A three-layer co-extruded infusion film for liquid-liquid multi-chamber bags and a method for preparing the same

Abstract

This application discloses a three-layer co-extruded infusion membrane for liquid-liquid multi-chamber bags and its preparation method. The three-layer co-extruded infusion membrane provided in this application comprises an outer layer, a middle layer, and an inner layer. The outer layer material is a mixture of homopolymer polypropylene, a low-ethylene-content ethylene-propylene polymer, and SEBS or SEPS. The middle layer material is a mixture of a high-ethylene-content ethylene-propylene polymer, a low-ethylene-propylene polymer, and SEBS or SEPS. The inner layer material is a mixture of an ethylene-propylene-butene polymer, a high-ethylene-content ethylene-propylene polymer, a low-ethylene-propylene polymer, and SEBS or SEPS. The infusion membrane provided in this application exhibits excellent flexibility, stable solid weld strength, and weak weld strength.

Description

Technical Field

[0001] This invention belongs to the field of medical packaging materials technology, specifically relating to a three-layer co-extruded infusion film for liquid-liquid multi-chamber bags and its preparation method. Background Technology

[0002] Multi-compartment infusion bags are made from multi-layer co-extruded infusion films through heat sealing. They are primarily constructed by using heat-sealing weak welding rods to divide the infusion bag into multiple independent compartments, with the medication placed in each compartment under strict aseptic conditions. In clinical use, healthcare professionals open the weak welding rods by squeezing, allowing the medication in adjacent compartments to mix, achieving drug compatibility in a closed environment. This eliminates microbial contamination and drug errors during drug preparation, and also shortens preparation time, making it more convenient and efficient to use.

[0003] Multi-compartment bags for liquid infusion typically range in size from 500ml to 2000ml, thus placing higher performance demands on the multilayer co-extruded film used in flexible infusion packaging. The film must ensure high strength in the welded edges around the multi-compartment bag to guarantee its airtightness, while also maintaining stable strength between the weaker welds of adjacent compartments even after high-temperature sterilization, allowing for easy opening and mixing of medications. Due to the large size of the medications, the film must also prevent damage and leakage from impacts during production, transportation, and use, requiring excellent toughness.

[0004] Currently, the main types of membranes used for infusion on the market are three-layer co-extruded infusion membranes and five-layer co-extruded infusion membranes. Five-layer membranes generally require the use of polar adhesive resins, which reduces the compatibility between the membrane material and the drugs, limiting the range of applications and the types of drugs that can be used. Furthermore, the equipment and raw material costs for five-layer membranes are higher, resulting in higher membrane material costs.

[0005] The existing three-layer membranes generally use polypropylene with low ethylene content in each layer for film formation. The membrane material has poor toughness, a narrow heat-sealing window, and is difficult to provide stable weak weld strength. The weak weld strength before and after sterilization varies greatly. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a three-layer co-extruded infusion membrane for liquid-liquid multi-chamber bags, which uses high ethylene content polypropylene to solve the problem of poor toughness of existing three-layer co-extruded infusion membranes; and uses polypropylene with different melting points to solve the problems of narrow heat-sealing windows, difficulty in providing stable weak weld strength, and large difference in weak weld strength before and after sterilization.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A three-layer co-extruded infusion membrane for multi-chamber bags, characterized in that it comprises a three-layer structure consisting of an outer layer, a middle layer, and an inner layer, wherein:

[0009] Outer layer: The outer layer material is a mixture of homopolymer polypropylene, low-ethylene-content ethylene-propylene polymer, and styrene-ethylene-butene-styrene block copolymer (hereinafter referred to as SEBS) or styrene-ethylene-propylene-styrene block copolymer (hereinafter referred to as SEPS); wherein the content of homopolymer polypropylene is between 60% and 90%, the content of low-ethylene-content ethylene-propylene polymer is between 5% and 20%, and the content of SEBS or SEPS is between 5% and 20%; the outer layer mainly provides good printability, scratch resistance, and high-temperature sterilization resistance;

[0010] Middle layer: The middle layer material is a mixture of high-ethylene-content ethylene-propylene polymer, low-ethylene-content ethylene-propylene polymer, and SEBS or SEPS; wherein the high-ethylene-content ethylene-propylene polymer content is between 15% and 45%, the low-ethylene-content ethylene-propylene polymer content is between 10% and 30%, and the SEBS or SEPS content is between 25% and 65%; the middle layer mainly provides good flexibility and low-temperature impact resistance.

[0011] Inner layer: The inner layer material is a mixture of ethylene-propylene-butene polymer, high-ethylene-content ethylene-propylene polymer, low-ethylene-content ethylene-propylene polymer, and SEBS or SEPS; wherein the content of ethylene-propylene-butene polymer is between 10% and 20%, the content of high-ethylene-content ethylene-propylene polymer is between 40% and 70%, the content of low-ethylene-content ethylene-propylene polymer is between 10% and 30%, and the content of SEBS or SEPS is between 10% and 30%; the inner layer is in contact with the drug and has good drug compatibility, flexibility, and weak weld strength stability.

[0012] In some embodiments, the outer layer material contains 60%–80% homopolymer polypropylene, 10%–20% low-ethylene-content ethylene-propylene polymer, and 10%–20% SEBS or SEPS.

[0013] Preferably, the outer layer material contains 60% or 80% homopolymer polypropylene, 10% or 20% low-ethylene-content ethylene-propylene polymer, and 10% or 20% SEBS or SEPS.

[0014] In some embodiments, the outer layer material contains 80% homopolymer polypropylene, 10% low-ethylene ethylene-propylene polymer, and 10% SEBS or SEPS.

[0015] In some embodiments, the middle layer material contains 15%, 30%, or 45% high-ethylene-content ethylene-propylene polymer, 10%, 25%, or 30% low-ethylene-content ethylene-propylene polymer, and 30%, 55%, or 60% SEBS or SEPS.

[0016] In some embodiments, the middle layer material contains 15% high-ethylene-content ethylene-propylene polymer, 30% low-ethylene-content ethylene-propylene polymer, and 55% SEBS or SEPS.

[0017] In some embodiments, the inner layer material contains 10% or 20% ethylene-propylene-butene polymer, 40% high-ethylene-content ethylene-propylene polymer, 20% or 30% low-ethylene-content ethylene-propylene polymer, and 20% SEBS or SEPS.

[0018] In some embodiments, the inner layer material contains 10% ethylene-propylene-butene polymer, 40% high-ethylene-content ethylene-propylene polymer, 30% low-ethylene-content ethylene-propylene polymer, and 20% SEBS or SEPS.

[0019] The "content" in the outer, middle, and inner layer materials mentioned above all refer to a percentage by mass.

[0020] In some embodiments, the outer layer uses homopolymer polypropylene with a melting point of 160-165°C and a melt index of 3.0 g / 10 min to 8.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has a melting point of 150-155°C and a melt index of 2.0 g / 10 min to 8.0 g / 10 min; the SEBS melt index is 2.0-5.0 g / 10 min; and the SEPS melt index is 2.0-5.0 g / 10 min.

[0021] In some embodiments, the high-ethylene-content ethylene-propylene polymer used in the middle layer has a melting point of 135-150°C and a melt index of 3.0 g / 10 min to 6.0 g / (min); the low-ethylene-content ethylene-propylene polymer used has a melting point of 150-155°C and a melt index of 2.0 g / 10 min to 8.0 g / 10 min; the SEBS melt index is 2.0-5.0 g / 10 min; and the SEPS melt index is 2.0-5.0 g / 10 min.

[0022] In some embodiments, the inner layer uses a high-ethylene-content ethylene-propylene polymer with a melting point of 135-150°C and a melt index of 3.0 g / 10 min to 6.0 g / 10 min; a low-ethylene-content ethylene-propylene polymer with a melting point of 150-155°C and a melt index of 2.0 g / 10 min to 8.0 g / 10 min; an ethylene-propylene-butene polymer with a melting point of 130-135°C and a melt index of 6.0 g / 10 min to 8.0 g / 10 min; the SEBS melt index is 2.0-5.0 g / 10 min; and the SEPS melt index is 2.0-5.0 g / 10 min.

[0023] In some embodiments, the ethylene content in the high-ethylene-content ethylene-propylene polymer is 5%-15%; the ethylene content in the low-ethylene-content ethylene-propylene polymer is below 3%.

[0024] In some implementation schemes, the materials constituting the outer, middle, and inner layers of the three-layer co-extruded infusion membrane for multi-chamber bags provided in this application are all medical grade.

[0025] In some embodiments, the three-layer co-extruded infusion membrane for liquid-liquid multi-chamber bags provided in this application has the following thickness percentages for the outer, middle, and inner layers: 12%-16%, 68%-76%, and 12%-16%, respectively; preferably, the thickness percentages for the outer, middle, and inner layers are 15%, 70%, and 15%, respectively.

[0026] In some embodiments, the liquid-liquid multi-chamber bag three-layer co-extruded infusion membrane provided in this application has a total thickness of 180μm-250μm for the three-layer structure.

[0027] In a second aspect, this application provides a method for preparing the above-mentioned three-layer co-extruded infusion membrane for liquid-liquid multi-chamber bags. The method is as follows: the production equipment is a down-blown water-cooled three-layer co-extrusion blown film unit. The outer layer material, the middle layer material, and the inner layer material are respectively placed into the corresponding extruder hoppers of the three-layer co-extrusion blown film machine. After each layer material is extruded by the extruder screw, the film preform is blown down by the die head to form a film bubble. Then, it is water-cooled, shaped, wound, and slit to obtain the final product.

[0028] In some embodiments, the preparation method includes an outer extruder temperature of 190℃-220℃, a middle extruder temperature of 185℃-215℃, an inner extruder temperature of 170℃-200℃, and a die temperature of 190℃-220℃.

[0029] In some embodiments, the preparation method involves blowing the membrane preform into a membrane bubble through a die head, followed by cooling with purified water, wherein the blow-up ratio is 0.8-3.0 and the water temperature is 8℃-20℃.

[0030] In some embodiments, in the preparation method, after the membrane bubble is integrated and shaped by the herringbone plate, the membrane material is pulled by the traction roller and enters the winding roller for winding, wherein the tension of the traction roller is 8-20 kg and the winding speed is 4-15 m / min.

[0031] In some embodiments, the three-layer co-extruded infusion membrane for liquid-liquid multi-chamber bags provided in this application is prepared by the above method, wherein the actual welding temperature is 145-155℃, the actual welding strength is greater than 40N / 15mm, the weak welding temperature is 120-135℃, and the weak welding strength is between 5-15N / 15mm.

[0032] The present invention has the following beneficial effects:

[0033] (1) The inner and middle layers of this invention are made of ethylene-propylene polymer with high ethylene content, which makes the infusion membrane exhibit better flexibility than other three-layer co-extruded infusion membranes. Even in environments below 0°C, the membrane material has good low-temperature impact resistance and physical and mechanical properties. It can be used for packaging infusion products with specifications of 1000-3000ml, reducing the risk of leakage during product production, transportation and use.

[0034] (2) The inner layer material of the present invention is made of polymers with different melting points, which has a wide heat sealing window, and has weak welding heat sealing performance with a heat sealing strength of 5-15N / 15mm and solid welding heat sealing performance with a heat sealing strength greater than 40N / 15mm, thus meeting the process requirements of peripheral solid welding and central weak welding.

[0035] (3) The present invention can withstand high temperature sterilization at 121°C for 12 minutes. The weak weld strength and the actual weld strength are stable before and after sterilization and will not change significantly.

[0036] (4) The present invention adopts a three-layer structure, which is simpler to prepare than the five-layer co-extruded infusion membrane, and has lower equipment cost, energy cost and raw material cost.

[0037] (5) The present invention adopts a three-layer structure. Compared with the five-layer co-extruded infusion membrane, it does not use adhesives, does not contain polar materials, and has better drug compatibility. Attached Figure Description

[0038] Figure 1 This is a structural diagram of the three-layer co-extruded membrane for fluid delivery according to the present invention. Detailed Implementation

[0039] The following detailed description of specific embodiments further illustrates the above-described content of the present invention. However, it should not be construed as limiting the scope of the present invention to the following examples. All technical solutions implemented based on the above-described content of the present invention fall within the scope of the present invention.

[0040] As defined herein, the "melt index," also known as the "melt flow index," is an indicator characterizing the fluidity and processability of plastic materials. It refers to the weight of a thermoplastic resin or plastic melt flowing through a standard capillary tube within a specified time under a given temperature and constant load, expressed in g / 10min.

[0041] As defined herein, “homogeneous polypropylene” is polymerized from a single propylene monomer and does not contain other monomers in its molecular chain.

[0042] As defined herein, the “low-ethylene-content ethylene-propylene polymer” is a polymer co-polymerized from propylene and ethylene monomers, wherein the ethylene content is less than 3%.

[0043] As defined herein, the “high ethylene content ethylene-propylene polymer” is a polymer co-polymerized from two monomers, propylene and ethylene, wherein the ethylene content is between 5% and 15%.

[0044] As defined herein, the “ethylene-propylene-butene polymer” is a polymer formed by the co-polymerization of three monomers: ethylene, propylene, and butene.

[0045] As defined herein, “styrene-ethylene-butene-styrene block copolymer (SEBS)” is a linear block copolymer with polystyrene as the end block and ethylene-butene copolymer obtained by hydrogenating polybutadiene as the middle elastic block.

[0046] As defined herein, “styrene-ethylene-propylene-styrene block copolymer (SEPS)” is a block copolymer with polystyrene as the end block and ethylene-propylene copolymer obtained by hydrogenating polyisoprene as the middle elastic block.

[0047] Example 1

[0048] A three-layer co-extruded infusion membrane for multi-chamber bags, comprising an outer layer, a middle layer, and an inner layer:

[0049] Outer layer: 60% homopolymer polypropylene, 20% low-ethylene ethylene-propylene polymer, and 20% SEBS.

[0050] Middle layer: High ethylene content ethylene-propylene polymer content is 45%, low ethylene content ethylene-propylene polymer content is 25%, SEBS content is 30%;

[0051] Inner layer: 20% ethylene-propylene-butene polymer content, 40% high ethylene content ethylene-propylene polymer content, 20% low ethylene content ethylene-propylene polymer content, and 20% SEBS content;

[0052] The homopolymer polypropylene used in the outer layer has a melting point of 164°C and a melt index of 3.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has an ethylene content of 2%, a melting point of 150°C, and a melt index of 2.0 g / 10 min.

[0053] The high-ethylene-content ethylene-propylene polymer used in the above-mentioned middle layer has an ethylene content of 15%, a melting point of 150℃, and a melt index of 4.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has an ethylene content of 2%, a melting point of 150℃, and a melt index of 2.0 g / 10 min.

[0054] The inner layer uses a high-ethylene-content ethylene-propylene polymer with an ethylene content of 15%, a melting point of 139°C, and a melt index of 3.0 g / 10 min; a low-ethylene-content ethylene-propylene polymer with an ethylene content of 2%, a melting point of 150°C, and a melt index of 2.0 g / 10 min; and an ethylene-propylene-butene polymer with a melting point of 130°C and a melt index of 8.0 g / 10 min.

[0055] The melt index of SEBS used in the outer, middle and inner layers is 2.2 g / 10 min.

[0056] The materials constituting the outer, middle, and inner layers are all medical grade; in the three-layer structure, the thickness ratios of the outer, middle, and inner layers are 15%, 70%, and 15%, respectively; the total thickness of the three-layer structure is 200μm.

[0057] The preparation method of the above-mentioned liquid-liquid multi-chamber bag three-layer co-extrusion infusion membrane is as follows: the production equipment is a down-blown water-cooled three-layer co-extrusion blown film unit. The outer layer material, middle layer material and inner layer material are respectively put into the corresponding extruder hopper of the three-layer co-extrusion blown film machine. After each layer material is extruded by the extruder screw, the film preform is blown down by the die head to form a film bubble. Then, it is water-cooled, shaped, wound up and cut to obtain the membrane.

[0058] In the preparation method, the outer extruder temperature is 190℃-220℃, the middle extruder temperature is 185℃-215℃, the inner extruder temperature is 170℃-200℃, and the die temperature is 190℃-220℃.

[0059] In the preparation method, the membrane preform is blown down through a die to form a membrane bubble, and then cooled with purified water, wherein the blow-up ratio is 1.6 and the water temperature is 15°C;

[0060] In the preparation method, after the membrane bubble is integrated and shaped by the herringbone plate, the membrane material is pulled by the traction roller and enters the winding roller for winding. The tension of the traction roller is 14 kg and the winding speed is 10 m / min.

[0061] The obtained infusion membrane has a solid welding temperature of 145℃ and a strength of 51.5N, and a weak welding temperature of 125℃ and a strength of 11.2N.

[0062] Example 2

[0063] A three-layer co-extruded infusion membrane for multi-chamber bags, comprising an outer layer, a middle layer, and an inner layer:

[0064] Outer layer: 60% homopolymer polypropylene, 20% low-ethylene ethylene-propylene polymer, and 20% SEBS.

[0065] Middle layer: High ethylene content ethylene-propylene polymer content is 30%, low ethylene content ethylene-propylene polymer content is 10%, SEBS content is 60%;

[0066] Inner layer: 10% ethylene-propylene-butene polymer content, 40% high ethylene content ethylene-propylene polymer content, 30% low ethylene content ethylene-propylene polymer content, and 20% SEBS content;

[0067] The homopolymer polypropylene used in the outer layer has a melting point of 164°C and a melt index of 3.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has an ethylene content of 3%, a melting point of 150°C, and a melt index of 2.0 g / 10 min.

[0068] The high-ethylene-content ethylene-propylene polymer used in the above-mentioned middle layer has an ethylene content of 5%, a melting point of 150℃, and a melt index of 4.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has an ethylene content of 3%, a melting point of 150℃, and a melt index of 2.0 g / 10 min.

[0069] The high-ethylene-content ethylene-propylene polymer used in the inner layer has an ethylene content of 5%, a melting point of 150℃, and a melt index of 4.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer has an ethylene content of 3%, a melting point of 150℃, and a melt index of 2.0 g / 10 min; and the ethylene-propylene-butene polymer has a melting point of 130℃ and a melt index of 8.0 g / 10 min.

[0070] The melt index of SEBS used in the outer, middle and inner layers is 4.5 g / 10 min.

[0071] The materials constituting the outer, middle, and inner layers are all medical grade; in the three-layer structure, the thickness ratios of the outer, middle, and inner layers are 15%, 70%, and 15%, respectively; the total thickness of the three-layer structure is 200μm.

[0072] The preparation method of the above-mentioned liquid-liquid multi-chamber bag three-layer co-extrusion infusion membrane is as follows: the production equipment is a down-blown water-cooled three-layer co-extrusion blown film unit. The outer layer material, middle layer material and inner layer material are respectively put into the corresponding extruder hopper of the three-layer co-extrusion blown film machine. After each layer material is extruded by the extruder screw, the film preform is blown down by the die head to form a film bubble. Then, it is water-cooled, shaped, wound up and cut to obtain the membrane.

[0073] In the preparation method, the outer extruder temperature is 190℃-220℃, the middle extruder temperature is 185℃-215℃, the inner extruder temperature is 170℃-200℃, and the die temperature is 190℃-220℃.

[0074] In the preparation method, the membrane preform is blown down through a die to form a membrane bubble, and then cooled with purified water, wherein the blow-up ratio is 1.6 and the water temperature is 15°C;

[0075] In the preparation method, after the membrane bubble is integrated and shaped by the herringbone plate, the membrane material is pulled by the traction roller and enters the winding roller for winding. The tension of the traction roller is 14 kg and the winding speed is 10 m / min.

[0076] The obtained infusion membrane has a solid welding temperature of 150℃ and a strength of 48.6N, and a weak welding temperature of 131℃ and a strength of 10.8N.

[0077] Example 3

[0078] A three-layer co-extruded infusion membrane for multi-chamber bags, comprising an outer layer, a middle layer, and an inner layer:

[0079] Outer layer: 80% homopolymer polypropylene, 10% low-ethylene ethylene-propylene polymer, and 10% SEBS.

[0080] Middle layer: High ethylene content ethylene-propylene polymer content is 15%, low ethylene content ethylene-propylene polymer content is 30%, SEBS content is 55%;

[0081] Inner layer: 10% ethylene-propylene-butene polymer content, 40% high ethylene content ethylene-propylene polymer content, 30% low ethylene content ethylene-propylene polymer content, and 20% SEBS content;

[0082] The homopolymer polypropylene used in the outer layer has a melting point of 165°C and a melt index of 8.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has an ethylene content of 3%, a melting point of 151°C, and a melt index of 8.0 g / 10 min.

[0083] The high-ethylene-content ethylene-propylene polymer used in the above-mentioned middle layer has an ethylene content of 12%, a melting point of 139℃, and a melt index of 3.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has an ethylene content of 3%, a melting point of 151℃, and a melt index of 8.0 g / 10 min.

[0084] The high-ethylene-content ethylene-propylene polymer used in the inner layer has an ethylene content of 12%, a melting point of 150℃, and a melt index of 4.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer has an ethylene content of 3%, a melting point of 151℃, and a melt index of 8.0 g / 10 min; and the ethylene-propylene-butene polymer has a melting point of 130℃ and a melt index of 8.0 g / 10 min.

[0085] The melt index of SEBS used in the outer, middle and inner layers is 2.2 g / 10 min.

[0086] The materials constituting the outer, middle, and inner layers are all medical grade; in the three-layer structure, the thickness ratios of the outer, middle, and inner layers are 15%, 70%, and 15%, respectively; the total thickness of the three-layer structure is 200μm.

[0087] The preparation method of the above-mentioned liquid-liquid multi-chamber bag three-layer co-extrusion infusion membrane is as follows: the production equipment is a down-blown water-cooled three-layer co-extrusion blown film unit. The outer layer material, middle layer material and inner layer material are respectively put into the corresponding extruder hopper of the three-layer co-extrusion blown film machine. After each layer material is extruded by the extruder screw, the film preform is blown down by the die head to form a film bubble. Then, it is water-cooled, shaped, wound up and cut to obtain the membrane.

[0088] In the preparation method, the outer extruder temperature is 190℃-220℃, the middle extruder temperature is 185℃-215℃, the inner extruder temperature is 170℃-200℃, and the die temperature is 190℃-220℃.

[0089] In the preparation method, the membrane preform is blown down through a die to form a membrane bubble, and then cooled with purified water, wherein the blow-up ratio is 1.6 and the water temperature is 15°C;

[0090] In the preparation method, after the membrane bubble is integrated and shaped by the herringbone plate, the membrane material is pulled by the traction roller and enters the winding roller for winding. The tension of the traction roller is 14 kg and the winding speed is 10 m / min.

[0091] The obtained infusion membrane has a solid welding temperature of 151℃ and a strength of 48.2N, and a weak welding temperature of 130℃ and a strength of 11.0N.

[0092] Example 4

[0093] A three-layer co-extruded infusion membrane for multi-chamber bags, comprising an outer layer, a middle layer, and an inner layer:

[0094] Outer layer: 80% homopolymer polypropylene, 10% low-ethylene ethylene-propylene polymer, and 10% SEBS;

[0095] Middle layer: High ethylene content ethylene-propylene polymer content is 15%, low ethylene content ethylene-propylene polymer content is 30%, SEBS content is 55%;

[0096] Inner layer: 10% ethylene-propylene-butene polymer content, 40% high ethylene content ethylene-propylene polymer content, 30% low ethylene content ethylene-propylene polymer content, and 20% SEBS content;

[0097] The homopolymer polypropylene used in the outer layer has a melting point of 165°C and a melt index of 8.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has an ethylene content of 2%, a melting point of 151°C, and a melt index of 8.0 g / 10 min.

[0098] The high-ethylene-content ethylene-propylene polymer used in the above-mentioned middle layer has an ethylene content of 8%, a melting point of 139°C, and a melt index of 3.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has an ethylene content of 2%, a melting point of 151°C, and a melt index of 8.0 g / 10 min.

[0099] The inner layer uses a high-ethylene-content ethylene-propylene polymer with an ethylene content of 8%, a melting point of 139°C, and a melt index of 3.0 g / 10 min; a low-ethylene-content ethylene-propylene polymer with an ethylene content of 2%, a melting point of 151°C, and a melt index of 8.0 g / 10 min; and an ethylene-propylene-butene polymer with a melting point of 130°C and a melt index of 8.0 g / 10 min.

[0100] The melt index of SEBS used in the outer, middle and inner layers is 2.2 g / 10 min.

[0101] The materials constituting the outer, middle, and inner layers are all medical grade; in the three-layer structure, the thickness ratios of the outer, middle, and inner layers are 15%, 70%, and 15%, respectively; the total thickness of the three-layer structure is 200μm.

[0102] The preparation method of the above-mentioned liquid-liquid multi-chamber bag three-layer co-extrusion infusion membrane is as follows: the production equipment is a down-blown water-cooled three-layer co-extrusion blown film unit. The outer layer material, middle layer material and inner layer material are respectively put into the corresponding extruder hopper of the three-layer co-extrusion blown film machine. After each layer material is extruded by the extruder screw, the film preform is blown down by the die head to form a film bubble. Then, it is water-cooled, shaped, wound up and cut to obtain the membrane.

[0103] In the preparation method, the outer extruder temperature is 190℃-220℃, the middle extruder temperature is 185℃-215℃, the inner extruder temperature is 170℃-200℃, and the die temperature is 190℃-220℃.

[0104] In the preparation method, the membrane preform is blown down through a die to form a membrane bubble, and then cooled with purified water, wherein the blow-up ratio is 1.6 and the water temperature is 15°C;

[0105] In the preparation method, after the membrane bubble is integrated and shaped by the herringbone plate, the membrane material is pulled by the traction roller and enters the winding roller for winding. The tension of the traction roller is 14 kg and the winding speed is 10 m / min.

[0106] The obtained infusion membrane has a solid welding temperature of 146℃ and a strength of 50.8N, and a weak welding temperature of 124℃ and a strength of 10.5N.

[0107] Example 5

[0108] A three-layer co-extruded infusion membrane for multi-chamber bags, comprising an outer layer, a middle layer, and an inner layer:

[0109] Outer layer: 60% homopolymer polypropylene, 20% low-ethylene ethylene-propylene polymer, and 20% SEBS.

[0110] Middle layer: High ethylene content ethylene-propylene polymer content is 45%, low ethylene content ethylene-propylene polymer content is 25%, SEBS content is 30%;

[0111] Inner layer: 20% ethylene-propylene-butene polymer content, 40% high ethylene content ethylene-propylene polymer content, 20% low ethylene content ethylene-propylene polymer content, and 20% SEBS content;

[0112] The homopolymer polypropylene used in the outer layer has a melting point of 164°C and a melt index of 3.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has an ethylene content of 2%, a melting point of 150°C, and a melt index of 2.0 g / 10 min.

[0113] The high-ethylene-content ethylene-propylene polymer used in the above-mentioned middle layer has an ethylene content of 8%, a melting point of 150℃, and a melt index of 4.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has an ethylene content of 2%, a melting point of 150℃, and a melt index of 2.0 g / 10 min.

[0114] The high-ethylene-content ethylene-propylene polymer used in the inner layer has an ethylene content of 8%, a melting point of 139°C, and a melt index of 3.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer has an ethylene content of 2%, a melting point of 150°C, and a melt index of 2.0 g / 10 min; and the ethylene-propylene-butene polymer has a melting point of 130°C and a melt index of 8.0 g / 10 min.

[0115] The melt index of SEBS used in the outer, middle and inner layers is 4.5 g / 10 min.

[0116] The materials constituting the outer, middle, and inner layers are all medical grade; in the three-layer structure, the thickness ratios of the outer, middle, and inner layers are 15%, 70%, and 15%, respectively; the total thickness of the three-layer structure is 250μm.

[0117] The preparation method of the above-mentioned liquid-liquid multi-chamber bag three-layer co-extrusion infusion membrane is as follows: the production equipment is a down-blown water-cooled three-layer co-extrusion blown film unit. The outer layer material, middle layer material and inner layer material are respectively put into the corresponding extruder hopper of the three-layer co-extrusion blown film machine. After each layer material is extruded by the extruder screw, the film preform is blown down by the die head to form a film bubble. Then, it is water-cooled, shaped, wound up and cut to obtain the membrane.

[0118] In the preparation method, the outer extruder temperature is 190℃-220℃, the middle extruder temperature is 185℃-215℃, the inner extruder temperature is 170℃-200℃, and the die temperature is 190℃-220℃.

[0119] In the preparation method, the membrane preform is blown down through a die to form a membrane bubble, and then cooled with purified water, wherein the blow-up ratio is 1.6 and the water temperature is 15°C;

[0120] In the preparation method, after the membrane bubble is integrated and shaped by the herringbone plate, the membrane material is pulled by the traction roller and enters the winding roller for winding. The tension of the traction roller is 13 kg and the winding speed is 8 m / min.

[0121] The obtained infusion membrane has a solid welding temperature of 145℃ and a strength of 50.6N, and a weak welding temperature of 125℃ and a strength of 10.9N.

[0122] Experimental Example 1

[0123] The five embodiments described above were tested according to the methods and indicators specified in the standard YBB00102005-2015 Three-layer co-extruded infusion membrane (I) and bag, and the following technical data were obtained:

[0124] Standards and methods for testing actual weld strength: Take several of these products and test them according to the method for composite bags in the heat-sealed strength test method (YBB00122003-2015). The average value of the heat-sealed parts shall not be less than 20N / 15mm.

[0125] Weak weld strength testing standard: The testing method is YBB00122003-2015.

[0126] Table 1

[0127]

[0128] The three-layer co-extruded infusion film for liquid-liquid multi-chamber bags prepared in this application meets all the requirements of the national pharmaceutical packaging material standards. In particular, it has excellent drop resistance and tensile strength. The weak weld strength and solid weld strength remain stable before and after sterilization, making it very suitable for large-size liquid-liquid multi-chamber bags.

[0129] Comparative Example 1

[0130] A three-layer co-extruded infusion membrane for multi-chamber bags, comprising an outer layer, a middle layer, and an inner layer:

[0131] Outer layer: 60% homopolymer polypropylene, 20% low-ethylene ethylene-propylene polymer, and 20% SEBS.

[0132] Middle layer: Low ethylene content, ethylene-propylene polymer content is 50%, SEBS content is 50%;

[0133] Inner layer: 20% ethylene-propylene-butene polymer content, 60% low-ethylene ethylene-propylene polymer content, and 20% SEBS content;

[0134] The homopolymer polypropylene used in the outer layer has a melting point of 164°C and a melt index of 3.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has a melting point of 150°C and a melt index of 2.0 g / 10 min.

[0135] The low-ethylene-propylene polymer used in the above-mentioned middle layer has a melting point of 150°C and a melt index of 2.0 g / 10 min.

[0136] The low-ethylene-content ethylene-propylene polymer used in the inner layer has a melting point of 150°C and a melt index of 2.0 g / 10 min; the ethylene-propylene-butene polymer used has a melting point of 130°C and a melt index of 8.0 g / 10 min.

[0137] The melt index of SEBS used in the outer, middle and inner layers is 2.2 g / 10 min.

[0138] The materials constituting the outer, middle, and inner layers are all medical grade; in the three-layer structure, the thickness ratios of the outer, middle, and inner layers are 15%, 70%, and 15%, respectively; the total thickness of the three-layer structure is 200μm.

[0139] The preparation method of the above-mentioned liquid-liquid multi-chamber bag three-layer co-extrusion infusion membrane is as follows: the production equipment is a down-blown water-cooled three-layer co-extrusion blown film unit. The outer layer material, middle layer material and inner layer material are respectively put into the corresponding extruder hopper of the three-layer co-extrusion blown film machine. After each layer material is extruded by the extruder screw, the film preform is blown down by the die head to form a film bubble. Then, it is water-cooled, shaped, wound up and cut to obtain the membrane.

[0140] In the preparation method, the outer extruder temperature is 190℃-220℃, the middle extruder temperature is 185℃-215℃, the inner extruder temperature is 170℃-200℃, and the die temperature is 190℃-220℃.

[0141] In the preparation method, the membrane preform is blown down through a die to form a membrane bubble, and then cooled with purified water, wherein the blow-up ratio is 1.6 and the water temperature is 15°C;

[0142] In the preparation method, after the membrane bubble is integrated and shaped by the herringbone plate, the membrane material is pulled by the traction roller and enters the winding roller for winding. The tension of the traction roller is 14 kg and the winding speed is 10 m / min.

[0143] The obtained infusion membrane has a solid welding temperature of 145℃ and a strength of 52.0N, and a weak welding temperature of 132℃ and a strength of 11.5N.

[0144] The prepared three-layer co-extruded infusion membrane was subjected to drop tests. The number of drop tests was 13. It showed poor toughness, poor drop resistance, and easy breakage.

[0145] Comparative Example 2

[0146] A three-layer co-extruded infusion membrane for multi-chamber bags, comprising an outer layer, a middle layer, and an inner layer:

[0147] Outer layer: 60% homopolymer polypropylene, 20% low-ethylene ethylene-propylene polymer, and 20% SEBS.

[0148] Middle layer: High ethylene content ethylene-propylene polymer content is 10%, low ethylene content ethylene-propylene polymer content is 40%, SEBS content is 50%;

[0149] Inner layer: 10% ethylene-propylene-butene polymer content, 10% high ethylene content ethylene-propylene polymer content, 50% low ethylene content ethylene-propylene polymer content, and 20% SEBS content;

[0150] The homopolymer polypropylene used in the outer layer has a melting point of 164°C and a melt index of 3.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has a melting point of 150°C and a melt index of 2.0 g / 10 min.

[0151] The high-ethylene-propylene polymer used in the above-mentioned middle layer has a melting point of 150°C and a melt index of 4.0 g / 10 min; the low-ethylene-propylene polymer used has a melting point of 150°C and a melt index of 2.0 g / 10 min.

[0152] The high-ethylene-content ethylene-propylene polymer used in the inner layer has a melting point of 150°C and a melt index of 4.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has a melting point of 150°C and a melt index of 2.0 g / 10 min; and the ethylene-propylene-butene polymer used has a melting point of 130°C and a melt index of 8.0 g / 10 min.

[0153] The melt index of SEBS used in the outer, middle and inner layers is 2.2 g / 10 min.

[0154] The materials constituting the outer, middle, and inner layers are all medical grade; in the three-layer structure, the thickness ratios of the outer, middle, and inner layers are 15%, 70%, and 15%, respectively; the total thickness of the three-layer structure is 200μm.

[0155] The preparation method of the above-mentioned liquid-liquid multi-chamber bag three-layer co-extrusion infusion membrane is as follows: the production equipment is a down-blown water-cooled three-layer co-extrusion blown film unit. The outer layer material, middle layer material and inner layer material are respectively put into the corresponding extruder hopper of the three-layer co-extrusion blown film machine. After each layer material is extruded by the extruder screw, the film preform is blown down by the die head to form a film bubble. Then, it is water-cooled, shaped, wound up and cut to obtain the membrane.

[0156] In the preparation method, the outer extruder temperature is 190℃-220℃, the middle extruder temperature is 185℃-215℃, the inner extruder temperature is 170℃-200℃, and the die temperature is 190℃-220℃.

[0157] In the preparation method, the membrane preform is blown down through a die to form a membrane bubble, and then cooled with purified water, wherein the blow-up ratio is 1.6 and the water temperature is 15°C;

[0158] In the preparation method, after the membrane bubble is integrated and shaped by the herringbone plate, the membrane material is pulled by the traction roller and enters the winding roller for winding. The tension of the traction roller is 14 kg and the winding speed is 10 m / min.

[0159] The obtained infusion membrane has a solid welding temperature of 150℃ and a strength of 51.6, and a weak welding temperature of 130.5℃ and a strength of 10.6N.

[0160] The prepared three-layer co-extruded infusion membrane was subjected to a drop test, with 20 drop tests conducted. The membrane showed poor toughness and drop resistance, and was prone to leakage and breakage.

[0161] Comparative Example 3

[0162] A three-layer co-extruded infusion membrane for multi-chamber bags, comprising an outer layer, a middle layer, and an inner layer:

[0163] Outer layer: 60% homopolymer polypropylene, 20% low-ethylene ethylene-propylene polymer, and 20% SEBS.

[0164] Middle layer: High ethylene content ethylene-propylene polymer content is 30%, low ethylene content ethylene-propylene polymer content is 10%, SEBS content is 60%;

[0165] Inner layer: 10% ethylene-propylene-butene polymer content, 40% high ethylene content ethylene-propylene polymer content, 45% low ethylene content ethylene-propylene polymer content, and 5% SEBS content;

[0166] The homopolymer polypropylene used in the outer layer has a melting point of 165°C and a melt index of 8.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has a melting point of 151°C and a melt index of 8.0 g / 10 min.

[0167] The high-ethylene-content ethylene-propylene polymer used in the above-mentioned middle layer has a melting point of 150℃ and a melt index of 4.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has a melting point of 151℃ and a melt index of 8.0 g / 10 min.

[0168] The high-ethylene-propylene polymer used in the inner layer has a melting point of 150°C and a melt index of 4.0 g / 10 min; the low-ethylene-propylene polymer used has a melting point of 151°C and a melt index of 8.0 g / 10 min; and the ethylene-propylene-butene polymer used has a melting point of 130°C and a melt index of 8.0 g / 10 min.

[0169] The melt index of SEBS used in the outer, middle and inner layers is 4.5 g / 10 min.

[0170] The materials constituting the outer, middle, and inner layers are all medical grade; in the three-layer structure, the thickness ratios of the outer, middle, and inner layers are 15%, 70%, and 15%, respectively; the total thickness of the three-layer structure is 200μm.

[0171] The preparation method of the above-mentioned liquid-liquid multi-chamber bag three-layer co-extrusion infusion membrane is as follows: the production equipment is a down-blown water-cooled three-layer co-extrusion blown film unit. The outer layer material, middle layer material and inner layer material are respectively put into the corresponding extruder hopper of the three-layer co-extrusion blown film machine. After each layer material is extruded by the extruder screw, the film preform is blown down by the die head to form a film bubble. Then, it is water-cooled, shaped, wound up and cut to obtain the membrane.

[0172] In the preparation method, the outer extruder temperature is 190℃-220℃, the middle extruder temperature is 185℃-215℃, the inner extruder temperature is 170℃-200℃, and the die temperature is 190℃-220℃.

[0173] In the preparation method, the membrane preform is blown down through a die to form a membrane bubble, and then cooled with purified water, wherein the blow-up ratio is 1.6 and the water temperature is 15°C;

[0174] In the preparation method, after the membrane bubble is integrated and shaped by the herringbone plate, the membrane material is pulled by the traction roller and enters the winding roller for winding. The tension of the traction roller is 14 kg and the winding speed is 10 m / min.

[0175] The obtained infusion membrane has a solid welding temperature of 150℃ and a strength of 48.6N, and a weak welding temperature of 132℃ and a strength of 9.5N.

[0176] The three-layer co-extruded infusion membrane prepared in this comparative example has a heat-sealing strength of 6.2N-12.3N at different weak weld sites, which varies greatly and the weak weld strength is unstable.

[0177] Comparative Example 4

[0178] A three-layer co-extruded infusion membrane for multi-chamber bags, comprising an outer layer, a middle layer, and an inner layer:

[0179] Outer layer: 60% homopolymer polypropylene, 20% low-ethylene ethylene-propylene polymer, and 20% SEBS.

[0180] Middle layer: High ethylene content ethylene-propylene polymer content is 45%, low ethylene content ethylene-propylene polymer content is 25%, SEBS content is 30%;

[0181] Inner layer: High ethylene content ethylene-propylene polymer content is 40%, low ethylene content ethylene-propylene polymer content is 20%, SEBS content is 20%;

[0182] The homopolymer polypropylene used in the outer layer has a melting point of 164°C and a melt index of 3.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has a melting point of 150°C and a melt index of 2.0 g / 10 min.

[0183] The high-ethylene-propylene polymer used in the above-mentioned middle layer has a melting point of 150°C and a melt index of 4.0 g / 10 min; the low-ethylene-propylene polymer used has a melting point of 150°C and a melt index of 2.0 g / 10 min.

[0184] The high-ethylene-content ethylene-propylene polymer used in the inner layer has a melting point of 150°C and a melt index of 4.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has a melting point of 150°C and a melt index of 2.0 g / 10 min.

[0185] The melt index of SEBS used in the outer, middle and inner layers is 4.5 g / 10 min.

[0186] The materials constituting the outer, middle, and inner layers are all medical grade; in the three-layer structure, the thickness ratios of the outer, middle, and inner layers are 15%, 70%, and 15%, respectively; the total thickness of the three-layer structure is 200μm.

[0187] The preparation method of the above-mentioned liquid-liquid multi-chamber bag three-layer co-extrusion infusion membrane is as follows: the production equipment is a down-blown water-cooled three-layer co-extrusion blown film unit. The outer layer material, middle layer material and inner layer material are respectively put into the corresponding extruder hopper of the three-layer co-extrusion blown film machine. After each layer material is extruded by the extruder screw, the film preform is blown down by the die head to form a film bubble. Then, it is water-cooled, shaped, wound up and cut to obtain the membrane.

[0188] In the preparation method, the outer extruder temperature is 190℃-220℃, the middle extruder temperature is 185℃-215℃, the inner extruder temperature is 170℃-200℃, and the die temperature is 190℃-220℃.

[0189] In the preparation method, the membrane preform is blown down through a die to form a membrane bubble, and then cooled with purified water, wherein the blow-up ratio is 1.6 and the water temperature is 15°C;

[0190] In the preparation method, after the membrane bubble is integrated and shaped by the herringbone plate, the membrane material is pulled by the traction roller and enters the winding roller for winding. The tension of the traction roller is 14 kg and the winding speed is 10 m / min.

[0191] The obtained infusion membrane has an actual welding temperature of 150℃ and a strength of 50.3N. There is no obvious weak welding temperature range, making it difficult to achieve weak welding within the strength requirements.

[0192] Comparative Example 5

[0193] A three-layer co-extruded infusion membrane for multi-chamber bags, comprising an outer layer, a middle layer, and an inner layer:

[0194] Outer layer: 80% homopolymer polypropylene, 10% low-ethylene ethylene-propylene polymer, and 10% SEBS.

[0195] Middle layer: High ethylene content, with 65% ethylene-propylene polymer and 35% SEBS;

[0196] Inner layer: ethylene-propylene-butene polymer content is 10%, high ethylene content ethylene-propylene polymer content is 60%, low ethylene content ethylene-propylene polymer content is 10%, SEBS content is 20%;

[0197] The homopolymer polypropylene used in the outer layer has a melting point of 165°C and a melt index of 8.0 g / 10 min; the low-ethylene-content ethylene-propylene polymer used has a melting point of 151°C and a melt index of 8.0 g / 10 min.

[0198] The high-ethylene-propylene polymer used in the above-mentioned middle layer has a melting point of 139°C and a melt index of 3.0 g / 10 min.

[0199] The high-ethylene-propylene polymer used in the inner layer has a melting point of 150°C and a melt index of 4.0 g / 10 min; the low-ethylene-propylene polymer used has a melting point of 151°C and a melt index of 8.0 g / 10 min; and the ethylene-propylene-butene polymer used has a melting point of 130°C and a melt index of 8.0 g / 10 min.

[0200] The melt index of SEBS used in the outer, middle and inner layers is 4.5 g / 10 min.

[0201] The materials constituting the outer, middle, and inner layers are all medical grade; in the three-layer structure, the thickness ratios of the outer, middle, and inner layers are 15%, 70%, and 15%, respectively; the total thickness of the three-layer structure is 200μm.

[0202] The preparation method of the above-mentioned liquid-liquid multi-chamber bag three-layer co-extrusion infusion membrane is as follows: the production equipment is a down-blown water-cooled three-layer co-extrusion blown film unit. The outer layer material, middle layer material and inner layer material are respectively put into the corresponding extruder hopper of the three-layer co-extrusion blown film machine. After each layer material is extruded by the extruder screw, the film preform is blown down by the die head to form a film bubble. Then, it is water-cooled, shaped, wound up and cut to obtain the membrane.

[0203] In the preparation method, the outer extruder temperature is 190℃-220℃, the middle extruder temperature is 185℃-215℃, the inner extruder temperature is 170℃-200℃, and the die temperature is 190℃-220℃.

[0204] In the preparation method, the membrane preform is blown down through a die to form a membrane bubble, and then cooled with purified water, wherein the blow-up ratio is 1.6 and the water temperature is 15°C;

[0205] In the preparation method, after the membrane bubble is integrated and shaped by the herringbone plate, the membrane material is pulled by the traction roller and enters the winding roller for winding. The tension of the traction roller is 14 kg and the winding speed is 10 m / min.

[0206] The obtained infusion membrane has a solid welding temperature of 150℃ and a strength of 48.8N, and a weak welding temperature of 130℃ and a strength of 10.6N.

[0207] The three-layer co-extruded infusion membrane prepared in this comparative example has a light transmittance of 83%, which is low and the membrane has a large haze, affecting the appearance of the membrane and making it difficult to inspect the product by light during the production process.

[0208] Experimental Example 2

[0209] The five comparative examples were tested according to the methods and indicators specified in the standard "YBB00102005-2015 Three-layer co-extruded infusion membrane (I) and bag", and the following technical data were obtained:

[0210] Standards and methods for testing actual weld strength: Take several of these products and test them according to the method for composite bags in the heat-sealed strength test method (YBB00122003-2015). The average value of the heat-sealed parts shall not be less than 20N / 15mm.

[0211] Weak weld strength testing standard: The testing method is YBB00122003-2015.

[0212] Table 2

[0213]

[0214]

[0215] The methods and products of this invention have been described through preferred embodiments. Those skilled in the art will readily be able to modify or appropriately alter and combine the methods and products described herein without departing from the content, spirit, and scope of this invention to achieve the technical requirements of this invention. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the spirit, scope, and content of this invention.

Claims

1. A three-layer co-extruded infusion film for liquid-liquid multi-chamber bags, characterized by, It consists of a three-layer structure comprising an outer layer, a middle layer, and an inner layer, wherein: The outer layer material is a mixture of homopolymer polypropylene, low-ethylene-content ethylene-propylene polymer, and styrene-ethylene-butene-styrene block copolymer SEBS or styrene-ethylene-propylene-styrene block copolymer SEPS; The middle layer material is a mixture of high-ethylene-content ethylene-propylene polymer, low-ethylene-content ethylene-propylene polymer, and SEBS or SEPS; The inner layer material is a mixture of ethylene-propylene-butene polymer, high ethylene content ethylene-propylene polymer, low ethylene content ethylene-propylene polymer and SEBS or SEPS; In the outer layer material, the content of homopolymer polypropylene is between 60% and 90%, the content of low ethylene content ethylene-propylene polymer is between 5% and 20%, and the content of SEBS or SEPS is between 5% and 20%. In the middle layer material, the content of high ethylene content ethylene-propylene polymer is between 15% and 45%, the content of low ethylene content ethylene-propylene polymer is between 10% and 30%, and the content of SEBS or SEPS is between 25% and 65%. In the inner layer material, the content of ethylene-propylene-butene polymer is between 10% and 20%, the content of high ethylene content ethylene-propylene polymer is between 40% and 70%, the content of low ethylene content ethylene-propylene polymer is between 10% and 30%, and the content of SEBS or SEPS is between 10% and 30%. The high-ethylene-content ethylene-propylene polymer has an ethylene content of 5%-15%; the low-ethylene-content ethylene-propylene polymer has an ethylene content of less than 3%.

2. The three-layer co-extruded film for infusion solution according to claim 1, characterized in that, In the outer layer material, the homopolymer polypropylene has a melting point of 160-165℃ and a melt index of 3.0g / 10min-8.0g / 10min; the low-ethylene-content ethylene-propylene polymer has a melting point of 150-155℃ and a melt index of 2.0g / 10min-8.0g / 10min; the SEBS has a melt index of 2.0-5.0g / 10min; and the SEPS has a melt index of 2.0-5.0g / 10min.

3. The three-layer co-extruded film for infusion solutions according to claim 1 or 2, characterized in that, In the intermediate layer material, the high-ethylene-content ethylene-propylene polymer has a melting point of 135-150℃ and a melt index of 3.0g / 10min-6.0g / 10min; the low-ethylene-content ethylene-propylene polymer has a melting point of 150-155℃ and a melt index of 2.0g / 10min-8.0g / 10min; the SEBS melt index is 2.0-5.0g / 10min; and the SEPS melt index is 2.0-5.0g / 10min.

4. The three-layer co-extruded infusion membrane according to claim 1 or 2, characterized in that, In the inner layer material, the high-ethylene-content ethylene-propylene polymer has a melting point of 135-150℃ and a melt index of 3.0g / 10min-6.0g / 10min; the low-ethylene-content ethylene-propylene polymer has a melting point of 150-155℃ and a melt index of 2.0g / 10min-8.0g / 10min; the ethylene-propylene-butene polymer has a melting point of 130-135℃ and a melt index of 6.0g / 10min-8.0g / 10min; the SEBS melt index is 2.0-5.0g / 10min; and the SEPS melt index is 2.0-5.0g / 10min.

5. The three-layer co-extruded infusion membrane according to claim 1 or 2, characterized in that, The materials constituting the outer, middle, and inner layers are all medical grade; and the thickness ratios of the outer, middle, and inner layers are 12%-16%, 68%-76%, and 12%-16%, respectively; the total thickness of the three-layer structure is 180μm-250μm.

6. The preparation method of the three-layer co-extruded infusion membrane for liquid-liquid multi-chamber bags according to any one of claims 1-5, the method is as follows: the production equipment is a down-blown water-cooled three-layer co-extrusion blown film unit, the outer layer material, the middle layer material and the inner layer material are respectively put into the corresponding extruder hopper of the three-layer co-extrusion blown film machine, the material of each layer is extruded by the screw of the extruder, the film preform is blown down by the die head to form a film bubble, and then water-cooled, shaped, wound and cut to obtain the membrane.

7. The preparation method according to claim 6, characterized in that, The outer extruder temperature is 190℃-220℃, the middle extruder temperature is 185℃-215℃, the inner extruder temperature is 170℃-200℃, and the die head temperature is 190℃-220℃.

8. The preparation method according to claim 6, characterized in that, The membrane preform is blown down by the die head to form a membrane bubble, which is then cooled with purified water. After the membrane bubble is integrated and shaped by the herringbone plate, the membrane material is pulled by the traction roller and enters the winding roller for winding.

9. The preparation method according to claim 8, characterized in that, The blow-out ratio is 0.8-3.0, the cooling water temperature is 8℃-20℃, the traction roller tension is 8-20kg, and the winding speed is 4-15m / min.

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