JP2000142815A - Deoxidizing airtight packaging container and storing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deoxidizing airtight packaging container which is superior in deoxidizing characteristics, with which contents can be confirmed without opening the packaging container and which maintains gas barrier characteristics of the packaging container without using a heating process, and storing method of food or medicine using the same. SOLUTION: This packaging container is made by superposing, so that sealant layers face each other, and by heat sealing a deoxidizing multi-layer body having at least three layers of a gas barrier layer, an oxygen absorption layer and a sealant layer, and a transparent gas barrier multi-layer body having at least two layers of a gas barrier resin layer comprising nylon MXD6 and a sealant layer. In this case, food or medicine is stored using, for a heat sterilization process, a deoxidizing airtight container, and the oxidation transparency coefficient under 23 deg.C, 60%RH of whose deoxidizing multi-layer body and the transparent gas barrier multi-layer body has gas barrier characteristics of 20 cc/cm2.atm.day or less whether the same is heat processed or not. By this, the high temperature/high moisture heat process of the deoxidizing packaging container becomes possible, and food or medicine requiring heat process sterilization can be stored for a long time in an anoxia condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preserving articles using a sealed packaging container having deoxidizing properties and transparent contents, and a container suitable for the method. In particular, the present invention relates to a method for preserving foods or medicines for a long time after heat treatment, and a container suitable for the method.

[0002]

2. Description of the Related Art In recent years, as one of the oxygen-absorbing packaging techniques, a package is made of a multilayer material in which an oxygen-absorbing resin composition containing an oxygen-absorbing composition is arranged to improve the gas barrier properties of a container. At the same time, a package having a package container provided with a deoxidizing function is being developed. A package having a deoxidizing function usually includes an oxygen-absorbing resin layer containing an oxygen-absorbing composition as an intermediate layer, and a gas barrier layer having gas barrier properties and an oxygen-permeable layer having oxygen permeability on both sides thereof. It is composed of a deoxygenated multilayer body provided. The deoxidizing multilayer body has been developed as a sheet-like or film-like multilayer resin laminated structure that can be easily formed into a packaging container such as a bag, a cup, or a tray.

[0003] Deoxygenated multilayers are generally used as packaging containers for long-term storage of foods and pharmaceuticals. As a form in which the contents can be seen from the outside of the package, an outer wrapping bag having transparency and preservability of the contents, which is composed of a combination of a deoxidizing multilayer film and a transparent film having a gas barrier property, is disclosed in Japanese Unexamined Utility Model Publication No. 6-83340. No., published in Japanese Unexamined Patent Publication No. However, ethylene vinyl alcohol copolymers and the like described in the publication as a gas barrier layer of a transparent film having gas barrier properties are filled with foods and pharmaceuticals that require heat sterilization, and then boiled, retorted, and high retorted. When heat sterilization treatment under high temperature and high humidity is performed, the gas barrier property of the gas barrier layer is reduced, the oxygen concentration in the bag cannot be kept low, and long-term storage of foods and pharmaceuticals may be difficult. .

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to be able to check the contents without opening the packaging container, to keep the oxygen concentration in the container low even after the heat treatment,
It is an object of the present invention to provide an oxygen-absorbing hermetically sealed packaging container excellent in oxygen-absorbing property that enables long-term storage of an article, and a method for storing an article using the container. Another object of the present invention is to provide a method for preserving food or a medicine for a long period of time after performing a heat treatment, and a hermetically sealed packaging container excellent in deoxidation suitable for the method.

[0005]

Means for Solving the Problems The present invention provides at least:
A deoxidizing multilayer body including three layers of a gas barrier layer, an oxygen absorbing layer, and a sealant layer, and at least nylon MXD6
And a transparent gas barrier multilayer body having two layers of a gas barrier resin layer and a sealant layer, each of which is laminated and heat-sealed so that the sealant layers face each other. , 6
Oxygen permeability coefficient at 0% RH is 20 cc / m ² · atm · day or less, preferably 10 cc / m ² · atm · day or less irrespective of heat treatment. The present invention relates to a method for preserving an article by performing a heat sterilization treatment using a container.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. [Deoxidized multilayer body] The deoxidized multilayer body used in the packaging container of the present invention includes at least a gas barrier layer made of a gas barrier material, and an oxygen-absorbing resin composition in which a deoxidizer is mixed with a thermoplastic resin. It is a deoxygenated multilayer body composed of three layers, an oxygen absorption layer and a sealant layer made of a thermoplastic resin having oxygen permeability and heat sealing properties.

The gas barrier layer has an oxygen permeability coefficient at 23 ° C. and 60% RH of 20 ° C. regardless of the presence or absence of heat treatment.
cc / m ² · atm · day or less, preferably 10 c
It is a layer of c / m ² · atm · day or less. A preferred gas barrier layer has an oxygen permeability coefficient of 2 even after heat treatment.
A gas barrier layer made of metal foil such as aluminum foil or nylon MXD6 resin, which does not exceed 0 cc / m ² · atm · day. The gas barrier layer preferably has a thickness of 5 to 100 μm. The nylon MXD6 resin is a resin mainly composed of nylon MXD6 which is a polyamide composed of metaxylylenediamine and adipic acid. As long as the gas barrier property is not impaired, it may be stretched, mixed with another resin, or composited with another resin by lamination or the like.

As the oxygen absorber used in the oxygen absorbing layer, an oxygen absorber composition containing iron powder as a main component and a metal halide as an oxygen absorption accelerator is preferably used. As iron powder, for example, spray iron powder, sea surface iron powder, electrolytic iron powder, iron grinding powder,
Pulverized iron or the like is used, and iron powder having a low content of oxygen and silicon as impurities and a metal iron content of 95% by weight or more is particularly preferably used. The metal halide is preferably an alkali metal or alkaline earth metal chloride, bromide or iodide. In the present invention, an iron powder composition coated with an alkyl metal halide or an alkyl earth metal halide is preferably used, which is prepared by mixing an aqueous metal halide solution with iron powder and then drying it to remove water. .

The thermoplastic resin used for the oxygen absorbing layer is
Polyethylenes such as polyethylene, polypropylene and polymethylpentene; polystyrenes such as polystyrene and modified products thereof; various ethylene copolymers such as EVA, EMMA and EAA; and thermoplastic resins such as elastomers. Polypropylene is preferred. These resins are used singly or in an appropriate blend. In addition, various additives such as alkaline earth metal oxide, activated carbon, zeolite, and titanium oxide can be added to the iron-based deoxidizing agent in the oxygen absorbing layer.

Examples of the thermoplastic resin used for the sealant layer include polyolefins such as polyethylene, polypropylene and polymethylpentene, polystyrenes such as polystyrene, and modified products thereof, EVA, EMMA, and EVA.
Examples thereof include thermoplastic resins such as various ethylene copolymers such as AA and elastomers, and polyethylene and polypropylene are preferable. It is preferable to use a resin similar to the resin used for the oxygen absorbing layer. .

[Transparent Gas Barrier Multilayer Body] The transparent gas barrier multilayer body used in the packaging container of the present invention comprises at least a gas barrier layer made of a gas barrier resin made of nylon MXD6 resin and a heat sealable thermoplastic resin. It is a transparent gas barrier multilayer body composed of two sealant layers, each layer being sequentially laminated and having transparency.

For the gas barrier layer of the transparent gas barrier multilayer body, nylon MXD6, preferably stretched nylon MXD6 is used. By using nylon MXD6, a multilayer body having no gas barrier property even when subjected to heat treatment and having excellent impact resistance and transparency can be obtained. The oxygen permeability coefficient of the transparent gas barrier multilayer body at 23 ° C. and 60% RH was 20 cc /
m ² · atm · day or less, preferably 10 cc / m ²
-Atm-day or less. The thickness of the gas barrier layer is 5
It is preferably from 100 to 100 μm. You may mix with another resin as long as gas barrier property and transparency are not impaired. In the case of mixing with another resin, it is preferable to mix a transparent thermoplastic resin in an amount not exceeding 50% by weight, since gas barrier properties and impact resistance are high. Further, if necessary, it may be stretched or composited with another resin by lamination.

[0013] The sealant layer of the transparent gas-barrier multilayer body includes polyolefins such as polyethylene, polypropylene and polymethylpentene, polystyrenes such as polystyrene and their modified products, EVA, EMMA, EAA.
Various thermoplastic resins such as copolymers of ethylene and elastomers are preferably used.

In the present invention, layers other than the gas barrier layer, the oxygen absorbing layer and the sealant layer can be added to the oxygen-absorbing multilayer body constituting the oxygen-absorbing packaging container, as long as their functions are not impaired. Also, layers other than the gas barrier resin layer and the sealant layer can be added to the transparent gas barrier multilayer body constituting the oxygen-absorbing packaging container of the present invention as long as their functions are not impaired. The deoxidizing multilayer body and the transparent gas barrier multilayer body are manufactured by laminating in any order so that the respective layers are arranged as described above.

[Oxygen-removable sealed packaging container] The oxygen-removable sealed packaging container of the present invention is obtained by laminating the above-described oxygen-removable multilayer body and the transparent gas-barrier multilayer body such that the sealant layers face each other. It is a hermetically sealed packaging container.
The form of the oxygen-absorbing sealed packaging container of the present invention is obtained by thermoforming a packaging bag comprising a combination of a film comprising the oxygen-absorbing multilayer and a film comprising the transparent gas-barrier multilayer, and a sheet comprising the oxygen-absorbing multilayer. Container consisting of a combination of a tray consisting of a transparent gas barrier multilayer body and a top film consisting of a transparent gas barrier multilayer body, from a combination of a tray formed by thermoforming a sheet consisting of a transparent gas barrier multilayer body and a top film consisting of a deoxidizing multilayer body. Is exemplified.

The deoxygenated hermetically sealed packaging container of the present invention is made of a transparent film as a member, so that the contents can be checked without opening the packaging container, and the packaging container becomes easy to handle. By using the oxygen-absorbing multilayer body as a member, not only oxygen inside the packaging container but also slightly invading oxygen from outside the packaging container can be absorbed, and the inside of the packaging container can be maintained in an oxygen-free state. Can be stored for a long time.

After filling the food or medicine into the deoxidized hermetically sealed packaging container of the present invention, preferably by heating,
The contents can be confirmed and, at the same time, long-term storage is possible. In particular, the oxygen-absorbing hermetically sealed packaging container of the present invention can keep the oxygen concentration in the container low even if it is heat-treated after filling the food or medicine. Heat treatment condition is 80 ° C
The temperature is preferably not less than 4 minutes and not more than 90 minutes at a temperature of not less than 150 ° C and more preferably not less than 10 minutes and not more than 40 minutes at a temperature of not less than 85 ° C and not more than 135 ° C. The oxygen-absorbing hermetically sealed packaging container of the present invention retains the gas barrier properties of the gas barrier layer even after such a heat treatment, and does not lower the oxygen-absorbing performance.

[0018]

EXAMPLES The present invention will be described in more detail with reference to examples. Note that the present invention is not necessarily limited to the embodiments. Example 1 Polyethylene terephthalate (PET) and nylon MXD6 were blended at a weight ratio of 1: 1 and stretched. A gas barrier layer composed of a gas barrier film having a thickness of 25 μm and a sealant composed of a low density polyethylene film having a thickness of 60 μm. Gas barrier layer / oxygen absorber composition (34% thick gas barrier laminated film composed of PET / nylon 6 / aluminum foil) (a 2% calcium chloride coated iron powder, average Oxygen absorbing layer of 30 μm thick composed of a low-density polyethylene film containing 30% by weight of (30 μm in particle size) / thickness of 40 of linear low-density polyethylene film
A sealed packaging bag (8 cm × 15) formed by superposing heat-sealing a deoxidizing multilayer body in which each layer of a μm sealant layer is sequentially laminated so that the sealant layers face each other.
10 cm) and sealed with 55 g of dog food (air volume: 60 cc), and stored at 23 ° C. and 60% RH.

After 3 days, the oxygen permeability coefficient of the transparent gas barrier multilayer was measured at 23 ° C. and 60% RH.
c / m ² · atm · day. The oxygen permeability coefficient of the deoxidizing multilayer having the aluminum foil in the gas barrier layer was so small as to be negligible. One month later, when the oxygen concentration in the bag was measured, it was 0.07%. When the bag was opened at the same time and observed, the dog food was not discolored and was well stored.

Example 2 Nylon 6 / Nylon MXD
6 / Nylon 6 gas-barrier laminated film with a thickness of 25 μm formed by stretching three layers (manufactured by Mitsubishi Chemical Corporation, trade name:
(Nylon Super Neil), a transparent gas barrier multilayer consisting of two layers of a 50 μm thick sealant layer consisting of a gas barrier layer consisting of a linear low density polyethylene film and a gas barrier laminate film of PET / nylon 6 / aluminum foil. 34 μm thick gas barrier layer / oxygen absorber composition (calcium chloride 2% coated iron powder, average particle size 30
deoxygenating multilayer body in which each layer of a 30 μm-thick oxygen absorbing layer made of a low-density polyethylene film containing 40% by weight of a 40 μm) / 40 μm-thick sealant layer made of a linear low-density polyethylene film is sequentially laminated. And a heat-sealed sealed packaging bag (7 cm × 13 cm) filled with 70 g of Kinpira burdock (air volume 60 c).
c) Ten pieces were prepared, boiled at 90 ° C. for 30 minutes, and stored at 23 ° C. under 60% RH.

After 3 days, the oxygen permeability coefficient of the transparent gas barrier multilayer was measured at 23 ° C. and 60% RH.
c / m ² · atm · day. Another month later,
When the oxygen concentration in the bag was measured, it was 0.05%. At the same time, when the bag was opened and observed, there was no discoloration in the burdock and the taste was well maintained.

Example 3 Nylon 6 / Nylon MXD
6 / Nylon 6 gas-barrier laminated film with a thickness of 25 μm formed by stretching three layers (manufactured by Mitsubishi Chemical Corporation, trade name:
Nylon Super Neil) gas barrier layer consisting of two layers of a sealant layer having a thickness of 50 μm consisting of a gas barrier layer consisting of a propylene-ethylene block copolymer film and a gas barrier laminate film of PET / nylon 6 / aluminum foil. A gas barrier layer having a thickness of 34 μm / a propylene-ethylene block copolymer film containing 35% by weight of an oxygen scavenger composition (calcium chloride coated iron powder, average particle diameter 30 μm) 30 μm thick
The oxygen-absorbing layer / the oxygen-absorbing multilayer body obtained by sequentially laminating each layer of a sealant layer having a thickness of 40 μm comprising a propylene-ethylene block copolymer film is overlapped and heat-sealed so that the sealant layers face each other. A sealed packaging bag (14 cm × 15 cm) was filled with 160 g of spaghetti raw type long life noodles to make 10 sealed packages (air volume 30 cc), boiled at 100 ° C. for 30 minutes, and 23 ° C. 60% RH Saved below.

After 3 days, the oxygen permeability coefficient of the transparent gas barrier multilayer was measured at 23 ° C. and 60% RH.
/ M ² · atm · day. One month later, when the oxygen concentration in the bag was measured, it was 0.08%. When the bag was opened at the same time and observed, the raw noodles had no discoloration and the taste was well maintained.

Example 4 Nylon MXD6 and Nylon 6 were mixed at a weight ratio of 1: 1 and stretched to obtain a 15 μm-thick gas barrier film (trade name: Uniathlon TB-1000, manufactured by Idemitsu Petrochemical Co., Ltd.). Gas barrier layer / a propylene-ethylene block copolymer film and a 50 μm-thick sealant layer consisting of two transparent gas-barrier multilayers, and a PET / nylon 6 / aluminum foil gas-barrier laminated film having a thickness of 34 μm. Gas barrier layer / oxygen absorber composition (calcium chloride 2% coated iron powder,
Propylene containing 45% by weight of an average particle size of 30 μm).
Thickness 30μ consisting of ethylene block copolymer film
The oxygen-absorbing layer having a thickness of 40 m and the oxygen-absorbing multilayer body formed by sequentially laminating each layer of a sealant layer having a thickness of 40 µm comprising a propylene-ethylene block copolymer film are overlapped so that the sealant layers face each other, and heat-sealed. The sealed packaging bag (14 cm × 15 cm) was filled with 160 g of black beans containing the liquid, and 10 sealed packages (5 cc of air volume) were prepared, and retorted at 120 ° C. for 30 minutes.
Stored at 60 ° C and 60% RH.

After 3 days, the oxygen permeability coefficient of the transparent gas barrier multilayer was measured at 23 ° C. and 60% RH.
/ M ² · atm · day. One month later, when the oxygen concentration in the bag was measured, it was 0.08%. When the bag was opened at the same time and observed, the black beans had no discoloration and the taste was well maintained.

Example 5 A 370 μm-thick protective layer composed of a propylene-ethylene block copolymer sheet / amorphous polyamide composed of a copolymer of hexamethylenediamine, terephthalic acid and isophthalic acid, and nylon M
A 50 μm thick gas barrier layer / oxygen absorber composition (50% by weight of calcium chloride coated iron powder, average particle size of 50 μm) composed of a 50:50 mixed resin film with XD6 resin was used.
Deoxygenation in sheet form in which each layer of a 200 μm-thick oxygen-absorbing layer composed of a propylene-ethylene block copolymer film and a 120 μm-thick sealant layer composed of a propylene-ethylene block copolymer film is sequentially laminated. Rice porridge 3 in a tray-shaped container (internal volume 350 cc, squeezing ratio 1.5) obtained by thermoforming the porous multilayer body
Gas barrier laminate film having a thickness of 25 μm and three layers of nylon 6 / nylon MXD6 / nylon 6 stretched as a top film (Mitsubishi Chemical Corporation)
Product name: Nylon Super Neal)
A packaging in which a transparent gas barrier multilayer body composed of two layers of a 50 μm thick sealant layer composed of a 5 μm gas barrier layer / a propylene-ethylene block copolymer film is overlapped so that the sealant layers face each other, and sealed by heat sealing. Body (headspace air volume in container 50cc)
Ten pieces were prepared, subjected to a high retort treatment at 135 ° C. for 10 minutes, and stored at 23 ° C. under 60% RH.

After 3 days, the oxygen permeability coefficient of the transparent gas barrier multilayer was measured at 23 ° C. and 60% RH.
/ M ² · atm · day. One month later, when the oxygen concentration in the bag was measured, it was 0.03%. At the same time, when the bag was opened and observed, the rice porridge had no discoloration and the taste was well maintained.

Example 6 Protective layer of 370 μm thick made of propylene-ethylene block copolymer sheet / 50 μm thick gas barrier layer of nylon MXD6 /
A tray-shaped container (internal volume: 350 cc, drawing ratio) obtained by thermoforming a sheet-shaped deoxidizing multilayer body in which each layer of a 370 μm-thick sealant layer composed of a propylene-ethylene block copolymer sheet is sequentially laminated. 1.5) is filled with 300 g of rice porridge, and a gas barrier layer / oxygen absorber composition having a thickness of 34 μm made of a gas barrier laminate film made of PET / nylon 6 / aluminum foil as a top film (iron powder coated with 2% calcium chloride) , An average particle size of 30 μm) and a 30 μm-thick oxygen-absorbing layer composed of a propylene-ethylene block copolymer film containing 30% by weight / a 40 μm-thick sealant layer composed of a propylene-ethylene block copolymer film. The laminated oxygen-absorbing multilayer body is overlapped so that the sealant layers face each other and heat-sealed. To make 10 sealed packages (headspace air volume in container 50 cc)
Perform high retort treatment at 5 ° C for 10 minutes, and 23 ° C, 60% R
Stored under H.

Three days later, the oxygen permeability coefficient of the transparent gas-barrier multilayer body was measured at 23 ° C. and 60% RH.
c / m ² · atm · day. Another month later,
When the oxygen concentration in the bag was measured, it was 0.03%. At the same time, the bag was opened and observed.
The taste was also well maintained.

Comparative Example 1 As a transparent gas barrier multilayer, an ethylene vinyl alcohol copolymer film (manufactured by
Example 1 except that a laminated film composed of two layers of a gas barrier layer of 15 μm in thickness and a sealant layer of 50 μm in thickness of a propylene-ethylene block copolymer film made of Kuraray, trade name EF-XL) was used. In the same manner as described above, 10 sealed packages were prepared, boiled at 90 ° C. for 30 minutes, and stored at 23 ° C. and 60% RH. 3
After a day, the oxygen permeability coefficient of the transparent gas barrier multilayer body is set to 23 ° C.
When measured under 60% RH, 26 cc / m ² · at
m.day, and when the packaging bag was opened on the seventh day, discoloration of the kinpira burdock was confirmed. One month later, the oxygen concentration in the bag was 8.5%, and the odor was decayed from the pumpkin burdock.

COMPARATIVE EXAMPLE 2 A 370 μm-thick protective layer made of a propylene-ethylene block copolymer sheet / ethylene-vinyl alcohol copolymer film (trade name: EP-, manufactured by Kuraray Co., Ltd.) was used as a tray-shaped molded container. T10
A gas barrier layer having a thickness of 50 μm comprising 1) / thickness 37 comprising a propylene-ethylene block copolymer film
A sealed package 10 was prepared in the same manner as in Example 6 except that a tray-shaped molded container obtained by thermoforming a sheet-shaped deoxidized multilayer body in which each layer of a 0 μm sealant layer was sequentially laminated was used. Individual pieces were prepared, subjected to a high retort treatment at 135 ° C. for 10 minutes, and stored at 23 ° C. and 60% RH. Three days later,
The oxygen permeability coefficient of the transparent gas barrier multilayer body is 23 ° C and 60%
When measured under RH, 150 cc / m ² · atm ·
It was day. One month later, when the oxygen concentration in the bag was measured, it was 10.0%. When the bag was opened at the same time and observed, discoloration was observed in the rice porridge.

[0032]

The deoxidized hermetically sealed packaging container of the present invention allows the contents to be visually recognized without opening the packaging container, so that the product can be easily handled and, in addition to the oxygen inside the packaging container, the packaging can be performed. It can also absorb oxygen that slightly enters from outside the container, keep the inside of the packaging container in an oxygen-free state, and allow long-term storage of articles. Furthermore, the packaging container of the present invention does not lower the gas barrier properties of the packaging container even after subjected to heat treatment under high temperature and high humidity such as boil treatment, retort treatment, high retort treatment, and efficiently removes oxygen in the packaging container. Since it absorbs and maintains the inside of the packaging container in an oxygen-free state, foods and pharmaceuticals that require heat sterilization can be stored for a long period of time.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) B32B 27/18 B32B 27/18 G F term (reference) 3E067 AA11 AB01 AB81 BA12A CA04 CA06 CA11 CA24 CA30 EE48 FA01 GB13 GD07 4B021 LA05 LA07 LA15 LA17 LA24 LA25 LP01 LP07 MC04 MK10 MK14 4F100 AA05H AB10 AB33 AK06 AK41 AK46D AK48 AK63 AK64 AL05 AS00C AS00E BA02 BA03 BA07 BA10A BA10C CA09 GB16 JD02A JD02D JD14B JK12 JL12C L

Claims (4)

[Claims] An oxygen-absorbing multilayer body having at least three layers of a gas barrier layer, an oxygen absorbing layer and a sealant layer, and a transparent gas barrier multilayer body having at least two layers of a gas barrier layer made of nylon MXD6 resin and a sealant layer. And a heat-sealed container with the sealant layers facing each other, wherein the oxygen-desorbing multilayer body and the transparent gas-barrier multilayer body have an oxygen permeability coefficient at 23 ° C. and 60% RH. 2 with or without heat treatment
A deoxidized hermetically sealed packaging container having a gas barrier property of 0 cc / m ² · atm · day or less. 2. A hermetically sealed package comprising an article stored in the deoxidized hermetically sealed packaging container according to claim 1. 3. A hermetically sealed package obtained by storing an article in the deoxidized hermetically sealed packaging container according to claim 1 and performing a heat treatment at a temperature of from 80 ° C. to 150 ° C. for from 4 minutes to 90 minutes. 4. An article is stored in the deoxygenated hermetically sealed packaging container according to claim 1, heated at a temperature of 80 ° C. to 150 ° C. for 4 minutes to 90 minutes, and then stored. The method of storing articles.