High-toughness high-transparency pla material and preparation method thereof, and printing consumable

Abstract

This invention discloses a high-toughness, high-transparency PLA material, its preparation method, and printing consumables. The high-toughness, high-transparency PLA material comprises a PLA matrix and modified nanoparticles dispersed in the PLA matrix. The modified nanoparticles have a core-shell structure, with the core layer comprising silicon-titanium composite nanoparticles and the shell layer comprising hyperbranched polymers coated on the surface of the core layer. Through the synergistic effect of silicon-titanium composites and hyperbranched coating, this invention enables the PLA material composed of a PLA matrix and dispersed modified nanoparticles to, under external force, utilize the silicon-titanium composite nanoparticles in the core layer as stress concentration points, effectively inducing crazes and shear yielding, significantly improving material toughness. Simultaneously, it avoids the decrease in transparency caused by particle aggregation, breaking through the bottleneck of traditional toughening methods that inevitably lead to transparency degradation, thus achieving both excellent transparency and high impact toughness.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically to a high-toughness, high-transparency PLA material, its preparation method, and printing consumables. Background Technology

[0002] Fused Deposition Modeling (FDM) 3D printing technology has become one of the most popular 3D printing technologies due to its advantages such as low equipment cost, simple operation, and wide selection of materials. Polylactic acid (PLA) is the most commonly used FDM printing material, possessing biodegradability, good printing performance, and a low melting point. However, in practical applications, pure PLA material has poor toughness, limiting its application in fields requiring a certain degree of flexibility.

[0003] To improve the toughness of PLA, existing technologies typically add MBS-based or silicone-based toughening agents. However, when using MBS-based toughening agents, the refractive index difference between the MBS resin and the PLA matrix, along with the MBS's micron-sized particle dispersion, easily leads to light scattering. This results in a significant increase in the haze of the final consumable and a substantial decrease in transparency (transmittance), failing to meet the high transparency requirements of printing. While silicone-based toughening agents can maintain transparency to some extent, their toughening efficiency is relatively low, resulting in limited improvement in toughness. It is difficult to simultaneously achieve both transparency and toughness, making it unsuitable for the practical printing requirements that demand both high transparency and high toughness. Summary of the Invention

[0004] This invention provides a high-toughness and high-transparency PLA material, its preparation method, and printing consumables, to solve the technical problem that existing PLA materials cannot simultaneously achieve high transparency and high toughness.

[0005] To address the aforementioned technical problems, in a first aspect, the present invention provides a PLA material with high toughness and high transparency, comprising a PLA matrix and modified nanoparticles dispersed in the PLA matrix; wherein the modified nanoparticles have a core-shell structure, the core layer of the core-shell structure comprises silicon-titanium composite nanoparticles, and the shell layer of the core-shell structure comprises a hyperbranched polymer coated on the surface of the core layer.

[0006] The further technical solution is that the particle size of the silicon-titanium composite nanoparticles is 30-80nm.

[0007] The further technical solution is as follows: the silicon-titanium composite nanoparticles are formed by a hydrothermal synthesis reaction of a silicon source and a titanium source; the silicon source includes one or more of tetraethyl orthosilicate, methyl orthosilicate, propyl orthosilicate, butyl orthosilicate, dimethyldiethoxysilane, mercaptoethyltriethoxysilane, methyltriethoxysilane, and methyltrimethoxysilane; the titanium source includes one or more of titanium trichloride, titanium tetrachloride, titanium sulfate, butyl titanate, n-propyl titanate, tetraisopropyl titanate, titanium acetylacetone oxide, and titanate coupling agents; the hyperbranched polymer includes one or more of hyperbranched polyester, hyperbranched polyamide, and hyperbranched polyurethane.

[0008] Secondly, a method for preparing a high-toughness, high-transparency PLA material is provided, comprising: A modified nanoparticle liquid was obtained by mixing a hyperbranched polymer solution and a silicon-titanium composite nanosolution. The modified nanoparticle liquid was mixed with PLA resin, and after melt blending and granulation, PLA material particles were obtained.

[0009] The further technical solution is as follows: the mixture of hyperbranched polymer solution and silicon-titanium composite nanosolution to obtain modified nanoparticle liquid specifically includes: Under oil bath conditions, a hyperbranched polymer solution was added to the aged silicon-titanium composite nanosolution to coat and modify the silicon-titanium composite nanoparticles using the hyperbranched polymer, thus obtaining a composite modified nanosolution. The composite modified nano solution was concentrated to obtain a modified nanoparticle liquid.

[0010] A further technical solution is as follows: Under oil bath conditions, adding a hyperbranched polymer solution to the aged silicon-titanium composite nanosolution specifically includes: The silicon-titanium composite nano solution is aged for 1-72 hours, and then a hyperbranched polymer solution is added under an oil bath at 60-160℃, and the reaction is stirred for 4-24 hours.

[0011] The further technical solution is as follows: in the step of concentrating the composite modified nano solution, the concentration conditions are: evaporation and concentration at 50-90℃ for 1-6 hours, so that the effective substance content of the obtained modified nanoparticle liquid reaches 40-85%.

[0012] The further technical solution is as follows: the preparation method further includes: A silicon-titanium composite nanosolution was obtained by dissolving silicon and titanium sources in a mixed solution containing alcohol, water, and acid using a hydrothermal synthesis method.

[0013] The further technical solution is as follows: The method of hydrothermal synthesis involves dissolving silicon and titanium sources in a mixed solution containing alcohol, water, and acid to obtain a silicon-titanium composite nanosolution, specifically including: Silicon and titanium sources are dissolved in a mixed solution containing alcohol, water and acid, and the molar ratio of silicon source, titanium source, water, acid and alcohol is controlled to be (35-120):1:(20-35):(1-4):(30-60). The reaction is carried out at 20-100℃ for 4-48 hours to obtain silicon-titanium composite nano solution.

[0014] Thirdly, a 3D printing consumable is provided, wherein the 3D printing consumable is made of the above-mentioned high-toughness and high-transparency PLA material, or by drawing PLA material particles prepared by the above-described method into filaments.

[0015] Compared with existing technologies, the modified nanoparticles in the high-toughness and high-transparency PLA material of this invention have a core-shell structure. The core layer includes silicon-titanium composite nanoparticles, and the shell layer includes hyperbranched polymers coating the surface of the core layer. It is understood that this invention uses silicon-titanium composite nanoparticles as the core layer, allowing visible light to bypass the particles and continue propagating, thus eliminating the basis for light scattering from a physical optics perspective. Furthermore, by performing silicon-titanium composite in the core layer, the molar ratio of silicon and titanium can be controlled to uniformly composite two oxides with significantly different refractive indices at the molecular scale, obtaining composite nanoparticles with a high refractive index matching to the PLA matrix. This fundamentally suppresses interfacial light scattering and ensures straight-line light transmission. To prevent the nanoparticles from spontaneously agglomerating in the PLA matrix to form micron-sized aggregates and causing matching failure, this invention designs… The hyperbranched polymer coated on the surface of the core layer has two advantages. First, the highly branched molecular structure of the hyperbranched polymer generates a strong steric hindrance effect, forming a physical barrier that prevents particles from getting close to each other. Second, its excellent thermodynamic compatibility with the PLA matrix allows the modified nanoparticles to achieve nanoscale monodispersion in the PLA matrix, completely eliminating the light scattering hazards caused by agglomeration. As a result, the PLA material composed of the PLA matrix and the modified nanoparticles dispersed therein can effectively induce crazes and shear yielding and greatly improve the toughness of the material when subjected to external forces, by using the silicon-titanium composite nanoparticles in the core layer as stress concentration points. At the same time, it avoids the decrease in transparency caused by particle agglomeration, breaking through the technical bottleneck that traditional toughening inevitably leads to the degradation of transparency. It has both excellent transparency and high impact toughness. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of a method for preparing a high-toughness, high-transparency PLA material according to an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of a sub-process of a method for preparing a high-toughness, high-transparency PLA material according to an embodiment of the present invention.

[0018] Figure 3 This is an electron microscope image of the core-shell structure in the composite modified nanosolution prepared according to an embodiment of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to more clearly understand the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0020] This invention provides a high-toughness, high-transparency PLA material, comprising a PLA matrix and modified nanoparticles dispersed in the PLA matrix; wherein the modified nanoparticles have a core-shell structure, the core layer of the core-shell structure comprising silicon-titanium composite nanoparticles, and the shell layer comprising a hyperbranched polymer coated on the surface of the core layer. The particle size of the silicon-titanium composite nanoparticles is preferably 30-80 nm.

[0021] Specifically, refer to Figure 1 , Figure 1 This is a schematic flowchart illustrating a method for preparing a high-toughness, high-transparency PLA material according to an embodiment of the present invention. In the embodiment shown in the figures, the method for preparing the high-toughness, high-transparency PLA material includes: S101. Using a hydrothermal synthesis method, silicon and titanium sources are dissolved in a mixed solution containing alcohol, water, and acid to obtain a silicon-titanium composite nanosolution.

[0022] In this invention, the silicon-titanium composite nanoparticles are formed by a hydrothermal synthesis reaction of a silicon source and a titanium source; the silicon source may include one or more of tetraethyl orthosilicate, methyl orthosilicate, propyl orthosilicate, butyl orthosilicate, dimethyldiethoxysilane, mercaptoethyltriethoxysilane, methyltriethoxysilane, and methyltrimethoxysilane; the titanium source may include one or more of titanium trichloride, titanium tetrachloride, titanium sulfate, butyl titanate, n-propyl titanate, tetraisopropyl titanate, acetylacetone titanium oxide, and titanate coupling agents; the alcohol may be one or more of methanol, ethanol, isopropanol, n-butanol, and isobutanol; the acid may be one or more of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, and oxalic acid.

[0023] Specifically, this step includes: dissolving a silicon source and a titanium source in a mixed solution containing alcohol, water, and acid, preferably controlling the molar ratio of silicon source, titanium source, water, acid, and alcohol to be (35-120):1:(20-35):(1-4):(30-60), and reacting at 20-100°C for 4-48 hours to obtain a silicon-titanium composite nanosolution. For example, in some embodiments, a silicon source, a titanium source, and a mixed solution containing alcohol, water, and acid can be selected in proportion. During the reaction, the silicon source can be mixed with a portion of the mixed solution containing alcohol, water, and acid, and stirred at 40-70°C for 30-120 minutes for pre-hydrolysis; then, the titanium source and the remaining solution in the selected mixed solution containing alcohol, water, and acid are added, and the mixture is stirred at 60-75°C for 60-240 minutes to generate a silicon-titanium composite nanosolution. Understandably, in some other embodiments, the molar ratio of silicon source, titanium source, water, acid, and alcohol can be adjusted according to actual needs.

[0024] S102. Mix the hyperbranched polymer solution and the silicon-titanium composite nano solution to obtain the modified nanoparticle liquid.

[0025] In this invention, the hyperbranched polymer may include one or more of hyperbranched polyester, hyperbranched polyamide, and hyperbranched polyurethane. Preferably, the hyperbranched polymer may be a hyperbranched polyester or hyperbranched polyamide product with hydroxyl or carboxyl end groups, which can interact with the surface of silicon-titanium composite nanoparticles in the silicon-titanium composite nanosolution through hydrogen bonds or chemical bonds to ensure that the core-shell structure remains intact, thereby providing long-lasting toughening and light transmission functions.

[0026] like Figure 2 As shown, step S102 specifically includes the following steps S1021-S1022: S1021. Under oil bath conditions, a hyperbranched polymer solution is added to the aged silicon-titanium composite nanosolution to coat and modify the silicon-titanium composite nanoparticles using the hyperbranched polymer, thereby obtaining a composite modified nanosolution.

[0027] Specifically, the silicon-titanium composite nanosolution can be aged for 1-72 hours, then a hyperbranched polymer solution can be added under an oil bath at 60-160℃, and the reaction can be stirred for 4-24 hours to obtain a composite modified nanosolution, that is, a solution containing, for example, a silicon-titanium composite nanosolution. Figure 3 The solution shown is a modified nanoparticle with a core-shell structure.

[0028] S1022. The composite modified nano solution is concentrated to obtain modified nanoparticle liquid.

[0029] In this step, the concentration conditions can be: evaporation and concentration at 50-90℃ for 1-6 hours, so that the effective substance content of the obtained modified nanoparticle liquid reaches 40-85%. That is, the concentration step can be ended when the mass percentage of the modified nanoparticles coated with hyperbranched polymer in the total mass of the modified nanoparticle liquid reaches any content between 40-85%, and the modified nanoparticle liquid is obtained.

[0030] S103. The obtained modified nanoparticle liquid is mixed with PLA resin, and after melt blending and granulation, PLA material particles are obtained.

[0031] In this step, the modified nanoparticle liquid and PLA resin are added to a twin-screw extruder for granulation modification according to a mass ratio of modified nanoparticle liquid to PLA resin of (0.02-0.1):1, to obtain PLA material particles comprising a PLA matrix and modified nanoparticles dispersed in the PLA matrix. Preferably, the extrusion temperature of the twin-screw extruder can be 140-190℃, and the rotation speed can be 150-450 rpm.

[0032] In this invention, the hyperbranched polymer, due to its highly branched molecular topology, forms a thick organic shell on the surface of modified nanoparticles. When the particles approach each other, the conformational freedom of the surface branched chains is compressed, generating strong osmotic and elastic repulsion, forming a physical barrier that prevents particle aggregation. Furthermore, this organic shell endows the nanoparticles with similar polar characteristics and interfacial energy to the PLA matrix. Through segment entanglement or interactions between ester groups, the nanoparticles become thermodynamically compatible with PLA, achieving uniform monodispersion at the nanoscale, eliminating light scattering, and efficiently transferring stress.

[0033] In this invention, silicon-titanium composite nanoparticles are used as the core layer, and the particle size of the core layer is controlled within the subwavelength scale of 30-80 nm. This allows visible light to bypass the particles and continue propagating, eliminating the basis for light scattering from a physical optics perspective. Furthermore, by controlling the molar ratio of silicon and titanium in the core layer, the two oxides with significantly different refractive indices can be uniformly composited at the molecular scale, resulting in composite nanoparticles with a refractive index highly matched to the PLA matrix. This fundamentally suppresses interfacial light scattering and ensures straight-line light transmission. To prevent the nanoparticles from spontaneously agglomerating in the PLA matrix to form micron-sized aggregates and causing mismatch, this invention incorporates a hyperbranched polymer coated on the surface of the core layer. This hyperbranched polymer, on the one hand, utilizes its highly branched structure... The modified molecular structure generates a strong steric hindrance effect, forming a physical barrier that prevents particles from approaching each other. Furthermore, its excellent thermodynamic compatibility with the PLA matrix allows the modified nanoparticles to achieve nanoscale monodispersion within the PLA matrix, completely eliminating the light scattering risks caused by aggregation. This results in PLA materials composed of the PLA matrix and the aforementioned modified nanoparticles, which, under external force, utilize the silicon-titanium composite nanoparticles in the core layer as stress concentration points, effectively inducing crazes and shear yielding, significantly improving material toughness. Simultaneously, it avoids the decrease in transparency caused by particle aggregation or phase separation, breaking through the technical bottleneck that traditional toughening inevitably leads to a deterioration in transparency. This invention combines excellent transparency and high impact toughness. It can be seen that this invention prepares silicon-titanium composite nanoparticles of specific size and structure in situ via hydrothermal synthesis, and modifies their surface using hyperbranched polymers, introducing them as a highly efficient and transparent toughening agent into the PLA matrix, thereby solving the technical problem of the inability to simultaneously achieve transparency and toughness in PLA materials.

[0034] Furthermore, the present invention can also provide a 3D printing consumable, which can be made by drawing high-toughness and high-transparency PLA material particles obtained by the above method into filaments. Specifically, the PLA material particles can be added to a 3D printing consumable filament drawing machine for melt drawing to obtain a 3D printing consumable with both high toughness and high transparency. Preferably, the temperature of the filament drawing machine can be 160-210℃, and the linear speed can be 60-180 m / min.

[0035] The preparation method of the 3D printing consumable with high toughness and high transparency of the present invention will be described below with reference to specific embodiments.

[0036] Example 1 (1) Take 44.6 mL of tetraethyl orthosilicate (TEOS), 44.4 mL of anhydrous ethanol (EtOH), 3.6 mL of water and 1 μL of hydrochloric acid (HCl), and stir at 40-70℃ for 30-120 min at a stirring speed of 400-2000 rpm to allow partial hydrolysis of tetraethyl orthosilicate; then add 8.5 mL of tetrabutyl titanate (TBOT), 25 mL of ethanol, 5 mL of hydrochloric acid and 20 mL of water, and stir at 60-75℃ at 200-1500 rpm for 60-240 min to obtain a silicon-titanium composite nano solution; (2) Add 14.4 mL of hydrochloric acid, 0.8 mL of water and 93.2 mL of anhydrous ethanol to the silicon-titanium composite nano solution and age for 6 hours. After aging, add 38 mL of hyperbranched polymer solution (such as hyperbranched polyester solution) and react for 8 hours in a water bath at 70°C to obtain a composite modified nano solution. Then, rotary evaporate at 75°C for 3 hours to obtain a modified nanoparticle liquid with an effective substance content of 78%. (3) According to the mass ratio, take 5% of the modified nanoparticle liquid and add it to 95% PLA resin, stir evenly, and add it to the twin-screw extruder for granulation. The temperature of each section of the extruder from the feed section to the die head is set to 140℃, 160℃, 170℃, 175℃, 180℃, 185℃, 185℃, 180℃, 175℃, and 170℃ respectively, and the screw speed is 400 rpm to obtain PLA material particles; (4) After drying PLA material particles at 50°C for 4 hours, they are added to a single-screw wire drawing machine for wire drawing. The temperature of each section of the wire drawing machine from the feeding section to the die head is set to 160°C, 175°C, 185°C, 190°C, 190°C and 185°C respectively, and the screw speed is 30 rpm, to obtain 3D printing consumables with a diameter of 1.75 mm.

[0037] The 3D printing consumables obtained above were subjected to various performance tests, and the data obtained are as follows: melt flow index 8.61 g / 10 min, light transmittance 90.3%, tensile strength 51 MPa, elongation at break 13.2%, and simply supported notched impact strength 6.9 kJ / m². 2 The simply supported unnotched impact strength is 18.4 kJ / m. 2The overall model printing effect score was 88 points. Understandably, the above data are the average of multiple parallel tests. Melt flow index was tested according to GB / T 3682-2000 standard at 190℃ and a load of 2.16kg; light transmittance was tested according to GB / T 2410-2008 standard with a sample thickness of 2mm; tensile strength and elongation at break were tested according to GB / T 1040.2-2006 standard at a tensile rate of 50mm / min; simply supported notched impact strength and simply supported unnotched impact strength were tested according to GB / T 1043.1-2008 standard. The overall model printing effect score is a comprehensive score of indicators such as interlayer adhesion, surface finish, and detail reproduction of the printed part of the standard test model, with a maximum score of 100 points.

[0038] Example 2 (1) Take 44.6 mL of tetraethyl orthosilicate (TEOS), 44.4 mL of anhydrous ethanol (EtOH), 3.6 mL of water and 1 μL of hydrochloric acid (HCl), and stir at 40-70℃ for 30-120 min at a stirring speed of 400-2000 rpm to allow partial hydrolysis of tetraethyl orthosilicate; then add 4.25 mL of tetrabutyl titanate (TBOT), 12.5 mL of ethanol, 2.5 mL of hydrochloric acid and 10 mL of water, and stir at 60-75℃ at 200-1500 rpm for 60-240 min to obtain a silicon-titanium composite nano solution; (2) Add 14.4 mL of hydrochloric acid, 0.8 mL of water and 93.2 mL of anhydrous ethanol to the silicon-titanium composite nano solution and age for 6 hours. After aging, add 38 mL of hyperbranched polymer solution and react for 8 hours in a water bath at 70°C to obtain a composite modified nano solution. Then, rotary evaporate at 75°C for 3 hours to obtain a modified nanoparticle liquid with an effective substance content of 78%. (3) According to the mass ratio, take 5 parts by weight of modified nanoparticle liquid and add it to 95 parts by weight of PLA resin. Stir evenly and add it to a twin-screw extruder for granulation. The temperature of each section of the extruder from the feed section to the die head is set to 140℃, 160℃, 170℃, 175℃, 180℃, 185℃, 185℃, 180℃, 175℃, and 170℃ respectively. The screw speed is 400 rpm to obtain PLA material particles. (4) After drying PLA material particles at 50°C for 4 hours, they are added to a single-screw wire drawing machine for wire drawing. The temperature of each section of the wire drawing machine from the feeding section to the die head is set to 160°C, 175°C, 185°C, 190°C, 190°C and 185°C respectively, and the screw speed is 30 rpm, to obtain 3D printing consumables with a diameter of 1.75 mm.

[0039] Compared to Example 1, this example only changes the amount of titanium source, alcohol, water, and acid mixture in step (1) of Example 1; the remaining steps are the same. The 3D printing consumables obtained in Example 2 were subjected to various performance tests using the same test standards / conditions as in Example 1. The data obtained are as follows: melt flow index 7.97 g / 10 min, light transmittance 87.9%, tensile strength 57 MPa, elongation at break 10.2%, and notched impact strength 4.9 kJ / m². 2 The impact strength of a simply supported, unnotched structure is 17.1 kJ / m. 2 The overall model printing effect score was 81 points.

[0040] Example 3 (1) Take 44.6 mL of tetraethyl orthosilicate (TEOS), 44.4 mL of anhydrous ethanol (EtOH), 3.6 mL of water and 8.4 mL of acetic acid (CH3COOH), and stir at 40-70℃ for 30-120 min at a stirring speed of 400-2000 rpm to allow partial hydrolysis of tetraethyl orthosilicate; then add 4.25 mL of tetrabutyl titanate (TBOT), 12.5 mL of ethanol, 13.6 mL of acetic acid and 10 mL of water, and stir at 60-75℃ at 200-1500 rpm for 60-240 min to obtain a silicon-titanium composite nano solution; (2) Add 58.8 mL of acetic acid, 0.8 mL of water and 93.2 mL of anhydrous ethanol to the silicon-titanium composite nano solution and age for 6 hours. After aging, add 38 mL of hyperbranched polymer solution and react for 8 hours in a water bath at 70°C to obtain a composite modified nano solution. Then, rotary evaporate at 75°C for 3 hours to obtain a modified nanoparticle liquid with an effective substance content of 78%. (3) and (4) are the same as in Examples 1 and 2, and will not be repeated here.

[0041] Compared to Example 2, this example only replaces the hydrochloric acid with acetic acid and adjusts the acetic acid content accordingly. The 3D printing consumables obtained in Example 3 were subjected to the same test standards / conditions as in Example 1 for various performance tests, and the data obtained are as follows: melt flow index 6.75 g / 10 min, light transmittance 89.6%, tensile strength 53 MPa, elongation at break 8.7%, and notched impact strength 5.6 kJ / m². 2 The impact strength of a simply supported, unnotched specimen is 17.2 kJ / m. 2 The overall model printing effect score is 85 points.

[0042] Example 4 (1) Take 44.6 mL of tetraethyl orthosilicate (TEOS), 44.4 mL of anhydrous ethanol (EtOH), 3.6 mL of water and 1 μL of hydrochloric acid (HCl), and stir at 40-70℃ for 30-120 min at a stirring speed of 400-2000 rpm to allow partial hydrolysis of tetraethyl orthosilicate; then add 4.25 mL of tetrabutyl titanate (TBOT), 12.5 mL of ethanol, 2.5 mL of hydrochloric acid and 10 mL of water, and stir at 60-75℃ at 200-1500 rpm for 60-240 min to obtain a silicon-titanium composite nano solution; (2) Add 14.4 mL of hydrochloric acid, 0.8 mL of water and 93.2 mL of anhydrous ethanol to the silicon-titanium composite nano solution and age for 6 hours. After aging, add 76 mL of hyperbranched polymer solution and react for 8 hours in a water bath at 70°C to obtain a composite modified nano solution. Then, rotary evaporate at 75°C for 4 hours to obtain a modified nanoparticle liquid with an effective substance content of 85%. (3) and (4) are the same as in Examples 1 and 2, and will not be repeated here.

[0043] Compared to Example 1, this example only changes the amount of hyperbranched polymer solution used in step (2) of Example 1 and the content of effective substances in the modified nanoparticle liquid obtained after concentration. The 3D printing consumables obtained in Example 4 were subjected to various performance tests using the same test standards / conditions as in Example 1. The data obtained are as follows: melt flow index 8.13 g / 10 min, light transmittance 90.9%, tensile strength 55 MPa, elongation at break 16.3%, and notched impact strength 7.3 kJ / m². 2 The simply supported unnotched impact strength is 18.9 kJ / m. 2 The overall model printing effect score is 91 points.

[0044] Comparative Example 1 Unmodified PLA resin was dried at 50°C for 4 hours and then fed into a single-screw wire drawing machine for wire drawing. The temperatures of each section of the wire drawing machine from the feed section to the die head were set to 160°C, 175°C, 185°C, 190°C, 190°C and 185°C respectively, and the screw speed was 30 rpm, resulting in 3D printing consumables with a diameter of 1.75 mm.

[0045] The 3D printing consumables obtained in Comparative Example 1 were subjected to the same test standards / conditions as in Example 1 for various performance tests. The data obtained are as follows: melt flow index 7.86 g / 10 min (190℃, 2.16 kg), light transmittance 91.1%, tensile strength 63 MPa, elongation at break 3.4%, and notched impact strength 1.2 kJ / m². 2 The simply supported unnotched impact strength is 3.1 kJ / m. 2The overall model printing effect score was 83 points.

[0046] As can be seen from the above, the light transmittance of the 3D printing consumable prepared in Example 1 of the present invention is 90.3%, which is close to the light transmittance of the 3D printing consumable prepared from pure PLA raw material. At the same time, the elongation at break of the 3D printing consumable prepared in Example 1 is significantly improved to 13.2%, and the notched impact strength of the simply supported material reaches 6.9 kJ / m. 2 It combines high transparency with high toughness.

[0047] Comparative Example 2 According to the mass ratio, 5 parts by weight of MBS toughening agent and 95 parts by weight of PLA resin were mixed evenly and added to a twin-screw extruder for granulation. The temperature of each section of the extruder from the feed section to the die head was set sequentially to 140℃, 160℃, 170℃, 175℃, 180℃, 185℃, 185℃, 180℃, 175℃, and 170℃, and the screw speed was 400 rpm, to obtain PLA material particles. After drying the obtained PLA material particles at 50℃ for 4 hours, they were added to a single-screw wire drawing machine for wire drawing. The temperature of each section of the wire drawing machine from the feed section to the die head was set sequentially to 160℃, 175℃, 185℃, 190℃, 190℃, and 185℃, and the screw speed was 30 rpm, to obtain 3D printing consumables with a diameter of 1.75 mm.

[0048] In Comparative Example 2, the PLA resin was toughened using MBS toughening agent. The 3D printing consumables obtained in Comparative Example 2 were subjected to the same test standards / conditions as in Example 1 for various performance tests. The data obtained are shown below: melt flow index 6.93 g / 10 min, light transmittance 86.1%, tensile strength 49 MPa, elongation at break 9.7%, and simply supported notched impact strength 4.7 kJ / m². 2 The impact strength of a simply supported, unnotched structure is 16.8 kJ / m. 2 The overall model printing effect score was 86 points. It can be seen that, compared with Comparative Example 1, although the elongation at break of the consumable in Comparative Example 2 increased to 9.7%, the light transmittance dropped significantly to 86.1%, which reflects the shortcomings of the traditional solution that sacrifices transparency for toughness.

[0049] Comparative Example 3 The method is similar to that in Example 1, except that step (2) is omitted, in which 38 mL of hyperbranched polymer solution is added and reacted for 8 hours in a 70°C water bath. After aging, the solution is rotary evaporated at 75°C for 3 hours to obtain a nanoparticle liquid with an effective substance content of 78%. The remaining steps are the same.

[0050] In Comparative Example 3, no hyperbranched polymer was used for coating modification. The 3D printing consumables obtained in Comparative Example 3 were tested for various properties using the same test standards / conditions as in Example 1. The data obtained are as follows: melt flow index 9.61 g / 10 min, light transmittance 83.2%, tensile strength 48 MPa, elongation at break 9.1%, and simply supported notched impact strength 3.8 kJ / m. 2 The simply supported unnotched impact strength is 15.3 kJ / m. 2 The overall model printing effect score is 80 points.

[0051] As can be seen, Comparative Example 3, due to nanoparticle aggregation, has a light transmittance of only 83.2%, and the improvement in toughness is also limited, indicating that nanoparticles without hyperbranching coating modification cannot simultaneously achieve transparency and toughness. In contrast, Examples 1 to 4 of this invention, through the synergistic scheme of "silicon-titanium composite + hyperbranching coating," show that Example 1 achieves a light transmittance of 90.3% (close to 91.1% of pure PLA), while simultaneously significantly increasing the elongation at break to 13.2% and the simply supported notched impact strength to 6.9 kJ / m². 2 Example 4: By increasing the amount of hyperbranched resin and improving the concentration of nanoparticle liquid, the light transmittance reached 90.9%, the elongation at break was further increased to 16.3%, and the simply supported notched impact strength reached 7.3 kJ / m. 2 The prepared PLA materials and consumables both possess high transparency and high toughness.

[0052] Comparative Example 4 (1) Take 44.6 mL of tetraethyl orthosilicate (TEOS), 44.4 mL of anhydrous ethanol (EtOH), 3.6 mL of water and 1 μL of hydrochloric acid (HCl), and stir it at 40-70℃ for 30-120 min. The stirring speed can be 400-2000 rpm to hydrolyze the tetraethyl orthosilicate. (2) Add 14.4 mL of hydrochloric acid, 0.8 mL of water and 93.2 mL of anhydrous ethanol to the solution after hydrolysis in step (1), and age for 6 hours. After aging, rotary evaporate at 75°C for 3 hours to obtain a nanoparticle liquid with an effective substance content of 66%. (3) and (4) are the same as in Examples 1 and 2, and will not be repeated here.

[0053] Pure silicon nanoparticles (PL) were prepared in Comparative Example 4. The 3D printing consumables obtained in Comparative Example 4 were subjected to various performance tests using the same testing standards / conditions as in Example 1. The data obtained are shown below: melt flow index 8.16 g / 10 min, light transmittance 86.7%, tensile strength 41 MPa, elongation at break 8.7%, and simply supported notched impact strength 3.1 kJ / m². 2 The simply supported unnotched impact strength is 13.2 kJ / m. 2The overall model printing effect score was 79 points.

[0054] Comparative Example 5 (1) Take 8.5 mL of tetrabutyl titanate (TBOT), 25 mL of ethanol, 5 mL of hydrochloric acid and 20 mL of water, and stir at 60-75℃ and 200-1500 rpm for 60-240 min. (2) Add 14.4 mL of hydrochloric acid, 0.8 mL of water and 93.2 mL of anhydrous ethanol to the solution obtained in step (1), and age for 6 hours. After aging, rotary evaporate at 75°C for 3 hours to obtain a nanoparticle liquid with an effective substance content of 73%. (3) and (4) are the same as in Examples 1 and 2, and will not be repeated here.

[0055] Pure titanium nanoparticles (PL) were prepared in Comparative Example 5. The 3D printing consumables obtained in Comparative Example 5 were subjected to various performance tests using the same testing standards / conditions as in Example 1. The data obtained are shown below: melt flow index 8.91 g / 10 min, light transmittance 78.6%, tensile strength 46 MPa, elongation at break 6.9%, and simply supported notched impact strength 2.7 kJ / m². 2 The simply supported unnotched impact strength is 9.6 kJ / m. 2 The overall model printing effect score was 72 points.

[0056] As shown above, the light transmittance and toughening effect of the consumables prepared in Comparative Examples 4 and 5 are not ideal.

[0057] In summary, this invention maintains high transparency while enhancing the toughness of PLA materials. Through the synergistic effect of "silicon-titanium composite + hyperbranched coating," the PLA material, composed of a PLA matrix and the aforementioned modified nanoparticles dispersed therein, can effectively induce crazes and shear yielding by utilizing the silicon-titanium composite nanoparticles in the core layer as stress concentration points when subjected to external forces, thus significantly improving the material's toughness. At the same time, it avoids the decrease in transparency caused by particle aggregation or phase separation. This invention breaks through the technical bottleneck that traditional toughening inevitably leads to a deterioration in transparency, thus achieving both excellent transparency and high impact toughness.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Those skilled in the art can make various equivalent changes and improvements based on the above embodiments, and all equivalent variations or modifications made within the scope of the claims should fall within the protection scope of the present invention.

Claims

1. A high-toughness, high-transparency PLA material, characterized in that, The invention comprises a PLA matrix and modified nanoparticles dispersed in the PLA matrix; wherein the modified nanoparticles have a core-shell structure, the core layer of the core-shell structure comprises silicon-titanium composite nanoparticles, and the shell layer of the core-shell structure comprises hyperbranched polymers coated on the surface of the core layer.

2. The high-toughness, high-transparency PLA material as described in claim 1, characterized in that, The silicon-titanium composite nanoparticles have a particle size of 30-80 nm.

3. The high-toughness, high-transparency PLA material as described in claim 1, characterized in that, The silicon-titanium composite nanoparticles are formed by a hydrothermal synthesis reaction of a silicon source and a titanium source; the silicon source includes one or more of tetraethyl orthosilicate, methyl orthosilicate, propyl orthosilicate, butyl orthosilicate, dimethyldiethoxysilane, mercaptoethyltriethoxysilane, methyltriethoxysilane, and methyltrimethoxysilane; the titanium source includes one or more of titanium trichloride, titanium tetrachloride, titanium sulfate, butyl titanate, n-propyl titanate, tetraisopropyl titanate, titanium acetylacetone oxide, and titanate coupling agents; the hyperbranched polymer includes one or more of hyperbranched polyester, hyperbranched polyamide, and hyperbranched polyurethane.

4. A method for preparing a high-toughness, high-transparency PLA material, characterized in that, include: A modified nanoparticle liquid was obtained by mixing a hyperbranched polymer solution and a silicon-titanium composite nanosolution. The modified nanoparticle liquid was mixed with PLA resin, and after melt blending and granulation, PLA material particles were obtained.

5. The method for preparing the high-toughness and high-transparency PLA material as described in claim 4, characterized in that, The process of mixing the hyperbranched polymer solution and the silicon-titanium composite nanosolution to obtain the modified nanoparticle liquid specifically includes: Under oil bath conditions, a hyperbranched polymer solution was added to the aged silicon-titanium composite nanosolution to coat and modify the silicon-titanium composite nanoparticles using the hyperbranched polymer, thus obtaining a composite modified nanosolution. The composite modified nano solution was concentrated to obtain a modified nanoparticle liquid.

6. The method for preparing the high-toughness, high-transparency PLA material as described in claim 5, characterized in that, The process of adding a hyperbranched polymer solution to the aged silicon-titanium composite nanosolution under oil bath conditions specifically includes: The silicon-titanium composite nano solution is aged for 1-72 hours, and then a hyperbranched polymer solution is added under an oil bath at 60-160℃, and the reaction is stirred for 4-24 hours.

7. The method for preparing the high-toughness, high-transparency PLA material as described in claim 5, characterized in that, In the step of concentrating the composite modified nano solution, the concentration conditions are: evaporation and concentration at 50-90℃ for 1-6 hours, so that the effective substance content of the obtained modified nanoparticle liquid reaches 40-85%.

8. The method for preparing the high-toughness and high-transparency PLA material as described in claim 4, characterized in that, The preparation method further includes: A silicon-titanium composite nanosolution was obtained by dissolving silicon and titanium sources in a mixed solution containing alcohol, water, and acid using a hydrothermal synthesis method.

9. The method for preparing the high-toughness, high-transparency PLA material as described in claim 8, characterized in that, The method of hydrothermal synthesis involves dissolving silicon and titanium sources in a mixed solution containing alcohol, water, and acid to obtain a silicon-titanium composite nanosolution, specifically including: Silicon and titanium sources are dissolved in a mixed solution containing alcohol, water and acid, and the molar ratio of silicon source, titanium source, water, acid and alcohol is controlled to be (35-120):1:(20-35):(1-4):(30-60). The reaction is carried out at 20-100℃ for 4-48 hours to obtain silicon-titanium composite nano solution.

10. A 3D printing consumable, characterized in that, The 3D printing consumable is made of high-toughness and high-transparency PLA material as described in any one of claims 1-3, or by drawing PLA material particles prepared by the method described in any one of claims 4-9.

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