Composite resin material for 3D printing and preparation method thereof

Abstract

The invention relates to a composite resin material for 3D printing and a preparation method thereof. The material is prepared from the following raw materials in parts by weight: 60-90 parts of polylactic acid, 5-15 parts of a toughening agent, 5-15 parts of a flame retardant, 5-10 parts of modified carbon nanotubes, 0.3-1 part of an anti-hydrolysis agent and 0.3-0.5 part of a lubricant. The flame retardant is added, a phosphate structure, a benzene ring and a hindered phenol structure are introduced into 5, 5 '-dibromo-[2, 2'-bipyridyl]-3, 3 '-diamine, and efficient flame retardance is achieved and the anti-aging performance of the composite resin material is enhanced through multiple synergistic effects of hindered phenol-phosphorus heterocycle-bipyridyl. The modified carbon nanotube is added as a reinforcing agent, so that the mechanical property of the composite resin material is remarkably improved, and the composite resin material is endowed with antibacterial property.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a composite resin material for 3D printing and a preparation method thereof. BACKGROUND

[0002] 3D printing is a technology that uses powder-like metal or plastic and other materials that can be bonded to construct objects through layer-by-layer stacking. Compared with traditional injection molding, molding and other processes, this technology has the advantages of fast molding speed, high precision and high material utilization, and has received widespread attention in recent years. The mainstream 3D printing technologies currently include stereolithography (SLA), layer manufacturing (LOM), selective laser sintering (SLS) and fused deposition modeling (FDM).

[0003] In the research of FDM 3D printing technology, the commonly used materials cover a variety of polymers and their composites, among which polylactic acid (PLA) is the most widely used. PLA is a biodegradable polymer material that not only has good biocompatibility and excellent mechanical properties, but also has the advantages of low elongation at break, small thermal expansion coefficient and easy processing into a shape. Therefore, PLA is considered to be an ideal material for FDM 3D printing. However, PLA also has some shortcomings, such as low impact strength, high brittleness, poor aging resistance, flammability, and is more susceptible to bacterial and fungal erosion due to its biodegradable properties. Therefore, it is particularly important to modify PLA to address these issues. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, one of the purposes of the present application is to provide a composite resin material for 3D printing.

[0005] The second purpose of the present application is to provide a preparation method of a composite resin material for 3D printing.

[0006] In order to achieve the above-mentioned purposes of the application, the technical scheme adopted by the present application is as follows:

[0007] The present application provides a composite resin material for 3D printing, wherein the raw material composition of the composite resin material for 3D printing comprises, by weight fraction: polylactic acid 60-90 parts, toughening agent 5-15 parts, flame retardant 5-15 parts, modified carbon nanotube 5-10 parts, anti-hydrolysis agent 0.3-1 parts, and lubricant 0.3-0.5 parts.

[0008] Preferably, the chemical structural formula of the flame retardant is

[0009] Preferably, the preparation process of the flame retardant is as follows:

[0010] (1-1) Under nitrogen protection, 5,5'-dibromo-[2,2'-bipyridine]-3,3'-diamine and triethylamine are added into dichloromethane A and dissolved thoroughly, then 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphorinane-2-oxide is added dropwise into dichloromethane B at 0℃, after reaction, intermediate 1 is obtained by vacuum distillation, washing and drying;

[0011] (1-2) Under nitrogen protection, intermediate 1, tert-butyl hydroquinone and potassium carbonate are dissolved in N,N-dimethylformamide, after reaction, the product is obtained by vacuum distillation, washing and drying.

[0012] Preferably, in the step (1-1), the amount ratio of 5,5'-dibromo-[2,2'-bipyridine]-3,3'-diamine, 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphorinane-2-oxide, triethylamine and dichloromethane A is 0.05 mol:0.1-0.12 mol:0.1-0.12 mol:200-250 mL; the concentration of 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphorinane-2-oxide in dichloromethane B is 1.5-2 mol / L; the reaction temperature is 25-30℃ and the reaction time is 10-15 h.

[0013] Preferably, in the step (1-2), the amount ratio of intermediate 1, tert-butyl hydroquinone, potassium carbonate and N,N-dimethylformamide is 2 mmol:4-4.5 mmol:5-6 mmol:25-30 mL; the reaction condition is that the reaction is carried out at room temperature for 12-18 h.

[0014] In the present application, a flame retardant is added to the composite resin material for 3D printing, and the flame retardant performance and anti-aging ability of the composite resin material are improved. The flame retardant principle is that the phosphoric acid ester structure is decomposed under heat to not only catalyze the formation of a dense carbon layer on the surface of the material, but also release phosphorus-containing free radicals (PO·, etc.) to quench active free radicals (H· / OH·) in the fire source; the benzene ring as a carbon-rich unit cooperates with the phosphoric acid ester to promote the formation of a graphitized carbon layer, further improving the density and thermal stability of the carbon layer; nitrogen gas released by the decomposition of the bipyridine skeleton dilutes the concentration of combustible gas, and this multi-element synergistic system of phosphorus-nitrogen-aromatic ring blocks the combustion chain reaction through the dual flame retardant mechanism of condensed phase and gas phase, achieving high-efficiency flame retardation.

[0015] Anti-aging performance: hindered phenol structure inhibits material oxidative degradation by efficiently capturing free radicals; bipyridine conjugated rigid skeleton not only absorbs ultraviolet light, but also reduces structural dissociation at high temperature by inhibiting molecular thermal motion, while stabilizing free radical intermediates, and synergistically enhances molecular thermal stability with phosphorus heterocyclic structure; phosphorus heterocycle can further inhibit the oxidation process by decomposing peroxide. The multiple synergistic effects of hindered phenol-phosphorus heterocycle-bipyridine not only provide immediate free radical capture ability, but also enhance the persistence of anti-aging effect through phosphorus-nitrogen synergistic effect, significantly enhancing the anti-aging performance of the material.

[0016] Preferably, the preparation process of the modified carbon nanotube is as follows:

[0017] (2-1) ultrasonic dispersion of amino carbon nanotubes in N,N-dimethylformamide, addition of 2-(methyl-prop-2-ylamino) acetic acid, 1,4-dioxane and p-toluenesulfonic acid, after reaction, filtration, washing, drying, to obtain intermediate 2;

[0018] (2-2) under nitrogen protection, ultrasonic dispersion of intermediate 2 in N,N-dimethylformamide, addition of chloropropyl triethoxysilane and potassium iodide, after reaction, filtration, washing, drying, to obtain.

[0019] Preferably, in step (2-1), the amount ratio of amino carbon nanotubes, 2-(methyl-prop-2-ylamino) acetic acid, p-toluenesulfonic acid, N,N-dimethylformamide and 1,4-dioxane is 1g:2-4g:0.05-0.2g:40-50mL:15-30mL; the reaction temperature is 90-100℃, and the reaction time is 24-48h.

[0020] Preferably, in step (2-2), the amount ratio of intermediate 2, chloropropyl triethoxysilane, potassium iodide and N,N-dimethylformamide is 0.5g:1.8-3.6g:0.05-0.2g:40-65mL; the reaction temperature is 150-160℃, and the reaction time is 15-20h.

[0021] Preferably, the melt index of the polylactic acid is 5-25g / 10min at 190℃ under a load of 2.16kg; the toughening agent is polybutylene succinate; the anti-hydrolysis agent is monomeric carbodiimide; and the lubricant is at least one of ethylene bis-stearamide, pentaerythritol stearate and oleic acid amide.

[0022] The application provides a preparation method of the composite resin material for 3D printing, which comprises the following steps: uniformly mixing polylactic acid, a toughening agent, a flame retardant, modified carbon nanotubes, an anti-hydrolysis agent and a lubricant, melt extruding and granulating, and then obtaining the composite resin material.

[0023] Preferably, the melt extrusion temperature is 150-200℃.

[0024] Compared with the prior art, the application has the beneficial effects that:

[0025] The application provides a polylactic acid-based composite resin material for 3D printing, wherein modified carbon nanotubes are added as reinforcing agents, so that the mechanical properties of the composite resin material are significantly improved and the composite resin material is endowed with antibacterial properties.

[0026] The application adds a flame retardant in the polylactic acid-based composite resin material for 3D printing, so that the flame retardant properties of the composite resin material are significantly improved, and the anti-aging ability of the composite resin material is effectively enhanced.

[0027] The application provides a preparation method of a composite resin material for 3D printing, and the preparation process is simple and suitable for industrial production and application. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The infrared spectra of the modified carbon nanotubes and the amino carbon nanotubes in Example 1 of the application. DETAILED DESCRIPTION

[0029] The application will be further described below in combination with the drawings and specific embodiments, and it should be noted that, under the premise of no conflict, each embodiment described below or each technical feature can be combined to form a new embodiment. The specific conditions not mentioned in the embodiments are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used, if not specially mentioned, are conventional products obtained through market channels.

[0030] Example 1

[0031] The present example provides a composite resin material for 3D printing, the raw material composition of which includes, by weight fraction: polylactic acid (NatureWorks 3001D, melt index of 20 g / 10 min at 190°C, 2.16 kg) 75 parts, toughening agent (polybutylene succinate, Showa Denko 3001MD) 10 parts, flame retardant 10 parts, modified carbon nanotube 8 parts, hydrolysis-resistant agent (monomeric carbodiimide, HyMax 1010) 0.6 parts, lubricant (oleic acid amide) 0.4 parts.

[0032] The preparation process of the flame retardant in the present example is as follows:

[0033]

[0034] (1-1) Under nitrogen protection, 5,5'-dibromo-[2,2'-bipyridine]-3,3'-diamine and triethylamine were added to dichloromethane A and dissolved thoroughly, then 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphacyclohexylidene phosphate dichloromethane B was added dropwise at 0°C, wherein the amount ratio of 5,5'-dibromo-[2,2'-bipyridine]-3,3'-diamine, 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphacyclohexylidene phosphate, triethylamine and dichloromethane A was 0.05 mol:0.11 mol:0.11 mol:230 mL; the concentration of 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphacyclohexylidene phosphate in dichloromethane B was 1.8 mol / L; then after reaction at 30°C for 12 h, the solvent was removed by vacuum distillation, and then washed with distilled water, toluene and anhydrous ethanol in sequence, and vacuum dried to obtain intermediate 1 (yield 88.6%); the intermediate 1 obtained was characterized by HNMR and MS as follows: 1 HNMR: (C 20 H 26 N4O6P2Br2, 400 MHz, DMSO-d6) δ: 0.89 (s, 12H), 3.88-3.90 (d, 8H), 5.45 (s, 2H), 7.60 (s, 2H), 8.16 (s, 2H). MS (ESI) m / z = 639.97 [M].

[0035] (1-2) Under the protection of nitrogen, intermediate 1, tert-butyl hydroquinone and potassium carbonate were dissolved in N,N-dimethylformamide, wherein the amount ratio of intermediate 1, tert-butyl hydroquinone, potassium carbonate, N,N-dimethylformamide was 2 mmol: 4.2 mmol: 5.5 mmol: 28 mL; after reaction at room temperature for 16 h, the reaction was quenched with 6 mol / L hydrochloric acid, and the filtrate was obtained by filtration, the pH of the filtrate was adjusted to neutral, the solvent was removed by vacuum distillation, and the product was washed with distilled water and ethyl acetate, and dried in vacuum to obtain the flame retardant (yield 83.6%). The obtained flame retardant had the following properties: 1 HNMR: (C 40 H 52 N4O 10 P2, 400 MHz, DMSO-d6) δ: 0.89 (s, 12H), 1.40 (s, 18H), 3.88-3.90 (d, 8H), 5.45 (s, 2H), 6.54-6.58 (d, 2H), 6.68 (s, 2H), 6.74-6.78 (d, 2H), 6.80 (s, 2H), 7.83 (s, 2H), 9.68 (s, 2H). MS (ESI) m / z = 810.32 [M].

[0036] The preparation process of the modified carbon nanotube in the embodiment is as follows:

[0037]

[0038] (2-1) Amino carbon nanotubes were ultrasonically dispersed in N,N-dimethylformamide, and 2-(methyl-prop-2-ylamino) acetic acid, 1,4-dioxane and p-toluenesulfonic acid were added, wherein the amount ratio of amino carbon nanotubes, 2-(methyl-prop-2-ylamino) acetic acid, p-toluenesulfonic acid, N,N-dimethylformamide and 1,4-dioxane was 1 g: 3 g: 0.1 g: 45 mL: 20 mL; after reaction at 100°C for 36 h, filtration, deionized water, acetone washing, vacuum drying, intermediate 2 was obtained;

[0039] (2-2) Under the protection of nitrogen, intermediate 2 was ultrasonically dispersed in N,N-dimethylformamide, and chloropropyl triethoxysilane and potassium iodide were added, wherein the amount ratio of intermediate 2, chloropropyl triethoxysilane, potassium iodide and N,N-dimethylformamide was 0.5 g: 2.7 g: 0.1 g: 55 mL; after reflux reaction at 160°C for 18 h, filtration, deionized water, acetone washing, vacuum drying, the modified carbon nanotube was obtained. The infrared spectrum of the obtained modified carbon nanotube is shown in Figure 1 It can be seen from Figure 1 that the modified carbon nanotube has 1748 cm -1 , 1176 cm -1 , 1045 cm -1The characteristic peaks of C=O, Si-O and Si-C appeared nearby, indicating that the modification of carbon nanotubes was successful.

[0040] The preparation method of the composite resin material for 3D printing in this embodiment includes the following steps: adding polylactic acid, toughening agent, flame retardant, modified carbon nanotubes, hydrolysis-resistant agent and lubricant into a high-speed blender to mix uniformly, then adding into a twin-screw extruder, melting extruding and granulating at 180℃, and then obtaining the product.

[0041] Example 2

[0042] The composite resin material for 3D printing provided in this embodiment includes, in terms of weight fraction, polylactic acid (NatureWorks 3001D) 90 parts, toughening agent (polybutylene succinate, Showa Denko 3001MD) 15 parts, flame retardant 15 parts, modified carbon nanotubes 10 parts, hydrolysis-resistant agent (monomeric carbodiimide, HyMax 1010) 1 part, and lubricant (pentaerythritol stearate) 0.5 part.

[0043] The preparation process of the flame retardant in this embodiment is as follows:

[0044] (1-1) Under the protection of nitrogen, 5,5'-dibromo-[2,2'-bipyridine]-3,3'-diamine and triethylamine were added into dichloromethane A to dissolve completely, then 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphacyclohexylidene phosphonic acid ester was added dropwise into dichloromethane B at 0℃, wherein the amount ratio of 5,5'-dibromo-[2,2'-bipyridine]-3,3'-diamine, 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphacyclohexylidene phosphonic acid, triethylamine and dichloromethane A was 0.05 mol:0.12 mol:0.12 mol:250 mL; the concentration of 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphacyclohexylidene phosphonic acid ester in dichloromethane B was 2 mol / L; then the reaction was carried out at 30℃ for 10 h, the solvent was removed by vacuum distillation, and then the product was washed with distilled water, toluene and anhydrous ethanol in sequence, and dried in vacuum to obtain intermediate 1 (yield 87.9%); the intermediate 1 obtained had the following characteristics: 1 HNMR was the same as that in Example 1.

[0045] (1-2) Under the protection of nitrogen, intermediate 1, tert-butyl hydroquinone and potassium carbonate were dissolved in N,N-dimethylformamide, wherein the amount ratio of intermediate 1, tert-butyl hydroquinone, potassium carbonate and N,N-dimethylformamide was 2 mmol:4.5 mmol:6 mmol:30 mL; the reaction was carried out at room temperature for 18 h, then the reaction was quenched with 6 mol / L hydrochloric acid, and the filtrate was obtained by filtration, then the pH of the filtrate was adjusted to neutral, the solvent was removed by vacuum distillation, and then the product was washed with distilled water and ethyl acetate, and dried in vacuum to obtain the flame retardant (yield 83.1%); the flame retardant obtained had the following characteristics:1 HNMR as Example 1.

[0046] The preparation process of the modified carbon nanotubes in this example is as follows:

[0047] (2-1) The amino carbon nanotubes were ultrasonically dispersed in N,N-dimethylformamide, and 2-(methyl-prop-2-ylamino) acetic acid, 1,4-dioxane and p-toluenesulfonic acid were added, wherein the amount ratio of the amino carbon nanotubes, 2-(methyl-prop-2-ylamino) acetic acid, p-toluenesulfonic acid, N,N-dimethylformamide and 1,4-dioxane was 1g:4g:0.2g:50mL:30mL; after reaction at 100℃ for 24h, filtration, deionized water, acetone washing, vacuum drying, the intermediate 2 was obtained;

[0048] (2-2) The intermediate 2 was ultrasonically dispersed in N,N-dimethylformamide under nitrogen protection, and chloropropyl triethoxysilane and potassium iodide were added, wherein the amount ratio of the intermediate 2, chloropropyl triethoxysilane, potassium iodide and N,N-dimethylformamide was 0.5g:3.6g:0.2g:65mL; after refluxing reaction at 160℃ for 15h, filtration, deionized water, acetone washing, vacuum drying, the modified carbon nanotubes were obtained.

[0049] The preparation method of the composite resin material for 3D printing in this example includes the following steps: the polylactic acid, toughening agent, flame retardant, modified carbon nanotubes, hydrolysis-resistant agent and lubricant are added into a high-speed blender and mixed uniformly, then added into a twin-screw extruder, melt-extruded and granulated at 200℃, and the composite resin material for 3D printing is obtained.

[0050] Example 3

[0051] The composite resin material for 3D printing provided in this example includes the following raw material components in parts by weight: polylactic acid (NatureWorks 3001D) 60 parts, toughening agent (polybutylene succinate, Showa Denko 3001MD) 5 parts, flame retardant 5 parts, modified carbon nanotubes 5 parts, hydrolysis-resistant agent (monomeric carbodiimide, HyMax 1010) 0.3 parts, and lubricant (ethylene bis-stearamide) 0.3 parts.

[0052] The preparation process of the flame retardant in this example is as follows:

[0053] (1-1) Under nitrogen protection, 5, 5'-dibromo-[2, 2'-bipyridine]-3, 3'-diamine and triethylamine were added into dichloromethane A to be fully dissolved, then 5, 5-dimethyl-2-chloro-1, 3, 2-dioxaphosphorinane-2-oxide was added dropwise into dichloromethane B at 0℃, wherein the amount ratio of 5, 5'-dibromo-[2, 2'-bipyridine]-3, 3'-diamine, 5, 5-dimethyl-2-chloro-1, 3, 2-dioxaphosphorinane-2-oxide, triethylamine and dichloromethane A was 0.05 mol: 0.1 mol: 0.1 mol: 200 mL; the concentration of 5, 5-dimethyl-2-chloro-1, 3, 2-dioxaphosphorinane-2-oxide in dichloromethane B was 1.5 mol / L; then after reaction at 25℃ for 15 h, the solvent was removed by distillation under reduced pressure, and then the product was washed with distilled water, toluene and anhydrous ethanol in sequence, and dried in vacuum to obtain intermediate 1 (yield 87.4%); the HNMR of the obtained intermediate 1 was as follows: 1 HNMR was the same as that of Example 1.

[0054] (1-2) Under nitrogen protection, intermediate 1, tert-butyl hydroquinone and potassium carbonate were dissolved in N, N-dimethylformamide, wherein the amount ratio of intermediate 1, tert-butyl hydroquinone, potassium carbonate, N, N-dimethylformamide was 2 mmol: 4 mmol: 5 mmol: 25 mL; after reaction at room temperature for 12 h, the reaction was quenched with 6 mol / L hydrochloric acid, and the filtrate was obtained by filtration, then the pH of the filtrate was adjusted to neutral, the solvent was removed by distillation under reduced pressure, and then the product was washed with distilled water and ethyl acetate, and dried in vacuum to obtain the flame retardant (yield 82.3%); the HNMR of the obtained flame retardant was as follows: 1 HNMR was the same as that of Example 1.

[0055] The preparation process of the modified carbon nanotube in the embodiment was as follows:

[0056] (2-1) Amino carbon nanotubes were ultrasonically dispersed in N, N-dimethylformamide, and 2-(methyl-prop-2-ylamino) acetic acid, 1, 4-dioxane and p-toluenesulfonic acid were added, wherein the amount ratio of amino carbon nanotubes, 2-(methyl-prop-2-ylamino) acetic acid, p-toluenesulfonic acid, N, N-dimethylformamide and 1, 4-dioxane was 1 g: 2 g: 0.05 g: 40 mL: 15 mL; after reaction at 90℃ for 48 h, the product was obtained by filtration, deionized water, acetone washing and vacuum drying; and intermediate 2 was obtained;

[0057] (2-2) Under the protection of nitrogen, the intermediate 2 was ultrasonically dispersed in N,N-dimethylformamide, and chloropropyl triethoxysilane and potassium iodide were added, wherein the ratio of the amount of intermediate 2, chloropropyl triethoxysilane, potassium iodide and N,N-dimethylformamide was 0.5 g: 1.8 g: 0.05 g: 40 mL; after refluxing at 150°C for 20h, filtering, deionized water, acetone washing, vacuum drying, the modified carbon nanotube was obtained.

[0058] The preparation method of the composite resin material for 3D printing in this embodiment includes the following steps: adding polylactic acid, toughening agent, flame retardant, modified carbon nanotube, hydrolysis resistance agent and lubricant into a high-speed blender and mixing uniformly, then adding into a twin-screw extruder, melt extruding and granulating at 150°C, and the composite resin material for 3D printing is obtained.

[0059] Comparative Example 1

[0060] The difference between this comparative example and Example 1 is that the flame retardant is replaced by direct mixing of 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphorinane-2-oxide and tert-butyl hydroquinone, and the amount of the two is the same as in Example 1.

[0061] Comparative Example 2

[0062] The difference between this comparative example and Example 1 is that the modified carbon nanotube is replaced by amino carbon nanotube.

[0063] Test Example

[0064] The composite resin materials for 3D printing obtained in Examples 1-3 and Comparative Examples 1-2 were printed into test bars by a 3D printer, and the following performances were tested respectively, and the results are shown in Table 1.

[0065] 1. The tensile strength was tested according to GB / T1040.1-2018 “Determination of tensile properties of plastics”.

[0066] 2. The notched impact strength was tested according to GB / T1843-2008 “Determination of Izod impact strength of plastics”.

[0067] 3. Aging resistance: after irradiation for 1000h under the condition of 0.55W / m 2 / nm, 340nm ultraviolet light, the tensile strength and notched impact strength were measured, and the retention rate of the tensile strength and notched impact strength after aging was calculated.

[0068] 4. The limiting oxygen index was tested according to GB / T2406.1-2008 “Determination of flammability behavior of plastics by oxygen index method”.

[0069] 5. According to GB / T 23763-2009 "Evaluation of Antibacterial Performance of Photocatalytic Antibacterial Materials and Products", Escherichia coli and Staphylococcus aureus are used as bacteria to determine the antibacterial rate.

[0070] Table 1

[0071] Group Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Tensile strength (MPa) 69.4 67.6 64.3 61.8 54.2 Notched Charpy impact strength (KJ / m 2 ) 16.7 15.3 14.8 12.5 8.6 Tensile strength after aging (MPa) 60.5 58.7 55.4 42.6 44.3 Notched Izod strength after aging (KJ / m 2 )]]> 15.8 14.2 13.7 9.4 7.3 Tensile strength retention rate (%) 87.2 86.8 86.2 68.9 81.7 Notched impact strength retention rate (%) 94.6 92.8 92.6 75.2 84.9 Limiting oxygen index (%) 33.9 33.7 33.4 22.5 30.6 Antibacterial (E. coli) rate (%) 99.3 98.6 98.4 96.7 90.5 Antibacterial (S. aureus) rate (%) 98.4 97.7 97.5 95.3 90.2

[0072] As shown in Table 1, the composite resin material for 3D printing obtained in Examples 1-3 has better mechanical properties, flame retardancy, anti-aging property and antibacterial property than Comparative Examples 1-2. Specifically, the modified carbon nanotubes added as a reinforcing agent in the present application contain quaternary ammonium salt groups and siloxane structures, which significantly improve the mechanical properties of the composite resin material and endow it with antibacterial property. The quaternary ammonium salt groups endow the material with excellent antibacterial property, and the siloxane structure not only improves the dispersibility of the carbon nanotubes in the polylactic acid matrix, but also produces a synergistic strengthening effect with the inherent high strength characteristics of the carbon nanotubes through strengthening the interfacial interaction, thereby improving the tensile strength and impact strength of the material. The flame retardant added in the present application has a phosphate structure, a benzene ring and a hindered phenol structure introduced into 5,5'-dibromo-[2,2'-bipyridine]-3,3'-diamine. On the one hand, the introduction of the phosphate structure and the benzene ring enhances the flame retardant effect; on the other hand, the introduction of the hindered phenol structure improves the anti-aging property of the material. At the same time, the nitrogen gas released by the decomposition of the bipyridine skeleton dilutes the concentration of combustible gas, and this multi-element synergistic system of phosphorus-nitrogen-aromatic ring blocks the combustion chain reaction through the dual flame retardant mechanism of condensed phase and gas phase, achieving high-efficiency flame retardation. In addition, the multiple synergistic effects of the hindered phenol-phosphorus heterocycle-bipyridine provide immediate free radical capture ability, enhance the persistence of the anti-aging effect through the phosphorus-nitrogen synergistic effect, and significantly improve the anti-aging property of the composite resin material.

[0073] The above embodiments are only preferred embodiments of the present application, and cannot be used to limit the scope of protection of the present application. Any non-essential changes and substitutions made by those skilled in the art on the basis of the present application are within the scope of the present application.

Claims

1. A composite resin material for 3D printing, characterized by, The raw material composition of the composite resin material for 3D printing comprises, by weight fraction, polylactic acid 60-90 parts, toughening agent 5-15 parts, flame retardant 5-15 parts, modified carbon nanotube 5-10 parts, hydrolysis-resistant agent 0.3-1 part, and lubricant 0.3-0.5 part.

2. The composite resin material for 3D printing according to claim 1, characterized by, The chemical structural formula of the flame retardant is 3. The composite resin material for 3D printing according to claim 2, characterized by, The preparation process of the flame retardant is as follows: (1-1) Under nitrogen protection, 5,5'-dibromo-[2,2'-bipyridine]-3,3'-diamine and triethylamine are added into dichloromethane A and dissolved thoroughly, then 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphorinane-6-oxide is added dropwise into dichloromethane B at 0℃, after reaction, the intermediate 1 is obtained by vacuum distillation, washing and drying; (1-2) Under nitrogen protection, the intermediate 1, tert-butyl hydroquinone and potassium carbonate are dissolved in N,N-dimethylformamide, after reaction, the product is obtained by vacuum distillation, washing and drying.

4. The composite resin material for 3D printing according to claim 3, characterized in that, In the step (1-1), the amount ratio of 5,5'-dibromo-[2,2'-bipyridine]-3,3'-diamine, 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphorinane-6-oxide, triethylamine and dichloromethane A is 0.05 mol:0.1-0.12 mol:0.1-0.12 mol:200-250 mL; the concentration of 5,5-dimethyl-2-chloro-1,3,2-dioxaphosphorinane-6-oxide in dichloromethane B is 1.5-2 mol / L; the reaction temperature is 25-30℃ and the reaction time is 10-15 h.

5. The composite resin material for 3D printing according to claim 3, wherein In the step (1-2), the amount ratio of the intermediate 1, tert-butyl hydroquinone, potassium carbonate and N,N-dimethylformamide is 2 mmol:4-4.5 mmol:5-6 mmol:25-30 mL; the reaction condition is that the reaction is carried out at room temperature for 12-18 h.

6. The composite resin material for 3D printing according to claim 1, wherein The preparation process of the modified carbon nanotube is as follows: (2-1) Amino carbon nanotube is ultrasonically dispersed in N,N-dimethylformamide, 2-(methyl-prop-2-ylamino) acetic acid, 1,4-dioxane and p-toluenesulfonic acid are added, after reaction, the intermediate 2 is obtained by filtration, washing and drying; (2-2) Under nitrogen protection, the intermediate 2 is ultrasonically dispersed in N,N-dimethylformamide, chloropropyltriethoxysilane and potassium iodide are added, after reaction, the product is obtained by filtration, washing and drying.

7. The composite resin material for 3D printing according to claim 6, wherein In the step (2-1), the amount ratio of amino carbon nanotube, 2-(methyl-prop-2-ylamino) acetic acid, p-toluenesulfonic acid, N,N-dimethylformamide and 1,4-dioxane is 1 g:2-4 g:0.05-0.2 g:40-50 mL:15-30 mL; the reaction temperature is 90-100℃ and the reaction time is 24-48 h.

8. The composite resin material for 3D printing according to claim 6, wherein In the step (2-2), the amount ratio of the intermediate 2, chloropropyltriethoxysilane, potassium iodide and N,N-dimethylformamide is 0.5 g:1.8-3.6 g:0.05-0.2 g:40-65 mL; the reaction temperature is 150-160℃ and the reaction time is 15-20 h.

9. The composite resin material for 3D printing according to claim 1, wherein The melt index of the polylactic acid is 5-25 g / 10 min at 190 DEG C under a load of 2.16 kg; the toughening agent is polybutylene succinate; the hydrolysis-resistant agent is a monomeric carbodiimide; and the lubricant is at least one of ethylene bis-stearamide, pentaerythritol stearate and oleic acid amide.

10. The method of claim 1-9, wherein the method is characterized by, The method comprises the following steps: uniformly mixing polylactic acid, a toughening agent, a flame retardant, modified carbon nanotubes, a hydrolysis-resistant agent and a lubricant, and then melt-extruding and granulating at 150-200 DEG C to obtain the product.

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