Carbon fiber 3D printing material and preparation method thereof

Abstract

The invention relates to a carbon fiber 3D printing material and a preparation method thereof, the material comprises 100 parts by weight of thermoplastic resin, 5-15 parts by weight of thermoplastic elastomer resin and 40-80 parts by weight of modified carbon fiber, the modified carbon fiber comprises a carbon fiber metal material and thermotropic liquid crystal, and the weight ratio of the carbon fiber metal material to the thermotropic liquid crystal is 1: 0.6-0.95; the method comprises the following steps: mixing the carbon fiber and the nano inorganic material in a sizing agent solution, filtering to obtain a carbon fiber metal material, mixing the carbon fiber metal material and the thermotropic liquid crystal, carrying out hot pressing and heat treatment to obtain the modified carbon fiber, and finally mixing the thermoplastic resin, the thermoplastic elastomer resin and the modified carbon fiber, heating, melting, extruding and cooling. The 3D printing material is high in toughness and good in binding force, material breaking during printing is avoided, the printed material has good mechanical performance, the high-temperature fluidity of thermoplastic resin is improved, and 3D printing forming is facilitated.

Description

Technical Field

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

[0002] 3D printing technology is an emerging technology that is rapidly developing in the manufacturing field. Its essence is additive manufacturing, which refers to a rapid manufacturing technology that fuses materials into a single shape. Based on a three-dimensional digital model file, it uses adhesive materials such as metal or plastic to construct physical objects by printing layer by layer and adding continuous layers of different shapes, facilitating rapid prototyping to obtain the desired structural components. The performance characteristics of the raw materials in 3D printing technology have a strong influence on the physical properties of the molded parts.

[0003] Common 3D printing materials include resins such as polylactic acid, acrylonitrile-butadiene-styrene copolymer, polyamide, and polyether. However, these materials have inherent drawbacks that significantly reduce their effectiveness. For example, polylactic acid has poor mechanical properties and thermal stability; acrylonitrile-butadiene-styrene copolymer produces harmful gases during printing; and polyamide and polyether have high molding temperatures. Due to their inherent properties, they shrink significantly when cooled too quickly, leading to warping. To address these issues, carbon fiber has become a common method of modifying resin materials as a reinforcing agent.

[0004] Refer to the patent publication number CN111040435A for a preparation method of a nylon carbon fiber composite powder material, which granulates the modified carbon fiber and nylon resin through double-screw extrusion to produce nylon carbon fiber pellets, thereby improving the mechanical properties and wear resistance of the nylon material. However, in actual use, the carbon fiber raw material needs to be processed at high temperature after loading and has poor fluidity at low temperatures. At the same time, the curing efficiency is slow, and there is room for improvement.

[0005] See patent publication number CN108395671A for a PEEK composite material and its manufacturing method, which directly uses an aqueous dispersion of polyetheretherketone as a modifier, pre-impregnates the widened carbon fiber bundle in the dispersion, and obtains a pre-impregnated carbon fiber bundle. This method can be used for continuous fibers, but it is easy to cause incomplete impregnation, and there is a lack of physical and chemical connection between the fiber and the matrix, resulting in poor mechanical strength. Summary of the Invention

[0006] An object of the present invention is to provide a carbon fiber 3D printing material, in particular a carbon fiber 3D printing material with good fluidity and superior mechanical properties.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A carbon fiber 3D printing material, comprising the following components:

[0009] 100 parts by weight of thermoplastic resin;

[0010] 5 to 15 parts by weight of thermoplastic elastomer resin;

[0011] 40 to 80 parts by weight of modified carbon fiber,

[0012] Wherein: the modified carbon fiber comprises carbon fiber metal material and thermotropic liquid crystal, and the weight ratio of the carbon fiber metal material to the thermotropic liquid crystal is 1:0.6-0.95,

[0013] The thermoplastic resin has the property of softening when heated and hardening when cooled, and does not undergo chemical reaction. No matter how many times the heating and cooling are repeated, this property can be maintained.

[0014] The thermoplastic elastomer resin can improve the toughness of the thermoplastic resin and reduce the warping of the finished product after printing.

[0015] The modified carbon fiber can improve the formability of the thermoplastic resin during printing, promote the crystallization of the thermoplastic resin material, improve the formability of the 3D printing material, eliminate warping, and also improve its mechanical properties.

[0016] In the above technical solution, the carbon fiber composite material comprises carbon fiber, nano inorganic material, and sizing agent, and the weight ratio of the carbon fiber to the nano inorganic material is 1:0.5-2.

[0017] The carbon fiber has excellent thermal conductivity and mechanical properties.

[0018] The nano inorganic material can conduct heat quickly, thus reducing process operation time during hot rolling and infrared heat treatment.

[0019] Further preferably, the nano-inorganic material is selected from nano-metal elements, nano-metal oxides, nano-metal carbides, nano-metal silicides, nano-metal borides, and nano-metal nitrides.

[0020] More preferably, the nano-inorganic material is nano-metal carbide or nano-metal nitride.

[0021] Still further preferably, the nano metal carbide comprises carbides of metal elements such as titanium (Ti), zirconium (Zr), tantalum (Ta), vanadium (V), molybdenum (Mo), chromium (Cr), manganese (Mn), iron (Fe), and cobalt (Co). Considering the adhesion with thermoplastic resin, titanium carbide is preferred.

[0022] Still more preferably, the nano metal nitride comprises titanium nitride, aluminum nitride, tungsten nitride, tantalum nitride, vanadium nitride, iron nitride, nickel nitride, molybdenum nitride, etc. Considering the adhesion with thermoplastic resin, titanium nitride is preferred.

[0023] Further preferably, the weight ratio of the carbon fiber and the nano-inorganic material is 1:0.8 to 1.5, such as 1:1 or 1:1.5, so as to reduce the cost and improve the strength of the 3D material after printing.

[0024] Further preferably, the sizing agent solution includes one or more of 20 to 40 wt% of a thiol-acrylic resin and 5 to 20 wt% of an epoxy resin. The thiol-acrylic resin is a resin formed by copolymerization of a thiol compound and an acrylate monomer. It has a large number of polar groups, strong metal affinity, and high metal adhesion, so that the carbon fiber and nano-inorganic material are first dispersed in the sizing agent solution; the epoxy resin is a class of organic polymer compounds containing two or more epoxy groups, and these epoxy groups can be located at the end, middle or in a ring structure of the molecular chain, so that the epoxy resin has good adhesion and bonding ability, and can better bond the carbon fiber and nano-inorganic metal material under the synergistic effect of the thiol-acrylic resin, and then bond the thermotropic liquid crystal and thermoplastic resin, thereby improving the bonding strength of each component.

[0025] More preferably, the weight fraction of the thiol-acrylic resin is 25-35 wt%, such as 25 wt%, 30 wt%, or 35 wt%, so as to improve the bonding strength with the metal.

[0026] More preferably, the weight fraction of the epoxy resin is 10-15wt%, such as 10wt%, 15wt%. If the weight fraction of the epoxy resin is smaller, the bonding strength is lower. If it is larger, the bonding and curing at high temperature may cause printing difficulties.

[0027] More preferably, the solvent in the sizing agent is C1-C12 monoalcohol or C1-C12 diol.

[0028] More preferably, the sizing agent solution includes one or more of ethylene glycol and butanediol aqueous solutions, which improves the ease of filtering and separating the carbon fiber metal material from the solution and the adhesion of the material.

[0029] Still further preferably, the concentration of the ethylene glycol and butanediol is 40% to 60%, preferably the weight percentage concentration of ethylene glycol and butanediol is 50%, that is, the weight ratio of the ethylene glycol, butanediol and water is 1:1, so as to improve the sizing rate and the simplicity of filtration.

[0030] Preferably, in the above technical solution, the modified carbon fiber accounts for 45 to 70 parts by weight, such as 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, or 70 parts.

[0031] Preferably, in the above technical solution, the weight ratio of the carbon fiber metal material to the thermotropic liquid crystal is 1:0.65 to 0.8, such as 1:0.7, 1:0.8, etc. If the content of the thermotropic liquid crystal is reduced, the fluidity of the material is low during high-temperature melting printing, resulting in printing difficulties. If the content of the thermotropic liquid crystal is high, it is easy to cause the material fluidity to be large during printing, resulting in disconnection.

[0032] In the above technical solution, preferably, the thermoplastic resin is selected from one or more of polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamide, polyoxymethylene, polycarbonate, polyphenylene ether, polysulfone, and polyester.

[0033] Further preferably, the thermoplastic resin is selected from one or more of polyamide and polycarbonate to obtain better thermal stability and adhesion between the thermoplastic resin and the modified carbon fiber.

[0034] More preferably, the polyamide is a polymer material containing an amide group (-CO-NH-) repeating structural unit, which can be an aliphatic polyamide, including polybutylene adipamide, polyhexamethylene adipamide, polyhexamethylene sebacamide, polyhexamethylene dodecane diamide, and polydecamethylene sebacamide; semi-aromatic polyamides: polybutylene terephthalamide, polybutylene furan diamide, polypentamethylene terephthalamide, polypentamethylene furan diamide, polyhexamethylene terephthalamide, polyhexamethylene furan diamide, polynonamethylene terephthalamide, polyfuran diamide, polybutylene terephthal ...butylene terephthalamide, polypentamethylene furan diamide, polyhexamethylene terephthalamide, polyhexamethylene furan diamide, polyhexamethylene terephthalamide, polyhexamethylene furan diamine, polyhexamethylene terephthalamide, polyhexamethylene furan diamine, polyhexamethylene furan diamine, polyhexamethylene furan diamine, polyhexamethylene furan diamine, polyhexamethylene furan diamine, polyhexamethylene furan diamine, polyhexamethylene furan diamine, polyhexamethylene furan diamine, polyhexamethylene furan diamine, polyhexamethylene furan diamine, polyhexamethylene furan diamine, polyhexamethylene furan diamine, polyhexamethylene furan Nonanediamine, poly(decane terephthalamide), poly(decane furan diamine), poly(dodecanediamine terephthalamide), poly(dodecanediamine furan diamine), poly(tridecanediamine terephthalamide), poly(tridecanediamine furan diamine), poly(hexamethylene terephthalamide adipate decanediamine), poly(furan dicarboxamide terephthalate decanediamine), poly(pentamethylene terephthalate furan dicarboxamide), poly(furan dicarboxamide terephthalate decanediamine); aromatic polyamides: poly(p-phenylene terephthalamide), poly(furan diamine), poly(p-phenylene terephthalamide furan diamine). Considering the convenience of 3D printing, poly(hexamethylene adipamide) is preferred.

[0035] More preferably, the polycarbonate is a polymer material whose main molecular chain contains -O-(C=O)-O- groups in its chemical structure. It can be an aliphatic polycarbonate, including polyethylene carbonate, polytrimethylene carbonate, and copolymers thereof; or an aromatic polycarbonate, including bisphenol A polycarbonate. For better mechanical properties, bisphenol A polycarbonate is preferred among aromatic polycarbonates.

[0036] Preferably, in the above technical solution, the thermoplastic elastomer resin is selected from polyurethane thermoplastic elastomer resin, polyester thermoplastic elastomer resin, polyamide thermoplastic elastomer resin, and polyolefin thermoplastic elastomer resin.

[0037] More preferably, the thermoplastic elastomer resin is a polyolefin thermoplastic elastomer resin.

[0038] More preferably, the polyolefin thermoplastic elastomer resin may be an ethylene-α-olefin copolymer, a propylene-α-olefin copolymer, a blend of EPDM and polypropylene, or an ethylene-tetrafluoroethylene copolymer. Considering the adhesion between the thermoplastic elastomer resin and the nano-inorganic material, an organic fluorine-based polyolefin thermoplastic elastomer, an ethylene-tetrafluoroethylene copolymer, is preferred.

[0039] Preferably, in the above technical solution, the thermoplastic elastomer resin is 7 to 13 parts by weight, such as 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, etc.

[0040] In the above technical solution, the thermotropic liquid crystal is preferably a thermotropic liquid crystal polyarylate, which is a type of high molecular weight polymer composed of aromatic monomers. Its molecular chain has high regularity and can transform from a solid state (crystalline or glassy state) to a liquid crystal state at a certain temperature during heating. Its molecules are composed of rigid rod-shaped macromolecular chains. After melting under heat, it forms a liquid crystal state that combines the properties of both solid and liquid. It has the advantages of high strength, high modulus, high chemical resistance, and good dimensional stability. At high temperatures, it is in an ultra-high fluidity state and remains in a liquid crystal phase during the melt processing process. At high temperatures, it becomes liquid and can be converted to a liquid state during hot rolling and infrared heat treatment, thereby increasing the material's fluidity, avoiding the discontinuity of the material during 3D printing, and reducing the generation of bubbles during the printing process that affect the material's mechanical strength.

[0041] Preferably, the melting point of the thermotropic liquid crystal is 250-320°C. The melting point is tested by differential scanning calorimetry (DSC). 3-8 mg of the sample is weighed. In a nitrogen atmosphere, the air flow rate is 50 mL / min. The sample is heated to 350°C using a programmed temperature increase method (10°C / min). The peak value of the melting peak in the spectrum is read as the melting point.

[0042] Further preferably, the melting point of the thermotropic liquid crystal is 250-300° C., so as to improve the fluidity of the printing material at high temperature and the required heating temperature.

[0043] Another object of the present invention is to provide a carbon fiber 3D printing material, particularly a carbon fiber 3D printing material with good fluidity and superior mechanical properties.

[0044] In order to achieve the above object, the technical solution adopted by the present invention is:

[0045] A carbon fiber 3D printing material, comprising the following components:

[0046] 100 parts by weight of polyhexamethylene adipamide;

[0047] 7-13 parts by weight of ethylene-tetrafluoroethylene copolymer;

[0048] 45-70 parts by weight of modified carbon fiber;

[0049] Wherein: the modified carbon fiber comprises carbon fiber metal material and thermotropic liquid crystal polyarylate, the weight ratio of the carbon fiber metal material and thermotropic liquid crystal polyarylate is 1:0.65-0.80, and the melting point of the thermotropic liquid crystal polyarylate is 250-300°C.

[0050] The carbon fiber metal material includes carbon fiber powder, titanium nitride, and a sizing agent. The weight ratio of the carbon fiber powder to titanium nitride is 1:0.8-1.5. The solution of the sizing agent includes 25-35wt% of a thiol-acrylic resin, and the solution of the sizing agent includes ethylene glycol.

[0051] Another object of the present invention is to provide a method for preparing carbon fiber 3D printing materials.

[0052] In order to achieve the above object, the technical solution adopted by the present invention is:

[0053] A method for preparing carbon fiber 3D printing material comprises the following steps in sequence:

[0054] S1: Preparation of modified carbon fibers:

[0055] (1) Weighing a certain amount of carbon fiber and nano inorganic material, dispersing them in a sizing agent solution, mixing them, and filtering to obtain a carbon fiber metal material;

[0056] (2) Weigh a certain amount of carbon fiber metal material and thermotropic liquid crystal, mix them, perform hot pressing and heat treatment, and then crush and screen them to obtain modified carbon fiber.

[0057] S2: Weigh a certain amount of thermoplastic resin, thermoplastic elastomer resin, and modified carbon fiber, mix them, heat them until they are melted, extrude them, cool them, and then crush and screen them to obtain carbon fiber 3D printing materials.

[0058] Preferably, in the above technical solution, the carbon fiber is selected from carbon fiber powder, chopped carbon fiber, and chopped carbon fiber.

[0059] Further preferably, the carbon fiber is carbon fiber powder to obtain better sizing properties, thermal conductivity and simplicity of preparation process.

[0060] Preferably, in the above technical solution, the average particle size of the carbon fibers is 1 to 200 μm.

[0061] In the above technical solution, preferably, the average particle size of the nano-inorganic material is 10 to 100 nm, thereby improving the uniform dispersion between the nano-inorganic material and the components.

[0062] Preferably, in the above technical solution, in S1(1): ultrasonic mixing is performed for 10 to 60 minutes.

[0063] Preferably, in the above technical solution, in S1(2): a high-speed ball mill is used for uniform mixing.

[0064] Preferably, in the above technical solution, the average particle size of the modified carbon fiber is 1 to 200 μm.

[0065] The above technical solution preferably adopts hot roller pressing and infrared heat treatment to mix carbon fiber metal material and thermotropic liquid crystal, which are squeezed, sheared and kneaded by hot rollers, fully impregnated and mixed, and then subjected to infrared heat treatment process for rapid heat transfer and in-situ adsorption and bonding, thereby shortening the preparation time and making the components in the modified carbon fiber evenly mixed.

[0066] In the above technical solution, the hot pressing temperature is preferably 180-230°C, and the heat treatment temperature is 240-300°C, so as to improve the material strength and shorten the preparation time.

[0067] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0068] 1. The 3D printing material of the present invention is initially toughened by thermotropic liquid crystal grafted carbon fibers, and then further toughened with thermoplastic elastomer to provide material toughness;

[0069] 2. The 3D printing material of the present invention improves the bonding strength between carbon fiber and metal by modifying epoxy resin with thiol-acrylic acid and introducing a large number of polar groups by graft bonding. In addition, the organic fluorine-based polyolefin thermoplastic elastomer has low electronegativity, strong affinity for carbon fiber and metal, and good bonding force, which effectively avoids the phenomenon of material disconnection during printing. The printed material has excellent mechanical properties.

[0070] 3. The 3D printing material of the present invention uses sizing-treated carbon fibers and is combined with thermotropic liquid crystals, which are sequentially subjected to hot pressing and external heat treatment. During this process, the sizing agent on the surface of the carbon fibers is desolvated and gradually solidified and cross-linked, forming physical entanglement and chemical bonding with the thermotropic liquid crystals, thereby forming an optimal interface bond.

[0071] 4. The 3D printing material of the present invention is prepared using materials such as thermotropic liquid crystal and thiol-acrylic acid. It has better processing fluidity at high temperatures, improves the high-temperature fluidity of thermoplastic resins, and facilitates 3D printing.

[0072] 5. The 3D printing material of the present invention has metal and carbon fiber added, which makes the heat transfer fast during hot pressing and heat treatment, and has better energy saving performance. DETAILED DESCRIPTION

[0073] The following is a clear and complete description of the technical solution of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0074] The raw materials used in each embodiment and comparative example are as follows:

[0075]

Thermoplastic resin

[0076] A1: Polyhexamethylene adipamide, P137N polyhexamethylene adipamide produced by Liaoning Xingjia.

[0077] A2: Polycarbonate, Covestro's 2805 polycarbonate.

[0078]

Polyolefin thermoplastic elastomer resin

[0079] B1: Ethylene-tetrafluoroethylene copolymer, ET815M ethylene-tetrafluoroethylene copolymer produced by Shandong Dongyue Group.

[0080] B2: Polyethylene elastomer, produced by Dow Chemical ENGAGE TM 8137 TPO polyethylene elastomer.

[0081]

Carbon fiber

[0082] C1: carbon fiber powder, MLD-300 carbon fiber powder produced by Toray Industries, Ltd. of Japan, with a fiber length of 130 μm.

[0083] C2: Chopped carbon fiber, T700 chopped carbon fiber produced by Toray Industries, Ltd. of Japan, fiber length 2mm.

[0084]

Inorganic nanomaterials

[0085] D1: Titanium carbide, CW-TiC-001 nano-titanium carbide powder produced by Shanghai Chaowei Nanotechnology Co., Ltd., with an average particle size of 50nm.

[0086] D2: Titanium nitride, CW-TiN-001 nano titanium nitride powder produced by Shanghai Chaowei Nanotechnology Co., Ltd., with an average particle size of 20nm.

[0087]

Thermotropic LCD

[0088] F: Thermotropic liquid crystal polyarylate, Vectra A950 thermotropic liquid crystal produced by Celanese Corporation, with a melting point of 280℃.

[0089]

acrylic acid

[0090] G1: Mercaptan-acrylic acid, SW917 mercaptan-acrylic acid resin produced by Guangzhou Sanwang Chemical Materials Co., Ltd.

[0091] G2: Polyurethane acrylate, SW2300 aliphatic polyurethane acrylate produced by Guangzhou Sanwang Chemical Materials Co., Ltd.

[0092] Epoxy resin

[0093] H: Epoxy resin, epoxy resin, Mitsubishi Chemical produced YX4000H biphenyl type epoxy resin.

[0094] Solvent

[0095] M1: Ethylene glycol, produced by Sinopharm Chemical Reagent Co., Ltd. 10009818 ethylene glycol.

[0096] M2: Butanediol, Sinopharm Chemical Reagent Co., Ltd., product number 30029118. M3: Deionized water.

[0097] Table 1:

[0098]

[0099]

Modified carbon fiber

[0100] Modified carbon fiber (Q1-Q13, Q18-Q22) is weighed and configured with a sizing agent solvent according to the formula shown in Table 1, and then acrylic acid and epoxy resin are added according to the formula amount, and mixed evenly to obtain a sizing agent solution. Carbon fiber and nano-inorganic material are quantitatively weighed according to the formula amount, dispersed in the sizing agent solution, ultrasonically mixed for 40 minutes, and filtered to obtain a carbon fiber metal material. Carbon fiber metal material is quantitatively weighed, thermotropic liquid crystal powder is added according to the proportion shown in Table 1, placed in a high-speed ball mill and mixed evenly, and then subjected to hot rolling and infrared heat treatment. The hot rolling temperature is 200 degrees Celsius and the residence time is 30 minutes. The infrared heat treatment temperature is 285 degrees Celsius and the residence time is 5 minutes. After cooling, it is crushed and sieved to 150μm.

[0101] The modified carbon fiber (Q14) is weighed and configured with a sizing agent solvent according to the formula shown in Table 1, and then acrylic acid and epoxy resin are added according to the formula amount, and mixed evenly to obtain a sizing agent solution. Carbon fiber and nano-inorganic material are quantitatively weighed according to the formula amount, dispersed in the sizing agent solution, ultrasonically mixed for 40 minutes, and filtered to obtain a carbon fiber metal material. Carbon fiber metal material is quantitatively weighed, thermotropic liquid crystal powder is added according to the proportion shown in Table 1, placed in a high-speed ball mill and mixed evenly, and then subjected to hot rolling and infrared heat treatment. The hot rolling temperature is 180 degrees Celsius and the residence time is 30 minutes. The infrared heat treatment temperature is 285°C and the residence time is 5 minutes. After cooling, it is crushed and sieved to 150μm.

[0102] The modified carbon fiber (Q15) is weighed and configured with a sizing agent solvent according to the formula shown in Table 1, and then acrylic acid and epoxy resin are added according to the formula amount, and mixed evenly to obtain a sizing agent solution. Carbon fiber and nano-inorganic material are quantitatively weighed according to the formula amount, dispersed in the sizing agent solution, ultrasonically mixed for 40 minutes, and filtered to obtain a carbon fiber metal material. Carbon fiber metal material is quantitatively weighed, thermotropic liquid crystal powder is added according to the proportion shown in Table 1, placed in a high-speed ball mill and mixed evenly, and then subjected to hot rolling and infrared heat treatment. The hot rolling temperature is 180 degrees Celsius and the residence time is 30 minutes. The infrared heat treatment temperature is 285°C and the residence time is 5 minutes. After cooling, it is crushed and sieved to 150μm.

[0103] The modified carbon fiber (Q16) is weighed and configured with a sizing agent solvent according to the formula shown in Table 1, and then acrylic acid and epoxy resin are added according to the formula amount, and mixed evenly to obtain a sizing agent solution. Carbon fiber and nano-inorganic material are quantitatively weighed according to the formula amount, dispersed in the sizing agent solution, ultrasonically mixed for 40 minutes, and filtered to obtain a carbon fiber metal material. Carbon fiber metal material is quantitatively weighed, thermotropic liquid crystal powder is added according to the proportion shown in Table 1, placed in a high-speed ball mill and mixed evenly, and then subjected to hot rolling and infrared heat treatment. The hot rolling temperature is 200 degrees Celsius and the residence time is 30 minutes. The infrared heat treatment temperature is 240°C and the residence time is 5 minutes. After cooling, it is crushed and sieved to 150μm.

[0104] The modified carbon fiber (Q17) was weighed and configured with a sizing agent solvent according to the formula shown in Table 1, and then acrylic acid and epoxy resin were added according to the formula amount, and mixed evenly to obtain a sizing agent solution. Carbon fiber and nano-inorganic material were quantitatively weighed according to the formula amount, dispersed in the sizing agent solution, ultrasonically mixed for 40 minutes, and filtered to obtain a carbon fiber metal material. Carbon fiber metal material was quantitatively weighed, thermotropic liquid crystal powder was added according to the proportion shown in Table 1, placed in a high-speed ball mill and mixed evenly, and then subjected to hot rolling and infrared heat treatment. The hot rolling temperature was 200 degrees Celsius and the residence time was 30 minutes. The infrared heat treatment temperature was 300°C and the residence time was 5 minutes. After cooling, it was crushed and sieved to 150μm.

[0105] The modified carbon fiber (Q23) was weighed and prepared with a sizing agent solvent according to the formula shown in Table 1, and then acrylic acid and epoxy resin were added according to the formula amount, and mixed evenly to obtain a sizing agent solution. Carbon fiber and nano-inorganic material were quantitatively weighed according to the formula amount, dispersed in the sizing agent solution, ultrasonically mixed for 40 minutes, and filtered to obtain a carbon fiber metal material. Carbon fiber metal material was quantitatively weighed, and thermotropic liquid crystal powder was added according to the proportion shown in Table 1. The mixture was placed in a high-speed ball mill and mixed evenly. It was then subjected to infrared heat treatment at a temperature of 300°C and a residence time of 5 minutes. After cooling, it was crushed and sieved to 150μm.

[0106] The modified carbon fiber (Q24) was weighed and prepared with a sizing agent solvent according to the formula shown in Table 1, and then acrylic acid and epoxy resin were added according to the formula amount, and mixed evenly to obtain a sizing agent solution. Carbon fiber and nano-inorganic material were quantitatively weighed according to the formula amount, dispersed in the sizing agent solution, ultrasonically mixed for 40 minutes, and filtered to obtain a carbon fiber metal material. Carbon fiber metal material was quantitatively weighed, and thermotropic liquid crystal powder was added according to the proportion shown in Table 1. The mixture was placed in a high-speed ball mill and mixed evenly, and then hot rolled at a temperature of 200°C and a residence time of 30 minutes. After cooling, the mixture was crushed and sieved to 150μm.

[0107] Table 2:

[0108]

[0109]

[0110] According to the formula shown in Table 2, thermoplastic resin, thermoplastic elastomer resin, and modified carbon fiber were weighed according to the formula amount, mixed evenly in a high-speed ball mill, heated to 285°C and stirred for 1 h, extruded, cooled, and then crushed and sieved to obtain 3D printing materials.

[0111] 3D printing materials were printed at a nozzle temperature of 285°C, a base plate temperature of 80°C, a printing speed of 50 mm / s, and a sample size of 80 mm × 10 mm × 4 mm. The following tests were performed on the sample. Unless otherwise specified, all tests were performed at 25°C. The main indicators are as follows:

[0112] Tensile strength: The test was conducted in accordance with GB / T1040.1-2018, and the specimen was stretched at a rate of 5 mm / min.

[0113] Charpy notched impact strength: tested in accordance with ISO179, specimen size is 80mm×10mm×4mm, notch type is A-notch.

[0114] Print test sample appearance: Select a ruler and gently place it on the surface of the 80mm×40mm sample. If the test gap after lamination is 0-0.1mm, the sample is not warped, marked as A; if the test gap is 0.1-1mm, the sample is slightly warped, marked as B; if the test gap is greater than 1mm, the sample is warped, marked as C.

[0115] Table 3:

[0116]

[0117]

[0118] As shown in Table 3, compared with the comparative example, the surface warpage of the sample printed by the 3D printing material prepared in the embodiment is small, and all reach at least B, and the tensile strength is greater than 60Mpa, and the impact strength is greater than 30kJ / m 2 , the mechanical properties of the sample are better.

[0119] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A carbon fiber 3D printing material, characterized by: Includes the following components: 100 parts by weight of thermoplastic resin; 5 to 15 parts by weight of thermoplastic elastomer resin; 40 to 80 parts by weight of modified carbon fiber, Wherein: the modified carbon fiber comprises carbon fiber metal material and thermotropic liquid crystal, and the weight ratio of the carbon fiber metal material to the thermotropic liquid crystal is 1:0.6-0.

95.

2. The carbon fiber 3D printing material according to claim 1, characterized in that: The carbon fiber composite material comprises carbon fiber, nano inorganic material and sizing agent, and the weight ratio of the carbon fiber to the nano inorganic material is 1:0.5-2.

3. The carbon fiber 3D printing material according to claim 2, characterized in that: The nano inorganic material is selected from nano metal elements, nano metal oxides, nano metal carbides, nano metal silicides, nano metal borides and nano metal nitrides.

4. The carbon fiber 3D printing material according to claim 2, characterized in that: The sizing agent solution includes one or more of 20-40 wt% of mercaptan-acrylic resin and 5-20 wt% of epoxy resin; The sizing agent solution includes one or more of ethylene glycol and butanediol aqueous solutions, and the weight percentage concentration of the ethylene glycol and butanediol is 40% to 60%.

5. The carbon fiber 3D printing material according to claim 1, characterized in that: The thermoplastic resin is selected from one or more of polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamide, polyoxymethylene, polycarbonate, polyphenylene ether, polysulfone and polyester.

6. The carbon fiber 3D printing material according to claim 1, characterized in that: The thermoplastic elastomer resin is selected from polyurethane thermoplastic elastomer resin, polyester thermoplastic elastomer resin, polyamide thermoplastic elastomer resin, and polyolefin thermoplastic elastomer resin.

7. The carbon fiber 3D printing material according to claim 1, characterized in that: The thermotropic liquid crystal is a thermotropic liquid crystal polyarylate with a melting point of 250-320°C.

8. The carbon fiber 3D printing material according to claim 1, characterized in that: The materials include: 100 parts by weight of polyhexamethylene adipamide; 7-13 parts by weight of ethylene-tetrafluoroethylene copolymer; 45-70 parts by weight of modified carbon fiber; Wherein: the modified carbon fiber comprises carbon fiber metal material and thermotropic liquid crystal polyarylate, the weight ratio of the carbon fiber metal material and thermotropic liquid crystal polyarylate is 1:0.65-0.80, and the melting point of the thermotropic liquid crystal polyarylate is 250-300°C. The carbon fiber metal material includes carbon fiber powder, titanium nitride, and a sizing agent. The weight ratio of the carbon fiber powder to titanium nitride is 1:0.8-1.

5. The solution of the sizing agent includes 25-35wt% of a thiol-acrylic resin, and the solution of the sizing agent includes ethylene glycol.

9. A method for preparing the carbon fiber 3D printing material according to any one of claims 1 to 8, characterized in that: The following steps are included in sequence: S1: Preparation of modified carbon fibers: (1) Weighing a certain amount of carbon fiber and nano inorganic material, dispersing them in a sizing agent solution, mixing them, and filtering to obtain a carbon fiber metal material; (2) Weigh a certain amount of carbon fiber metal material and thermotropic liquid crystal, mix them, perform hot pressing and heat treatment, and then crush and screen them to obtain modified carbon fiber. S2: Weigh a certain amount of thermoplastic resin, thermoplastic elastomer resin, and modified carbon fiber, mix them, heat them until they are melted, extrude them, cool them, and then crush and screen them to obtain carbon fiber 3D printing materials.

10. The method according to claim 9, characterized in that: The average particle size of the carbon fiber is 1 to 200 μm, the average particle size of the nano inorganic material is 10 to 100 nm, and the average particle size of the modified carbon fiber is 1 to 200 μm; The hot pressing temperature is 180-230°C, and the heat treatment temperature is 240-300°C.

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