Pouch container

Abstract

To suppress long-term deterioration of an inner layer including polyethylene.SOLUTION: A pouch container holds a content liquid containing hydrogen peroxide. The pouch container includes, in an inner layer, polyethylene in which a ratio B / A of complex viscosity A of 10 rad / s and complex viscosity B of 0.1 rad / s measured by a dynamic viscosity measurement at a measured temperature of 180°C is equal to or less than 2.5.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a pouch container. [Background technology]

[0002] Pouch containers such as stand-up pouches are used as refill containers for toiletries such as liquid detergent, bleach, fabric softener, shampoo, etc. Such pouch containers are made of a laminated film containing polyethylene in the inner layer, which has excellent sealing properties by heat compression bonding (see Patent Document 1 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-178348 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, pouch containers have been increasingly adopted as refill containers for various products in order to reduce the amount of synthetic resin used.

[0005] However, when the pouch container holds a liquid content containing hydrogen peroxide, the inner layer of the pouch container can be damaged by active oxygen generated from the hydrogen peroxide, and can deteriorate over time.

[0006] In particular, when products are stored for long periods due to stockpiling by consumers or when products are stored for long periods in stores, it is desirable to suppress deterioration of the inner layer over time in order to prevent the pouch container from breaking.

[0007] The present invention relates to a technique capable of suppressing deterioration over time of an inner layer containing polyethylene in a pouch container that holds a content liquid containing hydrogen peroxide. [Means for solving the problem]

[0008] In order to solve the above problems, one aspect of the present invention relates to a pouch container for holding a content liquid containing hydrogen peroxide, the pouch container comprising an inner layer of polyethylene having a ratio B / A of 2.5 or less, where A is a complex viscosity of 10 rad / s and B is a complex viscosity of 0.1 rad / s, as measured by dynamic viscoelasticity measurement at a measurement temperature of 180°C. Effect of the Invention

[0009] As described above, according to the present invention, it is possible to suppress deterioration over time of the inner layer of a pouch container that holds a content liquid containing hydrogen peroxide. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram illustrating a pouch container according to one embodiment of the present invention. [Diagram 2] FIG. 2 is an explanatory diagram illustrating a laminated structure of a laminated film that constitutes the pouch container shown in FIG. [Diagram 3] FIG. 1 is a graph showing typical results of dynamic viscoelasticity measurement of a linear polymer. [Figure 4] FIG. 2 is a graph showing the measurement results of the storage modulus G′ and loss modulus G″ of the polyethylene according to Example 1. [Diagram 5] FIG. 4 is a graph showing the measurement results of the storage modulus G′ and loss modulus G″ of the polyethylene of Example 2. [Figure 6] FIG. 2 is a graph showing the measurement results of the storage modulus G′ and loss modulus G″ of the polyethylene according to Comparative Example 1. [Figure 7] FIG. 2 is a graph showing the measurement results of complex viscosity η* of polyethylenes according to Examples 1 and 2 and Comparative Example 1. [Figure 8] FIG. 1 is a graph showing a calibration curve of polystyrene used for calibration of GPC. [Figure 9] FIG. 4 is a graph showing the measurement results of the molecular weight distribution of the polyethylene according to Example 2. [Figure 10]FIG. 2 is a graph showing the measurement results of the molecular weight distribution of the polyethylene according to Comparative Example 1. [Figure 11] FIG. 2 is an explanatory diagram showing the shape punched into a polyethylene sheet in strength measurement. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and the drawings, components having substantially the same functional configurations are designated by the same reference numerals, and duplicated explanations will be omitted.

[0012] <Pouch container> First, a pouch container to which an embodiment of the present invention is applied will be described with reference to Figures 1 and 2. Figure 1 is an explanatory diagram that shows a schematic view of a pouch container 1 according to one embodiment of the present invention.

[0013] As shown in Fig. 1, the pouch container 1 according to this embodiment is a standing pouch having a laminate film 10 as a body member and a bottom member. The pouch container 1 is constructed by bonding a plurality of laminate films 10 together at a seal portion 2. For example, the pouch container 1 may be constructed by bonding a body member made of two sheets of laminate films 10 and a bottom member made of laminate films 10 bent inwardly into a V-shape together at a side seal portion 2A and a bottom seal portion 2B by thermocompression bonding.

[0014] The pouch container 1 is also provided with a spout 3 which is a spout for discharging the liquid content held in the pouch container 1 to the outside. The spout 3 is closed by attaching a screw plug 4. It is noted that the spout 3 does not necessarily have to be provided on the pouch container 1.

[0015] The pouch container 1 is filled with a content liquid containing hydrogen peroxide. The concentration of hydrogen peroxide in the content liquid held in the pouch container 1 may be, for example, 1% by mass or more and 5% by mass or less. The content liquid held in the pouch container 1 is, for example, a bleaching agent.

[0016] The volume of the content liquid held in the pouch container 1 is not particularly limited, but may be more than 1200 mL, preferably more than 1500 mL, more preferably more than 1800 mL, and even more preferably more than 2000 mL, from the viewpoint of container efficiency. That is, the pouch container 1 may be a large pouch container capable of holding multiple refills of the content liquid, which exceeds the amount of one refill (e.g., 500 mL to 1000 mL). The upper limit of the volume of the content liquid held in the pouch container 1 is not particularly limited, but may be, for example, 3500 mL.

[0017] The pouch container 1 according to this embodiment is composed of a laminated film 10 having a structure shown in Fig. 2. Fig. 2 is an explanatory diagram that illustrates a typical laminated structure of the laminated film 10 that constitutes the pouch container 1 shown in Fig. 1.

[0018] As shown in FIG. 2, the laminated film 10 is a laminated film in which an inner layer 11 containing polyethylene and an outer layer 12 serving as a base material are laminated together.

[0019] The inner layer 11 is a layer on the inner surface side that comes into contact with the content liquid of the pouch container 1. The inner layer 11 contains polyethylene to improve the sealing property by thermocompression bonding. Specifically, the inner layer 11 contains polyethylene having properties described later to suppress deterioration of the inner layer 11 over time due to hydrogen peroxide contained in the content liquid held inside the pouch container 1. The thickness of the inner layer 11 may be, for example, 50 μm to 250 μm.

[0020] The outer layer 12 is a layer on the outer surface side of the pouch container 1. The outer layer 12 is made of a material having impact resistance to protect the pouch container 1 from physical impact to the pouch container 1. For example, the outer layer 12 may be made including polypropylene, polyethylene terephthalate (PET), or nylon. Preferably, the outer layer 12 may be made including uniaxially oriented polypropylene, biaxially oriented PET, or biaxially oriented nylon. The thickness of the outer layer 12 may be, for example, 3 μm to 50 μm.

[0021] The outer layer 12 may also have a laminated structure of multiple layers. Specifically, the outer layer 12 may have a laminated structure of multiple layers including PET or nylon. For example, the outer layer 12 may have a two-layer structure of a PET layer and a nylon layer laminated from the outside, or a three-layer structure of a PET layer, a PET layer, and a nylon layer laminated from the outside.

[0022] <Background> In recent years, in order to reduce the amount of synthetic resins and the like used, studies have been conducted on pouch containers 1 for refilling toiletry products, in which the containers are enlarged to hold a volume of content liquid that allows multiple refills.

[0023] However, since the enlarged pouch container 1 is stored for a longer period of time while retaining the liquid content, compared to a pouch container with a capacity for one refill, damage to the inner layer 11 caused by hydrogen peroxide contained in the liquid content may become apparent. Specifically, damage to the inner layer 11 of the pouch container 1 by active oxygen generated from hydrogen peroxide may cause the pouch container 1 to break or the inner layer 11 to crack over time. Even in the case of a pouch container with a capacity for one refill, there is a possibility that the pouch container 1 may break and the inner layer 11 may crack due to deterioration over time due to long-term storage caused by consumers hoarding or long-term storage in store inventory.

[0024] In particular, in the case of a large pouch container 1, the load of the liquid contents on the pouch container is large, and there is a possibility that a large amount of the liquid contents will leak out when the pouch is broken, so it is more desirable to suppress deterioration over time of the inner layer 11 of the pouch container 1.

[0025] This embodiment was created with the above circumstances in mind. The pouch container 1 according to this embodiment includes an inner layer 11 made of polyethylene having a structure that is less likely to be decomposed by active oxygen generated from hydrogen peroxide. This makes it possible for the pouch container 1 to further suppress deterioration of the inner layer 11 over time. The polyethylene contained in the inner layer 11 of the pouch container 1 according to this embodiment will be described below.

[0026] In addition to polyethylene, a resin other than polyethylene may be blended into the inner layer 11. Even in such a case, the present invention can similarly suppress deterioration over time of the inner layer 11 of the pouch container 1.

[0027] <Polyethylene> (Features) As described above, in order to suppress deterioration over time of the inner layer 11 of the pouch container 1 that holds the content liquid including hydrogen peroxide, it is important to construct the inner layer 11 from polyethylene, which has a structure that is less susceptible to decomposition by the active oxygen generated from hydrogen peroxide.

[0028] If we consider the bond strength of the chemical bonds in the hydrocarbon chain that is the main structure of polyethylene, the bond dissociation energy of hydrogen bonded to carbon decreases as the carbon substitution number of carbon increases. Therefore, tertiary carbon is more likely to be radicalized than secondary carbon, which has a lower carbon substitution number, and therefore may be more easily radicalized and decomposed by the attack of active oxygen, etc.

[0029] Since such tertiary carbons exist at the branching points of the hydrocarbon chains of polyethylene, it is believed that the more branches a polyethylene has, the more susceptible the tertiary carbons at the branching points are to be attacked by active oxygen, and the more susceptible it is to deterioration over time. Therefore, it is believed that linear polyethylene with fewer branches and fewer tertiary carbons at the branching points is more resistant to attack by active oxygen and suppresses deterioration over time.

[0030] An example of a property indicating the linear or branched structure of a polymer such as polyethylene is viscoelasticity. Viscoelasticity is a combination of elasticity, which stores deformation energy like a spring, and viscosity, which dissipates deformation energy internally, and is a property that is prominent in polymer melts.

[0031] Specifically, polymer melts have a larger free volume than solids, and therefore the cohesive force between polymers is weak. Therefore, polymer melts consume applied external forces as thermal energy for the movement (flow) of the object, and also store it as internal energy (elastic energy) through the entanglement between the polymers. This allows polymer melts to exhibit viscoelastic properties that have viscosity due to the flow of the polymers and elasticity due to the entanglement between the polymers. The movement and entanglement of each polymer in a polymer melt are affected by the molecular weight and branching structure of the polymer, so by measuring the viscoelastic properties of the polymer melt, it is possible to evaluate the amount of branching structure of the polymer.

[0032] Viscoelastic properties are measured, for example, by periodically applying deformation (strain) to a sample (polymer melt) and detecting the stress and phase difference caused by the deformation. Such measurement of viscoelastic properties is also called dynamic viscoelasticity measurement. Dynamic viscoelasticity can be measured, for example, using a rheometer. The storage modulus (elastic term), loss modulus (viscous term), and complex viscosity (viscosity term) of a sample can be determined by dynamic viscoelasticity measurement.

[0033] Here, the angular frequency dependence of the complex viscosity of a melt of a linear polymer is shown in Fig. 3. Fig. 3 is a graph showing typical results of dynamic viscoelasticity measurement (angular frequency dependence) of a linear polymer.

[0034] The angular frequency on the horizontal axis of the graph shown in Figure 3 is the frequency of the deformation periodically applied to the sample, and corresponds to the relaxation time in the elasticity of the object, and corresponds to the flow speed in the viscosity of the object. As shown in Figure 3, in a polymer melt, the complex viscosity increases as the angular frequency decreases.

[0035] However, in the melt of a linear polymer, slippage between polymers is likely to occur and the fluidity is high, so the complex viscosity forms a plateau region FA where the rate of increase is extremely small in the region of low angular frequency, and finally becomes a constant value. This is because in the region of sufficiently long relaxation time, the melt of a linear polymer with high fluidity behaves as a viscous body with a constant viscosity (zero shear viscosity). On the other hand, in a polymer with many branched structures, the branched structures are entangled with each other, so slippage between polymers is unlikely to occur and the fluidity is low. For this reason, in the melt of a polymer with many branched structures, the complex viscosity does not form a plateau region FA in the region of low angular frequency, and instead increases monotonically as the angular frequency decreases.

[0036] Therefore, the amount of branched structure of a polymer melt can be determined by determining whether or not a plateau region FA is formed on the low angular frequency side of the complex viscosity measured by dynamic viscoelasticity measurement.

[0037] As an example, the flat region FA of the complex viscosity can be defined by the ratio of the complex viscosities at two points on the low angular frequency side being equal to or less than a threshold value. Specifically, the polyethylene contained in the inner layer 11 of the pouch container 1 according to this embodiment may have a ratio B / A of 2.5 or less between the complex viscosity A of 10 rad / s and the complex viscosity B of 0.1 rad / s measured by dynamic viscoelasticity measurement at a measurement temperature of 180°C. The lower limit of the ratio B / A is not particularly limited, but for example, the ratio B / A may be 1 or more. When the ratio B / A is 1, the complex viscosity graph becomes completely flat in the range of 0.1 rad / s to 10 rad / s.

[0038] As another example, the flat region FA of the complex viscosity can be defined by the difference between the complex viscosities at two points on the low angular frequency side being equal to or less than a threshold value. Specifically, the polyethylene contained in the inner layer 11 of the pouch container 1 according to this embodiment may have a difference BA between a complex viscosity A of 10 rad / s and a complex viscosity B of 0.1 rad / s measured by dynamic viscoelasticity measurement at a measurement temperature of 180°C, which may be equal to or less than 5000 Pa·s. The lower limit of the difference BA is not particularly limited, but may be, for example, 0 Pa·s or more. When the difference BA is 0 Pa·s, the complex viscosity graph becomes completely flat in the range of 0.1 rad / s to 10 rad / s.

[0039] When the polyethylene contained in the inner layer 11 satisfies the above characteristics, the branched structure contained in the polyethylene structure is sufficiently small. Therefore, as shown in the examples described later, the pouch container 1 can suppress deterioration of the inner layer 11 over time caused by active oxygen generated from hydrogen peroxide.

[0040] The breaking strain of the polyethylene contained in the inner layer 11 of the pouch container 1 may be 400% or more. The upper limit of the breaking strain of the polyethylene is not particularly limited, but for example, the breaking strain of the polyethylene may be 1000% or less.

[0041] When the polyethylene contained in the inner layer 11 satisfies the above characteristics, the pouch container 1 can further increase the strength of the inner layer 11. Therefore, as shown in the examples described later, the pouch container 1 can further suppress breakage of the pouch container 1 and cracks in the inner layer 11. The breaking strain of the polyethylene can be measured, for example, by a tensile strength tester.

[0042] Furthermore, the molecular weight distribution Mw / Mn of the polyethylene contained in the inner layer 11 of the pouch container 1 may be 9 or less. There is no particular lower limit to the molecular weight distribution Mw / Mn of the polyethylene, but, for example, the molecular weight distribution Mw / Mn may be 1 or more. When the molecular weight distribution Mw / Mn is 1, the polyethylene is composed of a polymer of a single molecular weight.

[0043] When the polyethylene contained in the inner layer 11 satisfies the above characteristics, the polyethylene has a narrower molecular weight distribution and higher polymer uniformity, so that it is expected that the strength will be stable and the proportion of low molecular weight polyethylene, which is prone to deterioration, will be lower. Therefore, the strength of the inner layer 11 of the pouch container 1 can be increased, and as shown in the examples described below, breakage of the pouch container 1 and cracks in the inner layer 11 can be further suppressed. The molecular weight distribution Mw / Mn of the polyethylene can be measured, for example, by gel permeation chromatography (GPC).

[0044] (Synthesis method) Linear polyethylene with less branching can be synthesized by various methods. For example, linear polyethylene with less branching can be synthesized by coordination ion polymerization using a transition metal catalyst. The transition metal catalyst is, for example, a Ziegler-Natta catalyst or a metallocene catalyst. In particular, linear polyethylene with less branching can be synthesized by using a metallocene catalyst.

[0045] Furthermore, by using the above-mentioned transition metal catalyst and copolymerizing ethylene and an α-olefin (propylene, butene, or pentene) under various conditions, it is possible to synthesize polyethylene having a suitable crystallinity and melting point as a constituent material of the inner layer 11 of the pouch container 1. From the viewpoint of ensuring the sealing properties of the laminated film 10, the melting point of the polyethylene is desirably 90°C to 140°C. The crystallinity and melting point of the polyethylene can be controlled by adjusting the ethylene content in the copolymerization.

[0046] <Action and effect> According to one embodiment of the present invention described above, the pouch container 1 has an inner layer 11 made of linear polyethylene that is resistant to active oxygen generated from hydrogen peroxide water, and therefore deterioration over time when holding a content liquid containing hydrogen peroxide can be suppressed. In particular, the pouch container 1 enlarged to be able to hold more than 1200 mL of content liquid can be stored more stably for a long period of time because the inner layer 11 is made of polyethylene that is capable of suppressing deterioration over time.

[0047] In such linear polyethylene, a plateau region FA is formed on the low angular frequency side in a complex viscosity graph obtained by dynamic viscoelasticity measurement, where the rate of change is extremely small. As one example, the plateau region FA may be specified when the ratio B / A between the complex viscosity A at 10 rad / s and the complex viscosity B at 0.1 rad / s measured by dynamic viscoelasticity measurement at a measurement temperature of 180°C is 2.5 or less. As another example, the plateau region FA may be specified when the difference BA between the complex viscosity A at 10 rad / s and the complex viscosity B at 0.1 rad / s measured by dynamic viscoelasticity measurement at a measurement temperature of 180°C is 5000 Pa s or less.

[0048] The breaking strain of the polyethylene constituting the inner layer 11 of the pouch-container 1 according to this embodiment may be 400% or more. In this case, by increasing the strength of the inner layer 11, the pouch-container 1 can be more effectively prevented from breaking and cracking.

[0049] Furthermore, the molecular weight distribution Mw / Mn of the polyethylene constituting the inner layer 11 of the pouch container 1 according to this embodiment may be equal to or less than 9. In such a case, the strength of the inner layer 11 of the pouch container 1 can be further increased, and therefore breakage of the pouch container 1 and cracks in the inner layer 11 can be further suppressed. EXAMPLES

[0050] The present invention will be described in more detail below with reference to examples and comparative examples. Note that the materials, steps, and procedures shown below are merely examples, and the scope of the present invention is not limited to the examples shown below.

[0051] Example 1 A laminated film containing polyethylene in the inner layer, which was obtained by adjusting various conditions using a metallocene catalyst and copolymerizing ethylene and protein, was prepared. The layer structure of the laminated film was 150 μm of polyethylene sealant / 15 μm of nylon / 12 μm of PET from the inner layer side. Next, a spouted standing pouch with a width of 200 mm, a height of 315 mm, and a folding length of the bottom member of 60 mm was produced using the laminated film. Furthermore, 1300 mL of a content liquid containing 2% by mass of hydrogen peroxide and 5% by mass of a polyoxyethylene alkyl ether surfactant was charged into the produced standing pouch, and the upper part of the standing pouch was sealed by heat compression. In this way, a pouch container according to Example 1 was produced.

[0052] Example 2 A laminated film containing polyethylene in the inner layer, which was obtained by adjusting various conditions using a metallocene catalyst and copolymerizing ethylene and protein, was prepared. The layer structure of the laminated film was polyethylene sealant 180 μm / nylon 15 μm / PET 12 μm / PET 12 μm from the inner layer side. Next, a spouted standing pouch with a width of 255 mm, height of 340 mm, and a folding length of the bottom member of 70 mm was produced using the laminated film. Furthermore, 2000 mL of a content liquid containing 2% by mass of hydrogen peroxide and 5% by mass of a polyoxyethylene alkyl ether surfactant was charged into the produced standing pouch, and the upper part of the standing pouch was sealed by heat compression. This produced a pouch container according to Example 2.

[0053] Comparative Example 1 A laminated film containing polyethylene copolymerized with ethylene under high pressure and high temperature by adjusting various conditions was prepared. The layer structure of the laminated film was polyethylene sealant 150 μm / PET 12 μm / nylon 15 μm from the inner layer side. Next, a spouted standing pouch with a width of 160 mm, height of 270 mm, and a folding length of the bottom member of 40 mm was produced using the laminated film. Furthermore, 800 mL of a content liquid containing 2 mass% hydrogen peroxide and 5 mass% polyoxyethylene alkyl ether surfactant was charged into the produced standing pouch, and the upper part of the standing pouch was sealed by heat compression. In this way, a pouch container according to Comparative Example 1 was produced.

[0054] (Viscoelasticity measurement) The polyethylene contained in the inner layer of the pouch containers according to Examples 1 and 2 and Comparative Example 1 was extracted by the following method and prepared as a sample for viscoelasticity measurement.

[0055] Specifically, first, the pouch containers according to Examples 1 and 2 and Comparative Example 1 were cut into 5 cm squares using a cutter or the like, and then placed in a screw tube together with 100 g of a 5 mol / L aqueous sodium hydroxide solution, thereby immersing the container in the aqueous sodium hydroxide solution. The screw tube was stored in a 40°C environment for 2 weeks, and the polyethylene sealant was separated from other PET or nylon. The polyethylene sealant was then removed, washed with water, and dried. The dried polyethylene sealant was used as a sample for viscoelasticity measurement.

[0056] The viscoelasticity measurements were carried out using the following measuring instruments and conditions. Measurement equipment: Rheometer MCR702e (Anton Paar) Measurement jig: Parallel plate 20 mm, gap 0.5 mm Measurement temperature: 180℃ Measurement mode: Frequency dispersion, angular frequency 0.1rad / s~1000rad / s Measurement items: storage modulus G', loss modulus G'', complex viscosity η *

[0057] First, the inside of the chamber oven of the rheometer was heated to 180°C, and the sample prepared above was set on the measurement dish on the measurement plate. After confirming that the sample had sufficiently softened and melted, the parallel plate of the measurement jig was set on top of the sample so that the gap between the measurement dish and the parallel plate was the above-mentioned (0.5 mm). At that time, any sample spilling out from between the measurement dish and the measurement jig was removed. After confirming that the temperature inside the chamber oven and the sample had stabilized at the measurement temperature (180°C), the viscoelasticity was measured in the above-mentioned measurement mode.

[0058] The measurement results of the storage modulus G' and loss modulus G'' of the polyethylene of Example 1 are shown in FIG. 4, and the measurement results of the storage modulus G' and loss modulus G'' of the polyethylene of Example 2 are shown in FIG. 5. The measurement results of the storage modulus G' and loss modulus G'' of the polyethylene of Comparative Example 1 are shown in FIG. 6. In addition, the complex viscosities η of the polyethylenes of Examples 1 and 2 and Comparative Example 1 were * The measurement results are shown in Figure 7.

[0059] Furthermore, the complex viscosity A at 10 rad / s, the complex viscosity B at 0.1 rad / s, the complex viscosity ratio B / A, and the complex viscosity difference BA of the polyethylenes of Examples 1 and 2, and Comparative Example 1, which were calculated from the viscoelasticity measurement results, are shown in Table 1 below.

[0060] [Table 1]

[0061] (Molecular weight distribution measurement) The polyethylene contained in the inner layer of the pouch containers according to Examples 1 and 2 and Comparative Example 1 was extracted by the following method and prepared as a sample for molecular weight distribution measurement.

[0062] Specifically, first, the polyethylene sealant contained in the inner layer of the pouch container according to Examples 1 and 2 and Comparative Example 1 was taken out in the same manner as in the viscoelasticity measurement, washed with water, and then dried. Then, 20 mL of the mobile phase for GPC measurement was added to 40 mg of the dried polyethylene sealant, and the mixture was shaken at 145°C to dissolve the polyethylene sealant. Furthermore, the solution was hot-filtered with a sintered filter having a pore size of 1.0 μm, and the filtrate was used as a sample for molecular weight distribution measurement.

[0063] The molecular weight distribution was measured by high-temperature GPC using the following measuring equipment and conditions. Column: TSKgel (registered trademark) GMH6-HT x 2 + TSKgel GMH6-HTL x 2, inner diameter 7.5 mm x length 300 mm (Tosoh) Temperature: 140℃ Mobile phase: o-dichlorobenzene (containing 0.025% BHT by mass) Flow rate: 1.0mL / min Injection volume 0.4mL Detector: Differential refractometer (RI) Column calibration: Monodisperse polystyrene (TSKgel standard polystyrene: Tosoh) Molecular weight calibration: relative calibration method (polystyrene equivalent) Equipment: HLC-8321GPC / HT type high temperature gel permeation chromatograph (Tosoh) Analysis software: Empower3 (Nihon Waters)

[0064] Moreover, the polystyrene calibration curve used for the GPC calibration is shown in FIG. 8, and the polystyrene calibration curve table is shown in Table 2 below.

[0065] [Table 2]

[0066] The measurement results of the molecular weight distribution of the polyethylene according to Example 2 are shown in Figure 9, and the measurement results of the molecular weight distribution of the polyethylene according to Comparative Example 1 are shown in Figure 10. Furthermore, the weight average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (Mw / Mn), and peak top molecular weight (Mp) of the polyethylenes according to Examples 1 and 2 and Comparative Example 1, calculated from the measurement results of the molecular weight distribution, are shown in Table 3 below.

[0067] [Table 3]

[0068] (Strength measurement) The polyethylene contained in the inner layer of the pouch containers according to Examples 1 and 2 and Comparative Example 1 was taken out by the following method and prepared as a sample for strength measurement.

[0069] Specifically, first, the polyethylene sealant contained in the inner layer of the pouch container according to Examples 1 and 2 and Comparative Example 1 was taken out in the same manner as in the viscoelasticity measurement, washed with water, and then dried. The dried polyethylene sealant was then set in a hot press machine with a 180 μm spacer heated to 180° C. and pressed at 20 MPa to obtain a 180 μm thick sheet. The pressed 180 μm thick sheet was then cut into the shape shown in FIG. 11 using a punching blade to obtain a sample for strength measurement.

[0070] Fig. 11 is an explanatory diagram showing the shape punched out of the polyethylene sheet in strength measurement. The dimensions of the shape shown in Fig. 11 are as follows: l3:150mm l2:108mm l1:60mm r(radius):60mm b2:20mm b1:10mm h (thickness): 180 μm

[0071] The strength measurements were carried out using the following measuring equipment and conditions. Measuring equipment: AG-X load cell 5kN (Shimadzu Corporation) Measurement tool: Load cell with air chuck Measurement mode: Tensile strength test, tensile speed 50mm / min Measurement items: Maximum stress, breaking strain

[0072] The results of the strength measurements of the polyethylenes of Examples 1 and 2 and Comparative Example 1 are shown in Table 4 below.

[0073] [Table 4]

[0074] (Evaluation of aging) The pouch containers according to Examples 1 and 2 and Comparative Example 1 were stored in an environment of 65° C. for three months to evaluate the degree of deterioration over time. After removing the liquid contents from the pouch containers according to Examples 1 and 2 and Comparative Example 1 after storage, the state of the polyethylene sealant in the inner layer was visually observed to check for cracks, liquid leakage, peeling of the laminate, etc. The evaluation results are shown in Table 5 below.

[0075] [Table 5]

[0076] (comprehensive evaluation) The measurement results of the polyethylene according to Examples 1 and 2 and Comparative Example 1, and the evaluation results of the pouch containers are summarized in Table 6 below.

[0077] [Table 6]

[0078] As shown in Table 6 above, the polyethylenes according to Examples 1 and 2 have a ratio B / A of 2.5 or less between the complex viscosity A at 10 rad / s and the complex viscosity B at 0.1 rad / s measured by dynamic viscoelasticity measurement at a measurement temperature of 180°C, and therefore can suppress cracking, liquid leakage, and laminate peeling of the pouch container due to aging. In addition, the polyethylenes according to Examples 1 and 2 have a breaking strain of 400% or more and high strength, and therefore can suppress cracking, liquid leakage, and laminate peeling of the pouch container due to aging. In addition, the polyethylenes according to Examples 1 and 2 have a molecular weight distribution Mw / Mn of 9 or less, and therefore can suppress cracking, liquid leakage, and laminate peeling of the pouch container due to aging.

[0079] Although the preferred embodiment of the present invention has been described in detail above with reference to the accompanying drawings, the present invention is not limited to such an example. It is clear that a person having ordinary knowledge in the technical field to which the present invention pertains can conceive of various modified or altered examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally belong to the technical scope of the present invention. [Explanation of symbols]

[0080] 1 Pouch Container 2 Seal Part 2A Side seal part 2B Bottom seal part 3 Spout 4 Screw cap 10 Laminated film 11 Inner layer 12 Outer layer

Claims

1. A pouch container for holding a content liquid containing hydrogen peroxide, A pouch container comprising an inner layer of polyethylene having a ratio B / A of 2.5 or less, where A is a complex viscosity of 10 rad / s and B is a complex viscosity of 0.1 rad / s, as measured by dynamic viscoelasticity measurement at a measurement temperature of 180°C.

2. The pouch container according to claim 1, wherein the difference B-A between the complex viscosity B at 0.1 rad / s and the complex viscosity A at 10 rad / s is 5000 Pa·s or less.

3. 2. The pouch container according to claim 1, wherein the polyethylene has a breaking strain of 400% or more.

4. 2. The pouch container according to claim 1, wherein the molecular weight distribution Mw / Mn of the polyethylene is 9 or less.

5. The pouch container according to any one of claims 1 to 4, wherein the polyethylene is polyethylene polymerized by a metallocene catalyst.

6. The pouch container according to any one of claims 1 to 4, wherein the pouch container is a stand-up pouch.

7. The pouch container according to any one of claims 1 to 4, wherein the volume of the content liquid is more than 1200 mL.

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