Packaging material, and packaging bags and silicone packaging materials using the same.

Abstract

For example, in packaging bags for silicone materials such as polysilicon nuggets, the present invention provides a means to prevent damage to the packaging bag during transportation of the package containing the silicone material. [Solution] The structure comprises, in order from the outermost layer to the innermost layer, an outer layer mainly composed of a cyclic olefin resin or low-density polyethylene, a gas barrier layer mainly composed of an ethylene-vinyl alcohol copolymer, and a heat seal layer mainly composed of low-density polyethylene, with a density of 0.86 g / cm³. 3 More than 0.90g / cm 3 A multilayer film is used as a packaging material, further comprising a water vapor barrier layer between the outer layer and the heat seal layer, the water vapor barrier layer being mainly composed of a polyolefin resin having the following density.

Description

[Technical Field]

[0001] This invention relates to a packaging material, and to a packaging bag for silicone material and a packaging body for silicone material using the same. [Background technology]

[0002] Silicon materials such as polysilicon, which are raw materials for silicon wafers used in the manufacture of semiconductor products, are generally transported in the form of a packaged product enclosed in a double bag. As an example of a double packaging bag for transporting such silicon materials, Patent Document 1 discloses a double packaging bag comprising a first bag as a so-called outer bag and a second bag as a so-called inner bag placed inside the first bag, which is made of a packaging material including a laminate in which a first resin substrate layer, a barrier layer, a second resin substrate layer, and a sealant layer are laminated in this order. Patent Document 1 also discloses that the structure of the barrier layer may be a vapor-deposited film obtained by depositing an inorganic oxide such as silica or alumina onto, for example, a PET layer. Furthermore, it is disclosed that the barrier layer may be a metal vapor-deposited film obtained by depositing a metal such as aluminum onto the first resin substrate layer or the second resin substrate layer, or a metal foil such as aluminum. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-075309 [Overview of the project] [Problems that the invention aims to solve]

[0004] Here, since polysilicon nuggets are a brittle material, the edges of the cut surface and the edges of the crushed surface are often sharp. For this reason, vibrations during transportation can cause friction with the surface of the packaging bag, easily resulting in damage to the packaging bag. Therefore, if the double packaging bag described in Patent Document 1 is used as a packaging bag for polysilicon nuggets, for example, the vibrations of the polysilicon nuggets may cause friction with the packaging bag, potentially exposing the metal of the barrier layer. If the exposed metal is mixed with the polysilicon, there is a risk that the single-crystal silicon manufactured using this polysilicon as a raw material will be contaminated.

[0005] Therefore, the present invention aims to provide a means to prevent damage to the packaging bag when storing or transporting a package containing silicone material, such as polysilicon nuggets, using the packaging bag. [Means for solving the problem]

[0006] The inventors diligently studied to solve the above problem. As a result, from the outermost layer to the innermost layer, The material comprises, in this order, an outer layer mainly composed of a cyclic olefin resin or low-density polyethylene, a gas barrier layer mainly composed of an ethylene-vinyl alcohol copolymer, and a heat seal layer mainly composed of low-density polyethylene, with a density of 0.86 g / cm³. 3 More than 0.90g / cm 3 We have discovered that the above problems can be solved by using a multilayer film as a packaging material, which further comprises a water vapor barrier layer between the outer layer and the heat seal layer, with a polyolefin resin having the following density as the main component, and have completed the present invention.

[0007] In other words, according to one embodiment of the present invention, the layers are arranged in the following order from the outermost layer to the innermost layer: an outer layer mainly composed of a cyclic olefin resin or low-density polyethylene, a gas barrier layer mainly composed of an ethylene-vinyl alcohol copolymer, and a heat seal layer mainly composed of low-density polyethylene, with a density of 0.86 g / cm³. 3More than 0.90g / cm 3 A packaging material is provided, which includes a multilayer film further comprising a water vapor barrier layer between the outer layer and the heat seal layer, the water vapor barrier layer being mainly composed of a polyolefin resin having the following density. [Effects of the Invention]

[0008] According to the present invention, in packaging bags for silicone materials such as polysilicon nuggets, damage to the packaging bag becomes less likely to occur during storage and transportation of the package containing the silicone material. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a cross-sectional view showing one embodiment of a multilayer film constituting a packaging material according to one embodiment of the present invention. [Modes for carrying out the invention]

[0010] The following describes in detail embodiments for carrying out the present invention, but the present invention is not limited to the embodiments described below. The present invention can be modified in various ways without departing from its spirit.

[0011] One embodiment of the present invention comprises, in order from the outermost layer to the innermost layer, an outer layer mainly composed of a cyclic olefin resin or low-density polyethylene, a gas barrier layer mainly composed of an ethylene-vinyl alcohol copolymer, and a heat seal layer mainly composed of low-density polyethylene, with a density of 0.86 g / cm³. 3 More than 0.90g / cm 3A packaging material comprising a multilayer film further comprising a water vapor barrier layer containing a polyolefin resin having the following density as a main component between the outer layer and the heat seal layer. Using a multilayer film having such a configuration, for example, a packaging bag for a silicon material can be manufactured. When such a packaging bag is used as a packaging bag for a silicon material such as polysilicon nuggets, when storing or transporting a package in which the silicon material is packaged using the packaging bag, the packaging bag is less likely to be damaged.

[0012] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the following embodiments. The present invention can be variously modified without departing from the gist thereof. In the drawings, the same elements will be denoted by the same reference numerals, and redundant descriptions will be omitted. Also, the positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios.

[0013] 《Multilayer Film》 FIG. 1 is a schematic diagram schematically showing an embodiment of a multilayer film constituting a packaging material according to an embodiment of the present invention. The multilayer film 1 is a multilayer film having a six-layer structure. Specifically, the multilayer film 1 includes an outer layer 10 made of a cyclic olefin resin (COP), an adhesive layer 20 made of an adhesive resin, a gas barrier layer 30 made of an ethylene-vinyl alcohol copolymer (EVOH), an adhesive layer 20 made of an adhesive resin, and a linear low-density polyethylene (LLDPE) having a density of 0.88 g / cm 3 and a water vapor barrier layer 40 made of a mass mixture of an α-olefin copolymer and a heat seal layer 50 made of low-density polyethylene are laminated in this order. When this multilayer film 1 is used in the form of a packaging material, the outer layer 10 is located on the outermost layer and the heat seal layer 50 is located on the innermost layer.

[0014] The following describes each layer constituting the multilayer film according to this embodiment. In this specification, "a certain layer X contains a certain component Y as its main component" means that the mass content of component Y is the largest among the components contained in that layer X.

[0015] (outer layer) The outer layer 10 is a layer mainly composed of cyclic olefin resin (COP) or low-density polyethylene (LDPE). Conventionally, a technology is known that uses a rigid EVOH layer as the outer layer of a multilayer film, but in this case, there is a problem that curling (warping) is likely to occur due to the difference in shrinkage rate between the heat seal layer's constituent resin (e.g., polyethylene). In contrast, the multilayer film according to this embodiment suppresses the occurrence of curling (warping) as described above and improves workability by having the outer layer 10 mainly composed of COP or LDPE. Furthermore, although EVOH, the main component of the gas barrier layer described later, is prone to cracking, the COP or LDPE, the main component of the outer layer 10, functions as a protective layer against the gas barrier layer, which has the advantage of suppressing the occurrence of pinholes and holes caused by external impacts.

[0016] Examples of cyclic olefin resins (COPs) used in the outer layer 10 include norbornene polymers, vinyl alicyclic hydrocarbon polymers, and cyclic conjugated diene polymers. Among these, norbornene polymers are preferred. Examples of norbornene polymers include ring-opened polymers of norbornene monomers and norbornene copolymers (COCs) obtained by copolymerizing norbornene monomers with olefins such as ethylene. Furthermore, it is particularly preferable that the cyclic olefin resin is a hydrogenated ring-opened polymer of norbornene monomers or norbornene copolymers.

[0017] Norbornene monomers, which are raw materials for norbornene polymers, are alicyclic monomers having a norbornene ring. Examples of such norbornene monomers include norbornene, tetracyclododecene, ethylidene norbornene, vinyl norbornene, ethylidene tetracyclododecene, dicyclopentadiene, dimethanotetrahydrofluorene, phenyl norbornene, methoxycarbonyl norbornene, and methoxycarbonyl tetracyclododecene. These norbornene monomers may be used individually or in combination of two or more.

[0018] Norbornene copolymers (COCs) are obtained by copolymerizing a norbornene monomer with an olefin copolymerizable thereto. Examples of such olefins include olefins having 2 to 20 carbon atoms, such as ethylene, propylene, and 1-butene; cycloolefins, such as cyclobutene, cyclopentene, and cyclohexene; and non-conjugated dienes, such as 1,4-hexadiene. These olefins may be used individually or in combination of two or more. The content ratio of norbornene monomers in the norbornene copolymer (COC) is preferably 40 to 90 mol%, and more preferably 50 to 80 mol%. If the content ratio is within this range, the rigidity and processing stability of the film will be improved.

[0019] Examples of commercially available cyclic olefin resins that can be used include, as norbornene monomer ring-opening polymers (COPs), "ZEONOR" manufactured by Nippon Zeon Co., Ltd., and as norbornene copolymers (COCs), "APPEL" manufactured by Mitsui Chemicals, Inc. and "TOPAS" manufactured by Polyplastics Co., Ltd. Note that a single cyclic olefin resin (COP) may be used alone, or two or more may be used in combination.

[0020] The low-density polyethylene (LDPE) used in the outer layer 10 is, for example, branched low-density polyethylene obtained by high-pressure radical polymerization, preferably branched low-density polyethylene obtained by homopolymerizing ethylene by high-pressure radical polymerization. Since such low-density polyethylene has good compatibility with cyclic olefin resins, transparency can be maintained when blended. Furthermore, even when no other resins are used, adhesive strength between the outer layer and adjacent layers can be ensured, and its flexibility also provides good pinhole resistance.

[0021] The melt flow rate (MFR; measured at 190°C and 21.18N in accordance with JIS K7210) of low-density polyethylene is preferably 0.1 to 10 g / 10 min, more preferably 0.3 to 8.0 g / 10 min, and particularly preferably 0.8 to 6.0 g / 10 min. An MFR within this range is preferable because it improves extrusion moldability.

[0022] The melt tension (MT) of low-density polyethylene is preferably 2.0 to 15.0, and more preferably 4.0 to 13.0. A value within this range is preferable because it improves secondary moldability and pinhole resistance. This MT value is measured using a melt tension tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.). In this device, the low-density polyethylene is heated to 190°C, and the resin is extruded from a 2mmφ nozzle at a rate of 0.75 mL / min in a 23°C atmosphere to form strands. The tension is then measured when these strands are drawn back at a rate of 25 to 60 m / min with a 90 cm air gap.

[0023] As described above, the main component of the outer layer 10 is a cyclic olefin resin (COP) or low density polyethylene (LDPE). Therefore, the outer layer 10 may be composed only of the cyclic olefin resin (COP) and / or low density polyethylene (LDPE), but other resins other than these resins may be used in combination as long as the physical properties of the outer layer are not impaired. Examples of other resins include linear low density polyethylene (LLDPE) and the like. Further, the outer layer 10 may further contain components other than the resin. Examples of such components include anti-blocking agents (for example, zeolite, silica, PMMA, etc.).

[0024] The total blending amount of the cyclic olefin resin (COP) and low density polyethylene (a1) in the outer layer 10 is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 100% by mass with respect to 100% by mass of the total mass of the outer layer 10.

[0025] The density of the outer layer 10 is preferably 0.910 to 0.935 g / cm 3 and more preferably 0.915 to 0.935 g / cm 3 and still more preferably 0.920 to 0.935 g / cm 3 If the density of the outer layer 10 is within this range, it has appropriate rigidity and is preferable because the film forming property and extrusion suitability are improved.

[0026] The thickness of the outer layer 10 in the multilayer film is preferably 15 to 65 μm, and more preferably 25 to 55 μm. When the thickness of the outer layer 10 is 15 μm or more, there is an advantage that it is possible to suppress the decrease in the barrier property of EVOH due to the water vapor barrier property and suppress cracks from the outer surface flexibility to EVOH.

[0027] (Gas barrier layer) The gas barrier layer 30 is located inside the outer layer 10 and is a layer containing ethylene-vinyl alcohol copolymer (EVOH) as a main component.

[0028] Ethylene-vinyl alcohol copolymer (EVOH) is a resin obtained by saponifying a copolymer of ethylene and a vinyl ester monomer using an alkaline catalyst or the like. The content of ethylene repeating units in the EVOH constituting the EVOH layer is not particularly limited, but from the viewpoint of film formation stability, it is usually 29 mol% or more, preferably 32 mol% or more. Also, from the viewpoint of gas barrier properties, it is usually 47 mol% or less, preferably 44 mol% or less. Furthermore, the degree of saponification of EVOH is usually 90% or more, preferably 95% or more. By setting the content of ethylene structural units and the degree of saponification of EVOH within the above ranges, it tends to be possible to improve gas barrier properties and mechanical strength. The EVOH constituting the gas barrier layer may be one type or two or more types. Note that EVOH is not limited to those produced by saponification, as long as the chemical structure is similar.

[0029] The gas barrier layer 30 is not particularly limited as long as it contains EVOH as its main component, and may contain components other than EVOH. From the viewpoint of improving the gas barrier properties of the multilayer film, the content of EVOH, which is the main component of the gas barrier layer 30, is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, particularly preferably 98% by mass or more, and most preferably 100% by mass, relative to the total amount of the gas barrier layer 30. The upper limit of the EVOH content in the gas barrier layer 30 is not particularly limited, and may be, for example, 100% by mass or 99% by mass.

[0030] The thickness of the gas barrier layer 30 in the multilayer film is preferably 3 to 30 μm, more preferably 5 to 25 μm, even more preferably 8 to 20 μm, particularly preferably 10 to 18 μm, and most preferably 12 to 15 μm. With this configuration, the occurrence of cracks and pinholes caused by stress and interlayer strain under high temperature and high humidity conditions, which tended to occur in the vapor-deposited film constituting prior art vapor-deposited films during transportation or vacuum packaging of the package, can be effectively suppressed, and a decrease in barrier function can be prevented. In addition, there is the advantage that the deterioration of contents such as polysilicon can be prevented when the multilayer film is used as a packaging bag.

[0031] (Water vapor barrier layer) The water vapor barrier layer 40 is located inside the outer layer 10 and has a water vapor barrier capacity of 0.86 g / cm³. 3 More than 0.90g / cm 3 The layer mainly consists of a polyolefin resin (PO) having the following density. In the multilayer film according to this embodiment, the arrangement of the outer layer, gas barrier layer and water vapor barrier layer may be in the order of outer layer / gas barrier layer / water vapor barrier layer from the outermost layer to the innermost layer, or in the order of outer layer / water vapor barrier layer / gas barrier layer, but the order of outer layer / gas barrier layer / water vapor barrier layer is more preferred.

[0032] Examples of polyolefin resins (PO) used in the water vapor barrier layer 40 include linear low-density polyethylene (LLDPE) and polyolefin elastomers. Here, "polyolefin elastomer" refers to a polymer composed of olefin monomers that exhibits low crystallinity and rubber elasticity. The polyolefin resin (PO) preferably contains this polyolefin elastomer, and more preferably contains a copolymer of ethylene and α-olefin (ethylene-α-olefin copolymer). This compensates for the hardness and brittleness of the film caused by the constituent resins of the gas barrier layer and water vapor barrier layer, and provides sufficient flexibility, high sealing strength, and puncture strength to the entire multilayer film. As a result, it is possible to reduce the risk of damage during transportation while ensuring the good conformability required during degassing and vacuum packaging of the silicone material.

[0033] Specific examples of ethylene-α-olefin copolymers include, for example, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, and ethylene-1-octene copolymer. Commercially available ethylene-α-olefin copolymers include, for example, "Tafmer" manufactured by Mitsui Chemicals, Inc., "Engage" manufactured by The Dow Chemical Company, "Exact" and "Exceed" manufactured by ExxonMobil, and "Kernel" manufactured by Nippon Polyethylene Co., Ltd. Other polyolefin elastomers besides ethylene-α-olefin copolymers, such as propylene elastomers, ethylene-propylene rubber, and butene-1-based copolymers, may also be used as polyolefin elastomers. Furthermore, one type of polyolefin resin (PO) may be used alone, or two or more types may be used in combination.

[0034] The density of the polyolefin resin (PO) contained in the water vapor barrier layer 40 is 0.86 g / cm³. 3 More than 0.90g / cm 3 Anything below this limit is acceptable, preferably 0.87 g / cm³ 3 More than 0.89g / cm 3The following applies. A single polyolefin resin (PO) with such density may be used alone, or two or more may be used in combination. Incidentally, the density is 0.90 g / cm³. 3 The polyolefin resin (PO) described below has somewhat inferior water vapor barrier properties. On the other hand, resins such as COP, which have been used as constituent materials for water vapor barrier layers, are hard and brittle like glass, and there was a risk that the water vapor barrier properties and pinhole resistance would decrease due to the occurrence of cracks. In contrast, in the multilayer film according to this embodiment, although polyolefin resin (PO) has somewhat inferior water vapor barrier properties as described above, it is intentionally included as a constituent material for the water vapor barrier layer 40, thereby suppressing the occurrence of cracks in the water vapor barrier layer and the problems caused by them.

[0035] When the water vapor barrier layer 40 contains a polyolefin-based elastomer as a polyolefin-based resin, the polyolefin-based elastomer content in the multilayer film is preferably 20 to 50% by mass, more preferably 20 to 35% by mass, even more preferably 20 to 30% by mass, and particularly preferably 20 to 25% by mass, based on 100% by mass of the total mass of the multilayer film, from the viewpoint of having excellent mechanical strength (tear strength and pinhole resistance) of the multilayer film.

[0036] The water vapor barrier layer 40 is not particularly limited as long as it mainly contains a polyolefin resin (PO) having the predetermined density described above, and may also contain components other than the polyolefin resin (PO). Other resins other than polyolefin resin (PO) may also be used in combination. Examples of other resins include cyclic olefin resins (COP). The cyclic olefin resin (COP) used in the water vapor barrier layer 40 may be the same as the cyclic olefin resin (COP) used in the outer layer 10 described above. Furthermore, the water vapor barrier layer 40 may contain components other than resins.

[0037] The content of the polyolefin resin (PO) having a predetermined density, which is the main component of the water vapor barrier layer 40, is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, particularly preferably 98% by mass or more, and most preferably 100% by mass, based on the total amount of the water vapor barrier layer 40, from the viewpoint of improving the water vapor barrier properties of the multilayer film. The upper limit of the content of the polyolefin resin (PO) having a predetermined density in the water vapor barrier layer 40 is not particularly limited, and may be, for example, 100% by mass or 99% by mass.

[0038] The thickness of the water vapor barrier layer 40 in the multilayer film is preferably 80 to 180 μm, and more preferably 110 to 160 μm.

[0039] (Adhesive layer) In this embodiment, it is preferable that the multilayer film further comprises an adhesive layer 20 containing an adhesive resin as its main component at each interface of the outer layer 10, the gas barrier layer 30, and the water vapor barrier layer 40.

[0040] Examples of adhesive resins include acid-modified olefin resins obtained by chemically bonding monobasic unsaturated fatty acids such as acrylic acid and methacrylic acid, or anhydrides of dibasic unsaturated fatty acids such as maleic acid, phthalic acid, and itaconic acid, i.e., maleic anhydride, to polyethylene, polypropylene, copolymers of these with different α-olefins, or ethylene-vinyl acetate copolymers. From the viewpoint of improving the gas barrier properties and pinhole resistance of multilayer films, it is preferable to use acid-modified polyolefins as adhesive resins, and more preferable to use modified polyethylene. In this embodiment, a polyolefin resin is used as the main component of the water vapor barrier layer of the multilayer film, but the adhesive resin and the above-mentioned polyolefin resin differ in that the former contains additive components such as maleic anhydride and acrylic acid in addition to the polyolefin component to improve adhesion.

[0041] When the multilayer film includes an adhesive layer 20, the thickness of the adhesive layer 20 (single layer thickness) is preferably 5 to 25 μm, and more preferably 10 to 20 μm.

[0042] (Heat seal layer) The heat seal layer 50 is located inside the water vapor barrier layer 40 and is a layer mainly composed of low-density polyethylene (LDPE). Here, since LDPE has less volatilization (outgassing) of low molecular weight components compared to LLDPE, when the packaging material according to this embodiment is applied to the packaging of silicone materials, it is possible to effectively prevent outgassing from the heat seal layer 50 from contaminating the silicone material.

[0043] The low-density polyethylene (LDPE) used in the heat-seal layer 50 may be the same as the low-density polyethylene (LDPE) used in the outer layer 10 as described above.

[0044] The heat seal layer 50 may consist solely of low-density polyethylene (LDPE), but other resins may be used in combination, as long as they do not impair the physical properties of the heat seal layer. Examples of other resins include polyolefin resins such as high-density polyethylene (HDPE), medium-density polyethylene (MDPE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), ethylene-methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-ethyl methacrylate copolymer, ionomer resin, and linear low-density polyethylene (LLDPE). Furthermore, the heat seal layer 50 may also contain thermoplastic resins such as ethylene-ethyl acrylate copolymer (EEA), ethylene-acrylic acid copolymer (EAA), heat-sealable polyethylene terephthalate (heat-sealable PET), and heat-sealable ethylene-vinyl alcohol copolymer (heat-sealable EVOH). Heat-sealable PET refers to PET with a lower melting point than ordinary PET, making it suitable for heat sealing. Examples include co-extruded heat-sealable PET, coated heat-sealable PET, and self-adhesive (hot-melt) heat-sealable PET. The heat-seal layer 50 may also contain components other than resin. Examples of such components include surfactants and antiblocking agents (e.g., zeolite, silica, PMMA, etc.).

[0045] From the viewpoint of excellent heat sealing speed and heat sealing strength, the amount of low-density polyethylene (LDPE) blended in the heat seal layer 50 is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and most preferably 100% by mass, based on 100% by mass of the total mass of the heat seal layer 50.

[0046] The density of the heat seal layer 50 is preferably 0.910 to 0.935 g / cm³. 3 More preferably, 0.915 to 0.935 g / cm³ 3And more preferably 0.920~0.935 g / cm³ 3 That is the case.

[0047] The thickness of the heat seal layer 50 in the multilayer film is preferably 10 to 50 μm, and more preferably 20 to 40 μm. A thickness of 10 μm or more for the heat seal layer 50 has the advantage of providing more stable heat seal strength.

[0048] The multilayer film according to this embodiment essentially comprises the outer layer, gas barrier layer, water vapor barrier layer, and heat seal layer described above. However, the multilayer film may further comprise layers other than these, such as various functional layers. Examples of such functional layers include heat-resistant layers, conductive layers, and antibacterial layers.

[0049] The total thickness of the multilayer film according to this embodiment is preferably 100 to 300 μm, more preferably 150 to 250 μm, and even more preferably 180 to 200 μm. A total thickness of 150 μm or more of the multilayer film has the advantage of being resistant to punctures from the contents and less likely to tear.

[0050] The packaging bag according to this embodiment is obtained by forming the multilayer film described above into a cylindrical shape and then sealing it. Such a packaging bag has the advantage that, when storing or transporting a package containing, for example, a silicone material such as polysilicon nuggets, it is less likely to be damaged and the risk of foreign matter contamination is extremely low.

[0051] From the above, the packaging material according to one embodiment of the present invention is preferably used for packaging silicone materials. Furthermore, according to another embodiment of the present invention, a packaging bag for silicone materials is provided, comprising the packaging material according to one embodiment of the present invention, wherein a heat-seal layer is disposed on the inside of the bag. Furthermore, it is preferable that the packaging bag for silicone materials is composed of a double bag. That is, a preferred embodiment of the above-described packaging bag for silicone materials comprises a first bag and a second bag, which is made of the packaging bag for silicone materials according to one embodiment of the present invention and disposed inside the first bag, wherein the second bag is disposed inside the first bag without being fixed to the first bag. Conventionally, a technique is known in which a barrier layer is provided on the outer bag for packaging silicone materials, but in this case, if the outer bag is damaged during transportation of the package, there is a risk that the contents such as silicone material may be contaminated through the inner bag, which does not have a barrier layer. In contrast, with the packaging bag described above, a packaging bag (second bag) made of the packaging material according to this embodiment having a barrier layer is used as an inner bag, thus reducing the risk of such contamination.

[0052] In addition, according to another embodiment of the present invention, a packaging body for a silicone material is also provided, comprising a packaging bag for the silicone material described above and the silicone material contained within the packaging bag for the silicone material. In particular, the silicone material preferably includes polysilicon nuggets.

[0053] Method for manufacturing multilayer films A multilayer film constituting a packaging material according to one embodiment of the present invention can be appropriately manufactured by a person skilled in the art, taking into account the common technical knowledge as of the filing date of this application, based on the description in the Examples section below. As an example of a method for manufacturing a multilayer film, a cylindrical body of unstretched multilayer film can be produced by a downward air-cooled inflation molding method using a co-extrusion annular die capable of co-extruding each constituent resin of each layer, such that the innermost layer is located inside the cylinder, and the end is slit and cut to a predetermined length to obtain a multilayer film in the shape of a cylinder. With such a manufacturing method, the lamination process that was required in the manufacture of prior art vapor-deposited films is unnecessary. Therefore, there is an advantage in that the elution of organic components derived from adhesives that occurred in the conventional lamination process and the increase in costs for maintaining cleanliness can be suppressed.

[0054] An inflation film manufacturing apparatus that can be used in the production of multilayer films comprises an annular die, a mechanism that discharges air from the center of the annular die to expand the molten resin, and an air cooling mechanism for cooling and solidifying the inflation film.

[0055] To explain the above manufacturing method in more detail, the resin, which has been melted and kneaded by the extruder, is extruded in a cylindrical shape from an annular die. The melting temperature of the resin supplied to the annular die is preferably in the range of 20 to 120°C higher than the melting point of the resin at the resin extrusion port. The molten resin extruded from the annular die expands due to the air pressure sent inside, forming a cylindrical inflation film (inflation bubble). The cooled and solidified inflation film is then folded flat by pinch rolls and wound onto a winding roll via guide rolls. Subsequently, the cylindrical multilayer film produced in this way is formed into a bag shape with three sides sealed, filled with contents, packaged, and then the remaining piece is heat-sealed to produce a package containing the contents. [Examples]

[0056] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0057] 《Production of multilayer films》 [Examples and Comparative Examples] Using the raw materials shown in Tables 1 and 2 below, multilayer films were manufactured in all experimental examples except Comparative Example 2 by a method including an extrusion process. In Comparative Example 2, a multilayer film was manufactured by laminating three layers of film. Details of each raw material shown in Tables 1 and 2 are as follows. Note that "(50)" in the raw material column of Tables 1 and 2 means that the resin content in that layer is 50% by mass.

[0058] <Raw materials> • LDPE (Low-density polyethylene, product name "Novatec®", manufactured by Nippon Polyethylene Co., Ltd.) • AD (adhesive resin, product name "Modic®", manufactured by Mitsubishi Chemical Corporation) • EVOH (ethylene-vinyl alcohol copolymer, product name "EVAL®", manufactured by Kuraray Co., Ltd.) COP (Norbornene-based monomer ring-opening polymer (density 1.01 g / cm³)) 3 (Cycloolefin polymer), product name "Zeonor®", manufactured by Nippon Zeon Co., Ltd.) • POE (Polyolefin-based elastomer (ethylene-α-olefin copolymer), product name "Tafmer", manufactured by Mitsui Chemicals, Inc.) ·LLDPE(I) (density 0.88g / cm 3 Linear low-density polyethylene, product name "Kernel (registered trademark)", manufactured by Japan Polyethylene Co., Ltd. ·LLDPE(II) (density 0.938g / cm 3 Linear low-density polyethylene, product name "Evolu®", manufactured by Prime Polymer Corporation. • Commercially available high-barrier films made of laminated silica-deposited stretched PET film, ONY (biaxially oriented nylon) film, and sealant film (polyethylene film). <Preparation of multilayer films for Examples 1-4 and Comparative Examples 1 and 3-5> In the extrusion process of Examples 1-4 and Comparative Example 1, cylindrical bodies of unstretched laminated films having the layer configuration shown in Table 1 were produced by an upward air-cooled inflation molding method using a 6-layer co-extrusion annular die. During this process, the heat-seal layer was positioned on the inside of the cylindrical body. Next, the ends of the produced cylindrical bodies were slit to cut them to a predetermined length, thereby obtaining the multilayer films of Examples 1-4 and Comparative Example 1.

[0059] <Comparative Example 2> The commercially available high-barrier film mentioned above was used as the multilayer film in Comparative Example 2.

[0060] Evaluation of multilayer film The multilayer films of each example and comparative example were evaluated using the following method. The results are shown in Tables 1 and 2 below.

[0061] <Oxygen permeability> The oxygen permeability (23°C, 75%RH) of a multilayer film was measured in accordance with JIS K7126-2:2006 "Plastics - Films and Sheets - Gas Permeability Test Method". The measured oxygen permeability was 1.5 [cc / m²]. 2 It is preferable that it is less than or equal to 24h·atm, and 1.0 [cc / m 2 It is more preferable that the ATM is 24 hours or less.

[0062] <Oxygen permeability after 200 Gelboflex tests> A gel flex test was performed in accordance with ASTM F392 under conditions of 23°C and 200 bending cycles. Subsequently, the oxygen permeability was measured using the same method as described above. The oxygen permeability was 1.5 [cc / m³]. 2 It is preferable that it is less than or equal to 24h·atm, and 1.0 [cc / m 2 It is more preferable that the ATM is 24 hours or less.

[0063] <Moisture permeability> The moisture permeability was measured under condition B (test temperature 40°C, test relative humidity 90%RH) in accordance with the isobaric method (cup type - gravimetric method) described in JIS Z0208:1976 / AMENDMENT 1:2021 "Test method for moisture permeability of moisture-proof packaging materials (cup method)". The measured moisture permeability was 1.0 g / m³. 2 It is preferable that it is 24 hours or less, and 1.5 g / m 2 It is preferable that it be less than 24 hours.

[0064] <Moisture permeability after 200 Gelboflex tests> A Gelboflex test was performed in accordance with ASTM F392 under conditions of 23°C and 200 bending cycles. Subsequently, the water vapor permeability was measured using the same method as described above. This water vapor permeability was 1.5 g / m². 2 It is preferable that it is 24 hours or less, and 1.0 g / m³ 2 It is preferable that it be less than 24 hours.

[0065] <Heat seal strength> The heat-sealed layers of the films were placed facing each other, and heat-sealed using a heat sealer manufactured by Tester Industries Co., Ltd. under the following conditions: a sealing pressure of 0.2 MPa, a sealing time of 1 second, a sealing width of 5 mm, and a sealing temperature of 140 to 160°C, varied in 2°C increments. After heat sealing, the film was cut into 15 mm wide x 80 mm pieces, and T-shaped peeling was performed using a tensile testing machine manufactured by Shimadzu Corporation at a tensile speed of 300 mm / min to measure the heat-seal strength [N / 15 mm] of the heat-sealed portion. This heat-seal strength is preferably 35 [N / 15 mm] or higher, and more preferably 43 [N / 15 mm] or higher.

[0066] <MD tear strength and TD tear strength> In accordance with JIS K7128-1:1998 "Plastics - Test methods for tear strength of films and sheets," the tear strength [N] in the flow direction (MD: Machine Direction) and the width direction (TD: Transverse Direction) was measured using the trouser tearing method. The tear strength is preferably 4 [N] or higher in the MD direction, more preferably 7 [N] or higher, and preferably 5 [N] or higher in the TD direction, more preferably 11 [N] or higher.

[0067] <Piercing strength> The puncture strength [N] was measured in accordance with JIS Z1707:2019 "General Rules for Plastic Films for Food Packaging" (7.4 Puncture Strength Test). This puncture strength is preferably 8 [N] or higher, and more preferably 10 [N] or higher.

[0068] <500-cycle Gelboflex test (flexibility)> A Gelboflex test was performed in accordance with ASTM F392 under conditions of 23°C and 500 bending cycles. After the test, the multilayer film was visually inspected to confirm the number of pinholes observed in the film. The number of pinholes should preferably be 9 or less, and more preferably 3 or less.

[0069] [Table 1]

[0070] [Table 2]

[0071] As can be seen from the results of the above evaluation, the multilayer film according to one embodiment of the present invention exhibited high mechanical strength and maintained excellent barrier properties even after the Gelboflex test.

[0072] From the above, it can be said that packaging bags made of this multilayer film are less prone to damage during storage and transportation of packages containing silicon materials, such as polysilicon nuggets. This is thought to be because, unlike the vapor-deposited film of Comparative Example 2, the occurrence of cracks in the barrier layer caused by differences in strain and elongation between each layer is suppressed. Furthermore, the inventors are the first to have achieved such performance with a co-extruded multilayer film that does not require a vapor-deposited film.

[0073] Furthermore, the multilayer film according to the present invention has the advantage of being able to be manufactured without requiring a lamination process like that in Comparative Example 2. [Explanation of symbols]

[0074] 1. Multilayer film, 10 outer layer, 20 adhesive layer, 30 Gas barrier layer, 40 Water vapor barrier layer, 50 heat-seal layers.

Claims

1. From the outermost layer to the innermost layer, An outer layer mainly composed of cyclic olefin resin or low-density polyethylene, A gas barrier layer mainly composed of an ethylene-vinyl alcohol copolymer, A heat-seal layer containing low-density polyethylene as the main component, and in this order, 0.86 g / cm³ ３ 0.90g / cm or more ３ A packaging material comprising a multilayer film further comprising a water vapor barrier layer between the outer layer and the heat seal layer, the water vapor barrier layer being mainly composed of a polyolefin resin having the following density.

2. The packaging material according to claim 1, wherein the polyolefin resin includes a polyolefin elastomer.

3. The packaging material according to claim 2, wherein the polyolefin elastomer comprises an ethylene-α-olefin copolymer.

4. The packaging material according to claim 2, wherein the content of the polyolefin elastomer is 20 to 50% by mass relative to 100% by mass of the total mass of the multilayer film.

5. The packaging material according to claim 1, further comprising an adhesive layer mainly composed of an adhesive resin between the outer layer and the gas barrier layer, and / or between the gas barrier layer and the water vapor barrier layer.

6. The packaging material according to claim 1, wherein the thickness of both the gas barrier layer and the water vapor barrier layer is 5 μm or more.

7. A packaging material according to any one of claims 1 to 6, for use in packaging silicone materials.

8. A packaging bag made of silicone material, comprising the packaging material according to any one of claims 1 to 6, wherein the heat-seal layer is disposed on the inside of the bag.

9. The first bag and A second bag is placed inside the first bag, Equipped with, The second bag is placed inside the first bag without being fixed to the first bag. The second bag is a packaging bag made of silicone material, as described in claim 8.

10. A packaging bag for a silicone material according to claim 9, The silicone material contained in the packaging bag for the aforementioned silicone material, A packaging body made of silicone material, equipped with the following features.

11. The packaging of the silicon material according to claim 10, wherein the silicon material includes polysilicon nuggets.

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