Blowing wear-resistant packaging film for containing liquid bag, preparation method of blowing wear-resistant packaging film and containing liquid bag

Abstract

The invention discloses a blown wear-resistant packaging film for a liquid packaging bag, a preparation method of the blown wear-resistant packaging film and the liquid packaging bag, and belongs to the technical field of packaging film preparation, the blown wear-resistant packaging film comprises a film body sequentially composed of an outer layer, a middle layer and an inner layer from outside to inside, and the blown wear-resistant packaging film is characterized in that the outer layer is prepared from 8-10 parts by mass of blow molding grade TPU and 0.5-1.5 parts by mass of a slipping agent; the middle layer is prepared from 8.5-10.5 parts by mass of first metallocene linear low-density polyethylene and 0.3-0.7 part by mass of PPA, the inner layer is prepared from 5-7 parts by mass of second metallocene linear low-density polyethylene, 1-2 parts by mass of first low-density polyethylene, 0.3-0.7 part by mass of PPA, 0.5-1.5 parts by mass of an anti-blocking agent and 0.5-1.5 parts by mass of a slipping agent, the mark of the first metallocene linear low-density polyethylene is XP8784ML, and the mark of the second metallocene linear low-density polyethylene is XP8784ML. The second metallocene linear low-density polyethylene has a lateral first long-chain branch, and the first low-density polyethylene has a lateral second long-chain branch. On the premise of meeting the high mechanical property requirement of the liquid bag, the film can be blown into the film, and the wear resistance of the film is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of packaging films, and particularly relates to a blown wear-resistant packaging film for a containerized liquid bag, a preparation method thereof, and a containerized liquid bag. Background Art

[0002] With the development of logistics transportation, liquids have gradually changed from pipeline transportation with high construction costs and limited routes to more flexible vehicle transportation. Due to the particularity of liquids as fluids, higher requirements are imposed on transportation equipment and transportation conditions. Currently, liquids are mainly transported by tanker trucks and containerized liquid bags. Among them, tanker truck transportation is completed using customized iron or aluminum tanker trucks, which have higher transportation costs and cannot control the temperature during transportation, easily resulting in liquid spoilage; while containerized liquid bag transportation is to fill the transported liquid into a liquid bag inside a container. The liquid bag can avoid safety problems such as liquid leakage and pollution, effectively prevent cross-contamination of goods, and has advantages such as lower costs and no need for cleaning compared to tanker trucks. Moreover, it is convenient to change transportation tools midway, improving the versatility and interchangeability in sea, land, and air transportation. Therefore, it has been widely used in the storage and transportation fields of non-hazardous liquid goods such as oils, syrups, and red wines.

[0003] During transportation, it is found that the liquid bag is easily worn, causing liquid leakage, which not only increases the loss of the transported liquid but also pollutes the container or other goods, increasing the additional cleaning cost. The invention patent with the publication number CN119036987A discloses a biaxially oriented PE film, a preparation method thereof, and an application. It consists of an outer layer, a middle layer, and an inner layer. The outer layer is a TPU film, including TPU particles, an ultraviolet absorber, and an antioxidant; the middle layer is a matte PE film, including low-density polyethylene, linear low-density polyethylene, metallocene polyethylene, a composite additive, polyphthalamide, a dispersant, and an antioxidant; the inner layer is a milky white PE film, including low-density polyethylene, high-density polyethylene, and titanium dioxide. Although this stretched film improves its processing performance, wear resistance, and puncture resistance while maintaining the good mechanical properties of the PE film through the synergistic effect of modified talc powder and polytetrafluoroethylene micropowder; it can only be made into a film through a stretching process, and the mechanical properties such as the strength of the stretched film cannot meet the requirements of the liquid bag. Moreover, adhesive bonding is required between adjacent layers, complicating the preparation process and greatly reducing the production efficiency. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a blown wear-resistant packaging film for a containerized liquid bag, a preparation method thereof, and a containerized liquid bag, which can be blown into a film and greatly improve its wear resistance on the premise of meeting the high mechanical property requirements of the liquid bag.

[0005] To solve the above technical problem, the technical solution of the present invention is: design a blown wear-resistant packaging film for a containerized liquid bag, including a film body, and the film body is sequentially composed of an outer layer, a middle layer, and an inner layer from outside to inside; characterized in that: The outer layer is made of the following raw materials in parts by mass: Blow - molding grade TPU: 8 - 10 parts Slip agent: 0.5 - 1.5 parts The middle layer is made of the following raw materials in parts by mass: The first metallocene linear low - density polyethylene: 8.5 - 10.5 parts PPA: 0.3 - 0.7 parts The inner layer is made of the following raw materials in parts by mass: The second metallocene linear low - density polyethylene: 5 - 7 parts The first low - density polyethylene: 1 - 2 parts PPA: 0.3 - 0.7 parts Anti - blocking agent: 0.5 - 1.5 parts Slip agent: 0.5 - 1.5 parts The melting temperature of the blow - molding grade TPU is 170 - 240 °C. The grade of the first metallocene linear low - density polyethylene is XP8784ML. The second metallocene linear low - density polyethylene has lateral first long branches, and the first low - density polyethylene has lateral second long branches.

[0006] Preferably, the carrier of the anti - blocking agent is the second low - density polyethylene and the active ingredient is synthetic spherical silica. The carrier of the slip agent is linear low - density polyethylene with a melt index of 2 and the active ingredient is erucamide.

[0007] Preferably, both the first long branches and the second long branches are branches with more than 3 carbon atoms.

[0008] Preferably, the thickness of the film body is 110 - 120 μm.

[0009] Preferably, the thickness ratio of the outer layer, the middle layer and the inner layer is 1:2:1.

[0010] The present invention also provides a preparation method of a blow - molded wear - resistant packaging film for a bulk liquid bag, which is characterized by comprising the following steps: (1) Prepare the first special material: Mix 8 - 10 parts by mass of blow - molding grade TPU with 0.5 - 1.5 parts by mass of slip agent to obtain a first mixture; the melting temperature of the blow - molding grade TPU is 170 - 240 °C; (2) Prepare the second special material: Mix 8.5 - 10.5 parts by mass of the first metallocene linear low - density polyethylene with 0.3 - 0.7 parts by mass of PPA to obtain a second mixture; the grade of the first metallocene linear low - density polyethylene is XP8784ML; (3)Preparation of the third special material: Mix 5-7 parts by mass of the second metallocene linear low-density polyethylene, 1-2 parts by mass of the first low-density polyethylene, 0.3-0.7 parts by mass of PPA, 0.5-1.5 parts by mass of an antiblocking agent, and 0.5-1.5 parts by mass of a slip agent to obtain a third mixture; the second metallocene linear low-density polyethylene has a lateral first long branched chain, and the first low-density polyethylene has a lateral second long branched chain; (4)Film making: Coextrusion blow molding is carried out on the first mixture obtained in step (1), the second mixture obtained in step (2), and the third mixture obtained in step (3) to form an outer layer, an intermediate layer, and an inner layer arranged in sequence from outside to inside of the packaging film.

[0011] Preferably, the carrier of the antiblocking agent is the second low-density polyethylene, and the active ingredient is synthetic spherical silica; the carrier of the slip agent is linear low-density polyethylene with a melt index of 2, and the active ingredient is erucic acid amide.

[0012] Preferably, the first mixture in step (1), the second mixture in step (2), and the third mixture in step (3) are all granulated and then enter step (4).

[0013] Preferably, in step (4), the extrusion temperature of the outer layer is 185-195 °C, the extrusion temperature of the intermediate layer is 180-185 °C, and the extrusion temperature of the inner layer is 180-190 °C.

[0014] Preferably, the particle size of the spherical silica is 5-8 μm.

[0015] Preferably, the grade of the first low-density polyethylene is the same as that of the second low-density polyethylene.

[0016] Preferably, the grade of the blow molding grade TPU is 1195A.

[0017] Preferably, the grade of the second metallocene linear low-density polyethylene is 2005.

[0018] Preferably, the grade of the first low-density polyethylene is 105BR.

[0019] The present invention also provides a bulk liquid bag, including a bag body, the bag body is heat-sealed by a polyethylene film, and is characterized in that: the polyethylene film is the blow-molded wear-resistant packaging film for the above-mentioned bulk liquid bag or the packaging film prepared by the preparation method of the blow-molded wear-resistant packaging film for the above-mentioned bulk liquid bag.

[0020] Compared with the prior art, the beneficial effects of the present invention are: 1. The layers of the present invention and their raw material ratios not only enhance the abrasion resistance and rub resistance of the packaging film, increase the plasticization during film formation, but also enhance the compatibility between layers, improve the overall performance of the film body, meet the higher mechanical property requirements of the liquid bag for the packaging film, thereby blowing a wear-resistant packaging film that can be used for containerized liquid bags, and improve the heat-sealing strength of the packaging film, which is beneficial to obtaining a containerized liquid bag with high overall strength.

[0021] 2. The present invention can enhance the mixing uniformity between raw materials through granulation, laying a foundation for obtaining a packaging film with balanced performance.

[0022] 3. Through specific anti-blocking agents and slip agents, the present invention can not only improve the smoothness of the film surface, but also reduce exudation, which is beneficial to maintaining the long-term performance and reducing the pollution of the exudates to the packaged goods.

[0023] 4. The present invention has a unique concept. By improving the raw material formula and improving the plasticization of the raw materials, a packaging film with excellent mechanical properties, wear resistance and rub resistance can be blown, improving the reliability of liquid transportation in containers and facilitating popularization and application in the industry. Detailed Embodiments

[0024] The present invention will be further described in detail below in conjunction with the specific embodiments.

[0025] When referring to the present invention in the use state, the side close to the packaged goods is defined as the inner side, and correspondingly, the other side far from the packaged goods is defined as the outer side. Example 1

[0026] A wear-resistant packaging film for containerized liquid bags is prepared through the following steps: (1) Prepare the first special material: Mix 8 parts by mass of blow-molding grade TPU with 0.5 parts by mass of slip agent to obtain a first mixture, and granulate the first mixture to obtain the first special material; the blow-molding grade TPU used can specifically be TPU with the brand 1195A of BASF Company in Germany, or other brands of TPU with a melting temperature of 170 - 240 °C. TPU is a thermoplastic elastomer, which is a plastic material that can be repeatedly softened at a certain heat.

[0027] (2) Prepare the second special material: Mix 8.5 parts by mass of the first metallocene linear low-density polyethylene with 0.3 parts by mass of PPA to obtain a second mixture, and granulate the second mixture to obtain the second special material. The first metallocene linear low-density polyethylene uses MLLDPE with the brand XP8784ML of ExxonMobil Corporation in the United States.

[0028] (3) Preparation of the third special material: Mix 5 parts by mass of the second metallocene linear low-density polyethylene, 1 part by mass of the first low-density polyethylene, 0.3 part by mass of PPA, 0.5 part by mass of an antiblocking agent, and 0.5 part by mass of a slip agent to obtain a third mixture. The third mixture is pelletized to obtain the third special material. The second metallocene linear low-density polyethylene has a lateral first long-chain branch, and the first low-density polyethylene has a lateral second long-chain branch. Both the first long-chain branch and the second long-chain branch are branches containing more than 3 carbon atoms, such as isobutene, etc. The combination of the second metallocene linear low-density polyethylene and the first low-density polyethylene can not only enhance the mechanical properties of the film body but also improve the heat-sealing strength of the film body, thereby enhancing the overall strength of the bag body obtained by heat-sealing. Specifically, the second metallocene linear low-density polyethylene can be MLLDPE with the trade name 2005 of ExxonMobil Corporation in the United States, and the first low-density polyethylene can be LDPE with the trade name 105BR of ExxonMobil Corporation in the United States. The carrier of the used antiblocking agent is the second low-density polyethylene, and the active ingredient is synthetic spherical silica. The particle size of the spherical silica is 5 μm. The trade name of the second low-density polyethylene can be the same as or different from that of the first low-density polyethylene, and there is no obvious difference in their application effects. The carrier of the used slip agent is linear low-density polyethylene with a melt index of 2, and the active ingredient is erucamide.

[0029] (4) Film making: Co-extrusion blow molding is performed on the first special material obtained in step (1), the second special material obtained in step (2), and the third special material obtained in step (3) to form an outer layer, a middle layer, and an inner layer arranged in sequence from outside to inside of the packaging film. The extrusion temperature of the outer layer is 185 °C, the extrusion temperature of the middle layer is 180 °C, and the extrusion temperature of the inner layer is 180 °C. In this way, a wear-resistant packaging film with a thickness of 110 - 120 μm is obtained, and the thickness ratio of the outer layer, the middle layer, and the inner layer is 1:2:1.

[0030] The above PPA is a processing aid, which can enhance the plasticization of the raw materials, make them suitable for the blow molding process, and can eliminate shark skin and water patterns caused by melt fracture, etc., reduce crystal points caused by equipment and raw material factors, and improve the lightness and flatness of the film surface. The processing aid with the trade name PEA-3S of Huayi-Weiba Packaging Aids Co., Ltd. can be selected. Example Two

[0031] The difference between this example and Example One lies in: In step (1), the first mixture is obtained by mixing 9 parts by mass of blow molding grade TPU and 1 part by mass of a slip agent.

[0032] In step (2), the second mixture is obtained by mixing 9.5 parts by mass of the first metallocene linear low-density polyethylene and 0.5 part by mass of PPA.

[0033] In step (3), the third mixture is obtained by mixing 6 parts by mass of the second metallocene linear low-density polyethylene, 1.5 parts by mass of the first low-density polyethylene, 0.5 part by mass of PPA, 1 part by mass of an antiblocking agent, and 1 part by mass of a slip agent. The particle size of the spherical silica is 6.5 μm.

[0034] In step (4), the extrusion temperature of the outer layer is 190 °C, the extrusion temperature of the middle layer is 183 °C, and the extrusion temperature of the inner layer is 185 °C. A wear-resistant packaging film with a thickness of 115 μm is prepared.

[0035] The rest are the same as in Example 1. Example 3

[0036] The difference between this example and Example 1 is as follows: In step (1), the first mixture is obtained by mixing 10 parts by mass of blow molding grade TPU and 1.5 parts by mass of a slip agent.

[0037] In step (2), the second mixture is obtained by mixing 10.5 parts by mass of the first metallocene linear low-density polyethylene and 0.7 part by mass of PPA.

[0038] In step (3), the third mixture is obtained by mixing 7 parts by mass of the second metallocene linear low-density polyethylene, 2 parts by mass of the first low-density polyethylene, 0.7 part by mass of PPA, 1.5 parts by mass of an antiblocking agent, and 1.5 parts by mass of a slip agent. The particle size of the spherical silica is 8 μm.

[0039] In step (4), the extrusion temperature of the outer layer is 195 °C, the extrusion temperature of the middle layer is 185 °C, and the extrusion temperature of the inner layer is 190 °C. A wear-resistant packaging film with a thickness of 120 μm is prepared.

[0040] The rest are the same as in Example 1. Example 4

[0041] The difference between this example and Example 1 is as follows: In step (1), the first mixture is obtained by mixing 8 parts by mass of blow molding grade TPU and 1.5 parts by mass of a slip agent.

[0042] In step (2), the second mixture is obtained by mixing 8.5 parts by mass of the first metallocene linear low-density polyethylene and 0.7 part by mass of PPA.

[0043] In step (3), the third mixture is obtained by mixing 5 parts by mass of the second metallocene linear low-density polyethylene, 2 parts by mass of the first low-density polyethylene, 0.7 part by mass of PPA, 0.5 part by mass of an antiblocking agent, and 0.5 part by mass of a slip agent. The particle size of the spherical silica is 6 μm.

[0044] In step (4), the extrusion temperature of the outer layer is 187°C, the extrusion temperature of the middle layer is 184°C, and the extrusion temperature of the inner layer is 182°C. A wear-resistant packaging film with a thickness of 112 μm is obtained.

[0045] The rest are the same as in Example 1. Example 5

[0046] The difference between this example and Example 1 is as follows: In step (1), the first mixture is obtained by mixing 10 parts by mass of blow molding grade TPU and 0.5 part by mass of slip agent.

[0047] In step (2), the second mixture is obtained by mixing 10.5 parts by mass of the first metallocene linear low density polyethylene and 0.3 part by mass of PPA.

[0048] In step (3), the third mixture is obtained by mixing 7 parts by mass of the second metallocene linear low density polyethylene, 1 part by mass of the first low density polyethylene, 0.3 part by mass of PPA, 1.5 parts by mass of antiblocking agent and 1.5 parts by mass of slip agent. The particle size of the spherical silica is 7 μm.

[0049] In step (4), the extrusion temperature of the outer layer is 192°C, the extrusion temperature of the middle layer is 182°C, and the extrusion temperature of the inner layer is 188°C. A wear-resistant packaging film with a thickness of 118 μm is obtained.

[0050] The rest are the same as in Example 1.

[0051] Comparative Example A packaging film is obtained through the following steps: (1) Prepare a special material: It is obtained by mixing 5 parts by mass of metallocene linear low density polyethylene, 1 part by mass of low density polyethylene and 0.5 part by mass of slip agent, and the special material is obtained through pelletizing. The metallocene linear low density polyethylene used is MLLDPE with the trade name 1018MA of ExxonMobil Corporation in the United States, and the low density polyethylene is LDPE with the trade name 2426H of Daqing Petrochemical.

[0052] (2) Film making: Divide the special material prepared in step (1) into three parts, put them into three bins of a multi-layer co-extrusion machine, and through co-extrusion blowing, a packaging film with an outer layer, a middle layer and an inner layer arranged in sequence from outside to inside is obtained. The extrusion temperatures of the outer layer, the middle layer and the inner layer are 180°C. In this way, a wear-resistant packaging film with a thickness of 120 μm is obtained, and the thickness ratio of the outer layer, the middle layer and the inner layer is 1:2:1.

[0053] The packaging films prepared in the above embodiments were tested for their performance in terms of tensile strength, tear strength, elongation, puncture resistance, dart impact, heat seal strength, resistance to rubbing times, and abrasion loss, etc., and were compared with the packaging films prepared in the comparative examples. Among them, the tensile strength test was carried out in accordance with the ASTM standard "D 882-02 Test Method for Tensile Properties of Plastic Sheeting", the tear strength test was carried out in accordance with the ASTM standard "D 1004-13 American Society for Testing and Materials Standard", the puncture resistance test was carried out in accordance with the national standard "GB / T37841-2019 Test Method for Puncture Resistance of Plastic Films and Sheets", the flat dart impact test was carried out in accordance with the national standard "GB / T9639.1-2008 Plastic Films and Sheets - Test Method for Resistance to Impact - Free-Falling Dart Method - Part 1: Staircase Method", the heat seal strength was carried out in accordance with the industry standard "QB / T2358-1998 Test Method for Heat Seal Strength of Plastic Film Packaging Bags", the resistance to rubbing times was carried out in accordance with the industry standard "QB / T 5787-2022 Test Method for Rubbing Resistance of Plastic Films", and the abrasion loss was carried out in accordance with the national standard "GBT 40797-2021 Determination of Abrasion Resistance of Vulcanized Rubber or Thermoplastic Rubber - Vertical Driving Abrasive Disc Method". The test results are as follows:

[0054] It can be seen that compared with the comparative example, the packaging film prepared by the present invention has improved tensile strength, tear strength, puncture resistance, elongation, dart impact, and heat seal strength on the premise of the same thickness, number of layers set, and thickness of each layer, and can meet the mechanical property requirements of the container bag for liquid, especially in terms of the resistance to rubbing times and abrasion loss, which can better serve the actual transportation of liquid.

[0055] The prepared packaging film can also be heat-sealed into a container bag for liquid, which is convenient for packaging and use.

[0056] The raw material composition expressed in a closed form in the present invention refers to the main raw materials, that is, the raw materials with a percentage occupancy of more than 99.5% in the total mass of the raw materials, and may also include other trace auxiliary materials. That is to say, on the basis of the raw material composition expressed in a closed form in the present invention, if the proportion of the added auxiliary materials in the total mass of the raw materials does not exceed 0.5%, it still belongs to the protection scope of the present invention.

[0057] The above are only the preferred embodiments of the present invention, and are not limitations to the present invention in other forms. Any person skilled in the art may use the technical content disclosed above to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still belong to the protection scope of the technical solution of the present invention.

Claims

1. A blown wear-resistant packaging film for a containerized liquid bag, comprising a film body, and the film body is composed of an outer layer, an intermediate layer and an inner layer in sequence from outside to inside; characterized in that: The outer layer is made of the following raw materials by mass: Blow molding grade TPU 8 - 10 parts Slip agent 0.5 - 1.5 parts The intermediate layer is made of the following raw materials by mass: First metallocene linear low density polyethylene 8.5 - 10.5 parts PPA 0.3 - 0.7 parts The inner layer is made of the following raw materials by mass: Second metallocene linear low density polyethylene 5 - 7 parts First low density polyethylene 1 - 2 parts PPA 0.3 - 0.7 parts Antiblocking agent 0.5 - 1.5 parts Slip agent 0.5 - 1.5 parts The melting temperature of the blow molding grade TPU is 170 - 240 °C, the grade of the first metallocene linear low density polyethylene is XP8784ML, the second metallocene linear low density polyethylene has a lateral first long branch chain, and the first low density polyethylene has a lateral second long branch chain.

2. The blow-molded wear-resistant packaging film for containerized liquid bags according to claim 1, wherein: The carrier of the antiblocking agent is second low density polyethylene, and the active ingredient is synthetic spherical silica; the carrier of the slip agent is linear low density polyethylene with a melt index of 2, and the active ingredient is erucamide.

3. The blow-molded wear-resistant packaging film for the bulk liquid bag according to claim 2, wherein: Both the first long branch chain and the second long branch chain are branches with more than 3 carbons.

4. The blow-molded wear-resistant packaging film for containerized liquid bags according to any one of claims 1 to 3, characterized in that: The thickness of the film body is 110 - 120 μm.

5. The blow-molded wear-resistant packaging film for containerized liquid bags according to claim 4, wherein: The thickness ratio of the outer layer, the intermediate layer and the inner layer is 1:2:

1.

6. A preparation method of a blown wear-resistant packaging film for a bulk liquid bag, characterized in that: It includes the following steps: (1) Prepare the first special material: Mix 8 - 10 parts by mass of blow molding grade TPU with 0.5 - 1.5 parts by mass of slip agent to obtain the first mixture; the melting temperature of the blow molding grade TPU is 170 - 240 °C; (2) Prepare the second special material: Mix 8.5 - 10.5 parts by mass of the first metallocene linear low density polyethylene with 0.3 - 0.7 parts by mass of PPA to obtain the second mixture; the grade of the first metallocene linear low density polyethylene is XP8784ML; (3) Prepare the third special material: Mix 5 - 7 parts by mass of the second metallocene linear low density polyethylene, 1 - 2 parts by mass of the first low density polyethylene, 0.3 - 0.7 parts by mass of PPA, 0.5 - 1.5 parts by mass of antiblocking agent and 0.5 - 1.5 parts by mass of slip agent to obtain the third mixture; the second metallocene linear low density polyethylene has a lateral first long branch chain, and the first low density polyethylene has a lateral second long branch chain; (4) Film making: Co - extrude and blow the first mixture obtained in step (1), the second mixture obtained in step (2) and the third mixture obtained in step (3) to form an outer layer, an intermediate layer and an inner layer arranged in sequence from outside to inside of the packaging film.

7. The preparation method of the blow-molded wear-resistant packaging film for the containerized liquid bag according to claim 6, characterized in that: The carrier of the antiblocking agent is second low density polyethylene, and the active ingredient is synthetic spherical silica; the carrier of the slip agent is linear low density polyethylene with a melt index of 2, and the active ingredient is erucamide.

8. The preparation method of the blow-molded wear-resistant packaging film for the containerized liquid bag according to claim 6 or 7, characterized in that: The first mixture in step (1), the second mixture in step (2) and the third mixture in step (3) all enter step (4) after pelletizing.

9. The preparation method of the blow-molded wear-resistant packaging film for the containerized liquid bag according to claim 8, characterized in that: In step (4), the extrusion temperature of the outer layer is 185 to 195 °C, the extrusion temperature of the middle layer is 180 to 185 °C, and the extrusion temperature of the inner layer is 180 to 190 °C.

10. A bulk liquid bag, comprising a bag body, wherein the bag body is formed by heat-sealing a polyethylene film, and is characterized in that: The polyethylene film is a packaging film prepared by the preparation method of the blown wear-resistant packaging film for containerized liquid bags according to any one of claims 1 to 5 or the blown wear-resistant packaging film for containerized liquid bags according to any one of claims 6 to 9.

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