JP4156270B2 - Interior film for oxygen scavenging packaging - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a deoxygenating package in a packaging format in which an oxygen scavenger and contents individually packaged are stored in an outer bag and sealed, and particularly relates to a material of an inner film used as an individual package.
[0002]
[Prior art]
About 21% oxygen is present in the air, but if the sealed package can be maintained in an oxygen-free state, it will prevent mold, oxidative deterioration, discoloration, and insects from entering the package. This protects the nutrition, freshness, flavor, and medicinal properties of food, medicine and pharmaceuticals. Conventionally, a packaging technique such as a gas pack that replaces air to be filled with an inert gas such as nitrogen or carbon dioxide during vacuum packaging or hermetic packaging has been performed.
Recently, deoxygenation packaging techniques have been widely used for the purpose of preserving the contents of foods.
At present, when performing oxygen scavenging packaging, there are many cases in which a gas barrier packaging material is used for the exterior, and the interior of each content (hereinafter referred to as individual packaging) is not used, or the packaging is not sealed.
In this case, when the exterior is opened, the contents are immediately oxidized, and mold and rot occur, making edible.
Therefore, in the oxygen scavenging packaging, as shown in FIG. 2, a method of storing the contents K sealed in the interior bag 2 and hermetically sealed together with the oxygen scavenger 4 in the outer bag 3 having gas barrier properties is performed.
Packaging the contents K individually is a double wrapping because the contents K after opening the outer bag 3 and taking out a part thereof are contaminated with bacteria and dust, This is to prevent alteration and the like due to adsorption / desorption, but during the period until the exterior bag is opened, oxygen in the air enclosed in the interior bag inner space 2S of the interior bag 2 is transferred from the interior bag 2 to the exterior bag 3. It is necessary to be permeated into the outer bag inner space 3S and absorbed by the oxygen scavenger 4, and as an interior film used for individual packaging, a film having oxygen permeability is required.
[0003]
[Problems to be solved by the invention]
In deoxygenated packaging, the interior film used when individually wrapping the contents K has a function of protecting the contents after the exterior is opened, for example, the contents absorb moisture or the contained moisture dehydrates. There is a need for a film that can prevent moisture and water resistance, and prevent bacterial adhesion and insect contact.
As a specific example, in deoxygenated packaging of chopped rice cake, the cutting candy generates mold and yeast in the presence of oxygen. Therefore, recently, by cutting and sachet and oxygen scavenger in a gas barrier outer bag, the oxygen scavenger absorbs the free oxygen in the outer bag and keeps the scissors away from oxygen. It became possible to lengthen the period.
In the past, individual cut straws were either unwrapped or unsealed, and the packaging conditions were such that oxygen on the surface of the straw was easily absorbed by the oxygen scavenger, but in this case, the packaging should not be used after opening the outer packaging. Since the remaining cocoons are easily moldy or rot, the cocoons packaged in the exterior body had to be consumed quickly after opening.
Moreover, as an interior film in deoxygenation packaging, a film having good packaging suitability for individual packaging is required. There has been a demand for a film having oxygen permeability that allows deoxygenation packaging, content protection after opening the exterior, and suitability for packaging machines in individual packaging.
Conventionally, when this type of packaging is performed, as a film for K interior, as shown in FIG. 4 (a), a laminate 30 ′ of a base material layer 31 ′ provided with special fine holes h and a heat seal layer 32 ′. In some cases, a laminated body 30 ″ of a base material layer 31 ″ and a heat seal 32 ″ made of a special film with high gas permeation may be used, but there are problems such as high distribution strength and high cost of drilling. there were.
In addition, the individually packaged contents K can be preserved after opening by performing external UV sterilization or gas sterilization in an individually packaged state before being stored in the outer bag 3 together with the oxygen scavenger 4. Therefore, a material suitable for these processing conditions has been desired.
It is an object of the present invention to prevent the contents from being oxidized, mold generation, etc., in a package that seals and seals the individually packaged contents and oxygen scavenger in a gas barrier outer bag, and opens the outer bag. Provided is an interior film for deoxygenated packaging that has the property of preventing the subsequent contents from drying or moisture absorption, can be sterilized by ultraviolet rays or gas after individual packaging, and has good suitability for packaging machinery in individual packaging. There is.
[0004]
[Means for Solving the Problems]
The present invention is a packaging bag in which an individual packaging bag containing contents and an oxygen scavenger are stored in an outer bag having gas barrier properties, and the film of the individual packaging bag has a thickness from the outside. A laminate film composed of an unstretched polypropylene film having a thickness of 15 to 50 μm and a linear low-density polyethylene resin layer having a thickness of 15 to 50 μm and a density of 0.89 to 0.917. It consists of an interior film for oxygen scavenging packaging. Further, the laminate film in which the individual packaging laminate film is formed by extrusion laminating a linear low density polyethylene resin on one surface of an unstretched polypropylene film coated with an anchor coating agent composed mainly of a polyolefin resin In addition, the laminate film of the individual packaging bag includes that the transmittance of ultraviolet light having a wavelength of 250 nm is 70% or more.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the package used for individual packaging is stored in an outer bag made of a film having a gas barrier property together with an oxygen scavenger and the outer bag is hermetically sealed. By using a laminate film with density polyethylene, it is possible to maintain the quality of the contents by deoxygenation packaging and to prevent the contents from being altered after opening the outer bag. Hereinafter, it will be described in more detail with reference to the drawings.
[0006]
FIG. 1 is a cross-sectional view of a film showing an example of the interior film for deoxidizing packaging of the present invention. FIG. 2 is a cross-sectional view illustrating the concept of deoxidation packaging. FIG. 3 is a film cross-sectional view showing an example of a film forming an outer bag for deoxygenation packaging.
[0007]
As a result of diligent research to solve the problems of the present invention, the present inventor used a base layer 21 made of an unstretched polypropylene film and a metallocene catalyst as an interior film for deoxygenated packaging as shown in FIG. It has been found that the above-mentioned problems can be solved by using a laminate 20 with a heat-seal layer 22 made of polymerized linear low-density polyethylene, and the present invention has been completed.
[0008]
The polypropylene resin used for the unstretched polypropylene film (hereinafter referred to as CPP) used as the base material layer 21 of the interior film 20 for deoxygenated packaging of the present invention may be a homotype (hereinafter referred to as homoCPP) or a copolymer type with ethylene (hereinafter referred to as “homo CPP”). Copoly CPP), which may be a non-anchor type that does not require a coating of an anchor coating agent in laminating. The thickness of the unstretched polypropylene film is suitably in the range of 15 to 50 μm. When the thickness of the unstretched polypropylene film is less than 15 μm, the laminating suitability is lowered, and when the thickness of the unstretched polypropylene film exceeds 50 μm, the oxygen gas permeability is lowered, and desirable oxygen permeation as an interior film for deoxygenated packaging. Is difficult to obtain.
In the present invention, linear low density polyethylene is laminated on these CPPs to form an interior film 20 for deoxygenated packaging, but when linear low density polyethylene is laminated on CPPs, in order to stabilize the laminate strength It is desirable that CPP is coated with an anchor coating agent and linear low density polyethylene is extrusion laminated. The linear low density polyethylene suitably has a thickness in the range of 15 to 50 μm and a density in the range of 0.89 to 0.917. If the thickness is less than 15 μm, the required heat seal strength is difficult to obtain, and if the thickness exceeds 50 μm, the oxygen permeability is lowered and deoxidation packaging becomes difficult. Further, when the density of the linear low density polyethylene is less than 0.89, film formation is difficult, and with the linear low density polyethylene having a density exceeding 0.917, the heat seal temperature in the case of individual packaging May become high and may damage CPP which is a base film.
When the interior film 20 for oxygen scavenging packaging of the present invention is deoxidized and packaged as a two-layer film of CPP and linear low density polyethylene, special processing such as micro-drilling is performed as the interior film. And can be used as a film having high oxygen permeability.
Moreover, since the base material layer 21 is made of CPP, the problem that the heat resistance is reduced as compared with the biaxially stretched film that is a conventional base material layer is that the heat seal layer is formed of a low-melting linear low-density polyethylene. It was possible to wrap the individual packaging without reducing the speed of the packaging machine.
[0009]
The oxygen permeability of the interior film for oxygen-removing packaging of the present invention was measured by JIS K7126 (MOCON method) as a material for dry conditions at 23 ° C.
In the laminate film of CPP 30 μm and linear low density polyethylene 30 μm, which is the structure of the present invention, it is about 3000 to 3500 cc / m ² · 24 hrs · atm), specially perforated biaxially stretched polypropylene film 20 μm and linear low density. It was almost the same level as 3200-3500 cc / m ² · 24 hrs · atm) at 40 μm in polyethylene.
[0010]
In the present invention, when applied to a packaging machine for individually packaging the interior film for deoxygenated packaging, the CPP of the present invention is formed as compared with a conventionally-made biaxially stretched polypropylene film having a special hole. The heat resistance of the polypropylene resin is reduced, but by using a linear low density polyethylene having a density of 0.89 to 0.917, the heat sealing temperature of the individual packaging machine is lowered, thereby reducing the heat sealing temperature of the CPP. Could avoid damage.
Conventionally, it was a laminate film of a two-layer structure of a special perforated polypropylene or polyester biaxially stretched film and the like and a low-density polyethylene resin layer. By using the unstretched polypropylene film to be used, by bonding CPP and a sealant made of linear low density polyethylene having an oxygen permeability of 5000 cc / m 2 · 24 hrs, the oxygen permeability is set to 3000 cc / m 2 · 24 hrs or more, Deoxygenation packaging within individual packaging is possible.
[0011]
The lamination method of the interior film for oxygen-removing packaging of the present invention may be any of an extrusion lamination method, a sandwich lamination method, a dry lamination method, etc., but is an extrusion lamination in which linear low density polyethylene is directly melt extruded into CPP. The method is desirable because the processing stability and manufacturing cost are low.
[0012]
When CPP for linear low density polyethylene is laminated by extrusion on CPP, linear low density polyethylene may be directly extruded and laminated without coating an anchor coating agent in CPP for multilayer anchors. When extrusion laminating a chain low density polyethylene, as shown in FIG. 1, in order to stabilize the laminate strength, an anchor coating agent AC is coated on the homo CPP 21 and the coated surface has a linear low density polyethylene. It is desirable to laminate by extrusion.
As a result of testing various types of anchor coating agents, the present inventor has shown that the coating strength composed of a resin mainly composed of polyolefin, particularly, the polyethyleneimine-based anchor coating agent has the most stable laminate strength.
In addition, there may be UV irradiation for surface sterilization of the individually wrapped contents,
In this case, the ultraviolet wavelength region having a bactericidal effect is around 250 nm,
A significant difference was observed in the ultraviolet transmission of the laminate film obtained depending on the type of anchor coating agent. In the laminate film using the polyethyleneimine-based anchor coating agent, the ultraviolet transmittance at the wavelength was 80% or more. In the laminated film using the organic titanium-based or isocyanate-based anchor coating agent, the ultraviolet transmittance at the same wavelength is as low as 50% or less, and the effect of sterilization by ultraviolet rays is inferior.
[0013]
In the interior film for oxygen scavenging packaging of the present invention, the individual packaging pouch type may be any type that can be hermetically packaged, and a three-side seal type, a four-side seal type, a pillow type, a blister type, or the like can be used.
[0014]
The film for forming the outer bag in the deoxidation packaging to which the inner film for deoxygenation packaging of the present invention is applied may be any material that can be hermetically packaged for use in ordinary deoxygenation packaging, for example, as shown in FIG. As shown in FIG. 3B, the intermediate layer between the base material layer 31 and the heat seal layer 32 as shown in FIG. 33 may be provided. And each said layer which comprises the film which forms the exterior bag 3 can be obtained by bonding together suitably using methods, such as a well-known dry lamination, T-die extrusion lamination, and sandwich lamination as needed.
The base material layer 31 is required to have excellent printability and laminate suitability, excellent overall mechanical strength such as tensile strength, impact strength, and scratch resistance, and heat resistance against heating during heat sealing. When the exterior bag 3 has a two-layer configuration of the base material layer 31 and the heat seal layer 32, it is necessary to select a film having gas barrier properties as the base material layer 31. For example, a biaxially stretched polyester film, a biaxially stretched nylon film, or a film coated with polyvinylidene chloride (PVDC) or the like to impart gas barrier properties to these films, or a metal such as aluminum, silicon oxide, What provided thin films, such as an alumina, by vacuum evaporation etc. can be used as a base material layer.
As the heat seal layer 32, a resin adapted to the heat seal conditions of the packaging machine used for the exterior, that is, a resin that is thermally bonded with sufficient strength by the heat and pressure of the heat seal bar of the packaging machine may be selected. For example, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ionomer, etc. Is used.
[0015]
The intermediate layer 33 when the outer bag 3 has a three-layer configuration in which the intermediate layer 33 is provided between the base material layer 31 and the heat seal layer 32 is used to improve the mechanical strength of the laminate film, Provided to improve various gas barrier properties, particularly oxygen barrier properties, depending on the purpose, for example, films such as nylon, polyvinyl alcohol, saponified ethylene-vinyl acetate copolymer (EVOH), aluminum foil, or A resin film having a surface coated with a thin film of aluminum, silicon oxide, alumina, or the like by vacuum deposition or the like can be used.
As an exterior bag used for deoxidation packaging to which the interior film 20 for deoxygenation packaging of the present invention is applied, the pouch type is not limited as long as hermetic packaging is possible. As with the individual packaging type, for example, a three-side seal, a four-side seal, a pillow pouch, or the like can be used.
[0016]
Examples of the contents that can be used for deoxygenation packaging using the interior film 20 for deoxygenation packaging of the present invention include cut castella, baumkuchen, madeleine, donuts, raw / half-boiled Japanese confectionery, medical / pharmaceutical products, etc. It is done.
[0017]
By storing the contents K individually wrapped with the interior film 20 for oxygen scavenging packaging of the present invention in the exterior bag 3 together with the oxygen scavenger 4, the oxygen scavenger 4 is sealed in the exterior bag inner space 3S. As the oxygen in the air is absorbed, the oxygen enclosed in the individual packaging inner space 2S permeates the deoxygenating packaging inner film 20 forming the individual packaging and diffuses into the outer bag inner space 3S to be removed. It is absorbed by the oxygen agent 4 and the inside of the individual package is maintained in an oxygen-free state. As a result, the contents K can be prevented from being deteriorated due to oxygen, such as oxidation, mold, and decay.
In addition, even after opening the outer bag 3, the contents K are sealed with the interior film 20 composed of CPP and linear low-density polyethylene, so that moisture transpiration from the contents K or moisture absorption from the outside air does not occur. Almost no long-term storage is possible.
In the packaging machine for individually packaging the contents K, the deoxidized packaging interior film 20 of the present invention is 30 times higher than the heat seal bar temperature of the conventional laminate film of biaxially oriented polypropylene film and low density polyethylene. Heat sealing was possible at temperatures as low as 0 ° C., the CPP film was not damaged by the hermetic seal, and the packaging speed was not reduced.
In addition, for the purpose of sterilizing the surface of the contents K, when sterilization is performed by irradiating ultraviolet rays in a state where the contents K are individually packaged, the anchor coating agent for producing the deoxidized packaging interior film 20 of the present invention By using a polyethyleneimine-based coating agent as AC, the transmittance of ultraviolet rays around 250 nm, which is an ultraviolet wavelength region showing a bactericidal effect, is 80% or more, and an excellent bactericidal effect as compared with other anchor coating agents. Could get.
[0018]
【Example】
The interior film for deoxygenating packaging of the present invention will be described with reference to examples.
[Example 1]
An imine anchor coat was applied to a homotype polypropylene film (thickness 30 μm), and linear low-density polyethylene (density 0.91, thickness 30 μm) was extrusion laminated to obtain Example 1.
[Example 2]
A non-anchor multilayer type polypropylene film (PE / homotype PP / co-polytype PP thickness 30 μm) is extrusion-laminated with a linear low density polyethylene (density 0.91, thickness 30 μm) without anchor coating. Example 2 was adopted.
[0019]
[Comparative Example 1]
A highly breathable stretched polypropylene film (thickness 20 μm) and a low density polyethylene film (density 0.92, thickness 40 μm) were dry laminated to obtain Comparative Example 1.
[0020]
<Evaluation method>
1) Measurement of gas barrier oxygen permeability (JIS K7126)
2) Measurement of UV germicidal UV transmittance (Spectrophotometer UV-2400, Shimadzu Corporation)
3) Heat sealability Each sample of the examples and comparative examples was tested for heat sealability (relationship between temperature and seal strength).
[0021]
<Result>
[0022]
1) Oxygen permeability (unit: cc / m ² · 24 hrs)
The oxygen permeability was comparable to that of a laminate film using a conventional specially breathable biaxially oriented polypropylene film.
Example 1 2965
Example 2 3273
Comparative Example 1 3320
2) UV transmittance (unit:%)
Both Example 1 and Example 2 showed the ultraviolet transmittance required for ultraviolet sterilization.
Example 1 84.55
Example 2 83.42
Comparative Example 1 0.47
3) Heat sealability The heat seal curves of Examples and Comparative Examples are as shown in FIG. 5, and both Example 1 and Example 2 were capable of heat sealing at low temperatures.
[0023]
【The invention's effect】
In a deoxygenated packaging body in which the individually packaged contents and oxygen scavenger are stored in an outer bag having gas barrier properties and hermetically sealed for the outer bag, the interior film used for individual packaging is an unstretched polypropylene film and a metallocene LL With the laminate film, it is possible to prevent oxidation of the contents, generation of mold, etc., and prevent drying or moisture absorption of the contents after opening the exterior bag. By selecting the anchor coating agent, it was possible to provide an interior film for deoxygenated packaging that did not deteriorate the UV sterilization effect after individual packaging and had good suitability for packaging machinery during individual packaging.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a film showing an example of an interior film for deoxygenating packaging of the present invention.
FIG. 2 is a cross-sectional view illustrating the concept of deoxidation packaging.
FIG. 3 is a film cross-sectional view showing an example of a film forming an outer bag for deoxygenation packaging.
FIG. 4 is a cross-sectional view showing an example of a deoxygenated packaging interior film according to the prior art.
5 is a heat seal curve of Example 1, Example 2, and Comparative Example 1. FIG.
[Explanation of symbols]
K Contents 1 Deoxygenated package 2 Interior bag 2S Interior bag space 3 Exterior bag 3S Exterior bag space 4 Oxygen absorber 5 Sealing part 6 (inside bag) Sealing part 20 Film laminate for interior 21 Base material layer 22 Heat seal layer AC Anchor coating agent 30 Exterior film laminate 31 Base material layer 32 Heat seal layer 33 Intermediate layer h Fine hole

Claims (3)

A packaging bag that contains an individual packaging bag containing contents and an oxygen scavenger in an outer bag having gas barrier properties, and is hermetically packaged. The film of the individual packaging bag has a thickness of 15 to 50 μm from the outside . Deoxygenation packaging comprising a laminate film composed of an unstretched polypropylene film and a linear low-density polyethylene resin layer having a thickness of 15 to 50 μm and a density of 0.89 to 0.917 Interior film. The laminating film of the individual packaging bag is a laminating film in which a linear low density polyethylene resin is formed by extrusion laminating on one side of an unstretched polypropylene film coated with an anchor coating agent composed mainly of a polyolefin resin. The interior film for deoxygenation packaging according to claim 1, wherein The interior film for deoxygenated packaging according to claim 1 or 2, wherein the laminate film of the individual packaging bag has an ultraviolet transmittance of 70% or more at a wavelength of 250 nm.

Images