JPH11240095A - Deoxidizing multilayer film - Google Patents

Abstract

(57) [Problem] To provide a deoxidizing multilayer film having an excellent oxygen absorption rate. SOLUTION: At least three layers in which a gas barrier layer, an oxygen-absorbing resin layer made of a deoxidizing resin composition in which an oxygen agent composition is dispersed in a thermoplastic resin, and an isolation layer made of a thermoplastic resin are laminated in this order. In the oxygen-absorbing multilayer film consisting of, either or both of the oxygen-absorbing resin layer and the thermoplastic resin constituting the isolation layer are made of a metallocene-catalyzed polyethylene alone or a mixed resin with another thermoplastic resin. A deoxidizing multilayer film characterized by the following.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer film having a deoxidizing function and a packaging container comprising the same. Specifically, the oxygen-absorbing multilayer film using a metallocene-catalyzed polyethylene for one or both of the thermoplastic resin constituting the oxygen-absorbing resin layer and the isolating layer, and has a superior oxygen absorption rate as compared with the related art. The present invention relates to a deoxidizable multilayer film capable of exerting a function and a packaging container comprising the same.

[0002]

2. Description of the Related Art In recent years, as a package for preventing oxidative corrosion of an article, it has been considered that the package is made of a packaging material having a deoxidizing function. A so-called deoxidizing multilayer body having a resin layer as an intermediate layer has been developed. Of these, the total thickness is a thin film-shaped oxygen-releasing multilayer body, so-called oxygen-releasing multilayer film,
It is used as a bag having a deoxygenation function, or as a top film of a barrier container, or as a material for absorbing oxygen remaining in the bag or the container.

[0003] Oxygen-desorbable multilayer films are transparent from the outside,
Basically, three layers are stacked in this order: a gas barrier layer that blocks oxygen entering, an oxygen-absorbing resin layer obtained by dispersing an oxygen-absorbing composition in a thermoplastic resin, and an isolation layer made of a thermoplastic resin. Coating, or extrusion coating, which is laminated by extruding heat-melted resin pellets, or various laminates, which are laminated in advance through an adhesive or an adhesive resin. It is manufactured using. As the thermoplastic resin constituting the oxygen-absorbing resin layer and the isolating layer of the oxygen-absorbing multilayer film, polyolefins are preferably used from the viewpoint of hygiene, versatility, and processability, and among these, polyethylene is widely used. ing.

[0004]

Conventionally, as a polyethylene constituting an isolation layer or an oxygen-absorbing resin layer of a deoxidizing multilayer film, a low-density polyethylene (hereinafter referred to as a polyethylene) produced by a high-pressure method using a radical initiator as a catalyst. , LDP
E) or a linear low-density polyethylene (hereinafter, LLDPE) or high-density polyethylene (hereinafter, HDPE) produced by a solution method, a gas phase method, or the like using a Ziegler catalyst or a Phillips catalyst. . LDPE is mainly used for applications requiring hygiene, LLDPE is used mainly for applications requiring mechanical properties such as hot tack, contaminant sealing, heat sealing strength, impact strength, etc.HDPE is heat sterilized It is a material suitable for the application, and is properly used depending on the type of the contents to be stored.

[0005] The characteristic of the oxygen-absorbing multilayer film obtained by dispersing the oxygen-absorbing composition inside the film is that it absorbs oxygen. In the process, oxygen passes through the isolating layer of the oxygen-absorbing multilayer film, reaches the oxygen-absorbing resin layer, and further passes through the thermoplastic resin constituting the oxygen-absorbing resin layer, and is dispersed in the oxygen-absorbing resin layer. In order to realize a rapid oxygen absorption rate, oxygen is quickly transmitted to the oxygen absorbing composition in the oxygen absorbing resin layer. In short, the isolation layer and the oxygen absorbing material are absorbed by the oxygen absorbing composition. It is an essential element that the thermoplastic resin constituting the conductive resin layer has high oxygen permeability. However, as a material for forming the oxygen-absorbing resin layer or the isolation layer of the deoxidizing multilayer film, LDPE, LLDP
When E or HDPE is used, there is a problem that a practical oxygen absorption rate may not be obtained due to low intrinsic oxygen permeability. In order to use these materials as materials constituting the oxygen-absorbing resin layer and the isolating layer and to quickly absorb oxygen inside the package, it is considered as effective means to reduce the thickness of the isolating layer. . However, if the thickness of the separation layer is made unnecessarily thin in order to improve the oxygen permeability, workability, physical properties such as heat sealability are reduced, or the oxygen absorbing composition in the oxygen-absorbing resin layer is further reduced. It is not a preferable means because the contents may be exposed to the surface of the separating layer and contaminated by the oxygen scavenger composition. As another means, a method of blending a high oxygen-permeable resin such as polymethylpentene with a thermoplastic resin constituting the isolation layer or the oxygen-absorbing resin layer can be considered, but the processability is reduced or the cost is increased. In many cases, it was not a preferable means. Therefore, when a conventional oxygen-absorbing multilayer film using LDPE, LLDPE, or HDPE as an isolation layer or an oxygen-absorbing resin layer is used for part or all of a packaging bag, the use is often limited. .

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and has a practically high oxygen-absorbing property capable of exhibiting an excellent oxygen absorption rate as compared with a conventional multilayer film having an oxygen-absorbing function. It is intended to provide a multilayer film and a packaging container comprising the same.

[0007]

Means for Solving the Problems In view of the above-mentioned problems of the prior art, the present inventors have conducted intensive studies on a deoxidizing multilayer film capable of exhibiting an excellent oxygen absorption rate, and as a result, have found that the above-mentioned problems have been solved. By using a metallocene-catalyzed polyethylene for one or both of the thermoplastic resin constituting the layer and the oxygen-absorbing resin layer, it can exhibit an excellent oxygen absorption rate as compared with the conventional oxygen-absorbing multilayer film. The inventors have found that this is possible and completed the present invention.

That is, according to the present invention, a gas barrier layer, an oxygen-absorbing resin layer composed of an oxygen-absorbing resin composition in which an oxygen-absorbing composition is dispersed in a thermoplastic resin, and an isolation layer composed of a thermoplastic resin are laminated in this order. In the oxygen-absorbing multilayer film composed of at least three layers, one or both of the oxygen-absorbing resin layer and the thermoplastic resin constituting the isolation layer may be a metallocene-catalyzed polyethylene alone or with another thermoplastic resin. The present invention relates to a deoxidizing multilayer film comprising a mixed resin.

Further, the oxygen-absorbing multilayer film of the present invention is characterized in that the content of polyethylene by a metallocene catalyst in the thermoplastic resin constituting the oxygen-absorbing resin layer and / or the isolating layer is 10 to 100% by weight. Features.

Further, the oxygen-absorbing multilayer film of the present invention has a metallocene-catalyzed polyethylene alone or mixed with another thermoplastic resin constituting the oxygen-absorbing resin layer having an oxygen transmission coefficient at 25 ° C. of 250 cc. mm / m ²・
atm.day or more.

Further, the oxygen-absorbing multilayer film of the present invention is characterized in that the isolation layer composed of a metallocene-catalyzed polyethylene alone or a mixed resin with another thermoplastic resin has a temperature of 25 ° C.
Oxygen permeability at 3500 cc / m ² · atm · day
It is characterized by the above.

The present invention also relates to a packaging container in which at least a part of the packaging container is made of the oxygen-absorbing multilayer film according to the first aspect of the present invention, and has an isolation layer inside to absorb oxygen in the packaging container. Here, the packaging container refers to a packaging container of various shapes such as a bag or a cup, which is filled with food or the like and sealed to form a package, which is used for long-term storage of food or the like.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The metallocene-catalyzed polyethylene used in the present invention (hereinafter abbreviated as metallocene polyethylene) has a structure in which a transition metal catalyst is sandwiched between unsaturated cyclic compounds, and is a homogeneous solvent-soluble solvent. Refers to a polyethylene produced by a gas phase method or a solution method using a metallocene catalyst which is a compound of Metallocene polyethylene has physical properties such as impact strength, hot tack property, impurity sealing property, heat sealing strength and the like, which are equal to or higher than those of conventional LLDPE, and its molecular weight distribution is relatively monodisperse. It has good extrusion stability and low odor since it has few high molecular weight components and volatile components. Another characteristic of metallocene polyethylene is that oxygen permeability is higher than polyethylene such as conventional LDPE and LLDPE. From these characteristics, metallocene polyethylene has preferable characteristics as a material constituting the isolation layer or the oxygen-absorbing resin layer of the multilayer film having a deoxidizing function of the present invention.

In the oxygen-desorbing multilayer film of the present invention, a metallocene polyethylene having a higher oxygen permeability than conventional polyethylene can be used alone or with another heat-generating material in order to develop a faster oxygen absorption rate than before. It is mixed with a plastic resin and used for only the isolation layer, only the oxygen-absorbing resin layer, or both the isolation layer and the oxygen-absorbing resin layer. In addition, it is preferable to select the usage depending on the performance required for the package using the deoxidizing multilayer film. For example, in applications that require a faster oxygen absorption rate than conventional oxygen-absorbing multilayer films, adopting an oxygen-absorbing package using metallocene polyethylene for the isolating layer can isolate oxygen in the bag. Oxygen is efficiently transmitted through the layer and oxygen is rapidly absorbed by the oxygen-absorbing resin layer. Further, by using metallocene polyethylene for both the isolation layer and the oxygen-absorbing resin layer, it is possible to more quickly absorb oxygen. In applications such as heat sterilization, LL may be added to the isolation layer.
A heat-resistant material such as DPE or HDPE is used, and metallocene polyethylene is used for the oxygen-absorbing resin layer.
By adopting such a form, the oxygen permeability of the thermoplastic resin constituting the oxygen-absorbing resin layer is improved, so that a higher oxygen absorption rate can be exhibited as compared to the conventional oxygen-absorbing multilayer film, and heat resistance. Can be obtained.

In the deoxidizing multilayer film of the present invention, one or both of the thermoplastic resin constituting the isolating layer and the oxygen-absorbing resin layer may be provided with metallocene polyethylene alone or in a range not impairing oxygen permeability. Used in combination with a thermoplastic resin. At this time, the content of the metallocene polyethylene in the thermoplastic resin constituting the isolation layer or the oxygen-absorbing resin layer is preferably 10 to 100% by weight, more preferably 30 to 100% by weight. If the metallocene polyethylene content is less than 10% by weight, oxygen permeability is reduced, and a practical oxygen absorption rate cannot be exhibited. Other thermoplastic resins combined with metallocene polyethylene include LDPE, LLDPE, HDPE, polypropylene, ethylene-α-olefin copolymer, ethylene-acrylic acid (or methacrylic acid) copolymer, ethylene-maleic anhydride copolymer, Examples include ethylene-vinyl acetate copolymers, ionomers, polyolefins such as polybutene and polymethylpentene, graft polymers with silicone resins, polyesters such as polyethylene terephthalate, polyamides such as nylon 6, nylon 66, and thermoplastic elastomers. However, two or more of these may be used in combination. Of these, various polyethylenes are preferably used in terms of versatility, hygiene, processability, and compatibility with metallocene polyethylene. In addition, the isolation layer may be a single layer of the above resin or a multilayer of two or more layers, or a nonwoven fabric or a microporous membrane having fine pores formed of these resins may be used. The constituent material and form of the isolation layer are not limited to the above, and various forms can be adopted.

The isolating layer of the deoxidizing multilayer film of the present invention is composed of one or more layers, and is required to be capable of efficiently transmitting oxygen. The oxygen permeability is 3 regardless of the number and thickness of the layers.
500 cc / m ² · atm · day or more is preferable, and 4
It is more preferably at least 000 cc / m ² · atm · day. Oxygen permeability is 3500cc / m ² · atm · day
If it is lower, the oxygen permeation of the isolation layer becomes rate-determining with respect to the oxygen absorption performed in the oxygen-absorbing resin layer, and the oxygen absorption rate decreases, which is not preferable.

The isolating layer is a layer having a role of isolating the oxygen-absorbing resin layer from the stored material and a role of a sealant, and preferably has a thickness of 10 to 100 μm, more preferably 20 to 80 μm. If the thickness of the isolation layer is less than 10 μm, the processability at the time of laminating is reduced, and the oxygen absorbing composition in the oxygen-absorbing resin layer may be exposed on the surface of the isolation layer and contaminate the stored items. And the physical properties such as the heat sealability of the obtained deoxidizing multilayer film are undesirably reduced. On the other hand, if the thickness is more than 100 μm, the oxygen permeability of the isolation layer is reduced, and the total thickness of the deoxidizing multilayer film is increased.

In the separating layer, if necessary, pigments for hiding and coloring, dispersants such as silanes and titanates, antioxidants, fillers such as clay, mica, silica, calcium carbonate, activated carbon, etc. Adsorbent can be added. In the present invention, coloring the isolation layer is preferably performed for the purpose of concealing the oxygen-absorbing resin layer. In addition, when there is a concern that the function as a sealant may be reduced by adding a pigment, it is effective to make the structure of the isolation layer a multilayer including a layer containing no pigment and a layer to which the pigment is added. Means. Note that the various additives are not limited to those exemplified above, and various additives can be used.

The oxygen-absorbing resin layer is composed of an oxygen-absorbing resin composition obtained by dispersing an oxygen-absorbing composition in a thermoplastic resin.
Has the role of absorbing oxygen. In order to exhibit excellent oxygen absorption performance, efficient oxygen permeation performance is required. The oxygen permeability coefficient of the thermoplastic resin constituting the oxygen-absorbing resin layer is 250 cc · mm / m ² · atm · day. More preferably, 300 cc · mm / m ² · atm · da
y or more is more preferable. Oxygen permeability coefficient is 250cc ・ m
If it is lower than m / m ² · atm · day, the oxygen absorption rate decreases, which is not preferable.

The oxygen-absorbing composition dispersed in the thermoplastic resin of the oxygen-absorbing resin layer includes a so-called moisture-dependent oxygen-absorbing composition which causes a deoxygenation reaction when supplied with water. Used as granules. As the granular oxygen absorber composition, a granular substance is selected as a reducing substance serving as a main agent of a deoxygenation reaction, and the surface of the granular main agent is coated with an oxygen absorber composition other than the main agent such as an auxiliary agent, Alternatively, a mixture obtained by mixing all the oxygen scavenger compositions such as the reducing agent of the main agent and then granulating the mixture is preferably used.

Examples of the oxygen scavenger composition include metal powders such as iron powder, aluminum powder and silicon powder, inorganic salts such as ferrous salts and dithionite, and reducing substances such as organic substances such as catechol and glycerin. And a base material. In particular, a deoxidizer composition containing a metal powder as a main component is preferable, for example,
A metal powder which can be produced by the method disclosed in Japanese Patent No. 1088514, in which a metal halide is attached to the surface, or a metal powder and a metal halide, and if necessary, other additives are granulated as a binder. Those that have been used are preferably used.

In the oxygen scavenger composition of the metal powder base,
The metal powder is preferably iron powder. The purity of the iron powder is not particularly limited, and may be partially oxidized or may be an alloy with another metal, which can cause an oxygen absorption reaction and can be easily dispersed in a thermoplastic resin. Anything is fine. For example,
Iron powder represented by reduced iron powder, spray iron powder, electrolytic iron powder,
Pulverized products of various iron products such as cast iron and steel, and ground products are preferably fine particles or fibrous materials. The average particle size of the particulate metallic iron is preferably 50 μm or less. In the case of fibrous metallic iron, it is preferable that the diameter and length be as small as possible for the same reason.

The metal halide acts catalytically on the oxygen absorption reaction of metallic iron in the thermoplastic resin. Examples of the metal halide include an alkali metal, an alkaline earth metal, copper, zinc, aluminum, tin, iron, cobalt and nickel, and at least one selected from chlorides, bromides, and iodides. potassium,
Preference is given to chlorides of the group consisting of sodium, magnesium, calcium, barium, iron.

The proportion of the metal halide is preferably 0.1 to 10 parts by weight per 100 parts by weight of metallic iron. When substantially all of the metal halide adheres to the metallic iron and there is almost no free metal halide in the thermoplastic resin, and when the metal halide works effectively, it is 0.1 to 5% by weight. Department is enough.

It is desirable that the metal halide be added in the thermoplastic resin in such a manner that it does not easily separate from the metallic iron. Examples of the method of attaching the metal halide to the metal iron include, for example, a method of crushing and mixing using a ball mill, a speed mill, or the like, embedding metal iron halide fine particles in recesses on the metal iron surface, and a method using a binder. Particularly preferred is a method in which metal halide fine particles are adhered to a metal, or a method in which a metal halide aqueous solution and metal iron are mixed and dried to adhere metal halide fine particles to the metal iron surface.

The water content of the particulate oxygen absorber composition dispersed in the oxygen-absorbing resin layer is preferably 0.2% by weight or less, more preferably 0.1% by weight or less. The average particle size of the granular oxygen absorber composition is preferably 100 μm or less, more preferably 80 μm or less.

The content of the oxygen-absorbing composition in the oxygen-absorbing resin composition constituting the oxygen-absorbing resin layer is 10 to 7
0% by weight is preferable, and 10 to 50% by weight is more preferable. When the content of the oxygen scavenger composition is less than 10% by weight, the oxygen absorption performance is reduced, and 70% by weight.
If the amount is larger, the workability deteriorates. The layer thickness of the oxygen-absorbing resin layer is preferably 200 μm or less, more preferably 100 μm or less.

In the oxygen-absorbing resin layer, for example, pigments such as titanium oxide and carbon black, inorganic fillers such as calcium carbonate, clay and mica, silane and titanate dispersants, polyacrylic acid compounds, A water absorbing agent such as calcium, an adsorbent such as activated carbon, an antioxidant, and the like can be added.

The gas barrier layer has a role of blocking oxygen entering from the outside, and has an oxygen permeability of 10 at 25 ° C.
0 cc / m ² · atm · day or less, preferably 50 cc / m ² · atm · day
c / m ² · atm · day or less is more preferable. If the oxygen permeability is larger than 100 cc / m ² · atm · day, the amount of oxygen permeating the gas barrier layer is increased, and the preservability of stored items is undesirably reduced.

As a material constituting the gas barrier layer, a conventionally known gas barrier material, for example, a gas barrier resin such as an ethylene-vinyl alcohol copolymer, polyvinyl chloride, polyvinylidene chloride, or a polyamide resin, or a silica-deposited film, A vapor-deposited film such as an aluminum-deposited film and a metal foil such as an aluminum foil are used. Further, the gas barrier layer may have a multilayer structure in which a protective layer made of polyester such as polyethylene terephthalate, polyolefin such as polypropylene, or polyamide resin such as nylon 6 is provided, and for covering the oxygen-absorbing resin layer. , For example, titanium oxide or carbon black.

The thickness of the gas barrier layer is preferably 5 to 60 μm irrespective of the presence or absence of the protective layer. If the thickness is less than 5 μm, the gas barrier properties may be reduced. Also,
If the thickness is more than 60 μm, there is a problem in cost.

The deoxidizing multilayer film of the present invention can be laminated using a known laminating method such as various laminations and coextrusion, and further layers other than these layers may be added as necessary. They can be combined and laminated for the purpose of maintaining strength, bonding, and smoothing the surface.

The deoxidizing multilayer film of the present invention can be used as a bag-shaped container or a top film of a container with a separating layer as an inner surface by a known method. In this packaging container, for example, articles such as high-moisture foods, beverages, and pharmaceuticals, specifically, high-moisture foods include prepared foods such as cooked rice, boiled foods, fried foods, and sweets such as Japanese sweets such as yokan and cakes. Processed meat and meat products such as sausages, hams, etc., juices such as orange juice as beverages, alcoholic beverages such as sake and whiskey, and pharmaceuticals such as infusion bags. The body is obtained. In this package, the internal oxygen is promptly removed, so that oxidized corrosion or the like of stored items is prevented, and good quality can be maintained even after long-term storage.

[0034]

The present invention will be described in detail with reference to the following examples. First, the materials used in the present invention and the method for measuring the oxygen permeability of the isolation layer and the oxygen permeability coefficient of the thermoplastic resin constituting the oxygen-absorbing resin layer will be described below. Further, the present invention is not limited to the following embodiments. (Materials used) 1) Metallocene polyethylene: Dow Chemical, trade name Affinity PT1450 2) LDPE: Mitsui Chemicals, trade name Mirason 18SP 3) LLDPE: Mitsui Chemicals, trade name Ultzex 1
5100C 4) LLDPE film: TUX-H, manufactured by Tocelo
Z (Measurement method) 1) Oxygen permeability measurement: bag made of a thermoplastic resin film having the same configuration and thickness as the isolation layer (100 mm × 2 on one side)
00 mm), nitrogen gas having an oxygen concentration of 0.1% or less
After 50 cc was sealed and left in a room kept at 25 ° C. and 50% RH for 6 hours, the oxygen concentration in the bag was examined by gas chromatography, and the oxygen permeability was calculated. 2) Oxygen transmission coefficient measurement: a bag (100 mm × 200 m on one side) made of a 100 μm thick thermoplastic resin single-layer film having the same composition as the thermoplastic resin constituting the oxygen-absorbing resin layer
m), 250 c of nitrogen gas having an oxygen concentration of 0.1% or less.
c and left in a room maintained at an atmosphere of 25 ° C. and 50% RH for 6 hours, and then the oxygen concentration in the bag was examined by gas chromatography to calculate the oxygen permeation coefficient.

Example 1 100 kg of reduced iron powder having an average particle diameter of 30 μm was put into a vacuum mixing dryer equipped with a heating jacket, and 5 kg of a 50% by weight aqueous solution of calcium chloride was sprayed while heating at 140 ° C. under a reduced pressure of 10 mmHg. After drying, an oxygen scavenger composition was obtained.

Next, using a 45 mmφ co-rotating twin-screw extruder equipped with a vent and an extruder comprising a quantitative feeder, the mixture was kneaded at a weight ratio of LDPE: oxygen scavenger composition = 60:40 and extruded from a strand die. After, air cooling,
Deoxygenated resin composition 1 was obtained through pelletization. In addition,
The oxygen permeation coefficient of the LDPE constituting the deoxidizing resin composition 1 was 180 cc · mm / m ² · atm · day.

Next, an oxygen-absorbing resin layer made of the oxygen-absorbing resin composition 1 was extruded and laminated on the LDPE side of a multilayer film composed of polyethylene terephthalate (hereinafter, PET) / aluminum foil / LDPE using a tandem extrusion laminator. And the weight ratio of metallocene polyethylene: titanium oxide = 9 on the oxygen-absorbing resin layer side.
An isolation layer made of a mixed resin of 0:10 was extruded and laminated, and PET (12 μm) / aluminum foil (9 μm) / L
DPE (20 μm) / oxygen absorbing resin layer (50 μm) /
An oxygen-absorbing multilayer film 1 having a configuration of an isolation layer (70 μm) was obtained. () Shows the thickness of each layer. The oxygen permeability of the isolation layer was 6,200 cc / m ² · atm · day.

Next, a three-sided sealed bag (inner size: 290 mm long × 200 mm wide) made of the deoxidized multilayer film 1 was prepared, and 200 g of square cut rice cake was filled, and the air volume was about 100 cc.
After sealing by heat sealing so as to obtain a package, the package was left in a room kept at 25 ° C.
The oxygen concentration in the bag on the day and the fourth day was measured by gas chromatography, and one month after the start of storage, the bag was opened to observe the odor and the state of the cut rice cake in the bag. The content storage performance of the film was investigated. Table 1 shows the results.

Example 2 As the oxygen-absorbing resin layer, an oxygen-absorbing resin composition 2 having a weight ratio of metallocene polyethylene: oxygen-absorbing composition = 60: 40 was used, and as an isolating layer, LLDPE: titanium oxide = 90: 10. PET (12 μm) / aluminum foil (9 μm) / LDPE (20 μm) / oxygen-absorbing resin layer (50 μm) / isolating layer (70 μm) in the same manner as in Example 1 except that a mixed resin having a weight ratio of ) Was obtained. The oxygen permeability coefficient of the metallocene polyethylene constituting the deoxidizing resin composition 2 was 450 cc · mm / m ² · atm · day,
The oxygen permeability of the isolation layer is 2100 cc / m ² · atm · d
It was ay. Next, a three-sided sealed bag made of the oxygen-reducing multilayer film 2 was produced, and the same storage test as in Example 1 was performed. Table 1 shows the results.

Example 3 A PET (12 μm) was prepared in the same manner as in Example 1 except that the oxygen-absorbing resin composition 2 was used as the oxygen-absorbing resin layer.
m) / aluminum foil (9 μm) / LDPE (20 μm) / oxygen-absorbing resin layer (50 μm) / separation layer (70 μm). Next, a three-sided seal bag made of the oxygen-reducing multilayer film 3 was produced, and the same storage test as in Example 1 was performed. Table 1 shows the results.

Example 4 The separating layer was made of a mixed resin having a weight ratio of metallocene polyethylene: LLDPE: titanium oxide = 10: 80: 10,
PET (12 μm) / aluminum foil (9 μm) / LD in the same manner as in Example 1 except that the thickness was set to 50 μm.
An oxygen-absorbing multilayer film 4 having a configuration of PE (20 μm) / oxygen-absorbing resin layer (50 μm) / isolation layer (50 μm) was obtained. The oxygen permeability of the isolation layer was 3700 cc /
m ² · atm · day. Next, a three-sided sealed bag made of the oxygen-reducing multilayer film 4 was produced, and the same storage test as in Example 1 was performed. Table 1 shows the results.

Example 5 Metallocene polyethylene: LD as an oxygen-absorbing resin layer
The oxygen-absorbing composition 3 having a weight ratio of PE: oxygen-absorbing composition = 20: 40: 40 was used, and the thickness of the isolation layer was 5
PET film was made in the same manner as in Example 2 except that the thickness was changed to 0 μm.
(12 μm) / Aluminum foil (9 μm) / LDPE (20 μm)
m) / oxygen-absorbing resin layer (50 μm) / isolation layer (50 μm)
A deoxidized multilayer film 5 having the configuration of m) was obtained. The oxygen permeability coefficient of the mixed resin constituting the oxygen-absorbing resin layer was 270 cc · mm / m ² · atm · day,
The oxygen permeability of the isolation layer is 3000 cc / m ² · atm · d
It was ay. Next, a three-sided seal bag made of the oxygen-reducing multilayer film 5 was produced, and the same storage test as in Example 1 was performed. Table 1 shows the results.

Example 6 The procedure of Example 4 was repeated, except that the oxygen-absorbing composition was used as the oxygen-absorbing resin layer, and PET (12 μm) /
An oxygen-absorbing multilayer film 6 having a configuration of aluminum foil (9 μm) / LDPE (20 μm) / oxygen-absorbing resin layer (50 μm) / isolation layer (50 μm) was obtained. Next, a three-sided seal bag made of the oxygen-reducing multilayer film 6 was produced, and the same storage test as in Example 1 was performed. Table 1 shows the results.

Example 7 Using an extrusion laminator, a multilayer film composed of PET (12 μm) / aluminum foil (9 μm) / LDPE (20 μm), metallocene polyethylene: titanium oxide = 9
Sand-laminated oxygen-absorbing resin composition 1 between white films (50 μm) having a weight ratio of 0:10,
PET (12μm) / Aluminum foil (9μm) / LDPE
An oxygen-absorbing multilayer film 7 having a configuration of (20 μm) / oxygen-absorbing resin layer (30 μm) / isolation layer (50 μm) was obtained. The oxygen permeability of the isolation layer was 8800 cc / m ^2.
・ Atm ・ day. Next, a three-sided seal bag made of the oxygen-reducing multilayer film 7 was produced, and the same storage test as in Example 1 was performed. Table 1 shows the results.

Example 8 Using a tandem type extrusion laminator, an oxygen-absorbing resin layer made of the oxygen-absorbing resin composition 2 was extruded and laminated on a film (30 μm) made of LLDPE.
Furthermore, metallocene polyethylene: titanium oxide = 90: 1
Extruding and laminating an isolating layer having a weight ratio of 0,
LLDPE (30 μm) / oxygen absorbing resin layer (50 μm)
m) / Multilayer film having a configuration of an isolation layer (50 μm) was obtained. Further, the multilayer film and PET (12 μm) / aluminum foil (9 μm) are laminated via LDPE, and PET (12 μm) / aluminum foil (9 μm) / LD
An oxygen-absorbing multilayer film 8 having a configuration of PE (20 μm) / LLDPE (30 μm) / oxygen-absorbing resin layer (50 μm) / isolation layer (50 μm) was obtained. Next, a three-sided sealed bag made of the oxygen-reducing multilayer film 8 was produced, and the same storage test as in Example 1 was performed. Table 1 shows the results.

Example 9 Using a tandem extrusion laminator, a mixed resin having a weight ratio of metallocene polyethylene: titanium oxide = 90: 10 was extruded and laminated on an LLDPE film (30 μm). Extrusion-laminated oxygen-absorbing resin layer consisting of
A multilayer film composed of PE (30 μm) / white resin layer (20 μm) / oxygen absorbing resin layer (50 μm) was obtained. Further, the above-mentioned multilayer film and PET are made through LDPE.
(12 μm) / Laminate aluminum foil (9 μm)
ET (12 μm) / aluminum foil (9 μm) / LDPE (2
0 μm) / oxygen-absorbing resin layer (50 μm) / white resin layer (20 μm) / LLDPE layer (30 μm). The oxygen permeability of the white resin layer (20 μm) / LLDPE (30 μm) serving as the isolation layer was 4000 cc / m ² · atm · day. Next, a three-side sealed bag made of the deoxidized multilayer film 9 was produced, and the same storage test as in Example 1 was performed. Table 1 shows the results.

Comparative Example 1 PET (12 μm) was prepared in the same manner as in Example 5 except that the deoxidizing resin composition 1 was used as the oxygen absorbing resin layer.
/ Aluminum foil (9 μm) / LDPE (20 μm) / oxygen-absorbing resin layer (50 μm) / separation layer (50 μm). Next, a three-sided seal bag made of the deoxidized multilayer film 10 is produced,
The same storage test as in Example 1 was performed. Table 1 shows the results.

Comparative Example 2 PET (12 μm) / aluminum foil (9 μm) in the same manner as in Example 1 except that no oxygen-absorbing resin layer was provided.
An oxygen-absorbing multilayer film 11 having a configuration of / LDPE (20 μm) / isolation layer (70 μm) was obtained. Next, a three-side seal bag made of the deoxidized multilayer film 11 was produced,
The same storage test as in Example 1 was performed. Table 1 shows the results.

[0049]

[Table 1] Preservability of contents ○: There was no abnormality in appearance, and the flavor was well maintained. ×: Mold was generated partially (Comparative Example 1), and mold was generated and had an unpleasant odor (Comparative Example 2)

As is apparent from these Examples and Comparative Examples, in Examples 1 to 9 in which a metallocene polyethylene was used for one or both of the isolation layer and the oxygen-absorbing resin layer of the oxygen-absorbing multilayer film. The practical oxygen absorption rate was demonstrated, the oxygen concentration in the packaging bag reached 0.1% or less within 4 days in all cases, and the preservation of the cut rice cake, which was stored, was confirmed to be excellent. Was done. On the other hand, as in Comparative Example 1, in the case of a deoxidized multilayer film not using metallocene polyethylene, the oxygen concentration in the bag did not reach 0.1% or less even after 4 days from the start of the test. , Some molds occurred. Further, in the case of the oxygen-absorbing multilayer film having no oxygen-absorbing resin layer as in Comparative Example 2, mold was generated, and the preservability of the contents was inferior.

[0051]

The oxygen-absorbing multilayer film of the present invention has excellent oxygen-absorbing performance over conventional oxygen-absorbing multilayer films. Therefore, the oxygen-absorbing multilayer film of the present invention has been applied to various packaging materials that have been used up to now, since a function of absorbing oxygen in the packaging bag at a practical speed has been imparted. It can be used for storing various goods.

Claims (5)

[Claims] 1. A gas barrier layer, at least an oxygen-absorbing resin layer made of a deoxidizing resin composition in which an oxygen-absorbing composition is dispersed in a thermoplastic resin, and an isolation layer made of a thermoplastic resin laminated in this order. In the oxygen-absorbing multilayer film composed of three layers, one or both of the oxygen-absorbing resin layer and the thermoplastic resin constituting the isolation layer are made of a metallocene-catalyzed polyethylene alone or a mixed resin with another thermoplastic resin. A deoxidizing multilayer film characterized by comprising: 2. The oxygen-absorbing multilayer film according to claim 1, wherein the content of the metallocene-catalyzed polyethylene in the thermoplastic resin constituting the oxygen-absorbing resin layer and / or the isolating layer is 10 to 100% by weight. 3. The oxygen permeation coefficient at 25 ° C. of polyethylene alone or a mixed resin with another thermoplastic resin by the metallocene catalyst constituting the oxygen-absorbing resin layer is 250 cc · m.
The deoxidizing multilayer film according to claim 1, which has a m / m ² · atm · day or more. 4. A simple metallocene catalyst for polyethylene.
Isolation composed of resin mixed with German or other thermoplastics
The oxygen permeability of the layer at 25 ° C. is 3500 cc / m ^Two・ At
2. The deoxidizing multilayer film according to claim 1, which has a m.day or more.
Lum. 5. The packaging container according to claim 1, wherein at least a part of the packaging container is provided.
A packaging container comprising the oxygen-absorbing multilayer film as described above, wherein the isolation layer is inside and the oxygen in the packaging container is absorbed.