JP2014181076A - Slice cheese packaging film, and individual package - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slice cheese packaging film capable of performing a thermal adhesion at a low temperature and excellent in body separability, and an individual package packaging slice cheese with the film.SOLUTION: A slice cheese packaging film 1 having a thermal adhesion layer 4 formed directly or indirectly on at least one face of a base material film 2 and made of a saturated copolymer polyester resin. The thermal adhesion layer 4 is formed of two kinds of saturated copolymer polyester resin different in a glass transformation temperature. To the thermal adhesion layer 4, moreover, a mold-releasing agent is used by adding a compound of one kind or more selected from sucrose fatty acid ester, lecithin, glycerine fatty acid ester, sorbitan fatty acid ester, stearate, oleate ester and condensation ricinoleic acid ester.

Description

  The present invention relates to a film useful for packaging sliced cheese, and a package in which sliced cheese is packaged with this film.

  When wrapping sliced cheese with a film for individual packaging, it is necessary to bond the overlapping part (back pasting part) where both ends of the film overlap and both side parts of the film. These adhesions are carried out by thermal bonding (heat sealing). As a method for doing so, in recent years, from a method using a conventional metal heat sealing bar, a method in which high pressure and high temperature air is blown from a 1 to 3 mm hole to a film to perform thermal bonding. It is changing. When using a metal heat seal bar, there was a problem that the metal heat seal bar and the film were in close contact, and high-speed packaging was not possible due to frictional resistance. Since it is not received, high-speed packaging is possible as compared with a method using a metal heat seal bar, and therefore, a method of blowing high-pressure and high-temperature air is becoming mainstream.

  As the method of spraying this high-pressure and high-temperature air is generalized, a characteristic that thermal bonding at a lower temperature than before is required for a sliced cheese film.

  Furthermore, sliced cheese is prepared by forming high-temperature cheese into a sheet on a film and cooling it. After cooling, when the packaging film is peeled off, the surface layer of cheese peels off at the same time as the packaging film, resulting in commercial value. May be damaged. Therefore, there is also a demand for the property that heat bonding at a low temperature is possible, and at the same time, the film has excellent releasability and the surface layer of cheese does not peel off when opened (excellent releasability).

  As a film (inner film) for directly packaging conventional sliced cheese, a plastic film or a plastic film having a cheese contact surface subjected to a release coating treatment is used. Japanese Patent Laid-Open No. 58-78757 discloses that a polyvinylidene chloride layer and a rubber-wax film layer are sequentially formed on the surface of a base film, and an antiblocking agent is formed in the rubber-wax film. A cheese packaging material in which is partially embedded is disclosed. In JP-A-57-57661, a vinylidene chloride resin layer is formed on one side of a base film, and a slippery and water-repellent layer containing wax, inorganic fine powder and a binder is formed on the opposite side. A sliced cheese cheese dressing film is disclosed. Japanese Utility Model Laid-Open No. 2-106442 discloses a slice cheese piece in which one surface of a base film is covered with a heat-adhesive coating layer containing a wax, a fine powder lubricant and a binder resin. A wear film is disclosed. Further, JP-A-9-40012 discloses a film in which a heat-adhesive layer is formed directly or indirectly on at least one surface of a base film. Further, JP-A-2006-232345 includes a base film composed of a heat-sealable layer and a polyhydric alcohol fatty acid ester containing at least a sucrose fatty acid ester formed on the surface of the layer, and A film composed of a coating layer that does not contain sodium lauryl sulfate is disclosed.

  However, these films are not necessarily suitable for thermal bonding at a low temperature of around 100 ° C., so that the thermal bonding strength at a low temperature is insufficient. Accordingly, there has been a demand for the development of a sliced cheese packaging film that has sufficient thermal adhesive strength at low temperatures and is excellent in releasability.

JP 58-78757 A JP-A-57-57661 Japanese Utility Model Publication No. 2-106442 Japanese Patent Laid-Open No. 9-40012 JP 2006-232345 A

  Accordingly, an object of the present invention is to provide a sliced cheese packaging film that can be thermally bonded at a lower temperature and has excellent detachability, and an individual package in which sliced cheese is packaged with this film.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that at least one surface of the substrate film includes a saturated copolyester resin having two glass transition temperatures on the low temperature side and the high temperature side. When the adhesive layer is formed directly or indirectly, sufficient adhesive strength is exhibited in the thermal adhesion between the thermal adhesive layers in the low temperature range, and the adhesive strength between the substrate and the thermal adhesive layer in the high temperature range. Found to improve. Furthermore, it has been found that an excellent release property can be obtained by adding a specific release agent to the heat-adhesive layer, and the present invention has been completed.

  That is, the slice cheese packaging film of the present invention is a film in which a heat-adhesive layer is formed directly or indirectly on at least one surface of a base film, and the heat-adhesive layer is a saturated copolymerized polyester resin. It is characterized by being. The heat-adhesive layer may contain, for example, two types of saturated copolyester resins having different glass transition temperatures. In the thermal adhesive layer, the saturated copolyester resin used for the thermal adhesive layer may have two glass transition temperatures. The base film may be a polyester film.

  The heat-adhesive layer can be heat-bonded to the base film at 100 ° C., and the peel strength of the film with respect to cheese measured using a tensile tester may be 3 g / 15 mm or less. The peel strength is measured using a tensile tester. The heat seal strength of the heat-adhesive layer with respect to the base film may be 10 to 100 g / 15 mm. The thermal adhesive layer may contain a release agent. As the mold release agent, one or more compounds selected from sucrose fatty acid ester, lecithin, glycerin fatty acid ester, stearic acid ester, oleic acid ester, and condensed ricinoleic acid ester may be used. The release agent may be contained in the heat-adhesive layer in an amount of 0.5% by weight to 3.0% by weight.

  In the present invention, the heat-adhesive layer of the sliced cheese packaging film is in close contact with the sliced cheese, the overlapping part where the both ends of the film overlap (the back pasting part), and the slice where the films are bonded to both sides of the film A sliced cheese wrapped with cheese is also included.

  In the present invention, by directly or indirectly forming a heat-adhesive layer containing a saturated copolymerized polyester resin having two glass transition temperatures on the low temperature side and the high temperature side on at least one surface of the base film. In addition, sufficient adhesive strength can be obtained in the thermal bonding between the heat-adhesive layers in the low temperature region, and the adhesive strength between the substrate and the heat-adhesive layer is improved in the high temperature region. Furthermore, the excellent separability can be obtained by adding a specific release agent to the heat-adhesive layer.

  FIG. 1 is a schematic view showing a sliced cheese individual package packaged with a film which is an example of the present invention.   FIG. 2 is a schematic cross-sectional view taken along the line AB of the sliced cheese individual package wrapped with the film which is an example of the present invention shown in FIG.   FIG. 3 is a schematic view showing a cut position of a sliced cheese individual body cut to a width of 15 mm to make an evaluation sample in the evaluation of releasability according to the present invention.   FIG. 4 is a schematic diagram showing the cutting position of an evaluation sample in which the film is folded in half and both ends are heat-sealed and cut into a length of 5 cm and a width of 15 mm in the evaluation of the thermal adhesive strength of the present invention. It is.

DESCRIPTION OF SYMBOLS 1 ... Film for slice cheese packaging 2 ... Base film 3 ... Undercoat layer 4 ... Thermal adhesive layer 5 ... Slice cheese 6 ... Thermal adhesive part (back pasting part)
7 ... Thermal bonding part (both ends of film)
8 ... Cut line

  Hereinafter, the present invention will be described in detail with reference to the drawings as necessary.

  FIG. 1 is a schematic view showing an individual package in which sliced cheese is packaged with a sliced cheese packaging film as an example of the present invention, and FIG. 2 is a conceptual diagram showing a cross section of FIG. The packaging film 1 for closely packaging the sliced cheese 5 is a base film 2 and a heat-adhesive layer (heat seal layer) sequentially formed over the entire surface of at least one side of the base film 2. 4. The thermal adhesive layer 4 is firmly adhered to the base film 2. Further, the thermal adhesive layer 4 has excellent releasability (peelability) with respect to cheese. In addition, an undercoat layer (anchor layer) 3 may be present between the thermal adhesive layer 4 and the base film 2.

[Base film]
Examples of the base film 2 include various films for packaging, such as polyolefin films (for example, polyethylene films and polypropylene films); polystyrene films (for example, polystyrene films); polyester films (for example, polyethylene terephthalate films). Polyamide film; Polyvinyl alcohol (PVA) film; Polyvinyl chloride film; Polyvinylidene chloride (PVDC) film; Fluororesin film; Cellulose film (for example, cellulose acetate film); Polycarbonate film Etc. can be used. A polyester film is mentioned as a preferable base film in these. In addition, these base film may be a single layer film or a composite film. Further, the base film may be an unstretched film or a uniaxial or biaxially stretched film.

  The thickness of the base film 2 can be selected within a range that does not impair the close packaging property of the sliced cheese 5, for example, 1 to 100 μm, preferably 5 to 50 μm, more preferably 10 to 40 μm, and further preferably 10 to 25 μm. is there.

[Thermal adhesive layer]
The heat adhesive layer of the present invention is formed of a saturated copolymerized polyester resin. The saturated copolyester resin used for the heat-adhesive layer is preferably a saturated copolyester resin having two glass transition temperatures on the low temperature side and the high temperature side. A method for producing a saturated copolyester resin having two glass transition temperatures is generally produced by blending two types of saturated copolyester resins having different glass transition temperatures. But it doesn't matter.

  The saturated copolyester resin used in the present invention is not particularly limited, and a plurality of commercially available saturated copolyester resins can be used in combination.

  The thermal adhesive layer only needs to be formed on at least one surface of the base film. For example, the thermal adhesive layer may be formed on one surface of the base film, and on both surfaces of the base film. A thermal adhesive layer may be formed. Moreover, a heat adhesive layer may be formed indirectly through an undercoat layer, and may be directly formed with respect to a base film. Although it is a method of forming a heat-adhesive layer on a substrate film, it can be carried out by a conventional coating method or lamination method (for example, extrusion lamination, dry lamination, hot melt lamination, wet lamination method, etc.). The undercoat layer and the heat-adhesive layer may be formed by sequentially applying and drying a coating solution containing components corresponding to the undercoat layer and the heat-adhesive layer on a base film.

[Release agent]
The thermal adhesive layer of the present invention may contain a release agent. The release agent is not particularly limited as long as it can be added to the heat-adhesive layer without impairing the heat-adhesive property of the heat-adhesive layer and imparting the ability to release the film (release property) to cheese. For example, wax, higher fatty acid amide, higher fatty acid or derivatives thereof, silicone oil, and the like can be raised. In many cases, the release agent excluding silicone oil is solid at room temperature. Examples of the wax include petroleum waxes such as paraffin wax, microcrystalline wax, and petrolatum; plant waxes such as carnauba wax, cotton wax, tree wax, and sugar wax; animal waxes such as beeswax, wool wax, whale wax, and insect wax; Examples thereof include mineral waxes such as ozokerite; synthetic waxes such as polyethylene wax. The wax may be any of hydrocarbon, fatty acid, fatty acid amide, and ester. Examples of higher fatty acid amides include oleic acid amide, stearic acid amide, methylene bis stearic acid amide, and higher fatty acids or derivatives thereof include higher fatty acids such as stearic acid, higher fatty acids such as methyl stearate and stearic acid triglyceride. Examples thereof include higher fatty acid metal salts such as esters and zinc stearate. These release agents can be used alone or in combination.

  Preferred release agents include highly safe substances that exhibit high releasability when added in small amounts, for example, waxes such as plant-based, animal-based, petroleum-based or synthetic waxes, and higher fatty acids such as higher fatty acid glycerides. Esters are included. When petroleum-based wax is used, paraffin wax having 16 to 40 carbon atoms, preferably about 20 to 30 is often used, and the melting point of paraffin wax is, for example, about 35 to 65 ° C.

  Further, more preferable release agents include higher fatty acid esters, and among the higher fatty acid esters, sucrose fatty acid ester, lecithin, glycerin fatty acid ester, sorbitan fatty acid ester, stearic acid ester, oleic acid ester, condensation Ricinoleic acid esters are suitable for use in the present invention. These higher fatty acid esters may be used alone or in combination.

  The amount of the release agent added is, for example, 0.1 to 15% by weight, preferably 0.5 to 10% by weight, more preferably 0 in the heat-adhesive layer, with respect to the total amount of components constituting the heat-adhesive layer. About 5% by weight to 3.0% by weight. The release agent is used as it is or in a form dissolved in a solvent and added to a constituent of the coating liquid or laminate composition corresponding to the heat-adhesive layer.

  Furthermore, the sliced cheese packaging film of the present invention may have various coating layers such as slipperiness and antistatic layer as necessary.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
On one side of a polyethylene terephthalate film (thickness 16 μm) as a base film, 50 parts by weight of two types of saturated copolymer polyester resins having different melting points and molecular weights and 1 part by weight of a release agent are mixed and dissolved in a solvent. Then, it was applied to a dry weight of 2.0 g / m 2 and dried at 50 ° C. for 1 hour to produce a sliced cheese packaging film having a heat-adhesive layer (heat seal layer) on one side.

Comparative Example 1
A dry weight of 2.0 g / m2 is obtained by dissolving a vinylidene chloride resin (manufactured by Asahi Kasei Corporation; PVDC latex L-509) in a solvent on one side of a polyethylene terephthalate film (thickness 15 μm) as a base film. The slice cheese packaging film having a heat-adhesive layer (heat seal layer) on one side was produced.

[Evaluation of releasability]
Evaluation of releasability of the sliced cheese packaging film was performed by the following method.
(1) Cut the film of Example and Comparative Example into a size of 250 mm × 100 mm.
(2) The commercially available sliced cheese (Meiji Dairies Co., Ltd .; trade name: Tokachi cheese) stored in the refrigerator is taken out of the packaging film and packaged again using the films of Examples and Comparative Examples. After packaging, both ends of the packaged film are heat-sealed to a width of 5 mm under the conditions of a load of 1 kg, a temperature of 100 ° C., and a time of 1 second.
(3) The packaged sliced cheese individual body is put in an oven and heated at 70 ° C. for 3 minutes.
(4) The sliced cheese individual package heated to 70 ° C. is left in a thermostatic chamber at 23 ° C. and 60% RH for one hour.
(5) Take out the sliced cheese individually left in a constant temperature and humidity chamber at 23 ° C. and 60% RH for 1 hour and cut it into a width of 15 mm. (See Figure 3)
(6) The back-pasted part seal part of the sliced cheese individual body cut into a width of 15 mm is peeled off by hand, and a load is applied to the peeled film end under the condition of a pulling speed of 300 mm / min using a tensile tester. The force required for the film to peel from the cheese is measured. Furthermore, it is observed visually whether cheese has adhered to the peeled film.
The results are shown in Table 1.

[Evaluation of thermal bond strength]
Evaluation of the thermal adhesive strength at low temperature of the sliced cheese packaging film was performed without sandwiching the cheese between the films as shown below. This is because when cheese is sandwiched between films, a small amount of cheese is also present between the films of the heat seal portion, and the thermal bond strength value varies.
(1) Cut the film of Example and Comparative Example into a size of 250 mm × 100 mm.
(2) Fold the film as when wrapping sliced cheese, but without sandwiching the cheese.
(3) The both ends of the folded film are heat-sealed to a width of 1 cm under the conditions of a load of 1 kg, a temperature of 100 ° C. or 160 ° C., and a time of 1 second.
(4) The film is cut to a length of 5 cm and a width of 15 mm with the heat seal portion at the top. (See Figure 4)
(5) The opposite side of the heat seal part of the film cut to a length of 5 cm and a width of 15 mm is set in a tensile tester, and the peel strength (g / 15 mm) is measured under the condition of a tensile speed of 300 mm / min.
The results are shown in Table 1.

表１に示されるように、実施例のフィルムを用いると、１００℃の低温度ヒートシールでも、十分な接着強度が得られ、且つ、フィルムを剥がしてスライスチーズを取り出す際に、フィルムにスライスチーズが殆ど付着しない優れた離型性が得られる。

As shown in Table 1, when the film of the example is used, sufficient adhesive strength can be obtained even at a low temperature heat seal of 100 ° C., and when the sliced cheese is taken out by peeling the film, the sliced cheese is added to the film. Excellent releasability with almost no adhesion is obtained.

  The film for wrapping sliced cheese of the present invention is suitable for wrapping sliced cheese, and sheet heel by a method of blowing high-pressure and high-temperature air is possible.

Claims (10)

  For sliced cheese packaging, wherein a thermal adhesive layer is formed directly or indirectly on at least one surface of a base film, and the thermal adhesive layer is a saturated copolymerized polyester resin the film.   The slice cheese packaging film according to claim 1, wherein the heat-adhesive layer is formed of two types of saturated copolyester resins having different glass transition temperatures.   The slice cheese packaging film according to claim 1 or 2, wherein the saturated copolyester resin used in the heat-adhesive layer has two glass transition temperatures.   The slice cheese packaging film according to any one of claims 1 to 3, wherein a polyester film is used as the base film.   The thermal adhesive layer can be thermally bonded to the base film at 100 ° C, and the peel strength of the film with respect to cheese measured using a tensile tester is 3 g / 15 mm or less. The sliced cheese packaging film described in the item.   The film for slicing cheese packaging according to any one of claims 1 to 5, wherein the heat-sealing strength of the heat-adhesive layer with respect to the base film is 10 to 100 g / 15 mm.   The slice cheese packaging film according to any one of claims 1 to 6, wherein the thermal adhesive layer contains a release agent.   Any one or more types of compounds chosen from a sucrose fatty acid ester, a lecithin, a glycerin fatty acid ester, a sorbitan fatty acid ester, a stearic acid ester, an oleic acid ester, and condensed ricinoleic acid ester as a mold release agent are used. The sliced cheese packaging film described in the above item.   The film for sliced cheese packaging according to any one of claims 1 to 8, wherein the release agent is contained in the heat-adhesive layer in an amount of 0.5 to 3.0% by weight.   The heat-adhesive layer of the film according to any one of claims 1 to 9 is in close contact with the sliced cheese, and a polymerized portion (back pasting portion) where both ends of the film overlap and a side portion of the film are thermally bonded. A sliced cheese piece.

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