Packaging films, packaging bags and food packaging

Abstract

To provide a packaging film capable of suppressing a deterioration in appearance of a food packaging body, when forming a packaging bag and accommodating, inside the packaging bag, a food product having a surface layer part composed of a lipid-containing product containing 40 mass% or more lipid to form the food packaging body, and also to provide the packaging bag and the food packaging body.SOLUTION: A packaging film is to be used for packaging a food product having a surface layer part composed of a lipid-containing product containing 40 mass% or more lipid. The packaging film includes a sealant layer having a first resin layer. The first resin layer includes a food product-opposing surface to oppose a food product. The first resin layer contains (A) a polyolefin resin and (B) a silylated polyolefin.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a packaging film, a packaging bag, and a food package. [Background technology]

[0002] Packaging films for packaging foods such as butter have been known for some time. For example, the following Patent Document 1 discloses a laminated packaging material as a packaging film, which is formed by laminating a polyethylene film made of a mixture of 100 parts by weight of linear low-density polyethylene and 5 to 40 parts by weight of low-density polyethylene onto a base layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-187962 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the packaging film described in Patent Document 1 has the following problems.

[0005] That is, when the packaging film described in Patent Document 1 is transparent, a packaging bag is formed using this packaging film, and a food is placed inside the packaging bag to form a food package, and the food can be seen from the outside of the packaging bag. In this case, if the food has a surface layer made of a lipid-containing product containing 40% or more by mass of lipid, the lipid-containing product is likely to adhere to the inner surface of the food package, and the adhered lipid-containing product may deteriorate the appearance of the food package. Such deterioration in the appearance of the food package may lead to a decrease in the willingness of consumers to purchase the food.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a packaging film, a packaging bag, and a food package that can suppress deterioration in the appearance of a food package when a packaging bag is formed and a food having a surface layer composed of a lipid-containing product containing 40% or more by mass of lipids is placed inside the packaging bag to form a food package. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, the present invention provides a packaging film used for packaging food having a surface portion composed of a lipid-containing product containing 40% or more by mass of lipid, the packaging film comprising a sealant layer having a first resin layer, the first resin layer having a food-facing surface for facing the food, and the first resin layer containing (A) a polyolefin resin and (B) a silylated polyolefin.

[0008] According to the packaging film of the present invention, the first resin layer of the sealant layer contains (A) a polyolefin resin and (B) a silylated polyolefin, so that the lipid-containing product of a food having a surface layer portion composed of a lipid-containing product containing 40% by mass or more of lipids is less likely to adhere to the food-facing surface of the first resin layer. Therefore, when a packaging bag is formed using this packaging film and the food is placed in the packaging bag to form a food package, deterioration of the appearance of the food package can be suppressed.

[0009] In the packaging film, it is preferable that the sealant layer further has a second resin layer on the side opposite to the food-facing surface of the first resin layer.

[0010] In this case, the fat-containing food product can be made less likely to adhere to the food-facing surface of the first resin layer, and the deterioration of the appearance of the food package tends to be more suppressed. In addition, since the sealant layer further includes the second resin layer, the packaging film can have further functionality (heat resistance, impact resistance, etc.). In addition, the first resin layer can be made thinner, which also allows the cost of the packaging film to be reduced.

[0011] It is preferable that the packaging film further has a base layer provided on the sealant layer, and the base layer is arranged on the opposite side of the sealant layer to the food-facing surface of the first resin layer.

[0012] In this case, the sealant layer is reinforced by the base layer, improving the mechanical strength of the packaging film. Furthermore, the presence of the base layer in the packaging film allows it to have functions such as barrier properties and light-shielding properties.

[0013] The packaging film preferably has a stiffness value of 5 to 55 mN in a loop stiffness measurement with a loop length of 85 mm.

[0014] In this case, the pressure applied to the food by the food-facing surface of the first resin layer of the food package becomes moderate, and the lipid-containing product constituting the surface layer of the food is less likely to adhere to the food-facing surface of the first resin layer, which makes it possible to further prevent deterioration of the appearance of the food package.

[0015] The packaging film preferably has a haze of 40% or less.

[0016] In this case, the transparency of the packaging film is further improved, and the visibility of the food inside the food package is further improved.

[0017] The present invention also relates to a packaging bag used for packaging food having a surface layer made of a lipid-containing product containing 40% or more by mass of lipids, the packaging bag being formed using the above-mentioned packaging film, and the first resin layer of the packaging film being arranged with the food-facing surface facing toward the inside of the packaging bag.

[0018] This packaging bag makes it difficult for lipid-containing products contained in the surface layer of the food to adhere to the food-facing surface of the first resin layer of the packaging film, so that when the food is placed in the packaging bag to form a food package, deterioration of the appearance of the food package can be suppressed.

[0019] Furthermore, the present invention relates to a food package comprising the above-mentioned food packaged inside the packaging bag.

[0020] According to this food package, the lipid-containing product contained in the surface layer of the food is less likely to adhere to the food-facing surface of the first resin layer of the packaging film, thereby preventing deterioration of the appearance of the food package. Effect of the Invention

[0021] According to the present invention, a packaging film, a packaging bag, and a food package are provided that can suppress deterioration in the appearance of a food package when a packaging bag is formed and a food having a surface layer composed of a lipid-containing product containing 40% or more by mass of lipids is placed inside the packaging bag to form a food package. [Brief description of the drawings]

[0022] [Figure 1] 1 is a front view showing one embodiment of a food packaging body of the present invention. [Diagram 2] 2 is a cross-sectional view of a packaging film constituting the packaging bag of the food package of FIG. 1. [Diagram 3] 2 is a cross-sectional view of the food that constitutes the food package of FIG. 1. [Figure 4] FIG. 4 is a front view showing another embodiment of the food packaging body of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment of a food package of the present invention will be described in detail with reference to Figures 1 to 3. Figure 1 is a front view showing one embodiment of a food package of the present invention, Figure 2 is a cross-sectional view of a packaging film constituting a packaging bag of the food package of Figure 1, and Figure 3 is a cross-sectional view of a food that constitutes the food package of Figure 1.

[0024] As shown in Fig. 1, a food package 100 includes a packaging bag 10 and a food 20 contained inside the packaging bag 10. As shown in Fig. 2, the packaging bag 10 includes a sealant layer 12 and a base layer 11 provided on the sealant layer 12, and is formed using a packaging film 110 used for packaging the food 20. The sealant layer 12 is disposed on the food 20 side and includes a first resin layer 12A having a food-facing surface S for facing the food 20, and a second resin layer 12B disposed on the opposite side of the food-facing surface S of the first resin layer 12A. The base layer 11 is disposed on the opposite side of the sealant layer 12 to the food-facing surface S of the first resin layer 12A. The first resin layer 12A contains (A) a polyolefin resin and (B) a silylated polyolefin.

[0025] On the other hand, as shown in FIG. 3, food product 20 includes main body 20A and surface layer 20B provided on the surface of main body 20A, and surface layer 20B is made of a lipid-containing product containing 40% or more by mass of lipids.

[0026] In this food package 100, the first resin layer 12A of the sealant layer 12 contains (A) a polyolefin resin and (B) a silylated polyolefin, which makes it difficult for the lipid-containing product of the food 20 to adhere to the food-facing surface S of the first resin layer 12A. Therefore, the food package 100 can suppress deterioration of its appearance.

[0027] The packaging film 110, the food 20, and the food package 100 will be described in detail below.

[0028] <Packaging film> The packaging film 110 includes the base layer 11 and the sealant layer 12 as described above.

[0029] <Base material layer> By including the base material layer 11 in the packaging film 110, the sealant layer 12 is reinforced by the base material layer 11, and the mechanical strength of the packaging film 110 is improved. In addition, by including the base material layer 11 in the packaging film 110, it is possible for the packaging film 110 to have functions such as barrier properties and light blocking properties. The base material layer 11 is not particularly limited as long as it can reinforce the sealant layer 12, and a specific example of the base material layer 11 is a resin film. Examples of the resin film include films containing at least one of polyester (e.g., polyethylene terephthalate (PET)), polyamide (PA), polyvinyl chloride (PVC), cellulose acetate, and cellophane resin. This film may be a stretched film or a non-stretched film. The base material layer 11 may be a laminate of multiple base materials of different materials as necessary to improve heat resistance, impact resistance, oxygen and water vapor barrier properties, etc.

[0030] The thickness of the base layer 11 is not particularly limited and can be appropriately adjusted depending on the application. The thickness of the base layer 11 is usually 1 to 500 μm, but from the viewpoint of improving the transparency of the packaging film 110, it is preferably 10 to 100 μm.

[0031] <Sealant layer> The sealant layer 12 has a first resin layer 12A having a food-facing surface S, and a second resin layer 12B disposed on the side opposite to the food-facing surface S of the first resin layer 12A.

[0032] (1st resin layer) The first resin layer 12A contains (A) a polyolefin resin and (B) a silylated polyolefin.

[0033] [(A) Polyolefin resin] The polyolefin resin is not particularly limited, and examples of the polyolefin resin include low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-α-olefin copolymer, homopolypropylene, block polypropylene, random polypropylene, propylene-α-olefin copolymer, etc. Examples of the α-olefin component include 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl-1-pentene, etc. The copolymer may be a random copolymer or a block copolymer. In addition to the above, the polyolefin resin may be a cyclic polyolefin such as polynorbornene. In addition, the polyolefin resin is preferably a linear polyolefin from the viewpoint of sealing property and strength properties (tensile strength, impact strength, etc.), and the linear polyolefin may be straight-chain or branched.

[0034] Examples of polypropylene resins include homopolypropylene, block polypropylene, random polypropylene, and the above-mentioned copolymers of α-olefin and propylene (propylene-based copolymers). Among these, the polypropylene resin preferably contains random polypropylene. By containing random polypropylene, it becomes easier to prevent the packaging film 110 from being torn by heat, and it also tends to be easier to heat seal at low temperatures in a short time.

[0035] The polyolefin resin may be a modified polyolefin modified with a specific acid. The modified polyolefin is obtained by graft-modifying a polyolefin with an unsaturated carboxylic acid derivative component derived from, for example, an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, or an ester of an unsaturated carboxylic acid. In addition, modified polyolefins such as hydroxyl-modified polyolefins and acrylic-modified polyolefins can also be used as the polyolefin resin.

[0036] The above-mentioned polyolefin resins may be used alone or in combination of two or more.

[0037] [(B) Silylated polyolefin] The silylated polyolefin contains a first structural unit derived from an olefin and a second structural unit represented by the following formula (1). [ka] (In the above formula (1), R 1 and R 2 each independently represents a hydrogen atom, a halogen atom, a hydrocarbon group, an oxygen-containing group, or a silicon-containing group, and when a plurality of second structural units are present, R 1 and R 2 may be the same or different. Y represents O, S, or NR (R represents a hydrogen atom or a hydrocarbon group).

[0038] The first structural unit is a structural unit derived from an olefin, such as an alkylene, for example, ethylene or propylene.

[0039] The hydrocarbon group in the second structural unit is not particularly limited, but specific examples of the hydrocarbon group include alkyl groups such as a methyl group and an ethyl group, alkenyl groups such as a vinyl group, and aryl groups such as a phenyl group.

[0040] The oxygen-containing group in the second structural unit is not particularly limited, and specific examples of the oxygen-containing group include alkoxy groups such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a hexyloxy group, an octyloxy group, a benzyloxy group, and a 2-phenylethoxy group, and aryloxy groups such as a phenoxy group, a tolyloxy group, a biphenyloxy group, and a naphthyloxy group.

[0041] The silicon-containing group in the second structural unit is not particularly limited, and specific examples of the silicon-containing group include alkylsilyl groups, alkenylsilyl groups, arylsilyl groups, alkylsiloxy groups, alkenylsiloxy groups, arylsiloxy groups, alkoxysilyl groups, aryloxysilyl groups, alkoxysiloxy groups, aryloxysiloxy groups, and polysiloxyl.

[0042] The silylated polyolefin may be a block copolymer or a graft copolymer, but is preferably a block copolymer. In this case, the second structural unit of the block copolymer is more likely to bleed out to the food-facing surface S side of the first resin layer 12A than the graft copolymer, improving the adhesion prevention property of lipid-containing products and further suppressing deterioration of the appearance of the food package 100.

[0043] Examples of silylated polyolefins include PE-Si graft copolymers such as products manufactured by Dow Corning Toray Co., Ltd., PE-Si block copolymers such as Exfora manufactured by Mitsui Fine Chemicals Co., Ltd., and PP-Si graft copolymers such as products manufactured by Dow Corning Toray Co., Ltd.

[0044] As the silylated polyolefin, a block copolymer is more preferable than a graft copolymer in terms of further improving the adhesion prevention property of the first resin layer 12A against lipid-containing products, because the block copolymer tends to be unevenly distributed or bleed out easily on the food-facing surface S of the first resin layer 12A.

[0045] The above-mentioned silylated polyolefins can be used alone or in combination of two or more.

[0046] The content of the (B) silylated polyolefin in the first resin layer 12A is preferably 0.1 to 50 mass%, more preferably 1 to 40 mass%, and even more preferably 2 to 30 mass%, based on the total amount of the (A) polyolefin resin and the (B) silylated polyolefin. If the content of the (B) silylated polyolefin is equal to or greater than the lower limit, the lipid-containing product tends to adhere less easily to the first resin layer 12A. On the other hand, if the content of the (B) silylated polyolefin is equal to or less than the upper limit, the content of the (A) polyolefin resin increases relatively, and therefore good heat sealability tends to be obtained.

[0047] The first resin layer 12A may contain other additives as necessary to the extent that they do not impair the appearance of the food package 100. Examples of other additives include flame retardants, slip agents, antiblocking agents, antioxidants, light stabilizers, and tackifiers.

[0048] The thickness of the first resin layer 12A is preferably 0.1 to 100 μm, more preferably 1 to 70 μm, even more preferably 3 to 50 μm, and particularly preferably 5 to 30 μm. When the thickness of the first resin layer 12A is equal to or greater than the lower limit, good adhesion to the lipid-containing product and good heat sealability tend to be easily obtained. On the other hand, when the thickness is equal to or less than the upper limit, the thickness of the entire packaging film 110 can be made thin.

[0049] (2nd resin layer) The second resin layer 12B may be made of a material having heat sealability. When the sealant layer 12 has the second resin layer 12B, the lipid-containing product of the food 20 tends to be less likely to adhere to the food-facing surface S of the first resin layer 12A. Furthermore, when the sealant layer 12 further has the second resin layer 12B, the packaging film 110 can have further functionality (heat resistance, impact resistance, etc.). Furthermore, the first resin layer 12A can be made thinner, and the cost of the packaging film 110 can be reduced.

[0050] Such a material having heat sealability is usually a thermoplastic resin. The thermoplastic resin used in the second resin layer 12B is not particularly limited, but examples of the thermoplastic resin include polyolefin resin, ethylene-α,β-unsaturated carboxylic acid copolymer or its ester or ion crosslinked product, ethylene-vinyl acetate copolymer or its saponification product, polyvinyl acetate or its saponification product, polycarbonate resin, thermoplastic polyester resin, ABS resin, polyacetal resin, polyamide resin, polyphenylene oxide resin, polyimide resin, polyurethane resin, polylactic acid resin, furan resin, and silicone resin. These thermoplastic resins can be used alone or in combination of two or more.

[0051] Since the thermoplastic resin used for the second resin layer 12B is likely to have improved heat sealability, heat resistance, and impact resistance, it preferably contains a polyolefin resin. As the polyolefin resin, the same resin as the (A) polyolefin resin used for the first resin layer 12A can be used.

[0052] When the second resin layer 12B is in contact with the first resin layer 12A, the melting point T1 (°C) of the (A) polyolefin resin in the first resin layer 12A and the melting point T2 (°C) of the thermoplastic resin in the second resin layer 12B preferably satisfy the relationship T1 < T2. By satisfying the above relationship, from the viewpoint of crystallinity, migration of the (B) silylated polyolefin in the first resin layer 12A to the second resin layer 12B can be suppressed, and the efficiency of uneven distribution or bleed-out of the (B) silylated polyolefin on the food-facing surface S of the first resin layer 12A can be improved. Therefore, adhesion of lipid-containing products to the first resin layer 12A can be more effectively suppressed. From the same viewpoint, the melting point T2 is preferably 1°C or more higher than the melting point T1, and more preferably 3°C or more higher.

[0053] The thickness of the second resin layer 12B can be appropriately set according to the food 20. The thickness of the second resin layer 12B is preferably, for example, 0.1 to 300 μm, more preferably 1 to 200 μm, still more preferably 5 to 150 μm, and particularly preferably 10 to 100 μm.

[0054] The sealant layer 12 is usually provided so as to cover the entire surface of the base material layer 11, but it may be provided so as to cover only a part of the surface of the base material layer 11. Further, the sealant layer 12 may further include one or more other resin layers in addition to the first resin layer 12A and the second resin layer 12B. The composition of the other resin layer may be the same as or different from the composition of the second resin layer 12B.

[0055] The thickness of the sealant layer 12 is not particularly limited, but from the viewpoint of preventing deterioration in the appearance of the food package 100, it is preferably 40 to 80 μm, and more preferably 50 to 70 μm.

[0056] (rigidity value) In the packaging film 110, the stiffness value in a loop stiffness measurement with a loop length of 85 mm is not particularly limited, but is preferably 5 to 55 mN.

[0057] In this case, the pressure applied to the food 20 by the inner surface of the food package 100 becomes moderate, and the lipid-containing product constituting the surface layer portion 20B of the food 20 is less likely to adhere to the food-facing surface S of the first resin layer 12A. This further suppresses deterioration of the appearance of the food package 100. Specifically, the stiffness of the packaging film 110 becomes stronger compared to when the stiffness value is less than 5 mN. As a result, the packaging film 110 is prevented from adhering to the food 20 due to film twisting, and the food 20 is less likely to adhere to the food-facing surface S of the packaging film 110, so deterioration of the appearance of the food package 100 is suppressed. In addition, compared to when the stiffness value exceeds 55 mN, the packaging film 110 is more likely to follow the shape of the food 20. This makes it difficult for the packaging film 110 to be pressed against the food 20, and the food 20 is less likely to adhere to the packaging film 110, so deterioration of the appearance of the food package 100 is suppressed. The stiffness value of the packaging film 110 is more preferably 8 to 40 mN, and particularly preferably 10 to 20 mN.

[0058] (Hayes) The haze of the packaging film 110 is not particularly limited, but is preferably 40% or less. In this case, the visibility of the food 20 from the outside of the food package 100 is further improved. From the viewpoint of the visibility of the food 20, the haze of the packaging film 110 is more preferably 30% or less, and particularly preferably 20% or less. Haze is divided into external haze caused by the surface unevenness of the sealant layer 12 or the base layer 11, and internal haze depending on the crystallinity, crystal size, etc., but the haze in the present invention includes external haze and internal haze. In addition, the haze is not the haze of the sealant layer 12 or the base layer 11, but the haze of the entire packaging film 110.

[0059] The thickness of the packaging film 110 is not particularly limited, but from the viewpoint of preventing deterioration in the appearance of the food package 100, it is preferably 40 to 120 μm, and more preferably 50 to 80 μm.

[0060] The packaging film 110 can be produced, for example, by a lamination method using an adhesive and a lamination method using heat treatment, as described below.

[0061] (Lamination method using adhesive) As a lamination method using an adhesive, various known lamination methods can be used, such as dry lamination, wet lamination, non-solvent lamination, etc. Examples of adhesives used in these lamination methods include the following.

[0062] The adhesive bonds the sealant layer 12 and the base layer 11. Examples of the adhesive include polyurethane resins in which a difunctional or higher isocyanate compound is allowed to react with a base material such as polyester polyol, polyether polyol, acrylic polyol, or carbonate polyol. The above-mentioned various polyols may be used alone or in combination of two or more.

[0063] For the purpose of promoting adhesion, the adhesive may further contain a carbodiimide compound, an oxazoline compound, an epoxy compound, a phosphorus compound, a silane coupling agent, or the like, in addition to the polyurethane resin described above.

[0064] Depending on the performance required for the adhesive, various other additives and stabilizers may be blended with the polyurethane resin described above.

[0065] The thickness of the adhesive is not particularly limited, but from the viewpoint of obtaining the desired adhesive strength, followability, processability, and the like, the thickness is, for example, preferably 1 to 10 μm, and more preferably 3 to 7 μm.

[0066] (Lamination method using heat treatment) The lamination method by heat treatment can be broadly classified into the following methods. (1) A method in which a sealant layer 12 that has been previously formed is extrusion laminated onto a substrate layer 11 together with an adhesive resin. (2) A method in which the resin layer constituting the sealant layer 12 and an adhesive resin are extrusion laminated onto the base material layer 11. (3) A method in which the laminate substrate obtained by the above method (1) or (2) is further heated and pressed with a heated roll to bond the laminate substrate. (4) The laminate substrate obtained by the above method (1) or (2) is further stored in a high-temperature atmosphere, or passed through a drying / baking furnace in a high-temperature atmosphere.

[0067] Examples of adhesive resins used in the lamination method by heat treatment include acid-modified polyolefins, etc. In the above method, the base layer 11 and the sealant layer 12 are laminated by extrusion lamination, but it is also possible to coat and form an acid-modified polyolefin-based coating agent (dissolution type, dispersion type) on the base layer 11 in advance without extrusion lamination, and then laminate the sealant layer 12 by heat treatment.

[0068] In addition, an adhesive primer (anchor coat) can be applied to the base layer 11, and materials that can be used for this include polyester, polyurethane, polyallylamine, polyethyleneimine, polybutadiene, ethylene-vinyl acetate copolymer, and chlorine-vinyl acetate. If necessary, the various curing agents and additives described above that can be used as adhesives may be blended into the base layer 11.

[0069] ≪Food≫ The food product 20 includes a main body 20A and a surface layer 20B provided on the surface of the main body 20A, and the surface layer 20B is made of a lipid-containing product containing 40% or more by mass of lipids. In the food product 20, only the surface layer 20B may be made of a lipid-containing product, or the entire food product 20 including the surface layer 20B may be made of a lipid-containing product. Note that the surface layer 20B does not necessarily have to be provided on the entire surface of the main body 20A as shown in FIG. 3, and may be provided only on a part of the surface.

[0070] Lipids are a general term for organic compounds in food that dissolve in organic solvents. In addition to neutral fats, It also contains phospholipids, steroids, waxes, fat-soluble vitamins, etc. The acid decomposition method is used to analyze the amount of lipids in foods.

[0071] The lipid-containing product may be any product containing lipids at 40% by mass or more, and specific examples of such lipid-containing products include glace and chocolate. The melting point of the lipid-containing product is usually 25 to 60° C. The lipid-containing product may contain lipid-containing materials such as butter, margarine, fresh cream, cream cheese, lard, and beef tallow, and lipids may be contained in such lipid-containing materials.

[0072] The main body 20A is not particularly limited as long as it is a food product, and specific examples of the main body 20A include lipid-containing products, cookies, donuts, waffles, bread, cream puffs, marshmallows, etc. The lipid-containing products may be the same as or different from the lipid-containing products described above.

[0073] Although FIG. 1 shows food packaging 100 containing a plurality of food items 20, food packaging 200 shown in FIG. 4 may contain only one food item 20.

[0074] ≪Food packaging≫ The food package 100 can be formed using the above-mentioned packaging film 110 by the following method. (1) A method in which one packaging film 110 is folded with the first resin layer 12A on the inside, and a portion of the film is left uncovered and heat-sealed to obtain a pouch, and then food 20 is placed through an opening in the portion of the pouch that has not been heat-sealed, and finally the opening is heat-sealed to hermetically seal the food 20. (2) A method in which two packaging films 110 are overlapped with the first resin layers 12A facing each other, and a pouch is obtained by heat-sealing all but a portion of the pouch, placing food 20 through an opening in the portion of the pouch that has not been heat-sealed, and finally heat-sealing the opening to hermetically seal the food 20. (3) A method in which three packaging films 110, two of which are used as side portions and one as the bottom portion, are arranged with the first resin layer 12A facing inward, and the remaining portions are heat-sealed to obtain a self-supporting pouch, and then food 20 is placed through an opening in the portion of the pouch that has not been heat-sealed, and finally the opening is heat-sealed to hermetically seal the food 20.

[0075] The present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the packaging film 110 has the sealant layer 12 and the base material layer 11, but does not necessarily have to have the base material layer 11.

[0076] In the above embodiment, the sealant layer 12 has the first resin layer 12A and the second resin layer 12B, but it does not necessarily have to have the second resin layer 12B. EXAMPLES

[0077] The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples.

[0078] <Preparation of resin composition for forming first resin layer> A resin composition for forming a first resin layer was prepared by mixing the polyolefin resin (A) of the type shown in Tables 1 and 2 with the silylated polyolefin (B) shown in Tables 1 and 2. The contents of the polyolefin resin (A) and the silylated polyolefin (B) were adjusted so that the silylated polyolefin (B) was 5 mass% and the polyolefin resin (A) was 95 mass%, based on the total amount of the polyolefin resin (A) and the silylated polyolefin (B).

[0079] (Examples 1 to 3) The resin composition for forming the first resin layer obtained as described above was extruded using an extruder to form a film having the thickness shown in Tables 1 and 2 to obtain a resin film for forming the first resin layer. Then, this resin film for forming the first resin layer and a film for forming a base material layer made of the type shown in Tables 1 and 2 and having the thickness shown in Tables 1 and 2 were dry laminated using a polyurethane adhesive (manufactured by Mitsui Chemicals, Inc.), and aged at 50°C for 4 days to obtain a laminate for a packaging film with a haze value shown in Tables 1 and 2. Then, a packaging film having a dimension of 160 mm x 120 mm was cut out from this laminate for a packaging film. Next, this packaging film was folded in two so that the first resin layer was on the inside, and one side of the vertical end and one side of the horizontal end (the side opposite to the folded side) were heat sealed with a heat sealer at 190°C, 0.03 MPa, and 2 sec over a width of 10 mm to form a sealed portion, and a pouch was produced as a packaging bag with one side of the vertical end open. Next, one food product made of a square cookie (80 mm x 55 mm, maximum thickness 8 mm) coated with glace (containing 56% by mass of lipids) was filled from the opening of the pouch. Then, the opening was heat sealed with a heat sealer at 190°C, 0.03 MPa, and 2 sec over a width of 10 mm to form a sealed portion, and the pouch was sealed. In this way, a food package was obtained.

[0080] (Examples 4 to 14) The resin composition for forming the first resin layer obtained as described above was extruded using an extruder to form a film having the thickness shown in Tables 1 and 2 to obtain a resin film for forming the first resin layer. Then, this resin film for forming the first resin layer, a resin film for forming the second resin layer consisting of the type shown in Tables 1 and 2 and having the thickness shown in Tables 1 and 2, and a film for forming the base material layer consisting of the type shown in Tables 1 and 2 and having the thickness shown in Tables 1 and 2 were dry laminated using a polyurethane adhesive (manufactured by Mitsui Chemicals, Inc.), and aged at 50°C for 4 days to obtain a laminate for a packaging film such that the haze was the value shown in Tables 1 and 2. Then, a packaging film having a dimension of 160 mm x 120 mm was cut out from this laminate for a packaging film. Next, this packaging film was folded in two so that the first resin layer was on the inside, and one side of the vertical end and one side of the horizontal end (the side opposite to the folded side) were heat sealed with a heat sealer at 190°C, 0.03 MPa, and 2 sec over a width of 10 mm to form a sealed portion, and a pouch was produced as a packaging bag with one side of the vertical end open. Next, one food product made of a square cookie (80 mm x 55 mm, maximum thickness 8 mm) coated with glace (containing 56% by mass of lipids) was filled from the opening of the pouch. Then, the opening was heat sealed with a heat sealer at 190°C, 0.03 MPa, and 2 sec over a width of 10 mm to form a sealed portion, and the pouch was sealed. In this way, a food package was obtained.

[0081] Comparative Example 1 A food packaging body was produced in the same manner as in Example 2, except that the silylated polyolefin (B) was not added to the polyolefin resin (A) when the resin composition for forming the first resin layer was prepared.

[0082] Example 15 A food packaging body was prepared in the same manner as in Example 7, except that in the first resin layer, the content of silylated polyolefin (B) based on the total amount of polyolefin resin (A) and silylated polyolefin (B) was 2 mass%.

[0083] (Example 16) A food packaging body was prepared in the same manner as in Example 7, except that in the first resin layer, the content of silylated polyolefin (B) based on the total amount of polyolefin resin (A) and silylated polyolefin (B) was 10 mass%.

[0084] (Example 17) A food packaging body was prepared in the same manner as in Example 7, except that in the first resin layer, the content of silylated polyolefin (B) based on the total amount of polyolefin resin (A) and silylated polyolefin (B) was 15 mass%.

[0085] (Example 18) A packaging film having dimensions of 90 mm x 60 mm was cut out from the packaging film laminate to create a pouch, and a food package was produced in the same manner as in Example 7, except that raw chocolate (20 mm x 20 mm, maximum thickness 10 mm) consisting of a lipid-containing product (lipid: 42% by mass) was used as the food.

[0086] Comparative Example 2 A packaging film having dimensions of 90 mm x 60 mm was cut out from the packaging film laminate to create a pouch, and a food package was produced in the same manner as in Comparative Example 1, except that raw chocolate (20 mm x 20 mm, maximum thickness 10 mm) made of a lipid-containing product (lipid content: 42% by mass) was used as the food.

[0087] (Example 19) A packaging film having dimensions of 220 mm x 130 mm was cut out from the packaging film laminate to create a pouch, and a food package was produced in the same manner as in Example 7, except that a ring-shaped donut (outer diameter: 70 cm, inner diameter: 25 cm, maximum thickness: 25 cm) coated with a lipid-containing product (lipid content: 51% by mass) was used as the food.

[0088] Comparative Example 3 A food package was prepared in the same manner as in Comparative Example 1, except that a ring-shaped donut (outer diameter: 70 cm, inner diameter: 25 cm, maximum thickness: 25 cm) coated with a lipid-containing product (lipid content: 51% by mass) was used as the food.

[0089] (Example 20) A packaging film having dimensions of 120 mm x 80 mm was cut out from the packaging film laminate to create a pouch, and a food package was produced in the same manner as in Example 7, except that a disk-shaped raisin butter (diameter: 40 mm, maximum thickness: 6 mm) made of a lipid-containing product (lipid: 65% by mass) was used as the food.

[0090] Comparative Example 4 A packaging film having dimensions of 120 mm x 80 mm was cut out from the packaging film laminate to create a pouch, and a food package was produced in the same manner as in Comparative Example 1, except that a disk-shaped raisin butter (diameter: 40 mm, maximum thickness: 6 mm) made of a lipid-containing product (lipid: 65% by mass) was used as the food.

[0091] Details of each component in Tables 1 and 2 are as follows: "-" in Tables 1 and 2 means that the corresponding component was not used.

[0092] [(A) Polyolefin resin] PE1: Linear low-density polyethylene (LLDPE), product name "Evolue SP2020", manufactured by Prime Polymer Co., Ltd., melting point: 116°C PE2: Linear low-density polyethylene (LLDPE), product name "Novatec LL UF442", manufactured by Japan Polypropylene Corporation, melting point: 123°C PP1: A mixture of propylene-ethylene random copolymer (product name "F744NP", manufactured by Prime Polymer Co., Ltd.) and propylene-ethylene block copolymer (product name "Novatec BC5FA", manufactured by Japan Polypropylene Corporation) in a 1:1 (mass ratio) mixture. PP2: Propylene-ethylene block copolymer (product name "Novatec BC3HF", manufactured by Japan Polypropylene Corporation)

[0093] [(B) Silylated polyolefin] PE-Si graft copolymer: Product name "BY27-213", manufactured by Dow Corning Toray Co., Ltd. PE-Si-PE triblock copolymer: Trade name "EXFOLA", manufactured by Mitsui Fine Chemicals, Inc. PP-Si graft copolymer: Product name "BY27-201", manufactured by Dow Corning Toray Co., Ltd.

[0094] PET: Polyethylene terephthalate film (product name "GL BARRIER", manufactured by Toppan Printing Co., Ltd.) PET / Ny: A laminate made by bonding a polyethylene terephthalate (PET) film (product name "Embret", manufactured by Unitika Ltd.) and a nylon (Ny) film (product name "Bonyl QC", manufactured by Kohjin Film & Chemicals Co., Ltd.) with an adhesive.

[0095] [Characteristics of packaging film] (Measurement of stiffness value) Samples having dimensions of 200 mm x 15 mm (width) were cut out from the laminates for packaging films obtained in the process of producing the food packages of Examples 1 to 20 and Comparative Examples 1 to 4. Then, the stiffness values ​​of these samples were measured using a loop stiffness tester (product name: Loop Stiffness Tester DA-S, manufactured by Toyo Seiki Seisakusho Co., Ltd.) in a state where the samples were deformed to a loop length of 85 mm. The results are shown in Tables 1 and 2.

[0096] (Haze value measurement) Samples having dimensions of 50 mm x 50 mm were cut out from the laminates for packaging films obtained in the process of producing the food packages of Examples 1 to 20 and Comparative Examples 1 to 4. The haze values ​​of these samples were measured using a haze meter (product name "Haze Meter NDH-2000", manufactured by Nippon Denshoku Industries Co., Ltd.). The results are shown in Tables 1 and 2. The haze was measured by irradiating light from the base layer side.

[0097] [Evaluation of food packaging] (1) Appearance evaluation The food packages of Examples 1 to 20 and Comparative Examples 1 to 4 were left to stand at room temperature (25°C) for 3 days, and the appearance of the food packages was visually observed. The appearance was then evaluated according to the following criteria. The results are shown in Tables 1 and 2. The level of appearance of the food packages was judged based on the state of adhesion of the glaze inside the food packages. (standard) ◎: Appearance is very good ○: Appearance is good △: Appearance is somewhat good ×: Appearance is not good

[0098] (2) Amount of lipid-containing product attached After observing the appearance of the food packages of Examples 1 to 20 and Comparative Examples 1 to 4, a portion of the food package was cut out to remove the food inside, and the amount of glaze adhering to the inner surface of the pouch was measured. The results are shown in Tables 1 and 2. The amount of glaze adhering is the difference between the mass of the pouch before the food was placed in and the mass of the food package (including the cut-out portion) after the food was removed.

[0099] (3) Evaluation of food visibility The food packages of Examples 1 to 20 and Comparative Examples 1 to 4 were observed to examine the visibility of the foods. The visibility of the foods was then evaluated based on the following criteria. The results are shown in Tables 1 and 2. (standard) ◎: Visibility is extremely good 〇: Good visibility △: Visibility is somewhat good

[0100] [Table 1]

[0101] [Table 2]

[0102] The results shown in Tables 1 and 2 reveal that the food packages of Examples 1-20 had better appearances than the food packages of Comparative Examples 1-4.

[0103] Therefore, it has been confirmed that the packaging film of the present invention can suppress deterioration in the appearance of a food package when a packaging bag is formed and a food having a surface layer composed of a lipid-containing product containing 40% or more by mass of lipids is placed inside the packaging bag to form a food package. [Explanation of symbols]

[0104] 10...Packaging bag, 11...Base material layer, 12...Sealant layer, 12A...First resin layer, 12B...Second resin layer, 20...Food, 20A...Main part, 20B...Surface layer part, 100...Food package, S...Food facing surface.

Claims

1. For packaging food products with a surface layer made of lipid-containing products that contain 40% or more lipid by mass. The packaging film used is A sealant layer having a first resin layer is provided, The first resin layer has a food facing surface for facing the food, the first resin layer contains (A) a polyolefin resin and (B) a silylated polyolefin, A packaging film having a stiffness value of 5 to 46 mN in a loop stiffness measurement with a loop length of 85 mm.

2. The packaging film of claim 1 , wherein the sealant layer further comprises a second resin layer on a side opposite the food-facing surface of the first resin layer.

3. 3. The packaging film according to claim 1, further comprising a base layer provided on the sealant layer, the base layer being positioned on the opposite side of the sealant layer from the food-facing surface of the first resin layer.

4. The packaging film according to any one of claims 1 to 3, having a haze of 40% or less.

5. For packaging food products with a surface layer made of lipid-containing products that contain 40% or more lipid by mass. A packaging bag used in the present invention comprises: A packaging film according to any one of claims 1 to 4, A packaging bag, wherein the first resin layer of the packaging film is arranged with the food-facing surface facing the inside of the packaging bag.

6. A food package comprising the packaging bag according to claim 5 and a food product contained therein.

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