High-temperature sterilization sterile barrier packaging material

Abstract

The invention relates to the technical field of packaging materials, in particular to a high-temperature sterilization sterile barrier packaging material which comprises a breathable base material, and a micron fiber supporting layer, a nano fiber barrier layer and a reentry structure surface layer which are sequentially attached to the surface of the breathable base material. A solution rotor spinning technology is adopted, so that a microorganism seepage path is cut off while efficient ventilation is ensured; and a bead-like reentry structure is constructed on the surface, so that the material is endowed with excellent super-hydrophobic anti-wetting performance. The invention solves the technical problems that the existing sterile packaging material is difficult to give consideration to ventilation and barrier in a high-temperature steam sterilization environment, is easy to deform due to thermal shrinkage and is easy to wet.

Description

Technical Field

[0001] This invention relates to the field of packaging materials technology, and in particular to a high-temperature sterilization aseptic barrier packaging material. Background Technology

[0002] In the field of modern medical devices, aseptic barrier systems are a crucial line of defense ensuring the sterility of medical devices from sterilization until use. Among various sterilization methods, high-temperature, high-pressure steam sterilization is widely used due to its non-toxicity, environmental friendliness, and strong penetrating power. However, this sterilization method operates under extremely harsh conditions, requiring packaging materials to possess dual functions: sufficient permeability to allow the rapid entry and exit of the sterilization medium (steam) and to balance the enormous pressure difference generated during the pulsating vacuum phase, preventing packaging rupture; and a dense microporous structure to absolutely block the invasion of microorganisms. Furthermore, the material must withstand high-temperature thermal shock and high-humidity environments to prevent thermal deformation or bacterial penetration due to condensation.

[0003] Currently, commonly used medical packaging materials in clinical practice mainly include medical dialysis paper and flash-processed polyethylene materials. While medical dialysis paper has a lower cost, its mechanical strength decreases significantly when wet and it is prone to generating microfiber particles, posing a risk to cleanliness. Although flash-processed polyethylene materials have excellent overall performance, their production process is extremely complex, requiring significant equipment investment. Furthermore, their melting point is close to the upper limit of high-temperature steam sterilization, posing a risk of thermal shrinkage or dimensional deformation under prolonged or extreme high-temperature sterilization procedures, potentially compromising the integrity of the sterile barrier.

[0004] In recent years, nanofiber membranes have been considered ideal microbial barrier materials due to their high specific surface area and tortuous pore channels. However, the mainstream technology for preparing nanofibers—electrospinning—faces many bottlenecks in industrial applications. Electrospinning relies on a high-voltage electric field, posing safety hazards for systems using flammable organic solvents; the technology is sensitive to the conductivity of the polymer solution, limiting the application of some high-performance polymers; most importantly, the yield per electrospinning nozzle is extremely low, making it difficult to meet the high-throughput production demands of bulk packaging materials.

[0005] Furthermore, in terms of material structure design, existing porous media often struggle to balance the contradictory parameters of "high air permeability" and "high barrier properties." While uniform and dense nanofiber layers can effectively block bacteria, excessive fluid resistance can easily lead to pressure residues and packaging damage during sterilization. Simultaneously, existing materials lack targeted anti-wetting designs on their surfaces, making them prone to wetting when exposed to steam condensation, resulting in "wet packs" and increasing the risk of bacteria penetrating the barrier through liquid bridges.

[0006] Therefore, we propose a high-temperature sterilization aseptic barrier packaging material to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by proposing a high-temperature sterilization aseptic barrier packaging material.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A high-temperature sterilization aseptic barrier packaging material includes a breathable substrate and a microfiber support layer, a nanofiber barrier layer and a re-entry structure surface layer sequentially attached to its surface.

[0009] As a preferred technical solution: The high-temperature sterilization aseptic barrier packaging material described above is prepared by a process comprising the following steps: Step S1: Select polyvinylidene fluoride-hexafluoropropylene as the matrix resin, dissolve it in a mixed solvent of N,N-dimethylformamide and acetone, and prepare high-concentration spinning solutions, medium-concentration spinning solutions and low-concentration spinning solutions respectively. Step S2: Place the breathable substrate on the receiving device, and use the solution airflow spinning process to spray the high-concentration spinning solution obtained in step S1 onto the surface of the breathable substrate under low air pressure conditions to form a micron fiber support layer with an average diameter of 1-3µm. Step S3: Under high pressure, the medium-concentration spinning solution obtained in step S1 is sprayed onto the surface of the micron fiber support layer obtained in step S2 to form a nanofiber barrier layer with an average diameter of 100-200 nm. Step S4: Spray the low-concentration spinning solution obtained in step S1 onto the surface of the nanofiber barrier layer obtained in step S3 to induce the formation of beaded fibers and form a surface layer with a re-entry structure, thereby obtaining an uncrosslinked composite film. Step S5: Place the uncrosslinked composite film obtained in step S4 under an electron beam accelerator and subject it to electron beam irradiation treatment with a dose of 50-80 kGy to form a crosslinked network of PVDF-HFP molecular chains in the film layer, thereby obtaining a high-temperature sterilization aseptic barrier packaging material.

[0010] In the high-temperature sterilization aseptic barrier packaging material described above, the average fiber diameter of the microfiber support layer is 1-3µm; the average fiber diameter of the nanofiber barrier layer is 100-200nm; and the thickness of the nanofiber barrier layer is 20-30µm.

[0011] As described above, in a high-temperature sterilization aseptic barrier packaging material, the fibers of the re-entry structure surface layer have a beaded morphology and are composed of microspheres strung together on nanofibers. Furthermore, the water contact angle of the re-entry structure surface layer is greater than 150° and the roll-off angle is less than 10°.

[0012] In the high-temperature sterilization aseptic barrier packaging material described above, in step S1, the concentration of the high-concentration spinning solution is 18 wt%, the concentration of the medium-concentration spinning solution is 14 wt%, and the concentration of the low-concentration spinning solution is 10-12 wt%; in step S2, the low-pressure condition is 0.1 MPa; and in step S3, the high-pressure condition is 0.5-0.6 MPa.

[0013] In the high-temperature sterilization aseptic barrier packaging material described above, in step S1, the weight-average molecular weight of the polyvinylidene fluoride-hexafluoropropylene is greater than 400,000; the volume ratio of N,N-dimethylformamide to acetone in the mixed solvent is 6:4; and the spinning solution also contains the polyfunctional monomer TAIC as a sensitizer.

[0014] The high-temperature sterilization aseptic barrier packaging material described above has an area shrinkage rate of less than 2% after being treated in a saturated steam environment at 135°C for 30 minutes.

[0015] The high-temperature sterilization aseptic barrier packaging material described above employs a multi-stage series SBS spraying system. In steps S2 to S4, the breathable substrate moves within the multi-stage series SBS spraying system, sequentially passing through different spraying areas, thereby achieving the continuous deposition of the microfiber support layer, the nanofiber barrier layer, and the re-entry structure surface layer.

[0016] As described above, in a high-temperature sterilization aseptic barrier packaging material, the electron beam irradiation treatment in step S5 is carried out in an oxygen-free or controlled atmosphere; the crosslinking network is a CC covalent bond network formed by the breakage of CH and CF bonds on the PVDF-HFP molecular chain under irradiation to generate free radicals, and then the combination of adjacent molecular chains.

[0017] The mechanism of this invention is as follows: by combining the PVDF-HFP molecular chain CC bond cross-linking network induced by electron beam irradiation, the dimensional stability of 135℃ high-temperature steam sterilization is ensured while achieving a balance between high-flux air permeability, absolute microbial barrier and superhydrophobic antiwetting properties. Beneficial effects: By inducing the PVDF-HFP molecular chains to form a CC covalent cross-linking network under the action of high-energy electron beam, the thermal motion of the amorphous region chain segments is restricted, resulting in an area shrinkage rate of less than 2% after the material is treated in a saturated steam environment at 135℃ for 30 minutes. This eliminates the risk of thermal deformation or embrittlement of traditional materials at extreme sterilization temperatures, and significantly improves the safety of medical packaging. The large-pore support layer significantly reduces the physical resistance to airflow, while the dense nano barrier layer cuts off the penetration path of microorganisms based on the permeation theory. While ensuring absolute microbial barrier, it significantly improves air permeability and effectively balances the internal and external pressure difference during the pulsed vacuum sterilization process, greatly reducing the risk of packaging bags breaking due to pressure fluctuations.

[0018] Utilizing the Rayleigh instability principle, a beaded reentry structure was constructed in situ on the material surface, endowing the material with excellent superhydrophobic properties and anti-condensation and wetting ability. This prevents condensate from spreading or penetrating on the material surface, thus preventing bacterial penetration caused by liquid bridges formed by condensate during sterilization. It also ensures that the packaging can maintain good air permeability and dryness in humid environments, avoiding the common problem of wet packaging in clinical practice. Attached Figure Description

[0019] Figure 1 A schematic diagram of the preparation of the micron-fiber support layer by the solution airflow spinning process of the present invention; Figure 2 This is a schematic diagram illustrating the preparation of the nanofiber barrier layer using the solution airflow spinning process of the present invention. Detailed Implementation

[0020] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the definitions in this specification shall prevail. When a mass, concentration, temperature, time, or other value or parameter is expressed as a range, preferred range, or a series of upper and lower preferred values, this shall be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether such range is disclosed individually. For example, a range of 1-50 should be understood to include selections from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 3 Any number, combination of numbers, or subrange of numbers between the integers 6, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50, and all decimal values ​​between the integers listed above, such as 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, and 1.9. Regarding subranges, specifically consider “nested subranges” extending from any endpoint of the range. For example, nested subranges of the exemplary range 1-50 could include 1-10, 1-20, 1-30, and 1-40 in one direction, or 50-40, 50-30, 50-20, and 50-10 in another direction. The present invention will be further explained below with reference to specific embodiments. Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials can be obtained commercially.

[0021] A high-temperature sterilization aseptic barrier packaging material includes a breathable substrate and a microfiber support layer, a nanofiber barrier layer and a re-entry structure surface layer sequentially attached to its surface.

[0022] This high-temperature sterilization aseptic barrier packaging material is prepared through a process including the following steps: Step S1: Select polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) as the matrix resin, dissolve it in a mixed solvent of N,N-dimethylformamide (DMF) and acetone, and prepare high-concentration spinning solutions, medium-concentration spinning solutions and low-concentration spinning solutions respectively. Step S2: Place the breathable substrate on the receiving device and use the solution air-jet spinning (SBS) process to spray the high-concentration spinning solution obtained in step S1 onto the surface of the breathable substrate under low air pressure conditions to form a micron fiber support layer with an average diameter of 1-3µm. Step S3: Using solution air-jet spinning (SBS) technology, the medium-concentration spinning solution obtained in step S1 is sprayed onto the surface of the micron fiber support layer obtained in step S2 under high pressure conditions to form a nanofiber barrier layer with an average diameter of 100-200 nm. Step S4: Using the solution air-spinning (SBS) process, the low-concentration spinning solution obtained in step S1 is sprayed onto the surface of the nanofiber barrier layer obtained in step S3. The Rayleigh instability principle is used to induce the generation of beaded fibers, forming a surface layer with a re-entry structure, thereby obtaining an uncrosslinked composite film. Step S5: Place the uncrosslinked composite film obtained in step S4 under an electron beam accelerator and subject it to electron beam irradiation treatment with a dose of 50-80 kGy to form a crosslinked network of PVDF-HFP molecular chains in the film layer, thereby obtaining a high-temperature sterilization aseptic barrier packaging material.

[0023] Specifically, the average fiber diameter of the microfiber support layer is 1-3µm; the average fiber diameter of the nanofiber barrier layer is 100-200nm, and the thickness of the nanofiber barrier layer is 20-30µm.

[0024] Specifically, the fibers in the re-entry structure surface layer have a beaded morphology, consisting of microspheres strung together on nanofibers, and the water contact angle of the re-entry structure surface layer is greater than 150° and the roll-off angle is less than 10°.

[0025] Specifically, in step S1, the concentration of the high-concentration spinning solution is 18 wt%, the concentration of the medium-concentration spinning solution is 14 wt%, and the concentration of the low-concentration spinning solution is 10-12 wt%; in step S2, the low-pressure condition is 0.1 MPa; and in step S3, the high-pressure condition is 0.5-0.6 MPa.

[0026] Specifically, in step S1, the weight-average molecular weight (Mw) of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) is greater than 400,000; the volume ratio of N,N-dimethylformamide (DMF) to acetone in the mixed solvent is 6:4; and the spinning solution also contains the polyfunctional monomer TAIC as a sensitizer.

[0027] Specifically, the area shrinkage rate of the high-temperature sterilized aseptic barrier packaging material after being treated in a saturated steam environment at 135°C for 30 minutes is less than 2%.

[0028] Specifically, the process employs a multi-stage series SBS spraying system; in steps S2 to S4, the breathable substrate moves within the multi-stage series SBS spraying system, sequentially passing through different spraying areas, thereby achieving the continuous deposition of the micron fiber support layer, the nanofiber barrier layer, and the re-entry structure surface layer.

[0029] Specifically, the electron beam irradiation treatment in step S5 is carried out in an oxygen-free or controlled atmosphere; the cross-linking network is a CC covalent bond network formed by the breakage of CH and CF bonds on the PVDF-HFP molecular chain under irradiation to generate free radicals, which in turn combine with adjacent molecular chains.

[0030] Example, refer to Figure 1 and Figure 2 General preparation conditions: Raw materials: Polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP, weight average molecular weight Mw=450000, Arkema Kynar Flex series); solvent: a mixture of N,N-dimethylformamide (DMF) and acetone (volume ratio 6:4); sensitizer: triallyl isocyanurate (TAIC).

[0031] Substrate: Medical dialysis paper is selected as the breathable substrate.

[0032] Equipment: Multistage series solution airflow spinning (SBS) system, electron beam irradiation accelerator.

[0033] Example 1: The fully structured sterile barrier material of the present invention: Step 1 (Solution Preparation): Solution A (high concentration): PVDF-HFP is dissolved in a mixed solvent at a concentration of 18 wt%.

[0034] Solution B (medium concentration): PVDF-HFP is dissolved in a mixed solvent to a concentration of 14 wt%.

[0035] Solution C (low concentration): Dissolve PVDF-HFP in a mixed solvent to a concentration of 10 wt%, and add 1 wt% TAIC.

[0036] Step 2 (Preparation of the micron-sized support layer): Solution A is sprayed using an SBS nozzle. Process parameters: air pressure 0.1 MPa, receiving distance 20 cm. A micron-sized fiber layer with an average diameter of 2.5 µm is formed on the substrate.

[0037] Step 3 (Preparation of the nano-barrier layer): Solution B is sprayed using an SBS nozzle to cover the support layer. Process parameters: gas pressure 0.6 MPa, receiving distance 30 cm. A dense nanofiber layer with an average diameter of 150 nm and a thickness of approximately 25 µm is formed.

[0038] Step 4 (Re-entry Surface Layer Preparation): Solution C is sprayed using an SBS nozzle. Process parameters: gas pressure 0.2 MPa, solution flow rate slightly higher to induce Rayleigh instability. This forms a fiber layer with a large number of beaded structures.

[0039] Step 5 (irradiation crosslinking): Place the above composite film under a nitrogen-protected electron beam accelerator, and set the radiation dose to 65 kGy.

[0040] Example 2: Sterile barrier material with adjustable parameters: The only difference from Example 1 was the fine-tuning of process parameters to verify feasibility within the specified range: the concentration of solution B was adjusted to 14.5 wt%, and the gas pressure was adjusted to 0.5 MPa (resulting in a fiber diameter of approximately 180 nm). The radiation dose was adjusted to 50 kGy. The remaining steps were consistent with Example 1.

[0041] Set the following comparison scale: Comparative Example 1: Untreated with radiation crosslinking (to verify temperature resistance) The preparation process is exactly the same as in Example 1 (steps 1-4), but the electron beam irradiation treatment in step 5 is not performed.

[0042] This sample represents an unmodified conventional PVDF-HFP nanofiber membrane.

[0043] Comparative Example 2: No composite structure (verifying the law of breathability and configuration) No micron-sized support layer or re-entry surface layer is prepared.

[0044] Solution B (14wt%) was directly applied to the substrate for an extended period of time to achieve the same thickness as the total weight in Example 1.

[0045] Crosslinking was performed using 65 kGy irradiation.

[0046] This sample represents a traditional single-scale dense nanofiber membrane.

[0047] Comparative Example 3: Non-reentrant surface layer (verification of anti-wetting properties) The preparation process is the same as in Example 1, but step 4 is omitted (low-concentration solution C is not sprayed, and there is no beaded structure).

[0048] The "support layer + barrier layer" were directly cross-linked by 65 kGy irradiation.

[0049] The sample surface is composed of smooth nanofibers without any microscopic geometric chamfers.

[0050] The following performance tests were performed on the materials obtained in the above embodiments and comparative examples: High-temperature heat shrinkage rate: Cut the sample into 10cm×10cm pieces, place them in a 135℃ saturated steam sterilizer for 30 minutes, and measure the area change before and after treatment.

[0051] Calculation formula: ; Air permeability (Gurley value): measures the time (seconds / 100cc) required for 100cc of air to flow through a 1 square inch sample. The smaller the value, the better the air permeability.

[0052] Bacterial filtration efficiency (BFE): Tested using Staphylococcus aureus aerosol (ASTM F2101), with a target of Log 6 level.

[0053] Surface wettability: Measure the water contact angle (WCA) and roll-off angle (SA).

[0054] The performance test data of the examples and comparative examples are shown in Table 1 below: Table 1

[0055] Referring to Table 1 above, the key aspect of crosslinking (Example 1 vs. Comparative Example 1): Data from Comparative Example 1 shows that the PVDF-HFP film without electron beam irradiation experienced severe shrinkage of up to 38.5% at 135°C. This is due to stress release caused by the movement of chain segments in the amorphous regions. In contrast, Example 1, after irradiation with 65 kGy, formed a CC crosslinked network, controlling the shrinkage rate to 1.2%, thus meeting the dimensional stability requirements for high-temperature steam sterilization.

[0056] Comparative Example 2 used single-scale nanofibers, which met the filtration efficiency requirements, but its Gurley value was as high as 120s, indicating extremely high flow resistance. During the pulsed vacuum sterilization process, the extremely high pressure drop could cause the packaging to rupture. In contrast, Example 1 used a "micron-support-nano barrier" structure designed according to the law of configuration, which reduced the Gurley value to 15s while maintaining the same barrier properties, achieving a balance between high permeability and high barrier properties.

[0057] Although Comparative Example 3 used the hydrophobic material PVDF, its surface was made of smooth fibers, resulting in a contact angle of only 118° (typical hydrophobicity). Example 1 constructed a beaded re-entry structure using a low-concentration SBS process, increasing the contact angle to 154° and achieving an extremely low roll-off angle. This effectively prevents condensate from forming a liquid film that clogs the pores or permeates through capillary action, thus avoiding wet-packing.

[0058] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-temperature sterilization aseptic barrier packaging material, characterized in that, It includes a breathable substrate and a microfiber support layer, a nanofiber barrier layer and a re-entry structure surface layer sequentially attached to its surface.

2. The high-temperature sterilization aseptic barrier packaging material according to claim 1, characterized in that, The high-temperature sterilization aseptic barrier packaging material is prepared by a process including the following steps: Step S1: Select polyvinylidene fluoride-hexafluoropropylene as the matrix resin, dissolve it in a mixed solvent of N,N-dimethylformamide and acetone, and prepare high-concentration spinning solutions, medium-concentration spinning solutions and low-concentration spinning solutions respectively. Step S2: Place the breathable substrate on the receiving device, and use the solution airflow spinning process to spray the high-concentration spinning solution obtained in step S1 onto the surface of the breathable substrate under low air pressure conditions to form a micron fiber support layer with an average diameter of 1-3µm. Step S3: Under high pressure, the medium-concentration spinning solution obtained in step S1 is sprayed onto the surface of the micron fiber support layer obtained in step S2 to form a nanofiber barrier layer with an average diameter of 100-200 nm. Step S4: Spray the low-concentration spinning solution obtained in step S1 onto the surface of the nanofiber barrier layer obtained in step S3 to induce the formation of beaded fibers and form a surface layer with a re-entry structure, thereby obtaining an uncrosslinked composite film. Step S5: Place the uncrosslinked composite film obtained in step S4 under an electron beam accelerator and subject it to electron beam irradiation treatment with a dose of 50-80 kGy to form a crosslinked network of PVDF-HFP molecular chains in the film layer, thereby obtaining a high-temperature sterilization aseptic barrier packaging material.

3. The high-temperature sterilization aseptic barrier packaging material according to claim 1, characterized in that, The average diameter of the microfiber support layer is 1-3µm; the average diameter of the nanofiber barrier layer is 100-200nm, and the thickness of the nanofiber barrier layer is 20-30µm.

4. The high-temperature sterilization aseptic barrier packaging material according to claim 1, characterized in that, The fibers of the re-entry structure surface layer have a beaded morphology and are composed of microspheres strung together on nanofibers. The water contact angle of the re-entry structure surface layer is greater than 150° and the roll-off angle is less than 10°.

5. The high-temperature sterilization aseptic barrier packaging material according to claim 2, characterized in that, In step S1, the concentration of the high-concentration spinning solution is 18 wt%, the concentration of the medium-concentration spinning solution is 14 wt%, and the concentration of the low-concentration spinning solution is 10-12 wt%. In step S2, the low pressure condition is a pressure of 0.1 MPa; In step S3, the high-pressure condition is a pressure of 0.5-0.6 MPa.

6. The high-temperature sterilization aseptic barrier packaging material according to claim 2, characterized in that, In step S1, the weight-average molecular weight of the polyvinylidene fluoride-hexafluoropropylene is greater than 400,000. The volume ratio of N,N-dimethylformamide to acetone in the mixed solvent is 6:4; and the spinning solution also contains the polyfunctional monomer TAIC as a sensitizer.

7. The high-temperature sterilization aseptic barrier packaging material according to claim 1, characterized in that, The area shrinkage rate of the high-temperature sterilized aseptic barrier packaging material after treatment in a saturated steam environment at 135°C for 30 minutes is less than 2%.

8. The high-temperature sterilization aseptic barrier packaging material according to claim 2, characterized in that, The process employs a multi-stage tandem SBS spraying system; In steps S2 to S4, the breathable substrate moves within the multi-stage series SBS spraying system, sequentially passing through different spraying areas, thereby achieving the continuous deposition of the microfiber support layer, the nanofiber barrier layer, and the re-entry structure surface layer.

9. The high-temperature sterilization aseptic barrier packaging material according to claim 2, characterized in that, The electron beam irradiation process described in step S5 is carried out in an oxygen-free or controlled atmosphere; The cross-linking network is a CC covalent bond network formed by the breakage of CH and CF bonds on the PVDF-HFP molecular chain under irradiation to generate free radicals, which in turn combine with adjacent molecular chains.

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