JP2008006635A - Oxygen-absorbent multilayer film superior in tearability and oxygen absorbing packaging container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxygen-absorbent multilayer film which is superior in strength as a packaging material, heat-sealability, appearance, the easiness in unsealing, and the preservation of contents, and an oxygen-absorbent multilayer container. <P>SOLUTION: In a deoxidant film, a gas-barrier layer comprising at least a gas-barrier substance, an oxygen absorbing resin layer comprising an oxygen absorbing resin composition in which an iron-type oxygen absorbing agent is incorporated into a polyolefin, and a heat seal resin layer are arranged from the outer surface side. In the oxygen-absorbent multilayer film superior in tearability, the tear strength in the TD direction (film width direction) of the heat seal resin layer is 5 N or below. The oxygen-absorbent multilayer packaging container using the multilayer film is also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a multilayer film having an oxygen absorption function, a packaging container using the same, and a manufacturing method. Specifically, the present invention has an excellent cutting property in which a heat seal resin layer having a tear strength in the TD direction (film width direction) of 5 N or less is provided on the heat seal resin layer, and packaging of food, medicine, etc. The present invention relates to an oxygen-absorbing multilayer film that stores contents as a material.

  In recent years, as one of the deoxygenation packaging technologies, a container is made up of a multilayer material in which an oxygen absorbing layer composed of an oxygen absorbing resin composition in which a deoxidizing agent is blended with a thermoplastic resin, and the gas barrier property of the container is improved. At the same time, development of packaging containers in which the container itself is provided with an oxygen absorbing function has been underway. For example, an oxygen-absorbing multilayer film is a thermoplastic in which an oxygen absorbent is dispersed between a conventional gas-barrier multilayer film in which a heat seal layer and a gas barrier layer are laminated, and optionally through an intermediate layer made of a thermoplastic resin. It is used as a resin layer with an oxygen absorption layer added to the outside to prevent oxygen permeation, and to absorb oxygen in the container. It is manufactured using a method (Patent Document 1).

However, the oxygen-absorbing multilayer film composed of a gas barrier layer, an oxygen-absorbing layer, and a heat seal layer may increase the thickness of the oxygen-absorbing multilayer film by the amount of the oxygen-absorbing layer compared to the conventional barrier film described above. There is a problem that the tearability of the multilayer film is inevitable.
It can be considered that the thickness of the oxygen-absorbing laminate is reduced and the tearability is improved by reducing the thickness of the oxygen-absorbing layer and / or the heat seal layer. However, when reducing the thickness of the oxygen-absorbing layer, not only the strength of the layer is lowered, but also the oxygen-absorbing function is lowered, and the storage stability of food, medicine, etc. in a packaging container made of an oxygen-absorbing multilayer film is reduced. It is difficult to reduce the thickness. When reducing the thickness of the heat seal layer, the sealing performance of the packaging container made of an oxygen-absorbing multilayer film is reduced, and the packaging container filled and sealed with the contents may be broken at the sealing site during heat treatment or transportation. It is difficult to put it to practical use.

Japanese Patent No. 3019153

  The present invention relates to an oxygen-absorbing multilayer film comprising a gas barrier layer, an oxygen-absorbing layer, and a heat-sealing layer, which has excellent oxygen-absorbing performance and has improved tearability while maintaining the sealing strength of the packaging container. An object is to provide an absorbent multilayer film and an oxygen-absorbing packaging container using the same.

  In light of the above-mentioned problems of the prior art, the present inventors have made extensive studies, and as a result, the heat seal layer used in the oxygen-absorbing multilayer film is a specific heat-sealable film. The present inventors have found that the above-mentioned problems of the conductive multilayer body can be solved, and have solved the present invention.

  The present invention relates to a deoxygenating film comprising, from the outer surface side, a gas barrier layer comprising at least a gas barrier substance, an oxygen absorbing resin layer comprising an oxygen-absorbing resin composition in which an iron-based oxygen absorbent is blended with polyolefin, and a heat seal resin layer. The oxygen-absorbing multilayer film having excellent tearability, wherein the tear strength in the TD direction (film width direction) of the heat seal resin layer is 5 N or less. The tear strength in the TD direction of the heat seal resin layer is measured according to JIS K7128-2 method.

In the present invention, the polyolefin constituting the oxygen-absorbing resin layer is a polyethylene resin, and the oxygen-absorbing multilayer film in which the gas barrier layer is an aluminum foil.
The oxygen-absorbing multilayer film of the present invention is an oxygen-absorbing packaging container that is a part or all of the packaging container, and the article is stored in the oxygen-absorbing packaging container after being heat-treated.

  The oxygen-absorbing multilayer film of the present invention is not only excellent in preservability of stored articles in a packaging container but also has excellent tearability as a packaging material having an oxygen-absorbing function. It has good openability and is useful for long-term storage applications such as food.

Hereinafter, the oxygen-absorbing multilayer film of the present invention and a packaging container using the same will be described.
The heat-sealing resin layer constituting the oxygen-absorbing multilayer film of the present invention is a portion that forms a packaging container and serves as a sealant for sealing stored articles when the oxygen-absorbing multilayer film is used as a packaging container. It has a role as an isolation layer that separates the stored article from the oxygen absorbing layer, and a role as an oxygen permeable layer that allows oxygen in the packaging container to permeate and be quickly absorbed by the oxygen absorbent in the oxygen absorbing layer.

  For the heat seal resin layer constituting the oxygen-absorbing multilayer film of the present invention, a sealant film having a tear strength in the TD direction (film width direction) of 5 N or less is preferably used. More preferably, a sealant film having a tear strength of 3N or less in the TD direction (film width direction) is used. Thereby, not only the function as an isolation layer with respect to the stored article but also good tearability as an oxygen-absorbing multilayer film can be obtained.

  Add color pigments such as titanium oxide, additives such as antioxidants, slip agents, antistatic agents, stabilizers, fillers such as calcium carbonate, clay, mica, silica, and deodorizers to the heat seal resin layer. You may do it. The heat seal resin layer may have a multilayer structure formed by extrusion lamination or coextrusion lamination.

  The film thickness of the heat seal resin layer constituting the oxygen-absorbing multilayer film is preferably 30 to 100 μm, and more preferably 40 to 70 μm. When the thickness of the heat seal layer is less than 30 μm, the oxygen absorbent in the oxygen absorption layer is exposed on the surface or the heat seal strength is lowered, which is not preferable. Also, if the thickness of the heat seal layer is greater than 100 μm, lamination becomes difficult, tearing properties are deteriorated, oxygen permeability is lowered and the oxygen absorption rate of the film is lowered, and the cost is further increased. Therefore, it is not preferable.

  The oxygen-absorbing resin layer constituting the oxygen-absorbing multilayer film is obtained by dispersing an oxygen absorbent in a thermoplastic resin. The oxygen-absorbing resin layer has a role of absorbing oxygen dissolved in the container or in the stored article, and also has a role of preventing a small amount of oxygen entering from the outside of the gas barrier layer to prevent oxygen permeation into the container.

Polyolefin is used for the resin that forms the oxygen-absorbing resin layer. Specifically, low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, and metallocene polyethylene (or copolymer) are used. Polypropylenes such as polyethylene, polypropylene, propylene-ethylene random copolymer, propylene-ethylene block copolymer and metallocene polypropylene (or copolymer), polyolefins (or copolymer) such as polymethylpentene, ethylene- Examples thereof include elastomers such as propylene rubber, ethylene vinyl acetate copolymers, and mixtures thereof.
A metallocene polyethylene is a polyethylene produced by a gas phase method or a solution method using a metallocene catalyst that is a homogeneous compound soluble in a solution and having a structure in which a transition metal catalyst is sandwiched between unsaturated cyclic compounds. . Metallocene polyethylene is relatively monodisperse in molecular weight distribution and has few high molecular weight and low molecular weight components, so it has superior impact resistance and low odor compared to polyethylene using conventional Ziegler catalysts, and oxygen permeation. Therefore, it is preferable as a material constituting the oxygen absorption layer.
The resin that forms the oxygen-absorbing resin layer can be made of the same type of resin as the heat-seal resin layer, or a different type of resin that is compatible with each other and can be heat-sealed, thereby providing high interlayer bonding strength. It is done.

As the iron-based oxygen absorbent dispersed in the oxygen absorption layer, a mixture of iron powder and metal halide is used.
As the iron powder as the main agent, it can be used without any particular limitation on the purity so long as it can cause an oxygen absorption reaction. For example, a part of the surface may already be oxidized and contains other metals. It may be what you do. The iron powder is preferably granular, and for example, iron powder such as reduced iron powder, sprayed iron powder, and electrolytic iron powder, pulverized products of various iron such as cast iron and steel, and ground products are used. The average particle size is preferably in the range of 1 to 100 μm in consideration of handling properties, reducing the film thickness of the oxygen absorbing layer, and preventing asperities of the oxygen absorbent appearing in the film appearance as much as possible. In particular, the range of 1 to 80 μm is preferable.

  As the metal halide which is an auxiliary agent for the iron-based oxygen absorber, for example, alkali metal or alkaline earth metal chloride, bromide or iodide is used, and lithium, sodium, potassium, magnesium, calcium or barium chloride is used. Products, bromides or iodides are preferably used. The compounding amount of the metal halide is preferably 0.1 to 20 parts by weight, particularly preferably 0.1 to 5 parts by weight per 100 parts by weight of the iron powder.

  It is preferable that the metal halide is mixed and added in advance so as not to adhere to the iron powder and easily separate. For example, a method of mixing a metal halide and iron powder using a ball mill, a speed mill, etc., a method of embedding a metal halide in the uneven portion of the iron powder surface, a method of attaching a metal halide to the iron powder surface using a binder A method of adhering a metal halide to the surface of the iron powder by drying after mixing the aqueous metal halide solution and the iron powder can be employed. A preferable oxygen absorbent is an iron powder-based composition containing iron powder and a metal halide, and particularly preferably a metal halide-coated iron powder-based composition in which a metal halide is attached to the iron powder.

  The blending amount of the oxygen absorbent in the oxygen absorbing layer is preferably in the range of 10 to 70% by weight, and more preferably in the range of 10 to 60% by weight. When the blending amount of the oxygen absorbent is lower than 10% by weight, the oxygen absorbing ability is insufficient and not preferable, and when it is higher than 60% by weight, it is difficult to form an oxygen absorbing layer, which is not preferable.

  The film thickness of the oxygen absorbing layer is preferably in the range of 10 to 100 μm, particularly preferably in the range of 20 to 80 μm. If the film thickness of the oxygen absorbing layer is thinner than 10 μm, film formation becomes difficult, or the amount of oxygen absorbent per unit area of the film decreases, and sufficient oxygen absorbing performance cannot be obtained. On the other hand, if the thickness is larger than 100 μm, the total film thickness is increased, which may cause inconvenience in handling properties, cutting performance may be deteriorated, and cost may be problematic.

  In addition, the oxygen absorbing layer of the present invention may contain various additives such as coloring pigments such as titanium oxide, antioxidants, slip agents, antistatic agents, stabilizers, clay, mica, silica, calcium carbonate, if necessary. In addition, fillers such as calcium sulfate and barium sulfate, deodorizers, adsorbents such as activated carbon and zeolite may be added.

  The gas barrier layer of the oxygen-absorbing multilayer film is a layer that blocks oxygen entering from the outside of the container, and a gas barrier material having low oxygen gas permeability is used. For example, a metal foil such as aluminum foil, or a nylon MXD6, a mixture of nylon MXD6 and nylon 6, a gas barrier thermoplastic resin such as ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol (PVA) or PVDC, silica or A vapor-deposited film such as an inorganic oxide obtained by vapor-depositing alumina or the like on a film of polyester or polyamide is used. Aluminum foil is particularly preferably used because of its gas barrier properties.

  An intermediate layer made of a thermoplastic resin may be provided between the oxygen-absorbing multilayer film and the gas barrier layer of the oxygen-absorbing multilayer film as long as the effects of the present invention are not impaired. As the thermoplastic resin of the intermediate layer, low density polyethylene, medium density polyethylene, high density polyethylene, polyamide such as nylon 6 or nylon 6,6, polyethylene terephthalate, or the like can be used. The thickness of the intermediate resin layer is preferably 10 μm or more and less than 30 μm.

  It is preferable to laminate an outer layer made of an impact-resistant thermoplastic resin on the surface of the multilayer film outside the gas barrier layer constituting the oxygen-absorbing multilayer film. Preferred impact-resistant thermoplastic resins include polyesters such as polyethylene terephthalate, polyamides such as nylon 6 and nylon 6,6, and polypropylene. A printing layer can be provided between the gas barrier layer and the outer layer.

  Each layer constituting the oxygen-absorbing multilayer film can be bonded using a urethane-based or epoxy-based adhesive or a polyolefin-based hot melt agent. Moreover, you may join by the heat sealing | fusion method, without using an adhesive agent.

  By using the oxygen-absorbing multilayer film of the present invention described above for the whole packaging container or a part of the packaging container made of a gas barrier material, oxygen in the container in addition to oxygen that slightly enters from the outside of the container. Can be absorbed to prevent alteration of the contents to be stored due to oxygen. The oxygen-absorbing multilayer film is molded and used in packaging containers such as three-side sealed flat bags, standing pouches, gusset packaging bags, pillow packaging bags, etc., so that the packaging container has a deoxygenating function and has excellent openability. It can be a packaging container. In addition, when used as a member such as a container lid or top seal, the trimability (punching) of the lid or the like is improved due to the effect of improving the tearability of the oxygen-absorbing multilayer film of the present invention, and the packaging container is used. Deoxygenation function is added.

  The oxygen-absorbing packaging container made of the oxygen-absorbing multilayer film of the present invention accommodates food, pharmaceuticals and the like without limitation. For example, liquid drinks such as juice, liquor, coffee, tea, jelly drink, health drink, seasoning liquid, sauce, soy sauce, dressing, soba soup, ramen soup, liquid dashi, mayonnaise, miso, grated spices, cream Paste foods such as chocolate paste, jam, vegetable paste, liquid processed foods such as liquid soup, boiled food, pickles, stew, curry, cut fruit and fruit syrup pickled in mandarin, pine, peach, mango, etc. Aloe, pudding, jelly, processed food with pulp, desserts such as sheep crab, rice cake, black honey, white honey, raw noodles such as buckwheat, udon, ramen, boiled noodles, polished rice, conditioned rice, unwashed rice High-moisture foods such as rice and processed rice products such as cooked rice, gomoku rice, and rice bran, powdered soups, and powdered seasonings such as dashi nomoto Various materials such as industrial materials, solid and solution chemicals such as agricultural chemicals and insecticides, liquid and paste pharmaceuticals, cosmetic emulsions, lotions, cosmetic creams, hair conditioners, hair dyes, shampoos, soaps, detergents, etc. Can be stored. Above all, for foods that discolor due to oxygen, specifically for fruits such as pickled fruit syrup, confectionery such as mutton, strawberries, honey, seasoning liquid, sauce, soy sauce, soba soup, ramen soup, etc. It can be used suitably. Oxygen does not enter from the outside of the container, and oxygen inside the container is absorbed by the oxygen scavenger composition, so that oxidative corrosion or the like of the article is prevented and good quality can be maintained for a long time.

  Moreover, you may heat-process the sealed container of this invention. Examples of the heat treatment include boil treatment at 80 ° C. to 100 ° C., boiling treatment, retort treatment such as semi-retort, retort, and high retort at 100 ° C. to 135 ° C. In particular, when the sealed container of the present invention is used, heat treatment at 80 ° C. or higher can be suitably performed, and foods and pharmaceuticals can be stored for a long period of time.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

Production Example 1
1000 kg of iron powder with an average particle size of 30 μm is put into a vacuum dryer with a heating jacket, sprayed with 50 kg of 50% calcium chloride aqueous solution while mixing at 140 ° C. under reduced pressure of 10 mmHg, and dried at 140 ° C. for 1 hour. An oxygen scavenger with calcium chloride attached to the iron powder was obtained. The oxygen absorber having an average particle size of 30 μm was obtained by sieving the oxygen scavenger.
Next, using a twin screw extruder with a vent, while extruding a linear low density polyethylene (manufactured by Nippon Polyethylene Co., Ltd., trade name Kernel KC580S, hereinafter referred to as LLDPE), the iron-based iron obtained above by side feed is used. Oxygen absorbent is supplied so that LLDPE: oxygen absorbent: calcium oxide = 59: 40: 1 (weight ratio), kneaded, extruded from a strand die, cooled, pelletized by a pelletizer, and oxygen absorbed Resin composition A was obtained.

Example 1
LLDPE film (heat seal layer, TUD34 manufactured by Tosero Co., Ltd., thickness 40 μm, tear strength in the TD direction) using an extrusion laminator device consisting of a single screw extruder, T die, cooling roll and slitter and winder On the opposite side of the surface subjected to the corona discharge treatment of 3.8N), the oxygen-absorbing resin composition A produced in Production Example 1 was extruded and laminated with a thickness of 30 μm, and a film 1 composed of a heat-sealing layer 40 μm / oxygen-absorbing layer 30 μm was obtained. Created.

  A 9 μm thick aluminum foil (gas barrier layer) is dry-laminated on the oxygen absorbing layer side of the obtained film 1, and a 15 μm thick stretched nylon 6 film and a 12 μm thick polyethylene terephthalate film are sequentially applied to the aluminum foil. Dry lamination was performed to obtain an oxygen-absorbing multilayer film composed of outer layer (PET) 12 / adhesive / outer layer (nylon) 15 / adhesive / gas barrier layer (aluminum foil) 9 / oxygen absorbing layer 30 / heat seal layer 40. The tear strength of the obtained multilayer film in the TD direction was 3.9N.

Using the obtained oxygen-absorbing multilayer film, a 130 mm × 100 mm three-sided seal bag (heat seal width 10 mm) was prepared, filled with mango paste and sealed to prepare an oxygen-absorbing packaging bag. Further, a notch (I notch) having a length of 5 mm was made at the end of the heat seal portion of the packaging bag so as to be parallel to the TD direction of the multilayer film. The produced packaging bag was sterilized by heating at 90 ° C. for 30 minutes. When the appearance of the bag was observed after the treatment, there was no abnormality such as leakage in the heat seal part, and there was no deformation of the bag. Furthermore, when the packaging bag was torn open from the cut portion, it could be easily opened. Moreover, the packaging bag after heat processing was preserve | saved under 30 degreeC and 80% RH, and the oxygen concentration in a bag and the external appearance of a mango paste of a preservation | save 1 month were investigated. The oxygen concentration in the bag was reduced to 0.1% or less, the mango paste was not discolored, and the flavor was good.

Example 2
The outer layer (PET) 12 / adhesive / outer layer (in the same manner as in Example 1 except that LL-MTNST (thickness: 40 μm, tear strength in the TD direction: 2.7 N) was used for the LLDPE film. Nylon) 15 / adhesive / gas barrier layer (aluminum foil) 9 / oxygen absorbing layer 30 / heat seal layer 40 was obtained. The tear strength of the obtained multilayer film in the TD direction was 3.8N.

Using the obtained oxygen-absorbing multilayer film, a 130 mm × 100 mm three-sided seal bag (heat seal width 10 mm) was prepared, filled with mango paste and sealed to prepare an oxygen-absorbing packaging bag. Further, a notch (I notch) having a length of 5 mm was made at the end of the heat seal portion of the packaging bag so as to be parallel to the TD direction of the multilayer film. The produced packaging bag was sterilized by heating at 90 ° C. for 30 minutes. When the appearance of the bag was observed after the treatment, there was no abnormality such as leakage in the heat seal part, and there was no deformation of the bag. Furthermore, when the packaging bag was torn open from the cut portion, it could be easily opened. Moreover, the packaging bag after heat processing was preserve | saved under 30 degreeC and 80% RH, and the oxygen concentration in a bag and the external appearance of a mango paste of a preservation | save 1 month were investigated. The oxygen concentration in the bag was reduced to 0.1% or less, the mango paste was not discolored, and the flavor was good.

Example 3
The outer layer (PET) 12 / adhesive / outer layer (in the same manner as in Example 1, except that L-147 (thickness: 40 μm, tear strength in the TD direction: 4.9 N) was used for the LLDPE film. Nylon) 15 / adhesive / gas barrier layer (aluminum foil) 9 / oxygen absorbing layer 30 / heat seal layer 40 was obtained. The tear strength of the obtained multilayer film in the TD direction was 4.2N.

Using the obtained oxygen-absorbing multilayer film, a 130 mm × 100 mm three-side sealed bag (heat seal width 10 mm) was prepared, and sealed with a bag to prepare an oxygen-absorbing packaging bag. Further, a notch (I notch) having a length of 5 mm was made at the end of the heat seal portion of the packaging bag so as to be parallel to the TD direction of the multilayer film. The produced packaging bag was heat sterilized at 95 ° C. for 30 minutes. When the appearance of the bag was observed after the treatment, there was no abnormality such as leakage in the heat seal part, and there was no deformation of the bag. Furthermore, when the packaging bag was torn open from the cut portion, it could be easily opened. Moreover, the packaging bag after heat processing was preserve | saved under 30 degreeC and 80% RH, and the oxygen concentration in a bag of storage 1 month and the external appearance of the soot were investigated. The oxygen concentration in the bag was reduced to 0.1% or less, and there was no discoloration of the candy and the flavor was good.

Comparative Example 1
The outer layer (PET) 12 / adhesive / outer layer (nylon) 15 was the same as in Example 1 except that Tosero FCS (thickness 40 μm, tear strength 5.3D in the TD direction) was used for the LLDPE film. An oxygen-absorbing multilayer film consisting of: / adhesive / gas barrier layer (aluminum foil) 9 / oxygen absorption layer 30 / heat seal layer 40 was obtained. The tear strength of the obtained multilayer film in the TD direction was 7.2N.

Using the obtained oxygen-absorbing multilayer film, a 130 mm × 100 mm three-sided seal bag (heat seal width 10 mm) was prepared, filled with mango paste and sealed to prepare an oxygen-absorbing packaging bag. Further, a notch (I notch) having a length of 5 mm was made at the end of the heat seal portion of the packaging bag so as to be parallel to the TD direction of the multilayer film. The produced packaging bag was sterilized by heating at 90 ° C. for 30 minutes. When the appearance of the bag was observed after the treatment, there was no abnormality such as leakage in the heat seal part, and there was no deformation of the bag. However, an attempt was made to tear and open the packaging bag from the cut portion, but the tearability of the film was poor and it was difficult to open without spilling the content article. The packaging bag after the heat treatment was stored at 30 ° C. and 80% RH, and the oxygen concentration in the bag and the appearance of the mango paste in the first month of storage were investigated. The oxygen concentration in the bag was reduced to 0.1% or less, the mango paste was not discolored, and the flavor was good.

Comparative Example 2
Outer layer (PET) 12 / adhesive / outer layer (nylon) in the same manner as Example 1 except that L140 (made by Aicero Chemical Co., Ltd., thickness 40 μm, tear strength TD in the TD direction) was used for the LLDPE film. An oxygen-absorbing multilayer film comprising 15 / adhesive / gas barrier layer (aluminum foil) 9 / oxygen absorption layer 30 / heat seal layer 40 was obtained. The tear strength of the obtained multilayer film in the TD direction was 7.0N.

Using the obtained oxygen-absorbing multilayer film, a 130 mm × 100 mm three-side sealed bag (heat seal width 10 mm) was prepared, and sealed with a bag to prepare an oxygen-absorbing packaging bag. Further, a notch (I notch) having a length of 5 mm was made at the end of the heat seal portion of the packaging bag so as to be parallel to the TD direction of the multilayer film. The produced packaging bag was heat sterilized at 95 ° C. for 30 minutes. When the appearance of the bag was observed after the treatment, there was no abnormality such as leakage in the heat seal part, and there was no deformation of the bag. However, an attempt was made to tear and open the packaging bag from the cut portion, but the tearability of the film was poor and it was difficult to open. On the other hand, the packaging bag after the heat treatment was stored at 30 ° C. and 80% RH, and the oxygen concentration in the bag and the appearance of the bag after the first storage were examined. The oxygen concentration in the bag was reduced to 0.1% or less, and there was no discoloration of the candy and the flavor was good.

Comparative Example 3
An aluminum foil (gas barrier layer) with a thickness of 9 μm is dry-laminated on an LLDPE film (L140 made by Aicero Chemical Co., Ltd., thickness 140 μm, tear strength 5.4 N in TD direction), and 15 μm-thick stretched nylon is further formed on the aluminum foil. 6 films and a polyethylene terephthalate film having a thickness of 12 μm are sequentially dry-laminated to form a multilayer consisting of outer layer (PET) 12 / adhesive / outer layer (nylon) 15 / adhesive / gas barrier layer (aluminum foil) 9 / heat seal layer 40. A film was obtained. The tear strength of the obtained multilayer film in the TD direction was 4.4N.

Using the obtained multilayer film, a 130 mm × 100 mm three-side sealed bag (heat seal width 10 mm) was prepared, filled with a bag, and sealed to prepare an oxygen-absorbing packaging bag. Further, a notch (I notch) having a length of 5 mm was made at the end of the heat seal portion of the packaging bag so as to be parallel to the TD direction of the multilayer film. The produced packaging bag was heat sterilized at 95 ° C. for 30 minutes. When the appearance of the bag was observed after the treatment, there was no abnormality such as leakage in the heat seal part, and there was no deformation of the bag. When the packaging bag was torn and opened from the cut portion, it could be opened easily. On the other hand, the packaging bag after the heat treatment was stored at 30 ° C. and 80% RH, and the oxygen concentration in the bag and the appearance of the bag after the first storage were examined. The oxygen concentration in the bag was 19.6%, discoloration was observed in the bag, and the flavor was also lowered.

Example 4
Outer layer (PET) 12 / adhesive / outer layer (nylon) in the same manner as in Example 1 except that L143 film made by Aicero Chemical Co., Ltd., L143, thickness 50μ (TD tear strength 3.8N) was used for the LLDPE film. An oxygen-absorbing multilayer film comprising 15 / adhesive / gas barrier layer (aluminum foil) 9 / oxygen absorption layer 30 / heat seal layer 50 was obtained. The tear strength of the obtained multilayer film in the TD direction was 3.9N.

  Using the obtained oxygen-absorbing multilayer film, a 130 mm × 100 mm three-side sealed bag (heat seal width 10 mm) was prepared, filled with strawberry jam and sealed to prepare an oxygen-absorbing packaging bag. Further, a notch (I notch) having a length of 5 mm was made at the end of the heat seal portion of the packaging bag so as to be parallel to the TD direction of the multilayer film. The produced packaging bag was heat sterilized at 95 ° C. for 60 minutes. When the appearance of the bag was observed after the treatment, there was no abnormality such as leakage in the heat seal part, and there was no deformation of the bag. Furthermore, when the packaging bag was torn open from the cut portion, it could be easily opened. Moreover, the packaging bag after heat processing was preserve | saved under 30 degreeC and 80% RH, and the oxygen concentration in a bag and the external appearance of the preservation | save 1 month were investigated. The oxygen concentration in the bag was reduced to 0.1% or less, the strawberry jam was not discolored, and the flavor was good.

Production Example 2
1000 kg of iron powder with an average particle size of 30 μm is put into a vacuum dryer with a heating jacket, sprayed with 50 kg of 50% calcium chloride aqueous solution while mixing at 140 ° C. under reduced pressure of 10 mmHg, and dried at 140 ° C. for 1 hour. An oxygen scavenger with calcium chloride attached to the iron powder was obtained. The oxygen absorber having an average particle size of 30 μm was obtained by sieving the oxygen scavenger.
Next, linear low-density polyethylene (manufactured by Nippon Polyethylene Co., Ltd., trade name Kernel KC580S, hereinafter referred to as LLDPE) and low-density polyethylene (Tosoh Corp., Petrocene 204, hereinafter referred to as LDPE) are LLDPE: LDPE = 80: 20 After dry blending, an iron-based oxygen absorbent is fed by side feed while extruding a blended resin of LLDPE and LDPE using a vented twin screw extruder, and blend resin: iron-based oxygen absorbent: calcium oxide. = 59: 40: 1 Weight ratio was supplied, kneaded, extruded from the strand die, then cooled and pelletized with a pelletizer to obtain an oxygen-absorbing resin composition B.

Example 5
LLDPE film (heat seal layer, TUD34 manufactured by Tosero Co., Ltd., thickness 40 μm, tear strength in the TD direction) using an extrusion laminator device consisting of a single screw extruder, T die, cooling roll and slitter and winder 3.8N) On the opposite side of the corona discharge-treated surface, the oxygen-absorbing resin composition B produced in Production Example 2 was extruded and laminated with a thickness of 30 μm, and a film 2 consisting of a heat-sealing layer 40 μm / oxygen-absorbing layer 30 μm was obtained. Created.

A 9 μm thick aluminum foil (gas barrier layer) was dry laminated on the oxygen absorbing layer side of the obtained film 2, and a 15 μm thick stretched nylon 6 film and a 12 μm thick polyethylene terephthalate film were sequentially laminated on the aluminum foil. Dry lamination was performed to obtain an oxygen-absorbing multilayer film composed of outer layer (PET) 12 / adhesive / outer layer (nylon) 15 / adhesive / gas barrier layer (aluminum foil) 9 / oxygen absorbing layer 30 / heat seal layer 40. The tear strength of the obtained multilayer film in the TD direction was 3.0N.

Using the obtained oxygen-absorbing multilayer film, a 130 mm × 100 mm three-sided seal bag (heat seal width 10 mm) was prepared, filled with mango paste and sealed to prepare an oxygen-absorbing packaging bag. Further, a notch (I notch) having a length of 5 mm was made at the end of the heat seal portion of the packaging bag so as to be parallel to the TD direction of the multilayer film. The produced packaging bag was sterilized by heating at 90 ° C. for 30 minutes. When the appearance of the bag was observed after the treatment, there was no abnormality such as leakage in the heat seal part, and there was no deformation of the bag. Furthermore, when the packaging bag was torn open from the cut portion, it could be easily opened. Moreover, the packaging bag after heat processing was preserve | saved under 30 degreeC and 80% RH, and the oxygen concentration in a bag and the external appearance of a mango paste of a preservation | save 1 month were investigated. The oxygen concentration in the bag was reduced to 0.1% or less, the mango paste was not discolored, and the flavor was good.

Claims (5)

In an oxygen-absorbing film comprising a gas barrier layer comprising at least a gas barrier substance, an oxygen-absorbing resin layer comprising an iron-based oxygen absorbent in polyolefin and a heat-sealing resin layer from the outer surface side, heat sealing An oxygen-absorbing multilayer film excellent in tearability, wherein the tear strength in the TD direction (film width direction) of the resin layer is 5 N or less. The oxygen-absorbing multilayer film according to claim 1, wherein the polyolefin constituting the oxygen-absorbing resin layer comprises a polyethylene resin. The oxygen-absorbing multilayer film according to claim 1, wherein the gas barrier layer is an aluminum foil. An oxygen-absorbing packaging container comprising a part or all of the packaging container comprising the oxygen-absorbing multilayer film according to claim 1. A method for preserving an article, wherein the article is sealed in the oxygen-absorbing packaging container according to claim 4 and then heat-treated.