Vinylidene chloride-based resin film and filled package using the same

Abstract

The present invention provides a vinylidene chloride resin film and a filling package using the same, wherein the vinylidene chloride resin film eliminates the problem of insufficient color retention time of the contents before and after a retort treatment when the contents are filled and packaged. The vinylidene chloride resin film of the present invention contains a vinylidene chloride resin, wherein a content containing 20% by mass of lipids is filled and sealed in the tubular vinylidene chloride resin film with both ends in the longitudinal direction being gathered to form a filling package, and the filling package is subjected to pressure heat sterilization in hot water at 120°C under 0.2 MPa for 10 minutes, and the oxygen permeability of the vinylidene chloride resin film before the pressure heat sterilization is set to A (cm 3 / m 2 ·day·atm), the oxygen permeability of the vinylidene chloride resin film after the pressure heat sterilization is converted to 40 μm thickness as B (cm 3 / m 2 ·day·atm), the rate of change in oxygen permeability determined by (B‑A) / A×100 was 35.0% or less.

Description

Technical Field

[0001] The present invention relates to a vinylidene chloride resin film and a filled packaging body using the same. Background Art

[0002] It is known that packaging bodies made by filling a tubular film with contents such as meat or fish and tying both ends can be manufactured using a packaging body manufacturing apparatus. After manufacturing the package, a retort treatment is performed for the purpose of sterilizing or cooking the contents. The packaging body manufacturing apparatus comprises a mechanism for rolling a strip of film into a cylindrical shape, overlapping the side edges, and longitudinally sealing the cylindrical film; a mechanism for filling the tubular film with the contents; and a mechanism for tying both ends of the tubular film filled with the contents. To maintain the flavor and color of the contents after the retort treatment, materials with excellent oxygen barrier properties, such as vinylidene chloride resins, are used in the film used for these packaging bodies (e.g., see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2005-231639 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] It has been conventionally believed that the lower the oxygen permeability of a vinylidene chloride resin film before retorting used in such packaging, the longer the flavor and color of the contents will be retained. However, the oxygen permeability of a vinylidene chloride resin film after retorting is sometimes higher than that before retorting, and even if the oxygen permeability before retorting is low, the flavor and color of the contents may not be retained sufficiently long.

[0008] The present invention has been completed in view of the above-mentioned technical problems, and its purpose is to provide a vinylidene chloride resin film and a filling packaging body using the same, wherein the vinylidene chloride resin film eliminates the insufficient color retention time of the contents before and after the boiling treatment when the contents are filled and packaged.

[0009] Technical Solution

[0010] The present inventors have found that the above-mentioned problems can be solved by controlling the rate of change in oxygen permeability of a vinylidene chloride resin film within a specific range before and after a specific retort treatment, thereby completing the present invention.

[0011] The vinylidene chloride resin film of the present invention comprises a vinylidene chloride resin, wherein a content containing 20% by mass of lipids is filled and sealed in a cylindrical vinylidene chloride resin film having both ends in the longitudinal direction thereof gathered to form a filled package, and the filled package is subjected to pressure heat sterilization in hot water at 120°C under 0.2 MPa for 10 minutes, and the oxygen permeability converted to a thickness of 40 μm of the vinylidene chloride resin film before the pressure heat sterilization is set as A (cm 3 / m 2 ·day·atm), the oxygen permeability of the vinylidene chloride resin film after the pressure heat sterilization is converted to 40 μm thickness as B (cm 3 / m 2 ·day·atm), the rate of change in oxygen permeability determined by (BA) / A×100 is 35.0% or less.

[0012] In the vinylidene chloride resin film, it is preferred that the rate of change in the oxygen permeability be 1.5% or less.

[0013] In the vinylidene chloride resin film, it is preferred that the rate of change in the oxygen permeability is -10.0% or more.

[0014] In the vinylidene chloride resin film, it is preferred that the rate of change in the oxygen permeability is -8.0% or more.

[0015] The vinylidene chloride-based resin film preferably further contains a resin other than the vinylidene chloride-based resin.

[0016] In the vinylidene chloride resin film, it is preferred that the resin other than the vinylidene chloride resin contains at least one resin selected from the group consisting of ultra-low density polyethylene and ionomer resin.

[0017] In the vinylidene chloride resin film, it is preferred that the content of the resin other than the vinylidene chloride resin is 0.5% by mass or more and less than 3% by mass.

[0018] In the vinylidene chloride resin film, it is preferred that the vinylidene chloride resin is a copolymer of 60% by mass to 95% by mass and 5% by mass to 40% by mass of vinyl chloride.

[0019] The filled package of the present invention comprises the above-mentioned vinylidene chloride-based resin film and contents.

[0020] Beneficial effects

[0021] According to the present invention, there can be provided a vinylidene chloride resin film that eliminates the problem of insufficient color retention time of contents before and after retort treatment when filling and packaging the contents, and a filled package using the same. DETAILED DESCRIPTION

[0022] <Vinylidene chloride resin film>

[0023] The vinylidene chloride resin film of the present invention is a vinylidene chloride resin film containing a vinylidene chloride resin, wherein a content containing 20% by mass of lipids is filled and sealed in a cylindrical vinylidene chloride resin film having both ends in the longitudinal direction thereof gathered to form a filled package, and the filled package is subjected to pressure heat sterilization in hot water at 120°C under 0.2 MPa for 10 minutes, and the oxygen permeability converted to a thickness of 40 μm of the vinylidene chloride resin film before the pressure heat sterilization is set as A (cm 3 / m 2 ·day·atm), the oxygen permeability of the vinylidene chloride resin film after the pressure heat sterilization is converted to 40 μm thickness as B (cm 3 / m 2 When the oxygen permeability is measured as (BA) / A×100 (day·atm), the rate of change in oxygen permeability, as determined by (BA) / A×100, is 35.0% or less, preferably 30.0% or less, more preferably 20.0% or less, even more preferably 2.0% or less, and particularly preferably 1.5% or less. When the rate of change in oxygen permeability is 35.0% or less, insufficient color retention time of the contents can be easily eliminated. The lower limit of the rate of change in oxygen permeability is not particularly limited and may be -10.0% or greater, or -8.0% or greater. The lipid used to measure the rate of change in oxygen permeability is not particularly limited; for example, pig fat may be used.

[0024] The vinylidene chloride resin film may further contain a resin other than the vinylidene chloride resin. The resin other than the vinylidene chloride resin may contain at least one resin selected from the group consisting of ultra-low density polyethylene and ionomer resin.

[0025] 〔Polyvinylidene chloride resin〕

[0026] Polyvinylidene chloride resin (hereinafter sometimes referred to as "PVDC") may be a homopolymer of vinylidene chloride or a copolymer of 60 to 98% by mass of vinylidene chloride and 2 to 40% by mass of another monomer copolymerizable with vinylidene chloride. Examples of the other monomer copolymerizable with vinylidene chloride include: vinyl chloride; alkyl acrylates (alkyl groups having 1 to 18 carbon atoms) such as methyl acrylate, ethyl acrylate, butyl acrylate, and lauryl acrylate; alkyl methacrylates (alkyl groups having 1 to 18 carbon atoms) such as methyl methacrylate, butyl methacrylate, and lauryl methacrylate; vinyl cyanides such as acrylonitrile; aromatic vinyls such as styrene; vinyl esters of aliphatic carboxylic acids having 1 to 18 carbon atoms such as vinyl acetate; alkyl vinyl ethers having 1 to 18 carbon atoms; vinyl-polymerizable unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid; and alkyl esters (including partial esters, alkyl groups having 1 to 18 carbon atoms) of vinyl-polymerizable unsaturated carboxylic acids such as maleic acid, fumaric acid, and itaconic acid. More preferably, it is at least one selected from vinyl chloride, methyl acrylate and lauryl acrylate. Other monomers copolymerizable with vinylidene chloride may be used alone or in combination of two or more. The copolymerization ratio of other monomers is more preferably in the range of 3 to 35% by mass, further preferably 3 to 29% by mass, and particularly preferably in the range of 4 to 22% by mass. When the copolymerization ratio of other monomers is 3% by mass or more, the melt processability is not easily reduced. On the other hand, when the copolymerization ratio of other monomers is 35% by mass or less, the gas barrier properties are not easily reduced. In addition, in order to improve the melt processability, two or more PVDCs may be mixed. PVDC can be synthesized by any polymerization method such as suspension polymerization, emulsion polymerization, solution polymerization, etc. PVDC may be used alone or in combination of two or more.

[0027] In particular, when the other monomer copolymerizable with vinylidene chloride is vinyl chloride, from the viewpoints of melt processability, gas barrier properties, etc., PVDC is preferably a copolymer of 60% by mass to 95% by mass of vinylidene chloride and 5% by mass to 40% by mass of vinyl chloride, more preferably a copolymer of 63% by mass to 90% by mass of vinylidene chloride and 10% by mass to 37% by mass of vinyl chloride, further preferably a copolymer of 66% by mass to 85% by mass of vinylidene chloride and 15% by mass to 34% by mass of vinyl chloride, and particularly preferably a copolymer of 69% by mass to 83% by mass of vinylidene chloride and 17% by mass to 31% by mass of vinyl chloride.

[0028] Ultra-low-density polyethylene

[0029] Ultra-low density polyethylene refers to polyethylene with a density of 0.915 g / cm 3The polyethylene mentioned below refers to an ethylene-α-olefin copolymer having a C4 to C8 α-olefin comonomer such as butene, hexene, or octene. Ultra-low density polyethylene may be used alone or in combination of two or more.

[0030] 〔Ionomer resin〕

[0031] The ionomer resin is a compound in which at least a portion of the acidic groups of an ethylene-unsaturated carboxylic acid copolymer (base polymer) is neutralized with metal ions. The ionomer resin may be used alone or in combination of two or more.

[0032] Examples of the structural unit derived from an unsaturated carboxylic acid include structural units derived from acrylic acid, methacrylic acid, fumaric acid, maleic acid, and the like.

[0033] The ethylene-unsaturated carboxylic acid-based copolymer (base polymer) forming the ionomer resin is a copolymer of at least ethylene and an unsaturated carboxylic acid, and has a structural unit derived from ethylene and a structural unit derived from the unsaturated carboxylic acid.

[0034] Among them, (meth)acrylic acid is preferred as the structural unit derived from an unsaturated carboxylic acid.

[0035] The ethylene-unsaturated carboxylic acid-based copolymer may contain, in addition to the structural units derived from ethylene and the structural units derived from the unsaturated carboxylic acid, structural units derived from monomers other than ethylene and the unsaturated carboxylic acid.

[0036] The metal ion used for neutralizing the acidic groups of the ethylene-unsaturated carboxylic acid copolymer (base polymer) is not particularly limited, but alkali metal ions such as lithium, sodium, potassium, rubidium, and cesium are preferred, with sodium being particularly preferred.

[0037] In addition, in this specification, "(meth)acrylic acid" means at least one of "acrylic acid" and "methacrylic acid".

[0038] 〔Other resins〕

[0039] The vinylidene chloride resin film of the present invention may contain other resins except polyvinylidene chloride resin, ultra-low density polyethylene and ionomer resin as required for the purpose of improving various characteristics and / or molding processability. As other resins, there is no particular limitation, and for example, polyethylene wax, oxidized polyethylene wax, low density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-butyl acrylate copolymer (EBA) etc. may be listed. Other resins may be used alone or in combination of two or more.

[0040] 〔Resin content〕

[0041] In the vinylidene chloride resin film of the present invention, the content of the resin other than the vinylidene chloride resin is preferably 0.5 mass % or more and less than 3.0 mass %, more preferably 1.0 mass % or more and less than 3.0 mass %, particularly preferably 1.0 mass % or more and 2.5 mass % or less. When the above-mentioned content is 0.5 mass % or more, the inhibitory effect of the fading of the content after the pressure heat sterilization (retorting) easily becomes sufficient. When the above-mentioned content is less than 3.0 mass %, the film is not easy for white turbidity. In addition, by changing the above-mentioned content, the rate of change of oxygen permeability can be adjusted. On the other hand, in the vinylidene chloride resin film of the present invention, the content of the vinylidene chloride resin is preferably more than 97.0 mass % and less than 99.5 mass %, more preferably more than 97.0 mass % and less than 99.0 mass %, particularly preferably more than 97.5 mass % and less than 99.0 mass %.

[0042] 〔additive〕

[0043] The vinylidene chloride resin film of the present invention may, as needed, contain various additives such as heat stabilizers, plasticizers, processing aids, colorants, UV absorbers, pH adjusters, and dispersing aids, added to improve various properties and moldability of conventional tubular packaging films used in filling packaging. For example, heat stabilizers include epoxy compounds such as epoxidized vegetable oils, epoxidized animal oils, epoxidized fatty acid esters, and epoxy resin prepolymers; and epoxy-group-containing resins, preferably epoxidized vegetable oils. The type and amount of additives can be selected similarly to those used in conventional tubular packaging films used in filling packaging. The additives may be used singly or in combination of two or more. Furthermore, a portion or all of the additives used may be incorporated into the monomer composition during the PVDC polymerization step, or they may be blended with the PVDC after polymerization.

[0044] <Filled package and its manufacturing method>

[0045] The filled package of the present invention comprises the vinylidene chloride resin film of the present invention and content. According to the filled package, insufficient color retention time of the content before and after retorting can be eliminated.

[0046] The contents are not particularly limited and may include lipids. For example, solid or pasty processed foods such as sausages, cheese, butter, and hamburgers, which are conventionally filled into packaging bodies, may be used. The composition and shape of the contents may be appropriately selected. Particularly preferred contents include animal meat sausages and fish meat sausages.

[0047] The method for producing the filled package body of the present invention is not particularly limited as long as the filled package body of the present invention can be obtained by filling and packaging the contents using the vinylidene chloride resin film of the present invention.

[0048] Hereinafter, a filled package and a method for producing the same according to one embodiment of the present invention will be described in detail.

[0049] 1.Tubular packaging film

[0050] A filling package according to one embodiment of the present invention comprises a tubular packaging film and contents. The tubular packaging film has a longitudinally extending seal portion and is converged at both ends in the longitudinal direction. The packaging film comprises the vinylidene chloride resin film of the present invention. Alternatively, the packaging film can be composed of the vinylidene chloride resin film of the present invention.

[0051] [Size and thickness of tubular packaging film]

[0052] The size and thickness of the tubular packaging film are not particularly limited and can be determined based on the size of the contents to be filled. The circumference of the tubular packaging film is, for example, 15 to 400 mm, often 30 to 300 mm, and widely used in the range of 40 to 200 mm. The length of the tubular packaging film in the longitudinal direction is, for example, 50 to 400 mm, often 70 to 300 mm, and widely used in the range of 80 to 250 mm. Furthermore, the thickness of the tubular packaging film can be determined based on the film's strength and barrier properties, depending on the contents to be filled. For example, it is 15 to 300 μm, often 18 to 200 μm, and widely used in the range of 20 to 150 μm.

[0053] As the tubular packaging film, a heat-shrinkable film (uniaxially stretched film or biaxially stretched film) can also be used. Furthermore, to increase the strength of the tubular packaging film, improve its gas barrier properties, improve its heat resistance, adjust its shrinkage, etc., a laminated film can also be used. For example, a laminated film of the vinylidene chloride resin film of the present invention and another film such as polyethylene terephthalate film or polypropylene film can be used. Furthermore, the tubular packaging film can also be printed.

[0054] [Manufacturing of tubular packaging films]

[0055] The tubular packaging film of the present invention can be obtained by employing a conventional method for producing tubular packaging films for use in filled packaging bodies. Specifically, a strip of packaging film is rolled into a tubular shape with both side edges extending in the longitudinal direction overlapping to form a tubular film. Subsequently, the side edges of the tubular film are longitudinally sealed to form the tubular packaging film.

[0056] [Manufacturing of strip-shaped packaging films]

[0057] The method for producing a strip-shaped packaging film used to form a tubular packaging film is not particularly limited. For example, a sheet or tubular extruded film can be produced by extrusion molding. After stretching and imparting heat shrinkage as needed, the inner sides of a tubular extruded film can be overlapped to form two overlapping strips of packaging film having a predetermined width. The film can then be cut in the longitudinal direction as needed to produce a strip-shaped packaging film having a desired width. If the tubular packaging film is a laminated film, the laminated strip-shaped packaging film can be produced by coextrusion molding or extrusion lamination, or by bonding multiple films together using an adhesive, such as a urethane adhesive. If printing is intended for the tubular packaging film, the resulting strip-shaped packaging film can also be printed.

[0058] [Longitudinal sealing portion extending in the longitudinal direction]

[0059] The tubular packaging film of the filling package of one embodiment of the present invention is provided with a longitudinal sealing portion extending in the longitudinal direction. The longitudinal sealing portion is provided for the same purpose as the longitudinal sealing portion extending in the longitudinal direction of the tubular packaging film provided in the past. That is, a strip-shaped packaging film is rolled into a tubular shape in such a manner that the two side edges extending in the longitudinal direction overlap to form a tubular film. Then, the two side edges of the tubular film are continuously sealed (bonded) in the longitudinal direction (longitudinal direction) by conventional methods such as welding achieved by high-frequency dielectric heating, ultrasonic heating, laser heating, resistance heating, etc., or bonding achieved by an adhesive (including heat sealing), thereby forming a tubular packaging film. The longitudinal sealing portion is provided across the entire length of the tubular packaging film in the longitudinal direction, thereby enabling the contents filled and sealed in the tubular packaging film to be preserved in a sealed state. The width of the longitudinal sealing portion extending in the longitudinal direction of the tubular packaging film can be appropriately set.

[0060] [Convergence of both ends in the longitudinal direction]

[0061] A filling package according to one embodiment of the present invention includes a tubular packaging film having a longitudinal sealing portion extending in the longitudinal direction, with both ends of the longitudinal direction being gathered. Specifically, the filling package according to one embodiment of the present invention is formed by gathering the tubular packaging film at both ends of the longitudinal direction after filling the tubular packaging film with contents such as a processed food containing lipids, thereby preserving the contents in a sealed state. The gathering of the longitudinal ends of the tubular packaging film can be achieved by conventional methods for gathering the longitudinal ends of tubular packaging films included in filling packages, such as by using metal wire clamps such as aluminum wire clamps, transverse sealing films, or other means.

[0062] 2. The contents filled and sealed in the cylindrical packaging film

[0063] The content provided in the filled package body according to one embodiment of the present invention and filled and sealed in the cylindrical packaging film is not particularly limited, and may include, for example, lipids, as described above.

[0064] 3. Fill the packaging

[0065] A filled package according to one embodiment of the present invention is formed by filling and sealing a content in a cylindrical packaging film having a longitudinally extending seal portion and constricted at both ends in the longitudinal direction. The packaging film comprises the resin film of the present invention. The packaging film may also be composed of the resin film of the present invention. The shape and size of the filled package are generally determined by the shape and size of the cylindrical packaging film.

[0066] 4. Manufacturing method of filled packaging body

[0067] A method for manufacturing a filled packaging body according to one embodiment of the present invention is not particularly limited as long as a filled packaging body can be obtained. The filled packaging body is formed by filling and sealing a content into a tubular packaging film having a longitudinal seal extending in the longitudinal direction and having both ends thereof gathered in the longitudinal direction, wherein the tubular packaging film comprises the resin film of the present invention. Examples of such a manufacturing method include a method for manufacturing a filled packaging body comprising the following steps: a tubular film forming step of rolling a strip of packaging film into a tubular shape so that both side edges extending in the longitudinal direction overlap to form a tubular film; a longitudinal sealing step of longitudinally sealing both side edges of the tubular film to form a tubular packaging film having longitudinal seals extending in the longitudinal direction; a filling step of filling the tubular packaging film with the content; and an end gathering step of gathering both ends of the tubular packaging film in the longitudinal direction.

[0068] [Cylindrical film forming process]

[0069] A strip of packaging film is rolled into a roll with its longitudinally extending side edges overlapping to form a cylindrical film. The strip of packaging film can be manufactured according to the method described above. For example, the side edges can overlap along the outer peripheral surface perpendicular to the longitudinal direction of the strip of packaging film. Alternatively, the cylindrical film can be formed so that the side edges overlap and rise from the outer peripheral surface, as desired.

[0070] [Longitudinal Sealing Process]

[0071] The side edges of the tubular film are longitudinally sealed to form a tubular packaging film having longitudinally sealed portions extending in the longitudinal direction. Specifically, the side edges of the tubular film formed of the strip-shaped packaging film, which overlap and extend in the longitudinal direction, are longitudinally sealed continuously over a predetermined width extending in the longitudinal direction, thereby forming longitudinally sealed portions extending in the longitudinal direction.

[0072] The method for performing longitudinal sealing can adopt conventional methods such as welding achieved by high-frequency dielectric heating, ultrasonic heating, laser heating, resistance heating, etc., and bonding achieved by adhesives (including heat sealing). The cylindrical packaging film contains a polyvinylidene chloride resin as a polar resin. Therefore, from the perspectives of the efficiency of longitudinal sealing and the ease of adjusting the sealing strength, longitudinal sealing achieved by high-frequency dielectric heating is preferred. Specifically, while the two side edges extending in the long dimension of the tubular film are advanced, the film is passed between the sealing electrode and the ground electrode of the high-frequency dielectric heating device. By supplying high-frequency power between the two electrodes, a continuous longitudinal seal achieved by high-frequency welding is formed on the overlapping two side edges of the tubular film.

[0073] 〔Filling process〕

[0074] The tubular packaging film obtained through the longitudinal sealing process is filled with the contents. Specifically, the tubular packaging film is advanced, for example, from top to bottom at a predetermined speed, while the contents are continuously supplied to the opening of the tubular packaging film through a nozzle of a filling device equipped with a pump and a nozzle. The filling device and the guide mechanism for advancing the tubular packaging film can be appropriately selected from known mechanisms. The speed at which the tubular packaging film advances and the filling speed of the contents can be appropriately selected within conventional ranges.

[0075] [End-bundling process]

[0076] By converging both ends of a tubular packaging film filled with contents in the longitudinal direction, a filled package body can be obtained, in which the contents are filled and sealed in the tubular packaging film. Specifically, while the tubular packaging film filled with contents is advanced, a pressing device, such as a pair of rollers, is used to form a portion of the tubular packaging film where the contents are not present, below a position corresponding to the lower end and above a position corresponding to the upper end of the filled package body according to one embodiment of the present invention. The upper and lower ends of the portion where the contents are not present are converging, thereby forming the lower and upper ends of the filled package body according to one embodiment of the present invention. The portion is then cut to a predetermined length to obtain the filled package body according to one embodiment of the present invention. In the end converging step, conventional methods for converging both ends of the tubular packaging film in the longitudinal direction of the filled package body can be used, such as using metal clamps such as aluminum clamps, transverse sealing films, or other converging methods.

[0077] Example

[0078] The present invention will be further described below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[0079] [Example 1]

[0080] (Manufacturing of base film)

[0081] A copolymer (85 parts by mass) obtained by polymerizing vinylidene chloride (VD) and vinyl chloride (VC) at a monomer charge mass ratio (VD / VC) of 81 / 19 and a polymerization time of 38 hours was mixed with a copolymer (15 parts by mass) obtained by polymerizing vinylidene chloride (VD) and vinyl chloride (VC) at a monomer charge mass ratio (VD / VC) of 71 / 29 and a polymerization time of 37 hours to obtain 100 parts by mass of a copolymer mixture. To this 100 parts by mass of the copolymer mixture was added 5.4 parts by mass in total of dibutyl sebacate (DBS) and epoxidized vegetable oil, and further added 1.7 parts by mass in total of an epoxy group-containing polymer, an antioxidant, a surfactant, erucamide, calcium carbonate, and a colorant (Tango). Furthermore, an ultra-low density polyethylene (manufactured by TOSOH, trade name: LUMITAC 22-6, density 0.900 g / cm 3 ) 2.5 parts by mass to obtain a vinylidene chloride resin composition. Next, the obtained vinylidene chloride resin composition was melt-extruded using an extruder screw having a diameter of 40 mm, and then subjected to inflation biaxial stretching with an MD (long dimension) of 2.4 times and a TD (short dimension) of 4.0 times. The inner sides of the annular films were overlapped to obtain a strip-shaped vinylidene chloride resin film a having a thickness of 40 μm (the thickness of two films having a thickness of 20 μm) as a base film.

[0082] (Manufacturing of filled packaging)

[0083] While cutting the vinylidene chloride resin film a into a 65 mm width and performing high-frequency dielectric heating sealing to form a cylindrical shape, an automatic filling and packaging machine (manufactured by KUREHA, trade name: KAP3000 automatic filling and packaging machine) is used to fill the film with lipid-containing contents (a paste containing 52 mass% pork, 21.5 mass% ice water, 20 mass% pig fat, 5 mass% corn starch, 1.4 mass% salt, 0.05 mass% sodium tripolyphosphate, 0.04 mass% sodium ascorbate, and 0.01 mass% sodium nitrite), the ends of the film are bundled, and the portion clamped with the vinylidene chloride resin tape is sealed by ultrasonic sealing to obtain a filled package body (hereinafter also referred to as "filled package body before pressurized heat sterilization"). The tubular base film was adjusted to a folded width (half the circumference) of 28 mm, a cut length (measured in the longitudinal direction after removing the contents from the tubular package and flattening the tubular base film) of 190 mm, and a mass of 35 g. The filled package was then retorted (retorted) in hot water at 120°C under 0.2 MPa for 10 minutes to obtain a retorted filled package.

[0084] [Example 2]

[0085] In Example 1, an ionomer resin (manufactured by Dow, trade name: Surlyn 1707, a sodium ion neutralized product of an ethylene-methacrylic acid copolymer, density 0.95 g / cm 3 ) was used instead of ultra-low density polyethylene. Except for this, film b was obtained as the base film in the same manner as in Example 1, and filled packaging bodies before and after pressure heat sterilization were further obtained.

[0086] [Comparative Example 1]

[0087] Film c was obtained as a base film in the same manner as in Example 1 except that no ultra-low density polyethylene was added, and filled packaging bodies before and after retort sterilization were obtained.

[0088] <Measurement Method>

[0089] 〔Oxygen permeability〕

[0090] Before retort sterilization

[0091] Masking treatment (area 12.56 cm) was performed on the vinylidene chloride resin film. 2 (2cm×2cm×3.14)) and measured.

[0092] After pressure heat sterilization (retorting)

[0093] The vinylidene chloride resin film was peeled off from the filled package (content: sausage) and masked (area 12.56 cm 2 ) and measured.

[0094] Measuring instrument: Oxygen transmission rate measuring instrument OXTRAN 2 / 21 manufactured by MOCON.

[0095] ·Measurement temperature and humidity: 23℃, dry.

[0096] 〔Heat shrinkage〕

[0097] A 5 cm x 5 cm piece of vinylidene chloride resin film was cut, secured to a hanging fixture, and placed in a Geer oven set to 120°C. The film was then heated for 5 minutes while rotating the hanging fixture, and removed. After cooling to approximately 23°C, the MD (long dimension) Dcm and TD (short dimension) Ecm were measured, and the shrinkage ratio was calculated using the following formula.

[0098] MD thermal shrinkage (%): (1-D / 5)×100

[0099] TD thermal shrinkage (%): (1-E / 5)×100

[0100] 〔Fading Change〕

[0101] Immediately after retort sterilization (retort treatment) and after storage at 23°C for one month, the base film was peeled off from the filled package and the color and flavor of the sausages were compared. A relatively small change from red to brown was rated as 0, and a relatively large change was rated as ×.

[0102] [Table 1]

[0103]

[0104]

[0105] Calculation of the content (mass %) of the blended resin:

[0106] 2.5 / (85+15+5.4+1.7+2.5)×100=2.28≈2.3

[0107] It should be noted that in the table, the blended resin refers to the ultra-low density polyethylene in Example 1 and the ionomer resin in Example 2.

[0108] Example 1, in which ultra-low-density polyethylene was added, showed a smaller change in oxygen permeability than Comparative Example 1. In Example 2, in which an ionomer resin was added, the oxygen permeability after retorting (B) was lower than the oxygen permeability before retorting (A), indicating improved barrier properties. The reason for this is not entirely clear, but it is believed that the ionomer resin absorbs lipids in the contents, inhibiting their diffusion into the vinylidene chloride resin and promoting crystallization of the vinylidene chloride resin.

Claims

1. A vinylidene chloride resin film comprising a vinylidene chloride resin and a resin other than the vinylidene chloride resin, The vinylidene chloride resin film is a film in which the resin other than the vinylidene chloride resin contains at least one resin selected from the group consisting of ultra-low density polyethylene and ionomer resins, wherein: A content containing 20% by mass of lipids is filled and sealed in a tubular vinylidene chloride resin film having both ends in the longitudinal direction converged to form a filled package, and the filled package is subjected to pressure heat sterilization in hot water at 120°C under 0.2 MPa for 10 minutes. When the oxygen permeability converted to a thickness of 40 μm of the vinylidene chloride resin film before the pressure heat sterilization is defined as A and the oxygen permeability converted to a thickness of 40 μm of the vinylidene chloride resin film after the pressure heat sterilization is defined as B, the rate of change in oxygen permeability calculated as (B-A) / A×100 is 35.0% or less, where the unit of A is cm 3 / m 2 ·day·atm, the unit of B is cm 3 / m 2 ·day·atm.

2. The vinylidene chloride resin film according to claim 1, wherein The change rate of the oxygen permeability is 1.5% or less.

3. The vinylidene chloride resin film according to claim 1, wherein The change rate of the oxygen permeability is greater than -10.0%.

4. The vinylidene chloride resin film according to claim 1, wherein The change rate of the oxygen permeability is greater than -8.0%. The vinylidene chloride resin film according to claim 1 , wherein In the vinylidene chloride resin film, the content of the resin other than the vinylidene chloride resin is 0.5% by mass or more and less than 3% by mass. The vinylidene chloride resin film according to claim 1 , wherein The vinylidene chloride resin is a copolymer of 60% by mass or more and 95% by mass or less of vinylidene chloride and 5% by mass or more and 40% by mass or less of vinyl chloride. 7 . A filled package comprising the vinylidene chloride resin film according to claim 1 and a content.

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