Modified polylactic acid composite photosensitive resin for light-cured 3D printing and preparation method thereof

Abstract

The application discloses a modified polylactic acid composite photosensitive resin for light-cured 3D printing and a preparation method thereof, and the modified polylactic acid composite photosensitive resin comprises the following components in mass fraction: 65-75% of photosensitive remote chelating oligomeric lactic acid, 0.5-5% of a photoinitiator and 20-30% of a diluent, wherein the photosensitive remote chelating oligomeric lactic acid is prepared by dehydration polymerization of L-lactic acid as a main body and a chelating center molecule, and then end group grafting of a vinyl grafting molecule; the chelating center molecule is one of succinic acid, trimesic acid and ethylenediaminetetraacetic acid, and the components are uniformly mixed and stored in the dark. The modified PLA composite photosensitive resin has good photosensitivity, can be effectively applied to DLP light-cured 3D printing technology, and meanwhile, the excellent biocompatibility and degradability of PLA are maintained, the printing precision, surface smoothness and mechanical properties of the modified PLA composite photosensitive resin are all superior to those of a traditional FDM printed PLA product, and the product has good mechanical properties and good thermal stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biodegradable materials, and particularly relates to a modified polylactic acid composite photosensitive resin for light-curing 3D printing and a preparation method thereof. BACKGROUND

[0002] Polylactic acid (PLA) is a widely used biodegradable polymer in packaging and medical industries. Due to its excellent biocompatibility and biodegradability, it has great potential in biological scaffolds and drug delivery systems. However, the traditional manufacturing methods and high cost limit its application, resulting in that most of the biological scaffold products are standardized production, and customized products are rare and expensive. Given the diversity of patient needs, personalized scaffold products are more in line with their specific needs.

[0003] With the advancement of 3D printing technology, the possibility of realizing low-cost customized products is increasingly high. In particular, the personalized customization of PLA through 3D printing technology has attracted widespread attention. Currently, fused deposition modeling (FDM) is the main 3D printing technology for processing PLA, which builds objects by heating PLA filaments to the melting point and then stacking layer by layer. However, the FDM printed products have rough surface, low precision, slow printing speed and low efficiency, which is not ideal in the field of biological scaffolds.

[0004] In contrast, digital light processing (DLP) printing technology is known for its high precision and efficiency, and can print products with smooth surface and rich details, effectively overcoming the shortcomings of FDM technology. However, due to the lack of photoactive groups in the molecular structure of PLA, it cannot be directly used in the light-curing process.

[0005] Currently, in order to improve the photosensitivity of PLA, methods such as introducing photo-initiators or adding other photosensitive resins are usually adopted. However, these methods often lead to a decrease in the mechanical properties of the material or produce toxicity, limiting their application in the biomedical field.

[0006] Therefore, the development of a new type of modified polylactic acid composite photosensitive resin for light-curing 3D printing with good photosensitivity while maintaining the excellent properties of PLA is of great significance for promoting the application of 3D printing technology in the biomedical field. SUMMARY

[0007] Therefore, the development of a new type of modified polylactic acid composite photosensitive resin for light-curing 3D printing with good photosensitivity while maintaining the excellent properties of PLA is of great significance for promoting the application of 3D printing technology in the biomedical field.

[0008] In order to achieve the above-mentioned purpose, the application provides the following technical scheme:

[0009] A modified polylactic acid composite photosensitive resin for light-cured 3D printing, comprising the following components in mass fraction:

[0010] Photosensitive remote chelating oligomeric lactic acid 65-75%;

[0011] Photoinitiator 0.5-5%;

[0012] Diluent 20-30%;

[0013] Wherein, the photosensitive remote chelating oligomeric lactic acid is made of L-lactic acid as the main body, dehydrated polymerization with chelating center molecules, and end group grafting of vinyl grafting molecules; the chelating center molecules are one of succinic acid (DBP), benzene-1, 3, 5-tricarboxylic acid (BTC) and ethylenediaminetetraacetic acid (EDTA).

[0014] Preferably, the photoinitiator is one of IRGACURE 819, diphenyl-(2,4,6-trimethylbenzoyl) phosphine oxide (TPO) and camphorquinone.

[0015] Preferably, the diluent is one of N-vinylpyrrolidone, monofunctional styrene (St), vinylpyrrolidone (NVP), vinyl acetate (VA), butyl acrylate (BA), isooctyl acrylate (EHA), (methyl) acrylic acid hydroxy ester (HEA, HEMA, HPA), difunctional 1, 6-hexanediol diacrylate (HDDA), tripropylene glycol diacrylate (TPGDA), neopentyl glycol diacrylate (NPGDA), and multifunctional trimethylolpropane triacrylate (TMPTA).

[0016] Preferably, the vinyl grafting molecule is one of glycidyl methacrylate or acrylic anhydride.

[0017] Preferably, the molar ratio of L-lactic acid, chelating center molecules and vinyl grafting molecules is 1:40:5.

[0018] Preferably, the preparation process of the photosensitive remote chelating oligomeric lactic acid is as follows: L-lactic acid and chelating center molecules are added to the reactor, then toluene is added as a water agent, and then the reactor is sequentially reacted at 90℃ and 100℃ for 1 hour each, then the catalyst stannous octoate is continuously added, the reactor is pumped to vacuum, then the reactor is sequentially reacted at 120℃ and 140℃ for 2 hours each, then the temperature is raised to 160℃ and reacted for 20 hours, then the temperature is lowered to 120℃, then the vinyl grafting molecule is added and reacted for 4 hours, and then the photosensitive remote chelating oligomeric lactic acid is obtained.

[0019] The application also provides a preparation method of the modified polylactic acid composite photosensitive resin for light-cured 3D printing, which comprises uniformly mixing the components and storing in the dark.

[0020] The present application has the advantages of:

[0021] The modified PLA composite photosensitive resin of the present application has good photosensitivity, can be effectively applied to DLP photocuring 3D printing technology, and at the same time maintains the excellent biocompatibility and degradability of PLA, and is superior to the conventional FDM printed PLA product in printing precision, surface smoothness and mechanical properties, and has good mechanical properties and good thermal stability. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 DSC curve of the photosensitive telechelate oligolactic acid prepared for Example 2, Example 3 and Comparative Example 1. DETAILED DESCRIPTION

[0023] The present application will be further described in detail below in combination with the drawings and specific examples.

[0024] Example 1

[0025] A modified polylactic acid composite photosensitive resin for photocuring 3D printing: the mass fraction of photosensitive telechelate oligolactic acid is 72.5%; the mass fraction of photoinitiator is 1.0%; and the mass fraction of diluent is 26.5%. Among them, the chelating center molecule is succinic acid (SA), the vinyl grafting molecule is glycidyl methacrylate, the diluent is N-vinyl pyrrolidone (NVP), and the photoinitiator is IRGACURE 819.

[0026] 1. A photosensitive telechelate oligolactic acid preparation method, comprising the following steps:

[0027] First, the chelating center molecule and L-lactic acid are added to a three-necked round-bottom flask in a molar ratio of 1:40, and toluene is added as a water-carrying agent. Then, the reaction is carried out at 90℃ and 100℃ for 1 hour respectively, then the catalyst stannous octoate is added, the circulating water vacuum pump is opened to vacuum, and then the reaction is carried out at 120℃ and 140℃ for 2 hours respectively, and then the temperature is raised to 160℃ for 20 hours, then the temperature is lowered to 120℃, the vinyl grafting molecule (L-lactic acid: vinyl grafting molecule = 1:5) is added, and the reaction is continued for 4 hours, and finally the photosensitive telechelate oligolactic acid is obtained.

[0028] 2. A modified polylactic acid composite photosensitive resin preparation method for photocuring 3D printing, the photosensitive telechelate oligolactic acid, photoinitiator and diluent are mixed uniformly according to the formula proportion, the mixing time is 20 minutes, and the mixture is stored in the dark, which is the modified polylactic acid composite photosensitive resin for photocuring 3D printing.

[0029] 3、3D printing process: the modified polylactic acid composite photosensitive resin for photocuring 3D printing is put into the 3D printer, and 3D printing is carried out, wherein the 3D printer is a magic precise DLP-3D printer, the light source of the 3D printer is an ultraviolet light source with a wavelength of 540 nm, the printing speed of the 3D printer is 1 mm / s, the printing precision of the 3D printer is 0.01 mm, the printing layer thickness of the 3D printer is 0.073 mm, and the printing temperature of the 3D printer is room temperature.

[0030] Example 2

[0031] A modified polylactic acid composite photosensitive resin for photocuring 3D printing: the mass fraction of photosensitive remote chelating oligomeric lactic acid is 72.5%; the mass fraction of photoinitiator is 1.0%; the mass fraction of diluent is 26.5%. Among them, the chelating center molecule is trimesic acid (H3TBC), the vinyl grafting molecule is glycidyl methacrylate, the diluent is N-vinyl pyrrolidone (NVP), and the photoinitiator is IRGACURE 819.

[0032] 1. A method for preparing photosensitive remote chelating oligomeric lactic acid, comprising the following steps:

[0033] First, the chelating center molecule and L-lactic acid are added to a three-necked round-bottom flask in a molar ratio of 1:40, and toluene is added as a water-carrying agent. Then, the reaction is carried out at 90℃ and 100℃ for 1 hour respectively, followed by adding a catalyst stannous octoate. After vacuumizing by opening the circulating water vacuum pump, the reaction is carried out at 120℃ and 140℃ for 2 hours respectively, and then the temperature is raised to 160℃ for 20 hours. Then, the temperature is lowered to 120℃, and the vinyl grafting molecule (L-lactic acid: vinyl grafting molecule = 1:5) is added for continuous reaction for 4 hours. Finally, the photosensitive remote chelating oligomeric lactic acid is obtained.

[0034] 2. A method for preparing a modified polylactic acid composite photosensitive resin for photocuring 3D printing, the photosensitive remote chelating oligomeric lactic acid, the photoinitiator and the diluent are mixed uniformly according to the formula proportion, the mixing time is 20 minutes, and the mixture is stored in the dark. The modified polylactic acid composite photosensitive resin for photocuring 3D printing is obtained.

[0035] 3. 3D printing process: the modified polylactic acid composite photosensitive resin for photocuring 3D printing is put into the 3D printer, and 3D printing is carried out, wherein the 3D printer is a magic precise DLP-3D printer, the light source of the 3D printer is an ultraviolet light source with a wavelength of 540 nm, the printing speed of the 3D printer is 1 mm / s, the printing precision of the 3D printer is 0.01 mm, the printing layer thickness of the 3D printer is 0.073 mm, and the printing temperature of the 3D printer is room temperature.

[0036] Example 3

[0037] A modified polylactic acid composite photosensitive resin for light-cured 3D printing: the mass fraction of photosensitive remote chelation oligomeric lactic acid is 72.5%; the mass fraction of photoinitiator is 1.0%; the mass fraction of diluent is 26.5%. Among them, the chelation center molecule is ethylenediaminetetraacetic acid (EDTA), the vinyl grafting molecule is glycidyl methacrylate, the diluent is N-vinyl pyrrolidone (NVP), and the photoinitiator is IRGACURE 819.

[0038] 1. A method for preparing photosensitive remote chelation oligomeric lactic acid, comprising the following steps:

[0039] First, the chelation center molecule and L-lactic acid are added to a three-mouth round-bottom flask in a molar ratio of 1:40, and toluene is added as a water-carrying agent. Then, the reaction is carried out at 90℃ and 100℃ for 1 hour respectively, followed by adding a catalyst stannous octoate. After vacuumizing by opening the circulating water vacuum pump, the reaction is carried out at 120℃ and 140℃ for 2 hours respectively, and then the temperature is raised to 160℃ for 20 hours. Then, the temperature is lowered to 120℃, and the vinyl grafting molecule (L-lactic acid: vinyl grafting molecule = 1:5) is added for continuous reaction for 4 hours, and finally the photosensitive remote chelation oligomeric lactic acid is obtained.

[0040] 2. A method for preparing a modified polylactic acid composite photosensitive resin for light-cured 3D printing, wherein the photosensitive remote chelation oligomeric lactic acid, the photoinitiator and the diluent are mixed uniformly according to the formula proportion, the mixing time is 20 minutes, and the mixture is stored in the dark, thereby obtaining the modified polylactic acid composite photosensitive resin for light-cured 3D printing.

[0041] 3. A 3D printing process: the modified polylactic acid composite photosensitive resin for light-cured 3D printing is put into a 3D printer for 3D printing, wherein the 3D printer is a Magic Cube Precision DLP-3D printer, the light source of the 3D printer is an ultraviolet light source with a wavelength of 540 nm, the printing speed of the 3D printer is 1 mm / s, the printing precision of the 3D printer is 0.01 mm, the printing layer thickness of the 3D printer is 0.073 mm, and the printing temperature of the 3D printer is room temperature.

[0042] Example 4

[0043] A modified polylactic acid composite photosensitive resin for light-cured 3D printing: the mass fraction of photosensitive remote chelation oligomeric lactic acid is 72.5%; the mass fraction of photoinitiator is 1.0%; the mass fraction of diluent is 26.5%. Among them, the chelation center molecule is ethylenediaminetetraacetic acid (EDTA), the vinyl grafting molecule is glycidyl methacrylate, the diluent is vinyl acetate (VA), and the photoinitiator is camphorquinone.

[0044] 1. A method for preparing photosensitive remote chelation oligomeric lactic acid, comprising the following steps:

[0045] Firstly, the chelating center molecule and L-lactic acid are added into a three-mouth round-bottom flask in a molar ratio of 1:40, and a water-carrying agent toluene is added. Then, the reaction is carried out at 90°C and 100°C for 1 hour respectively, and then the catalyst stannous octoate is added. After the circulating water vacuum pump is opened to vacuum, the reaction is carried out at 120°C and 140°C for 2 hours respectively, and then the temperature is raised to 160°C for 20 hours. Then, the temperature is lowered to 120°C, and the vinyl grafting molecule (L-lactic acid: vinyl grafting molecule = 1:5) is added, and the reaction is continued for 4 hours. Finally, the photosensitive distal chelating oligomeric lactic acid is obtained.

[0046] 2. A preparation method of a modified polylactic acid composite photosensitive resin for photocuring 3D printing, wherein the photosensitive distal chelating oligomeric lactic acid, the photoinitiator, and the diluent are uniformly mixed according to the formula proportion, the mixing time is 20 minutes, and the mixture is stored in the dark. The mixture is a modified polylactic acid composite photosensitive resin for photocuring 3D printing.

[0047] 3. A 3D printing process, wherein the modified polylactic acid composite photosensitive resin for photocuring 3D printing is placed in a 3D printer, and the 3D printing is carried out. The 3D printer is a Magic Cube Precision DLP-3D printer, the light source of the 3D printer is an ultraviolet light source with a wavelength of 540 nm, the printing speed of the 3D printer is 1 mm / s, the printing precision of the 3D printer is 0.01 mm, the printing layer thickness of the 3D printer is 0.073 mm, and the printing temperature of the 3D printer is room temperature.

[0048] Comparative Example 1

[0049] A modified polylactic acid composite photosensitive resin for photocuring 3D printing, wherein the mass fraction of the photosensitive distal chelating oligomeric lactic acid is 72.5%, the mass fraction of the photoinitiator is 1.0%, and the mass fraction of the diluent is 26.5%. The chelating center molecule is glycerol (GL), the vinyl grafting molecule is glycidyl methacrylate, the diluent is N-vinyl pyrrolidone (NVP), and the photoinitiator is IRGACURE 819.

[0050] 1. A preparation method of photosensitive distal chelating oligomeric lactic acid, comprising the following steps:

[0051] Firstly, the chelating center molecule and L-lactic acid are added into a three-mouth round-bottom flask in a molar ratio of 1:40, and a water-carrying agent toluene is added. Then, the reaction is carried out at 90°C and 100°C for 1 hour respectively, and then the catalyst stannous octoate is added. After the circulating water vacuum pump is opened to vacuum, the reaction is carried out at 120°C and 140°C for 2 hours respectively, and then the temperature is raised to 160°C for 20 hours. Then, the temperature is lowered to 120°C, and the vinyl grafting molecule (L-lactic acid: vinyl grafting molecule = 1:5) is added, and the reaction is continued for 4 hours. Finally, the photosensitive distal chelating oligomeric lactic acid is obtained.

[0052] 2. The preparation method of the modified polylactic acid composite photosensitive resin for light-curing 3D printing, wherein the photosensitive chelating oligomeric lactic acid, the photoinitiator and the diluent are uniformly mixed according to the formula proportion, the mixing time is 20 minutes, and the mixture is stored in the dark.

[0053] 3. The 3D printing process: the modified polylactic acid composite photosensitive resin for light-curing 3D printing is placed in a 3D printer for 3D printing, wherein the 3D printer is a magic cube precision DLP-3D printer, the light source of the 3D printer is an ultraviolet light source with a wavelength of 540 nm, the printing speed of the 3D printer is 1 mm / s, the printing precision of the 3D printer is 0.01 mm, the printing layer thickness of the 3D printer is 0.073 mm, and the printing temperature of the 3D printer is room temperature.

[0054] The photosensitive resin samples prepared in Examples 1-4 are prepared into samples with a length of 3 cm, a width of 1 cm and a thickness of 0.73 mm, and the tensile strength and elongation at break are tested by using a Shenzhen Sanyi electronic universal testing machine according to ASTM D638, and the results are shown in Table 1:

[0055] Table 1: Experimental results of the samples prepared in Examples 1-4

[0056] Performance Chelate center molecules M w / PDI]]> Diluents Tensile strength (MPa) Elongation at break (%) Example 1 SA 8384 / 2.32 NVP 5.98 37 Example 2 H3BTC 8444 / 2.11 NVP 9.71 42 Example 3 EDTA 9511 / 1.98 NVP 11.55 55 Example 4 EDTA 9511 / 1.78 VA 8.78 49

[0057] As can be seen from Table 1, the photosensitive resin prepared in Examples 1-4 has high tensile strength, good toughness and is easy to form, which is beneficial to the high-precision processing of the DLP printing process.

[0058] The thermal properties of Example 2, Example 3 and Comparative Example 1 are investigated, as shown in Table 2. Figure 1 As shown in Table 2, the photosensitive chelating oligomeric lactic acid obtained from Example 2 (trimesic acid) and Example 3 (ethylenediaminetetraacetic acid) has a higher melting temperature and melting enthalpy, indicating that the material has good stability and is not easy to deform, while the photosensitive chelating oligomeric lactic acid obtained from Comparative Example 1 (glycerol) has poor structural stability.

Claims

1. A modified polylactic acid composite photosensitive resin for photocuring 3D printing, characterized by, By mass fraction, comprising the following components: Photosensitive remote chelation oligomeric lactic acid 65-75%; Photoinitiator 0.5-5%; Diluent 20-30%; The photosensitive remote chelation oligomeric lactic acid is mainly L-lactic acid, which is dehydrated and polymerized with a chelating center molecule, and then end-grafted with a vinyl grafting molecule; the chelating center molecule is one of succinic acid, trimesic acid, and ethylenediaminetetraacetic acid, and the vinyl grafting molecule is glycidyl methacrylate.

2. The modified polylactic acid composite photosensitive resin for photocuring 3D printing according to claim 1, characterized by, The photoinitiator is one of IRGACURE 819, diphenyl-(2,4,6-trimethylbenzoyl) phosphine oxide, and camphorquinone. 3.The modified polylactic acid composite photoinitiating resin for light-curing 3D printing according to claim 1, characterized in that, The diluent is one of N-vinylpyrrolidone, styrene, vinylpyrrolidone, vinyl acetate, butyl acrylate, isooctyl acrylate, (methyl) acrylic acid hydroxy ester, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, neopentyl glycol diacrylate, and trimethylolpropane triacrylate. 4.The modified polylactic acid composite photoinitiator resin for 3D printing according to claim 1, characterized in that, The molar ratio of L-lactic acid to chelating center molecule is 40:1, and the molar ratio of L-lactic acid to vinyl grafting molecule is 1:

5. 5.The modified polylactic acid composite photoretin for photocuring 3D printing according to claim 1 or 4, characterized in that, The preparation process of the photosensitive remote chelation oligomeric lactic acid is as follows: L-lactic acid and chelating center molecules are added to a reactor, then toluene is added as a water-carrying agent, and the reaction is carried out at 90℃ and 100℃ for 1 hour respectively, then stannous octoate is added as a catalyst, the reactor is pumped to vacuum, and then the reaction is carried out at 120℃ and 140℃ for 2 hours respectively, then the temperature is raised to 160℃ and the reaction is carried out for 20 hours, finally the temperature is lowered to 120℃, the vinyl grafting molecule is added, and the reaction is carried out for 4 hours to obtain the photosensitive remote chelation oligomeric lactic acid.

6. The method for preparing the modified polylactic acid composite photosensitive resin for photocurable 3D printing according to any one of claims 1-5, characterized in that, Mix the components uniformly, and store in the dark.

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