Packaging film, packaging bag, and packaging product

Abstract

To provide: a packaging film capable of having excellent gas barrier properties while inhibiting the reduction in the ratio of a polyolefin-based resin in the entire packaging film; and a packaging bag and a packaging product.SOLUTION: The packaging film includes a gas barrier film, an adhesive layer and a sealant layer in this order. The gas barrier film has a substrate layer and a deposited layer, where the substrate layer has: a polyolefin-based substrate layer containing a polyolefin-based resin; and a heat-resistant layer. The heat-resistant layer includes a high-melting-point resin having a melting point equal to or higher than 180°C. The adhesive layer can be obtained by bonding an adhesive resin composition containing a polyolefin-based adhesive resin to a gas barrier film through melt extrusion. The sealant layer contains a polyolefin-based resin.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a packaging film, a packaging bag, and a packaged product.

Background Art

[0002] In recent years, from the viewpoint of facilitating material recycling, the mono-materialization of packaging films has been promoted. On the other hand, packaging films are also required to retain functions such as gas barrier properties. In contrast, a gas barrier film in which a gas barrier layer is provided by vapor deposition on a polyolefin-based substrate layer containing a polyolefin-based resin, and a polyolefin-based sealant layer containing a polyolefin-based resin are bonded together by dry lamination using an adhesive capable of forming a non-polyolefin-based resin is conceivable. However, in such a packaging film, since an adhesive capable of forming a non-polyolefin-based resin is used, the quality of the recycled resin obtained by material recycling of the packaging film deteriorates. Therefore, in order to suppress the deterioration of the quality of the recycled resin, instead of an adhesive capable of forming a non-polyolefin-based resin, a laminate using an adhesive resin composition containing a polyolefin-based adhesive resin such as maleic anhydride graft polymerized polypropylene as an adhesive layer is known (see Patent Document 1 below).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, although the laminate described in Patent Document 1 above can increase the ratio of the polyolefin-based resin in the entire laminate, there is still room for improvement in terms of gas barrier properties.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a packaging film, a packaging bag, and a packaged product that can have excellent gas barrier properties while suppressing a decrease in the ratio of the polyolefin resin in the entire packaging film.

Means for Solving the Problems

[0006] To solve the above problems, one aspect of the present disclosure provides a packaging film including a gas barrier film, an adhesive layer, and a sealant layer in this order, wherein the gas barrier film has a base material layer and a vapor deposition layer, the base material layer has a polyolefin-based base material layer containing a polyolefin resin and a heat-resistant layer, the heat-resistant layer contains a high melting point resin having a melting point of 180° C. or higher, the adhesive layer is obtained by melt-extruding and laminating an adhesive resin composition containing a polyolefin-based adhesive resin onto the gas barrier film, and the sealant layer contains a polyolefin resin. According to the above packaging film, it is possible to have excellent gas barrier properties while suppressing a decrease in the ratio of the polyolefin resin in the entire packaging film.

[0007] The inventors of the present disclosure presume that the reason for obtaining the above effects is as follows. That is, when the adhesive resin composition containing the polyolefin-based adhesive resin is melt-extruded and laminated onto the gas barrier film, the heat of the adhesive resin composition is transmitted to the base material layer through the vapor deposition layer. The polyolefin-based adhesive resin composition is at a high temperature when it comes into contact with the gas barrier film, but then it is cooled by a cooling roll and becomes low temperature. Along with this, the polyolefin-based base material layer attempts to expand and then contract. At this time, the heat-resistant layer containing the high melting point resin having a melting point of 180° C. or higher contained in the base material layer suppresses the expansion of the polyolefin-based base material layer due to heat, so the contraction due to cooling is also suppressed. As a result, the easily cracked vapor deposition layer is suppressed from expanding and contracting. As a result, the packaging film can have excellent gas barrier properties. In addition, the base material layer has a heat-resistant layer in addition to the polyolefin-based base material layer. Since the heat-resistant layer contains a high-melting-point resin having a melting point of 180°C or higher, even if it is thin, it can effectively suppress the expansion and contraction of the polyolefin-based base material layer. Therefore, a decrease in the ratio of the polyolefin-based resin in the entire packaging film can be suppressed.

[0008] In the above packaging film, it is preferable that the heat-resistant layer is provided on the vapor deposition layer side of the polyolefin-based base material layer. In this case, since the heat-resistant layer is disposed between the vapor deposition layer and the polyolefin-based base material layer, even if the polyolefin-based base material layer attempts to expand and contract after the adhesive resin composition is laminated to the gas barrier film by melt extrusion to form an adhesive layer, the expansion and contraction of the heat-resistant layer are sufficiently suppressed. Therefore, the easily cracked vapor deposition layer is more suppressed from stretching and contracting, and the packaging film can have better gas barrier properties.

[0009] In the above packaging film, it is preferable that the polyolefin-based base material layer is a stretched film. In this case, the crystallinity of the polyolefin-based base material layer and the heat-resistant layer contained in the base material layer is improved, and the melting point can be raised. Therefore, the melting point difference between the sealant layer and the base material layer can be increased, and it becomes easier to suppress the melting of the base material layer during heat sealing of the packaging film.

[0010] In the above packaging film, it is preferable that the high-melting-point resin of the heat-resistant layer contains a polyamide resin. Since the melting point of the polyamide resin is high, even if the polyolefin-based base material layer attempts to expand and contract after the adhesive resin composition is laminated to the gas barrier film by melt extrusion, the expansion and contraction of the heat-resistant layer are more sufficiently suppressed, and the easily cracked vapor deposition layer is further suppressed from stretching and contracting, and the packaging film can have even better gas barrier properties.

[0011] In the above packaging film, it is preferable that the heat-resistant layer contains a high-melting-point resin having a melting point of 185°C or higher. In this case, even if the polyolefin-based substrate layer attempts to expand and contract after the adhesive resin composition is melt-extruded and laminated to the gas barrier film, the expansion and contraction of the heat-resistant layer are more sufficiently suppressed, the easily cracked vapor deposition layer is further suppressed from expanding and contracting, and the packaging film can have even better gas barrier properties. Further, according to the packaging film, since the heat-resistant layer contains a high-melting-point resin having a melting point of 185°C or higher, a decrease in gas barrier properties can be suppressed even after a wet heat treatment such as a retort treatment or a boiling treatment.

[0012] In the above packaging film, the ratio of the thickness of the heat-resistant layer to the thickness of the gas barrier film is preferably 50% or less. In this case, the ratio of the polyolefin-based resin in the entire packaging film can be increased, and the recyclability of the packaging film can be enhanced.

[0013] In the above packaging film, it is preferable that the gas barrier film further includes an anchor coat layer containing a polyurethane resin between the vapor deposition layer and the substrate layer. In this case, even if the polyolefin-based substrate layer expands and contracts after the adhesive resin composition is melt-extruded and laminated to the gas barrier film, the expansion stress and contraction stress transmitted from the substrate layer to the vapor deposition layer are easily relaxed by the anchor coat layer containing a polyurethane resin, so that the easily cracked vapor deposition layer is further suppressed from expanding and contracting, and the packaging film can have even better gas barrier properties.

[0014] In the above packaging film, it is preferable that the gas barrier film further includes a coating layer that coats the vapor deposition layer between the vapor deposition layer and the polyolefin-based adhesive resin layer. In this case, when the adhesive resin composition expands and contracts after the adhesive resin composition is melt-extruded and laminated to the gas barrier film, the expansion stress and contraction stress are not directly transmitted to the vapor deposition layer but are indirectly transmitted through the coating layer, so that the expansion and contraction of the vapor deposition layer are suppressed.

[0015] Another aspect of the present disclosure provides a packaging bag including the above-described packaging film. The above packaging bag includes the above-described packaging film. According to the packaging film, it is possible to have excellent gas barrier properties while suppressing a decrease in the ratio of the polyolefin resin in the entire packaging film. Therefore, according to the above packaging bag, it is possible to have excellent gas barrier properties while suppressing a decrease in the ratio of the polyolefin resin in the entire packaging bag.

[0016] Still another aspect of the present disclosure provides a packaging product including the above packaging bag and contents accommodated in the packaging bag. The above packaging product includes the above-described packaging bag. According to the packaging bag, it is possible to have excellent gas barrier properties while suppressing a decrease in the ratio of the polyolefin resin in the entire packaging bag. Therefore, according to the packaging product, recycling after opening can be easily performed, and deterioration of the quality of the contents can also be suppressed.

Advantages of the Invention

[0017] According to the present disclosure, there are provided a packaging film, a packaging bag, and a packaging product that can have excellent gas barrier properties while suppressing a decrease in the ratio of the polyolefin resin in the entire packaging film.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present disclosure will be described in detail. However, the present invention is not limited to the following embodiments.

[0020] <Packaging Film> First, an embodiment of the packaging film of the present disclosure will be described with reference to FIG. 1. FIG. 1 is a cross-sectional view showing an embodiment of the packaging film of the present disclosure.

[0021] The packaging film 100 shown in FIG. 1 includes a gas barrier film 10, an adhesive layer 60, and a sealant layer 70 in this order. The gas barrier film 10 has a base material layer 20 and a vapor deposition layer 40. The base material layer 20 has a polyolefin-based base material layer 21 containing a polyolefin-based resin and a heat-resistant layer 22. The heat-resistant layer 22 contains a high-melting-point resin having a melting point of 180°C or higher. The adhesive layer 60 is obtained by melt-extruding and laminating an adhesive resin composition containing a polyolefin-based adhesive resin onto the gas barrier film 10. The sealant layer 70 contains a polyolefin-based resin. Note that the packaging film 100 may further include an anchor coat layer 30 between the vapor deposition layer 40 and the base material layer 20. Further, the packaging film 100 may further include a coating layer 50 that coats the vapor deposition layer 40 between the vapor deposition layer 40 and the adhesive layer 60.

[0022] According to the above packaging film 100, it is possible to have excellent gas barrier properties while suppressing a decrease in the ratio of the polyolefin-based resin in the entire packaging film 100.

[0023] Hereinafter, the gas barrier film 10, the adhesive layer 60, and the sealant layer 70 will be described in detail.

[0024] (1) Gas barrier film The gas barrier film 10 has a base material layer 20 and a vapor deposition layer 40. The base material layer 20 has a polyolefin-based base material layer 21 containing a polyolefin-based resin and a heat-resistant layer 22. The base material layer 20 may further include an adhesive layer (hereinafter, also referred to as a "base material adhesive layer") between the polyolefin-based base material layer 21 and the heat-resistant layer 22 as necessary. Further, the gas barrier film 10 may further include a printing layer as necessary.

[0025] (Polyolefin-based substrate layer) The polyolefin-based substrate layer 21 contains a polyolefin-based resin. Specific examples of the polyolefin-based resin include polyethylene-based resins and polypropylene-based resins. Examples of the polyethylene-based resin include low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), linear low-density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, ethylene-(meth)acrylic acid copolymer, and the like. Examples of the polypropylene-based resin include, for example, homopolypropylene, block polypropylene, random polypropylene, and propylene-α-olefin copolymer. Examples of α-olefin include ethylene, 1-butene, and the like. Among these, from the viewpoint of heat resistance, polypropylene-based resins are preferred. Among the polypropylene-based resins, when emphasizing the rigidity and heat resistance of the packaging bag obtained using the packaging film 100, it is preferable to use a homopolymer. Also, the polyolefin-based resin may be a biomass-derived polyolefin-based resin or a mechanically recycled or chemically recycled polyolefin-based resin.

[0026] The polyolefin-based substrate layer 21 may have a single-layer structure or a multilayer structure. By providing the substrate layer 20 with the polyolefin-based substrate layer 21, the heat resistance and oil resistance of the packaging film 100 produced using the substrate layer 20 can be improved.

[0027] The polyolefin-based substrate layer 21 may be a stretched film or an unstretched film, but from the viewpoint of gas barrier properties, it is preferably a stretched film. Here, examples of the stretched film include a uniaxially stretched film and a biaxially stretched film, and a biaxially stretched film is preferred because it can improve the heat resistance of the packaging film 100.

[0028] The content of the polyolefin-based resin in the polyolefin-based substrate layer 21 is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0029] The polyolefin-based substrate layer 21 may contain additives as required. Examples of the additives include crosslinking agents, antioxidants, antiblocking agents, slip agents, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

[0030] The thickness of the polyolefin-based substrate layer 21 is preferably 5 μm or more, and more preferably 10 μm or more. By setting the thickness of the polyolefin-based substrate layer 21 to 5 μm or more, the strength and heat resistance of the substrate layer 20 can be further improved. The thickness of the polyolefin-based substrate layer 21 is preferably 40 μm or less, and more preferably 30 μm or less. By setting the thickness of the polyolefin-based substrate layer 21 to 40 μm or less, the processability of the substrate layer 20 can be further improved, and flexibility can be imparted to the packaging film 100.

[0031] The polyolefin-based substrate layer 21 may be surface-treated. Thereby, the adhesion with the heat-resistant layer 22 can be improved. The method of the surface treatment is not particularly limited, and examples thereof include corona discharge treatment, ozone treatment, low-temperature plasma treatment, glow discharge treatment, and oxidation treatment using a chemical.

[0032] (Heat-resistant layer) The heat-resistant layer 22 contains a high-melting-point resin having a melting point of 180° C. or higher. Thereby, when the adhesive resin composition is laminated to the gas barrier film 10 by melt extrusion, even when the substrate layer 20 is cooled after the heat of the adhesive resin composition is transmitted to the substrate layer 20 through the vapor deposition layer 40, it becomes difficult to expand and contract, the expansion and contraction of the polyolefin-based substrate layer 21 can be suppressed, and the easily cracked vapor deposition layer 40 is suppressed from expanding and contracting. As a result, the packaging film 100 can have excellent gas barrier properties. As shown in FIG. 1, the heat-resistant layer 22 may be provided on the vapor deposition layer 40 side of the polyolefin-based substrate layer 21, or may be provided on the vapor deposition layer 40 side with respect to the polyolefin-based substrate layer 21. However, it is preferably provided on the vapor deposition layer 40 side of the polyolefin-based substrate layer 21. In this case, since the heat-resistant layer 22 is disposed between the vapor deposition layer 40 and the polyolefin-based substrate layer 21, even if the polyolefin-based substrate layer 21 attempts to expand and contract after the adhesive resin composition is melt-extruded and bonded to the gas barrier film 10 to form the adhesive layer 60, the expansion and contraction of the heat-resistant layer 22 are sufficiently suppressed. Therefore, the easily cracked vapor deposition layer 40 is more suppressed from stretching and shrinking, and the packaging film 100 can have better gas barrier properties.

[0033] The melting point of the high melting point resin is more preferably 185° C. or higher, further preferably 190° C. or higher, and particularly preferably 205° C. or higher. When the melting point of the high melting point resin is 185° C. or higher, even if the polyolefin-based substrate layer 21 attempts to expand and contract after the adhesive resin composition is melt-extruded and bonded to the gas barrier film 10, the expansion and contraction of the heat-resistant layer 22 are more sufficiently suppressed, and the easily cracked vapor deposition layer 40 is further suppressed from stretching and shrinking. Thus, the packaging film 100 can have even better gas barrier properties. Further, according to the packaging film 100, since the heat-resistant layer 22 contains a high melting point resin having a melting point of 185° C. or higher, a decrease in gas barrier properties can be suppressed even after a wet heat treatment such as a retort treatment or a boiling treatment. From the viewpoint of the film-forming property of the heat-resistant layer 22, the melting point of the high melting point resin is preferably 265° C. or lower, more preferably 260° C. or lower, and further preferably 250° C. or lower.

[0034] The high melting point resin only needs to have a melting point of 180° C. or higher. Examples of the high melting point resin include vinyl resins, polyamide resins, polyimide resins, polyester resins, and cellulose resins. These may be used alone or in combination of two or more.

[0035] Among them, polyester resin or polyamide resin is preferable. Since these resins have polar groups, the adhesiveness between the heat-resistant layer 22 and the vapor deposition layer 40 can be significantly improved, and the gas barrier property of the vapor deposition layer 40 can be effectively enhanced.

[0036] Examples of the vinyl resin include ethylene vinyl alcohol (EVOH). The ethylene content (mol%) in EVOH is preferably low, for example, preferably 35 mol% or less, more preferably 32 mol% or less.

[0037] Examples of the polyester resin include polyethylene terephthalate resin (PET) and polyethylene naphthalate resin (PEN).

[0038] Examples of the polyamide resin include nylon 6, nylon 6,6, MXD nylon, and amorphous nylon.

[0039] The high melting point resin is preferably a polyamide resin. Since the melting point of the polyamide resin is high, even when the polyolefin-based substrate layer 21 expands and contracts after the adhesive resin composition is laminated to the gas barrier film 10 by melt extrusion, the expansion and contraction of the heat-resistant layer 22 are more sufficiently suppressed, and the easily cracked vapor deposition layer 40 is further suppressed from stretching and shrinking, enabling the packaging film 100 to have a more excellent gas barrier property. Further, even after the packaging film 100 is bent, a decrease in the gas barrier property of the packaging film 100 can be suppressed, and the heat resistance of the packaging film 100 can be improved. Furthermore, even after the packaging film 100 is subjected to a wet heat treatment such as a retort treatment or a boiling treatment, a decrease in the gas barrier property can be suppressed. As the high melting point resin, nylon 6 is more preferable.

[0040] The content of the high melting point resin in the heat-resistant layer 22 is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more.

[0041] The thickness of the heat-resistant layer 22 is preferably 1 μm or more. When the thickness of the heat-resistant layer 22 is 1 μm or more, the expansion or contraction of the polyolefin-based substrate layer 21 can be effectively suppressed when the substrate layer 20 is heated or cooled. The thickness of the heat-resistant layer 22 is preferably 10 μm or less, and more preferably 5 μm or less. When the thickness of the heat-resistant layer 22 is 20 μm or less, the ratio of the polyolefin-based resin in the entire packaging film 100 can be increased, and the recyclability of the packaging film 100 can be improved.

[0042] In the above-mentioned packaging film 100, the ratio of the thickness of the heat-resistant layer 22 to the thickness of the gas barrier film 10 is preferably 50% or less, and more preferably 25% or less. When the ratio of the thickness of the heat-resistant layer 22 to the thickness of the gas barrier film 10 is 50% or less, the ratio of the polyolefin-based resin in the entire packaging film 100 can be increased, and the recyclability of the packaging film 100 can be improved. In the above-mentioned packaging film 100, the ratio of the thickness of the heat-resistant layer 22 to the thickness of the gas barrier film 10 may be 2.5% or more, 3.0% or more, or 5.0% or more. When the ratio of the thickness of the heat-resistant layer 22 to the thickness of the gas barrier film 10 is 5.0% or more, the expansion or contraction of the polyolefin-based substrate layer 21 can be effectively suppressed when the substrate layer 20 is heated or cooled.

[0043] (Substrate Adhesive Layer) The substrate adhesive layer contains a polyolefin-based adhesive resin. Examples of the polyolefin-based adhesive resin include acid-modified polypropylene-based resins and acid-modified polyethylene-based resins.

[0044] Examples of the acid-modified polypropylene-based resin include maleic acid-modified polypropylene-based resins. The maleic acid-modified polypropylene-based resin is a resin obtained by modifying a polypropylene-based resin with maleic acid.

[0045] Examples of the polypropylene resin include homopolypropylene, block polypropylene, random polypropylene, and propylene-α olefin copolymer. Examples of the α-olefin include ethylene and 1-butene.

[0046] Examples of the acid-modified polyethylene resin include maleic acid-modified polyethylene resin. The maleic acid-modified polyethylene resin is a resin obtained by modifying a polyethylene resin with maleic acid. Examples of the polyethylene resin include high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene obtained by copolymerizing ethylene and an α-olefin. Examples of the α-olefin include ethylene, 1-butene, and 1-hexane.

[0047] The thickness of the base material adhesive layer is not particularly limited, but it is preferably 1 μm or more. When the thickness of the base material adhesive layer is 1 μm or more, the adhesiveness between the polyolefin base material layer 21 and the heat-resistant layer 22 is effectively improved. The thickness of the base material adhesive layer may be 10 μm or less.

[0048] (Base material layer) The base material layer 20 can be obtained by coextrusion or the like.

[0049] The thickness of the base material layer 20 is not particularly limited, but it is preferably 20 μm or more. When the thickness of the base material layer 20 is 10 μm or more, the adhesiveness between the gas barrier film 10 and the sealant layer 70 is effectively improved. The thickness of the base material layer 20 may be 50 μm or less or 40 μm or less.

[0050] (Anchor coat layer) The anchor coat layer 30 is a layer for further improving the adhesion between the base material layer 20 and the vapor deposition layer 40, and is provided between the base material layer 20 and the vapor deposition layer 40.

[0051] The material constituting the anchor coat layer 30 is not particularly limited as long as it can improve the adhesion between the base material layer 20 and the vapor deposition layer 40, but preferably contains a polyurethane resin. In this case, even when the polyolefin-based base material layer 21 attempts to expand and contract after the adhesive resin composition is melt-extruded and bonded to the gas barrier film 10, not only is the expansion and contraction of the heat-resistant layer 22 sufficiently suppressed, but also the expansion stress and contraction stress transmitted from the base material layer 20 to the vapor deposition layer 40 are easily relaxed by the anchor coat layer 30 containing a polyurethane resin. Therefore, the easily cracked vapor deposition layer 40 is further suppressed from expanding and contracting, and the packaging film 100 can have even better gas barrier properties. Such a polyurethane resin is composed of, for example, a reaction product of an organosilane or an organometallic compound, a polyol compound, and an isocyanate compound. The organosilane is, for example, a trifunctional organosilane or a hydrolyzate of a trifunctional organosilane. The organometallic compound is, for example, a metal alkoxide or a hydrolyzate of a metal alkoxide. The metal element contained in the organometallic compound is, for example, Al, Ti, Zr, etc. The hydrolyzate of the organosilane and the hydrolyzate of the metal alkoxide only need to have at least one hydroxyl group each. From the viewpoint of transparency, the polyol compound is preferably an acrylic polyol. The isocyanate compound mainly functions as a crosslinking agent or a curing agent. The polyol compound and the isocyanate compound may be monomers or polymers.

[0052] The thickness of the anchor coat layer 30 is not particularly limited as long as it can improve the adhesion between the base material layer 20 and the vapor deposition layer 40, but it is preferably 20 nm or more, more preferably 50 nm or more, and even more preferably 100 nm or more. When the thickness of the anchor coat layer 30 is 20 nm or more, even if the polyolefin-based base material layer 21 expands and contracts after the adhesive resin composition is melt-extruded and laminated to the gas barrier film 10, the expansion stress and contraction stress transmitted from the base material layer 20 to the vapor deposition layer 40 by the anchor coat layer 30 containing the polyurethane resin are effectively relaxed. Therefore, the expansion and contraction of the easily cracked vapor deposition layer 40 are less likely to occur, and the packaging film 100 can have even better gas barrier properties. From the viewpoint of suppressing a decrease in the ratio of the polyolefin-based resin in the entire packaging film 100, the thickness of the anchor coat layer 30 is preferably 2,000 nm or less. In this case, compared with the case where the thickness of the anchor coat layer 30 exceeds 2,000 nm, a decrease in gas barrier properties can be more effectively suppressed even after a wet heat treatment such as a retort treatment or a boiling treatment. The thickness of the anchor coat layer 30 is more preferably 1,000 nm or less.

[0053] (Vapor deposition layer) The vapor deposition layer 40 is a layer formed by vapor deposition, and the vapor deposition layer 40 is composed of an inorganic substance. Examples of the inorganic substance include metals and metal oxides.

[0054] Examples of the metal constituting the metal or metal oxide include at least one metal selected from the group consisting of Si, Al, Mg, Sn, Ti, and In. As the metal oxide, silicon oxide (SiOx), aluminum oxide (AlOx), or a mixture thereof is preferable. Since both SiOx and AlOx have excellent water vapor barrier properties, the water vapor barrier properties of the packaging film 100 can be improved. Among them, as the metal oxide, SiOx is preferable. In this case, the packaging film 100 can have even better water vapor barrier properties. The vapor deposition layer 40 may be composed of a single layer or a plurality of layers.

[0055] The thickness of the vapor deposition layer 40 is not particularly limited, but is preferably 5 nm or more. In this case, compared with the case where the thickness of the vapor deposition layer 40 is less than 5 nm, even after a heat and moisture treatment such as a retort treatment or a boiling treatment of the packaging film 100, a decrease in gas barrier properties can be more sufficiently suppressed. The thickness of the vapor deposition layer 40 is more preferably 8 nm or more, and particularly preferably 10 nm or more.

[0056] Also, the thickness of the vapor deposition layer 40 is preferably 300 nm or less. In this case, compared with the case where the thickness of the vapor deposition layer 40 exceeds 300 nm, even after a heat and moisture treatment such as a retort treatment or a boiling treatment of the packaging film 100, a decrease in gas barrier properties can be more suppressed. Also, the ratio of the polyolefin-based resin in the entire packaging film 100 can be increased, and the recyclability of the packaging film 100 can also be enhanced. The thickness of the vapor deposition layer 40 is more preferably 200 nm or less, and particularly preferably 100 nm or less.

[0057] (Coating layer) The coating layer 50 is a layer that coats the vapor deposition layer 40. When the gas barrier film 10 has the coating layer 50, when the adhesive resin composition is laminated to the gas barrier film 10 by melt extrusion and then the adhesive resin composition expands and contracts, the expansion stress and the contraction stress do not directly transmit to the vapor deposition layer 40, but indirectly transmit through the coating layer 50. Therefore, the expansion and contraction of the vapor deposition layer 40 are suppressed.

[0058] In the cross section of the coating layer 50, the hardness measured by the nanoindentation method is not particularly limited, but is preferably 1.15 GPa or less. In this case, when the adhesive resin composition is laminated to the gas barrier film 10 by melt extrusion and then the adhesive resin composition expands and contracts, the expansion stress and the contraction stress are effectively relaxed by the coating layer 50. Therefore, the easily cracked vapor deposition layer 40 is further more suppressed from being stretched and contracted. The hardness in the cross-section of the coating layer 50 is preferably 1.15 GPa or less, more preferably 1.0 GPa or less, and particularly preferably 0.7 GPa or less.

[0059] The hardness in the cross-section of the coating layer 50 may be 0.15 GPa or more or 0.20 GPa or more.

[0060] The hardness in the cross-section of the coating layer 50 is measured by the nanoindentation method. The nanoindentation method is a measurement method in which a quasi-static indentation test is performed on the target measurement object to obtain the mechanical properties of the sample. The hardness in the cross-section of the coating layer 50 is measured for a prepared measurement sample. The measurement sample (cross-section sample) is prepared as follows. That is, after corona treatment is performed on both sides of the packaging film 100, it is embedded in a visible light curable resin (Aronix LCR D-800, manufactured by Toagosei Co., Ltd.). Then, using an ultramicrotome Leica EM UC7 and a diamond knife Microstar LH, the packaging film 100 is cut perpendicular to the lamination direction. Finish processing is performed on the exposed cross-section under the conditions of a cutting thickness Feed of 100 nm and a cutting speed Speed of 1 mm / s to obtain a measurement sample. For the measurement, a Hysitron TI-Premier (trade name) manufactured by Bruker Japan Co., Ltd. is used as the measurement device, and a Berkovich type diamond indenter manufactured by Bruker Japan Co., Ltd. is used as the indenter. The measurement conditions are as follows. · Temperature: room temperature (25 °C) · Mode: load control mode · Indentation and unloading: After pushing in the load to 15 μN at a pushing speed of 1.5 μN / second, it is held for 5 seconds at the maximum load and then unloaded at a speed of 1.5 μN / second. · Measurement location: Using the shape measurement function of the measurement device that scans the sample surface with the indenter, an image of the shape of the sample surface is obtained, and 20 points are specified at intervals of 1 μm or more on the sample surface from the shape image. When calculating the hardness, fused quartz is used as a standard sample, and the relationship between the contact depth and the contact projected area of the indenter and the sample is calibrated in advance. Then, the unloading curve in the range of 60 to 95% of the maximum load during unloading is analyzed by the Oliver-Pharr method to calculate the hardness.

[0061] The coating layer 50 may be a gas barrier coating layer. In this case, the gas barrier property of the packaging film 100 is improved. Further, even if cracks or other damages occur in the vapor deposition layer 40, a decrease in the gas barrier property of the packaging film 100 can be suppressed.

[0062] The gas barrier coating layer is composed of, for example, a cured product of a composition containing a water-soluble polymer and at least one of a metal alkoxide and its hydrolyzate. The above composition may further contain at least one of a silane coupling agent and its hydrolyzate.

[0063] Examples of the water-soluble polymer include polyvinyl alcohol, polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate, and the like. Among these, polyvinyl alcohol (PVA) is particularly preferable because it easily improves the oxygen barrier property of the gas barrier film.

[0064] Examples of the metal alkoxide include compounds represented by the following general formula (1). M(OR 11 ) m (R 12 ) n-m ···(1) In the above formula (1), R 11 is a monovalent organic group having 1 to 8 carbon atoms, and may be an alkyl group such as a methyl group or an ethyl group (OR 11 is a hydrolyzable group). R 12 is a monovalent organic group having 1 to 8 carbon atoms, and may be an alkyl group such as a methyl group or an ethyl group. M represents an n-valent metal atom such as Si, Ti, Al, or Zr. m is an integer from 1 to n. When there are a plurality of R 11 and R 12 , R 11 to each other or R12 They may be the same or different from each other.

[0065] Specific examples of the metal alkoxide include tetraethoxysilane [Si(OC2H5)4], triisopropoxyaluminum [Al(O-2’-C3H7)3], etc. Tetraethoxysilane (TEOS) and triisopropoxyaluminum are preferred because they are relatively stable in an aqueous solvent after hydrolysis.

[0066] Examples of the silane coupling agent include compounds represented by the following general formula (2). (R 2 Si(OR 3 )3) n ······(2) In the above general formula (2), R 2 represents a monovalent organic group, and R 3 represents an alkyl group or -C2H4OCH3. In this case, it becomes possible to improve the adhesion between the gas barrier coating layer and the vapor deposition layer 40, and delamination in the packaging film 100 can be suppressed. Note that R 2 and R 3 may be the same or different from each other. R 3 themselves may be the same or different from each other. Examples of the monovalent organic group represented by R 2 include a monovalent organic functional group containing a vinyl group, an epoxy group, a mercapto group, an amino group, or an isocyanate group. Among them, as the monovalent organic functional group, an isocyanate group is preferred. In this case, the composition can have more excellent hot water resistance by curing, and it becomes possible to impart a greater laminate strength even after a wet heat treatment such as a retort treatment or a boiling treatment to the packaging film 100. Examples of the alkyl group represented by R 3 include, for example, a methyl group, an ethyl group, etc. Among them, a methyl group is preferred. In this case, hydrolysis proceeds quickly. n represents an integer of 1 or more. When n is 1, the silane coupling agent represents a monomer, while when n is 2 or more, the silane coupling agent represents a polymer. Preferably, n is 3. In this case, the hot water resistance of the gas barrier coating layer can be further improved, and it becomes possible to impart a greater laminate strength even after a wet heat treatment such as retort treatment or boiling treatment to the gas barrier coating layer.

[0067] Specific examples of the silane coupling agent include silane coupling agents such as vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, 1,3,5-tris(3-methoxysilylpropyl)isocyanurate.

[0068] When the above composition contains PVA as a water-soluble polymer, the amount of PVA in the composition may be 15% by mass or more, 20% by mass or more, or 25% by mass or more based on the total solid content of the composition from the viewpoint of maintaining the flexibility of the gas barrier coating layer and facilitating the formation of the gas barrier coating layer. When the composition contains PVA as a water-soluble polymer, the amount of PVA in the composition may be 70% by mass or less, 60% by mass or less, or 50% by mass or less based on the total solid content of the composition from the viewpoint of easily maintaining a low oxygen permeability even after heat sterilization treatment.

[0069] When the composition contains TEOS (tetraethoxysilane) as a metal alkoxide, the amount of TEOS in the composition may be 30% by mass or more, 35% by mass or more, or 40% by mass or more based on the total solid content of the composition, from the viewpoint of easily maintaining a low oxygen permeability even after heat sterilization treatment. When the composition contains TEOS as a metal alkoxide, the amount of TEOS in the composition may be 80% by mass or less, 75% by mass or less, or 70% by mass or less based on the total solid content of the composition, from the viewpoint of retaining the flexibility of the gas barrier coating layer and facilitating the formation of the gas barrier coating layer. In this specification, the amount of TEOS means the value in terms of SiO2.

[0070] When the composition contains isocyanurate silane as a silane coupling agent, the amount of isocyanurate silane in the composition may be 1% by mass or more, 3% by mass or more, or 5% by mass or more based on the total solid content of the composition, from the viewpoint of easily realizing heat resistance to water and easily realizing excellent adhesion even after heat sterilization treatment. When the composition contains isocyanurate silane as a silane coupling agent, the amount of isocyanurate silane in the composition may be 20% by mass or less, 15% by mass or less, or 10% by mass or less based on the total solid content of the composition, from the viewpoint of not causing the amount of other components in the composition to be too small and easily maintaining a low oxygen permeability even after heat sterilization treatment.

[0071] The gas barrier coating layer can be formed by coating the composition for forming the gas barrier coating layer on the vapor deposition layer 40 and then drying it by heating. The composition for forming the gas barrier coating layer can be prepared by dissolving a water-soluble polymer in an aqueous solvent (such as water, a mixed solvent of water and alcohol, etc.) and mixing at least one of a metal alkoxide and a silane coupling agent, or a hydrolyzed product thereof in advance. Known additives such as isocyanate compounds; dispersants, stabilizers, viscosity modifiers, colorants, etc. can also be added to this composition (mixed solution).

[0072] When forming the gas barrier coating layer, the drying temperature may be, for example, 40°C or higher, 60°C or higher, or 90°C or higher, and may also be 140°C or lower, 130°C or lower, or 120°C or lower.

[0073] The thickness of the gas barrier coating layer may be 80 nm or more, 90 nm or more, or 100 nm or more. If the thickness of the gas barrier coating layer is 80 nm or more, it is easy to maintain a low oxygen permeability even after heat sterilization treatment. The thickness of the gas barrier coating layer may be 1000 nm or less, 700 nm or less, 500 nm or less, or 400 nm or less. If the thickness of the gas barrier coating layer is 1000 nm or less, it is possible to suppress a decrease in gas barrier properties due to the generation of cracks in the gas barrier coating layer during coating. From such a viewpoint, the thickness of the gas barrier coating layer may be 80 to 1000 nm.

[0074] (Printing layer) As described above, the gas barrier film 10 may further have a printing layer as necessary. The printing layer can be provided on at least one of the base material layer 20 and the coating layer 50. The printing layer is a layer formed using an ink obtained by adding various pigments, plasticizers, desiccants, stabilizers, etc. to a binder resin such as a urethane-based, acrylic-based, nitrocellulose-based, or rubber-based resin. Characters, patterns, symbols, and combinations thereof can be displayed by this printing layer.

[0075] The ink may be aqueous ink or oil-based ink, but aqueous ink is preferred. Since aqueous ink uses water or alcohol as a solvent, the environmental load can be further reduced. Also, the ink may or may not be biomass ink, but from the viewpoint of reducing the environmental load, it is preferably biomass ink. Here, biomass ink refers to ink containing components obtained from biological resources (biomass) such as cotton, pulp, rice bran, vegetable oil, and seeds of angiosperms. Examples of methods for forming the printing layer include conventionally known printing methods such as gravure printing, offset printing, and flexographic printing.

[0076] (2) Adhesive layer The adhesive layer 60 is a layer obtained by melt-extruding and laminating an adhesive resin composition containing a polyolefin-based adhesive resin onto the gas barrier film 10. Examples of the polyolefin-based adhesive resin include acid-modified polypropylene-based resins and acid-modified polyethylene-based resins.

[0077] Examples of the acid-modified polypropylene-based resin include maleic anhydride graft-modified polypropylene-based resins. The maleic anhydride graft-modified polypropylene-based resin is a resin obtained by graft-modifying a polypropylene-based resin with maleic anhydride. The graft ratio of maleic anhydride is preferably 0.1 to 1% by mass. When the graft ratio of maleic anhydride is 0.1% by mass or more, the adhesiveness of the adhesive layer 60 is further improved. When the graft ratio of maleic anhydride is 1% by mass or less, it becomes difficult to adsorb moisture and foaming is less likely to occur. Also, the processability of the adhesive resin composition is improved.

[0078] Examples of the polypropylene-based resin include homopolypropylene, block polypropylene, random polypropylene, and propylene-α-olefin copolymers. Examples of the α-olefin include ethylene and 1-butene.

[0079] Examples of the acid-modified polyethylene-based resin include maleic anhydride graft-modified polyethylene-based resins. The maleic anhydride graft-modified polyethylene resin is a resin obtained by graft-modifying a polyethylene resin with maleic anhydride. The grafting rate of maleic anhydride is preferably 0.1 to 1% by mass. When the grafting rate of maleic anhydride is 0.1% by mass or more, the adhesiveness of the adhesive layer 60 is further improved. When the grafting rate of maleic anhydride is 1% by mass or less, it becomes difficult to adsorb moisture and foaming is less likely to occur. Also, the processability of the adhesive resin composition is improved. Examples of the polyethylene resin include high-density polyethylene, medium-density polyethylene, low-density polyethylene, and linear low-density polyethylene obtained by copolymerizing ethylene and an α-olefin. Examples of the α-olefin include ethylene, 1-butene, and 1-hexane.

[0080] The adhesive layer 60 is obtained by melt-extruding and laminating an adhesive resin composition onto the gas barrier film 10. After the adhesive resin composition comes into contact with the coating layer 50 of the gas barrier film 10, it is cooled by a cooling roll.

[0081] The thickness of the adhesive layer 60 is not particularly limited, but is preferably 1 μm or more, and more preferably 5 μm or more. When the thickness of the adhesive layer 60 is 1 μm or more, the adhesiveness between the gas barrier film 10 and the sealant layer 70 is effectively improved. The thickness of the adhesive layer 60 may be 40 μm or less, or 15 μm or less.

[0082] The adhesive layer 60 is preferably obtained by heat-treating the adhesive resin composition. In this case, the adhesive strength of the adhesive layer 60 can be improved, and the heat and moisture resistance such as heat sealability, impact resistance, retort treatment, boiling treatment, and humidity conditioning treatment of the packaging film 100 can be improved. The heat treatment can be performed by forming a layer made of the adhesive resin composition and applying heat to this layer through a heater roll or an oven. This heat treatment can be performed, for example, in a state where the gas barrier film 10 and the sealant layer 70 are laminated via the adhesive resin composition.

[0083] (3) Sealant layer The sealant layer 70 contains a polyolefin resin. Examples of the polyolefin resin include polyethylene resins and polypropylene resins. Examples of the polyethylene resin include low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), linear low-density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, ethylene-(meth)acrylic acid copolymer, and the like. Examples of the polypropylene resin include homopolypropylene, block polypropylene, random polypropylene, and propylene-α-olefin copolymer. Examples of α-olefin include ethylene, 1-butene, and the like. Among these, from the viewpoint of heat resistance, polypropylene resins are preferred. Furthermore, among the polypropylene resins, when emphasizing the rigidity and heat resistance of the packaging bag obtained using the packaging film 100, it is preferable to use homopolypropylene. Also, the polyolefin resin may be a biomass-derived polyolefin resin or a mechanically recycled or chemically recycled polyolefin resin. The sealant layer 70 may have a single-layer structure or a multilayer structure.

[0084] The sealant layer 70 may contain additives as required. Examples of the additives include crosslinking agents, antioxidants, antiblocking agents, slip agents, ultraviolet absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

[0085] When the polyolefin resin contained in the polyolefin-based substrate layer 21 of the substrate layer 20 and the polyolefin-based adhesive resin contained in the adhesive layer 60 are polypropylene-based resins, the polyolefin resin contained in the sealant layer 70 is preferably a polypropylene-based resin. In this case, the ratio of the single material (polypropylene-based resin) contained in the packaging film 100 can be increased, and the recyclability of the packaging film 100 is further improved. Alternatively, when the polyolefin resin contained in the polyolefin-based substrate layer 21 of the substrate layer 20 and the polyolefin-based adhesive resin contained in the adhesive layer 60 are polyethylene-based resins, the polyolefin resin contained in the sealant layer 70 is preferably a polyethylene-based resin. In this case, the ratio of the single material (polyethylene-based resin) contained in the packaging film 100 can be increased, and the recyclability of the packaging film 100 is further improved.

[0086] The polyolefin resin contained in the sealant layer 70 may be a stretched film or an unstretched film, but an unstretched film (for example, CPP) is preferred. In this case, the melting point of the sealant layer 70 can be lowered, and it is easier to suppress the melting of the substrate layer 20 during heat sealing of the packaging film 100.

[0087] The thickness of the sealant layer 70 is not particularly limited, but from the viewpoint of improving heat sealability, it is preferably 40 μm or more, and more preferably 50 μm or more. From the viewpoint of improving the flexibility of the packaging film 100, the thickness of the sealant layer 70 is preferably 100 μm or less, and more preferably 80 μm or less.

[0088] The sealant layer 70 can be formed by attaching it to the adhesive layer 60 by melt extrusion. At this time, the sealant layer 70 may be formed by melt-extruding a resin composition for forming the sealant layer that forms the sealant layer 70 and attaching it to the adhesive layer 60, or by co-extruding an adhesive resin composition and a resin composition for forming the sealant layer that forms the sealant layer 70 and attaching it to the adhesive layer 60 with the adhesive resin composition facing the adhesive layer 60 side. Alternatively, the sealant layer 70 may be formed simultaneously with the adhesive layer 60 by co-extruding an adhesive resin composition for forming the adhesive layer 60 and a resin composition for forming the sealant layer that forms the sealant layer 70.

[0089] <Packaging product> Next, an embodiment of the packaging product of the present disclosure will be described with reference to FIG. 2. Note that FIG. 2 is a cross-sectional view showing an embodiment of the packaging product of the present disclosure. In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and redundant descriptions are omitted. As shown in FIG. 2, the packaging product 300 includes a packaging bag 200 and contents C accommodated in the packaging bag 200. The packaging bag 200 shown in FIG. 2 is obtained by using a pair of packaging films 100 and heat-sealing the peripheral portions of the packaging films 100 with the sealant layers 70 facing each other.

[0090] This packaging product 300 includes a packaging bag 200. According to the packaging bag 200, it is possible to have excellent gas barrier properties while suppressing a decrease in the ratio of the polyolefin-based resin in the entire packaging bag 200. Therefore, according to the packaging product 300, recycling after opening can be easily performed, and deterioration of the quality of the contents C can also be suppressed.

[0091] Note that the packaging bag 200 can also be obtained by folding one packaging film 100 and heat-sealing the peripheral portions of the packaging film 100 with the sealant layers 70 facing each other.

[0092] Examples of the packaging bag 200 include a three-side pouch, a four-side pouch, a standing pouch, a gusset pouch, a pillow package, etc. The packaging bag 200 may further have a spout or a chuck according to the use.

[0093] The content C is not particularly limited, and examples of the content C include food, liquid, pharmaceuticals, electronic components, etc.

[0094] <Summary of the present disclosure> The summary of the present disclosure is as follows. [1] A packaging film comprising a gas barrier film, an adhesive layer, and a sealant layer in this order, wherein the gas barrier film has a base material layer and a vapor deposition layer, the base material layer has a polyolefin-based base material layer containing a polyolefin-based resin and a heat-resistant layer, the heat-resistant layer contains a high melting point resin having a melting point of 180 °C or higher, the adhesive layer is obtained by melt-extruding and laminating an adhesive resin composition containing a polyolefin-based adhesive resin onto the gas barrier film, and the sealant layer contains a polyolefin-based resin. [2] The packaging film according to [1], wherein the heat-resistant layer is provided on the vapor deposition layer side of the polyolefin-based base material layer. [3] The packaging film according to [1] or [2], wherein the polyolefin-based base material layer is a stretched film. [4] The packaging film according to any one of [1] to [3], wherein the high melting point resin of the heat-resistant layer contains a polyamide resin. [5] The packaging film according to any one of [1] to [4], wherein the heat-resistant layer contains a high melting point resin having a melting point of 185 °C or higher. [6] The packaging film according to any one of [1] to [5], wherein the ratio of the thickness of the heat-resistant layer to the thickness of the gas barrier film is 50% or less. [7] The packaging film according to any one of [1] to [6], wherein the gas barrier film further includes an anchor coat layer containing a polyurethane resin between the vapor deposition layer and the base material layer. [8] The packaging film according to any one of [1] to [7], wherein the gas barrier film further comprises a coating layer that coats the vapor deposition layer between the vapor deposition layer and the polyolefin-based adhesive resin layer. [9] A packaging bag comprising the packaging film according to any one of [1] to [8].

[10] A packaging product comprising the packaging bag according to [9] and the contents accommodated in the packaging bag.

Example

[0095] Hereinafter, the present disclosure will be specifically described with reference to examples, but the present disclosure is not limited to these examples.

[0096] <Preparation of coating solution> Coating solutions 1 to 2 as compositions for forming a gas barrier coating layer used in the examples or comparative examples were prepared as follows.

[0097] (Coating solution 1) The following liquids A to C were mixed to obtain coating solution 1. When the solid content was set to 100, coating solution 1 was prepared so that the mass ratio of TEOS (SiO2 conversion value), PVA, and isocyanurate silane (R 2 Si(OH)3 conversion value) was 68 / 27 / 5. Liquid A: Tetraethoxysilane (trade name: KBE04, solid content: 100% by mass, manufactured by Shin-Etsu Chemical Co., Ltd., also referred to as "TEOS"), methanol (manufactured by Kanto Chemical Co., Inc.), and 0.1N hydrochloric acid (manufactured by Kanto Chemical Co., Inc.) were mixed at a mass ratio of 17:10:73, and the resulting mixed solution was stirred for 30 minutes to hydrolyze TEOS (5% by mass (SiO2 conversion) hydrolysis solution of TEOS). Liquid B: A 5% by mass aqueous solution of polyvinyl alcohol (trade name: Kuraray Poval 60-98, manufactured by Kuraray Co., Ltd., also referred to as "PVA"). Liquid C: 1,3,5-Tris(3-methoxysilylpropyl) isocyanurate (trade name: X-12-965P, manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent (SC agent) was used in a mixed solution of water / IPA = 1 / 1 (mass ratio) with a solid content ratio of 5% (R2 A solution diluted so as to be converted to Si(OH)3. (Coating liquid 2) The above A to C liquids were mixed to obtain coating liquid 2. When the solid content was set to 100, coating liquid 2 was prepared so that the mass ratio of TEOS (SiO2 conversion value), PVA, and isocyanurate silane (R 2 Si(OH)3 conversion value) was 47.6 / 47.6 / 4.8. (Coating liquid 3) The above A to C liquids were mixed to obtain coating liquid 3. When the solid content was set to 100, coating liquid 3 was prepared so that the mass ratio of TEOS (SiO2 conversion value), PVA, and isocyanurate silane (R 2 Si(OH)3 conversion value) was 85 / 10.2 / 4.8.

[0098] >[Preparation of Anchor Coating Layer Forming Composition]< The anchor coating layer forming composition was prepared as follows. Acrylic polyol and tolylene diisocyanate were mixed so that the number of NCO groups of tolylene diisocyanate was equal to the number of OH groups of acrylic polyol, and diluted with ethyl acetate so that the solid content (total amount of acrylic polyol and tolylene diisocyanate) was 5% by mass. To the diluted mixture, β-(3,4-epoxycyclohexyl)trimethoxysilane was added in an amount of 5 parts by mass with respect to 100 parts by mass of the total amount of acrylic polyol and tolylene diisocyanate, and these were mixed to prepare an anchor coating layer forming composition (anchor coating agent).

[0099] >[Production of Packaging Film]< (Example 1) First, homopolypropylene as a polyolefin-based substrate layer (PO-based substrate layer) (hereinafter also referred to as "PP1". Melting point: 162 °C, density: 0.9 g / cm 3 , MFR (230 °C, load 2.16 kg): 3.0 g / 10 min) and maleic acid-modified polypropylene as a substrate adhesive layer (hereinafter also referred to as "PP1". Melting point: 165 °C, density: 0.89 g / cm 3, MFR (230 °C, load 2.16 kg): 6.5 g / 10 min), and nylon 6 as the heat-resistant layer (hereinafter also referred to as "Ny". Melting point: 225 °C, density: 1.1 g / cm 3 , MVR (275 °C, load 5.0 kg): 70 cm 3 / 10 min) were co-extruded using a co-extrusion film forming machine so as to have thicknesses of 10 μm, 5 μm, and 5 μm as shown in Table 1 respectively, and the base material was formed by performing a biaxial stretching treatment. At this time, the temperature of each layer confluence part was set to 260 °C. Next, corona treatment was performed on the surface of the base material as a surface treatment to obtain a base material layer. Next, on the surface of the base material layer, using an electron beam heating type vacuum evaporation apparatus, SiO having a thickness of 0.020 μm x The film was formed as a vapor deposition layer. Next, coating liquid 3 was applied on the vapor deposition layer to form a coating film. The formed coating film was dried by heating at 80 °C for 60 seconds to form a gas barrier coating layer having a thickness of 0.32 μm as a coating layer. Next, white ink was solidly printed with a thickness of 1 μm on the gas barrier coating layer by the gravure method to form a printing layer. Thus, a gas barrier film was obtained. Next, on the printing layer of the above gas barrier film, maleic anhydride-modified PP (hereinafter also referred to as "PP2". Melting point: 106 °C, density: 0.89 g / cm 3 , MFR (230 °C, load 2.16 kg): 12 g / 10 min) was laminated by melt extrusion at a molding temperature of 250 °C so as to have a thickness of 20 μm. Subsequently, on the adhesive layer, using the T-die casting method, a sealant layer made of block PP (melting point: 160 °C, density: 0.90 g / cm 3 , MFR (230 °C, load 2.16 kg): 2.5 g / 10 min) was discharged at a discharge temperature of 250 °C so as to have a thickness of 40 μm to obtain a laminate. Then, the above laminate was heated and pressure-bonded for 40 seconds with a roll heated to 140 °C. A packaging film was obtained as described above.

[0100] (Examples 2 to 3) A packaging film was obtained in the same manner as in Example 1, except that the base material layer was formed such that the PO-based base material layer, the base material adhesive layer, and the heat-resistant layer each had the thickness shown in Table 1.

[0101] (Example 4) A packaging film was obtained in the same manner as in Example 1, except that the heat-resistant layer constituting the base material layer was changed from Ny to EVOH (trade name "F171B", manufactured by Kuraray Co., Ltd., melting point: 183°C, ethylene content: 32 mol%).

[0102] (Comparative Example 1) A packaging film was obtained in the same manner as in Example 1, except that the base material layer was composed only of a PO-based base material layer having the thickness shown in Table 1.

[0103] (Example 5) A gas barrier film was produced in the same manner as in Example 1, except that the vapor deposition layer was an AlO layer having the thickness shown in Table 2. x Subsequently, maleic anhydride-modified PP (melting point: 106°C, density: 0.89 g / cm, MFR (230°C, load 2.16 kg): 12 g / 10 min) was melt-extruded at a molding temperature of 250°C so as to have the thickness shown in Table 2 on the printing layer of the above gas barrier film to form an adhesive layer. Subsequently, a CPP film (trade name "Trefan ZK207", manufactured by Toray Film Processing Co., Ltd., thickness: 40 μm) was laminated as a sealant layer on the adhesive layer using a T-die casting method to obtain a laminate. Then, the above laminate was heat-pressed for 15 seconds with a roll heated to 140°C. 3 A packaging film was obtained as described above. Subsequently, the above laminate was heat-pressed for 15 seconds with a roll heated to 140°C. A packaging film was obtained as described above.

[0104] (Example 6) A gas barrier film was produced in the same manner as in Example 1, except that the gas barrier coating layer was formed using Coating Liquid 2 as shown in Table 2. Next, an adhesive layer and a sealant layer were formed on the printing layer of the gas barrier film in the same manner as in Example 5 to obtain a packaging film.

[0105] (Examples 7 and 8) A base material layer was produced in the same manner as in Example 1, except that the heat-resistant layer was not surface-treated. On the heat-resistant layer of this base material layer, the composition for forming an anchor coat layer prepared as described above was applied by a gravure coating method so as to have the thickness shown in Table 2 after drying to form a coating film. Then, the coating film was heated at 120 °C for 10 seconds and dried to form an anchor coat layer containing a polyurethane-based resin (PU). Then, a vapor deposition layer, a coating layer, and a printing layer were formed on the anchor coat layer in the same manner as in Example 6 to obtain a gas barrier film. Next, an adhesive layer and a sealant layer were formed on the printing layer of the gas barrier film in the same manner as in Example 6 to obtain a packaging film.

[0106] (Example 9) First, a gas barrier film was produced in the same manner as in Example 1. Next, on the printing layer of the gas barrier film, using a coextrusion method, an adhesive layer made of PP2 and a sealant layer made of block PP (melting point: 160 °C, density: 0.90 g / cm 3 , MFR (230 °C, load 2.16 kg): 2.5 g / 10 min) were discharged at a discharge temperature of 250 °C so that the thickness of each layer was 5 μm and 55 μm, and laminated so that the adhesive layer was in contact with the printing layer to obtain a laminate. Then, the laminate was heat-pressed for 15 seconds with a roll heated to 140 °C. A packaging film was obtained as described above.

[0107] (Example 10) When forming the base material layer, as the PO-based base material layer, polyethylene (melting point: 127 °C, density: 0.938 g / cm 3, using MFR (190 °C, load 2.16 kg): 3.8 g / 10 min), as the base material adhesive layer, polyethylene (melting point: 120 °C, density: 0.91 g / cm 3 , an adhesive resin (hereinafter also referred to as "PE1") having MFR (190 °C, load 2.16 kg): 2.2 g / 10 min) was used, and a gas barrier film was produced in the same manner as in Example 1 except for this. Next, on the printing layer of the above gas barrier film, as an adhesive layer, modified polyethylene (melting point: 120 °C, density: 0.910 g / cm 3 , an adhesive resin (hereinafter also referred to as "PE2") having MFR (190 °C, load 2.16 kg): 2.2 g / 10 min) was melt-extruded at a molding temperature of 260 °C so as to have the thickness shown in Table 2 and laminated. Subsequently, an LLDPE film (trade name "SE625N", manufactured by Tamapoly Co., Ltd., thickness: 40 μm) was laminated as a sealant layer on the adhesive layer to obtain a laminate. Thereafter, the above laminate was heat-pressed for 40 seconds with a roll heated to 140 °C. A packaging film was obtained as described above.

[0108] (Examples 11 and 12) A packaging film was obtained in the same manner as in Example 10 except that the base material layer was formed such that the PO-based base material layer, the base material adhesive layer, and the heat-resistant layer each had the thickness shown in Table 3.

[0109] (Examples 13 and 14) A base material layer was produced in the same manner as in Example 10 except that the heat-resistant layer was not surface-treated. On the heat-resistant layer of this base material layer, the composition for forming an anchor coat layer prepared as described above was applied by a gravure coating method so as to have the thickness shown in Table 3 after drying to form a coating film. Then, the coating film was heated at 120 °C for 10 seconds and dried to form an anchor coat layer containing a polyurethane-based resin (PU). Then, on the anchor coat layer, a vapor deposition layer, a coating layer, and a printing layer were formed in the same manner as in Example 10 to obtain a gas barrier film. Next, an adhesive layer and a sealant layer were formed in the same manner as in Example 10 on the printing layer of the gas barrier film, to obtain a packaging film.

[0110] (Example 15) A gas barrier film was produced in the same manner as in Example 10. Next, an adhesive layer made of adhesive polyethylene (melting point: 120°C, density: 0.910 g / cm 3 , MFR (190°C, load 2.16 kg): 2.2 g / 10 min) and a sealant layer made of LLDPE (trade name "SE625N", manufactured by Tamapoly Co., Ltd.) were extruded at a discharge temperature of 260°C so that the thickness of each layer was 5 μm and 55 μm, and laminated so that the adhesive layer was in contact with the printing layer, to obtain a laminate. Then, the above laminate was heat-pressed for 15 seconds with a roll heated to 140°C. A packaging film was obtained as described above.

[0111] (Example 16) A gas barrier film was produced in the same manner as in Example 1. Next, an adhesive layer and a sealant layer were formed in the same manner as in Example 10 on the printing layer of the gas barrier film, to obtain a packaging film.

[0112] <Hardness in the cross-section of the coating layer> The hardness in the cross-section of the coating layer of the packaging film obtained in the example or comparative example was measured as follows by the nanoindentation method. The measurement sample (cross-section sample) was prepared as follows. That is, after corona treatment was performed on both sides of the packaging film, it was embedded in a visible light curable resin (Aronix LCR D-800, manufactured by Toagosei Co., Ltd.). Then, using an ultramicrotome Leica EM UC7 and a diamond knife Microstar LH, the packaging film was cut perpendicular to the lamination direction. The exposed cross-section was finish-treated under the conditions of a cutting thickness Feed of 200 nm and a cutting speed Speed of 1 mm / s to obtain a measurement sample. For the measurement, Hysitron TI-Premier (trade name) manufactured by Bruker Japan Co., Ltd. was used as the measuring device, and a Berkovich-type diamond indenter manufactured by Bruker Japan Co., Ltd. was used as the indenter. The measurement conditions were as follows. · Temperature: room temperature (25 °C) · Mode: load control mode · Press-in and unloading: After pressing in to a load of 15 μN at a pressing-in speed of 1.5 μN / second, it was held for 5 seconds at the maximum load, and then unloaded at a speed of 1.5 μN / second. · Measurement location: Using the shape measurement function of the measuring device that scans the sample surface with the indenter, the shape image of the coating layer cross-section was obtained, and 20 points were specified at intervals of 1 μm or more on the coating layer cross-section from the shape image. When calculating the hardness, fused quartz was used as the standard sample, and the relationship between the contact depth and the contact projected area between the indenter and the sample was calibrated in advance. Then, the unloading curve in the 60 - 95% region with respect to the maximum load during unloading was analyzed by the Oliver-Pharr method to calculate the hardness of the coating layer cross-section. The results are shown in Tables 1 - 3. In Tables 1 - 3, the hardness of the coating layer cross-section is shown in parentheses under the coating liquid used for forming the coating layer.

[0113] <Evaluation of Packaging Film> (1) Gas barrier property (Before retort treatment or before boiling treatment) First, test pieces of 100 mm × 100 mm were cut from the packaging films of Examples 1 - 16 and Comparative Example 1. For these test pieces, an oxygen permeability measuring device (product name "OX-TRAN2 / 20", manufactured by MOCON) was used to measure the oxygen permeability (unit: cc / m 2 · day·atm) under the conditions of a temperature of 30 °C and a relative humidity of 70%. At this time, the measurement was carried out in accordance with JIS K-7126-2. The results are shown in Tables 1 - 3.

[0114] (After retort treatment) The packaging films of Examples 1 to 3, 5 to 9 and Comparative Example 1 were cut into pieces of 297 mm × 210 mm, and using the cut packaging films, three-side pouches having openings were produced. At this time, the three-side pouches were formed by bending the cut packaging films so that the sealant layers faced each other and heat-sealing the peripheral portions of the sealant layers together. Then, tap water (municipal water) was injected from the opening and the opening of the three-side pouch was sealed to prepare a sealed pouch. Then, this sealed pouch was subjected to retort treatment at 130°C for 30 minutes using a retort apparatus for storing hot water. Thereafter, a test piece of 100 mm × 100 mm was cut out from the sealed body after the retort treatment, and for this test piece, the oxygen permeability (unit: cc / m 2 ·day·atm) was measured in the same manner as before the retort treatment. The results are shown in Tables 1 to 2.

[0115] (After boiling treatment) The packaging films of Examples 10 to 16 were cut into pieces of 297 mm × 210 mm, and using the cut packaging films, three-side pouches having openings were produced. At this time, the three-side pouches were formed by bending the cut packaging films so that the sealant layers faced each other and heat-sealing the peripheral portions of the sealant layers together. Then, tap water (municipal water) was injected from the opening and the opening of the three-side pouch was sealed to prepare a sealed pouch. Then, this sealed pouch was subjected to boiling treatment at 95°C for 30 minutes using a boiling treatment apparatus. Thereafter, a test piece of 100 mm × 100 mm was cut out from the sealed body after the boiling treatment, and for this test piece, the oxygen permeability (unit: cc / m 2 ·day·atm) was measured in the same manner as before the boiling treatment. The results are shown in Tables 2 to 3.

[0116] (2) Ratio of polyolefin resin in the whole packaging film For the packaging films of Examples 1 to 16 and Comparative Example 1, the ratio (mass%) of the polyolefin resin in the whole packaging film was calculated by converting the specific gravity from the weight of the packaging film. The results are shown in Tables 1 to 3.

[0117]

Table 1

[0118]

Table 2

[0119]

Table 3

[0120] From the results shown in Tables 1 to 3, it was found that all of the packaging films of the examples had a high polyolefin resin ratio of 90% by mass or more in the entire packaging film and a sufficiently low oxygen permeability before retort treatment. Therefore, it was confirmed that the packaging film of the present disclosure has excellent gas barrier properties while suppressing a decrease in the ratio of the polyolefin resin in the entire packaging film.

Description of Reference Numerals

[0121] 10... gas barrier film, 20... base material layer, 21... polyolefin base material layer, 22... heat resistant layer, 30... anchor coat layer, 40... vapor deposition layer, 50... coating layer, 60... adhesive layer, 70... sealant layer, 100... packaging film, 200... packaging bag, 300... packaged product, C... contents.

Claims

1. A gas barrier film, an adhesive layer, and a sealant layer are provided in this order, the gas barrier film has a base layer and a deposition layer, the substrate layer has a polyolefin substrate layer containing a polyolefin resin and a heat-resistant layer, The heat-resistant layer contains a high-melting-point resin having a melting point of 180° C. or higher, the adhesive layer is obtained by bonding an adhesive resin composition containing a polyolefin-based adhesive resin to the gas barrier film by melt extrusion, The packaging film, wherein the sealant layer comprises a polyolefin resin.

2. The packaging film according to claim 1 , wherein the heat-resistant layer is provided on the vapor-deposited layer side of the polyolefin-based substrate layer.

3. The packaging film according to claim 1 , wherein the polyolefin-based substrate layer is a stretched film.

4. The packaging film according to claim 1 , wherein the high melting point resin of the heat-resistant layer comprises a polyamide resin.

5. The packaging film according to claim 1 , wherein the heat-resistant layer comprises a high melting point resin having a melting point of 185° C. or higher.

6. The packaging film according to claim 1 , wherein the ratio of the thickness of the heat-resistant layer to the thickness of the gas barrier film is 50% or less.

7. The packaging film according to claim 1 , wherein the gas barrier film further comprises an anchor coat layer containing a polyurethane resin between the deposition layer and the base layer.

8. The packaging film according to claim 1 , wherein the gas barrier film further comprises a coating layer between the vapor deposition layer and the polyolefin-based adhesive resin layer, the coating layer coating the vapor deposition layer.

9. A packaging bag comprising the packaging film according to any one of claims 1 to 8.

10. A packaging product comprising the packaging bag according to claim 9 and contents contained within the packaging bag.

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