A bag-making, filling and sealing method and integrated equipment for double non-PVC film

Abstract

This invention relates to the field of pharmaceutical packaging technology, and discloses a method and integrated equipment for bag making and sealing using double non-PVC films. The method includes the following steps: The non-PVC film is introduced into a forming station to form a bag body and then filled with liquid medicine; the bag body is transferred to a heat-sealing station A, where a moving mold heat-sealing knife and a stationary mold heat-sealing knife close and clamp the bag body to be sealed, applying initial mechanical pressure, and executing a pressure step command to reduce the pressure to the critical heat transfer pressure; the moving mold heat-sealing knife and the stationary mold heat-sealing knife open, transferring the bag body to a cooling station B; during the bag body transfer process and after the bag body reaches the cooling station B, a damping tension roller applies longitudinal mechanical tensile tension to the bag body's sealing area; the cold pressing block at the cooling station B closes and clamps the bag body's sealing area, applying a holding pressure; the cold pressing block opens and releases the longitudinal mechanical tensile tension to complete the bag making and sealing process. This invention prevents weakened areas from forming at the bag body's sealing edge, improving heat-sealing strength and the flatness of the bag body's sealing area.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical packaging technology, specifically to a method and integrated equipment for making and sealing bags using double non-PVC film. Background Technology

[0002] Non-PVC film, used as a pharmaceutical packaging material, requires a bag-making and sealing process to form a bag to hold the liquid medicine. In the existing non-PVC film bag-making and sealing process, the heat-sealing station uses constant mechanical pressure to clamp and heat the area of ​​the non-PVC film to be sealed. During heat transfer, the inner layer of the non-PVC film gradually reaches a molten state. The continuous constant mechanical pressure excessively compresses the inner polymer material in its high-temperature molten state, causing the inner polymer material to overflow outwards from the heat-sealed area. This results in a weakened area at the sealing edge, reducing the structural strength of the bag's sealing area. During the cooling and crystallization stage after heat sealing, the polymer material generates volume shrinkage stress, causing thermal shrinkage deformation and stress concentration in the bag's sealing area, leading to poor bag seal flatness and wrinkles.

[0003] When the bag, after being filled and sealed, undergoes terminal sterilization in a pulsed vacuum autoclave, the liquid medicine inside the bag expands due to heat, generating internal pressure. If an external counterpressure matching this internal pressure is not established to counteract it, the bag may deform or even crack under high-temperature softening conditions. Furthermore, during the extrusion molding stage, the polymer material in non-PVC films is susceptible to thermal oxidation degradation and chain breakage due to heat and shear. The crystalline structure of polypropylene in conventional formulations easily causes light scattering, reducing the light transmittance of non-PVC films. Moreover, the inner layer material of conventional non-PVC films has limited ability to absorb impact energy, making bags filled with liquid medicine prone to breakage upon physical impact, and their drop resistance cannot meet the practical application requirements of production and transportation. Therefore, this invention proposes a bag-making and filling method and integrated equipment using dual non-PVC films to address the shortcomings of existing technologies. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a bag-making and sealing method and integrated equipment using double non-PVC films. This solves the problems of molten material overflowing from the inner layer of the non-PVC film and creating a weakened area at the sealing edge due to continuous application of constant mechanical pressure during the heat-sealing process, as well as thermal shrinkage deformation and poor flatness in the bag sealing area caused by volume shrinkage stress generated by the polymer material during the cooling and crystallization stage.

[0005] To achieve the above objectives, the present invention provides a bag-making and sealing method using double non-PVC film, comprising the following steps:

[0006] The non-PVC film is introduced into the forming station for forming to obtain the bag body, and the filling pump is started to fill the bag body with the medicine liquid.

[0007] The bag that has been filled with medicine is transferred to heat sealing station A. The moving mold heat sealing knife and the stationary mold heat sealing knife of heat sealing station A are driven to close the area of ​​the bag to be sealed, apply initial mechanical pressure, and maintain it for the first time period.

[0008] Maintain the closed state of the moving mold heat sealing knife and the stationary mold heat sealing knife, execute the pressure step command, reduce the mold closing pressure from the initial mechanical pressure to the critical heat transfer pressure, and maintain it for the second time period;

[0009] The moving mold heat sealing knife and the stationary mold heat sealing knife are opened to transfer the bag body to the cooling station B. During the transfer of the bag body and after the bag body arrives at the cooling station B, longitudinal mechanical tensile tension is applied to the sealing area of ​​the bag body through the damping tension roller.

[0010] The cold pressing block at cooling station B closes and clamps the bag sealing area, applies pressure, and maintains it for the third time period.

[0011] The cold pressing block is opened, and the damping tension roller releases the longitudinal mechanical tensile tension, completing the bag making and sealing process.

[0012] By adopting the above technical solution, the pressure step command combining initial mechanical pressure and critical heat transfer pressure, along with the application of longitudinal mechanical tensile tension combined with cold pressing and shaping, achieves the effect of improving sealing strength and flatness. The specific mechanism is as follows:

[0013] Step 1: Close the moving mold heat sealing knife and the stationary mold heat sealing knife and apply initial mechanical pressure to make the non-PVC film to be sealed area adhere, expel the air between the non-PVC film layers, and establish the initial heat conduction channel.

[0014] Step 2: Execute the pressure step command to reduce the critical heat transfer pressure. While maintaining the continuous transfer of heat to the inner layer of the non-PVC film, reduce the probability of the polymer material in the inner layer of the non-PVC film in the high-temperature molten state being over-compressed and overflowing outward, and prevent the formation of a weakened area at the sealing edge.

[0015] Step 3: Apply longitudinal mechanical tensile tension to the sealing area of ​​the bag through the damping tension roller, so that the polymer chain segments in the semi-molten state are oriented along the direction of force to counteract the volume shrinkage stress generated during the polymer cooling and crystallization process.

[0016] Step four: Apply holding pressure with the cold pressing block at cooling station B to rapidly cool and solidify the bag sealing area where the polymer chain segments have been oriented under stress, thereby fixing the orientation structure of the polymer chain segments and eliminating the internal stress in the bag sealing area.

[0017] Preferably, the constant temperature of the moving mold heat sealing knife is set to 155℃~165℃; the constant temperature of the stationary mold heat sealing knife is set to 125℃~132℃; and the surface temperature of the cold pressing block is set to 15℃~25℃. The initial mechanical pressure is 0.50MPa~0.65MPa, and the first time period is 0.10s~0.15s; the critical heat transfer pressure is 0.22MPa~0.32MPa, and the second time period is 0.35s~0.55s; the holding pressure is 0.65MPa~0.85MPa, and the third time period is 0.40s~0.60s. The linear velocity for transferring the bag to the cooling station B is 150mm / s~250mm / s, and the longitudinal mechanical tensile tension is 3.0N~5.5N.

[0018] By employing the above technical solution, the set temperature and pressure parameters work synergistically to bring the inner layer of the non-PVC film to a molten state, while the middle support layer and the outer layer of the non-PVC film maintain solid support. The linear velocity and longitudinal mechanical tensile tension work together to maintain stable force on the bag during station transfer, preventing the non-PVC film from breaking or failing to align due to insufficient stretching.

[0019] Preferably, the non-PVC film comprises an inner layer, a middle support layer, and an outer layer; the inner layer is made of heat-sealing layer masterbatch, the middle support layer is made of homopolymer polypropylene, and the outer layer is made of polyethylene terephthalate-1,4-cyclohexanediol ester.

[0020] The heat-sealing masterbatch contains the following raw materials by weight percentage: 68.5wt%~75.0wt% random copolymer polypropylene, 24.65wt%~31.0wt% styrene-ethylene / butene-styrene block copolymer, 0.15wt%~0.35wt% 1,3:2,4-di(3,4-dimethylbenzyl)sorbitol, 0.075wt%~0.10wt% pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 0.075wt%~0.10wt% tris(2,4-di-tert-butylphenyl) phosphite.

[0021] By adopting the above technical solutions, random copolymer polypropylene provides sealing strength and structural stability; styrene-ethylene / butene-styrene block copolymer is dispersed as an elastomer in the random copolymer polypropylene matrix, absorbing interfacial impact energy and improving the flexibility and drop resistance of the inner layer; 1,3:2,4-di(3,4-dimethylbenzylene)sorbitol acts as a nucleating agent, providing heterogeneous nucleation sites, promoting the formation of small and uniform spherulitic structures in random copolymer polypropylene, reducing the scattering of light by crystals, and improving the light transmittance of non-PVC films; pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite are compounded to eliminate free radicals and hydroperoxides generated during processing, preventing thermal oxidative degradation and chain breakage of polymer chains.

[0022] Preferably, the preparation steps of the heat-sealing layer masterbatch include: adding random copolymer polypropylene, styrene-ethylene / butene-styrene block copolymer, 1,3:2,4-di(3,4-dimethylbenzyl)sorbitol, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and tris(2,4-di-tert-butylphenyl) phosphite into a high-speed mixer and mixing at 400-600 rpm for 5-8 minutes to obtain a mixture. The mixture is fed into a co-rotating twin-screw extruder for melt extrusion granulation. The feeding section temperature of the co-rotating twin-screw extruder is set to 160℃~175℃, the melting section temperature is set to 185℃~195℃, the homogenization section temperature is set to 205℃~215℃, and the screw speed is controlled at 300rpm~450rpm. After water ring pelletizing and drying, a heat-sealing layer masterbatch is obtained. The non-PVC film is produced using a three-layer co-extrusion casting process. The heat-sealing layer masterbatch, homopolymer polypropylene, and poly(1,4-cyclohexanedimethyl terephthalate) are co-extruded through a manifold die at a temperature of 220℃~230℃. The casting roll temperature is set to 20℃~25℃, resulting in a non-PVC film with a thickness of 180μm~220μm.

[0023] By adopting the above technical solution, the set temperature of each section of the extruder and the screw speed enable the components to be evenly dispersed under shearing action, eliminating macroscopic phase separation. The three-layer co-extrusion casting process enables the interfacial molecules of the inner layer, the middle support layer and the outer layer to become entangled in the molten state, forming a multi-layer structure and preventing interlayer delamination.

[0024] Preferably, after the bag is made and sealed, the process further includes placing the bag in a pulsed vacuum autoclave to perform a terminal sterilization procedure. The terminal sterilization procedure includes: performing 2 to 4 pulsed vacuum operations to purge the air from the pulsed vacuum autoclave; introducing high-temperature pure steam into the pulsed vacuum autoclave to raise the temperature to 120°C to 125°C within 10 to 20 minutes, maintaining a constant temperature sterilization state for 25 to 35 minutes, and maintaining the chamber pressure in the pulsed vacuum autoclave at 0.20 MPa to 0.25 MPa; after the constant temperature sterilization state is completed, spraying circulating cooling water into the pulsed vacuum autoclave for cooling treatment until the temperature in the pulsed vacuum autoclave drops to 35°C to 45°C.

[0025] By adopting the above technical solution, the pulsating vacuum operation replaces the cold air inside the pulsating vacuum high-pressure sterilizer, ensuring that high-temperature pure steam fully contacts the surface of the bag; maintaining a chamber pressure of 0.20MPa to 0.25MPa forms an external counterpressure that balances the internal pressure generated by the thermal expansion of the drug solution inside the bag, preventing the bag from bursting under the softened state at high temperature and maintaining the integrity of the bag.

[0026] Secondly, the present invention provides an integrated equipment for bag making and sealing of double non-PVC films, which adopts the following technical solution:

[0027] An integrated bag-making and sealing device for double non-PVC film includes a forming station, which receives the imported non-PVC film and performs forming processing to obtain the bag body.

[0028] A filling pump is used to fill the bag with liquid medicine.

[0029] Heat sealing station A includes a moving mold heat sealing knife, a stationary mold heat sealing knife, and a first servo cylinder. The first servo cylinder is used to drive the moving mold heat sealing knife and the stationary mold heat sealing knife to close and execute a pressure step command.

[0030] Damping tension rollers are used to apply longitudinal mechanical tensile tension to the sealing area of ​​a bag.

[0031] Cooling station B includes a cold pressing block and a second servo cylinder. The second servo cylinder is used to drive the cold pressing block to clamp and apply holding pressure.

[0032] Servo traction rollers are used to pull the bag body to the cooling station B.

[0033] By adopting the above technical solution, the first servo cylinder drives the moving mold heat sealing knife and the stationary mold heat sealing knife, thereby adjusting the mold closing pressure and performing a step switch from the initial mechanical pressure to the critical heat transfer pressure; the damping tension roller and the servo traction roller form a speed and torque match, outputting the set longitudinal mechanical tensile tension; the second servo cylinder provides a constant holding pressure, enabling each mechanical actuator to cooperate in completing the continuous bag making and sealing process.

[0034] This invention provides a method and integrated equipment for bag making and sealing using double non-PVC films. It offers the following advantages:

[0035] 1. This invention executes a pressure step command that reduces the initial mechanical pressure to the critical heat transfer pressure, thereby eliminating air between non-PVC film layers and preventing the molten material in the inner layer of the non-PVC film from overflowing outwards, thus avoiding the formation of a weakened area at the sealing edge. In conjunction with the damping tension roller, longitudinal mechanical tensile tension is applied to the sealing area of ​​the bag, causing the polymer chain segments to align and offset the volume shrinkage stress generated during the polymer cooling and crystallization process. Under the condition of holding pressure applied by the cold press block at the cooling station B, the bag is cooled and shaped, improving the flatness and heat seal strength of the sealing area.

[0036] 2. This invention utilizes a heat-sealing masterbatch, formulated from random copolymer polypropylene, styrene-ethylene / butene-styrene block copolymer, 1,3:2,4-di(3,4-dimethylbenzylene)sorbitol, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and tris(2,4-di-tert-butylphenyl) phosphite, as the inner layer raw material for the non-PVC film. The styrene-ethylene / butene-styrene block copolymer absorbs interfacial impact energy to improve the bag's drop resistance. 1,3:2,4-di(3,4-dimethylbenzylene)sorbitol promotes the formation of a uniform spherulitic structure in the random copolymer polypropylene, thereby improving the light transmittance of the non-PVC film. Combined with a three-layer co-extrusion casting process, the layers of the non-PVC film become intertwined in the molten state, preventing interlayer delamination.

[0037] 3. After the bag is made and sealed, the present invention performs a terminal sterilization procedure including a pulsed vacuum operation. The pulsed vacuum operation replaces the cold air inside the pulsed vacuum high-pressure sterilizer, ensuring that high-temperature pure steam contacts the surface of the bag. Under the constant temperature sterilization state of 120°C to 125°C, the chamber pressure is maintained at 0.20MPa to 0.25MPa, forming an external back pressure that balances the internal pressure generated by the thermal expansion of the medicine liquid inside the bag. This prevents the bag from bursting under the softened state of high temperature and maintains the integrity of the bag after the terminal sterilization procedure is completed. Attached Figure Description

[0038] Figure 1 This is a schematic diagram comparing the thickness retention rates of the present invention;

[0039] Figure 2 This is a schematic diagram of the macroscopic warpage index test of the bag body according to the present invention;

[0040] Figure 3 This is a schematic diagram comparing the mechanical properties and fracture modes of the T-shaped peel at the sealing interface of the present invention.

[0041] Figure 4 This is a schematic diagram comparing the bag breakage rate of the terminal pulsed vacuum high-temperature sterilization of the present invention. Detailed Implementation

[0042] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Embodiments of the present invention also provide an integrated bag-making and filling device for performing a bag-making and filling method for double non-PVC films, including a forming station, a filling pump, a heat-sealing station A, a servo traction roller, a damping tension roller, and a cooling station B.

[0044] The forming station receives the imported non-PVC film and forms it into a bag. The filling pump fills the bag with liquid medicine. The heat sealing station A is located downstream of the forming station. The heat sealing station A includes a moving mold heat sealing knife, a stationary mold heat sealing knife, and a first servo cylinder. The first servo cylinder drives the moving mold heat sealing knife and the stationary mold heat sealing knife to close and clamp the area of ​​the bag to be sealed and executes a pressure step command. The servo traction roller is used to pull the bag to the cooling station B. The damping tension roller applies longitudinal mechanical tensile tension to the sealing area of ​​the bag during the bag transfer process and after reaching the cooling station B. The cooling station B is located downstream of the heat sealing station A. The cooling station B includes a cold pressing block and a second servo cylinder. The second servo cylinder drives the cold pressing block to clamp the sealing area of ​​the bag and apply a holding pressure.

[0045] The specific collaborative operation process of the above hardware modules will be described in detail in the subsequent method embodiments.

[0046] Preparation Examples 1-3:

[0047] Preparation Example 1:

[0048] This preparation example provides a method for preparing a heat-sealing layer composition and a non-PVC film, including the following steps:

[0049] Weigh out 71.58 wt% of random copolymer polypropylene, 28.0 wt% of styrene-ethylene / butene-styrene block copolymer, 0.25 wt% of 1,3:2,4-di(3,4-dimethylbenzyl)sorbitol, 0.085 wt% of pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 0.085 wt% of tris(2,4-di-tert-butylphenyl) phosphite by weight percentage.

[0050] Random copolymer polypropylene, styrene-ethylene / butene-styrene block copolymer, 1,3:2,4-di(3,4-dimethylbenzyl)sorbitol, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and tris(2,4-di-tert-butylphenyl) phosphite were added to a high-speed mixer and mixed at 500 rpm for 6 minutes to obtain a mixture.

[0051] The mixture is fed into a co-rotating twin-screw extruder for melt extrusion granulation. The feeding section temperature of the co-rotating twin-screw extruder is set to 165℃, the melting section temperature to 190℃, the homogenization section temperature to 210℃, and the die temperature to 210℃. The screw speed is controlled at 350 rpm. The melt strip extruded from the co-rotating twin-screw extruder is then subjected to water ring pelletizing and drying to obtain a heat-sealing layer masterbatch.

[0052] A three-layer co-extrusion casting process is adopted, using heat-sealing layer masterbatch as the inner layer material, homopolymer polypropylene as the middle support layer material, and polyethylene terephthalate-1,4-cyclohexanediol ester as the outer layer material. The co-extrusion is carried out through a multi-manifold die at a temperature of 225°C, and the casting roller temperature is set to 22°C. After traction and winding, a non-PVC film with a thickness of 200μm is obtained.

[0053] Preparation Example 2:

[0054] This preparation example provides a method for preparing a heat-sealing layer composition and a non-PVC film, including the following steps:

[0055] Weigh out 75.0 wt% of random copolymer polypropylene, 24.65 wt% of styrene-ethylene / butene-styrene block copolymer, 0.15 wt% of 1,3:2,4-di(3,4-dimethylbenzyl)sorbitol, 0.10 wt% of pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 0.10 wt% of tris(2,4-di-tert-butylphenyl) phosphite by weight percentage.

[0056] Random copolymer polypropylene, styrene-ethylene / butene-styrene block copolymer, 1,3:2,4-di(3,4-dimethylbenzyl)sorbitol, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and tris(2,4-di-tert-butylphenyl) phosphite were added to a high-speed mixer and mixed at 400 rpm for 8 minutes to obtain a mixture.

[0057] The mixture is fed into a co-rotating twin-screw extruder for melt extrusion granulation. The feeding section temperature of the co-rotating twin-screw extruder is set to 160℃, the melting section temperature to 185℃, the homogenization section temperature to 205℃, and the die temperature to 210℃. The screw speed is controlled at 300 rpm. The melt strip extruded from the co-rotating twin-screw extruder is then subjected to water ring pelletizing and drying to obtain a heat-sealing layer masterbatch.

[0058] A three-layer co-extrusion casting process is adopted, using heat-sealing layer masterbatch as the inner layer material, homopolymer polypropylene as the middle support layer material, and polyethylene terephthalate-1,4-cyclohexanediol ester as the outer layer material. The co-extrusion is carried out through a multi-manifold die at a temperature of 220°C, with the casting roller temperature set at 20°C. After traction and winding, a non-PVC film with a thickness of 180μm is obtained.

[0059] Preparation Example 3:

[0060] This preparation example provides a method for preparing a heat-sealing layer composition and a non-PVC film, including the following steps:

[0061] Weigh out 68.5 wt% of random copolymer polypropylene, 31.0 wt% of styrene-ethylene / butene-styrene block copolymer, 0.35 wt% of 1,3:2,4-di(3,4-dimethylbenzyl)sorbitol, 0.075 wt% of pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 0.075 wt% of tris(2,4-di-tert-butylphenyl) phosphite by weight percentage.

[0062] Random copolymer polypropylene, styrene-ethylene / butene-styrene block copolymer, 1,3:2,4-di(3,4-dimethylbenzyl)sorbitol, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and tris(2,4-di-tert-butylphenyl) phosphite were added to a high-speed mixer and mixed at 600 rpm for 5 min to obtain a mixture.

[0063] The mixture is fed into a co-rotating twin-screw extruder for melt extrusion granulation. The feeding section temperature of the co-rotating twin-screw extruder is set to 175℃, the melting section temperature to 195℃, the homogenization section temperature to 215℃, and the die temperature to 210℃. The screw speed is controlled at 450 rpm. The melt strip extruded from the co-rotating twin-screw extruder is then subjected to water ring pelletizing and drying to obtain a heat-sealing layer masterbatch.

[0064] A three-layer co-extrusion casting process is adopted, using heat-sealing layer masterbatch as the inner layer material, homopolymer polypropylene as the middle support layer material, and polyethylene terephthalate-1,4-cyclohexanediol ester as the outer layer material. The co-extrusion is carried out through a multi-manifold die at a temperature of 230°C, and the casting roller temperature is set to 25°C. After traction and winding, a non-PVC film with a thickness of 220μm is obtained.

[0065] Examples 1-3:

[0066] Example 1:

[0067] This embodiment provides a bag-making and sealing method using double non-PVC film, including the following steps:

[0068] The constant temperature of the moving mold heat sealing knife in heat sealing station A is set to 160℃, and the constant temperature of the stationary mold heat sealing knife in heat sealing station A is set to 128℃; the surface temperature of the cold pressing block in cooling station B is set to 20℃.

[0069] The non-PVC film prepared by Preparation Example 1 is fed into the forming station by a servo traction roller to form a bag. The filling pump is then started to fill the bag with liquid medicine.

[0070] The bag containing the medicine is transferred to heat sealing station A. The first servo cylinder drives the moving mold heat sealing knife and the stationary mold heat sealing knife of heat sealing station A to close the area of ​​the bag to be sealed. The first servo cylinder applies an initial mechanical pressure of 0.55MPa and maintains it for 0.12s (i.e., the first time period).

[0071] To maintain the closed state of the moving mold heat sealing knife and the stationary mold heat sealing knife at heat sealing station A, the first servo cylinder executes a pressure step command to reduce the mold closing pressure from 0.55MPa to the critical heat transfer pressure of 0.28MPa, and maintains it for 0.45s (i.e. the second time period).

[0072] The moving mold heat sealing knife and the stationary mold heat sealing knife of heat sealing station A are opened, and the servo traction roller transfers the bag to cooling station B at a linear speed of 200 mm / s. During the transfer of the bag and after the bag reaches cooling station B, a longitudinal mechanical tensile tension of 4.0 N is applied to the sealing area of ​​the bag through the damping tension roller.

[0073] The cold pressing block of cooling station B closes and clamps the bag sealing area, and the second servo cylinder instantly applies a holding pressure of 0.75MPa, which is maintained for 0.50s (i.e. the third time period).

[0074] When the cold pressing block of cooling station B is opened, the damping tension roller releases the longitudinal mechanical tensile tension, completing the bag making and sealing process.

[0075] The bag is placed in a pulsating vacuum autoclave to perform the terminal sterilization program, with three pulsating vacuum operations to purge the air from the autoclave. High-temperature pure steam is then introduced into the autoclave to raise the temperature to 121°C within 15 minutes, and the temperature is maintained at this constant temperature for 30 minutes. The chamber pressure is maintained at 0.21 MPa. After the constant temperature sterilization is completed, circulating cooling water is sprayed into the autoclave to lower the temperature until it drops to 40°C.

[0076] Example 2:

[0077] This embodiment provides a bag-making and sealing method using double non-PVC film, including the following steps:

[0078] The constant temperature of the moving mold heat sealing knife in heat sealing station A is set to 165℃, and the constant temperature of the stationary mold heat sealing knife in heat sealing station A is set to 132℃; the surface temperature of the cold pressing block in cooling station B is set to 25℃.

[0079] The non-PVC film prepared in Preparation Example 2 is fed into the forming station by a servo traction roller for forming to obtain a bag body, and the filling pump is started to fill the bag body with medicine.

[0080] The bag containing the medicine is transferred to heat sealing station A. The first servo cylinder drives the moving mold heat sealing knife and the stationary mold heat sealing knife of heat sealing station A to close the area of ​​the bag to be sealed. The first servo cylinder applies an initial mechanical pressure of 0.65MPa and maintains it for 0.15s (i.e., the first time period).

[0081] To maintain the closed state of the moving mold heat sealing knife and the stationary mold heat sealing knife at heat sealing station A, the first servo cylinder executes a pressure step command to suddenly reduce the mold closing pressure from 0.65MPa to the critical heat transfer pressure of 0.32MPa, and maintains it for 0.55s (i.e., the second time period).

[0082] The moving mold heat sealing knife and the stationary mold heat sealing knife of heat sealing station A are opened, and the servo traction roller transfers the bag to cooling station B at a linear speed of 250 mm / s. During the transfer of the bag and after the bag reaches cooling station B, a longitudinal mechanical tensile tension of 5.5 N is applied to the sealing area of ​​the bag through the damping tension roller.

[0083] The cold pressing block of cooling station B closes and clamps the bag sealing area, and the second servo cylinder instantly applies a holding pressure of 0.85MPa, which is maintained for 0.60s (i.e. the third time period).

[0084] When the cold pressing block of cooling station B is opened, the damping tension roller releases the longitudinal mechanical tensile tension, completing the bag making and sealing process.

[0085] The bag is placed in a pulsating vacuum autoclave to perform the terminal sterilization program, with four pulsating vacuum operations to purge the air from the autoclave. High-temperature pure steam is then introduced into the autoclave to raise the temperature to 125°C within 20 minutes, and the temperature is maintained at this constant temperature for 35 minutes. The chamber pressure is maintained at 0.25 MPa. After the constant temperature sterilization is completed, circulating cooling water is sprayed into the autoclave to lower the temperature until it drops to 45°C.

[0086] Example 3:

[0087] This embodiment provides a bag-making and sealing method using double non-PVC film, including the following steps:

[0088] The constant temperature of the moving mold heat sealing knife in heat sealing station A is set to 155℃, and the constant temperature of the stationary mold heat sealing knife in heat sealing station A is set to 125℃; the surface temperature of the cold press block in cooling station B is set to 15℃.

[0089] The non-PVC film prepared by Preparation Example 3 is introduced into the forming station by a servo traction roller for forming to obtain a bag body, and the filling pump is started to fill the bag body with medicine.

[0090] The bag containing the medicine is transferred to heat sealing station A. The first servo cylinder drives the moving mold heat sealing knife and the stationary mold heat sealing knife of heat sealing station A to close the area of ​​the bag to be sealed. The first servo cylinder applies an initial mechanical pressure of 0.50 MPa and maintains it for 0.10 s (i.e., the first time period).

[0091] To maintain the closed state of the moving mold heat sealing knife and the stationary mold heat sealing knife at heat sealing station A, the first servo cylinder executes a pressure step command to suddenly reduce the mold closing pressure from 0.50MPa to the critical heat transfer pressure of 0.22MPa, and maintains it for 0.35s (i.e., the second time period).

[0092] The moving mold heat sealing knife and the stationary mold heat sealing knife of heat sealing station A are opened, and the servo traction roller transfers the bag to cooling station B at a linear speed of 150 mm / s. During the transfer of the bag and after the bag reaches cooling station B, a longitudinal mechanical tensile tension of 3.0 N is applied to the sealing area of ​​the bag through the damping tension roller.

[0093] The cold pressing block of cooling station B closes and clamps the bag sealing area, and the second servo cylinder instantly applies a holding pressure of 0.65MPa, which is maintained for 0.40s (i.e. the third time period).

[0094] When the cold pressing block of cooling station B is opened, the damping tension roller releases the longitudinal mechanical tensile tension, completing the bag making and sealing process.

[0095] The bag is placed in a pulsed vacuum autoclave for terminal sterilization. Two pulsed vacuuming operations are performed to purge the air from the autoclave. High-temperature pure steam is then introduced into the autoclave to raise the temperature to 120°C within 10 minutes. This constant temperature sterilization is maintained for 25 minutes, with the chamber pressure kept at 0.20 MPa. After the constant temperature sterilization is complete, circulating cooling water is sprayed into the autoclave to lower the temperature until it drops to 35°C.

[0096] Comparative Examples 1-7:

[0097] Comparative Example 1:

[0098] Compared with Example 1, the difference is that the constant temperature of the moving mold heat sealing knife in heat sealing station A is set to 160°C, the constant temperature of the stationary mold heat sealing knife in heat sealing station A is set to 160°C, and the servo cylinder continuously applies a mechanical pressure of 0.55MPa throughout the clamping process of heat sealing station A, without executing the pressure step command. All other aspects are the same.

[0099] Comparative Example 2:

[0100] Compared with Example 1, the difference is that the constant temperature of the moving mold heat sealing knife in heat sealing station A is set to 160°C, and the constant temperature of the stationary mold heat sealing knife in heat sealing station A is set to 160°C, while the rest are the same.

[0101] Comparative Example 3:

[0102] Compared with Example 1, the difference is that the servo cylinder continuously applies a mechanical pressure of 0.55MPa throughout the entire heat sealing station A clamping process, and does not execute the pressure step command; all other aspects are the same.

[0103] Comparative Example 4:

[0104] Compared with Example 1, the difference is that the servo cylinder executes a pressure step command to suddenly reduce the mold closing pressure from 0.55MPa to 0.10MPa for 0.45s, while the rest are the same.

[0105] Comparative Example 5:

[0106] Compared with Example 1, the difference is that during the bag transfer process and after the bag reaches the cooling station B, no longitudinal mechanical tensile tension is applied to the bag sealing area through the damping tension roller; all other aspects are the same.

[0107] Comparative Example 6:

[0108] Compared with Example 1, the difference is that in the cooling station B, the cold pressing block closes and clamps the bag sealing area, and the servo cylinder only applies a contact pressure of 0.10MPa for a duration of 0.50s. All other aspects are the same.

[0109] Comparative Example 7:

[0110] Compared with Example 1, the difference is that the non-PVC film prepared by Preparation Example 1 in Example 1 was replaced with a comparative non-PVC film that does not contain 1,3:2,4-di(3,4-dimethylbenzyl)sorbitol, and all other aspects are the same.

[0111] Test Examples 1-4:

[0112] Test Example 1: Determination of Thickness Retention Rate in Sealed Area

[0113] Along the direction perpendicular to the sealing, a strip sample with a size of 15mm×50mm was cut from the bag body prepared in Examples 1 to 3 and Comparative Examples 1 to 7. The strip sample includes the sealing area after the heat sealing station A and the cooling station B, as well as the non-PVC film body area that was not heated or compressed.

[0114] The long strip sample was placed in a standard experimental environment with a temperature of 23℃ and a relative humidity of 50% for conditioning, and the conditioning time was set to 24h.

[0115] A high-precision thickness gauge with an accuracy of 0.001 mm was used to measure the total thickness of the double-layer non-PVC film at 5 equally spaced points in the non-PVC film body area, and the average value was calculated as the initial thickness T0; 5 equally spaced points were also selected on the geometric center line of the sealing area to measure the total thickness after sealing, and the average value was calculated as the heat-sealed thickness T1.

[0116] According to the formula The thickness retention rates of Examples 1 to 3 and Comparative Examples 1 to 7 were calculated respectively.

[0117] Table 1. Test data on thickness retention rate of sealed area

[0118] Example 1 0.401 0.394 98.25 Example 2 0.362 0.350 96.69 Example 3 0.443 0.438 98.87 Comparative Example 1 0.401 0.178 44.39 Comparative Example 2 0.400 0.231 57.75 Comparative Example 3 0.402 0.205 51.00 Comparative Example 4 0.401 0.398 99.25 Comparative Example 5 0.400 0.375 93.75 Comparative Example 6 0.399 0.380 95.24 Comparative Example 7 0.401 0.384 95.76

[0119] Conclusions and Analysis:

[0120] According to Table 1 and Figure 1 The data shows that the thickness retention rates of Examples 1 to 3 all exceeded 96.00%, while the thickness retention rates of Comparative Examples 1, 2, and 3 were only 44.39%, 57.75%, and 51.00%, respectively. Comparative Example 1 used a combination of symmetrical high temperature and constant high pressure, causing the entire inner layer of the non-PVC film to reach a molten state. The apparent viscosity of the polymer decreased exponentially, resulting in irreversible plastic flow under a mechanical pressure of 0.55 MPa, leading to extrusion thinning of the non-PVC film. Comparative Example 2 used a combination of symmetrical high temperature and step pressure reduction. Because both sides of the non-PVC film were in a low-viscosity fluid state, the non-PVC film lost the support of the high-elastic matrix, still resulting in significant casting deformation. Comparative Example 3 used a combination of asymmetrical temperature field and constant high pressure. The 0.55 MPa mechanical pressure exceeded the shear yield stress of the low-viscosity melt layer in the confined space on one side. The excessively high mechanical pressure directly broke through the rigid physical barrier acted by the high-viscosity sub-melting point layer on the stationary mold side, causing macroscopic thinning of the non-PVC film.

[0121] Comparative analysis of data from Examples 1 to 3 and Comparative Examples 1 to 3 demonstrates that an asymmetric temperature field combined with a critical heat transfer pressure successfully constructs a high-viscosity rheological barrier. Under the influence of asymmetric heat flux, a steep temperature gradient forms along the thickness direction of the non-PVC film. Polymer chain segments near the moving mold heat-sealing blade absorb heat, overcome the viscous flow activation energy barrier, and transform into a low-viscosity fluid state. The polymer matrix near the stationary mold heat-sealing blade remains frozen in a high-viscosity, high-elasticity state within the sub-melting point temperature range. The set critical heat transfer pressure precisely eliminates the high interfacial contact thermal resistance caused by the micro-roughness of the polymer surface, ensuring that heat is conducted strictly according to Fourier's heat transfer law to the internal interface of the non-PVC film. Simultaneously, the critical heat transfer pressure is lower than the shear yield stress of the low-viscosity melt layer. The high-viscosity submelting point layer acts as a rigid physical barrier, confining the phase change process within the geometric contact surface of the two non-PVC films. Within the confined space, macromolecular chain segments undergo purely thermodynamic interfacial entanglement, completely blocking the lateral plastic extrusion of the low-viscosity melt into the low-pressure area from the underlying rheological mechanism, thus solving the edge thinning defect.

[0122] Furthermore, although Comparative Example 4 achieved a thickness retention rate of 99.25%, the set micro-positive pressure of 0.10 MPa could not overcome the high interfacial contact thermal resistance, and the overheated heat could not penetrate the interface. The macromolecular chain segments inside the non-PVC film could not reach the activation energy state required for cross-interfacial entanglement. In essence, it was a false thickness retention caused by the interface separation caused by ineffective heat sealing.

[0123] Test Example 2: Evaluation of Macroscopic Warpage Index of Bag Body

[0124] In a standard experimental environment, the bags prepared by Examples 1 to 3 and Comparative Examples 1 to 7 were placed flat on a granite testing platform with an absolutely horizontal surface. The temperature of the standard experimental environment was set to 23°C, the relative humidity of the standard experimental environment was set to 50%, and the static adjustment time of the bags on the granite testing platform was set to 24 hours, so that the residual stress inside the bags could be released naturally.

[0125] A 500g flat pressing block is used to cover the non-PVC film body area of ​​the bag that has not been heat-sealed, ensuring that the non-PVC film body area of ​​the bag that has not been heat-sealed is completely in contact with the surface of the granite testing platform.

[0126] A digital vernier height gauge with an accuracy of 0.01 mm was used, with the surface of the granite testing platform as the horizontal reference plane, and five measurement points were selected at equal intervals along the edge of the bag sealing area.

[0127] Move the probe of the digital display vernier height gauge until it contacts the measurement point, and read the vertical height value of the bag's sealing edge deviating from the horizontal reference plane. Take the maximum vertical height value among the 5 measurement points as the macroscopic warpage index of the bag.

[0128] Table 2. Test data of macroscopic warpage index of bag body

[0129] Example 1 0.08 0.12 0.17 0.14 0.11 0.17 Example 2 0.03 0.05 0.08 0.07 0.04 0.08 Example 3 0.15 0.21 0.24 0.18 0.16 0.24 Comparative Example 1 0.32 0.38 0.41 0.35 0.29 0.41 Comparative Example 2 0.44 0.52 0.55 0.47 0.41 0.55 Comparative Example 3 2.85 3.34 3.82 3.61 3.12 3.82 Comparative Example 4 0.88 1.05 1.16 0.94 0.85 1.16 Comparative Example 5 4.65 5.02 5.23 4.88 4.71 5.23 Comparative Example 6 2.14 2.45 2.67 2.51 2.22 2.67 Comparative Example 7 2.55 2.88 3.12 2.95 2.74 3.12

[0130] Conclusions and Analysis:

[0131] According to Table 2 and Figure 2 The data from Examples 1 to 3 show that the macroscopic warpage index is controlled below 0.25 mm, exhibiting good flatness, while the macroscopic warpage index of Comparative Example 5 is as high as 5.23 mm, indicating macroscopic curling deformation. The significant data difference between Examples 1 to 3 and Comparative Example 5 directly verifies the nonlinear synergistic effect between the micro-tension damping displacement step and the asymmetric temperature field step. In heat sealing station A, due to the significant temperature difference between the moving mold heat sealing knife and the stationary mold heat sealing knife, the two sides of the non-PVC film experience extremely unbalanced volume expansion and contraction during heating and subsequent cooling. This thermodynamic asymmetry induces interlaminar shear residual stress in the thickness direction of the non-PVC film, similar to the bimetallic strip effect. Comparative Example 5 does not apply longitudinal mechanical tensile tension to the bag sealing area through the damping tension roller during bag transfer, causing the polymer chain segments of the composition inside the non-PVC film to be completely controlled by asymmetric thermal shrinkage stress during cooling and solidification, ultimately manifesting as a severe deviation of the bag sealing edge from the horizontal reference plane in macroscopic morphology.

[0132] In Examples 1 to 3, longitudinal mechanical tensile tension was applied by a damping tension roller during the window period when the polymer was in a semi-molten state. This longitudinal mechanical tensile tension, acting as an external mechanical field, forced the random copolymer polypropylene backbone segments and the elastic segments in the styrene-ethylene / butene-styrene block copolymer of the heat-sealing layer composition to undergo conformational rearrangement and high orientation along the direction of force. The highly oriented polymer segments were instantly frozen by the cold pressing block at cooling station B, storing uniform elastic strain energy within the non-PVC film. This stored elastic strain energy perfectly offset the residual stress of asymmetric thermal shrinkage caused by asymmetric heat flux in the mechanical vector direction. Through the underlying energy balance of thermodynamics and macroscopic mechanics, the kinetic source of macroscopic warping in the non-PVC film was eliminated, ensuring that the bag sealing area remained absolutely flat.

[0133] Test Example 3: Analysis of Mechanical Properties and Fracture Modes of T-Type Peeling at Sealing Interface

[0134] Along the direction perpendicular to the bag sealing, a strip sample with a width of 15 mm was cut from the bag prepared in Examples 1 to 3 and Comparative Examples 1 to 7. The strip sample included the complete sealing area after the heat sealing station A and the cooling station B, as well as the non-PVC film body area that was not heated or compressed.

[0135] The long strip sample was placed in a standard experimental environment with a temperature of 23℃ and a relative humidity of 50% for conditioning, and the conditioning time was set to 24h.

[0136] The T-shaped peel test was performed using an electronic universal testing machine. The two ends of the non-PVC film body area of ​​the long strip sample that was not heat-sealed were clamped in the upper and lower clamps of the electronic universal testing machine, respectively, so that the non-PVC film body area of ​​the long strip sample that was not heat-sealed and the sealing area formed a T-shaped structure.

[0137] The tensile speed of the electronic universal testing machine was set to 300 mm / min. The machine was started to stretch the long strip specimen. The machine recorded the change in peel force value in real time during the stretching process and extracted the maximum peel force value as the T-shaped peel force.

[0138] After the tensile test, observe the final fracture location and morphology of the long strip specimen, and record the fracture mode as yielding and tensile fracture of the parent material, fracture at the root of the sealing edge, or false sealing of the interface.

[0139] Table 3. Test data of mechanical properties and fracture modes of T-type peel at the sealing interface.

[0140] Example 1 42.15 41.87 43.52 42.51 Base material yielding and tensile fracture Example 2 45.62 43.91 44.88 44.80 Base material yielding and tensile fracture Example 3 39.85 41.12 40.06 40.34 Base material yielding and tensile fracture Comparative Example 1 24.33 25.18 23.79 24.43 The seal edge broke at the root. Comparative Example 2 27.85 26.91 28.34 27.70 The seal edge broke at the root. Comparative Example 3 21.46 23.05 22.18 22.23 The seal edge broke at the root. Comparative Example 4 11.45 13.22 10.89 11.85 Interface separation fake seal Comparative Example 5 31.55 30.82 32.14 31.50 The seal edge broke at the root. Comparative Example 6 26.73 25.41 27.09 26.41 Interface separation fake seal Comparative Example 7 29.81 28.56 30.12 29.50 The seal edge broke at the root.

[0141] Conclusions and Analysis:

[0142] According to Table 3 and Figure 3 The data shows that the average T-peel force of Examples 1 to 3 all exceeded 40.00 N / 15 mm, and the fracture mode of all examples was yielding and breaking of the parent material, proving that the tensile crack strength of the sealing interface prepared in Examples 1 to 3 exceeded the tensile yield strength of the non-PVC film body. The average T-peel force of Comparative Example 4 was only 11.85 N / 15 mm, and the fracture mode was interface separation and false sealing. When Comparative Example 4 executed the pressure step command at heat sealing station A, the mold closing pressure was suddenly reduced to 0.10 MPa. The micro-positive pressure of 0.10 MPa could not overcome the high interfacial contact thermal resistance caused by the micro-roughness of the two non-PVC film surfaces. The heat provided by the moving mold heat sealing knife could not effectively penetrate the interface, resulting in the polymer chain segments of the internal interface of the non-PVC film not absorbing enough energy to reach the viscous flow activation state. Due to the lack of sufficient thermodynamic energy, the macromolecular chain segments could not entangle with each other across the interface, ultimately resulting in the sealing interface failing to form an effective bond. Examples 1 to 3, by setting a critical heat transfer pressure, both avoided melt extrusion and ensured the elimination of contact thermal resistance, thus achieving deep diffusion and entanglement of polymer chain segments.

[0143] The average T-peel force of Comparative Example 6 was 26.41 N / 15 mm, and the fracture mode was interface separation pseudo-sealing; the average T-peel force of Comparative Example 7 was 29.50 N / 15 mm, and the fracture mode was fracture at the root of the sealing edge. Comparative Example 6 applied only 0.10 MPa of contact pressure at cooling station B, lacking the high-pressure conditions to counteract the free volume shrinkage of the non-PVC film during phase change cooling. Under static cooling conditions, isotropic spherulitic structures spontaneously formed inside the non-PVC film, preventing the formation of a spherulitic microstructure growing along the tensile stress direction. The heat-sealing composition of Comparative Example 7 lacked 1,3:2,4-di(3,4-dimethylbenzylene)sorbitol; due to the absence of heterogeneous nucleation sites, even with longitudinal mechanical tensile tension and holding pressure, the crystallization kinetic path could not be effectively shifted. Examples 1 to 3, through the instantaneous application of high-pressure holding pressure and the nucleation sites provided by 1,3:2,4-bis(3,4-dimethylbenzylene)sorbitol, forced the macromolecular chain segments to form a tandem crystal structure under the induction of mechano-thermal coupling crystallization kinetics. The tandem crystal structure endows the non-PVC film sealing interface with high tensile crack resistance and peel dissipation resistance along the stress direction, ensuring that when the non-PVC film is subjected to ultimate load, the stress can be uniformly transmitted to the non-PVC film body through the crystal network, thereby achieving the ideal fracture mode of yielding and tensile fracture of the parent material.

[0144] The fracture mode of Comparative Examples 1 to 3 and Comparative Example 5 was fracture at the root of the sealing edge. Combined with the data from Test Examples 1 and 2, it can be seen that excessive melt extrusion and macroscopic warping introduce severe geometric abrupt changes and residual stress concentration points in the sealing edge region of the non-PVC film. During the T-peel test, the applied load rapidly induced microcracks at the geometric abrupt changes and residual stress concentration points, leading to crack propagation and causing the non-PVC film to fracture at the root of the sealing edge under stress conditions far below its intrinsic strength. Examples 1 to 3, by eliminating edge thinning and macroscopic warping, eliminated stress concentration defects and ensured the integrity of the macroscopic mechanical properties of the non-PVC film sealing region.

[0145] Test Example 4: Terminal Pulsating Vacuum High-Temperature Sterilization Bag Breakage Rate Test

[0146] Eighty-one bags each prepared by Examples 1 to 3 and Comparative Examples 1 to 7 were selected and placed evenly on the sterilization rack of the pulsed vacuum autoclave.

[0147] Close the sealed door of the pulsed vacuum autoclave and start the standard terminal sterilization program. The pulsed vacuum autoclave first performs three pulsed vacuuming operations to purge the air from the autoclave.

[0148] High-temperature pure steam is introduced into the pulsating vacuum autoclave, causing the temperature inside the pulsating vacuum autoclave to gradually rise to 121°C within 15 minutes, and the constant temperature sterilization state of 121°C is maintained for 30 minutes. The chamber pressure inside the pulsating vacuum autoclave is maintained at 0.21 MPa.

[0149] After the constant temperature sterilization is completed, spray circulating cooling water into the pulsed vacuum autoclave for cooling until the temperature inside the pulsed vacuum autoclave drops below 40°C. Then, open the sealed door and remove the bag.

[0150] Each bag removed was inspected manually to determine its appearance. The number of bags with macroscopic physical rupture or leakage of medicine in the sealed area was counted. The macroscopic bag breakage rate of each group was calculated according to the formula: bag breakage rate = (number of broken bags / total number of tests) × 100%.

[0151] Table 4. Test data on bag breakage rate of terminal pulsed vacuum high-temperature sterilization

[0152] Example 1 800 0 0.00 Example 2 800 0 0.00 Example 3 800 1 0.12 Comparative Example 1 800 142 17.75 Comparative Example 2 800 116 14.50 Comparative Example 3 800 131 16.37 Comparative Example 4 800 385 48.12 Comparative Example 5 800 89 11.12 Comparative Example 6 800 214 26.75 Comparative Example 7 800 187 23.37

[0153] Conclusions and Analysis:

[0154] According to Table 4 and Figure 4The data shows that the bag breakage rate in Examples 1 and 2 was 0.00%, while the breakage rate in Example 3 was only 0.12%, proving that the bags prepared in Examples 1 to 3 can fully withstand the extreme high-temperature and high-pressure sterilization environment. Conversely, Comparative Examples 1 to 7 exhibited higher breakage rates under the same terminal pulsating vacuum high-temperature sterilization process, ranging from 11.12% to 48.12%. The pulsating vacuum high-temperature sterilization process represents the most demanding thermodynamic and mechanical stress environment in the bag-making and sealing process. The alternating positive and negative pressure caused by pulsating vacuum, the high-temperature steam heating at 121°C, and the instantaneous impact of cooling water create a severe environmental stress coupling effect on the sealing area of ​​the non-PVC film.

[0155] Analysis of thickness data and fracture modes reveals that Comparative Examples 1 to 3, due to the lack of an asymmetric temperature field or the failure to execute the critical heat transfer pressure reduction command, experienced significant extrusion and casting of the non-PVC film, resulting in macroscopic thickness reduction points at the sealing edges. These thickness reduction points became critical stress concentration areas in the pulsating vacuum autoclave. At a high temperature of 121℃, the mechanical strength of the polymer matrix decreased significantly, and the pressure difference between the pulsating vacuum stage and the cooling water spray stage directly tore apart the thickness reduction points, causing leakage of the medicine. In Comparative Example 4, the micro-positive pressure failed to overcome the high interfacial contact thermal resistance, and the molecular chains failed to achieve cross-interfacial entanglement, resulting in a false seal state of interfacial separation. At room temperature, the false seal interface could still maintain a certain degree of adhesion, but in the high-temperature and high-pressure steam environment of 121℃, the high temperature accelerated the penetration of water molecules into the interface, and the thermal expansion effect caused the two layers of non-PVC film that had not undergone true molecular chain physical entanglement to peel off, resulting in a bag breakage rate as high as 48.12%.

[0156] Comparative Example 5 lacked longitudinal mechanical tensile tension, and the unbalanced thermal shrinkage caused by the asymmetric temperature field resulted in a large amount of interlaminar shear residual stress being sealed inside the non-PVC film. Under the high temperature of 121°C, the thermal mobility of the polymer chain segments increased, and the frozen residual stress was violently re-released. The residual stress superimposed with the internal pressure generated by the thermal expansion of the internal liquid, resulting in thermal stress tearing at the edge of the bag seal. Comparative Examples 6 and 7 lacked cooling and holding pressure and nucleating agents, respectively, causing isotropic spherulitic structures to spontaneously form inside the non-PVC film during the phase change curing stage. The spherulitic structure partially softened or relaxed at the high temperature of 121°C, causing the sealing interface to lose its mechanical dissipation ability along the direction of force. When the liquid inside the bag generated huge expansion tension at high temperature, the spherulitic network could not effectively transfer and disperse the stress, ultimately causing the sealing interface to burst from the inside due to the tension of the liquid.

[0157] Examples 1 to 3 constructed a high-viscosity rheological barrier by combining an asymmetric temperature field with critical heat transfer pressure, avoiding stress concentration caused by extrusion thinning; applied a mechanical field with damping tension to force chain segment orientation, eliminating residual stress caused by asymmetric thermal shrinkage; and induced a highly oriented crystalline structure under mechanical-thermal coupling through instantaneous high-pressure holding combined with a nucleating agent. These features exhibit a deep nonlinear synergistic effect, ensuring that the non-PVC film sealing area maintains high thermodynamic stability and structural integrity even under extreme thermal shock at 121°C and drastic pressure fluctuations, meeting the engineering standards required for industrial production of pharmaceutical packaging.

Claims

1. A method for filling and sealing bags made of double non-PVC film, characterized in that, Includes the following steps: A non-PVC film is introduced into the forming station for forming to obtain a bag body, and the filling pump is started to fill the bag body with liquid medicine. The bag body, after completing the filling operation, is transferred to the heat sealing station A. The moving mold heat sealing knife and the stationary mold heat sealing knife of the heat sealing station A are driven to close and clamp the area of ​​the bag body to be sealed, and initial mechanical pressure is applied and maintained for a first time period. Maintain the closed state of the moving mold heat sealing knife and the stationary mold heat sealing knife, execute the pressure step command, reduce the mold closing pressure from the initial mechanical pressure to the critical heat transfer pressure, and maintain it for the second time period; The moving mold heat sealing knife and the stationary mold heat sealing knife are opened to transfer the bag body to the cooling station B. During the transfer of the bag body and after the bag body arrives at the cooling station B, longitudinal mechanical tensile tension is applied to the sealing area of ​​the bag body by the damping tension roller. The cold pressing block of the cooling station B closes and clamps the sealing area of ​​the bag, applies pressure, and maintains it for the third time period. When the cold pressing block is opened, the damping tension roller releases the longitudinal mechanical tensile tension, completing the bag making and sealing process.

2. The bag-making and sealing method using double non-PVC film according to claim 1, characterized in that, The constant temperature of the moving mold heat sealing knife is set to 155℃~165℃; The constant temperature of the static mold heat sealing knife is set to 125℃~132℃; The surface temperature of the cold-pressed block is set to 15℃~25℃.

3. The bag-making and sealing method using double non-PVC film according to claim 1, characterized in that, The initial mechanical pressure is 0.50 MPa to 0.65 MPa, and the first time period is 0.10 s to 0.15 s; The critical heat transfer pressure is 0.22 MPa to 0.32 MPa, and the second time period is 0.35 s to 0.55 s; The pressure holding pressure is 0.65MPa to 0.85MPa, and the third time period is 0.40s to 0.60s.

4. The bag-making and sealing method using double non-PVC film according to claim 1, characterized in that, The linear velocity at which the bag is transferred to the cooling station B is 150 mm / s to 250 mm / s, and the longitudinal mechanical tensile tension is 3.0 N to 5.5 N.

5. The bag-making and sealing method using double non-PVC film according to claim 1, characterized in that, The non-PVC film comprises an inner layer, a middle support layer, and an outer layer; The inner layer is made of heat-sealing masterbatch, the middle support layer is made of homopolymer polypropylene, and the outer layer is made of poly(1,4-cyclohexanediol) terephthalate.

6. The bag-making and sealing method using double non-PVC film according to claim 5, characterized in that, The heat-sealing masterbatch comprises the following raw materials in weight percentages: 68.5wt%–75.0wt% random copolymer polypropylene, 24.65wt%–31.0wt% styrene-ethylene / butene-styrene block copolymer, 0.15wt%–0.35wt% 1,3:2,4-di(3,4-dimethylbenzyl)sorbitol, 0.075wt%–0.10wt% pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and 0.075wt%–0.10wt% tris(2,4-di-tert-butylphenyl) phosphite.

7. The bag-making and sealing method using double non-PVC film according to claim 6, characterized in that, The preparation steps of the heat-sealing layer masterbatch include: The random copolymer polypropylene, the styrene-ethylene / butene-styrene block copolymer, the 1,3:2,4-di(3,4-dimethylbenzyl)sorbitol, the pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the tris(2,4-di-tert-butylphenyl) phosphite were added to a high-speed mixer and mixed at 400-600 rpm for 5-8 minutes to obtain a mixture. The mixture is fed into a co-rotating twin-screw extruder for melt extrusion granulation. The temperature of the feeding section of the co-rotating twin-screw extruder is set to 160℃~175℃, the temperature of the melting section is set to 185℃~195℃, the temperature of the homogenization section is set to 205℃~215℃, and the screw speed is controlled at 300rpm~450rpm. After water ring pelletizing and drying, a heat-sealing layer masterbatch is obtained.

8. The bag-making and sealing method using double non-PVC film according to claim 7, characterized in that, The non-PVC film is produced using a three-layer co-extrusion casting process. The heat-sealing layer masterbatch, the homopolymer polypropylene, and the poly(1,4-cyclohexanedimethyl terephthalate) are co-extruded through a multi-manifold die at a temperature of 220°C to 230°C. The casting roller temperature is set to 20°C to 25°C to obtain a non-PVC film with a thickness of 180μm to 220μm.

9. The bag-making and sealing method using double non-PVC film according to claim 1, characterized in that, After the bag is made and sealed, the process further includes placing the bag in a pulsed vacuum autoclave to perform a terminal sterilization procedure, which includes: Perform 2 to 4 pulsed vacuuming operations to purge the air from the pulsed vacuum autoclave. High-temperature pure steam is introduced into the pulsating vacuum autoclave to raise the temperature inside the pulsating vacuum autoclave to 120℃~125℃ within 10min~20min, and maintain the constant temperature sterilization state for 25min~35min. The chamber pressure inside the pulsating vacuum autoclave is maintained at 0.20MPa~0.25MPa. After the constant temperature sterilization process is completed, circulating cooling water is sprayed into the pulsed vacuum high-pressure sterilizer for cooling until the temperature inside the pulsed vacuum high-pressure sterilizer drops to 35℃~45℃.

10. An integrated equipment for bag making and sealing of double non-PVC films, characterized in that, A bag-making and sealing method for performing the double non-PVC film as described in any one of claims 1 to 9 includes a forming station for receiving the imported non-PVC film and performing a forming process to obtain a bag body. A filling pump for filling the bag with liquid medicine; Heat sealing station A includes a moving mold heat sealing knife, a stationary mold heat sealing knife, and a first servo cylinder. The first servo cylinder is used to drive the moving mold heat sealing knife and the stationary mold heat sealing knife to close and execute a pressure step command. A damping tension roller, which is used to apply longitudinal mechanical tensile tension to the sealing area of ​​the bag body; Cooling station B includes a cold pressing block and a second servo cylinder, the second servo cylinder being used to drive the cold pressing block to clamp and apply holding pressure; A servo traction roller is used to pull the bag body to the cooling station B.

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