Preparation method of upright polypropylene infusion bag

Abstract

This invention discloses a method for preparing an upright polypropylene infusion bag, comprising: (1) heating the barrel temperature of a one-step hollow molding machine to 160℃-250℃, injecting molten polypropylene (PP) material into a preform mold under high pressure, and obtaining a preform through pre-blowing treatment; (2) transferring the preform directly into a blow molding machine of an integrated machine without cooling, blow molding while hot, and then cooling to obtain the final product. This invention adopts a hot blowing process. After the preform is temperature-adjusted, it can be directly hot blown into a bottle, which can reduce the number of insoluble particles, improve the stability of the product, eliminate the preform storage and transfer process, and reduce the risk of introducing foreign matter from the source. The product prepared by the hot blowing process has a low shrinkage rate, high bag elasticity, and significantly improved performance such as impact resistance and air permeability, reducing the probability of leakage and increasing the yield. The residual heat during preform molding is used for blow molding, eliminating the need for reheating, which can shorten the molding cycle and reduce energy consumption.

Description

Technical Field

[0001] This invention relates to a method for preparing infusion bags, and more particularly to a method for preparing upright polypropylene infusion bags, belonging to the field of infusion bag preparation. Background Technology

[0002] Large-volume parenteral solutions (LVP), commonly known as large-volume parenteral solutions, typically refer to sterile liquid preparations with a volume of 50 ml or more that are directly administered intravenously. Since their clinical application, the packaging containers for infusion products have undergone three generations of changes. The main packaging materials available in the infusion market are glass bottles, plastic bottles, non-PVC soft bags, and upright soft bags. In the clinical application of large-volume parenteral solutions, a fully closed infusion method can effectively reduce the chance of cross-infection in hospitals, while ensuring the safety and effectiveness of the medication throughout the entire infusion process. Upright polypropylene infusion bags, based on the original polypropylene infusion method, add a self-draining function. Infusions do not require air tubing and can be administered directly using atmospheric pressure, effectively reducing secondary contamination during the infusion process and solving the inherent safety hazards of traditional glass and plastic bottles. Compared to soft bags, they can be placed upright during clinical preparation, making operation convenient and improving the work efficiency of medical staff. Upright polypropylene infusion bag packaging technology is safe and effective, meeting pharmaceutical and environmental requirements, and represents a major development direction for large-volume parenteral solution packaging technology.

[0003] In today's medically advanced society, intravenous infusion has become dominant, with many medications requiring intravenous administration. The advantages are obvious: the infusion rate can be adjusted according to the patient's condition, the dosage is easier to control, and the response is faster. Infusion bags have become indispensable. Current manufacturing processes for upright polypropylene infusion bags employ a two-step process. First, polypropylene (PP) material is made into a preform. After cooling to room temperature for at least 12 hours, the preform is transferred to a blow molding machine, reheated to a molten state, and blown into a bag. After cooling, the lifting ring is welded to the bottom of the bag using specialized welding equipment, creating an upright polypropylene infusion bag. Because the preform needs cooling, storage, and transfer for use, it requires a large storage space. Foreign matter is easily introduced during transfer, causing contamination. Shrinkage during injection molding or leakage during cooling also leads to a high scrap rate, necessitating improvement. Summary of the Invention

[0004] The main objective of this invention is to provide a one-step method for preparing upright polypropylene infusion bags, thereby overcoming the defects of existing two-step preparation processes.

[0005] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0006] A method for preparing an upright polypropylene infusion bag, comprising:

[0007] (1) Pre-forming the preform: Install the preform mold on the one-step hollow molding machine, heat the barrel temperature of the one-step hollow molding machine to 160℃-250℃, add polypropylene (PP) material into the barrel of the one-step hollow molding machine, and inject the polypropylene (PP) material into the preform mold under high pressure after it enters the molten state. The preform is then prepared by pre-blowing with a blow molding machine. During the pre-blowing process, the main runner temperature and the barrel temperature are controlled between 160℃-250℃, the pre-blowing temperature is controlled between 30℃-180℃, and the blow molding temperature controller temperature is controlled between 20℃-100℃.

[0008] (2) The bag preform prepared in step (1) is directly transferred into the blow molding machine of the integrated machine without cooling and blow molded while hot, and then cooled to obtain an upright polypropylene infusion bag.

[0009] This invention involves directly transferring the preform into a blow molding machine while it is still hot, without cooling, and then cooling it. This invention employs optimized hot blowing parameters (such as barrel temperature, pre-blowing temperature, and blow molding temperature controller temperature) to ensure that the preform can be blown to shape after further heating, and it solves the technical problems of light transmittance and automatic liquid drainage in the formed upright polypropylene infusion bag. To explore and select the most suitable temperature parameters, this invention optimizes and selects the barrel temperature, pre-blowing temperature, and blow molding temperature controller temperature.

[0010] In a preferred embodiment of the present invention, in step (1), the barrel temperature of the one-step hollow molding machine is heated to 180°C-230°C, more preferably, the barrel temperature is heated to 220°C-230°C, and most preferably, the barrel temperature is heated to 230°C.

[0011] In a preferred embodiment of the present invention, the pre-blowing temperature is controlled between 100°C and 160°C in step (1), more preferably between 140°C and 160°C, and most preferably at 160°C.

[0012] In a preferred embodiment of the present invention, the temperature of the blow molding temperature controller is controlled between 50°C and 70°C in step (1), more preferably between 60°C and 70°C, and most preferably 70°C.

[0013] This invention reveals that when the barrel temperature is controlled at 230°C, the pre-blowing temperature at 160°C, and the blow molding temperature controller temperature at 70°C, the self-draining time of the prepared upright polypropylene infusion bag decreases to 16 minutes, and the light transmittance reaches 65%, which is significantly better than that of upright polypropylene infusion bags prepared using other temperature parameters.

[0014] The mold-closing operation of the molten plastic barrel is divided into five stages: mold closing stage 1, mold closing stage 2, mold closing stage 3, mold closing low pressure, and mold closing high pressure. When the mold-closing operation of the molten plastic barrel is performed, the mold opening is divided into five stages: mold opening slow speed, mold opening stage 2, mold opening stage 3, mold opening stage 4, and mold opening stage 5. The mold-closing high pressure is set within the range of 5-22MPa, and the mold-closing low pressure is set within the range of 1-10MPa.

[0015] When injecting molten polypropylene (PP) material into the preform mold under high pressure, the injection pressure of the first stage is set to be in the range of 30-200 bar, the injection pressure of the second stage is set to be in the range of 20-130 bar, the injection speed is set to be 10%-99% of the maximum speed, and the injection time is set to be in the range of 2-10 seconds.

[0016] In addition, the present invention can also include a built-in lifting ring during the bag forming process. The preparation of the built-in lifting ring includes: designing a lifting ring structure at the bottom of the bag preform mold, and injection molding the lifting ring and the bag preform together. The equipment used is a one-step hollow molding machine.

[0017] This invention relates to a hot-blowing process for preparing upright polypropylene infusion bags. After temperature adjustment, the preform is directly hot-blown into a bottle, reducing the number of insoluble particles, improving product stability, and eliminating the need for preform storage and transfer, thus reducing the risk of introducing foreign matter at the source. The upright polypropylene infusion bags prepared using this hot-blowing process have lower shrinkage, higher elasticity, and significantly improved impact resistance and air permeability, reducing the probability of leakage and increasing the yield. Utilizing the residual heat from preform molding for (stretch) blow molding eliminates the need for reheating, shortening the molding cycle and reducing energy consumption. This invention effectively solves the problems of existing infusion bag manufacturing processes, which require preform cooling, storage, and transfer for use, necessitating large storage spaces, and the easy introduction of foreign matter during transfer, leading to product contamination, low yield, and high scrap rates due to shrinkage during injection molding or leakage during cooling. Attached Figure Description

[0018] Figure 1 Schematic diagram of the mold locking / unlocking stage. Detailed Implementation

[0019] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as a result. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions to the details and form of the present invention can be made without departing from the spirit and scope of the invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0020] Example 1: Screening Test of Heat Blowing Parameters for Upright Polypropylene Infusion Bags

[0021] I. Experimental Methods

[0022] The optimal parameter range is selected based on a comprehensive evaluation of the bag's appearance, self-discharge time (≤20 min), and light transmittance (≥50%). The three key temperature parameters complement each other and must all meet the temperature requirements to produce qualified and stable products.

[0023] II. Test Results

[0024] The experimental results are shown in Table 1.

[0025] Table 1. Test data of heat blowing parameters for 100ml bags

[0026]

[0027] According to the test results in Table 1, the preferred barrel temperature is 180-230℃, more preferably 220-230℃, and most preferably 230℃; the preferred pre-blowing temperature is 100-160℃, more preferably 140-160℃, and most preferably 160℃; the preferred blow molding temperature controller temperature is 50-70℃, more preferably 60-70℃, and most preferably 70℃. Among these, when the barrel temperature is 230℃, the pre-blowing temperature is 160℃, and the blow molding temperature controller temperature is 70℃, the self-expansion time is 16 minutes, and the light transmittance reaches 65%, which is significantly better than other parameters.

[0028] Example 1: Preparation of Upright Polypropylene Infusion Bag

[0029] (1) Preparation of the preform: In a one-step hollow molding machine (model: GZ-D750-FSIII)

[0030] Purchase Channel: Shunde Gongzheng Packaging Equipment Manufacturing Co., Ltd. Install the preform mold on the machine, heat the barrel temperature of the one-step hollow molding machine to 230℃, add polypropylene (PP) material into the barrel of the one-step hollow molding machine, and after the PP material enters the molten state, inject it into the preform mold under high pressure. The preform is then pre-blown using a blow molding machine to obtain the bag preform. During the pre-blowing process, the main runner temperature is controlled at 230℃, the pre-blowing temperature is controlled at 160℃, and the blow molding temperature controller temperature is controlled at 70℃.

[0031] The mold-closing operation of the molten plastic barrel is divided into five stages: mold closing stage 1, mold closing stage 2, mold closing stage 3, mold closing low pressure, and mold closing high pressure. The mold opening operation of the molten plastic barrel is divided into five stages: mold opening slow speed, mold opening stage 2, mold opening stage 3, mold opening stage 4, and mold opening stage 5. The high pressure of mold closing is set within the range of 5-22MPa, and the low pressure of mold closing is set within the range of 1-10MPa.

[0032] When injecting molten polypropylene (PP) material into the preform mold under high pressure, the pressure of the first injection stage is set to be in the range of 30-200 bar, the pressure of the second injection stage is set to be in the range of 20-130 bar, the injection speed is set to be 10%-99% of the maximum speed, and the injection time is set to be in the range of 2-10 seconds.

[0033] (2) The bag preform prepared in step (1) is directly transferred into a one-step hollow molding machine (model: GZ-D750-FSIII, purchased from Shunde Gongzheng Packaging Equipment Manufacturing Co., Ltd.) without cooling and blow-molded while hot, and then cooled to obtain an upright polypropylene infusion bag.

[0034] After testing, the upright polypropylene infusion bag prepared in this embodiment was found to be of acceptable appearance, with a self-draining time of 16 minutes and a light transmittance of 65%.

[0035] Example 2: Preparation of upright polypropylene infusion bags

[0036] (1) Pre-forming the preform: Install the preform mold on the one-step hollow molding machine, heat the barrel temperature of the one-step hollow molding machine to 220°C, add polypropylene (PP) material into the barrel of the one-step hollow molding machine, and inject the polypropylene (PP) material into the preform mold under high pressure after it enters the molten state. The preform is then prepared by pre-blowing with a blow molding machine. During the pre-blowing process, the main runner temperature is controlled at 220°C, the pre-blowing temperature is controlled at 150°C, and the blow molding temperature controller temperature is controlled at 70°C.

[0037] The mold-closing operation of the molten plastic barrel is divided into five stages: mold closing stage 1, mold closing stage 2, mold closing stage 3, mold closing low pressure, and mold closing high pressure. The mold opening operation of the molten plastic barrel is divided into five stages: mold opening slow speed, mold opening stage 2, mold opening stage 3, mold opening stage 4, and mold opening stage 5. The high pressure of mold closing is set within the range of 5-22MPa, and the low pressure of mold closing is set within the range of 1-10MPa.

[0038] When injecting molten polypropylene (PP) material into the preform mold under high pressure, the pressure of the first injection stage is set to be in the range of 30-200 bar, the pressure of the second injection stage is set to be in the range of 20-130 bar, the injection speed is set to be 10%-99% of the maximum speed, and the injection time is set to be in the range of 2-10 seconds.

[0039] (2) The bag preform prepared in step (1) is directly transferred into the blow molding machine of the integrated machine without cooling and blow molded while hot, and then cooled to obtain an upright polypropylene infusion bag.

[0040] The bag has a built-in lifting ring during the bag forming process. The preparation method includes: designing a lifting ring structure at the bottom of the bag preform mold, and injection molding the lifting ring and the bag preform as a whole. The equipment used is a one-step hollow molding machine, and no additional equipment is required.

[0041] After testing, the upright polypropylene infusion bag prepared in this embodiment was found to be of acceptable appearance, with a self-draining time of 19 minutes and a light transmittance of 60%.

[0042] Example 3: Preparation of Upright Polypropylene Infusion Bag

[0043] (1) Pre-bag preparation: Install a pre-bag mold on a one-step hollow molding machine, heat the barrel temperature of the one-step hollow molding machine to 220°C, add polypropylene (PP) material into the barrel of the one-step hollow molding machine, and inject the polypropylene (PP) material into the pre-bag mold under high pressure after it enters the molten state. The pre-bag is prepared by pre-blowing with a blow molding machine. During the pre-blowing process, the main runner temperature is controlled at 220°C, the pre-blowing temperature is controlled at 140°C, and the blow molding temperature controller temperature is controlled at 60°C.

[0044] The mold-closing operation of the molten plastic barrel is divided into five stages: mold closing stage 1, mold closing stage 2, mold closing stage 3, mold closing low pressure, and mold closing high pressure. The mold opening operation of the molten plastic barrel is divided into five stages: mold opening slow speed, mold opening stage 2, mold opening stage 3, mold opening stage 4, and mold opening stage 5. The high pressure of mold closing is set within the range of 5-22MPa, and the low pressure of mold closing is set within the range of 1-10MPa.

[0045] When injecting molten polypropylene (PP) material into the preform mold under high pressure, the pressure of the first injection stage is set to be in the range of 30-200 bar, the pressure of the second injection stage is set to be in the range of 20-130 bar, the injection speed is set to be 10%-99% of the maximum speed, and the injection time is set to be in the range of 2-10 seconds.

[0046] (2) The bag preform prepared in step (1) is directly transferred into the blow molding machine of the integrated machine without cooling and blow molded while hot, and then cooled to obtain an upright polypropylene infusion bag.

[0047] After testing, the upright polypropylene infusion bag prepared in this embodiment was found to be of acceptable appearance, with a self-draining time of 19 minutes and a light transmittance of 55%.

[0048] Example 4: Preparation of upright polypropylene infusion bags

[0049] (1) Pre-forming the preform: Install the preform mold on the one-step hollow molding machine, heat the barrel temperature of the one-step hollow molding machine to 200°C, add polypropylene (PP) material into the barrel of the one-step hollow molding machine, and inject the polypropylene (PP) material into the preform mold under high pressure after it enters the molten state. The preform is then pre-blown by a blow molding machine to obtain the preform. During the pre-blowing process, the main runner temperature is controlled at 200°C, the pre-blowing temperature is controlled at 120°C, and the blow molding temperature controller temperature is controlled at 60°C.

[0050] The mold-closing operation of the molten plastic barrel is divided into five stages: mold closing stage 1, mold closing stage 2, mold closing stage 3, mold closing low pressure, and mold closing high pressure. The mold opening operation of the molten plastic barrel is divided into five stages: mold opening slow speed, mold opening stage 2, mold opening stage 3, mold opening stage 4, and mold opening stage 5. The high pressure of mold closing is set within the range of 5-22MPa, and the low pressure of mold closing is set within the range of 1-10MPa.

[0051] When injecting molten polypropylene (PP) material into the preform mold under high pressure, the pressure of the first injection stage is set to be in the range of 30-200 bar, the pressure of the second injection stage is set to be in the range of 20-130 bar, the injection speed is set to be 10%-99% of the maximum speed, and the injection time is set to be in the range of 2-10 seconds.

[0052] (2) The bag preform prepared in step (1) is directly transferred into the blow molding machine of the integrated machine without cooling and blow molded while hot, and then cooled to obtain an upright polypropylene infusion bag.

[0053] After testing, the upright polypropylene infusion bag prepared in this embodiment was found to be of acceptable appearance, with a self-draining time of 20 minutes and a light transmittance of 50%.

[0054] Example 5: Preparation of Upright Polypropylene Infusion Bag

[0055] (1) Pre-forming the preform: Install the preform mold on the one-step hollow molding machine, heat the barrel temperature of the one-step hollow molding machine to 180°C, add polypropylene (PP) material into the barrel of the one-step hollow molding machine, and inject the polypropylene (PP) material into the preform mold under high pressure after it enters the molten state. The preform is then prepared by pre-blowing with a blow molding machine. During the pre-blowing process, the main runner temperature is controlled at 180°C, the pre-blowing temperature is controlled at 100°C, and the blow molding temperature controller temperature is controlled at 40°C.

[0056] The mold-closing operation of the molten plastic barrel is divided into five stages: mold closing stage 1, mold closing stage 2, mold closing stage 3, mold closing low pressure, and mold closing high pressure. The mold opening operation of the molten plastic barrel is divided into five stages: mold opening slow speed, mold opening stage 2, mold opening stage 3, mold opening stage 4, and mold opening stage 5. The high pressure of mold closing is set within the range of 5-22MPa, and the low pressure of mold closing is set within the range of 1-10MPa.

[0057] When injecting molten polypropylene (PP) material into the preform mold under high pressure, the pressure of the first injection stage is set to be in the range of 30-200 bar, the pressure of the second injection stage is set to be in the range of 20-130 bar, the injection speed is set to be 10%-99% of the maximum speed, and the injection time is set to be in the range of 2-10 seconds.

[0058] (2) The bag preform prepared in step (1) is directly transferred into the blow molding machine of the integrated machine without cooling and blow molded while hot, and then cooled to obtain an upright polypropylene infusion bag.

[0059] After testing, the upright polypropylene infusion bag prepared in this embodiment was found to be of acceptable appearance, with a self-draining time of 20 minutes and a light transmittance of 50%.

Claims

1. A method for preparing an upright polypropylene infusion bag, characterized in that, include: (1) Pre-forming the preform: Install the preform mold on the one-step hollow molding machine, heat the barrel temperature of the one-step hollow molding machine to 220-230℃, add polypropylene (PP) material into the barrel of the one-step hollow molding machine, and inject the polypropylene (PP) material into the preform mold under high pressure after it enters the molten state. The preform is then prepared by pre-blowing with a blow molding machine. During the pre-blowing process, the main runner temperature and the barrel temperature are controlled between 220-230℃, the pre-blowing temperature is controlled at 160℃, and the blow molding temperature controller temperature is controlled between 60℃-70℃. (2) The bag preform prepared in step (1) is directly transferred into the blow molding machine of the integrated machine without cooling and blow molded while hot, and then cooled to obtain an upright polypropylene infusion bag.

2. The preparation method according to claim 1, characterized in that, Install a preform mold on a one-step hollow molding machine and heat the barrel temperature of the one-step hollow molding machine to 230℃. During the pre-blowing process, the main runner temperature is controlled at 230℃, the pre-blowing temperature is controlled at 160℃, and the blow molding temperature controller temperature is controlled at 70℃.

3. The preparation method according to claim 1, characterized in that, It also includes a mold-locking operation for the molten rubber cylinder, which is divided into five stages: mold-locking stage 1, mold-locking stage 2, mold-locking stage 3, mold-locking low pressure, and mold-locking high pressure; the mold-locking high pressure is set within the range of 5-22MPa, and the mold-locking low pressure is set within the range of 1-10MPa.

4. The preparation method according to claim 1, characterized in that, It also includes mold closing operations for the molten plastic cylinder. During the mold closing operation, the mold opening is divided into five stages: slow mold opening, two-stage mold opening, three-stage mold opening, four-stage mold opening, and five-stage mold opening.

5. The preparation method according to claim 1, characterized in that, When injecting molten polypropylene (PP) material into the preform mold under high pressure, the injection pressure of the first stage is set to be in the range of 30-200 bar, the injection pressure of the second stage is set to be in the range of 20-130 bar, the injection speed is set to be 10%-99% of the maximum speed, and the injection time is set to be in the range of 2-10 seconds.

6. The preparation method according to claim 1, characterized in that, During the bag forming process, a lifting ring structure is designed at the bottom of the bag preform mold, and the lifting ring and the bag preform are integrally injection molded.

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