A polycaprolactone magnesium salt composite 3D printing wire and its preparation method

Abstract

This invention discloses a polycaprolactone magnesium salt composite 3D printing filament and its preparation method. The filament comprises the following components by mass: 65%-95% pure PCL, 4%-30% magnesium salt powder, and 0.1%-5% polycaprolactone good solvent. By employing key technical measures, including surface treatment of the magnesium salt powder using a polycaprolactone good solvent, a premixed slurry side-feeding process, and integrated kneading and mixing, the invention effectively addresses the problems of poor compatibility and low finished product yield of PCL-magnesium salt composite 3D printing materials.

Description

Technical Field

[0001] The present invention belongs to the field of polymer materials, and in particular relates to a polycaprolactone magnesium salt composite 3D printing wire and a preparation method thereof. Background Art

[0002] In recent years, 3D printing technology has been widely used in industries such as industry and medicine. Tissue repair in medical applications, in particular, requires the preparation of highly customized devices tailored to specific conditions, making it a highly suitable application for 3D printing. Magnesium-based salt materials, as a key material for bone repair, have garnered significant attention within the field. Several studies have reported on the 3D printing and application of magnesium-based salt materials, such as Chinese invention application CN110680953B, "A method for preparing porous bone repair scaffolds with different magnesium phosphate phases based on 3D printing technology." However, the primary technical approach used in such research is powder sintering printing, which requires expensive and immature equipment and techniques.

[0003] 3D printing technologies include fused deposition modeling (FDM) and powder sintering. FDM offers advantages such as simple operation, low equipment costs, and easily replaceable consumables. With the development of FDM technology, polymer-inorganic salt composite filaments have also matured. FDM printing of polymer and inorganic salt composites can, in some cases, replace powder sintering printing methods that require high equipment costs and high performance materials. Therefore, the preparation of magnesium-based salt polymer composite filaments for use in 3D printing of bone repair has become a readily conceivable technical approach.

[0004] However, so far, reports on this type of technical solution are still very rare. This is because the density, mechanical properties, etc. of polymer materials and inorganic salt powders are quite different, and their compatibility during blending and granulation is poor; the addition of inorganic salt powders will affect the viscosity of the polymer matrix material when it is melted, thereby affecting the diameter control and surface roughness of the 3D printing wire; in addition, inorganic salts are generally easy to absorb water and become damp, which will also seriously affect the processing of degradable polymer melts.

[0005] Polycaprolactone (PCL) is an environmentally friendly and biomaterial that has good compatibility with biological cells and can be degraded into CO2 and H2O. Compared with the mainstream degradable 3D printing material polylactic acid, polycaprolactone has degradation products that are less acidic, milder to biological tissues, and has relatively low glass transition temperature (-60°C) and melting point (60°C-63°C), making it easy to form at low temperatures and other excellent properties that are more suitable for use in in vivo implantable devices. Therefore, PCL is compounded with magnesium-based materials for use in bone repair, bone tissue engineering and other fields, which has also been a research hotspot in recent years. For example, U.S. Patent US 2019 / 0024244 Al reported a technology for double-layer coating of magnesium alloy plates with magnesium fluoride and PCL. Compared with samples coated with a single layer of magnesium fluoride or uncoated magnesium samples, the corrosion resistance is improved, and it has excellent cell viability, cell adhesion and cell proliferation. However, polycaprolactone is a soft material, making it more difficult to use in FDM printing. The molding process requirements for its filament preparation are also higher. It is even more difficult to further add inorganic salt powder and other ingredients to prepare polymer-inorganic salt composite filaments. Therefore, PCL-magnesium-based salt composite 3D printing materials have not been reported. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art by adopting key technical means such as surface treatment of magnesium-based salt powder using a good solvent of polycaprolactone, side feeding process of premixed slurry, and integrated kneading and mixing to effectively solve the problems of poor compatibility of PCL-magnesium-based salt composite 3D printing materials and low finished product yield.

[0007] To achieve the above-mentioned purpose of the invention, in a first aspect, the present invention provides a polycaprolactone magnesium-based salt composite 3D printing wire, comprising the following mass components: 65%-95% PCL pure material, 4%-30% magnesium-based salt powder, and 0.1%-5% polycaprolactone good solvent.

[0008] In the above-mentioned polycaprolactone magnesium-based salt composite 3D printing wire, the magnesium-based salt is one or more of all salts containing magnesium ions such as magnesium carbonate, magnesium chloride, magnesium phosphate, magnesium sulfate, magnesium nitrate, and calcium magnesium carbonate, and its powder particle size ranges from 0.2 μm to 500 μm.

[0009] In a second aspect, the present invention also provides a method for preparing a polycaprolactone magnesium-based salt composite 3D printing wire, comprising the following steps: (1) weighing the following mass components respectively: 65%-95% of PCL pure material, 4%-30% of magnesium-based salt powder, and 0.1%-5% of polycaprolactone good solvent, wherein the PCL pure material is divided into three parts; (2) adding the good solvent of polycaprolactone to the magnesium-based salt powder, mixing and stirring to form a slurry; (3) mixing the first part of the PCL pure material with the magnesium-based salt powder described in step (2); The powder slurry is mixed and then enters the side feeding system of the twin-screw extruder. The second part of PCL pure material enters from the main feeding system of the twin-screw extruder and is extruded into a melt; (4) After the melt is extruded by the extruder, an integrated kneading mixer is used to further knead and mix the melt so that the magnesium alloy powder is evenly distributed in the melt, and then granulated to obtain a composite masterbatch; (5) After the composite masterbatch is dried, it is blended with the third part of PCL pure material and a PCL-magnesium-based salt composite 3D printing filament is obtained by single-screw extrusion.

[0010] In the above-mentioned method for preparing a polycaprolactone magnesium salt composite 3D printing wire, the good solvent for polycaprolactone used in step (2) is one or more polar solvents such as toluene, tetrahydrofuran, ethyl acetate, dichloromethane, chloroform, dimethyl sulfoxide, dimethylformamide, hexafluoroisopropanol, etc.

[0011] In the above-mentioned method for preparing a polycaprolactone magnesium salt composite 3D printing wire, the specific process of preparing the slurry in step (2) is: placing the raw materials in a high-speed mixer and fully stirring and mixing for 2 minutes to 5 minutes.

[0012] In the above-mentioned method for preparing a polycaprolactone magnesium salt composite 3D printing wire, the twin-screw extrusion processing temperature in step (3) is 80°C-135°C.

[0013] In the above-mentioned method for preparing a polycaprolactone magnesium salt composite 3D printing wire, the single-screw extrusion processing temperature in step (5) is 80°C-135°C.

[0014] In the above-mentioned method for preparing a polycaprolactone magnesium salt composite 3D printing filament, the PCL pure material is added in three parts at the main feed of the twin-screw extruder, the side feed of the twin-screw extruder, and the main feed of the single-screw extruder.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] Pre-treating the magnesium-based salt powder with a good solvent of polycaprolactone can prevent the magnesium-based salt powder from absorbing water and moisture while improving the compatibility between the powder and the PCL material; adopting a solution of feeding the slurry and part of the PCL pure material into the side can not only prevent the slurry from bridging and clogging at the main feeding port, but also effectively improve the dispersion of the magnesium-based salt powder in PCL, thereby solving the problems of poor dispersion, poor mechanical properties, and low product yield of the composite material. DETAILED DESCRIPTION

[0017] The present invention will now be further described in detail with reference to the following embodiments. The application of the present invention is not limited to the following embodiments, and any modifications made to the present invention will fall within the scope of protection of the present invention.

[0018] Example 1:

[0019] A polycaprolactone magnesium carbonate composite 3D printing filament comprises the following components by mass: 70% PCL, 28% magnesium carbonate powder, and 2% dichloromethane.

[0020] The particle size range of magnesium carbonate powder is 200±20μm.

[0021] Preparation steps: (1) Blend 2 parts of dichloromethane with 28 parts of magnesium carbonate powder, place them in a high-speed mixer, and stir them thoroughly for 2 to 5 minutes to form a slurry; (2) Mix 20 parts of PCL pure material and magnesium carbonate powder slurry in corresponding parts to prepare a side feed; (3) Extrude the side feed into a melt with 20 parts of PCL pure material through the side feeding system of a twin-screw extruder, and the processing temperature is 135°C; (4) After the melt is extruded by the extruder, an integrated kneading mixer is used to further knead and mix the melt so that the magnesium alloy powder is evenly distributed in the melt, and then granulate to obtain a composite masterbatch; (5) After the composite masterbatch is dried, it is blended with 30 parts of PCL pure material and extruded into a composite 3D printing filament through a single screw extruder, and the processing temperature is 135°C.

[0022] The total PCL content of the above-mentioned filament is 70%. After testing, the filament is smooth, with a diameter of 1.75±0.02mm, and a texture similar to that of inorganic materials. The printing effect is good, and the measured yield rate of printed parts is >95%.

[0023] The obtained material was 3D printed into standard specimens, and the tensile performance test (GB

[0031] T1040.2-2006), flexural strength (GB / T1446-2006), and impact performance test (GB / T1943-2008) were carried out respectively. The test results are shown in Table 1.

[0024] Example 2:

[0025] A polycaprolactone magnesium phosphate composite 3D printing filament comprises the following components by mass: 65% PCL, 30% magnesium phosphate powder, and 5% chloroform.

[0026] The particle size range of magnesium phosphate powder is 1±0.2μm.

[0027] Preparation steps: (1) Blend 2 parts of chloroform with 28 parts of magnesium phosphate powder, place them in a high-speed mixer, and stir them thoroughly for 2 to 5 minutes to form a slurry; (2) Mix 20 parts of PCL pure material and magnesium phosphate powder slurry in corresponding parts to prepare a side feed; (3) Extrude the side feed into a melt with 20 parts of PCL pure material through the side feeding system of a twin-screw extruder, and the processing temperature is 135°C; (4) After the melt is extruded by the extruder, an integrated kneading mixer is used to further knead and mix the melt so that the magnesium alloy powder is evenly distributed in the melt, and then granulate to obtain a composite masterbatch; (5) After the composite masterbatch is dried, it is blended with 25 parts of PCL pure material and extruded into a composite 3D printing filament by a single screw extruder, and the processing temperature is 135°C.

[0028] The total PCL content of the above-mentioned filament is 65%. After testing, the filament is smooth, with a diameter of 1.75±0.02mm, and a texture similar to that of inorganic materials. The printing effect is good, and the measured yield rate of printed parts is >95%.

[0029] The obtained material was 3D printed into standard specimens, and the tensile performance test (GB

[0031] T1040.2-2006), flexural strength (GB / T1446-2006), and impact performance test (GB / T1943-2008) were carried out respectively. The test results are shown in Table 1.

[0030] Example 3:

[0031] A polycaprolactone magnesium sulfate composite 3D printing filament comprises the following components by mass: PCL 95%, magnesium sulfate powder 4%, and dimethylformamide 1%.

[0032] The particle size range of magnesium sulfate powder is 100±10μm.

[0033] Preparation steps: (1) Blend 2 parts of dimethylformamide with 28 parts of magnesium sulfate powder, place them in a high-speed mixer, and stir them thoroughly for 2 to 5 minutes to form a slurry; (2) Mix 30 parts of PCL pure material and magnesium sulfate powder slurry in corresponding parts to prepare a side feed; (3) Extrude the side feed into a melt with 30 parts of PCL pure material through the side feeding system of a twin-screw extruder, and the processing temperature is 135°C; (4) After the melt is extruded by the extruder, an integrated kneading mixer is used to further knead and mix the melt so that the magnesium alloy powder is evenly distributed in the melt, and then granulate to obtain a composite masterbatch; (5) After the composite masterbatch is dried, it is blended with 35 parts of PCL pure material and extruded into a composite 3D printing filament by a single screw extruder, and the processing temperature is 135°C.

[0034] The total PCL content of the above-mentioned filament is 95%. After testing, the filament is smooth, with a diameter of 1.75±0.02mm, and a texture similar to that of inorganic materials. The printing effect is good, and the measured yield rate of printed parts is >95%.

[0035] The obtained material was 3D printed into standard specimens, and the tensile performance test (GB

[0031] T1040.2-2006), flexural strength (GB / T1446-2006), and impact performance test (GB / T1943-2008) were carried out respectively. The test results are shown in Table 1.

[0036] Example 4:

[0037] A polycaprolactone calcium magnesium carbonate composite 3D printing filament comprises the following components by mass: 80% PCL, 15% calcium magnesium carbonate powder, and 5% tetrahydrofuran.

[0038] The particle size range of calcium magnesium carbonate powder is 20±2μm.

[0039] Preparation steps: (1) Blend 5 parts of tetrahydrofuran with 15 parts of calcium magnesium carbonate powder, place them in a high-speed mixer, and stir them thoroughly for 2 to 5 minutes to form a slurry; (2) Mix 25 parts of PCL pure material and calcium magnesium carbonate powder slurry in corresponding parts to prepare a side feed; (3) Extrude the side feed into a melt with 25 parts of PCL pure material through the side feeding system of a twin-screw extruder, and the processing temperature is 135°C; (4) After the melt is extruded by the extruder, an integrated kneading mixer is used to further knead and mix the melt so that the magnesium alloy powder is evenly distributed in the melt, and then granulate to obtain a composite masterbatch; (5) After the composite masterbatch is dried, it is blended with 30 parts of PCL pure material and extruded into a composite 3D printing filament through a single screw extruder, and the processing temperature is 135°C.

[0040] The total PCL content of the above-mentioned filament is 80%. After testing, the filament is smooth, with a diameter of 1.75±0.02mm, and a texture similar to that of inorganic materials. The printing effect is good, and the measured yield rate of printed parts is >95%.

[0041] The obtained material was 3D printed into standard specimens, and the tensile performance test (GB

[0031] T1040.2-2006), flexural strength (GB / T1446-2006), and impact performance test (GB / T1943-2008) were carried out respectively. The test results are shown in Table 1.

[0042] Comparative Example 1: In comparison, the performance of the 3D printing filament prepared from pure PCL material is inferior to that of the solution of the present invention. The same single-screw extrusion process as the above embodiment is used, and the processing temperature is 135°C to prepare pure PCL 3D printing filament. The comparison of its various performance indicators is shown in Table 1.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

[0044] Table 1. Performance test results of polycaprolactone magnesium salt composite materials

[0045]

Claims

1. A polycaprolactone magnesium salt composite 3D printing filament, characterized in that: The invention comprises the following components by mass: 65%-95% PCL pure material, 4%-30% magnesium-based salt powder, and 0.1%-5% polycaprolactone good solvent; the magnesium-based salt is one or more of magnesium carbonate, magnesium phosphate, magnesium sulfate, magnesium nitrate, and calcium magnesium carbonate, and the powder particle size ranges from 0.2 μm to 500 μm; The preparation method of the polycaprolactone magnesium-based salt composite 3D printing wire comprises the following steps: (1) weighing the following mass components respectively: 65%-95% of PCL pure material, 4%-30% of magnesium-based salt powder, and 0.1%-5% of polycaprolactone good solvent, wherein the PCL pure material is divided into three parts; (2) Add the good solvent of polycaprolactone to the magnesium-based salt powder, mix and stir to form a slurry, place the raw materials in a high-speed mixer, and stir and mix thoroughly for 2 minutes to 5 minutes; (3) The first part of PCL pure material is mixed with the magnesium-based salt powder slurry in step (2), and then enters the side feeding system of the twin-screw extruder. The second part of PCL pure material enters the main feeding system of the twin-screw extruder and is extruded into a melt. The twin-screw extrusion processing temperature is 80℃-135℃; (4) After the melt is extruded by the extruder, an integrated kneading mixer is used to further knead and mix the melt so that the magnesium-based salt powder is evenly distributed in the melt, and then granulation is performed to obtain a composite masterbatch; (5) After the composite masterbatch is dried, it is blended with the third part of PCL pure material, and the PCL-magnesium-based salt composite 3D printing filament is obtained by single-screw extrusion. The single-screw extrusion processing temperature is 80℃-135℃; The PCL pure material is added in three parts at the main feed of the twin-screw extruder, the side feed of the twin-screw extruder, and the main feed of the single-screw extruder; The good solvent for polycaprolactone used in step (2) is one or more of tetrahydrofuran, ethyl acetate, dichloromethane, chloroform, dimethyl sulfoxide, dimethylformamide, and hexafluoroisopropanol polar solvents.

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