JP2002052655A - Oxygen absorbable multilayered material and method for preserving article containing low moisture content using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxygen absorbable multilayered material having good oxygen absorbability under low moisture environment and a method for preserving an article containing low moisture content to be preserved using the same without bringing about the lowering of quality thereof or a change in the properties thereof. SOLUTION: The oxygen absorbable multilayered material consists of a heat seal layer (1), an oxygen absorbent (X), an oxygen absorbing layer (21) or an intermediate layer (22) and a gas barrier layer (3) and the oxygen absorbent (X) embedded so as to be unevenly distributed to the oxygen absorbing layer 21 or to the bonding surface of the heat seal layer (1) and the intermediate layer (22) contains metal bromide or iodide as an oxygen absorption accelerating agent. This oxygen absorbable multilayered material is used as a part of a packing container to preserve the article with low moisture content. The article to be preserved with low moisture content like powder food can be preserved in a good state under low oxygen environment without bringing about the lowering of quality or a change in properties.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxygen-absorbing multilayer body excellent in storing low-moisture-content articles, and a method for storing contents using the multilayer body.

[0002]

2. Description of the Related Art In recent years, as one of deoxygenation packaging techniques, a container is composed of a multilayer material having an oxygen absorbing layer made of an oxygen absorbing resin composition obtained by mixing an oxygen absorbing agent with a thermoplastic resin. A packaging container has been developed in which the gas barrier property is improved and the container itself is provided with a deoxidizing function.
A packaging container having a deoxygenating function is usually an oxygen-absorbing multilayer having an oxygen-absorbing layer containing an oxygen-absorbing composition as an intermediate layer, an outer layer having gas barrier properties on the outside, and an inner layer having oxygen permeability on the inside. It is composed of a body and has been developed as a multi-layer packaging container that is easy to mold and process as containers such as bags, cups, trays, and bottles.

[0003] Examples of the oxygen-absorbing multilayer body include an oxygen-absorbing multilayer body in which an iron-based oxygen absorbing composition is dispersed in a resin as disclosed in JP-A-2-72851 and JP-A-4-90848. Absorbing films are available. Also,
JP-A-8-72941 proposes a technique for improving the oxygen absorbing performance of an oxygen-absorbing multilayer body. Furthermore, JP-A-8-132573 and JP-A-9-40024 disclose an oxygen-absorbing multilayer body and a multilayer film having a configuration in which a polyolefin layer is interposed between an oxygen-absorbing agent-containing resin layer and a gas barrier layer.

Japanese Patent Application Laid-Open No. 11-320767 discloses a method in which a granular oxygen absorbent is sprayed between a first thermoplastic resin film and a second thermoplastic resin film of a multilayer body, sandwiched and pressed. An integrated oxygen absorbing multilayer body and a method of making the same are disclosed. However, although iodide and bromide are listed as one of the promoters of the oxygen absorption reaction, iodide and bromide are not considered at all because they are inferior to chlorides such as calcium chloride and sodium chloride. When used for low moisture content articles, it has been difficult to absorb and store oxygen.

On the other hand, oxygen absorbers are disclosed in
No. 33980 discloses an oxygen absorbent in which metal powder is coated with a metal halide. Oxygen absorbers of this type are used for the preservation of high (multi) water-containing foods that can utilize the water evaporating from the material to be preserved, since the deoxidation reaction by reducing metals requires the presence of water. I have.

As for the preservation of dried foods and the like having a low water content, a self-reactive oxygen scavenger is known in which a water donor is present in an oxygen absorber to supplement the water required for oxygen absorption. Furthermore, Japanese Patent Application Laid-Open No. 9-268235 discloses an oxygen-absorbing composition in which a reducing metal and at least one of an iodide and a bromide as a promoter are kneaded with a thermoplastic resin. However, if a self-reactive oxygen absorber that retains water is used for preservation of preservation materials with low water content, the transfer of water in the water retention component to the preservation materials cannot be avoided. This causes problems such as deterioration of flavor of preserved material, change in properties, chemical change, and propagation of microorganisms. In addition, even in the case of an oxygen-absorbing composition using an iodide or bromide as an accelerator, the accelerator must be kneaded with a resin at a high temperature, so that the accelerator deteriorates and its effect cannot be sufficiently obtained. Had a problem with the storage stability.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an oxygen-absorbing multilayer body which eliminates deterioration of an oxygen absorbent and absorbs oxygen even under low moisture, and a low moisture-containing article using this multilayer body. Another object of the present invention is to provide a storage method.

[0008]

Means for Solving the Problems The present inventor has developed a multilayer structure comprising a heat seal layer (1), an oxygen absorbent (X), an oxygen absorbent layer (21) or an intermediate layer (22), and a gas barrier layer (3). Body, ubiquitous in the oxygen absorbing layer (21) or a heat sealing layer
The oxygen absorbent (X) which is unevenly embedded in the bonding surface between (1) and the intermediate layer (22) partially includes an oxygen-absorbing multilayer body containing metal bromide or metal iodide as an oxygen absorption accelerator. By using the packaging container used, the contents with low moisture content were successfully preserved.

That is, the present invention provides a heat-sealing layer (1) made of a thermoplastic resin, and an oxygen-absorbing layer (2) made of an oxygen-absorbing resin composition containing a thermoplastic resin and an oxygen absorbent.
1) An oxygen-absorbing multilayer body in which at least three layers of a gas barrier layer (3) made of a gas-barrier material are sequentially laminated, wherein the thermoplastic resin of the heat-sealing layer (1) and the heat of the oxygen-absorbing layer (21) The plastic resin is a polyolefin having a density of 0.940 or less, and the oxygen absorbent in the oxygen absorbing layer is an oxygen absorbing composition containing a reducing metal as a main component and at least one of bromine or iodine alone and a metal salt as an accelerator. The present invention relates to an oxygen-absorbing multilayer body characterized by the following.

The present invention also relates to a heat seal layer (1) comprising a thermoplastic resin, an oxygen absorbent (X),
Intermediate layer made of thermoplastic resin joined adjacent to (1)
(22) and gas barrier layer made of gas barrier material (3)
Wherein the oxygen absorbent (X) comprises at least three layers.
An oxygen-absorbing multilayer body unevenly distributed on the joint surface between (1) and the layer (22), wherein the oxygen absorbent (X) is mainly composed of a reducing metal and a metal bromide salt or a metal iodide salt is used as an accelerator. An oxygen-absorbing composition comprising: an oxygen-absorbing composition comprising:

The present invention is also a method for disposing the heat-sealable layer (1) of the above-mentioned oxygen-absorbing multilayer body inside a packaging container, and for preserving a low moisture content article by using a part of the packaging container.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
Heat sealing layer (1), oxygen absorbing layer (21) and intermediate layer (2
The thermoplastic resin constituting 2) is preferably a thermoplastic resin excellent in welding property and oxygen permeability, and has a density of 0.9.
It is a polyolefin of 40 or less. Specifically, polyethylenes exemplified by low-density polyethylene and linear low-density polyethylene, polypropylenes exemplified by propylene-ethylene block copolymer and propylene-ethylene random copolymer, metallocene-catalyzed polyethylenes and polypropylene One-site catalysts such as polyolefins, polymethylpentene, ethylene-vinyl acetate copolymers and elastomers exemplified by ethylene-α-olefin copolymers or mixtures thereof. Among them, low density polyethylenes such as low density polyethylene, linear low density polyethylene and metallocene catalyzed polyethylene are particularly preferred.

The heat sealing layer (1) or the oxygen absorbing layer (2)
1) The intermediate layer (22) is preferably colored with a pigment in order to hide the oxygen absorbent. Examples of the pigment include iron oxide such as red iron oxide, carbon black, calcium carbonate, a cadmium pigment, and titanium oxide. Of these, titanium oxide is preferably used. The amount of the pigment depends on the thickness of the film, but in the thermoplastic resin,
0.5 to 40% by weight is preferred. If the amount of the inorganic substance such as a pigment is too small, the concealment of the oxygen absorbent is insufficient, and if the amount is too large, the weldability decreases. The use of pigmented thermoplastic resin makes the oxygen absorber less visible from the outside, and iron powder and iron rust when using an iron powder-based oxygen absorber are concealed, resulting in excellent oxygen absorption of appearance. It becomes a multilayer body. Also,
The resin constituting the heat-sealing layer (1) or the oxygen-absorbing layer (2) may optionally contain additives other than pigments, for example, a slip agent, an antioxidant, an alkaline earth metal oxide, activated carbon,
Zeolites and the like can be added.

A heat sealing layer (1), an oxygen absorbing layer (21),
As the resin used for forming the intermediate layer (22), it is preferable to select a combination of resins having compatibility with each other, that is, a combination of resins capable of welding layers to be joined to each other. The resin used for the heat sealing layer (1) and the oxygen absorbing layer (21) or the intermediate layer (22) may be a combination of different resins, but a combination of the same type of resin is preferable.
In addition, the heat seal layer (1) has improved heat sealability,
A thermoplastic resin film having two or more layers can be used to improve the concealing property and the film strength.

The oxygen absorbent (X) is an oxygen absorbing composition comprising a reducing metal and an oxygen absorption promoter. Among these, a known metal as an oxygen absorbing component can be used as the reducing metal. Specifically, it is a metal powder such as a granular iron powder, a copper powder and a zinc powder, and is preferably an iron powder. These are used alone or in combination. As the iron powder, for example, sprayed iron powder, sea surface iron powder, electrolytic iron powder, iron ground powder, crushed iron, etc. are used. However, the content of oxygen and silicon as impurities is small, and iron having a metal iron content of 95 wt% or more is used. Powders are particularly preferably used. Further, in order to improve the contact between the reducing metal and oxygen and to reduce the thickness of the oxygen-absorbing multilayer body, the average particle size of the reducing metal is preferably from 1 to 150 μm, more preferably from 5 to 100 μm.

The oxygen absorption accelerator acts catalytically on the oxygen absorption reaction of the reducing metal. As the oxygen absorption promoter of the present invention, iodine or bromine alone, metal iodide, or metal bromide is preferable. Specifically, an electrolytic iodide or bromide of an alkali metal or an alkaline earth metal is used. Alternatively, an electrolytic iodide or bromide of a transition metal such as copper, zinc, aluminum, tin, iron, cobalt, and nickel is used. Further, combinations of these can also be used. Among them, sodium bromide, potassium bromide, sodium iodide, potassium iodide and a combination thereof are preferred, and sodium bromide, potassium bromide, sodium iodide or a combination of potassium iodide and iodine is particularly preferred.

The oxygen absorption promoter may be mixed with the reducing metal powder. Preferably, the oxygen absorption promoter is coated on the reducing metal powder by, for example, contacting an aqueous solution of the oxygen absorption promoter with the reducing metal powder and drying. Is done. The content of the oxygen absorption accelerator contained in the oxygen absorber may be in a known range, for example, the amount of the reaction accelerating component is based on 100 parts by weight of the reducing metal.
Preferably 0.1 to 100 parts by weight, more preferably 0.1.
-5 parts by weight. In particular, when the oxygen absorption enhancer is attached to the iron powder, the amount thereof can be reduced.

Further, the oxygen absorbent composition used in the present invention may contain, if necessary, additives such as coloring pigments such as titanium oxide, fatty acid salts, dispersants such as silane and titanate, and antioxidants. , Alumina, clay, mica, silica,
Fillers such as calcium sulfate and calcium carbonate, activated carbon,
Adsorbents such as zeolites can be mixed or coated.

The oxygen absorbing layer (21) is a heat sealing layer (1)
It is formed by laminating an oxygen-absorbing thermoplastic resin composition obtained by blending an oxygen absorbent with a thermoplastic resin on the surface. In this case, the oxygen absorbent is substantially uniformly dispersed throughout the oxygen absorption layer (21). The multilayer body having such a distribution of the oxygen absorbent (X) is schematically shown in FIG. The oxygen absorbent is unevenly distributed on the joint surface with the heat seal layer (1).
The compounding amount of the oxygen absorbent in the oxygen-absorbing thermoplastic resin composition is 10 to 70% by weight, preferably 20 to 60% by weight. If the amount of the oxygen absorbent is too low, the oxygen absorption performance will not be sufficient. If the amount is too high, the amount of the resin component will decrease, and the workability and strength of the oxygen absorbing layer will be problematic.

Preferably, an oxygen absorbent is sprayed on the surface of the heat seal layer (1), and then a molten thermoplastic resin is laminated as an intermediate layer (22). In this case, the oxygen-absorbing multilayer body is a heat-sealing layer made of a thermoplastic resin.
(1) A multilayer body in which at least three layers of an intermediate layer (22) made of a thermoplastic resin and a gas barrier layer (3) made of a gas barrier material are sequentially laminated, wherein the heat seal layer (1) and the intermediate layer ( During the period 22), the granular oxygen absorbent (X) is unevenly distributed. Here, being unevenly distributed means that the granular oxygen absorbent (X) exists in at least one of the heat seal layer (1) and the intermediate layer (22), and is unevenly distributed between the layers. Means exist.

The method of spraying the oxygen absorbent is not limited as long as the oxygen absorbent is evenly and uniformly sprayed, and a known apparatus for spraying powder on a film can be preferably used. According to the spraying method, the process of kneading the oxygen-absorbing composition containing the iodide or bromide as the oxygen-absorbing promoter with the resin at a high temperature is prevented, so that the deterioration of the oxygen-absorbing promoter is prevented, and Excellent absorption performance.

The weight of the granular oxygen absorbent (X) sandwiched between the heat seal layer (1) and the intermediate layer (22) is preferably 1 per m ^{2 when} viewed from the direction perpendicular to the surface to which the oxygen absorbent is dispersed. １５０150 g, more preferably 3-100 g. If the amount of oxygen absorbent is too low, sufficient oxygen absorption performance cannot be obtained, and if it is too high, the mechanical strength and moldability of the multilayer body, the interlayer between the heat seal layer (1) and the intermediate layer (22) will not be obtained. A problem occurs in strength.

In this case, the oxygen absorbent (X) is blended in the heat seal layer (1) or the intermediate layer (22). Among them, it is unevenly distributed on the joint surface between the heat seal layer (1) and the intermediate layer (22). In other words, the granular oxygen absorbent (X) blended in the heat seal layer (1) or the intermediate layer (22) is distributed close to the joint surface between the heat seal layer (1) and the intermediate layer (22). Characterized by including a plurality of particles. A multilayer having such a distribution of the oxygen absorbent (X) is schematically shown in FIG.

As the gas barrier layer (3), a metal foil such as an aluminum foil, a resin film on which a metal or metal oxide such as aluminum, aluminum oxide and silicon oxide is deposited, a nylon such as MXD6, an ethylene-vinyl alcohol copolymer, A polyvinylidene chloride-coated film or the like is suitably used, and may be stretched as necessary or composited with another resin by lamination or the like as long as the gas barrier properties are not impaired.

The thermoplastic resin layer of the oxygen-absorbing multilayer body of the present invention
As a method for laminating (1), (2) and the gas barrier layer (3), known lamination methods and lamination methods such as co-extrusion, extrusion lamination, sandwich lamination and dry lamination are used.

For the purpose of protecting the gas barrier layer (3), a protective layer made of a thermoplastic resin can be laminated on the outside of the gas barrier layer, if necessary. As the resin used for the protective layer, for example, polyethylenes such as high-density polyethylene, propylene homopolymer, propylene-
Examples include polypropylenes such as ethylene random copolymer and propylene-ethylene block copolymer, polyamides such as nylon 6, nylon 6,6, polyesters such as polyethylene terephthalate, and combinations thereof.

The low moisture content article stored in the present invention refers to an article which has a low moisture content and a small amount of water to be diffused, so that the conventional self-reactive oxygen absorbent and oxygen absorbing multilayer body cannot be applied. The activity (sometimes referred to as Aw) is preferably 0.2 to 0.7, more preferably 0.2 to 0.5, or the water content is preferably 30% by weight or less, more preferably 1% or less. % To 10% by weight. In particular, as low-moisture-containing articles (packaged articles) to which the present invention can be applied, for example, as powders and granular foods, powdered soups, powdered beverages, powdered confections, seasonings, grain powders, nutritional foods, health foods, colorings , Flavors, spices and the like, and powders and granules include vitamins such as vitamin C and vitamin E, powders, powdered soap, toothpaste, industrial chemicals and the like. Furthermore, foods and chemicals which dislike the increase in water content, such as these molded articles (tablet type), and which need to avoid mixing of foreign substances can be exemplified.

The oxygen-absorbing multilayer body of the present invention is obtained by disposing the heat seal layer (1) inside a package and processing it into a package such as a bag or a tray used for a part of the package.
An oxygen-absorbing packaging container having excellent appearance, flavor retention, film properties, and oxygen-absorbing function can be obtained. Since the present packaging container exhibits an excellent effect of preventing quality deterioration due to oxygen, it is used for preserving various articles. In particular, since it has excellent oxygen absorption performance under low humidity, it is suitably applied to articles that have low water activity and need to be stored under dry conditions of low humidity. In order to store low moisture content articles that require low humidity storage conditions, the relative humidity (RH) of the atmosphere in which the low moisture content articles are stored is preferably 20 to 70%, more preferably 20 to 50%. Yes, it has sufficient preservability of packaged goods under these conditions. The packaging container comprising the oxygen-absorbing multilayer body of the present invention can perform deoxygenation under low humidity conditions without the presence of a moisture donor.

[0029]

EXAMPLES The present invention will be described in more detail with reference to examples. However, the present invention is not necessarily limited to the examples. Example 1 500 kg of reduced iron powder having an average particle size of 30 μm was put into a vacuum mixing dryer equipped with a heating jacket, and sprayed with 10 kg of an aqueous solution containing 25% by weight of potassium iodide and 25% by weight of iodine as an oxygen absorption promoter, 10 mmHg After drying at 120 ° C. under reduced pressure, the particles were sieved to remove coarse particles of 73 μm or more to obtain a granular oxygen absorbent 1 coated with an oxygen absorption promoter.

Next, using an extrusion laminator comprising a single screw extruder, a T-die, and a cooling roll, anchor coating was performed on the aluminum surface of the barrier layer (3) obtained by dry laminating 25 μm of the stretched polypropylene film and 9 μm of aluminum foil. Low-density polyethylene 50 μm as an intermediate layer (22)
Layer (3) / intermediate layer (2) obtained by extrusion lamination of
The multilayer film composed of 2) is unwound, and 30 g / m ^{2 of the} granular oxygen absorbent 1 is applied to the surface of the multilayer film on the side of the intermediate layer (22).
And 10% by weight of titanium oxide as a heat seal layer (1) so that the thickness becomes 30 μm from the extruder.
Compounded molten metallocene catalyst linear low-density polyethylene (manufactured by Dow Chemical Co., Ltd., trade name: affinity PT1450, melting point 99 ° C., density 0.902 g / cm ² )
Was extrusion-laminated and thermocompression bonded by applying a mirror-finished cooling roll from the heat seal layer (1) side to obtain an oxygen-absorbing multilayer film 1. The composition of the oxygen-absorbing multilayer film 1 is as follows: heat seal layer (1) (containing 10% by weight of titanium oxide); 30 μm / granular oxygen absorbent (X) sandwiched between both films (30 g / m ² ) / intermediate layer ( 22); 50
μm / aluminum foil; 9 μm / OPP film; 25 μm.

When the cross section of the oxygen-absorbing multilayer film was observed with a microscope, the heat-sealing layer (1) and the intermediate layer were observed.
And (22) are pressure-bonded and laminated without gaps, and the granular oxygen absorbent is bonded to the particles embedded in the heat seal layer (1) at the joint surface with the heat seal layer (1) intermediate layer (22) It was confirmed that there were particles embedded across both layers.

Next, a packaging bag (11 cm × 13 cm) was prepared from the oxygen-absorbing film 1 so that the heat seal layer (1) was placed inside the packaging bag. In this bag,
Three days after filling 50 g of a powder soup (water content 6% by weight, Aw 0.3) and 50 cc of air, the oxygen concentration in the bag was measured and found to be less than 0.1 vol%. When the package was stored at 23 ° C. for one month and opened, the flavor of the powder stock was good and no discoloration or solidification of the powder stock was observed.

Example 2 Using a single-screw extruder, an extrusion laminator comprising a T-die and a cooling roll, a heat-sealing layer
(1) Linear low-density polyethylene containing 5% by weight of titanium oxide (trade name: Novatec UC470, manufactured by Nippon Polychem Co., Ltd., melting point 126 ° C., density 0.924 g / c)
m ² ), a 50 μm-thick film is unwound, and a granular oxygen absorbent 1 is sprayed on the surface so as to have a thickness of 20 g / m ^2, and the thickness of the intermediate layer (22) is adjusted to 50 μm by an extruder. A low-density polyethylene in a molten state was extrusion-laminated and thermocompression-bonded by applying a cooling roll from the side of the intermediate layer (22) to obtain a multilayer film composed of the heat seal layer (1) / intermediate layer (22). A barrier layer (3) obtained by dry laminating a polyethylene terephthalate film (12 μm) and an aluminum foil (9 μm) was applied to the intermediate layer (2) of the multilayer film.
2) Dry lamination was performed on the side to obtain an oxygen-absorbing multilayer film 2. The composition of the oxygen-absorbing multilayer film 2 is as follows: heat seal layer (1) (containing 5% by weight of titanium oxide);
A granular oxygen absorber sandwiched between both films (20 g / m
² ) / Intermediate layer (22); 50 μm / aluminum foil; 9 μm / PET
Film: 12 μm.

When the cross section of the oxygen-absorbing multilayer film was observed with a microscope, the heat-sealing layer (1) and the intermediate layer were observed.
(22) are laminated by pressure bonding without gaps and integrated, and the particulate oxygen absorbent and both the particles embedded in the intermediate layer (22) and the heat sealing layer (1) at the joint surface and the intermediate layer (22) It was confirmed that there were particles embedded over the layers. This is shown schematically in FIG.

From the oxygen-absorbing film 2, a packaging bag (10) is formed such that the heat seal layer (1) is placed inside the packaging bag.
cm × 15 cm). In this bag, 50 g of powdered soup (water content: 3% by weight, Aw: 0.35) and 50 cc of air were sealed. After 3 days, the oxygen concentration in the bag was measured and found to be less than 0.1 vol%. In addition, this package
After storage at 3 ° C. for one month and opening, the flavor of the powdered soup was good.

Example 3 100 kg of reduced iron powder having an average particle size of 30 μm was put into a vacuum mixing dryer equipped with a heating jacket, and 5 kg of a 40% by weight aqueous solution of sodium bromide was sprayed.
After drying at 120 ° C. under a reduced pressure of 10 mmHg, the mixture was sieved to remove coarse particles having a size of 75 μm or more to obtain a granular oxygen absorbent 2 coated with sodium bromide as an oxygen absorption promoter.

Next, a 30 μm thick film made of low-density polyethylene was unwound as an intermediate layer (22) using an extrusion laminator consisting of a single-screw extruder, a T-die, and a cooling roll. 20 g of absorbent 2
m ^2, and a low-density polyethylene blended with 6% of titanium oxide so as to have a thickness of 50 μm from the extruder as a heat seal layer (1) (manufactured by Nippon Unicar Co., Ltd., trade name: NUC8007, melting point) 109 ° C, density 0.918g
/ Cm ² ) by extrusion lamination and thermocompression bonding by applying a mirror-finished cooling roll from the intermediate layer (22) side to obtain a multilayer film consisting of a heat seal layer (1) / intermediate layer (22). A barrier layer (3) obtained by dry laminating a nylon 6 film (15 μm) on a vapor-deposited surface of a silica-deposited PET film (12 μm) is applied to the intermediate layer (2) of the multilayer film.
2) Dry lamination was performed on the side to obtain an oxygen-absorbing multilayer film 3. The composition of the oxygen-absorbing multilayer film 3 is as follows: heat seal layer (1) (containing 6% by weight of titanium oxide); 50 μm / granular oxygen absorbent sandwiched between both films (20 g /
m ² ) / intermediate layer (22); 50 μm / nylon 6 film; 15 μm / silica-deposited PET film; 12 μm.

A packaging bag (10 cm × 15 cm) was prepared from the oxygen-absorbing multilayer film 3 so that the heat seal layer (1) was placed inside the packaging bag. In this bag, gelatin powder (water content 10% by weight, Aw 0.5) 5
After 0 g and 50 cc of air were sealed, the oxygen concentration in the bag was measured 3 days later, and found to be less than 0.1 vol%. When the package was stored at 23 ° C. for one month and opened,
Gelatin powder tasted good.

Example 4 Using a side-feed twin-screw extruder, the oxygen absorbent prepared in Example 1 was supplied by side-feed, kneaded with a molten linear low-density polyethylene, and oxygen was absorbed. Oxygen absorbent-containing pellets comprising 45% by weight of an agent and 55% by weight of a linear low-density polyethylene were prepared. Next, using a single-screw extruder, an extrusion laminator including a T-die and a cooling roll, a linear low-density polyethylene (manufactured by Nippon Polychem Co., Ltd.) containing 5% by weight of titanium oxide.
Trade name: Novatec UC470, melting point 126 ° C, density 0.924 g / cm ² ) 50 μm thick heat seal layer (1), containing the oxygen absorbent melted as an oxygen absorption layer (21) from a T-die. A multilayer film was obtained by extrusion laminating the pellets to a thickness of 30 μm. PE
T; 12 μm / aluminum foil; 9 μm barrier layer,
The multilayer film was dry-laminated on the oxygen absorbing layer (21) side to obtain an oxygen absorbing multilayer film 4. The oxygen-absorbing agent amount of this oxygen-absorbing multilayer film is about 20 g / m ² . The composition of the oxygen-absorbing multilayer film 4 is as follows: heat seal layer (containing 5% by weight of titanium oxide); 50 μm / oxygen absorption layer; 30 μm / aluminum foil; 9 μm / PET film;
12 μm. Further, when the cross section of the oxygen-absorbing multilayer film 4 was observed with a microscope, it was confirmed that the granular oxygen absorbent was uniformly dispersed throughout the oxygen-absorbing layer.

Next, a packaging bag (10 cm × 15 cm) was prepared from the oxygen-absorbing multilayer film 4 so that the heat seal layer was placed inside the packaging bag. In this bag, 50 Vitamin C tablets (water content 3% by weight, Aw 0.35)
g and 50 cc of air, and after 3 days, the oxygen concentration in the bag was measured to be 5.2 vol%.
It was less than 1 vol%. When this package was stored at 23 ° C. for one month and opened, no deterioration in the quality of the vitamin C tablet was observed.

[Comparative Example 1] A powder was prepared in the same manner as in Example 1, and calcium chloride was used as an accelerator for the particulate oxygen absorbent.
A multilayer film 11 was obtained. The configuration of the multilayer film 11 is as follows:
Heat seal layer (1) (containing 10% by weight of titanium oxide); 3
0 μm / granular oxygen absorber (30 g / m ² ) using calcium chloride sandwiched between both films (30 g / m ² ) / intermediate layer (2
2); 50 μm / aluminum foil; 9 μm / OPP film; 25
μm. Next, a packaging bag (1) made from the multilayer film 11 so as to arrange the heat seal layer (1) inside the packaging bag.
1 cm × 13 cm). In this bag, 50 g of a powder stock (water content 6% by weight, Aw 0.3) and air 5
0 cc was sealed, and the oxygen concentration in the bag was measured 3 days later. As a result, it was 18.5%, and there was no change in the oxygen concentration thereafter. When this package was stored at 23 ° C. for one month and opened, the flavor of the powdered stock was reduced.

Comparative Example 2 Commercially available PET / aluminum foil / LD
Packaging bag (10cm × 15c) using PE laminated film
m) was prepared. In this bag, 50 g of gelatin powder (water content 10% by weight, Aw 0.5), 50 cc of air
A self-reactive oxygen scavenger (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: Ageless Z-PT20) was sealed therein, and after 3 days, the oxygen concentration in the bag was measured and found to be less than 0.1%. Also,
When this package was stored at 23 ° C. for one month and opened, the gelatin powder had a good flavor and no discoloration was observed, but the gelatin powder was partially solidified in the bag.

[0043]

The oxygen-absorbing multilayer body of the present invention has excellent oxygen-absorbing performance under a low moisture environment. Further, the package made of the oxygen-absorbing multilayer body of the present invention is a low-moisture content preservation object such as powdered food, in a low-oxygen environment without the presence of a moisture donor, to reduce the quality and change in properties. Without coming
Can be stored in good condition.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of the oxygen-absorbing multilayer body of the present invention.

FIG. 2 is a sectional view showing an example of the oxygen-absorbing multilayer body of the present invention.

[Explanation of symbols]

 1: Heat seal layer X: Granular oxygen absorbent 21: Oxygen absorption layer 22: Intermediate layer 3: Gas barrier layer 4: Protective layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/08 C08K 3/08 3/16 3/16 C08L 23/00 C08L 23/00 (72) Inventor Yoshiki Ito 5-6-2, Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture F-term in Hiratsuka Research Laboratory, Mitsui Gas Chemical Co., Ltd. AA05B AA36B AB01B AB10C AK03A AK03B AK06A AK06B AK07A AK63A AK63B AR00C BA03 BA07 BA10A BA10C BA13 BA44 DE01B JA13A JA13B JB16A JB16B JD02C JD14B JL12A YY00B BB01 DAB4 DAB1A BB01

Claims (6)

[Claims] 1. A heat sealing layer made of a thermoplastic resin.
(1) From an oxygen-absorbing layer (21) made of an oxygen-absorbing resin composition obtained by mixing an oxygen-absorbing agent (X) with a thermoplastic resin bonded adjacent to the heat-sealing layer (1), and a gas barrier material. The heat-sealing layer (1) and the thermoplastic resin constituting the oxygen-absorbing layer (21) are polyolefins having a density of 0.940 or less, and the oxygen-absorbing agent An oxygen-absorbing multilayer body, wherein (X) is an oxygen-absorbing composition containing a reducing metal as a main component and a metal bromide or metal iodide as an oxygen absorption promoter. 2. A heat seal layer made of a thermoplastic resin.
(1) At least three of an oxygen absorbent (X), an intermediate layer (22) made of a thermoplastic resin bonded adjacent to the heat seal layer (1), and a gas barrier layer (3) made of a gas barrier material.
A layer, wherein the oxygen absorbent (X) is an oxygen-absorbing multilayer body in which the oxygen absorbent (X) is unevenly distributed on the joint surface between the layer (1) and the layer (22), and the oxygen absorbent (X) is mainly composed of a reducing metal. An oxygen-absorbing multilayer body comprising an oxygen-absorbing composition containing a metal bromide salt or a metal iodide salt as a promoter. 3. A heat sealing layer (1) and an oxygen absorbing layer (21).
2. The oxygen-absorbing multilayer body according to claim 1, wherein the thermoplastic resin constituting said low-density polyethylene or linear low-density polyethylene. 4. The oxygen-absorbing multilayer body according to claim 2, wherein the thermoplastic resin constituting the heat seal layer (1) and the intermediate layer (22) is made of low density polyethylene or linear low density polyethylene. 5. The method according to claim 1, wherein the oxygen absorption accelerator contained in the granular oxygen absorber (X) comprises a combination of (a) a metal bromide or metal iodide and (b) bromine or iodine. Oxygen absorbing multilayer body. 6. A packaging container using at least a part of the oxygen-absorbing multilayer body according to claim 1 or 2 in a packaging container.
A method for preserving low moisture content articles, which seals articles of 0% by weight or less.