JP2003335379A - Method of preserving molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of preserving various kinds of moldings made by use of an oxygen-absorbing polyamide resin composition for a long time without degrading the ability of the moldings to absorb oxygen for a period of time until the moldings are post-processed or filled with contents such as food. <P>SOLUTION: The molding employing the oxygen-absorbing polyamide resin composition is preserved by means of a packaging material and a packaging container comprising a combination of an oxygen-absorbing composition and a material having oxygen barrier properties. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for storing molded articles. Specifically, it is a method of storing a molded article using an oxygen-absorbing polyamide resin composition, which can maintain quality for a long period of time without deteriorating the oxygen-absorbing function and mechanical properties of the molded article. The present invention relates to a method for storing molded articles.

[0002]

2. Description of the Related Art Metal cans and glass bottles, which have been conventionally used as packaging containers that block the ingress of oxygen from the outside and are excellent in storage stability of contents, are made of an oxygen barrier thermoplastic resin in view of processability and cost. It is recommended that the used plastic packaging containers be replaced. The oxygen-barrier thermoplastic resin has low permeability to gaseous substances such as oxygen and carbon dioxide, is easy to process, and is transparent and has sufficient mechanical strength. Widely used polyamide (hereinafter abbreviated as nylon MXD6) obtained from polycondensation reaction of ethylene-vinyl alcohol copolymer or diamine component containing metaxylylenediamine as a main component and dicarboxylic acid component containing adipic acid as a main component Has been done.
However, in the case of a packaging container made of metal or glass, the gas permeation from the outside of the container to the inside of the container is substantially zero, whereas in the case of a packaging container made of an oxygen barrier thermoplastic resin, Gas permeation from the outside of the container to the inside of the container occurs at a non-negligible level, and the amount of gas permeation tends to increase depending on the environment in which the packaging container is stored. There was a problem with long-term storage.

Recently, a small amount of a transition metal compound is added to and mixed with nylon MXD6 to impart an oxygen absorbing function to nylon MXD6, and this is used as an oxygen barrier material constituting a container or a packaging material. Nylon MXD6 absorbs permeated oxygen and nylon MXD6 also absorbs oxygen remaining in the container, thereby improving the storage stability of contents more than conventional containers using an oxygen barrier thermoplastic resin. Is being put to practical use.

A molded article using nylon MXD6 having an oxygen absorbing function begins to absorb oxygen when left in an atmosphere containing oxygen, for example, in the air, so that the oxygen absorbing capacity gradually decreases, When processed into various packaging materials and used, it may not be possible to exhibit a sufficient oxygen absorption capacity, but it has not been known so far about a method for preventing a decrease in the oxygen absorption capacity.

[0005]

The object of the present invention is to solve the above-mentioned problems and to carry out the post-processing of various molded articles using the oxygen-absorbing polyamide resin composition, or the storage of foods and the like. It is an object of the present invention to provide a method for storing a molded article for a long period of time without deteriorating the oxygen absorption capacity of the molded article before filling the article.

[0006]

Means for Solving the Problems As a result of intensive investigations by the present inventors on a method for solving the above problems, a molded article using an oxygen-absorbing polyamide resin composition was found to have an oxygen-absorbing composition and an oxygen-barrier property. By using packaging materials and packaging containers that combine materials, it can be stored for a long period of time.
The inventors have found that the oxygen storage function can be preserved without lowering the function, and have completed the present invention.

That is, the present invention relates to the VI of the Periodic Table of the Elements.
A method for storing a molded article using an oxygen-absorbing polyamide resin composition containing one or more metal atoms selected from Group II transition metals, manganese, copper and zinc, wherein the oxygen absorption rate is the same. And a packaging material comprising a combination of an oxygen-absorbing composition and an oxygen-barrier material,
Or, the sum of the product of the amount of oxygen per day that permeates the inside of the package from the outside and the number of days to store and the initial amount of oxygen in the package is the oxygen content in the package. The present invention relates to a method for storing a molded article, wherein the oxygen absorption capacity of the absorbent composition is 80% or less.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below. The oxygen-absorbing polyamide resin composition, which is the material constituting the molded article stored in the present invention, has
A polyamide resin composition containing one or more metal atoms selected from Group VIII transition metals, manganese, copper and zinc.

Polyamides constituting the oxygen-absorbing polyamide resin composition are nylon 6, nylon 66, nylon 666, nylon 610, nylon 6T, nylon MX.
D6 and the like can be mentioned, and among them, nylon MXD
Polyamide containing 6 as a main component is excellent in oxygen absorption capacity.
Nylon MXD6 is obtained by polycondensing a diamine component containing metaxylylenediamine as a main component and a dicarboxylic acid component containing adipic acid as a main component, and other components include paraxylylenediamine, 1 , 3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, tetramethylenediamine, hexamethylenediamine, nonamethylenediamine,
2-methyl-1,5-pentanediamine, suberic acid,
Azelaic acid, sebacic acid, 1,10-decanedicarboxylic acid, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid and the like may be copolymerized. Here, the diamine component preferably contains metaxylylenediamine in an amount of 70 mol% or more, and the dicarboxylic acid component preferably contains adipic acid in an amount of 50 mol% or more.

The polyamide constituting the oxygen-absorbing polyamide resin composition may be a blend of other thermoplastic resins as long as it contains nylon MXD6. For example, nylon 6, nylon 66, nylon 66.
6, polyamide such as nylon 610 and nylon 6T, polyester such as polyethylene terephthalate and polybutylene terephthalate, polyolefin such as polyethylene and polypropylene, polycarbonate, polystyrene,
Examples thereof include polymers such as thermoplastic elastomers. Further, in the present invention, the oxygen-absorbing polyamide resin composition, in the range that does not impair the effects of the present invention, pigments, dyes, lubricants, matting agents, heat stabilizers, weathering stabilizers, ultraviolet absorbers, nucleating agents, Plasticizers, flame retardants, antistatic agents, anti-coloring agents, additives such as anti-gelling agents, clay, mica, glass fibers, it is also possible to add fillers such as zeolite, but is not limited to those shown above. Various materials can be mixed without.

The metal atom contained in the oxygen-absorbing polyamide resin composition is at least one metal atom selected from the group VIII transition metals of the Periodic Table of the Elements, manganese, copper and zinc, and the oxidation reaction of polyamide Promotes the oxygen absorption function of polyamide. Oxidation of polyamide caused by a metal atom includes generation of a radical due to abstraction of a hydrogen atom from a methylene chain adjacent to the arylene group of the polyamide by the metal atom, generation of a peroxy radical by addition of an oxygen molecule to the radical, and generation of a peroxy radical. It is considered to be caused by the abstraction of hydrogen atoms by oxy radicals and each of the above reactions.

A compound containing a metal atom (hereinafter referred to as a metal catalyst compound) is preferably used to add and mix the metal atom to the above-mentioned polyamide. The metal catalyst compound is used in the form of an inorganic acid salt, organic acid salt or complex salt having a low valence number of the above-mentioned metal atom. Examples of the inorganic acid salt include halides such as chlorides and bromides, sulfates, nitrates, phosphates and silicates. On the other hand, examples of the organic acid salts include carboxylates, sulfonates, phosphonates and the like. Further, a transition metal complex with β-diketone or β-keto acid ester and the like can also be used. In particular, in the present invention, it is preferable to use a carboxylate, a halide or an acetylacetonate complex containing the above metal atom since it has a good oxygen absorption function, and more preferably a stearate, an acetate or an acetylacetonate. It is a complex. In the present invention, one or more of the above metal catalyst compounds can be added to the oxygen-absorbing polyamide resin composition, but those containing a cobalt metal atom are particularly excellent in oxygen absorbing function and are preferably used.

The concentration of the metal atom contained in the oxygen-absorbing polyamide resin composition is not particularly limited, but is preferably in the range of 100 to 10,000 ppm. The above metal atom is 1
When the amount is less than 00 ppm, the molded article using the oxygen-absorbing polyamide resin composition often lacks the oxygen-absorbing function, and its storage effect is small even when the present invention is applied. On the other hand, if it is more than 10,000 ppm, oxidative deterioration of the polyamide may occur in the production process of the oxygen-absorbing polyamide resin composition, which is not preferable.

The oxygen-absorbing polyamide resin composition can be produced by melt-mixing the above-mentioned polyamide and metal catalyst compound using an extruder, or by mixing the metal catalyst compound with a solvent to form a solution or slurry. After that, a known method such as a method of mixing with a polyamide and then removing a solvent to adhere to the polyamide can be used. Among these, it is possible to uniformly mix the metal catalyst compound into the polyamide. A preferable method is to melt-mix the polyamide and the metal catalyst compound using a melt-kneading device such as an extruder.

The oxygen-absorbing polyamide resin composition generally has no difference in molding processability from those containing no metal catalyst compound, and can be processed into molded products represented by various packaging materials and packaging containers. As a packaging material, it can be processed into a film-shaped or sheet-shaped molded body, and as a packaging container, at least a part of various pouches such as bottles, trays, cups, tubes, flat bags and standing pouches is configured. It can be used as a material. Furthermore, the structure of the above-mentioned molded article may be a single layer made of the oxygen-absorbing polyamide resin composition, or may be a multi-layered structure in combination with another thermoplastic resin. The oxygen-absorbing polyamide resin composition is a polyamide represented by nylon 6 or nylon 66, a polyester represented by polyethylene terephthalate or polybutylene terephthalate, or a polyolefin represented by polyethylene or polypropylene in order to improve its properties. It can also be used as a mixture with various thermoplastic resins such as polystyrene, polycarbonate, ethylene vinyl alcohol copolymer and the like. In the molded article using the oxygen-absorbing polyamide resin composition, the thickness of the layer using the polyamide is not particularly limited, but the layer may be formed to have a thickness of 1 μm or more. preferable.

As a method for producing a molded article using the oxygen-absorbing polyamide resin composition, a known method can be used. For example, a film, a sheet, or a tubular packaging material can be formed by extruding an oxygen-absorbing polyamide resin composition melted through a T-die, a circular die or the like from an attached extruder. The film-shaped molded product obtained by the above-mentioned method can be stretched to be processed into a stretched film. A bottle-shaped molded article can be obtained by injecting a molten oxygen-absorbing polyamide resin composition into a mold from an injection molding machine to produce a preform, followed by heating to a stretching temperature and blow stretching. . Also, containers such as trays and cups can be obtained by injection molding the molten polyamide in a mold to produce the polyamide, or by molding a sheet-like packaging material by a molding method such as vacuum molding or pressure molding. be able to. Molded articles using the oxygen-absorbing polyamide resin composition can be manufactured by various methods, not by the above-mentioned manufacturing method.

A method of storing a molded article using the oxygen-absorbing polyamide resin composition of the present invention is a method of combining a molded article using the oxygen-absorbing polyamide resin composition with an oxygen-absorbing composition and an oxygen barrier material. It is to be stored in the packaging material and packaging container. The oxygen-absorbing composition referred to in the present invention has an oxygen-absorbing rate superior to that of the oxygen-absorbing polyamide resin composition to be stored, and absorbs oxygen remaining in the storage container and enters from the outside of the storage container. It also has the ability to absorb oxygen. As the oxygen absorbing composition, an oxygen absorbing composition comprising a combination of an oxidizable main agent and an auxiliary agent is preferably used. As the main agent, metal powder, sulfite, dithionite, ascorbic acid or its salt, ascorbic acid ester and the like are used, and among them, metal powder is preferable and iron powder is particularly preferably used. Further, as the auxiliary agent, a chemical substance that promotes the oxygen absorption reaction of the main agent is used.

In the case of using iron powder as the main component, any substance capable of causing an oxygen absorption reaction can be used without any particular limitation on the purity of iron and the like. For example, a part of the surface may be already oxidized, It may also contain the above metal. Also,
The iron powder is preferably granular, and examples thereof include reduced iron powder, atomized iron powder, iron powder such as electrolytic iron powder, and crushed products of various irons such as cast iron and steel and grinding products. Average particle size of iron powder 1-500
μm is preferable, and 3 to 200 μm is particularly preferable.

In the case of an oxygen-absorbing composition containing iron powder as a main component, a metal halide is used as an auxiliary agent. The metal halide has a catalytic effect on the oxygen absorption reaction of the main agent. As the metal halide, for example, chlorides, bromides, and iodides of alkali metals or alkaline earth metals are used, and chlorides, iodides of lithium, sodium, potassium, magnesium, calcium, or barium are preferably used. Compounding amount of metal halide is iron powder 1
It is preferably 0.1 to 20 parts by weight, more preferably 0.1 to 5 parts by weight, per 00 parts by weight.

When the metal halide is used as an auxiliary agent for the oxygen-absorbing composition containing iron powder as a main component, it is preferable to mix it in advance. For example, a method of mixing the metal halide and the iron powder using a ball mill, a speed mill, etc., a method of embedding the metal halide in the uneven portion of the iron powder surface, a method of attaching the metal halide to the iron powder surface using a binder. Alternatively, a method in which an aqueous metal halide solution and iron powder are mixed and then dried to attach the metal halide to the surface of the iron powder can be used. This makes it possible to prevent the iron powder from being easily attached and separated. A preferred oxygen-absorbing composition is an iron powder-based composition containing iron powder and a metal halide, and particularly preferably a metal halide-coated iron powder composition obtained by adhering a metal halide to iron powder.

In the oxygen-absorbing composition used in the present invention, if necessary, an alkaline earth metal oxide, a silane or titanate dispersant, a filler such as clay, mica, silica or calcium carbonate, An adsorbent such as activated carbon or zeolite can be added.

In the present invention, when the above oxygen-absorbing composition is used, the oxygen-absorbing composition is enclosed in a breathable packaging material, or the oxygen-absorbing composition is melted with a thermoplastic resin. A mixture obtained by mixing and dispersing it in a thermoplastic resin, or a stretched product thereof is cut into an appropriate size and enclosed in a breathable packaging material, or an oxygen-absorbing composition is formed into a thermoplastic resin. The one dispersed therein can be used as an intermediate layer constituting the wall of the storage container. As the air-permeable packaging material, a material using paper such as a non-woven fabric or a film having fine holes with a size that allows oxygen to pass therethrough and does not spill the oxygen-absorbing composition to be encapsulated inside is used. Some of them are used. In the present invention, any one can be used without limitation as long as it has an oxygen absorption rate superior to that of the molded article to be stored, and a combination of the above may be used.

When the packaging material and packaging container used in the present invention are filled with the oxygen-absorbing polyamide resin composition and the container is sealed, the oxygen-absorbing composition and the oxygen-absorbing polyamide resin composition are used from that point onward. The oxygen absorption of the molded product is competitively started. In the present invention, the oxygen-absorbing composition, regardless of its form, has a better oxygen-absorbing rate than a molded article using the oxygen-absorbing polyamide resin composition to be stored, but compared with the molded article. It is preferable that the oxygen absorption rate is 2 times or more, and more preferably 3 times or more. When the oxygen absorption rate of the oxygen-absorbing composition is less than twice that of the molded article using the oxygen-absorbing polyamide resin composition to be stored, the oxygen-absorbing composition and the oxygen-absorbing rate of the molded article that occur competitively Is too small,
This is not preferable because the oxygen absorption capacity of the molded product is greatly reduced. Here, the oxygen absorption rates of the oxygen-absorbing composition and the molded article to be stored are compared in one packaging unit as a whole. That is, the oxygen absorption rate (ml / day) with respect to the total amount of the oxygen absorbing composition and the molded article in one packaging unit is compared.
For molded products, the oxygen absorption rate in the packaged state. For example, in the case of a film roll, the oxygen absorption rate measured in the roll state is used. On the other hand, in the case of bottles, trays, etc., the oxygen absorption rate per bottle (ml / day)
・ Oxygen absorption rate (ml)
/ Day).

The packaging material and packaging container used in the present invention are made of a material having a high oxygen barrier property, which is capable of reducing the invasion of oxygen from the outside, in at least a part of the materials constituting the packaging material and the packaging container. is there. As a material having a high oxygen barrier property, for example, an ethylene-vinyl alcohol copolymer resin, an oxygen barrier thermoplastic resin typified by polymethaxylylene adipamide, a vinylidene chloride coating film, an aluminum vapor deposition film, or a silica vapor deposition Examples of the material that enhances the oxygen barrier property include a metal such as a thermoplastic resin film or an aluminum foil which is coated or vapor-deposited with a material having an oxygen barrier property represented by a film or the like. Among these, those using metals such as aluminum foil have almost zero oxygen permeation amount and are also excellent in moisture resistance, so that oxygen absorption of molded articles using oxygen absorbing polyamide resin composition for a long period of time It is preferably used because the ability can be retained.

The shape of the packaging material and the packaging container may be a bag shape, a box shape, or a can shape. The bag-shaped one uses a film having a multi-layer structure in which the above-mentioned oxygen barrier material is laminated with another thermoplastic resin, and the box-shaped one is a structure in which the oxygen barrier material is laminated on a paper base material. And a can-shaped one having a galvanized or resin-coated metal inner surface, preferably equipped with a device capable of degassing or gas replacement, and an oxygen-absorbing composition, or oxygen. It may be used by enclosing a combination of a mixture of an absorbent composition and a thermoplastic resin enclosed in a breathable packaging material together with a molded article using an oxygen-absorbing polyamide resin composition, or by sticking to a container wall. it can. Furthermore, the oxygen-absorbing resin composition obtained by kneading the oxygen-absorbing composition with a thermoplastic resin may be laminated or used as an intermediate layer forming a container wall. As for the oxygen-absorbing composition that constitutes the storage container, the one using a mixture of the oxygen-absorbing composition and the thermoplastic resin is formed by using the oxygen-absorbing polyamide resin composition due to the breakage of the breathable packaging material. The product is preferably used because it can prevent the product from being contaminated with the oxygen-absorbing composition.

In the present invention, the oxygen permeation amount of the packaging container excluding the oxygen absorbing composition is preferably 20 ml / day or less in an atmosphere of a temperature of 23 ° C. and a relative humidity of 50%, preferably 10 ml / day. It is more preferable if it is not more than day. When the oxygen permeation rate is higher than 20 ml / day, a large amount of the oxygen-absorbing composition may be required or the oxygen concentration in the container may not be kept low for a long time, which is not preferable. Further, the oxygen permeation amount of the packaging material itself excluding the oxygen absorbing composition is such that the temperature is 23 ° C. and the relative humidity is 5%.
It is preferably 30 ml / day · m ² or less in a 0% atmosphere, and more preferably 25 ml / day · m ² or less. When the oxygen permeation amount is higher than 30 ml / day · m ^2, it is not preferable because a large amount of the oxygen-absorbing composition may be required or the oxygen concentration in the container may not be kept low for a long period of time.

In the present invention, when a molded article using the oxygen-absorbing polyamide resin composition is stored using the above-mentioned packaging material or packaging container, the permeation per day permeated from the outside into the packaging body The sum of the product of the amount of oxygen (ml / day) and the number of days of storage and the initial amount of oxygen (ml) in the package is the oxygen absorption capacity (m) of the oxygen-absorbing composition in the package.
It is necessary to keep it sealed so that it is smaller than l), preferably 80% or less, more preferably 70% or less.
% Or less. The sum of the initial amount of oxygen in the package and the product of the amount of oxygen per day that penetrates into the package from the outside and the number of storage days is 80% of the oxygen absorption capacity of the oxygen absorbing composition.
When it is higher than 0.1%, the oxygen absorbing rate of the oxygen absorbing composition tends to decrease as the oxygen absorbing capacity approaches a saturated state, and the oxygen absorbing capacity of the molded article during storage may be impaired in some cases. Therefore, it is not preferable.

When storing a molded article using the oxygen-absorbing polyamide resin composition in a packaging material or a packaging container, put as many molded articles as possible into the packaging material or the packaging container, and It is preferable to reduce the amount of initial oxygen in the packaging container. If the packaging material or packaging container is a flexible container such as a bag, remove air as much as possible and then heat seal it, or use a deaerator to remove air and then heat seal it. Alternatively, a method in which an inert gas such as nitrogen is circulated in the bag and then heat-sealed is preferably performed. Also, in the case of a rigid container such as a metal can, a method in which an inert gas such as nitrogen is circulated in the bag and then sealed, or a pipe is attached to the lid, and air is removed from this pipe by using a deaerator or the like. The method of sealing after removing is preferably performed.

When measuring the oxygen concentration in the packaging material or the packaging container, for example, the gas inside the packaging material or the packaging container is sampled with a syringe before or after sealing, and then gas chromatography or an oxygen concentration meter is used. The method of measuring is mentioned.

[0030]

The present invention will be described in more detail below. However, the present invention is not limited to the following examples.
The evaluation methods used in the examples and comparative examples are as follows. (1) Measurement of oxygen absorption capacity of molded product Put one molded product in a four-sided sealed bag laminated with aluminum foil,
The bag was sealed by heat sealing so that the air in the bag became 1000 ml, and stored in a constant temperature bath at 40 ° C. until the oxygen concentration in the bag did not change. After that, the gas in the storage container was sampled using a syringe, the residual oxygen concentration in the bag was measured with a Toray Co., zirconia oxygen analyzer,
The oxygen absorption capacity per molded product was calculated. When the molded product was a roll film, the film in the outer peripheral portion was sampled and the oxygen absorption capacity was determined by the above method.

Example 1 Polyamide obtained by melt polycondensation of adipic acid and metaxylylenediamine, and cobalt metal concentration of 4000 ppm
After mixing the cobalt stearate weighed so that it would be A pellet of 0.5 mmL × 2.5 mmφ was prepared. Next, a layer of polyethylene (50 μm) / adhesive resin (10 μm) / oxygen-absorbing polyamide resin layer (20 μm) / adhesive resin (10 μm) / polyethylene (50 μm) using a 3 type 5-layer multilayer film manufacturing apparatus A multilayer film having a configuration and a width of 30 cm and a length of 100 m was produced, and wound into a roll on a vinyl chloride tube having an inner diameter of 75 mmφ. This multilayer film was cut into 30 cm x 30 cm, placed in an aluminum foil laminated bag, sealed with heat seal at an air volume of 2000 ml at 40 ° C.
As a result of examining the oxygen absorption capacity after storage at 120 ° C., it was confirmed that it had an oxygen absorption capacity of 120 ml. Next, an oxygen absorbing agent in which an oxygen absorbing composition having a mixture of 1 g of calcium chloride and 25 g of granular iron powder having an average particle diameter of 120 μm and an oxygen absorbing capacity of 6250 ml is enclosed in a packaging material made of a polyethylene film having fine pores. And the above film roll with PET (12 μm) / aluminum foil (9 μ
m) / polyethylene (30 μm) layered aluminum foil laminated film was wrapped, and an adhesive tape using aluminum foil was attached to the end of the film to prevent oxygen from leaking inside the package. The amount of air inside the package is calculated 1
The amount of oxygen was 325 ml and the amount of oxygen was 276 ml. The amount of oxygen permeated into the inside of the package was substantially 0 ml. After storing this package at room temperature for 6 months, the package was opened and the oxygen absorption capacity of the multilayer film was measured in the same manner as described above. As a result, the oxygen absorption capacity was 120 ml. It was confirmed that the absorption capacity was completely maintained.

Example 2 Using a pellet made of the oxygen-absorbing polyamide resin composition obtained in Example 1 and a 3-kind 5-layer multi-layer film manufacturing apparatus,
Polypropylene (50 μm) / Adhesive resin (10 μm)
A multilayer film having a layer structure of / oxygen-absorbing polyamide resin layer (30 μm) / adhesive resin (10 μm) / polypropylene (30 μm) was prepared, and the polypropylene (30 μm) side of the film was subjected to corona discharge treatment. Then, using a laminator, the corona discharge treated surface of the above film and the aluminum foil surface of the film made of PET (12 μm) / aluminum foil (9 μm) were dry laminated with a urethane adhesive to obtain polypropylene (50 μm) / Adhesive resin (10 μm) / oxygen absorbing polyamide resin layer (30
μm) / Adhesive resin (10 μm) / Polypropylene (3
A multilayer film having a layer structure of 0 μm) / aluminum foil (9 μm) / PET (12 μm) was produced. Then, a standing pouch having a length of 18 cm and a width of 11 cm was manufactured from this film. As a result of investigating the oxygen absorption capacity of one standing pouch, it was confirmed that it had an oxygen absorption capacity of 35 ml. Next, the above-mentioned 300 standing pouches and the oxygen absorbent obtained in Example 1 were treated with polyethylene (50 μm) having an oxygen permeation amount of 2.5 ml per day.
/ Vinylidene chloride-coated nylon 6 (15 μm) was placed in a bag using a multilayer film having a layer structure, and heat-sealed while removing air as much as possible and hermetically sealed. The amount of air in the bag was about 500 ml and the amount of oxygen was 104 ml. After this was stored at room temperature for 6 months, the oxygen absorption capacity of the standing pouch was measured in the same manner as the above-mentioned method, and it was found to be 35 ml of oxygen absorption capacity, and the oxygen absorption capacity immediately after production was maintained. It was confirmed.

Example 3 Polyethylene (40 μm) / Adhesive resin (10 μm) /
Ethylene-vinyl alcohol copolymer resin (15 μm) /
Adhesive resin (10 μm) / oxygen absorbing resin layer (50 μm
The film roll was preserved in the same manner as in Example 1 except that a packaging film made of an oxygen-absorbing film having a layer structure of m) / polyethylene (40 μm) was used and the oxygen absorbent was not enclosed. . The oxygen-absorbing resin layer that constitutes the oxygen-absorbing film is polyethylene 1
5 parts by weight of calcium chloride and 35 parts by weight of granular iron powder having an average particle size of 30 μm are mixed with 00 parts by weight of an oxygen-absorbing resin composition, which absorbs oxygen in a portion necessary for packing a film roll. The capacity was 1400 ml. Regarding the above-mentioned oxygen-absorbing film, a film (polyethylene (40 μm
m) / adhesive resin (10 μm) / ethylene-vinyl alcohol copolymer resin (15 μm) / adhesive resin (10 μm
m) / polyethylene (50 μm) / polyethylene (40
The amount of oxygen permeation per day of the portion required for packaging the film roll of (μm)) was 0.4 ml. After storing the above-mentioned package at room temperature for 6 months, the package was opened and the oxygen absorption capacity of the multilayer film was measured in the same manner as the above-mentioned method. As a result, the oxygen absorption capacity was 120 ml. It has been confirmed that

Comparative Example 1 A roll was stored in the same manner as in Example 1 except that a polyethylene film having a thickness of 60 μm was used. In addition,
The oxygen permeation amount per day of the portion required for packaging the film roll was 100 ml. The oxygen absorption capacity of the film after being stored at room temperature for 6 months was measured and found to be 85 ml / g, which was about 29% lower than the oxygen absorption capacity immediately after production.

Table 1 Example 1 Example 2 Example 3 Comparative Example 1 Packaging material for molded product Aluminum foil laminate KON Oxygen absorbing polyethylene film Film film Film Oxygen absorption capacity of molded product 120 35 120 120 (ml) Inside package Initial oxygen amount 276 104 276 276 (ml) Oxygen permeation amount in the package 0 2.5 0.4 ^{* 1} 100 (ml / day) Package for 6 months 276 554 348 ^{* 2} 18276 Calculated oxygen amount (ml) ^a) Oxygen absorber 6250 6250 1400 6250 Oxygen absorption capacity (ml) Molded article after storage for 6 months 120 35 120 85 Oxygen absorption capacity (ml) a) Package oxygen content for 6 months = Calculated in container Initial oxygen amount + (oxygen permeation amount of storage container x 180) * 1. Oxygen permeation amount when there is no oxygen absorbing composition * 2. Oxygen absorption capacity of storage container with intermediate layer made of oxygen absorbing composition

[0036]

The method for storing a molded article using the oxygen-absorbing polyamide resin composition of the present invention is capable of retaining the oxygen-absorbing capacity immediately after production for a long period of time, has a high commercial value, and is industrially used. It is excellent.

Continued front page    F-term (reference) 3E067 AB99 BA04A BA05A BA12A                       BB06B BB11C BB12B BB14B                       BB14C BB22B BB22C BB25B                       BB25C BB26B BB26C CA03                       CA04 CA05 CA24 EA06 EE25                       EE28 GA15 GA19 GB04 GB13                       GD10                 4F071 AA55 AB06 AB07 AB10 AF08                       AH04 BA01 BB06 BC01                 4J002 CL001 DA066 DA076 DA106                       GG02

Claims (8)

[Claims] 1. A method for storing a molded article using an oxygen-absorbing polyamide resin composition containing at least one metal atom selected from transition metals of Group VIII of the Periodic Table of Elements, manganese, copper and zinc. And the oxygen absorption rate is 2 times that of the molded product.
The amount of oxygen per day that packs a molded article using a packaging material and / or a packaging container that is a combination of an oxygen-absorbing composition and an oxygen-barrier material that is more than double and that permeates from the outside into the packaging body. The method of storing a molded article, wherein the sum of the product of the number of days to be stored and the initial amount of oxygen in the package is 80% or less of the oxygen absorption capacity of the oxygen-absorbing composition in the package. 2. The packaging material and / or packaging container comprises:
The method for storing a molded article according to claim 1, wherein the oxygen-absorbing composition is enclosed in a breathable packaging material, and an oxygen-barrier material is used. 3. The packaging material and / or packaging container comprises:
The method for preserving a molded article according to claim 1, wherein a mixture of an oxygen-absorbing composition and a thermoplastic resin is enclosed in a breathable packaging material, and an oxygen-barrier material is used. 4. The packaging material and / or packaging container comprises:
The method for storing a molded article according to claim 1, wherein a laminate having a thermoplastic resin containing an oxygen-absorbing composition disposed in an intermediate layer is used at least in part. 5. The packaging container, excluding the oxygen-absorbing composition, has an oxygen permeation amount of 20 at 23 ° C. and an atmosphere of 50%.
The method for storing a molded article according to claim 1, wherein the storage rate is not more than ml / day. 6. The packaging material, excluding the oxygen-absorbing composition, has an oxygen permeation amount of 30 at 23 ° C. and an atmosphere of 50%.
The method for storing a molded article according to claim 1, wherein the volume is less than or equal to ml / day · m ² . 7. The molded product is a film-shaped or sheet-shaped molded product, a container or an injection-molded product obtained by processing the film-shaped or sheet-shaped molded product, and a container obtained by processing the injection-molded product. The method for storing a molded article according to claim 1, which is any one of the following: 8. The oxygen-absorbing polyamide resin composition,
The method for storing a molded article according to claim 1, which comprises a polyamide obtained by polycondensing a diamine component containing 70 mol% or more of metaxylylenediamine and a dicarboxylic acid component containing 50 mol% or more of adipic acid.