JPH1086291A - Deoxygenating multi-layered body and packaging vessel consisting of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the deterioration of oxygen barrier property at high temperature and high humidity and to improve heat resistance and moldability by a method wherein a gas barrier resin, constituted of a polymerized body containing a specified amount of amide structural unit, produced by polycondensation reaction between methaxylene diamine and adipic acid, is used to form a deoxygenating multi-layered body. SOLUTION: A deoxygenating multi-layered body is provided with a layer constitution constituted of an inner layer 10 (oxygen permeable layer)/an intermediate layer 20 (oxygen absorbing layer)/an adhesive layer 31/an outer layer 30 (gas barrier layer)/an adhesive layer 32/a protecting layer 33. The outer layer 30 is a gas barrier layer to play a role to preclude the inversion of oxygen from outside while the intermediate layer 20 is an oxygen absorbing layer. Polyamide or the copolymer of polyamide, which contains 90mol.% or more of amide structural unit produced by the polycondensation reaction between methaxylene diamine and diapic acid, is employed for the gas barrier resin for the outer layer 30. The polyamide is the polycondensated body of methaxylene diamine and adipic acid, which is also called as nylon MXD6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-like or film-like oxygen-absorbing multilayer body which does not decrease in oxygen barrier properties even when exposed to high-temperature and high-humidity conditions and has excellent moldability, and a packaging container comprising the same. About. More specifically, an oxygen-absorbing layer composed of an oxygen-absorbing resin composition containing an oxygen-absorbing composition as an intermediate layer, an outer layer of a gas-barrier layer composed of a gas-barrier resin and an inner layer of an oxygen-permeable layer composed of an oxygen-permeable resin. In a sheet-like or film-like deoxidizing multilayer body comprising: a polyamide containing 90 mol% or more of an amide structural unit formed by a polycondensation reaction between metaxylylenediamine and adipic acid as a gas barrier resin for an outer layer; The present invention relates to a deoxidizing multilayer body using a polyamide copolymer, and a packaging container having a deoxidizing performance, which is obtained by processing the multilayer body into a bag, a cup, a tray, a bottle, or the like.

[0002]

2. Description of the Related Art In recent years, as one of the oxygen-absorbing packaging techniques, a container is made of a multilayer material having an oxygen-absorbing resin layer in which an oxygen-absorbing composition is blended, thereby improving the gas barrier properties of the container and improving the container's gas barrier properties. Development of packaging containers having a deoxygenation function has been carried out. Packaging containers with deoxygenation function are usually
The oxygen-absorbing resin layer containing the oxygen-absorbing composition is used as an intermediate layer, and is composed of an oxygen-absorbing multilayer body having a gas-barrier outer layer on the outside and an oxygen-permeable inner layer on the inside. A deoxygenated multilayer body has been developed as a multilayer resin laminated structure that can be easily formed into a container such as a bag, a cup, a tray, or a bottle.

[0003] As a deoxidizing multilayer, for example, a deoxidizing composition disclosed in JP-A-57-146661, JP-A-2-72851, JP-A-4-90848, etc. A multi-layer film or sheet containing a layer dispersed in a polymer can be used. In Japanese Patent Publication No. 4-60826, an oxygen absorber is added to a gas-barrier thermoplastic resin layer provided in a multilayer material, and the oxygen-absorber in the gas-barrier resin obtains moisture during heat sterilization. A technique has been disclosed in which the gas barrier property of a deoxidized multilayer container is enhanced by being inspired to exhibit a deoxidizing ability. Also, JP-A-7-3
Japanese Patent Application Laid-Open No. 09323 discloses a method for removing unevenness in thickness of an inner layer caused by an ethylene-vinyl alcohol copolymer layer during molding of a container by using a propylene-based resin having a specific melting point and a softening point and an ethylene-vinyl alcohol copolymer. An oxygen multilayer molded container is disclosed. Japanese Patent Application Laid-Open No. 8-72942
No. 1 proposes a technique for improving the deoxidizing performance of a deoxidizing multilayer container.

In general, an ethylene-vinyl alcohol copolymer (abbreviated as EVOH) having excellent oxygen barrier properties has been used for the gas barrier resin layer as the outer layer of the deoxidizing multilayer container. However, when the deoxidizing multilayer container is used as a food packaging container, for example, steam heat sterilization after filling and sealing of food or retorting after filling and sealing of high moisture food, etc. Often exposed to However, when EVOH is exposed to high-temperature and high-humidity conditions, the oxygen barrier property is significantly reduced.
The oxygen-absorbing container having H as a gas barrier layer has a problem in that once subjected to the humid heat treatment, the oxygen-barrier property is deteriorated, and oxygen penetrating through the vessel wall cannot be sufficiently removed. Various attempts have been made to solve this, but there are still many problems to be solved in terms of molding technology and cost.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art deoxidizing multilayer body, and does not lower the oxygen barrier property even when exposed to high-temperature and high-humidity conditions. An object of the present invention is to provide a sheet-like or film-like oxygen-reducing multilayer body having excellent gas barrier properties and excellent moldability and a packaging container formed by using the same.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that an oxygen-absorbing layer composed of an oxygen-absorbing resin composition containing a deoxidizer composition has been formed into an intermediate layer. And, in a sheet-shaped or film-shaped deoxygenating multilayer body comprising an outer layer of a gas barrier layer made of a gas barrier resin and an inner layer of an oxygen permeable layer made of an oxygen permeable resin, the gas barrier resin is meta-xylylenediamine and 9 amide structural units formed by polycondensation reaction with adipic acid
It has been found that the problem can be easily solved by using a deoxygenating multilayer body composed of a polyamide or a polyamide copolymer (hereinafter, sometimes referred to as polymethaxylylene adipamide) containing 0 mol% or more. More preferably, it has been found that by blending an amorphous polyamide with a gas barrier resin such as polymethaxylylene adipamide and the like, it is possible to obtain a sheet-like or film-like deoxidizing multilayer body having excellent moldability. .

That is, an oxygen absorbing layer made of an oxygen absorbing resin composition containing a deoxidizer composition is used as an intermediate layer, and an outer layer of a gas barrier layer made of a gas barrier resin and an inner layer of an oxygen permeable layer made of an oxygen permeable resin are used. Or a polyamide comprising a gas-barrier resin containing 90 mol% or more of an amide structural unit formed by a polycondensation reaction between metaxylylenediamine and adipic acid in a sheet- or film-shaped deoxidizing multilayer body comprising: It is characterized by being composed of a copolymer.

[0008] Further, the oxygen-removable multilayer body of the present invention is characterized in that the gas barrier resin is a mixed resin obtained by adding and mixing amorphous polyamide to polymethaxylylene adipamide or the like.

[0009] The oxygen-absorbing multilayer body of the present invention is characterized in that the mixing ratio (% by weight) of the polymethaxylylene adipamide or the like and the amorphous polyamide is 80:20 to 30:70. .

Further, in the deoxidizing multilayer body of the present invention, the amorphous polyamide used when the gas barrier resin is a mixed resin is a polycondensate of terephthalic acid and trimethylhexamethylenediamine, 2,2- Copolycondensates of bis (P-aminocyclohexyl) propane with adipic acid and azelaic acid; copolycondensates of bis (3-methyl-4-aminocyclohexyl) methane with isophthalic acid and ω-aminododecanoic acid; diphenylmethane It is characterized by being at least one selected from a copolycondensate of a diisocyanate with a mixture of adipic acid, azelaic acid and isophthalic acid, and a copolycondensate of terephthalic acid and isophthalic acid with hexamethylenediamine.

[0011] In the deoxidizing multilayer body of the present invention, the amorphous polyamide used when the gas barrier resin is a mixed resin has a melt flow rate of ASTM.
Based on D1238, temperature 230 ° C, load 2.16kg
It is not more than 8 g / 10 minutes when measured under the condition of f.

Further, in the oxygen-reducing multilayer body of the present invention, the amorphous polyamide used when the gas barrier resin is a mixed resin has a glass transition point of 80 to 150 ° C.

Further, the oxygen-removable multilayer body of the present invention is characterized in that a protective layer made of a gas barrier performance protective resin is formed on the outer surface of the gas barrier layer.

Further, in the packaging container according to the present invention, the oxygen-absorbing multilayer body according to the above-mentioned invention, wherein the gas barrier resin is meta-xylylene adipamide or the like, has at least a part of the wall surface of the container and the inner layer in the container. It is characterized by being arranged, used and molded.

Further, in the packaging container of the present invention, the oxygen barrier multilayer body of the present invention, wherein the gas barrier resin is a mixture of metaxylylene adipamide and an amorphous polyamide, is provided on at least a part of the wall surface of the container, and It is characterized in that the inner layer is disposed inside the container and used for molding.

The deacidified multilayer body of the present invention comprises a polyamide or polyamide copolymer containing 90 mol% or more of an amide structural unit formed by a polycondensation reaction between metaxylylenediamine and adipic acid in the gas barrier resin of the outer layer. Due to the use, even when exposed to high temperature and high humidity conditions, the oxygen barrier property does not decrease and the gas barrier property with excellent heat resistance is provided. Furthermore, by blending the amorphous polyamide with the gas barrier resin such as meta-xylylene adipamide and the like, the container is excellent in sheet moldability, has a sufficiently wide allowable temperature range of molding temperature, and has a relatively low temperature range. It becomes a deoxidizable multilayer body that can be molded. Further, the packaging container of the present invention uses the above-described deoxidizing multilayer body, and is formed by disposing the inner layer of the multilayer body inside the container. It is a highly functional container that removes oxygen.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION
The multilayer container is sometimes simply referred to as a multilayer body) and the multilayer container has an oxygen-absorbing layer composed of an oxygen-absorbing resin composition in which a deoxidizer composition is mixed with a thermoplastic resin as an intermediate layer, and is composed of metaxylylenediamine and adipic acid. A gas barrier layer composed of a gas barrier resin of polyamide or polyamide copolymer containing 90 mol% or more of an amide structural unit formed by a polycondensation reaction of is disposed on an outer layer, and an oxygen permeable layer composed of an oxygen permeable resin is disposed on an inner layer. Arranged film or sheet-like multilayer body,
And this multilayer body is a multilayer packaging container formed into a packaging container such as a bag, a cup, a tray, and a bottle with its inner layer inside the container, or used as a member of the packaging container, and has a deoxidizing ability. It functions as a multilayer body and a container.

As a specific example of the layer structure of the deoxidizing multilayer body of the present invention, for example, as shown in FIG. 1, inner layer 10 (oxygen permeable layer) / intermediate layer 20 (oxygen absorbing layer) / adhesive layer 31 / outer layer 3
0 (gas barrier layer) / adhesive layer 32 / protective layer 33. This multilayer body is not limited to being composed only of the main layers, the inner layer, the intermediate layer, and the outer layer, and any of the respective layers can be further added with other layers as necessary.
The above specific example shows a case where one or more other layers are added to both sides of the outer layer 30 (gas barrier layer). The function of the inner layer, the intermediate layer, and the outer layer, which are the main layers of the packaging container of the present invention formed by using the multilayer body, will be described. The outer layer 30 is a gas barrier layer and functions to prevent oxygen from entering from outside. And an oxygen absorbing layer of the intermediate layer 20. The outer layer cannot completely prevent the oxygen from entering and cannot absorb oxygen, but also functions to absorb oxygen in the container through the inner layer. A permeable layer that acts as an isolation layer that prevents direct contact between the oxygen absorption layer of the intermediate layer and the contents of the container, and quickly releases oxygen in the container so that the oxygen absorption layer can fully perform its oxygen absorption function. It also plays the role of transmitting light efficiently.

Hereinafter, the deoxidized multilayer body of the present invention will be described with reference to the drawings. As the gas barrier resin of the outer layer, a polyamide or polyamide copolymer containing 90 mol% or more of an amide structural unit formed by a polycondensation reaction between metaxylylenediamine and adipic acid is used. The polyamide is a polycondensate of meta-xylylenediamine and adipic acid, and is also called nylon MXD6. In the present invention, the amide structural unit, that is, -CONH
Metaxylylenediamine and adipic acid have been mentioned as raw materials for the polycondensation reaction for producing-, but these raw material compounds are only listed as typical examples for producing -CONH-, and those producing -CONH- Any precursor may be used. Therefore, the concept of meta-xylylenediamine in the present invention, for example, hydrochloride,
Various derivatives are also included, and the concept of adipic acid also includes various derivatives such as acid halides and esters, for example, and the types of these raw materials do not affect the technical scope of the present invention.

Further, the polyamide copolymer may be a diamine or dicarboxylic acid other than metaxylylenediamine and adipic acid as raw materials of the polyamide (in this case, it is not limited to free diamine or free dicarboxylic acid). The same as in the case of meta-xylylenediamine and adipic acid as the raw materials for polyamide according to the present invention), and further as a copolymer containing as a comonomer an amino acid having both an amino group and a carboxyl group (including lactam). Means polyamide. In the polyamide copolymer in the present invention, the intended purpose cannot be achieved if the amide structural unit content based on diamine or dicarboxylic acid other than meta-xylylenediamine and adipic acid is too large, and meta-xylylenediamine and adipic acid cannot be achieved. Must contain 90 mol% or more of the amide structural unit formed by the polycondensation reaction of In addition, the gas barrier resin includes
As long as the object of the present invention is not impaired, a crystalline polyamide other than the above polyamide or polyamide copolymer may be contained, but the content of the crystalline polyamide is preferably 30% by weight or less.

Further, in order to improve the moldability of the deoxidized multilayer body, the gas barrier resin is preferably a mixed resin of the above polyamide or a polyamide copolymer and an amorphous polyamide. . The amorphous polyamide referred to herein is also called amorphous nylon or transparent nylon, and nylon 6, nylon 6
Unlike a straight-chain aliphatic nylon such as 6, a special nylon in which crystallization of the polymer hardly occurs or in which the crystallization rate is extremely small, examples of the amorphous polyamide used in the present invention include, for example, , A polycondensate of terephthalic acid and trimethylhexamethylenediamine, 2,2-
Copolycondensates of bis (P-aminocyclohexyl) propane with adipic acid and azelaic acid; copolycondensates of bis (3-methyl-4-aminocyclohexyl) methane with isophthalic acid and ω-aminododecanoic acid; diphenylmethane Copolycondensates of a mixture of diisocyanate with adipic acid, azelaic acid and isophthalic acid, and copolycondensates of terephthalic acid and isophthalic acid with hexamethylenediamine are preferably used.

The amorphous polyamide used in the present invention includes test conditions in accordance with ASTM D1238;
The melt flow rate (MFR) at a temperature of 230 ° C. and a load of 2.16 kgf is preferably 8 g / 10 min or less, particularly preferably 6 g / 10 min or less. When an amorphous polyamide having an MFR of more than 8 g / 10 minutes is used, the viscosity of the gas barrier resin becomes too low during sheet formation of the deoxidized multilayer body, so that a multilayer sheet having a stable thickness cannot be obtained.

Further, the amorphous polyamide used for improving the thermoforming processability of the deoxidized multilayer body preferably has a glass transition point of 80 to 150 ° C. By adding the amorphous polyamide having the glass transition point to the polyamide or the polyamide copolymer, when molding the multilayer body into a container, it is possible to prevent the occurrence of uneven stretching and uneven thickness due to crystallization of the resin, and a wide range. Good container molding can be performed under the heat molding conditions. For example, even when the sheet surface temperature in thermoforming is high or low, or when the heating time is long or short, unevenness in elongation and thickness unevenness does not occur.

The mixing ratio of the gas barrier resin such as polymethaxylylene adipamide and the amorphous polyamide mixed therein is preferably 80:20 to 30: 70% by weight.
80:20 to 40: 60% by weight is more preferred. When the proportion of the amorphous polyamide is less than 20% by weight, a sufficient improvement effect on the formability of the sheet or film into a container cannot be obtained, and when it exceeds 70% by weight, the content becomes too large.
Conversely, problems arise in the formability of the sheet or film itself, and the properties of the above polymetaxylylene adipamide and the like are impaired, which is not preferred. By appropriately blending the amorphous polyamide at a ratio in the above range, gas barrier properties such as polymethaxylylene adipamide,
In particular, it is possible to obtain a deoxygenated multilayer body having good thermoformability while maintaining the property that the oxygen barrier property does not decrease when exposed to high temperature and high humidity conditions.

The thickness of the gas barrier layer made of the gas barrier resin is not necessarily limited. However, in the case where the multilayer body is further molded and stretched, the thickness of the gas barrier layer before molding is taken into consideration in consideration of the fact that the thickness is reduced by stretching. Is required to be such a thickness that the gas barrier property is not impaired by stretching.

The outer layer is a gas barrier layer made of a gas barrier resin. If necessary, a resin having another function or a material other than the resin is laminated on the inner and outer surfaces of the gas barrier layer to form a multilayer, and the function of the gas barrier layer is improved. Can be made more effective. For example, a protective layer made of another resin is provided outside the gas barrier layer to protect the gas barrier resin layer. Polyolefins such as polyethylene and polypropylene, mixtures or modified resins thereof, polyesters such as polyethylene terephthalate, and the like are used for the other resin layer, and a coloring layer such as a pigment is used for the protective layer, if necessary. Additives such as agents, fillers, antistatic agents and stabilizers may be appropriately compounded. Further, an adhesive layer may be provided for improving the adhesion between the outer gas barrier layer and the protective layer or the intermediate layer made of the other resin.

The oxygen-absorbing resin composition of the intermediate layer is a resin composition obtained by kneading and dispersing an oxygen-absorbing composition in a resin. Here, the oxygen scavenger composition is not particularly limited, and a known oxygen scavenger composition can be used, for example, metal powder such as iron powder,
A deoxidizing agent composition using a reducing inorganic substance such as an iron compound, a polyhydric phenol, a polyhydric alcohol, a reducing organic substance such as ascorbic acid or a salt thereof, or a metal complex as a main agent of the oxygen absorption reaction is used. . Among them, in order to make the oxygen-reducing multilayer body excellent in oxygen-removing performance,
An oxygen scavenger composition containing iron powder as a main component is preferred, and an oxygen scavenger composition comprising iron powder and a metal halide is particularly excellent. In particular, iron powder whose surface is coated with a metal halide is preferably used.

The iron powder used in the oxygen scavenger composition is not particularly limited as long as it is dispersible in a thermoplastic resin and can cause an oxygen scavenging reaction. Can be used. The iron powder has an average particle size of preferably 5 to 200 μm or less, particularly preferably 50 μm or less. In order to form a smooth oxygen absorbing layer, it is preferable that the size of the iron powder particles be fine without exceeding the thickness of the oxygen-absorbing resin layer.

As the metal halide, for example, chlorides, bromides and iodides of alkali metals or alkaline earth metals are used, and chlorides such as lithium, potassium, sodium, magnesium, calcium and barium are preferably used. The compounding amount of the metal halide is 100
It is preferably 0.1 to 20 parts by weight, more preferably 0.1 to 5 parts by weight per part by weight. In particular, the amount of the metal halide can be reduced by attaching the metal halide to the iron powder.

The oxygen scavenger composition preferably has a low water content. The oxygen scavenger composition preferably has a water content of 0.2%.
% By weight or less, more preferably 0.1% by weight or less.
When using the multilayer body of the present invention as a packaging material, the oxygen scavenger composition obtains moisture and exhibits an oxygen absorbing function.
The oxygen scavenger composition of the iron powder base is used as a granular material, and its size is preferably from 5 to 200 μm, more preferably from 5 to 50 μm in average particle size.

The resin to be mixed with the deoxidizing composition is preferably a thermoplastic resin having a Vicat softening point of 110 ° C. to 130 ° C. By using a thermoplastic resin having a softening point within the above range, it is possible to prevent local overheating around the iron powder in the resin during thermoforming of the multilayer body, and to mold into a container having a good appearance. Becomes Specific examples of the thermoplastic resin include, for example, polyolefins such as polyethylene, polypropylene, polybutadiene, and polymethylpentene, elastomers, modified products thereof, and mixed resins thereof. Preferably, a mixture of polyethylene and polypropylene, a propylene-ethylene random copolymer, or a mixed resin thereof is used.

The mixing ratio of the oxygen scavenger composition in the oxygen absorbing resin composition is preferably 2 to 93% by weight, and 10 to 70% by weight.
% Is more preferred. If the mixing ratio is less than 2% by weight, the deoxidizing performance is remarkably reduced, and if it is more than 93% by weight, the processability of the deoxidizing multilayer body or the packaging container using the same is unpreferably deteriorated. In addition, it is preferable to add calcium oxide to the oxygen-absorbing resin composition containing the oxygen scavenger composition in order to prevent foaming and to improve the aging property, and further, if necessary, an organic or inorganic dye or the like. Colorants such as pigments, dispersants such as silanes and titanates, water-absorbing agents based on polyacrylic acid, fillers such as silica and clay, and gas adsorbents such as zeolite and activated carbon can be added. The layer thickness of the oxygen-absorbing layer composed of the oxygen-absorbing resin composition is preferably 1,000 μm or less, more preferably 500 μm
The following is more preferred.

As the oxygen-permeable resin for the inner layer, a thermoplastic resin is preferably used. Examples thereof include polyolefins such as polyethylene, polypropylene, polybutadiene, and polymethylpentene, and modified products thereof, or graft polymers thereof with a silicon resin. Polyesters such as polyethylene terephthalate, polyamides such as nylon 6 and nylon 66, ionomers, elastomers and the like are used. In addition, the oxygen-permeable resin of the inner layer is preferably compatible with the oxygen-absorbing resin of the intermediate layer. By selecting resins compatible with each other, the respective resins of the inner layer and the intermediate layer are co-extruded and laminated and bonded. It is possible to do. In addition, the inner resin layer often plays the role of a sealant layer as the innermost layer of the packaging container, and it is preferable to select a heat-sealable resin, but it is also possible to further provide a heat-sealable layer on the inner surface side. Good. Incidentally, the resin of the inner layer or the heat-sealing layer may include a coloring agent such as a pigment, a filler,
Additives such as an antistatic agent and a stabilizer can be blended.

As described above, the inner layer plays a role of a separating layer between the contents contained in the container and the oxygen absorbing layer, and also needs to have a function of transmitting oxygen quickly and efficiently. Regardless of the presence or absence of other layers and the thickness of the inner layer itself, the oxygen permeability of the inner layer is at least 100.
It must be at least cc / m ² · day · atm (23 ° C., 100% RH). For this reason, the thickness of the inner layer
It is preferable to reduce the thickness as much as possible within the range permitted by workability and cost, and to increase oxygen permeability. Further, as apparent from the above-mentioned role, the inner layer is not necessarily limited to the non-porous resin layer, but may be a microporous membrane or a nonwoven fabric made of the thermoplastic resin.

Each of the above-mentioned layers can be laminated by appropriately combining known methods such as coextrusion, various laminating methods and various coating methods, depending on the properties of each layer material, processing purpose, processing step and the like. For example, when the deoxygenating multilayer body is a resin laminate, the resin is melt-kneaded in an extruder corresponding to each layer, and then is simultaneously melt-extruded through multiple multilayer dies such as a T-die and a circular die to obtain a multilayer film. Or a sheet can be manufactured. Further, the molten resin can be co-injected or sequentially injected into an injection mold through a multi-layered multiple die using an injection machine, so that a multi-layer container having a predetermined shape can be molded at a time.

The oxygen-absorbing multilayer body according to the present invention is a flat or tubular sheet or film (including a tube, a parison, etc.) obtained by the above-mentioned various methods.
Using these materials, a container having a predetermined shape can be formed by a forming method such as vacuum forming, pressure forming, and plug assist forming. In this case, the molding temperature varies depending on the melting point and softening point of the resin, but the gas barrier resin layer is a mixed resin of the polyamide or the polyamide copolymer and the amorphous polyamide.
The temperature can be selected in the range of 5 ° C., and molding in a relatively low temperature range becomes possible. Heating for container molding can be performed by contact heating or non-contact heating.However, contact heating can reduce the temperature gradient generated in the deoxidizing multilayer body as much as possible, It is possible to reduce poor appearance of the container such as uneven stretching.

According to the present invention, the oxygen-absorbing multilayer body is used for part or all of the hermetically sealed packaging container to absorb oxygen which may slightly enter from outside the container and oxygen in the container. As a result, it is possible to prevent deterioration of the contents stored in the container due to oxygen. That is, packaging by using a film or sheet-shaped deoxygenated multilayer body into containers such as bags, cups, trays, bottles and the like, and also by using them as members such as container lids and top seal films. Deoxidation performance is imparted to the container.

[0038]

EXAMPLES The present invention will be described in more detail with reference to examples. Note that the present invention is not necessarily limited to the embodiments. Example 1 Iron powder (average particle diameter 35 μm, maximum particle diameter 80 μm) was placed in a vacuum mixing dryer equipped with a heating jacket, and heated at 130 ° C.
While heating and drying under reduced pressure of 0 mmHg, 3 parts by weight of a mixed aqueous solution obtained by mixing calcium chloride and water at a ratio of 1: 1 with respect to 100 parts by weight of iron powder is sprayed to attach calcium chloride to the iron powder surface. A granular oxygen scavenging composition was prepared.
Next, a propylene-ethylene random copolymer (manufactured by Sumitomo Chemical Co., Ltd., trade names; Sumitomo Noblen S131, MFR; 1.2 g / 1) was used in a 45 mmφ co-rotating twin-screw extruder.
0 min (230 ° C, 2.16 kgf, ASTM D123
8), Vicat softening point: 119 ° C (JIS K675)
8)) and the oxygen scavenger composition were kneaded at a mixing ratio of 3: 2 (weight ratio), extruded, cooled with a net belt with a blower, passed through a pelletizer, and pellets of an oxygen-absorbing resin composition were obtained. .

Next, using a four-layer, six-layer, multi-layer sheet forming apparatus comprising first to fourth extruders, a feed block, a T-die, a cooling roll, and a sheet take-off machine, the first extruder; 14% by weight propylene-ethylene block copolymer (manufactured by Chisso Corporation, trade name: Nisso Polypro XF1936, MFR; 0.4 g / 10 min (230 ° C., 2.16 kgf, ASTM D123)
8)), a second extruder; the oxygen-absorbing resin composition,
Extruder: Polymeta-xylylene adipamide (manufactured by Mitsubishi Gas Chemical Co., Ltd., polyamide containing 100 mol% of an amide structure formed by a polycondensation reaction between polymetaxylylenediamine and adipic acid; trade name: MX nylon 6007) , And a fourth extruder; maleic anhydride-modified polypropylene, were extruded to obtain a sheet having a multilayer structure shown in Table 1. The layer structure of the multilayer sheet is composed of an oxygen-permeable layer (inner layer) / oxygen-absorbing layer (intermediate layer) / adhesive layer / gas barrier layer (outer layer) / adhesive layer / protective layer (outermost layer). Used a propylene-ethylene block copolymer to which titanium oxide as a white pigment was added in order to cover the oxygen absorbing layer.

[0040]

[Table 1]

Next, the above multilayer sheet was plug-assisted at about 180 ° C. using a vacuum forming machine to obtain a tray-shaped container. The pasta was put into the obtained tray-shaped container, and as shown in FIG. 2, the gas barrier properties of PET film (20 μm) / aluminum foil (10 μm) / unstretched polypropylene film (50 μm, heat seal layer) were provided at the container opening. The tray-shaped container was sealed by heat-sealing the aluminum foil laminated film. 121 ° C. in a container with pasta sealed
-After performing the retort treatment for 30 minutes, it was stored at 23 ° C for 30 days. During this time, the oxygen concentration in the sealed container was measured daily using a gas chromatograph, and on the 30th day of storage, the container was opened to check the storage condition of the pasta. Table 2 shows the results.

Example 2 The gas barrier resin in the multilayer sheet of Example 1 was prepared by mixing 70% by weight of polymethaxylylene adipamide (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: MX nylon 6007) with nylon as in Example 1. 66 (manufactured by Ube Industries, Ltd., trade name; Ube Nylon 2026B) except that a mixed resin consisting of 30% by weight was obtained in the same manner as in Example 1 to obtain a multilayer sheet.
Next, a tray-shaped container was produced. Using the obtained tray-shaped container, a storage test of pasta was performed in the same manner as in Example 1. Table 2 shows the results.

Comparative Example 1 The procedure of Example 1 was repeated except that the gas barrier resin in the multilayer sheet of Example 1 was ethylene vinyl alcohol copolymer (trade name: EVAL EP-T101, manufactured by Kuraray Co., Ltd.). To obtain a multilayer sheet, and then a tray-shaped container was produced. Using the obtained tray-shaped container, a storage test of pasta was performed in the same manner as in Example 1. Table 2 shows the results.

[0044]

[Table 2]

As is clear from Table 2, in the case of Comparative Example 1,
The oxygen concentration in the sealed container was almost the same as in Examples 1 and 2 immediately after the retort treatment, but about 5% on the seventh day and about 3% on the 30th day, and oxygen remained. Oxygen in the inside was not sufficiently absorbed, so that the pasta stored for 30 days was discolored and the flavor was significantly impaired. this is,
Exposure to high-temperature and high-humidity conditions due to the retort treatment deteriorated the oxygen gas barrier properties of the gas barrier resin, so it was not possible to completely shut off oxygen entering from outside the container.
It also indicates that oxygen in the container was not sufficiently absorbed. In contrast, in the case of Examples 1 and 2, the oxygen concentration in the container in which the pasta was sealed was kept at 0.1% or less from the 7th day, and the pasta also had no fading and had a good flavor. It had been. These differences indicate that the gas barrier resin layer of the present invention has excellent resistance to high temperature and high humidity conditions.

Example 3, Comparative Example 2 A propylene-ethylene random copolymer (Sumitomo) was prepared using a pelletizer consisting of a twin screw extruder / strand die / blower cooler / cutter containing two screws (50 mm diameter). Product name: Sumitomo Noblen S
131) and an oxygen scavenger composition obtained by coating iron powder (average particle size: 30 μm) with 1% by weight of calcium chloride:
The mixture was kneaded at a ratio of 40 (weight ratio) to pelletize the oxygen-absorbing resin composition. Next, using a five-type six-layer co-extrusion multilayer sheet manufacturing apparatus, pellets of the oxygen-absorbing resin composition (for the intermediate layer) and polymethaxylylene adipamide (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: MX nylon) 6007) and an amorphous polyamide (manufactured by Mitsui DuPont Polychemicals, Inc.)
Copolycondensates of terephthalic acid and isophthalic acid with hexamethylenediamine. Product name; Sheila PA3426, M
FR; 3.5 (g / 10 minutes 230 ° C. 2.16 kg
f, ASTM D1238)) and 5% by weight of titanium oxide (for protective layer) and 14% by weight of propylene-ethylene block copolymer (trade name: Chissopolypro XF1936, manufactured by Chisso Corp.) % (For the inner layer) and five kinds of resins of maleic anhydride-modified polypropylene (for the adhesive layer) were extruded to produce a five-layered and six-layered multilayer sheet having the same structure as in FIG. Table 3 shows the layer configuration of the multilayer sheet.

[0047]

[Table 3]

In the production of the multilayer sheet, the ratio of the amorphous polyamide to the mixed resin of polymetaxylylene adipamide and the amorphous polyamide as the gas barrier resin to be used was changed to 0, 20, and 50% by weight. Three types of multilayer sheets were produced. For comparison, an ethylene-vinyl alcohol copolymer (trade name: EVAL EP-T101, manufactured by Kuraray Co., Ltd.) was used as a gas barrier resin.
Was used to produce a multilayer sheet in the same manner. As a result, even when the amorphous polyamide ratio was 0, 20 and 50% by weight, the ethylene-vinyl alcohol copolymer (EVO
In the case of H), there was no particular problem in producing a multilayer sheet by coextrusion.

Next, for each of the four types of multi-layer sheets having a good surface condition using an amorphous polyamide ratio of 0, 20 and 50% by weight and using EVOH, a tray-like container (internal volume 350 cc, surface area 200 cm ² ) 1, 2,
3 and thermoforming. For each container, plug-assist molding was performed by changing the heating temperature during molding to 160 ° C., 165 ° C., and 175 ° C., and the resulting container was evaluated based on the appearance, particularly the occurrence of thickness unevenness of the gas barrier resin layer. The moldability was evaluated. The evaluation criteria were A;
B: good, C: unsuccessful, and the results are shown in Table 4.

[0050]

[Table 4] Note) Molding container 4: Use of ethylene-vinyl alcohol copolymer as barrier resin

As is clear from Table 4, in the case of the molding containers 2 and 3 in which a multilayer sheet having a non-crystalline polyamide ratio of 20 to 50% by weight to the polymetaxylylene adipamide of the gas barrier resin was molded. Stretchability,
Since the deep drawability is good, and the elongation unevenness due to the crystallization of the resin is suppressed, a molded article having a good appearance can be obtained at each molding temperature, and the container processing moldability of the sheet was extremely good. . On the other hand, in the case of the molding container 1 having an amorphous polyamide ratio of 0, although the molding temperature was relatively good at around 160 ° C., even if the heating temperature was slightly increased, the stretching unevenness and the thickness unevenness were reduced. As a result, a container having a good appearance was not obtained, and the width of the allowable molding temperature range was narrow. Also, in the case of the molded container 4 using EVOH manufactured for comparison, if the heating temperature was low, unevenness in elongation and unevenness in thickness due to insufficient heating were observed, and a container having a good appearance could not be obtained. The temperature was set to 175 ° C. to obtain a container having a good appearance.

Example 4 300 g of boiled pasta was hot-packed into a tray-shaped molding container 3 (amorphous polyamide ratio: 50% by weight) obtained at a molding temperature of 165 ° C. in Example 3, and a gas barrier film (polyvinylidene chloride) was obtained. Coated stretched polypropylene film (15 μm) / unstretched polypropylene film (60 μm)
m, the laminated film) on the heat sealing side) was used as a top film, sealed, and stored at room temperature for 30 days. During this time, the daily change of the oxygen concentration inside the container was examined. Save 3
0 days later, a hole was made in the top film of the molded container 3 in which the spaghetti was sealed, and a microwave oven (Mitsubishi Electric Corporation)
(Model, RR50, 500 W) for 3 minutes, and then the container was opened to examine the state of the inner and outer surfaces of the container and the flavor of the pasta. The results show that, as shown in Table 5, the deoxygenation performance of the container is also good, and the storage condition of the pasta is also good,
Also, even after microwave heating, no deformation or change in the surface state was observed in the container.

[0053]

[Table 5]

Example 5 The tray-shaped container 2 (amorphous polyamide ratio 20% by weight) and the tray-shaped container 3 (amorphous polyamide ratio 50% by weight) obtained at a molding temperature of 165 ° C. in Example 3 were added. ,
Each was filled with 200 g of kelp wrap and 120 g of kelp soup (water activity of the filling: 1.0), and an aluminum foil laminated film (PET film (15 μm) / aluminum foil (20 μm))
/ Unstretched polypropylene film (laminated film of 50 μm, heat seal side) was used as a top seal and sealed. This container, in which the kelp wrap was hermetically sealed, was subjected to a heat treatment at 120 ° C. for 30 minutes using an air steam type high-temperature and high-pressure sterilizer, and then cooled and stored at room temperature for 30 days. During this period, the change in the oxygen concentration inside the container over time was examined. On the 30th day, the container was opened, and the appearance and flavor of the kelp roll were examined to evaluate the state of maintaining the quality. Table 6 shows the results.

Comparative Example 3 A kelp-wrapped storage test was performed in the same manner as in Example 5 using the tray-shaped molding container 4 (using EVOH) obtained in Comparative Example 2 at a molding temperature of 175 ° C. Table 6 shows the results.

[0056]

[Table 6] Note) Quality evaluation of kelp winding Appearance: 3; good 2: slightly discolored 1: large discoloration Flavor: 3; good 2: slightly oxidized odor 1: large oxidized odor

As is evident from the results in Table 6, in Example 5 using the multilayer sheet molded container of the present invention, even if the container in which the kelp roll containing the broth was sealed was retorted, oxygen was efficiently removed. It was absorbed and removed, thereby preventing oxidative deterioration, and the kelp winding had good quality such as appearance and flavor. On the other hand, in Comparative Example 3 in which a multilayer molded container using EVOH was used for the barrier resin layer, the deoxygenation performance of the container was reduced and oxygen could not be sufficiently absorbed and removed.
The appearance could not be maintained. As is clear from Comparative Examples 2 and 3, when EVOH was used as the barrier resin, the molding temperature was relatively high when the sheet was formed into a container, and the obtained container was subjected to retort treatment. Exposure to high-temperature and high-humidity conditions as described above causes a problem in that the barrier properties are reduced and the deoxidizing performance of the container is reduced.

[0058]

According to the present invention, there is provided a deoxygenated multilayer body comprising a polyamide or a polyamide copolymer containing 90 mol% or more of an amide structure formed by a polycondensation reaction between metaxylylenediamine and adipic acid in the gas barrier resin of the outer layer. By using the coalesced gas, the oxygen barrier property does not decrease even when exposed to high-temperature and high-humidity conditions, and the gas barrier property with excellent heat resistance is provided. Furthermore, by blending the above polyamide or polyamide copolymer of the gas barrier resin with an amorphous polyamide, it is excellent in sheet moldability, and the allowable temperature range of the molding temperature is sufficiently wide and the container is formed in a relatively low temperature range. It becomes a deoxidizable multilayer body that can be formed.

The deacidified multilayer body of the present invention is excellent in deoxygenation function and excellent in gas barrier properties, particularly in that oxygen barrier properties are not reduced even when exposed to high temperature and high humidity conditions. Is a multilayer structure excellent in resin processability. Therefore, the packaging container made of the deacidified multilayer body of the present invention does not lower the oxygen barrier property even when heat sterilization is performed, can efficiently absorb oxygen in the container, and exhibits a quality maintaining effect. In particular, it is useful as a heat-resistant deacidifying container capable of heat sterilization such as hot water sterilization, boiling sterilization, and retort sterilization. For this reason, the packaging container according to the present invention can be widely used as a packaging container for articles that require heat sterilization, such as foods including high moisture foods, pharmaceuticals such as infusions, and the like. Further, the deoxidized resin layer has excellent microwave resistance and is useful as a food packaging container to be heated and cooked as it is in a microwave oven.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of a deoxidizing multilayer sheet of the present invention.

FIG. 2 is a cross-sectional view of an example of a packaging container formed by using the deoxidizing multilayer sheet of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Inner layer; Oxygen permeable layer 20 Intermediate layer; Oxygen absorption layer 30 Outer layer; Gas barrier layer 31 Adhesive layer 32 Adhesive layer 33 Protective layer 1 Container formed using the sheet-shaped deoxidizing multilayer body according to the present invention 2 Gas barrier film 3 Food

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08J 7/04 CES C08J 7/04 CESP

Claims (9)

[Claims] 1. An oxygen absorbing layer comprising an oxygen absorbing resin composition containing an oxygen scavenger composition as an intermediate layer, an outer layer of a gas barrier layer comprising a gas barrier resin and an inner layer of an oxygen permeable layer comprising an oxygen permeable resin. Or a polyamide comprising a gas-barrier resin containing 90 mol% or more of an amide structural unit formed by a polycondensation reaction between metaxylylenediamine and adipic acid in a sheet- or film-shaped deoxidizing multilayer body comprising: A deoxygenated multilayer body comprising a copolymer. 2. The oxygen-removable multilayer body according to claim 1, which is a mixed resin obtained by adding and mixing an amorphous polyamide to a polyamide or a polyamide copolymer. 3. The mixing ratio (% by weight) of the polyamide or the polyamide copolymer and the amorphous polyamide is 80: 2.
The deoxidized multilayer body according to claim 2, wherein the ratio is from 0 to 30:70. 4. An amorphous polyamide comprising a polycondensate of terephthalic acid and trimethylhexamethylenediamine, 2,2-
Copolycondensates of bis (P-aminocyclohexyl) propane with adipic acid and azelaic acid; copolycondensates of bis (3-methyl-4-aminocyclohexyl) methane with isophthalic acid and ω-aminododecanoic acid; diphenylmethane The copolymer according to claim 2, which is at least one selected from a copolycondensate of diisocyanate and a mixture of adipic acid, azelaic acid and isophthalic acid, and a copolycondensate of terephthalic acid and isophthalic acid with hexamethylenediamine. Deoxidized multilayer body. 5. The deoxygenation method according to claim 2, wherein the melt flow rate of the amorphous polyamide is 8 g / 10 min or less as measured according to ASTM D1238 at a temperature of 230 ° C. and a load of 2.16 kgf. Multi-layered body. 6. The amorphous polyamide has a glass transition point of 80.
The deoxidizing multilayer body according to claim 2, wherein the temperature is from 150 ° C to 150 ° C. 7. The oxygen-removable multilayer body according to claim 2, wherein a protective layer made of a gas barrier performance protective resin is formed on an outer surface of the gas barrier layer. 8. A packaging container formed by using the deoxidizing multilayer body according to claim 1 on at least a part of a wall surface of the container and an inner layer disposed inside the container. 9. A packaging container formed by using the deoxidizing multilayer body according to claim 2 on at least a part of the wall surface of the container and disposing the inner layer inside the container.