A waterproof and antibacterial pharmaceutical polypropylene bottle cap and its preparation method

Abstract

The present application discloses a waterproof and antibacterial pharmaceutical polypropylene bottle cap and a preparation method thereof. The raw materials of the bottle cap include masterbatch and polypropylene; the raw materials of the masterbatch include 45-50% modified titanium dioxide, 1.5-4.7% dispersant, and the balance is carrier resin; the preparation method of the modified titanium dioxide is as follows: S1. Mix and stir an amino silane coupling agent and titanium dioxide in a short-chain alcohol to obtain amino-modified titanium dioxide; S2. Add the amino-modified titanium dioxide to a cysteine solution for amidation reaction to obtain amidated titanium dioxide; S3. Add the amidated titanium dioxide to a zinc ion solution, stir evenly, then add a cysteine solution, stir for coordination assembly, and after the reaction is completed, filter, wash with water, and dry to obtain. Through a specific modification method, the present application induces the formation of needle-like nanostructures of MOF crystals on the surface of titanium dioxide, achieving an efficient and durable antibacterial effect.

Description

Technical Field

[0001] This application relates to the field of polypropylene containers, and particularly to a waterproof and antibacterial pharmaceutical polypropylene bottle cap and its preparation method. Background Art

[0002] As an important part of pharmaceutical packaging, the design and material selection of bottle caps are crucial for protecting drugs from external contamination. As a common thermoplastic, polypropylene has been widely used in pharmaceutical packaging auxiliaries due to its good mechanical strength, chemical corrosion resistance, high thermal stability, and waterproof sealing performance.

[0003] During actual use, when patients or medical staff open the bottle cap to take medicine, the surface and inner wall of the bottle cap are extremely vulnerable to microbial contamination from hands and the surrounding environment. Although some existing polypropylene bottle cap products have improved their antibacterial performance by adding antibacterial agents, etc., after long-term use, the antibacterial effect often gradually weakens or even fails, and the durability performance is not good. Summary of the Invention

[0004] To solve the problem that the current polypropylene bottle caps have poor long-term antibacterial performance, this application provides a waterproof and antibacterial pharmaceutical polypropylene bottle cap and its preparation method.

[0005] In the first aspect, this application provides a waterproof and antibacterial pharmaceutical polypropylene bottle cap, the raw materials of which contain 1.5 - 4.7wt% masterbatch, and the balance is polypropylene; the raw materials of the masterbatch include 45 - 50wt% modified titanium dioxide, 3 - 5wt% dispersant, and the balance is carrier resin;

[0006] The preparation method of the modified titanium dioxide is as follows:

[0007] S1. Mix and stir an amino silane coupling agent and titanium dioxide in a short-chain alcohol to obtain amino-modified titanium dioxide;

[0008] S2. Add the amino-modified titanium dioxide into a cysteine solution for amidation reaction to obtain amidated titanium dioxide;

[0009] S3. Add the amidated titanium dioxide into a zinc ion solution, stir evenly, then add a cysteine solution, stir for coordination assembly, and after the reaction is completed, filter, wash with water, and dry to obtain.

[0010] Preferably, in step S1, the mass ratio of the amino silane coupling agent to titanium dioxide is 100:3 - 6.

[0011] Preferably, in step S2, the concentration of the cysteine solution is 0.05 to 0.2 mol / L, the molar ratio of cysteine to aminosilane coupling agent is 1.3 to 2:1, and the amidation reaction time is 30 to 60 minutes.

[0012] Preferably, the temperature of the amidation reaction is 140-160°C.

[0013] Preferably, in step S3, the concentration of the cysteine solution is 0.5-1 mol / L, the concentration of the zinc ion solution is 0.1-0.5 mol / L, and the molar ratio of cysteine to zinc ion is 4-5:1.

[0014] Preferably, the zinc ion solution is selected from at least one of aqueous solutions of zinc nitrate, zinc sulfate and zinc acetate.

[0015] Preferably, in step S3, the coordination assembly time is 10 to 60 minutes, more preferably 20 to 30 minutes.

[0016] Preferably, the cysteine solution is an aqueous solution of cysteine.

[0017] Preferably, the aminosilane coupling agent is selected from one or a combination of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane.

[0018] Preferably, the short-chain alcohol is methanol and / or ethanol.

[0019] The modification of the present application is to self-assemble needle-shaped nanocrystals on the surface of titanium dioxide through the coordination effect of antibacterial metal ions and organic ligands. On the one hand, the needle-shaped nanocrystals can destroy the cell membrane of bacteria through physical contact, achieve good bactericidal function, and have excellent durability and long-term effect; on the other hand, they can inhibit the growth of bacteria through the antibacterial effect of metal ions. In the above-mentioned modification process, amino groups are first introduced on the surface of titanium dioxide through the reaction of the hydrolyzate of aminosilane coupling agent with titanium dioxide, and the amino groups are used to undergo amidation reaction with the carboxyl groups in cysteine, so that cysteine is firmly grafted on the surface of titanium dioxide, which is conducive to improving the durability of the antibacterial function of the obtained needle-shaped nanocrystals. Then, the sulfhydryl, amino and carboxyl groups in the cysteine molecule can pre-adsorb metal ions through polarization, providing active sites for the coordination assembly of needle-shaped nanocrystals, so as to induce the growth of MOF crystals on the active sites, thereby forming needle-shaped nanocrystals. The subsequent second soaking in cysteine solution helps to improve the assembly efficiency and the content of MOF crystals, thereby enhancing the antibacterial effect.

[0020] In addition, compared with other antibacterial agents, especially metal ion antibacterial agents, this MOF crystal has higher biosafety performance.

[0021] Preferably, the carrier resin comprises low melt index polypropylene, saturated fatty alcohol and maleic anhydride grafted polypropylene with a mass ratio of 30-50:5-10:5-10, and the melt index of the low melt index polypropylene at 190 °C and 2.16 Kg is 1-10 g / 10 min.

[0022] Preferably, the saturated fatty alcohol has 8-12 carbon atoms.

[0023] Preferably, the saturated fatty alcohol is lauryl alcohol.

[0024] In this application, titanium dioxide mainly serves as a light reflection pigment, and its dosage in the masterbatch raw material is relatively large. With the increase in surface roughness and frictional resistance after modification, the extrusion performance during the melt extrusion process of the masterbatch will be greatly reduced, increasing the residence time and shear stress of the melt in the extruder barrel, resulting in defects such as fisheyes, bubbles, and streaks in the masterbatch, and further appearance defects such as color differences in the processing of bottle caps. To solve this problem, in this application, on the premise of ensuring the compatibility between the carrier resin and the polypropylene base resin, a low melt index polypropylene resin is applied to improve the melt fluidity. In addition, saturated fatty alcohol is added in this application, which plays a significant role in improving the extrusion problem when the melt enters the die head from the barrel, effectively alleviating the above-mentioned color difference problem. In addition, the addition of maleic anhydride polypropylene is used to improve the compatibility and solubility of each component of the masterbatch.

[0025] It should be noted that the reason for using the saturated fatty alcohol with 8-12 carbon atoms is that the specified saturated fatty alcohol can gradually migrate to the surface of the bottle cap after extrusion, playing a certain antistatic role, while the saturated fatty alcohol with more than 12 carbon atoms is usually not easy to migrate. In addition, the above-mentioned preferred lauryl alcohol has relatively good thermal stability.

[0026] Preferably, the dispersant is polyethylene wax.

[0027] Preferably, the titanium dioxide is rutile titanium dioxide.

[0028] Preferably, the D50 particle size of the titanium dioxide is 0.1-10 microns, more preferably 0.1-0.5 microns.

[0029] For the bottle cap and masterbatch raw material of the present disclosure, other processing aids can be added according to the actual processing and use requirements, including but not limited to stabilizers, plasticizers, reinforcing agents, lubricants, flame retardants, antistatic agents, nucleating agents, fillers, pigments, and their dosages are all conventional dosages, or adjusted according to the requirements of the actual situation.

[0030] Second aspect, the present application provides a method for preparing a waterproof and sealed pharmaceutical polypropylene bottle cap, comprising the following steps:

[0031] Prepare raw materials according to the raw material ratio described in any one of the above.

[0032] Mix the masterbatch raw materials, extrude and pelletize to obtain the masterbatch, and set the temperature of the extruder at 180 - 230 °C.

[0033] Melt the high-density ethylene and the masterbatch at 210 - 225 °C and injection mold into the bottle cap to obtain it.

[0034] In summary, the present application has the following beneficial effects:

[0035] By assembling MOF needle-like nanocrystals on the surface of titanium dioxide, the bactericidal effect combining physical and chemical actions can be achieved. In addition, compared with antibacterial agents, etc., this nanocrystal is not easily inactivated and can play a long-term antibacterial role, effectively reducing the probability of the drug and its packaging container being contaminated by environmental microorganisms.

[0036] Furthermore, the present application uses low-melt-index polypropylene, saturated fatty alcohol, and maleic anhydride-grafted polypropylene as the carrier resin of the masterbatch, which can compensate for the loss of melt extrusion performance caused by the superposition of a large amount of titanium dioxide and high frictional resistance, and ensure the appearance quality of the product. Specific embodiments

[0037] Preparation examples

[0038] Preparation example 1, a modified titanium dioxide, the preparation steps are as follows:

[0039] S1. Take 50 g of γ-aminopropyltrimethoxysilane and 1000 g of titanium dioxide (D50 is 0.3 microns), add them to ethanol, mix and stir for 30 min, filter, wash with water, and dry to obtain amino-modified titanium dioxide.

[0040] S2. Add the amino-modified titanium dioxide to 5 L of cysteine aqueous solution (0.1 mol / L), stir and heat to 160 °C, carry out amidation reaction for 30 min, separate the precipitate to obtain amidated titanium dioxide.

[0041] S3. Add the amidated titanium dioxide to 2 L of zinc nitrate aqueous solution (0.3 mol / L), stir and react for 20 min, stir and add it to 4 L of cysteine solution (0.6 mol / L), continue to stir and react after adding, separate the precipitate after 20 min, wash with deionized water until neutral, and dry to constant weight to obtain it.

[0042] Preparation example 2, a modified titanium dioxide, the preparation steps are as follows:

[0043] S1. Take 30 g of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane and 1000 g of titanium dioxide (D50 is 0.3 μm) and add them to ethanol. Mix and stir for 30 minutes. Filter, wash with water, and dry to obtain amino-modified titanium dioxide.

[0044] S2. Add the amino-modified titanium dioxide to 5 L of cysteine aqueous solution (0.1 mol / L), stir and heat to 150° C. to carry out an amidation reaction for 40 min, separate the precipitate, and obtain amidated titanium dioxide.

[0045] S3. Add amidated titanium dioxide to 3 L of zinc nitrate aqueous solution (0.1 mol / L), stir and react for 30 min, then add to 1.8 L of cysteine solution (0.8 mol / L) while stirring. Continue stirring and react after the addition is complete. Separate the precipitate after 20 min, wash with deionized water until neutral, and dry to constant weight.

[0046] Preparation Example 3, a modified titanium dioxide, the preparation steps are as follows:

[0047] S1. Take 60g of γ-aminopropyltrimethoxysilane and 1000g of titanium dioxide (D50 is 0.3 microns) and add them to ethanol. Mix and stir for 30 minutes. Filter, wash with water, and dry to obtain amino-modified titanium dioxide.

[0048] S2. Add the amino-modified titanium dioxide to 3.3 L of cysteine aqueous solution (0.2 mol / L), stir and heat to 140° C. to carry out an amidation reaction for 50 min, separate the precipitate, and obtain amidated titanium dioxide.

[0049] S3. Add amidated titanium dioxide to 2 L of zinc nitrate aqueous solution (0.5 mol / L), stir and react for 10 min, then add to 4 L of cysteine solution (1 mol / L) while stirring. Continue stirring and react after the addition is complete. Separate the precipitate after 30 min, wash with deionized water until neutral, and dry to constant weight.

[0050] Preparation Example 4, a modified titanium dioxide, differs from Preparation Example 1 in that the titanium dioxide is not amino-modified. The specific preparation steps are as follows:

[0051] S1. Take 1000g of titanium dioxide (D50 is 0.3 microns) and add it to 5L of cysteine aqueous solution (0.1mol / L). Stir and heat to 160℃. Stir and react for 30 minutes. Separate the precipitate to obtain intermediate titanium dioxide.

[0052] S23. Add the intermediate titanium dioxide to 2 L of an aqueous zinc nitrate solution (0.3 mol / L), stir and react for 20 min. While stirring, add it to 4 L of a cysteine solution (0.6 mol / L). After adding, continue stirring and reacting. After 20 min, separate the precipitate, wash it with deionized water until neutral, and dry it to constant weight to obtain the product.

[0053] Preparation Example 5. A modified titanium dioxide, which is different from Preparation Example 1 in that step S2 is not carried out. The specific preparation steps are as follows:

[0054] S1. Take 50 g of γ-aminopropyltrimethoxysilane and 1000 g of titanium dioxide (D50 is 0.3 μm), add them to ethanol, mix and stir for 30 min, filter, wash with water, and dry to obtain amino-modified titanium dioxide.

[0055] S2. Add the amino-modified titanium dioxide to 2 L of an aqueous zinc nitrate solution (0.3 mol / L), stir and react for 20 min. While stirring, add it to 4 L of a cysteine solution (0.6 mol / L). After adding, continue stirring and reacting. After 20 min, separate the precipitate, wash it with deionized water until neutral, and dry it to constant weight to obtain the product. Example

[0056] Example 1. A waterproof and antibacterial pharmaceutical polypropylene bottle cap is prepared as follows:

[0057] Preparation of masterbatch: Take 10 kg of raw materials. The raw material ratio is 47.55% of the modified titanium dioxide in Preparation Example 1, 0.53% of an antistatic agent (ethoxylated aliphatic alkylamine), 4.16% of polyethylene wax, 6.95% of lauryl alcohol, 34.73% of low-melting-point polypropylene (Ningbo Formosa Plastics PP1080, melt index is 9 g / 10 min at 190 °C and 2.16 Kg), and 6.08% of maleic anhydride-grafted polypropylene (grafting rate 0.8%). Add the raw materials to a high-speed mixer and mix evenly, then add them to a single-screw extruder for melt extrusion and pelletization. The front section temperature of the extruder is 190 - 195 °C, the rear section temperature is 200 - 215 °C, and the die head temperature is 220 - 230 °C. After underwater pelletization, dehydration, drying, and screening, masterbatch with an average particle size of 2 mm is obtained.

[0058] Injection molding: Melt 95.9 kg of polypropylene (Ningbo Formosa Plastics PP1080, melt index is 9 g / 10 min at 190 °C and 2.16 Kg) and 4.1 kg of the above masterbatch at 210 - 225 °C, and inject the melt into a mold to cool and form. Among them, the front section temperature of the extruder is 222 °C, the middle section temperature is 225 °C, the rear section temperature is 210 °C, and the nozzle temperature is 220 °C.

[0059] Example 2. A waterproof and antibacterial pharmaceutical polypropylene bottle cap is prepared as follows:

[0060] Masterbatch Preparation: 10 kg of raw materials were prepared with the following ratios: 46.27% modified titanium dioxide (prepared in Preparation Example 2), 3.51% polyethylene wax, 5.60% lauryl alcohol, 38.37% low melt index polypropylene (Ningbo Formosa Plastics PP1080, melt index 9 g / 10 min at 190°C and 2.16 kg), and 6.25% maleic anhydride grafted polypropylene (grafting rate 1.0%). The raw materials were mixed thoroughly in a high-speed mixer and then melt-extruded into pellets in a single-screw extruder. The extruder temperature was maintained at 190-195°C, 200-215°C, and 220-230°C. The pellets were then pelletized underwater, dehydrated, dried, and screened to obtain masterbatches with an average particle size of 2 mm.

[0061] Injection Molding: Melt 98.0 kg of polypropylene (Ningbo Formosa Plastics PP1080, melt index 9 g / 10 min at 190°C and 2.16 kg) and 2.0 kg of the aforementioned masterbatch at 210-225°C. The melt is injected into a mold and cooled to form the product. The extruder temperature is set at 222°C for the front section, 225°C for the middle section, 210°C for the back section, and 220°C for the nozzle.

[0062] Example 3, a waterproof and antibacterial medicinal polypropylene bottle cap, the preparation method is as follows:

[0063] Masterbatch Preparation: 10 kg of raw materials were prepared using the following ratios: 47.55% modified titanium dioxide (prepared in Preparation Example 3), 4.16% polyethylene wax, 6.95% decanol, 34.73% low melt index polypropylene (Yanshan Petrochemical K8003, melt index 2 g / 10 min at 190°C and 2.16 kg), and 6.08% maleic anhydride grafted polypropylene (grafting rate 0.8%). The raw materials were mixed thoroughly in a high-speed mixer and then melt-extruded and pelletized in a single-screw extruder at a front-end temperature of 180-190°C, a rear-end temperature of 195-205°C, and a die head temperature of 210-225°C. The mixture was pelletized underwater, dehydrated, dried, and screened to obtain a masterbatch with an average particle size of 2 mm.

[0064] Injection molding: 95.3 kg of polypropylene (Yanshan Petrochemical K8003, melt index 2 g / 10 min at 190°C and 2.16 kg) and 4.7 kg of the aforementioned masterbatch were melted at 210-220°C. The melt was injected into a mold and cooled to form the product. The extruder temperature was set at 215°C for the front section, 220°C for the middle section, 210°C for the back section, and 220°C for the nozzle.

[0065] Example 4, a waterproof and antibacterial medicinal polypropylene bottle cap, differs from Example 1 in that lauryl alcohol is replaced by an equal amount of low melt index polypropylene (Ningbo Formosa Plastics PP1080, melt index of 9 g / 10 min at 190°C and 2.16 kg).

[0066] Example 5, a waterproof and antibacterial medicinal polypropylene bottle cap, differs from Example 1 in that the maleic anhydride grafted polypropylene is replaced by an equal amount of low melt index polypropylene (Ningbo Formosa Plastics PP1080, melt index of 9 g / 10 min at 190°C and 2.16 kg).

[0067] Example 6, a waterproof and antibacterial medicinal polypropylene bottle cap, which differs from Example 1 in that an equal amount of polypropylene (Formosa Plastics PP5250T, melt index of 22 g / 10 min at 190°C and 2.16 kg) is used to replace the low melt index polypropylene (Ningbo Formosa Plastics PP1080, melt index of 9 g / 10 min at 190°C and 2.16 kg). Comparative Example

[0068] Comparative Example 1, a waterproof and antibacterial medicinal polypropylene bottle cap, differs from Example 1 in that the modified titanium dioxide of Preparation Example 1 is replaced by an equal amount of modified titanium dioxide of Preparation Example 4.

[0069] Comparative Example 2, a waterproof and antibacterial medicinal polypropylene bottle cap, differs from Example 1 in that the modified titanium dioxide of Preparation Example 1 is replaced by an equal amount of the modified titanium dioxide of Preparation Example 5.

[0070] Comparative Example 3, a waterproof and antibacterial medicinal polypropylene bottle cap, differs from Example 1 in that unmodified titanium dioxide (D50 is 0.3 μm) is used instead of the modified titanium dioxide in Preparation Example 1.

[0071] Comparative Example 4, a waterproof and antibacterial medicinal polypropylene bottle cap, differs from Comparative Example 3 in that the pigment ratio of the masterbatch is 45.55% titanium dioxide, 0.53% antistatic agent (ethoxylated fatty alkylamine), 2% zinc ion antibacterial agent, 4.16% polyethylene wax, 6.95% lauryl alcohol, 34.73% low melt index polypropylene (Ningbo Formosa Plastics PP1080, melt index of 9 g / 10 min at 190°C and 2.16 kg), and 6.08% maleic anhydride grafted polypropylene (grafting rate 0.8%).

[0072] The following experiments illustrate the beneficial effects of this application:

[0073] Test 1: Antibacterial performance test of polypropylene bottle caps

[0074] (1)Refer to the film - sticking method in the light industry standard QB / T 2591 - 2003 "Antibacterial Plastics - Test Methods for Antibacterial Properties and Antibacterial Effects", and investigate the antibacterial rate of the samples for 24 hours. The test bacteria used are Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC 25922). Cut the bottom flat part (the smooth outer surface is the test surface) of the injection - molded polypropylene bottle caps in the above - mentioned examples and comparative examples into specimens (with a diameter of 40 mm), and prepare 5 specimens for each group. The determination of the total number of colonies refers to the counting method in GB / T 4789.2 - 2003. The calculation formula for the antibacterial rate is as follows:

[0075] R (%)=(B - C) / B×100%

[0076] Where:

[0077] R - antibacterial rate, %;

[0078] B - average number of recovered bacteria in the blank control sample, cfu / sheet;

[0079] C - average number of recovered bacteria in the antibacterial plastic sample, cfu / sheet.

[0080] (2)Long - term antibacterial performance test

[0081] Prepare specimens according to the requirements in (1), add them to 500 mL of sterilized saline, after sterilization at 120 °C, add 10 mL of a bacterial solution with a concentration of 5×10 5 cfu / mL (the bacterial strain is Escherichia coli), and then detect the antibacterial rate of the specimens again after placing them at 30 °C for 100 days.

[0082] Test 2: Color difference test of the bottle cap

[0083] Randomly select 10 bottle caps prepared in the examples and comparative examples, visually detect whether there is an obvious difference in color from the standard bottle cap. If there is no obvious difference in color between all bottle cap specimens and the standard bottle cap, it is considered qualified.

[0084] Table 1. Performance test results

[0085]

[0086] Combined with Examples 1 - 6 and Comparative Examples 3 - 4 and Table 1, it can be seen that through the solution of this application, the modification of titanium dioxide in this application can significantly improve the long - term antibacterial performance of polypropylene bottle caps. Further, from Comparative Examples 1 - 2, it can be known that the amino modification and the pre - reaction step of cysteine and amino groups play a key role in improving the long - term antibacterial performance of the bottle cap. The reason may be that the pre - bonding of cysteine helps to induce the growth of subsequent MOF crystals at specific positions and directions, resulting in needle - shaped nanocrystals with physical bactericidal effects.

[0087] Combining Examples 1-3 with Examples 4-6 and Table 1, it can be seen that the specific selection of the carrier resin can effectively improve the color uniformity of the bottle caps and reduce color differences from standard bottle caps. This may be because the specifically selected carrier resin can alleviate the negative impact of high-friction titanium dioxide content on melt flow, reduce quality defects in the masterbatch, and thus ensure the appearance quality of the bottle caps.

[0088] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A waterproof and antibacterial pharmaceutical polypropylene bottle cap, characterized in that, The raw material of the bottle cap contains 1.5 - 4.7 wt% of masterbatch, and the balance is polypropylene; the raw materials of the masterbatch include 45 - 50 wt% of modified titanium dioxide, 3 - 5 wt% of dispersant, and the balance is carrier resin; the carrier resin includes low melt index polypropylene, saturated fatty alcohol with 8 - 12 carbon atoms, and maleic anhydride grafted polypropylene with a mass ratio of 30 - 50:5 - 10:5 - 10, and the melt index of the low melt index polypropylene at 190 °C and 2.16 Kg is 1 - 10 g / 10 min; The preparation method of the modified titanium dioxide is as follows: S1. Mix and stir an amino silane coupling agent and titanium dioxide in a short-chain alcohol to obtain amino-modified titanium dioxide; S2. Add the amino-modified titanium dioxide into a cysteine solution for amidation reaction to obtain amidated titanium dioxide; S3. Add the amidated titanium dioxide into a zinc ion solution, stir evenly, then add a cysteine solution, stir for coordination assembly, and after the reaction is completed, filter, wash with water, and dry to obtain.

2. The bottle cap according to claim 1, characterized in that, In step S1, the mass ratio of the amino silane coupling agent to titanium dioxide is 100:3 - 6.

3. The bottle cap according to claim 1, characterized in that, In step S2, the concentration of the cysteine solution is 0.05 - 0.2 mol / L, the molar ratio of the used cysteine to the amino silane coupling agent is 1.3 - 2:1, and the amidation reaction time is 30 - 60 minutes.

4. The bottle cap according to claim 1, characterized in that, In step S3, the concentration of the cysteine solution is 0.5 - 1 mol / L, the concentration of the zinc ion solution is 0.1 - 0.5 mol / L, and the molar ratio of the cysteine to the zinc ion is 4 - 5:

1.

5. The bottle cap according to claim 1, characterized in that, The amino silane coupling agent is selected from one or a combination of several of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane.

6. The bottle cap according to claim 1, characterized in that, The saturated fatty alcohol is lauryl alcohol.

7. The bottle cap according to claim 1, characterized in that, The dispersant is calcium stearate and zinc stearate with a mass ratio of 1 - 2:1 - 2.

8. A preparation method of a waterproof and antibacterial medicinal polypropylene bottle cap, characterized in that, It includes: Prepare raw materials according to the raw material ratio of the bottle cap as described in any one of claims 1 - 7; Mix the masterbatch raw materials, extrude and pelletize to obtain masterbatch, and the temperature of the extruder is set at 180 - 230 °C; Melt high-density ethylene and masterbatch at 210 - 225 °C and injection mold into a bottle cap to obtain.

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