Polypropylene composite material based on rare earth element modification and preparation method and application thereof

Abstract

The invention discloses a polypropylene composite material based on rare earth element modification and a preparation method and application thereof, and belongs to the technical field of medical instruments, and the polypropylene composite material comprises the following raw materials in parts by weight: 100 parts of medical grade PP, 3-8 parts of a rare earth organic complex, 5-10 parts of nano-hydroxyapatite, 2-5 parts of a maleic anhydride grafted PP compatilizer and 0.3-0.5 part of an antioxidant, the invention also provides specific preparation steps and application thereof. According to the invention, oxide + salt bimorphological rare earth and an organic ligand are complexed to form a rare earth organic complex, so that the problem of poor dispersity of inorganic rare earth is solved, and meanwhile, the material is endowed with antibacterial and antistatic functions; through a melt blending-in-situ fiber forming process, the rare earth complex forms gradient distribution in a polypropylene matrix, the surface layer is enriched with antibacterial components, and the inner layer is enhanced in mechanical property, so that a low-cost solution with high strength, antibacterial property and biocompatibility is provided for high-end medical instruments, and the market blank is filled.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and particularly to a polypropylene composite modified by rare earth elements, a preparation method thereof, and an application thereof. Background Art

[0002] Medical devices have extremely strict requirements for the performance of materials. They not only need to have good biocompatibility to prevent the induction of human immune responses but also need to have excellent mechanical properties to ensure the reliability and stability of the devices in complex usage environments.

[0003] Polypropylene is widely used in the manufacture of medical devices due to its excellent biocompatibility and processing performance. However, traditional polypropylene materials have problems such as insufficient antibacterial properties and easy bacterial growth on the surface. Especially in long-term implantation or high-frequency contact scenarios, they are prone to infection risks. They rely on chemical sterilants for periodic sterilization, and the residues of chemical sterilants are prone to cause performance deterioration such as material embrittlement and decreased transparency; repeated sterilization shortens the service life of the devices and increases medical costs; there are also defects such as environmental pollution risks in the chemical sterilization process.

[0004] In the prior art, salts and oxides of rare earth elements (such as lanthanum and cerium) have been proven to have broad-spectrum antibacterial properties due to their unique photocatalytic activity and biocompatibility. However, directly compounding them with PP easily leads to defects such as uneven dispersion, decreased mechanical properties, and easy agglomeration, resulting in unstable modification effects, and new composite technologies need to be developed.

[0005] Based on the above content, a polypropylene composite modified by rare earth elements, a preparation method thereof, and an application thereof are proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a polypropylene composite modified by rare earth elements, a preparation method thereof, and an application thereof to solve the problems in the background art.

[0007] To achieve the above purpose, the present invention provides a polypropylene composite modified by rare earth elements, which comprises the following raw materials by weight:

[0008] 100 parts of medical-grade PP, 3 - 8 parts of rare earth organic complexes, 5 - 10 parts of nano-hydroxyapatite, 2 - 5 parts of maleic anhydride grafted PP compatibilizer, 1 - 2 parts of silane coupling agent, and 0.3 - 0.5 parts of antioxidant.

[0009] Preferably, the rare earth organic complex is a compound formed by the complexation of a rare earth compound and an organic ligand.

[0010] Preferably, the rare earth compound is a mixture of several of salts and oxides of lanthanum and salts and oxides of cerium, and the organic ligand is a β-diketone compound.

[0011] Preferably, the β-diketone compound is one of acetylacetone and benzoylacetone.

[0012] The present invention provides a method for preparing the above-mentioned polypropylene composite material modified with rare earth elements, comprising the following steps:

[0013] S1. Raw material pretreatment: Prepare rare earth organic complexes and perform surface treatment on nano-hydroxyapatite;

[0014] S2. Place the rare earth organic complex, maleic anhydride grafted PP compatibilizer, and silane coupling agent in a kneader for premixing to obtain a premixed material;

[0015] S3. Add the premixed material, medical grade PP, surface-treated nano-hydroxyapatite, and antioxidant into a twin-screw extruder for extrusion granulation to obtain rare earth element-modified polypropylene composite material particles.

[0016] Preferably, the preparation steps of the rare earth organic complex are as follows:

[0017] 1) Pretreatment: Put rare earth salts and rare earth oxides with a ratio of 1:1 - 3 into a vacuum drying oven for drying, and at the same time distill the β-diketone compound;

[0018] 2) Dissolve the dried rare earth oxide and rare earth salt in absolute ethanol, stir at a speed of 150 - 250 rpm, maintain the temperature of the reaction system at 60 - 80 °C, slowly drip the β-diketone compound solution through a dropping funnel, control the dropping time within 1 - 2 h, and continue stirring and reacting for 3 - 5 h after dropping;

[0019] 3) After the reaction ends and cools to room temperature, drip deionized water under stirring conditions to precipitate the rare earth organic complex, filter and wash the precipitate using a sintered glass funnel, and then place the washed precipitate in a vacuum drying oven and dry it at 60 - 80 °C for 10 - 14 h to obtain the rare earth organic complex.

[0020] Preferably, in S2, the temperature of the kneader is controlled at 120 - 130 °C, the speed is 80 - 120 rpm, and the premixing time is 10 - 20 min.

[0021] Preferably, in S2, the silane coupling agent is one of KH550 or KH570.

[0022] Preferably, in S3, in the temperature control zones of the extruder, the temperatures from the feeding section to the head are set at 180 - 185 °C, 180 - 200 °C, 190 - 205 °C, 200 - 210 °C, 205 - 220 °C in sequence, and the screw speed is controlled at 280 - 320 rpm.

[0023] The present invention also provides an application of the above-mentioned polypropylene composite material modified with rare earth elements, which is characterized in that the polypropylene composite material modified with rare earth elements is applied to medical devices.

[0024] Preferably, during the injection molding process of medical devices using the polypropylene composite material modified with rare earth elements, nitrogen protection is adopted, and after molding, it is irradiated with γ-rays with a dose of 5-15 kGy to activate the antibacterial activity on the surface of rare earth.

[0025] Therefore, a polypropylene composite material based on rare earth element modification, its preparation method and application of the present invention have the following beneficial effects:

[0026] (1) In the present invention, a rare earth-polypropylene composite system is used. Using medical-grade PP as the matrix, rare earth oxides provide long-term physical antibacterial effects, and rare earth salts enhance the chemical bacteriostatic effect through ion release. The two work synergistically to reduce the dependence of medical devices on chemical sterilization.

[0027] (2) In the preparation process of the present invention, first, rare earth elements are complexed with organic ligands to form rare earth organic complexes, which solves the problem of poor dispersion of inorganic rare earths and endows the material with antibacterial and antistatic functions at the same time; then, through the melt blending-in-situ fibrillation process, the rare earth organic complexes form a gradient distribution in the polypropylene matrix, with antibacterial components enriched on the surface layer and mechanical properties enhanced in the inner layer; secondly, in the premixing stage, the silane coupling agent can undergo a chemical reaction on the surface of the rare earth complex to form a chemical bond, thereby improving the compatibility and interfacial bonding properties of the rare earth complex with other materials. At the same time, acting together with the compatibilizer, it can better improve the dispersion uniformity of the rare earth complex in the matrix and enhance the comprehensive performance of the material.

[0028] (3) The composite material prepared by the present invention is applied to medical devices, and its antibacterial rate against common pathogenic bacteria such as Escherichia coli and Staphylococcus aureus is >99% (GB / T31402-2015), reducing the formation of biofilms on the surface of the device; its cytotoxicity ≤ Grade 1 (ISO 10993-5), meeting the requirements for long-term implantation.

[0029] Next, through examples, the technical solutions of the present invention will be further described in detail. Specific embodiments

[0030] The following further illustrates the technical solutions of the present invention through examples.

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.

[0032] Example 1

[0033] In this example, a rare earth element-modified polypropylene composite material was prepared and applied to syringe production to improve the antibacterial performance of the syringe. The specific steps are as follows:

[0034] S1. First, synthesize rare earth organic complexes, specifically:

[0035] 1) Mix lanthanum oxide, cerium oxide, and ammonium cerium citrate in a mass ratio of 1:2:1, and place them in a vacuum drying oven. Dry at 90 °C for 10 h to remove crystal water and adsorbed water, obtaining a mixed rare earth compound;

[0036] 2) Dissolve the dried mixed rare earth compound in absolute ethanol, transfer it to a three-necked flask equipped with a stirrer, a thermometer, and a dropping funnel. Start the stirring device, set the stirring speed to 200 rpm, and maintain the temperature of the reaction system at 70 °C. Slowly add the acetylacetone solution through the dropping funnel, and the dropping process lasts for 1.5 h. After the dropping is completed, continue stirring and reacting for 4 h to ensure that the rare earth ions and the organic ligands are fully complexed.

[0037] 3) After the reaction is completed and cooled to room temperature, slowly add deionized water dropwise under stirring to precipitate the rare earth organic complex. Filter with a sintered glass funnel, wash the precipitate 3 times with absolute ethanol, and then dry it in a vacuum drying oven at 70 °C for 12 h to obtain the rare earth organic complex.

[0038] S2. Add 5 parts of the rare earth organic complex prepared in S1, 3 parts of maleic anhydride grafted PP compatibilizer, and 1 part of silane coupling agent KH550 to a mixer. Premix at 130 °C and 100 rpm for 15 min to obtain a premix.

[0039] S3. Take nano-hydroxyapatite, add 3% of its mass of stearic acid, and stir at 80 °C for 30 min in a high-speed mixer to uniformly coat the stearic acid on the surface of the nano-hydroxyapatite and improve its dispersibility in the polypropylene matrix;

[0040] Then add the premix, 100 parts of medical-grade PP, 6 parts of surface-treated nano-hydroxyapatite, and 0.3 part of antioxidant 1010 to a twin-screw extruder. The temperature of the extruder from the feeding section to the die head is set to 180 °C, 190 °C, 200 °C, 210 °C, and 220 °C in sequence, and the screw speed is 300 rpm for extrusion granulation to obtain a rare earth element-modified polypropylene composite material.

[0041] S4. Syringe injection molding: Put the granulated composite material into an injection molding machine, set the barrel temperature at 190 - 210 °C, the mold temperature at 30 - 50 °C, the injection pressure at 80 - 120 MPa, and the holding pressure time at 10 - 20 s. At the same time, add nitrogen for assisted injection molding to produce the finished syringe;

[0042] Place the finished syringe in a γ-ray irradiation device and process it with an irradiation dose of 10 kGy to activate the antibacterial activity on the surface of rare earth.

[0043] Example 2

[0044] The raw materials by weight are as follows:

[0045] 100 parts of medical-grade PP, 3 parts of rare earth organic complex, 2 parts of maleic anhydride-grafted PP compatibilizer, 1 part of silane coupling agent KH550, 5 parts of nano-hydroxyapatite, 0.4 part of antioxidant 1010;

[0046] The raw materials for synthesizing the rare earth organic complex are lanthanum oxide and cerium chloride with a mass ratio of 1:1; under other unchanged conditions, produce the finished syringe according to the steps in Example 1.

[0047] Example 3

[0048] The raw materials by weight are as follows:

[0049] 100 parts of medical-grade PP, 8 parts of rare earth organic complex, 5 parts of maleic anhydride-grafted PP compatibilizer, 2 parts of silane coupling agent KH550, 10 parts of nano-hydroxyapatite, 0.5 part of antioxidant 1010;

[0050] The raw materials for synthesizing the rare earth organic complex are lanthanum oxide, lanthanum oxide and cerium chloride with a mass ratio of 1:1:1; under other unchanged conditions, prepare the finished syringe according to the steps in Example 1.

[0051] Comparative Example 1

[0052] This Comparative Example 1 is the same as the steps in the Example, only modifying the raw materials for synthesizing the rare earth organic complex to lanthanum oxide, cerium oxide and ammonium cerium citrate with a mass ratio of 1:1:4.

[0053] Comparative Example 2

[0054] This comparative example is the same as the steps in Example 2, only modifying the raw materials for synthesizing the rare earth organic complex to lanthanum oxide and cerium chloride with a mass ratio of 4:1.

[0055] Comparative Example 3

[0056] This comparative example is the same as the steps in Example 1, only removing the final γ-ray irradiation operation.

[0057] Comparative Example 4

[0058] This comparative example is the same as the steps in Example 1, except that the irradiation dose of the final γ-ray irradiation operation is modified to 30 kGy.

[0059] Comparative Example 5

[0060] This comparative example is the same as the steps in Example 1, except that the temperatures of the extruder from the feeding section to the head are sequentially modified to 150 °C, 160 °C, 170 °C, 180 °C, 190 °C, and the screw speed is 200 rpm.

[0061] Comparative Example 6

[0062] This comparative example is the same as the steps in Example 1, except that the temperatures of the extruder from the feeding section to the head are sequentially modified to 200 °C, 210 °C, 220 °C, 230 °C, 240 °C, and the rotation speed is 450 rpm.

[0063] Antibacterial tests were carried out on the products of the above examples and comparative examples, and the antibacterial rate results are shown in Table 1 below:

[0064] Table 1 Antibacterial rate results

[0065] Sample Inhibitory rate against Escherichia coli Inhibitory rate against Staphylococcus aureus Example 1 99.6％ 99.8％ Example 2 99.3％ 99.6％ Example 3 99.5％ 99.2％ Comparative example 1 85.6％ 83.2％ Comparative example 2 88.4％ 86.2％ Comparative example 3 92.3％ 93.4％ Comparative example 4 89.3％ 88.9％ Comparative example 5 95.3％ 95.6％ Comparative example 6 97.1％ 97.4％

[0066] It can be seen from Table 1 above that when preparing rare earth organic ligands, when the mass ratio of rare earth salts to rare earth oxides in Examples 1-3 is controlled within the range of 1:1 to 3, the obtained composite injection molded products have better antibacterial performance. When the ratio exceeds this range, such as in Comparative Examples 1 and 2, the antibacterial performance decreases, indicating that the products prepared by the protected solution of the present invention have a 24-hour antibacterial rate of ≥ 99% against common pathogenic bacteria such as Escherichia coli and Staphylococcus aureus, and can reduce the formation of biofilms on the surface of medical devices, meeting the antibacterial performance requirements of medical syringes.

[0067] By comparing Example 1 with Comparative Examples 3 and 4, in Comparative Example 3, due to the absence of γ-ray irradiation operation, its antibacterial rate decreased compared with Example 1, because γ-ray irradiation activated the antibacterial activity on the surface of rare earths, enhancing its antibacterial performance. In Comparative Example 4, due to excessive irradiation dosage, it caused excessive damage to the material properties and antibacterial components, resulting in a decrease in the antibacterial rate.

[0068] By comparing Example 1, Comparative Example 5 and Comparative Example 6, the stage temperature of the temperature control zone of the extruder in Comparative Example 5 was lower than that in Example 1, and the rotation speed decreased, resulting in a decrease in the final antibacterial rate. The reason is that too low temperature may lead to poor melting effect of raw materials such as polypropylene resin, rare earth organic complex, and nano-hydroxyapatite, and the dispersion of the antibacterial agent may also be uneven, resulting in a decrease in antibacterial performance. In Comparative Example 6, the temperature of the temperature control zone of the extruder was higher than that in Example 1, and its final antibacterial rate decreased. This is because too high temperature may also affect the stability of the rare earth organic complex, thereby affecting antibacterial performance and biocompatibility, etc.

[0069] The mechanical properties of the above Examples 1-3, Comparative Examples 5 and 6 were tested. Pure PP was used as the control group. The tensile strength was tested with reference to ASTM D638 standard, and the flexural modulus was tested with reference to ASTM D790 standard. The results are shown in Table 2 below.

[0070] Table 2 Test Results of Mechanical Properties

[0071]

[0072]

[0073] As can be seen from Table 2, compared with pure PP, the product prepared by the present invention has an increase of more than 35% in tensile strength and more than 40% in flexural modulus. In Comparative Example 5, the stage temperature of the temperature control zone of the extruder was lower than that in Example 1, and its tensile strength and flexural modulus also decreased correspondingly. The reason is that too low temperature may lead to poor melting effect of raw materials such as polypropylene resin, rare earth organic complex, and nano-hydroxyapatite, and uneven mixing, thus reducing the mechanical properties of the material. In Comparative Example 6, the temperature of the temperature control zone of the extruder was higher than that in Example 1, and its tensile strength and flexural modulus also decreased correspondingly. This is because too high temperature and rotation speed may cause the degradation of polypropylene resin, resulting in poor mechanical properties of the material. Moreover, too high rotation speed may cause particles such as nano-hydroxyapatite to be too evenly distributed in the material, which is not conducive to forming an effective reinforcing structure and will also affect the mechanical properties.

[0074] Through comparison, it can be seen that in the temperature control zone of the extruder, the temperatures from the feeding section to the die head are set as 180 - 185°C, 180 - 200°C, 190 - 205°C, 200 - 210°C, and 205 - 220°C in sequence, that is, the temperature of the temperature control zone of the extruder is set at 180 - 220°C. This temperature range can make the polymer matrix in the system reach a suitable viscous flow state. In this state, the activity of the polymer molecular chains is enhanced, which is beneficial to the orientation and arrangement of the molecular chains. For in-situ fibrillation, at a specific temperature, the dispersed phase is stretched into a fibrous shape under the action of the flow field of the continuous phase, and the temperature ensures that the dispersed phase has sufficient fluidity to deform and form a fiber structure. By forming a temperature gradient through different temperature control regions, this temperature difference will cause the physical state and the degree of molecular chain movement of the material in different regions to be different. For example, in the region with a higher temperature, the activity of the molecular chains is stronger, and the dispersed phase is more easily stretched into fibers; while in the region with a lower temperature, the movement of the molecular chains is relatively restricted, which is beneficial to fixing the already formed fiber structure and microscopic morphology, thus forming a gradient structure.

[0075] At the same time, in the embodiment, the screw speed is set at 300 rpm. A higher speed will generate strong shear force and tensile force. Under the action of the shear force, the dispersed phase particles are continuously stretched and refined, promoting the formation of a fibrous structure and realizing in-situ fibrillation. At the same time, the rotation of the screw makes the material form a complex flow field in the extruder, and the degrees of shear and tensile action received by the material at different positions are different, thereby making the rare earth organic complex form a gradient distribution in the polypropylene matrix.

[0076] Carry out cytotoxicity tests on the products of the above Examples 1 - 3 according to the ISO 10993 - 5 standard. The cytotoxicity ratings of all groups are ≤ Grade 1, indicating good biocompatibility and meeting the requirements for long-term implantation.

[0077] Test the syringe in Example 1. Under normal use conditions, the instrument can withstand ≥ 5 cycles of moist heat sterilization (121°C / 30 min) without loss of mechanical properties; compared with the unmodified polypropylene instrument, the service life is increased by 2 - 3 times (verified by ISO10993 biocompatibility test), the cost of instrument loss per single medical process is reduced by 40 - 60%, and the procurement and handling costs of chemical sterilants are avoided.

[0078] The above embodiments show that when the composite material is applied to disposable syringes, it has excellent properties such as good biocompatibility, chemical stability, and excellent mechanical properties. Therefore, in some embodiments, it can also be used in infusion sets, pharmaceutical packaging materials, and connectors for various pipelines in the operating room.

[0079] Among them, medical-grade PP and rare-earth organic complexes have good biocompatibility, which can reduce the irritation and adverse reactions to human tissues; nano-hydroxyapatite is similar to the main components of human bones and teeth, and has excellent bioactivity and compatibility, which can reduce the risk of immune reactions caused by materials in the body; rare-earth organic complexes help improve the affinity of the overall material with biological tissues. At the same time, medical-grade PP provides basic strength and toughness, enabling the composite material to withstand a certain amount of external force without deformation or rupture; the addition of nano-hydroxyapatite can enhance the hardness and rigidity of the composite material, improve its wear resistance, and make it more suitable for use in operating room pipeline connectors that need to withstand a certain amount of pressure and friction. The maleic anhydride grafted PP compatibilizer improves the interfacial bonding between different components, makes the mechanical properties of the composite material more stable and uniform, and reduces the damage caused by stress concentration.

[0080] In addition, medical-grade PP and maleic anhydride grafted PP have good chemical stability, can resist the erosion of chemical substances such as infusion drugs and disinfectants, and are not prone to chemical reactions that affect the performance of the material and the quality of the drug. The addition of antioxidants can effectively inhibit the oxidation reaction of the composite material during use, delay the aging speed of the material, and extend its service life. This is very important for operating room pipeline connectors used for a long time, as well as drug packaging materials and infusion sets that may be stored for a long time, and can ensure the stable performance of the material within the validity period.

[0081] Rare-earth organic complexes may endow the composite material with some special functions, such as fluorescence characteristics, etc., which can be used for the marking, tracking and monitoring of drug packaging materials or the infusion process, and help improve the safety and traceability of the medical process.

[0082] Therefore, the polypropylene composite material modified based on rare-earth elements, its preparation method and application of the present invention use "oxide + salt" dual-form rare earths complexed with organic ligands to form rare-earth organic complexes, solve the problem of poor dispersion of inorganic rare earths, and at the same time endow the material with antibacterial and antistatic functions; subsequently, through the melt blending-in-situ fibrillation process, the rare-earth complexes form a gradient distribution in the polypropylene matrix, with antibacterial components enriched on the surface layer and mechanical properties enhanced on the inner layer, providing a low-cost solution with high strength, antibacterial property and biocompatibility for high-end medical devices, filling the market gap.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A polypropylene composite modified with rare earth elements, characterized in that, It comprises the following raw materials by weight parts: 100 parts of medical-grade PP, 3 - 8 parts of rare earth organic complex, 5 - 10 parts of nano-hydroxyapatite, 2 - 5 parts of maleic anhydride grafted PP compatibilizer, 1 - 2 parts of silane coupling agent and 0.3 - 0.5 part of antioxidant.

2. The polypropylene composite material modified by rare earth elements according to claim 1, characterized in that: The rare earth organic complex is a compound formed by the complexation of a rare earth compound and an organic ligand.

3. The polypropylene composite material modified by rare earth elements according to claim 2, wherein: The rare earth compound is a mixture of several of salts and oxides of lanthanum and salts and oxides of cerium, and the organic ligand is a β-diketone compound.

4. A preparation method of a rare earth element-modified polypropylene composite material according to any one of claims 1-3, characterized in that, It includes the following steps: S1. Raw material pretreatment: Prepare the rare earth organic complex and perform surface treatment on the nano-hydroxyapatite. S2. Place the rare earth organic complex, maleic anhydride grafted PP compatibilizer, and silane coupling agent in a kneader for premixing to obtain a premix. S3. Add the premix, medical-grade PP, surface-treated nano-hydroxyapatite, and antioxidant together into a twin-screw extruder for extrusion granulation to obtain rare earth element-modified polypropylene composite particles.

5. The preparation method of a polypropylene composite material modified by rare earth elements according to claim 4, characterized in that, The preparation steps of the rare earth organic complex are as follows: 1) Pretreatment: Put rare earth salts and rare earth oxides in a ratio of 1 - 3:1 into a vacuum drying oven for drying, and at the same time distill the β-diketone compound. 2) Dissolve the dried rare earth oxide and rare earth salt in absolute ethanol, stir at a speed of 150 - 250 rpm, maintain the temperature of the reaction system at 60 - 80 °C, slowly drip the β-diketone compound solution through a dropping funnel, control the dropping time within 1 - 2 h, and after the dropping is completed, continue to stir and react for 3 - 5 h. 3) After the reaction ends and cools to room temperature, drip deionized water under stirring conditions to precipitate the rare earth organic complex. Use a sintered glass funnel to filter and wash the precipitate, and then place the washed precipitate in a vacuum drying oven and dry it at 60 - 80 °C for 10 - 14 h to obtain the rare earth organic complex.

6. The preparation method of a polypropylene composite material modified by rare earth elements according to claim 4, characterized in that: In S2, the temperature of the kneader is controlled at 120 - 130 °C, the rotation speed is 80 - 120 rpm, and the premixing time is 10 - 20 min.

7. The preparation method of a polypropylene composite material modified by rare earth elements according to claim 4, characterized in that: In S2, the silane coupling agent is one of KH550 or KH570.

8. The preparation method of a polypropylene composite material modified by rare earth elements according to claim 4, characterized in that: In S3, in the temperature control zones of the extruder, the temperatures from the feeding section to the head are set as 170 - 190 °C, 180 - 200 °C, 190 - 210 °C, 200 - 220 °C, 210 - 230 °C in sequence, and the screw rotation speed is controlled at 280 - 320 rpm.

9. Use of a polypropylene composite material modified with rare earth elements as described in any one of claims 1 - 3, characterized in that: Apply the rare earth element-modified polypropylene composite to medical devices.

10. The application of a rare earth element-modified polypropylene composite material according to claim 9, characterized in that: During the injection molding of medical devices using the rare earth element-modified polypropylene composite, nitrogen protection is adopted, and after molding, it is irradiated with γ-rays at a dose of 5 - 15 kGy to activate the antibacterial activity on the surface of the rare earth.

Images