JPH10338264A - Oxygen-absorbing laminate-packaging material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate packaging material which absorbs the residual oxygen left in the contents of a packaged food, and improves the reactive function of the food and prevents the deterioration of the contents during preservation and which is excellent in the pinhole-resistance of metallic foil and the appearance and further which is smooth on the surface. SOLUTION: This packaging material is laminated in the order of metallic foil layer/modified polyolefin layer/polyolefin layer containing iron powder/non- orientation polyolefin layer/, metallic foil layer/polyolefin layer/polyolefin layer containing iron powder/polyolefin layer. When the modified polyolefin is used during the lamination, after the modified polyolefin layer and the polyolefin layer containing iron powder have been fused and co-extruded, they are heated and fused once and thereafter, cooled and solidified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an oxygen-absorbing laminated packaging material. More specifically, it is a bag having a smooth surface and a good appearance for storing a food product formed by using the laminated packaging material, and prevents gas, air and the like from entering the bag from the outside, and the inside of the bag. Oxygen-absorbing laminate that absorbs the oxygen present in the bag and prevents deterioration of the food in the contents during the distribution and storage period, and does not impair or improve the texture when eating the food in the bag. Related to packaging materials.

[0002]

2. Description of the Related Art Conventionally, when packaging foods or the like, the oxidative deterioration of the foods, which are the contents, sometimes causes a decrease in the texture when eating the foods. In order to prevent this, a method of accommodating an oxygen scavenger together with food has been widely used for the purpose of improving storage stability. This oxygen absorber is usually stored in a small pouch, and is used, for example, in a packaging container at the same time as food packaging. However, consumers have complained to the manufacturer that the oxygen scavenger has been contaminated,
There was a possibility that the oxygen scavenger was accidentally eaten with the food, or the oxygen scavenging pouch was damaged and the content food was contaminated. Further, there is a disadvantage that an extra step of adding an oxygen scavenger is required in a product manufacturing process. In order to solve this, a packaging material having a deoxidizing function has been developed.

Japanese Patent Application Laid-Open No. 56-60642 discloses a laminate including a resin layer into which an oxygen scavenger has been kneaded. JP-A-60-158257 discloses an oxygen-absorbing resin composition in which a powder of an inorganic electrolyte material such as iron powder and a halide is uniformly mixed and filled in a thermoplastic resin.
However, such packaging materials have poor barrier properties and are not suitable for use as packaging materials for foods that need to be treated under high temperature and high humidity conditions such as retort sterilization.
Japanese Patent Application Laid-Open No. 8-72941 discloses a laminate including a barrier resin layer in addition thereto. As the barrier resin layer, an ethylene-vinyl alcohol copolymer, a vinylidene chloride resin, or the like is used. However, these barrier resins have reduced barrier properties during retort treatment, and cannot sufficiently fulfill their original intended function. In addition, since the resin layer in which the oxygen scavenger is dispersed and the barrier resin layer are usually laminated almost adjacent to each other, the oxygen scavenger in the resin is mixed in the barrier resin and reduces the oxygen absorbing ability.

[0004] In order to solve such a problem,
Techniques for dispersing a hygroscopic agent in a resin and techniques for laminating a polyolefin layer as a protective layer between a deoxidizer-dispersed resin layer and a barrier resin layer have been developed. JP-A-4-90
No. 848 discloses an iron powder having a specific surface area of 0.5 m 2 / g or more and an apparent density of 2.2 g / cm 2 or less and an oxygen absorbent serving as a metal halide. And a moisture absorbent are dispersed to suppress a decrease in the barrier function of the barrier resin layer at the time of retort sterilization or the like. Japanese Patent Application Laid-Open No. Hei 8-132573 discloses a deoxidizer-dispersed resin layer and a polyvinylidene chloride resin or ethylene. -Polyolefin is interposed between the oxygen-barrier resin layers, which does not depend on metal foil such as vinyl alcohol-based copolymers, to prevent the oxygen absorbing function from being mixed in the oxygen-barrier resin layers to prevent the oxygen absorption function from being impaired. . However, even with these techniques, the barrier property during retort sterilization treatment decreases,
The subsequent effect on oxygen absorption capacity cannot be completely reduced.

The use of a metal foil layer such as an aluminum foil as a barrier layer in order to suppress a decrease in barrier properties during retort sterilization and a decrease in oxygen absorption function is known from JP-B-61-32348. However, metal foil is liable to generate pinholes due to impact, etc.
In addition, there is a defect that the surface of the metal foil becomes uneven due to the effect of the particle size of the iron powder, thereby lacking smoothness, resulting in poor appearance and reduced commercial value.

[0006]

The oxygen barrier property is maintained during the retort treatment, the residual oxygen in the bag containing the food is absorbed, the texture of the food is improved during eating, and the oxygen sealed in the bag is improved. It is an object of the present invention to provide a laminated packaging material having a smooth surface and a good appearance by preventing deterioration of food contents during a storage period caused by the above.

[0007]

The inventors of the present invention have conducted intensive studies and have found that a specific 3 to 60 μm and an apparent density of 2.3 are obtained.
The present inventors have found that a bag containing a food product made of a laminated resin using iron powder of g / cm3 or more and iron powder having a size of 3 to 60 μm improves the flavor of the food product, and completed the present invention. That is, the present invention provides an oxygen-absorbing laminated packaging material comprising a metal foil layer / modified polyolefin resin layer / iron powder-containing polyolefin resin layer / unstretched polyolefin layer laminated in this order, metal foil layer / polyolefin resin layer / An oxygen-absorbing laminated packaging material, characterized by being laminated in the order of a polyolefin resin layer containing iron powder / a polyolefin layer,
When laminating a metal foil layer / modified polyolefin resin layer / iron powder-containing polyolefin resin layer / unstretched polyolefin resin layer, they are co-extruded and laminated.
3. The oxygen-absorbing laminated packaging material and the iron-containing polyolefin resin according to claim 1 and 2, which are subsequently heated and melted and then solidified by cooling, and a bag for retort food made from the material. A bag for dried food made from the oxygen-absorbing laminated packaging material according to 3 or 4, which is made of at least a thermoplastic resin, iron powder and an inorganic electrolyte substance, and has an apparent density of 2.3 g / An oxygen-absorbing iron powder-containing polyolefin resin composition having a size of 3 to 60 μm or more and a size of 3 to 60 μm and an inorganic electrolyte substance.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Metal foil layer / modified polyolefin resin layer / polyolefin resin layer containing iron powder / unstretched polyolefin layer or metal foil layer / polyolefin resin layer / polyolefin resin layer containing iron powder / polyolefin layer It was found that the problem could be solved by using a laminated packaging material characterized by the following facts. Further, a layer which is the outermost layer having a higher melting point than the modified polyolefin resin or the polyolefin resin layer and the polyolefin resin containing iron powder in the layer opposite to the modified polyolefin resin layer or the polyolefin resin layer of the metal foil layer of the packaging material. The same effect can be obtained by using a packaging material in which is laminated. Furthermore, in one of the processes for manufacturing these packaging materials, there is a process of laminating a metal foil, a modified polyolefin resin layer, and a polyolefin resin layer containing iron powder. It has also been found that a polyolefin resin layer is melt-coextruded, then heated and melted once, and then cooled and solidified to form a laminate.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The iron powder used in the polyolefin resin containing iron powder has an apparent density of 2.3 g / cm3 or more, and its specific surface area is not particularly limited. If the apparent density is 2.2 g / cm2 or less, there are drawbacks in terms of workability in handling the powder and efficiency in storage and transportation, which is not preferable. The average particle size of the iron powder affects the oxygen absorbing effect in the bag after the bag is made. The finer the finer, the higher the specific surface area, the greater the oxygen absorption.However, on the other hand, more advanced technologies are required for powder manufacturing technology, quality control until manufacturing such as oxidation resistance and disaster prevention management, and management in the manufacturing process. Required. Usually, a powder of 100 to 300 μm is used. On the other hand, it is preferable that the bag surface after bag making is smooth from the viewpoint of printing effect and aesthetic appearance. The particle size of the iron powder has an effect on the appearance. If the particle size is about 100 μm, it cannot be said that the surface has sufficient smoothness, the appearance is insufficient, and the printed surface has an unfavorable effect. In the present invention, since the powder of 3 to 60 μm is used, the gloss and the printed surface of the bag-making surface can be finely finished.

The amount of iron powder in the polyolefin resin containing iron powder may be an amount capable of absorbing all of the oxygen in the contents, and the size of the bag filled with food, the thickness of the polyolefin resin layer containing iron powder, Considering the content of oxygen, the amount of iron powder is preferably in the range of 0.1 to 45% by weight based on the polyolefin resin, but is not limited thereto.
If the content is less than 0.1% by weight, sufficient oxygen absorbing ability cannot be exhibited, and if the content is more than 45% by weight, there is a problem in workability in forming the same. As the polyolefin resin used in the iron powder-containing polyolefin resin used in the present invention, there is no need to use a special resin, and any generally available resin may be used. For example, low-, medium-, high-density polyethylene, polypropylene, polybutene, polypropylene-ethylene copolymer,
Examples include, but are not limited to, polypropylene-butene copolymer, polypropylene-ethylene-butene copolymer, and mixtures thereof.

As a method for dispersing the iron powder in the polyolefin resin, a usual method such as kneading with a twin screw extruder is used. At this time, in order to uniformly disperse the iron powder in the resin and improve processability, a general dispersant such as a silane coupling agent, a titanate coupling agent, a fatty acid or a salt thereof is added to the iron powder. You may add in the range of 0.1 to 10 weight%. Further, a filler such as activated carbon may be added in an average particle size suitable for the polyolefin resin layer to be obtained.

Although the iron powder has the oxygen absorbing function, the iron powder alone is not effective immediately, so an inorganic electrolyte substance is usually added as a catalyst. For example, halides are preferred,
In addition, alkali metals, alkaline earth metals, copper, zinc, aluminum, tin and the like are used. The halide must be present at or near the surface of the metallic iron in the thermoplastic resin. For this purpose, it is preferable to make the particle size of the halide smaller than the particle size of the iron powder and to devise a mixing method. In order to realize this, it is necessary to grind and mix the iron powder and the halide of 3 to 60 μm with a ball mill, a speed mill, a vibration mill or the like over a long time.

As the metal foil layer used in the present invention, aluminum foil is particularly preferably used in terms of moldability, cost and storage. In addition, an aluminum metal vapor-deposited film, an oxygen barrier film in which an oxide such as titanium, silicon, or zircon is vapor-deposited on a polyethylene terephthalate film or an O-nylon film can also be used.

The modified polyolefin resin is used as an adhesive binder between the metal foil and the polyolefin, and any resin may be used as long as it exhibits its effect. If exemplified, carboxyl group-containing polyolefin, or those having a metal compound disposed thereon, graphs and polymers of polyolefin and α, β-ethylenically unsaturated carboxylic acid or those having a metal compound disposed thereon, etc. However, the present invention is not limited to this. When a modified polyolefin resin is not used, an adhesive binder such as an anchor coat agent can be used.

The unstretched polyolefin or polyolefin described in the present invention is not particularly limited, and a general available one has sufficient effects.
The thickness is not limited. Further, the modified polyolefin resin layer of the metal foil or the layer to be the outermost layer laminated on the side opposite to the polyolefin resin layer may be anything as long as it has a higher melting point than the modified polyolefin resin or polyolefin resin layer and the unstretched polyolefin, Examples include, but are not limited to, plastic films such as polyethylene terephthalate, polyethylene naphthalate, and nylon, metal-deposited films thereof, and paper. These layers are printed on the side opposite to the outermost side or on the surface, and the printing method is not particularly limited, and ordinary gravure printing, offset printing, flexographic printing, etc. A method can be used. Also, these layers need not be laminated by a special method, and can be laminated by a usual method such as dry lamination or extrusion lamination.

When the above-mentioned modified polyolefin resin or polyolefin resin containing iron powder is formed into a film, it is not necessary to use a specific die.
It can be performed by employing an extrusion molding method using a mold die.

The laminated packaging material of the present invention may be obtained by laminating a metal foil, the above-mentioned modified polyolefin resin, a polyolefin resin containing iron powder, and an unstretched polyolefin layer. The powdered polyolefin resin layer is heated and melted once after co-extrusion processing, and then cooled and solidified, so that the barrier property does not decrease during the retort sterilization treatment, the functionality of the content food is improved, and packaging material with good storage stability Can be obtained. Further, by performing such a heat treatment, the generation of pinholes against the impact of the metal foil can be suppressed, and the surface of the metal foil layer can be further smoothed without being affected by iron powder. Since the present invention uses a modified polyolefin resin when laminating a metal foil and a polyolefin resin, there is no need to use a thermosetting adhesive or the like that may be eluted during the retort treatment, and the content of the food is reduced by these. No decrease in the organoleptic function occurs. Further, in this case, there is no need to apply an anchor coat agent for imparting adhesiveness when laminating the metal foils, so that there are advantages in terms of workability and cost. When laminating such a packaging material of the present invention, it is necessary to perform the heat treatment step for heating and melting the modified polyolefin resin at the time of lamination or after lamination. In consideration of the effect of the outermost layer, it is preferable to laminate the outermost layer after heat-treating the metal foil layer and the polyolefin resin layer containing the iron powder via the modified polyolefin resin layer. Regarding the heat treatment temperature, the melting point of the polyolefin resin containing iron powder is around 100 to 165 ° C., and the melting point of the unstretched polyolefin layer to be laminated is 100 to 16 ° C.
Since the temperature is 5 ° C., the temperature of the polyolefin resin layer, which is the layered structure of the laminated body to be heated, is equal to or higher than the above melting point, that is, 110 to 1 in accordance with the polyolefin resin to be used.
It must be above 70 ° C. Although the time is not particularly limited, it is necessary to avoid conditions that cause deterioration of the polyolefin resin. As a method for heating the above-mentioned laminate, a hot roll is preferable, and a heat oven, an infrared heater or the like can also be used. Although there is no particular limitation on the cooling method, good results can be obtained by cooling with a metal roll.

The dry food in the present invention may be any food in a dry state, and includes not only ordinary dry foods but also semi-dry foods. For example, dried scallops, processed sardines, beef jerky, mixed nuts, grilled laver, peanuts, almonds, potato chips, powdered instant coffee, dried noodles, powdered instant soup,
Examples include, but are not limited to, dried shiitake mushrooms, downstream seasonings consisting of fish knot powder and monosodium glutamate, shaved fish knots, boiled, kelp powder, skim milk powder, and the like.

When the thus obtained laminated packaging material is made into a bag body with the unstretched polyolefin layer inside, and the contents are filled and subjected to retort sterilization, the crystal form of the polyolefin resin layer changes. The resulting distortion between the crystals does not occur, and the degree of orientation hardly changes, so that the appearance is good with almost no occurrence of surface breakage, edge breakage, and pinholes.Also, the dispersed iron powder can be mixed into the barrier layer. In addition, oxygen in the content is absorbed by the iron powder, the sensory of the content food is improved, and deterioration over time during the storage period can be suppressed.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

Preparation method of polyolefin film containing iron powder: Iron powder and inorganic electrolyte are mixed, and the obtained mixed powder and polyolefin resin are melt-kneaded by a twin-screw extruder and then pelletized by a pelletizer. A polyolefin resin containing iron powder was obtained. The polyolefin resin containing the iron powder was melted and a film was formed with a T die. The laminated product was subjected to lamination simultaneously with the melt processing of the polyolefin resin pellets containing iron powder.
Oxygen concentration measurement method of iron powder-containing polyolefin single film: The obtained iron-containing film was sealed in an aluminum pouch and adjusted to a predetermined headspace air volume.
The solution was stored at 80 ° C. and 80% RH, and the oxygen concentration was measured after 3, 7, and 10 days. Evaluation of appearance goodness: The overall appearance was visually evaluated by a panel in three steps. Content sensory evaluation of food: Overall sensory was evaluated by a panelist on a five-point scale.

[0022]

Example 1 Specific surface area 0.3 m2 / g, apparent density 2.
7 g / cm 3, 254 parts by weight of iron powder having an average particle size of 10 μm and 48 parts by weight of calcium chloride having an average particle size of 2 mm were ground and stirred by a bead mill until the average particle size became 10 μm. After 46 parts by weight of the obtained mixed powder and 410 parts by weight of a polyethylene resin (Japan Polyolefin Jex) are melt-kneaded by a twin-screw extruder and kneaded, the mixture is pelletized by a pelletizer, and a polyethylene resin pellet containing iron powder is obtained. Obtained. Further, the pellet was melt-extruded into a 30 μm film with a T-die, and then 3.6 g of the obtained polyethylene film containing iron powder was cut out. Next, after wetting the film, it was sealed in an aluminum pouch, the content air content was adjusted to 216 ml, stored at 24 ° C. and 80% RH, and the oxygen concentration of the content air was measured. Also,
Evaluation of the film forming property and the good appearance of the obtained iron powder-containing film was performed in three grades of ○, ×, and Δ.

[0023]

Example 2 Average particle size 2 mm instead of calcium chloride
The same operation as in Example 1 was performed except that 20 parts by weight of magnesium chloride was added. [Example 3] The pellets of the polyethylene containing iron powder obtained in Example 2 were melt-extruded and laminated with a T-die, and finally, a laminated packaging material having the following configuration, which was printed on the surface, was obtained. . Printing layer / bleached kraft paper / polyethylene (15μ) / aluminum foil (7μ) / adhesive layer / polyethylene (15μ) / polyethylene with iron powder (30μ) /
Polyethylene (15μ). The same evaluation as in Example 1 was performed using this laminated packaging material.

[0024]

Comparative Example 1 An iron powder having a specific surface area of 0.3 m2 / g, an apparent density of 2.7 g / cm3, and an average particle diameter of 200 μm was used.
The same operation as in Example 1 was performed except that the mixture was pulverized and stirred until it became μ.

[0025]

Comparative Example 2 Using iron powder having a specific surface area of 0.7 m2 / g, an apparent density of 1.8 g / cm3, and an average particle diameter of 10 μm, a method of mixing iron powder and calcium chloride was stirred for 15 minutes using a Henschel mixer. The same operation as in Example 1 was performed except that only the operation was performed.

[0026]

Comparative Example 3 Iron powder having a specific surface area of 0.3 m 2 / g, an apparent density of 2.7 g / cm 3 and an average particle size of 200 μm was used.
Example 1 using a mixed powder crushed and stirred until it became μ
Thus, polyethylene pellets containing iron powder were obtained. Using these pellets, a laminated packaging material having the following configuration was obtained in the same manner as in Example 3. Printing layer / bleached kraft paper / polyethylene (15μ) / aluminum foil (7μ) / adhesive layer / polyethylene (15μ) / polyethylene with iron powder (30
μ) / polyethylene (15μ). The same evaluation as in Example 1 was performed using this laminated packaging material.

[0027]

Example 4 The bleached kraft paper of the laminated packaging material obtained in Example 3 was impregnated with 10 g of water per 1 m 2, immediately wound up in a roll, degassed and sealed, and stored at 25 ° C. for 7 days. Thereafter, using this laminated packaging material, a polyethylene layer was disposed on the innermost layer, and mixed nuts were stored therein.
Create a bag of 0cm x 25cm, 24 ℃, 80% RH
And evaluated by a five-level sensory evaluation of the contents by an evaluation panel and the three-level evaluation of o, x, and △.

[0028]

Comparative Example 4 Using iron powder having a specific surface area of 0.7 m2 / g, an apparent density of 1.8 g / cm3, and an average particle size of 10 μm, a method of mixing iron powder and calcium chloride was stirred for 15 minutes using a Henschel mixer. The same evaluation as in Example 4 was performed except that only the evaluation was performed.

[0029]

Comparative Example 5 Iron powder having a specific surface area of 0.3 m 2 / g, an apparent density of 2.7 g / cm 3 and an average particle size of 200 μm was used.
The same operation as in Example 4 was performed except that the mixture was pulverized and stirred until it became μ.

[0030]

Comparative Example 6 A bleached kraft paper having a printed surface and an aluminum foil were laminated by extrusion lamination, and then polyethylene was laminated through an adhesive layer to obtain a packaging material having the following packaging material configuration. Was. Printing layer / blown kraft paper / polyethylene (15μ) / aluminum foil (7μ) / adhesive layer / polyethylene (60μ). Thereafter, the same evaluation as in Example 4 was performed using this laminated packaging material.

[0031]

Example 5 Specific surface area 0.3 m2 / g, apparent density 2.
159 parts by weight of a flat iron powder having an average particle diameter of 7 g / cm 3 and an average particle diameter of 10 μm and 8 parts by weight of sodium chloride having an average particle diameter of 2 mm were pulverized and stirred by a bead mill until the average particle diameter became 10 μm. 8 parts by weight of the obtained mixed powder and polypropylene resin (Japanese polyolefin show aroma) 6
After melt-kneading 5 parts by weight with a twin-screw extruder and kneader, pelletizing was performed with a pelletizer to obtain a polypropylene resin containing iron powder. Next, 60 μm of a non-stretched polypropylene film (CPP) (TOCELLO RXC-11) and 7 μm of aluminum foil (Showa Aluminum IN30) are applied through a co-extrusion layer of an acid-modified polyolefin resin (Nippon Polyolefin Adtech) and the polypropylene resin containing iron powder. This laminate is treated for 1 second on a heat roll at a temperature such that the temperature of the polypropylene resin layer containing iron powder, which is a constituent layer thereof, becomes 200 ° C. so that the aluminum foil side is in contact with the roll surface. Cooling was performed using a chill roll at 25 ° C. Furthermore, 12 μm of polyethylene terephthalate film (PET) (Toyobo Espet Film) and 15 μm of nylon (Ny) (Idemitsu Petrochemical Unilon), which are printed as the outermost layer via an adhesive made of a thermosetting resin, are then applied to an aluminum foil layer. Was laminated on the side to obtain a laminated packaging material. The layer structure and thickness of the obtained packaging material were as follows. PET (12μ) / printing layer / adhesive layer / N
y (15μ) / adhesive layer / aluminum foil (7μ) / acid-modified polypropylene resin (3μ) / polypropylene resin containing iron powder (25μ) / CPP (60μ). Next, the CPP side of the obtained packaging material was placed on the innermost layer, and 15 cm × 20 cm.
cm bag, filled with sweet and sour pork as content food 1
A retort sterilization treatment was performed at 25 ° C. for 10 minutes. After that, the bag was stored at 24 ° C. and 80% RH, and a five-level sensory evaluation of the contents by an evaluation panelist and a good appearance of the bag were evaluated as ○,
×, evaluated in three-step evaluation

[0032]

Comparative Example 7 Using iron powder having a specific surface area of 0.7 m2 / g, an apparent density of 1.8 g / cm3, and an average particle size of 10 μm, a method of mixing iron powder and sodium chloride was stirred for 15 minutes using a Henschel mixer. The same operation as in Example 5 was performed except that only the operation was performed. [Comparative Example 8] Specific surface area of 0.3 m2
/ G, apparent density 2.7 g / cm3, average particle size 20
The same operation as in Example 5 was performed except that iron powder having a particle diameter of 0 μm was pulverized and stirred with calcium chloride and a bead mill until the average particle diameter became 200 μm.

[0033]

Comparative Example 9 Unstretched polypropylene film (CPP) using the polypropylene powder containing iron powder obtained in Example 5
(TOCELLO RXC-11) 60μ, polypropylene resin layer containing iron powder, ethylene-vinyl alcohol copolymer layer (E
VOH) (Kuraray Eval EP-E105) was laminated via an adhesive layer. After that, 12 μm of polyethylene terephthalate film (PET) (Toyobo Espet Film) and 15 μm of nylon (Ny) (Idemitsu Petrochemical Unilon), which are printed as the outermost layer via an adhesive made of a thermosetting resin, are mixed with ethylene-vinyl. This was laminated on the alcohol copolymer layer side to obtain a laminated packaging material. The layer structure and thickness of the obtained packaging material were as follows. PET (12
μ) / printing layer / adhesive layer / Ny (15μ) / adhesive layer /
EVOH (20μ) / adhesive layer / polypropylene resin containing iron powder (25μ) / CPP (60μ). Next, a bag was prepared by disposing the CPP side of the obtained packaging material in the innermost layer, and the same operation as in Example 5 was performed.

[0034]

Comparative Example 10 Aluminum foil (Showa Aluminum 11
00) 7 μ and undrawn polypropylene (CPP) (TOCELLO RXC-11) 60 μ were laminated via an adhesive layer.
In addition, polyethylene terephthalate (PE) printed on the opposite side of the aluminum foil from the unstretched polypropylene layer
T) A packaging material was obtained by laminating 12 μm of a film (Toyobo Espet Film) and 15 μm of nylon (Ny) (Idemitsu Petrochemical Unilon) via an adhesive layer. The layer structure and thickness of the obtained packaging material were as follows. PET (12
μ) / printing layer / adhesive layer / Ny (15μ) / adhesive layer /
Aluminum foil (7μ) / adhesive layer / CPP (60
μ). Next, a bag was prepared by disposing the CPP side of the obtained packaging material in the innermost layer, and the same operation as in Example 5 was performed. Table 1 shows the measurement results of the oxygen concentrations of Examples 1 to 3 and Comparative Examples 1 to 3.
Table 2 shows the evaluation results of the film forming property and the good appearance of the film.
Was compared to Furthermore, the results of the five-stage sensory evaluation of Example 4 and Comparative Examples 4 to 6 and the three-stage evaluation of the good appearance of the bag are shown in Table 3, and the five-stage sensory evaluation of Example 5 and Comparative Examples 7 to 10 Table 4 shows the results of the three-level evaluation of the good appearance of the bag.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

[0038]

[Table 4]

[0039]

According to the present invention, since the metal foil layer is used as the barrier layer of the laminated packaging material, the deterioration of the barrier property at the time of the retort treatment does not occur, and the deterioration due to the decrease of the barrier property after the retort of the contents is reduced. Absent. When a modified polyolefin is laminated thereon, a pretreatment step such as an anchor coating agent can be omitted, and the workability is improved. In addition, by laminating a polyolefin resin containing iron powder, it is possible to absorb the residual oxygen in the contents without mixing the iron powder into the barrier layer and without affecting the oxygen absorption capacity, thereby improving the sensuality, It is possible to suppress deterioration over time of the content food during the storage period. In addition, when the modified polyolefin resin is used, there is no decrease in functionality due to elution of the urethane adhesive or the like during the retort treatment. Furthermore, when using a modified polyolefin in the manufacturing process, the modified polyolefin resin layer and the polyolefin resin layer containing iron powder are co-extruded, then heated and melted once, and then cooled and solidified to suppress the occurrence of pinholes in the metal foil. However, the surface can be smoothed to improve the appearance. Thus, the laminated packaging material of the present invention,
Since the content of the food can be improved and the appearance can be improved and the deterioration of the content during storage can be suppressed, the original flavor and taste of the content food can be utilized.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Eiichi Nishi 1-1, Suzukicho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Ajinomoto Co., Ltd. 6-1 Inside Ace Package Co., Ltd. (72) Inventor Takeshi Fukumoto 6-1 Minatomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside Ace Package Co., Ltd.

Claims (11)

[Claims] 1. An oxygen-absorbing laminated packaging material comprising: a metal foil layer / modified polyolefin resin layer / iron powder-containing polyolefin resin layer / unstretched polyolefin layer laminated in this order. 2. An oxygen-absorbing laminated packaging material comprising: a high melting point resin layer / adhesive layer / metal foil layer / modified polyolefin resin layer / iron powder-containing polyolefin resin layer / unstretched polyolefin layer laminated in this order. . 3. An oxygen-absorbing laminated packaging material comprising a metal foil layer / polyolefin resin layer / iron powder-containing polyolefin resin layer / polyolefin layer laminated in this order. 4. An oxygen-absorbing laminated packaging material which is laminated in the order of paper / polyolefin layer / metal foil layer / polyolefin resin layer / polyolefin resin layer containing iron powder / polyolefin layer. 5. When laminating at least a metal foil layer / modified polyolefin resin layer / iron powder-containing polyolefin resin layer / unstretched polyolefin resin layer, they are co-extruded and laminated, then heated and melted, and then cooled and solidified. The oxygen-absorbing laminated packaging material according to claim 1 or 2, wherein 6. The iron powder in the polyolefin resin layer containing the iron powder is an iron powder having an apparent density of 2.3 g / cm 3 or more and a size of 3 to 60 μm, and further contains an inorganic electrolyte substance of 3 to 60 μm in size. The oxygen-absorbing laminated packaging material according to any one of claims 1 to 4. 7. A bag molded using the laminated packaging material according to claim 1 or 2, wherein an unstretched polyolefin is the innermost layer. 8. A bag formed using the laminated packaging material according to claim 3, wherein the innermost layer is a polyolefin. 9. A bag for a retort food containing a retort-compatible food as the contents of a bag molded using the laminated packaging material according to claim 1 or 2, wherein the innermost layer is a non-stretched polyolefin. 10. The polyolefin as the innermost layer.
5. A bag for dry food containing a dry food as a content of the bag molded using the laminated packaging material according to any one of items 4 to 4. 11. An iron powder having an apparent density of 2.3 comprising at least a thermoplastic resin, iron powder and an inorganic electrolyte substance.
g / cm3 or more, a size of 3 to 60 um, and a size of an inorganic electrolyte substance of 3 to 60 um.