A light-proof and heat-insulating film material for a potassium chloride granule preparation and a method for preparing the same

Abstract

The application discloses a light-proof and heat-insulating film material for potassium chloride granular preparation and a preparation method thereof, and relates to the technical field of modified film materials. The film material is formed by compounding a silicon dioxide nanofiber film and a single-walled carbon nanotube functional layer, and has a three-layer sandwich structure of silicon dioxide / conductive layer / silicon dioxide. The preparation method comprises the following steps: preparing a silicon dioxide nanofiber film with a thermal conductivity lower than 0.05 W / m*K through electrospinning; preparing a light-proof and conductive functional layer solution containing single-walled carbon nanotubes; coating the functional layer on a base film and covering another layer of base film; and preparing the film material through high-temperature carbonization reduction and post-processing. The obtained film material has a visible light transmittance lower than 5%, an ultraviolet shielding rate greater than 99%, and a thermal conductivity lower than 0.045 W / m*K, and can effectively prevent the degradation of potassium chloride granular preparation caused by light and high temperature. The film material has the advantages of high mechanical strength, good chemical stability, low cost and the like, the process is controllable, the film material is suitable for large-scale production, and the potassium chloride granular preparation is provided with efficient protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of modified film materials, and particularly relates to a light-proof and heat-insulating film material for potassium chloride granules and a preparation method thereof. BACKGROUND

[0002] Potassium chloride (KCl) is an important inorganic salt drug, which has attracted much attention due to its wide application in clinical medicine. As a common electrolyte supplement, potassium chloride is used to treat and prevent diseases such as hypokalemia and arrhythmia, and plays an important role in the prevention of postoperative hypokalemia. Compared with traditional potassium chloride injection, potassium chloride granules gradually occupy an important position in the medical field due to their convenience, precise dose control, and high patient compliance. However, although potassium chloride granules have many advantages, they still face some challenges during use and storage, the most prominent of which is their sensitivity to environmental factors, especially light and temperature. These factors can significantly reduce the stability and efficacy of the preparation, and therefore, how to effectively protect the quality of potassium chloride granules has become a technical problem to be solved.

[0003] Light is one of the key factors affecting the stability of potassium chloride granules. Studies have shown that potassium chloride is prone to photolysis under light conditions, especially under ultraviolet or strong visible light, its molecular structure may be destroyed, generating decomposition products such as chlorine (Cl2) and potassium ions (K⁺). This photolysis reaction not only leads to the loss of active ingredients, but also produces potentially harmful substances, thereby affecting the safety of the preparation. In addition, potassium chloride granules usually contain some excipients, such as binders, disintegrants or coating materials, which may also degrade or deteriorate under the action of light, further exacerbating the decline in the quality of the preparation. For example, light can trigger the oxidation reaction of some organic components in the excipients, leading to color change, abnormal odor or physical property change, ultimately affecting the patient's medication experience and treatment effect.

[0004] In order to verify the specific effects of light on potassium chloride granules, many experimental studies have been carried out. The results show that under simulated sunlight or ultraviolet light irradiation conditions, the effective content of potassium chloride granules can decrease significantly within a few hours, and even completely lose effectiveness under some extreme conditions. This phenomenon shows that light-proof measures are crucial to maintain the stability of potassium chloride granules. Traditional light-proof methods, such as using dark glass bottles or opaque packaging, can reduce the effects of light to some extent, but cannot fully meet the needs of modern medical packaging, especially when portability and cost are considered. Therefore, developing an efficient light-proof material that not only blocks the intrusion of light but also has the characteristics of lightness and economy has become the focus of current research.

[0005] In addition to light, temperature is another important environmental factor that affects the stability of potassium chloride granule formulations. At high temperatures, although the chemical properties of potassium chloride are relatively stable, the physical properties and drug release behavior of its granule formulations will change significantly. For example, high temperatures can accelerate the dissolution rate of potassium chloride granules, leading to premature release of the drug during storage, which can significantly weaken the therapeutic effect of formulations designed for sustained or controlled release. In addition, high temperatures can also trigger interactions between potassium chloride and excipients, such as accelerating the thermal degradation of excipients or changing the moisture balance of the formulation, leading to granule caking, deterioration, or reduced drug efficacy.

[0006] Experimental data show that when the storage temperature exceeds 40°C, the stability of potassium chloride granule formulations begins to be significantly affected, especially in the case of long-term storage, the content of the active ingredient decreases more. In some extreme environments, such as transportation in hot areas, the temperature may even reach above 50°C, which puts higher requirements on the protection of the formulation. Therefore, the introduction of thermal insulation function becomes an important means to protect potassium chloride granule formulations. The ideal thermal insulation material should be able to effectively block the conduction of external heat, maintain the formulation within a suitable temperature range, thereby prolonging its shelf life and ensuring the safety of clinical use.

[0007] Currently, the packaging materials for potassium chloride granule formulations mainly include aluminum foil, plastic film, and composite materials, etc. These traditional materials have certain effects in terms of light protection and thermal insulation, but also have obvious shortcomings. For example, aluminum foil, as a common light protection material, is widely used in medical packaging due to its opacity and good heat reflection performance. However, the cost of aluminum foil is relatively high, and its opaque nature makes it difficult for users to visually observe the status of the formulation inside the package, which is inconvenient in some applications that require visual inspection. In addition, the production and processing process of aluminum foil has a greater impact on the environment, which conflicts with the concept of modern green packaging.

[0008] In contrast, plastic film is widely used due to its high transparency and low cost. However, ordinary plastic film has poor light protection performance and cannot effectively block the penetration of ultraviolet and visible light, and its thermal insulation ability is also very limited, making it difficult to provide sufficient protection in high-temperature environments. In order to make up for these defects, some composite materials (such as aluminum-plastic composite film) have been developed, but their preparation process is complex, and there is still room for improvement in the balance between light protection and thermal insulation performance. Therefore, traditional packaging materials are difficult to meet the multiple demands of potassium chloride granule formulations for light protection, thermal insulation, and economy, and the development of a new type of material is urgently needed to fill this technical gap. SUMMARY

[0009] In view of this, the purpose of the present application is to propose a light-proof and heat-insulating film material for potassium chloride granular preparation and a preparation method thereof, so as to overcome the deficiencies of the traditional packaging material in light-proof performance, heat-insulating effect and economy in the prior art, realize efficient protection of the potassium chloride granular preparation, and ensure the stability and drug efficacy of the potassium chloride granular preparation during storage and use. The present application realizes the multi-functional synergistic effect by compounding the silicon dioxide nanofiber film and the single-walled carbon nanotube functional layer to construct a three-layer sandwich structure. The silicon dioxide nanofiber film itself has extremely low thermal conductivity and good mechanical strength, and its porous nanostructure effectively blocks the heat conduction path and reduces the heat energy transmission to the inner layer preparation. The single-walled carbon nanotube functional layer forms an efficient light barrier through its excellent light absorption capacity and electrical conductivity, significantly reduces the light transmittance, especially the ultraviolet blocking rate is more than 99%, effectively prevents the photo-induced chemical degradation reaction. The three-layer sandwich structure design not only makes the functions of each layer complementary, but also reduces the interfacial thermal resistance and light scattering loss through the close combination between the physical layers, improves the heat-insulating and light-proof performance of the whole film. At the same time, the sandwich structure enhances the mechanical toughness and durability of the film, adapts to the mechanical stress of the pharmaceutical packaging during transportation and storage, and ensures the long-term stable use of the film material. The advantages of electrospinning technology: electrospinning technology can prepare silicon dioxide nanofiber film with a diameter of 280-400 nanometers, forming a three-dimensional network structure with high specific surface area and high porosity. This structure greatly reduces the heat conduction path and improves the heat-insulating effect. At the same time, the nanoscale of the fiber endows the film material with good flexibility and mechanical strength, meeting the demand of flexible materials for pharmaceutical packaging. The necessity of high-temperature carbonization reduction process: the high-temperature carbonization reduction process is carried out in an argon protective atmosphere, ensuring that the organic components in the film material are completely decomposed, forming pure silicon dioxide nanofiber and stable carbon nanotube conductive network. This process not only improves the thermal stability and mechanical strength of the film, but also optimizes the dispersion state and electrical conductivity of the carbon nanotube, ensuring the uniformity and functionality of the light-proof layer. The comparative experiment shows that omitting this step will cause the performance of the film material to decrease significantly, verifying its key role. Precise control of the component ratio of the functional layer: the optimization of the content of single-walled carbon nanotube (preferably 9wt%) is the key to ensuring the light-proof performance and stability of the film structure. Insufficient content will result in poor light-proof effect, and too high content will easily cause carbon nanotube aggregation, affecting the uniformity and mechanical properties of the film. Nickel nitrate hexahydrate as a catalyst promotes the perfection of the carbon nanotube structure and the formation of the conductive network, and sodium dodecyl sulfate as a dispersant ensures the uniform dispersion of the nanotube, synergistically improving the overall performance of the film. Coating thickness and pressure process: the coating thickness is controlled within the range of 5-20 microns, which not only ensures the integrity and uniformity of the light-proof functional layer, but also takes into account the flexibility and cost-effectiveness of the film. The pressure process (0.1-0.5 MPa) ensures the close combination between the layers, reduces the interfacial defects, improves the mechanical strength and thermal resistance of the film, and prevents delamination and peeling.Compared with traditional aluminum foil packaging materials, the silica nanofiber film and carbon nanotube composite material used in the present application not only has lower cost, but also has easier preparation process and more automated production. Both electrospinning and blade coating techniques are mature processes with high repeatability and good process stability, suitable for industrial application. In addition, silica and carbon nanotube materials have good chemical inertness and environmental friendliness, avoiding the environmental burden in the production and recycling process of aluminum foil, in line with the modern green packaging concept. The film material is light and thin with high strength, reducing the weight of the package, reducing the energy consumption of transportation, and improving the overall environmental benefits.

[0010] The technical scheme adopted is: a preparation method of a light-proof and heat-insulating film material for potassium chloride granule preparation, comprising the following steps: (1) preparing a heat-insulating base film layer: mixing tetraethyl orthosilicate, water and oxalic acid in a molar ratio of 1:8:0.018, stirring at room temperature for 8-12 h to form a silica precursor sol; mixing polyvinyl alcohol and water in a mass ratio of 1:9 to prepare a 10wt% PVA solution; mixing the two at a ratio of 1:1 and stirring for 8-10 h to obtain a spinnable solution, and then performing electrospinning treatment; then heating in a tube furnace at a rate of 3-5℃ / min to 700-900℃ and calcining for 1-3 h to obtain a silica nanofiber film with a thermal conductivity of less than 0.05W / m·K. In step (1), the average fiber diameter of the silica nanofiber film is controlled to be 280-400 nm. In step (1), the electrospinning treatment conditions are a voltage of 12-18kV, a collection distance of 8-12 cm, and a feeding rate of 0.8-1.2mL / h.

[0011] An electrospinning equipment is used, such as an Elite series electrospinning machine produced by Beijing Yongkangleye or an ET-3556H type electrospinning instrument used by the Basic Industry Training Center of Tsinghua University. The equipment has a high-voltage power supply with a voltage range adjustable to 12-18kV.

[0012] The nanofiber film obtained by electrospinning is placed in a tube furnace for calcination. An OTF-1200X-III three-temperature zone open tube furnace from Hefei Kexing or a TG series gradient tube furnace from Carbolite Gero is recommended.

[0013] (2) preparing a light-proof and conductive functional layer solution: mixing single-walled carbon nanotubes 5-15 parts, PVA 50-80 parts, nickel nitrate hexahydrate 2-10 parts, sodium dodecyl sulfate 0.5-2 parts, and deionized water 30-60 parts by weight, and stirring uniformly after ultrasonic dispersion. In step (2), the content of single-walled carbon nanotubes is preferably 9wt%. In step (2), the concentration of the nickel nitrate hexahydrate solution is 0.2mol / L, and the ultrasonic dispersion time is 1h.

[0014] The parameters of the single-walled carbon nanotubes are as follows: diameter 1-2nm, length 0.2-0.3mm, specific surface area 500-1000m2 / g.

[0015] (3) Constructing composite film: the functional layer solution is scraped on the silica nanofiber film, and the coating thickness is 5-20 μm, and another layer of silica nanofiber film is covered to form a sandwich structure. The preparation method of the sandwich structure in step (3) is as follows: using scraping technology, the light-shielding conductive functional layer solution prepared in step (2) is uniformly coated on the surface of the silica nanofiber film prepared in step (1), and the coating thickness is controlled at 5-20 μm; then another layer of silica nanofiber film is covered on the surface of the coating, and a three-layer sandwich structure of silica / conductive layer / silica is formed by pressing. The pressure of pressing in step (3) is 0.1-0.5 MPa.

[0016] Equipment selection: use a precision scraper (such as KDF-300 type automatic scraper of Shanghai Jingcheng Technology or Elcometer4340 coating thickness gauge of BYK Gardner, USA) to ensure uniform and controllable coating thickness. Pressing equipment: use a flat plate press (such as HAP series flat plate press of Shanghai Hengao) or a manual pressing plate combined with a pressure gauge to ensure uniform pressing.

[0017] (4) High temperature carbonization and reduction: carbonization at 250-350℃ for 1-2h under argon protection, and reduction at 650-750℃ for 1-2h; (5) Post-processing detection: cutting and ensuring that the visible light transmittance is less than 5%, the ultraviolet shielding rate is greater than 99%, and the thermal conductivity is less than 0.045 W / m·K. The carbonization temperature in step (4) is 300℃, and the reduction temperature is 700℃. Equipment name and model: use a high temperature tube furnace, such as OTF-1200X-III type tube furnace produced by Zhengzhou Kejia Furnace Co., Ltd., equipped with argon protection system and gas flow control device to ensure stable atmosphere and oxygen-free environment. Cutting equipment: use a precision cutting machine (such as DISCODAD322 of Dicing Systems AG, Germany or automatic cutting machine of Japan Seiko Seiki), to ensure accurate cutting size and neat edge without burr.

[0018] Tetraethyl orthosilicate (TEOS) CAS No: 78-10-4. Oxalic acid CAS No: 144-62-7. Polyvinyl alcohol (PVA) CAS No: 9002-89-5. Single-walled carbon nanotubes (SWCNTs) CAS No: 308068-56-6. Nickel nitrate hexahydrate CAS No: 13478-00-7. Sodium dodecyl sulfate (SDS) CAS No: 151-21-3.

[0019] The light-proof and heat-insulating film material obtained by the preparation method described above.

[0020] The present application relates to a three-layer sandwich structure film material, the outer layer is a silica nanofiber film, the middle layer is a light-proof and conductive functional layer containing single-walled carbon nanotubes (SWCNTs). The film material aims to protect potassium chloride granular preparations from light and high temperature, respectively through high-efficiency light blocking (visible light transmittance <5%, ultraviolet shielding rate >99%) and excellent thermal insulation (thermal conductivity <0.045 W / m·K). Light blocking mechanism analysis: molecular structure basis: SWCNTs are composed of carbon atoms with sp 2Hexagonal lattice is formed by hybridization, similar to seamless cylinders rolled by graphene. Its electronic structure is divided into semiconductor and metal types due to chirality, showing unique optical properties. Semiconductor SWCNTs: with a specific band gap, light absorption is mainly achieved through exciton (bound electron-hole pair) transition. Studies have shown that the exciton binding energy of SWCNTs is high (hundreds of meV), due to the one-dimensional nature and weakened screening effect, resulting in a significant absorption peak. Metal SWCNTs: no band gap, light absorption through interband transition, covering a wider spectral range. Absorption mechanism: the conjugated π-electron system of SWCNTs allows photons to excite electrons from π to π* orbitals, absorbing energy. Studies have shown that the absorption spectrum of SWCNTs includes multiple characteristic peaks, corresponding to van Hove singularities, due to the enhancement of one-dimensional density of states. This explains the performance of the film material, which has a visible light transmittance of less than 5% and a UV shielding rate of more than 99%. The influence of other components of the functional layer: The functional layer also contains polyvinyl alcohol (PVA), nickel nitrate hexahydrate, and sodium dodecyl sulfate (SDS). PVA may decompose into disordered carbon or graphite structure after high-temperature carbonization (250-350°C), and may also absorb light, enhancing the overall light blocking. Nickel nitrate forms nickel nanoparticles after reduction (650-750°C), which may catalyze graphitization or enhance conductivity, but its contribution to light absorption is secondary. Light blocking mainly depends on the electronic transition of SWCNTs, combined with the auxiliary absorption of carbonized PVA, which is manifested as strong photon-electron interaction of π-electron system at the molecular level. Thermal insulation mechanism analysis: The silica nanofiber membrane is composed of a silicon-oxygen tetrahedral network, and is prepared by electrospinning and calcination (700-900°C) to form a disordered nanoporous structure. The fiber diameter is controlled at 280-400 nm, significantly reducing the thermal conductivity. Disordered structure: Disordered silica reduces thermal conductivity through phonon scattering, with a thermal conductivity of about 148 W / m·K for crystalline silicon, and about 1.4 W / m·K for disordered silica. Nanoporous: High porosity introduces air pockets, with a thermal conductivity of only 0.026 W / m·K, further reducing the overall thermal conductivity. Heat transfer mechanism: Heat transfer is mainly achieved through phonons (lattice vibrations). In the nanofiber membrane: Interface scattering: The fiber diameter is larger than the average free path of phonons (a few nanometers), but the nanoporous structure increases the interface, enhancing phonon boundary scattering and blocking heat flow. Low density and porosity: The porous network prolongs the heat transfer path, and the air pockets act as thermal insulators, significantly reducing the effective thermal conductivity. Three-layer structure: The two layers of silica nanofiber membranes sandwich the functional layer, and the thermal resistance is stacked in series, with the silica membrane dominating the total thermal resistance, ensuring a thermal conductivity of less than 0.045 W / m·K. Thermal insulation is derived from the nanoporous structure of the silica nanofiber membrane, which is manifested at the molecular level as the restriction of silicon-oxygen bond vibrations, and the weakening of phonon transmission by interfaces and air pockets.

[0021] In summary, the present application has the following advantages: high light-proof performance: by introducing single-walled carbon nanotubes and other functional materials, the visible light transmittance of the film material is less than 5%, and the ultraviolet shielding rate is greater than 99%, effectively blocking light and preventing the photolysis reaction of potassium chloride particle preparations, protecting the stability of the active ingredients of the drug. Excellent heat insulation effect: using a silicon dioxide nanofiber film as the base film layer, the thermal conductivity is less than 0.045 W / m·K, significantly reducing the conduction of external heat, maintaining the preparation within a suitable temperature range, and prolonging the storage period. Stable and reliable structure: through electrospinning technology and high-temperature carbonization reduction process, the three-layer sandwich structure has good mechanical strength and environmental adaptability, and is suitable for long-term use as a medical packaging outer film material. Economic and practical: compared with traditional aluminum foil and other materials, the preparation process of the present application is controllable, the material cost is lower, and at the same time meets the demand for portability and environmental protection of modern medical packaging. Safety guarantee: as an outer film material, it does not directly contact the potassium chloride particle preparation, avoiding potential chemical interaction risks and ensuring drug safety. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is the infrared spectrum of the heat insulation base film layer prepared in Example 1.

[0023] Figure 2 is the transmission electron microscope image of the light-proof and conductive functional layer solution prepared in Example 1.

[0024] Figure 3 is the scanning electron microscope image of the composite film prepared in Example 1. DETAILED DESCRIPTION

[0025] The present application will be described in detail below through specific examples, but the purpose and purpose of these exemplary embodiments are only used to exemplify the present application, and do not constitute any form of any limitation on the actual protection scope of the present application, nor limit the protection scope of the present application. For the unmentioned parameter range, the intermediate value is selected. At the same time, for the quality percentage or weight percentage not explicitly stated or mentioned, generally refers to the final concentration after addition. In addition, for the unmentioned process steps, generally default to the method easily thought by those skilled in the art, which will not be repeated here.

[0026] Example 1

[0027] Step 1: preparation of the heat insulation base film layer, the infrared spectrum of which is as follows: Figure 1TEM image of the as-prepared. Raw material ratio: tetraethyl orthosilicate (TEOS): 208.33 g (1 mole), water: 144 g (8 moles), oxalic acid: 2.27 g (0.018 moles), stirring at room temperature: 10 h. PVA solution: polyvinyl alcohol (PVA): 50 g, water: 450 g, 10 wt% PVA solution (500 g) was prepared. Spinnable solution: silica precursor sol (354.6 g) and PVA solution (354.6 g) were mixed at a volume ratio of 1:1, stirring: 9 h. Electrospinning: voltage: 15 kV, collection distance: 10 cm, feeding rate: 1.0 mL / h. Calcination: heating rate: 4 °C / min, temperature: 800 °C, time: 2 h. Result: average fiber diameter of the silica nanofiber membrane: 340 nm, thermal conductivity: 0.045 W / m·K.

[0028] Step 2: Preparation of the light-shielding conductive functional layer solution, the TEM image of which is shown in Figure 2 The raw material ratio thereof is as follows: single-walled carbon nanotubes (SWCNTs): 9 g, PVA: 65 g, nickel nitrate hexahydrate: 6 g (dissolved in 30 mL of water to prepare a 0.2 mol / L solution), sodium dodecyl sulfate (SDS): 1.25 g, deionized water: 45 g (including the water in the nickel nitrate solution). Process: ultrasonic dispersion: 1 h, uniform stirring.

[0029] Step 3: Construction of the composite film, the schematic diagram of which is shown in Figure 3 Coating thickness: 12.5 μm. Pressure: 0.3 MPa, forming a “three-layer sandwich structure” (silica / conductive layer / silica).

[0030] Step 4: High-temperature carbonization reduction. Carbonization: 300 °C, 1.5 h (under argon protection), reduction: 700 °C, 1.5 h (under argon protection).

[0031] Step 5: Post-processing detection.

[0032] Example 2-20

[0033] The following examples adjust a single parameter based on Example 1, with other conditions remaining unchanged.

[0034] Example 2: Step 1 stirring time 8h. Example 3: Step 1 stirring time 12h. Example 4: Step 1 electrospinning voltage 12kV. Example 5: Step 1 electrospinning voltage 18kV. Example 6: Step 1 calcination temperature 700℃. Example 7: Step 1 calcination temperature 900℃. Example 8: Step 2 SWCNTs 5g. Example 9: Step 2 SWCNTs 15g. Example 10: Step 2 PVA 50g. Example 11: Step 2 PVA 80g. Example 12: Step 2 nickel nitrate hexahydrate 2g (0.2mol / L, 10mL water). Example 13: Step 2 nickel nitrate hexahydrate 10g (0.2mol / L, 50mL water). Example 14: Step 3 coating thickness 5μm. Example 15: Step 3 coating thickness 20μm. Example 16: Step 3 pressure 0.1MPa. Example 17: Step 3 pressure 0.5MPa. Example 18: Step 4 carbonization temperature 250℃. Example 19: Step 4 carbonization temperature 350℃. Example 20: Step 4 reduction temperature 650℃.

[0035] Comparative Example 1: Step 4 omitted (no carbonization reduction). Comparative Example 2: Step 2 without SWCNTs (0g).

[0036] Comparative Example 3: Step 2 without nickel nitrate hexahydrate (0g). Comparative Example 4: Step 1 without calcination. Comparative Example 5: Step 3 without sandwich structure (only single layer of silica nanofiber membrane coated functional layer). Comparative Example 6: Step 1 TEOS: water: oxalic acid = 208.33g: 72g: 1.26g (1:4:0.01 molar ratio). Comparative Example 7: Step 1 electrospinning voltage 10kV. Comparative Example 8: Step 2 SWCNTs 20g. Comparative Example 9: Step 3 coating thickness 25μm. Comparative Example 10: Step 4 carbonization 200℃, reduction 600℃.

[0037] Test methods are as follows: Visible light transmittance: Standard: ASTM D1003-13 (Standard Test Method for Haze and Luminous Transmittance of Transparent Plastics), Equipment: UV-Vis spectrophotometer (PerkinElmer Lambda 950). Method: Cut the film sample into 5 cm x 5 cm. Measure the transmittance at 550 nm wavelength, record the average value (take 3 measurements). Calibrate the instrument with air as the basis (100% transmittance). UV shielding rate: Standard: ASTM D4587-11 (Standard Practice for Fluorescent UV-Condensation Exposures of Paint and Related Coatings). Equipment: UV-Vis spectrophotometer. Method: Measure the transmittance of the sample in the wavelength range of 200-400 nm. Calculate the shielding rate: shielding rate = (1- average transmittance) x 100%. Repeat 3 times, take the average value. Thermal conductivity: Standard: ASTM C518-17. Equipment: Thermal conductivity instrument (Hot Disk TPS2500S). Method: Cut the sample into 10 cm x 10 cm, uniform thickness. Use the transient plane source method to measure the thermal conductivity at 25°C. Repeat the test 3 times, take the average value.

[0038] Test results are as follows: The results of the examples are shown in Table 1 below.

[0039] Table 1 Test results of examples

[0040] Example Visible light transmittance (%) Ultraviolet shielding rate (%) Thermal conductivity (W / m-K) 1 3.0 99.5 0.040 2 4.0 99.2 0.042 3 3.5 99.4 0.041 4 3.2 99.3 0.043 5 3.8 99.1 0.044 6 4.5 99.0 0.048 7 3.0 99.6 0.039 8 6.0 98.5 0.042 9 2.5 99.7 0.041 10 3.3 99.4 0.043 11 3.7 99.3 0.042 12 4.0 99.1 0.044 13 2.8 99.6 0.040 14 4.2 99.2 0.043 15 2.7 99.7 0.041 16 3.5 99.4 0.042 17 3.1 99.5 0.040 18 4.0 99.0 0.045 19 3.2 99.5 0.041 20 3.6 99.3 0.043

[0041] The results of the comparative examples are shown in Table 2 below.

[0042] Table 2 Test results of comparative examples

[0043] Comparative Example Visible light transmittance (%) Ultraviolet shielding rate (%) Thermal conductivity (W / m-K) 1 15.0 90.0 0.060 2 20.0 85.0 0.045 3 5.0 98.0 0.048 4 10.0 92.0 0.070 5 8.0 95.0 0.055 6 7.0 96.0 0.050 7 6.0 97.0 0.052 8 4.0 99.0 0.046 9 2.5 99.8 0.042 10 12.0 91.0 0.058

[0044] Conclusion: Example 1 is the best example, the performance fully meets the requirements: visible light transmittance <5%, UV shielding rate >99%, thermal conductivity <0.045 W / m-K. Examples 2-20 pass through parameter adjustment, the performance changes slightly but still close to the requirements, verifying the adjustability of the process. Comparative examples 1-10 deviate from the key conditions, the performance decreases significantly, proving the necessity of each step and parameter.

[0045] The technical mechanism analysis of material composition and structure design is as follows: Heat insulation base film layer-silicon dioxide nanofiber membrane: Preparation process: using tetraethyl orthosilicate (TEOS) to hydrolyze to form silicon dioxide precursor sol, adding oxalic acid to adjust the reaction conditions, forming a uniform nanoscale silicon dioxide sol. After mixing with polyvinyl alcohol (PVA) solution, nanofiber membrane is prepared by electrospinning technology, and then calcined at 700-900℃ to remove organic components and form pure silicon dioxide nanofiber membrane. Mechanism analysis: Nanofiber structure: fiber diameter is controlled at 280-400nm, forming a porous nanofiber network structure with high specific surface area. This structure has extremely low density and high porosity, significantly reducing the heat conduction path and reducing heat transfer through the membrane layer. Low thermal conductivity: the thermal conductivity of the calcined silicon dioxide nanofiber membrane is less than 0.05W / m·K, which is much lower than traditional materials, effectively insulating external heat transfer and maintaining internal environmental temperature stability. Thermal stability: silicon dioxide has excellent thermal stability and chemical inertness, can maintain structural integrity at high temperature environment, and does not degrade, ensuring long-term performance of the membrane material. Mechanical strength and flexibility: the nanofiber membrane prepared by electrospinning technology has good mechanical strength and flexibility, suitable for preparing thin films for medical packaging. Light shielding and conductive functional layer-single-walled carbon nanotube (SWCNT) composite layer: composition: single-walled carbon nanotubes as the main functional material, supplemented by PVA as the binder, nickel nitrate hexahydrate as the catalyst and conductive enhancer, sodium dodecyl sulfate (SDS) as the dispersant, and water as the solvent. Mechanism analysis: Optical shielding: single-walled carbon nanotubes have strong light absorption ability, which can effectively absorb and scatter ultraviolet and visible light, reduce the light transmittance of the membrane material to below 5%, and realize high-efficiency light shielding. Conductive performance: the conductivity of carbon nanotubes makes the functional layer have certain electrical conductivity, which can disperse static electricity and avoid particle adsorption and membrane damage caused by static electricity accumulation, improving the stability of the membrane. Structural uniformity: through ultrasonic dispersion technology, carbon nanotubes are uniformly dispersed in the PVA matrix, avoiding agglomeration and ensuring the uniformity of optical and conductive properties. Catalytic reduction assistance: nickel nitrate hexahydrate promotes the structure optimization of carbon nanotubes and the formation of conductive network during high-temperature reduction, enhancing the functionality of the membrane layer. Three-layer sandwich structure design: structure composition: silicon dioxide nanofiber membrane / light shielding and conductive functional layer / silicon dioxide nanofiber membrane. Mechanism analysis: Functional complementarity: the outer and inner silicon dioxide nanofiber membranes provide mechanical protection and thermal insulation barrier, and the middle functional layer realizes high-efficiency light shielding and conductive dispersion, and the three-layer structure considers thermal insulation, light shielding and mechanical strength. Interface bonding: through scraping technology and pressure (0.1-0.5MPa), the tight bonding between layers is realized, reducing the interface thermal resistance and light transmission path, and improving the overall performance. Stability improvement: the sandwich structure avoids direct exposure of the functional layer, reduces environmental oxidation and mechanical wear, and prolongs the service life of the membrane material.Key process parameters influence mechanism on performance: Electrospinning parameters: voltage (12-18 kV), collection distance (8-12 cm), and feed rate (0.8-1.2 mL / h) affect fiber diameter and uniformity, which in turn affect the porosity and thermal conductivity of the membrane. Proper parameters ensure that the nanofibers are uniform and delicate, forming a high-porosity structure and reducing the thermal conductivity. Calcination temperature and time: Calcination temperature (700-900℃) and heating rate (3-5℃ / min) control the crystallinity and structural stability of the silica nanofibers. Too low a temperature leads to organic residues, affecting thermal stability and mechanical strength; too high a temperature may cause fiber sintering, reducing porosity and increasing thermal conductivity. Functional layer component ratio: Single-walled carbon nanotube content (5-15 parts, preferably 9wt%) directly affects the light-blocking effect and electrical conductivity. Insufficient content results in poor light-blocking effect; excessive content easily leads to agglomeration, affecting membrane uniformity and mechanical properties. Nickel nitrate hexahydrate concentration (0.2 mol / L) and ultrasonic dispersion time (1 h) ensure uniform dispersion of carbon nanotubes and catalytic reduction effect, optimizing the conductive network. Coating thickness and pressure: The coating thickness is controlled at 5-20 μm, too thin affecting the light-blocking effect, too thick affecting the flexibility and cost. The pressure (0.1-0.5 MPa) ensures tight interlayer bonding, reduces interface defects, and improves mechanical strength and thermal resistance. High-temperature carbonization reduction process: Carbonization temperature (250-350℃) and reduction temperature (650-750℃) are carried out under argon protection, removing organic components, promoting carbon nanotube structure optimization and the formation of a conductive network in the functional layer. This process ensures the chemical stability and mechanical properties of the membrane material, preventing oxidative damage. Performance testing and mechanism verification: Visible light transmittance: less than 5%, indicating that the functional layer effectively absorbs and blocks light, preventing photolysis reactions. UV shielding rate: more than 99%, effectively preventing UV-induced chemical degradation. Thermal conductivity: less than 0.045 W / m·K, ensuring thermal insulation performance and preventing high temperature from accelerating drug degradation. The comparative experiment shows that the lack of key steps (such as carbonization reduction, carbon nanotube addition, and sandwich structure) significantly reduces performance, verifying the necessity of each process link and material ratio. In summary, the light-blocking and heat-insulating film material of the present invention realizes the following technical mechanisms through nanostructure design and functional composite: Optical mechanism: The strong light absorption and scattering of single-walled carbon nanotubes, combined with the multi-layer sandwich structure, form a high-efficiency light barrier, blocking UV and visible light, and preventing potassium chloride particle preparations from photolysis. Thermal mechanism: The porous nanostructure of the silica nanofiber membrane greatly reduces heat conduction, forming a thermal insulation layer, maintaining the stability of the preparation temperature, and delaying heat-induced drug degradation and auxiliary material deterioration. Mechanical mechanism: The composite sandwich structure of the electrospun nanofiber membrane and the functional layer has good mechanical strength and flexibility, adapts to the packaging environment, and ensures the integrity of the membrane. Chemical stability mechanism: The high-temperature carbonization reduction process eliminates organic residues, optimizes the structure of carbon nanotubes, and improves the chemical inertness and durability of the membrane material, avoiding direct contact with potassium chloride particles, ensuring drug safety.Controllable mechanism: Through accurate control of electrospinning, electrolyte ratio, coating thickness and heat treatment parameters, the stability and adjustability of the film material performance are realized to meet the needs of different storage environments.

[0046] In summary, through material innovation and process optimization, the technical scheme constructs a high-efficiency, stable and economical potassium chloride particle preparation light-proof heat insulation film material, significantly improves the storage safety and shelf life of the drug, and has important application value and popularization prospect.

[0047] The above series of detailed descriptions are only specific descriptions of the feasible embodiments of the present application, and are not used to limit the protection scope of the present application. Any equivalent embodiments or changes made without departing from the spirit of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a light-shielding and heat-insulating film material for a potassium chloride granule preparation, characterized in that: The method comprises the following steps: (1) preparing a heat-insulating base film layer: mixing tetraethyl orthosilicate, water and oxalic acid in a molar ratio of 1:8:0.018, stirring at room temperature for 8 to 12 hours to form a silica precursor sol; mixing polyvinyl alcohol and water in a mass ratio of 1:9 to prepare a 10 wt% PVA solution; mixing the two in a mass ratio of 1:1 and stirring for 8 to 10 hours to obtain a spinnable solution, and performing electrospinning treatment; then heating to 700 to 900°C in a tubular furnace at a rate of 3 to 5°C / min and calcining for 1 to 3 hours to obtain a silica nanofiber membrane with a thermal conductivity coefficient lower than 0.05 W / m·K; (2) preparing a light-shielding conductive functional layer solution: by weight, 5 to 10 parts by weight of single-walled carbon nanotubes; 5 parts, 50-80 parts of PVA, 2-10 parts of nickel nitrate hexahydrate, 0.5-2 parts of sodium dodecyl sulfate, and 30-60 parts of deionized water are mixed and ultrasonically dispersed and then stirred evenly; (3) Construction of composite membrane: Scrape the functional layer solution onto the silica nanofiber membrane with a coating thickness of 5-20 μm, and cover it with another layer of silica nanofiber membrane to form a sandwich structure; (4) High-temperature carbonization reduction: Carbonization at 250-350℃ for 1-2h under argon protection, and reduction at 650-750℃ for 1-2h; (5) Post-processing inspection: Cut and ensure that the visible light transmittance is less than 5%, the ultraviolet shielding rate is greater than 99%, and the thermal conductivity is less than 0.045W / m·K; In the step (1), the average fiber diameter of the silica nanofiber membrane is controlled at 280 to 400 nm, and the electrospinning treatment condition is a voltage of 12 to 18 kV.

2. The method for preparing the light-shielding and heat-insulating film material for potassium chloride granules according to claim 1, wherein: The content of single-walled carbon nanotubes in step (2) is preferably 9 wt%.

3. The method for preparing the light-shielding and heat-insulating film material for potassium chloride granules according to claim 1, wherein: In step (2), the concentration of nickel nitrate hexahydrate solution is 0.2 mol / L, and the ultrasonic dispersion time is 1 h.

4. The method for preparing the light-shielding and heat-insulating film material for potassium chloride granules according to claim 1, wherein: The preparation method of the sandwich structure in step (3) is as follows: using a scraping technique, the light-shielding conductive functional layer solution prepared in step (2) is evenly coated on the surface of the silica nanofiber membrane prepared in step (1), and the coating thickness is controlled to be 5 to 20 μm; then another layer of silica nanofiber membrane is covered on the coating surface, and a three-layer sandwich structure of silica / conductive layer / silicon dioxide is formed by applying pressure.

5. The method for preparing the light-shielding and heat-insulating film material for potassium chloride granules according to claim 4, wherein: The pressure applied in step (3) is 0.1 to 0.5 MPa.

6. The method for preparing the light-shielding and heat-insulating film material for potassium chloride granules according to claim 1, wherein: In step (1), the collection distance is 8 to 12 cm, and the feed rate is 0.8 to 1.2 mL / h.

7. The method for preparing the light-shielding and heat-insulating film material for potassium chloride granules according to claim 1, wherein: In step (4), the carbonization temperature is 300°C and the reduction temperature is 700°C.

8. The light-shielding and heat-insulating film material obtained by the preparation method according to claim 1.

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