent on the surface of the commercial carbon fiber, and then subjected to an oxidation treatment in a 10% mass concentration hydrogen peroxide solution for 1 minute to obtain an oxidized carbon fiber;

[0076] Mix 25 mL of a coupling agent (specific types are shown in Table 2) and 2475 mL of an ethanol aqueous solution (the volume ratio of ethanol to water is 3:1), and stir for 30 min until the mixture is uniform to obtain a coupling agent solution (concentration is 0.043 mol / L);

[0077] 100 g of the oxidized carbon fiber was immersed in 1000 mL of the coupling agent solution (immersion temperature was room temperature and time was 10 min), and then dried and cured in an oven (drying temperature was 110° C. and time was 20 min) to obtain modified carbon fiber;

[0078] like Figure 1 As shown in (a), modified carbon fiber and polyamide (L-polyamide-6 with a relative viscosity of 2.2 and H-polyamide-6 with a relative viscosity of 2.85 in a mass ratio of 8:92) are mixed, and extrusion (rotation speed is 300 rpm, the temperature of the feed section is 220°C, the temperature of the feeding section is 240°C, the temperature of the plasticizing section is 255°C, and the temperature of the die section is 245°C) is carried out in sequence, feeding (rotation speed is 10 kg / h) and traction pelletizing (rotation speed is 650 rpm) to obtain a particle extrusion type carbon fiber reinforced 3D printing material (the mass percentage of the modified carbon fiber is shown in Table 2).

[0079] The printout and test conditions refer to Example 1, and the test results are shown in Table 2:

[0080] Table 2: Tensile strength of printed parts of Example 2 and Comparative Example 1 (MPa)

[0081]

[0082] Figure 2 The interface morphology of modified carbon fiber and polyamide in the prepared particle extruded carbon fiber reinforced 3D printing material with coupling agent KH792 and CF content of 25% is shown in the figure. Figure 2 It can be seen that the carbon fibers are uniformly dispersed in the polyamide matrix without obvious agglomeration, and the carbon fibers are well embedded in the matrix without obvious debonding and holes.

[0083] Example 3

[0084] The carbon fiber is subjected to a high temperature treatment at 400°C for 10 minutes to remove the sizing agent on the surface of the commercial carbon fiber, and then subjected to an oxidation treatment in a 10% mass concentration hydrogen peroxide solution for 1 minute to obtain an oxidized carbon fiber;

[0085] Mix 20 mL of coupling agent (specific types are shown in Table 3) and 980 mL of ethanol aqueous solution (the volume ratio of ethanol to water is 3:1), and stir for 30 min until the mixture is uniform to obtain a coupling agent solution (concentration is 0.086 mol / L);

[0086] 100 g of the oxidized carbon fiber was immersed in 1000 mL of the coupling agent solution (immersion temperature was room temperature and time was 10 min), and then dried and cured in an oven (drying temperature was 110° C. and time was 20 min) to obtain modified carbon fiber;

[0087] like Figure 1 As shown in (a), modified carbon fiber and polyamide (L-polyamide-6 with a viscosity of 2.2 and H-polyamide-6 with a viscosity of 2.85 in a mass ratio of 8:92) are mixed, and extrusion (rotation speed is 300 rpm, the temperature of the feed section is 220°C, the temperature of the feeding section is 240°C, the temperature of the plasticizing section is 255°C, and the temperature of the die section is 245°C), feeding (rotation speed is 6kg / h (the mass percentage of carbon fiber is 15wt%), 10kg / h (the mass percentage of carbon fiber is 25wt%) and 15kg / h (the mass percentage of carbon fiber is 32wt%)) and traction pelletizing (rotation speed is 650 rpm) to obtain a particle extrusion type carbon fiber reinforced 3D printing material (the mass percentage of modified carbon fiber is shown in Table 3).

[0088] The printout and test conditions refer to Example 1, and the test results are shown in Table 3:

[0089] Table 3 Printed Part Tensile Strength (MPa) of Example 3 and Comparative Example 1

[0090]

[0091]

[0092] Example 4

[0093] The carbon fiber is subjected to a high temperature treatment at 400°C for 10 minutes to remove the sizing agent on the surface of the commercial carbon fiber, and then subjected to an oxidation treatment in a 10% mass concentration hydrogen peroxide solution for 1 minute to obtain an oxidized carbon fiber;

[0094] Mix 25 mL of coupling agent (specific type: KH792) and 2475 mL of ethanol aqueous solution (volume ratio of ethanol to water is 3:1), and stir for 40 min until the mixture is uniform to obtain a coupling agent solution (concentration: 0.043 mol / L);

[0095] 100 g of the oxidized carbon fiber was immersed in 1000 mL of the coupling agent solution (immersion temperature was room temperature, time was 10 min), and then dried and cured in an oven (drying temperature was 100° C., time was 15 min), to obtain modified carbon fiber;

[0096] The modified carbon fiber and polyamide (the viscosity and proportion of L-polyamide-6 and H-polyamide-6 are shown in Table 4) were mixed, and extrusion (rotation speed was 300 rpm, the temperature of the feed section was 220°C, the temperature of the feeding section was 240°C, the temperature of the plasticizing section was 255°C, and the temperature of the die section was 245°C) was performed in sequence, feeding (rotation speed was 10 kg / h) and traction pelletizing (rotation speed was 650 rpm) were performed to obtain a particle extruded carbon fiber reinforced 3D printing material (the content of modified carbon fiber was 25wt%).

[0097] The printout and test conditions refer to Example 1, and the test results are shown in Table 4:

[0098] Table 4: Tensile strength of printed parts of Example 4 (MPa)

[0099]

[0100]

[0101] As shown in Table 4, the viscosity of the fixed H-polyamide component is 2.85, and the addition of an appropriate amount of low-viscosity component (8 wt % is optimal) helps to improve the mechanical properties of the printed part.

[0102] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A particle extruded carbon fiber reinforced 3D printing material, characterized in that: The raw materials include 5 to 40 parts of modified carbon fiber and 100 parts of polyamide in terms of weight. The polyamide includes low-viscosity polyamide and high-viscosity polyamide; The relative viscosity of the low-viscosity polyamide is 1.99 to 2.47, and the relative viscosity of the high-viscosity polyamide is 2.7 to 3.2; The mass ratio of the low-viscosity polyamide to the high-viscosity polyamide is (0-8):(100-92), and the mass of the low-viscosity polyamide is not 0; The modified carbon fiber is obtained by sequentially subjecting the carbon fiber to oxidation treatment and coupling agent treatment; The oxidation treatment temperature is room temperature and the time is 5 to 60 seconds; The concentration of the coupling agent solution used in the coupling agent treatment is 0.005-0.1 mol / L.

2. The particle extruded carbon fiber reinforced 3D printing material according to claim 1, characterized in that: The preparation method of the modified carbon fiber comprises the following steps: After mixing the carbon fiber and the oxidant, performing an oxidation treatment to obtain an oxidized carbon fiber; The oxidized carbon fiber is immersed in a coupling agent solution and then cured to obtain the modified carbon fiber.

3. The particle extruded carbon fiber reinforced 3D printing material according to claim 2, characterized in that: The oxidant includes hydrogen peroxide, nitric acid or sulfuric acid.

4. The particle extruded carbon fiber reinforced 3D printing material according to claim 2, characterized in that: The concentration of the coupling agent solution is 0.005-0.1 mol / L; The coupling agent in the coupling agent solution is one or more of an aminosilane coupling agent, an epoxysilane coupling agent and an acyloxysilane coupling agent.

5. The particle extruded carbon fiber reinforced 3D printing material according to claim 4, characterized in that: The coupling agent is one or more of γ-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, N-2-aminoethyl-3-aminopropylmethyldimethoxysilane, γ-diethylenetriaminepropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-(2,3-epoxypropyloxy)propyltriethoxysilane, 3-(2,3-epoxypropyloxy)propylmethyldimethoxysilane and vinylacyloxysilane.

6. The method for preparing a particle extrusion type carbon fiber reinforced 3D printing material according to any one of claims 1 to 5, characterized in that: The following steps are involved: After the modified carbon fiber and polyamide are mixed, extrusion, feeding and pulling pelletizing are performed in sequence to obtain the pellet extrusion type carbon fiber reinforced 3D printing material.

7. The preparation method according to claim 6, characterized in that: The extrusion speed is 250-400 rpm, the feeding speed is 10-50 kg / h, and the traction pelletizing speed is 600-800 rpm.

8. Application of the particle extruded carbon fiber reinforced 3D printing material according to any one of claims 1 to 5 or the particle extruded carbon fiber reinforced 3D printing material prepared by the preparation method according to claim 6 or 7 in the field of 3D printing.

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