JP2002240813A - Oxygen-absorbing container excellent in storability as empty container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxygen-absorbing container whose oxygen absorbing performance can be kept for a long time even when an empty container is preserved in the air. SOLUTION: The oxygen-absorbing container includes, as an intermediate layer, an oxygen-absorbing resin layer containing an oxidizing polymer and a transition-metal-based oxidation catalyst. The oxygen-absorbing resin layer is sandwiched by an oxygen barrier resin and/or an oxygen barrier deposit layer to provide the oxygen-absorbing container which is excellent in storability as an empty container.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxygen-absorbing container excellent in storage stability in an empty container.

[0002]

2. Description of the Related Art Conventionally, metal cans, glass bottles, various plastic containers and the like have been used as packaging containers.
Deterioration of contents and reduction in flavor due to oxygen remaining in the container and oxygen permeating the container wall have become problems.

[0003] In particular, in a metal can or a glass bottle, oxygen permeation through the container wall is zero, and only oxygen remaining in the container is a problem, whereas in a plastic container, oxygen permeation through the container wall is zero. It occurs in orders that cannot be ignored and poses a problem in the preservability of the contents.

In order to prevent this, in a plastic container, the container wall has a multilayer structure, and at least one of the layers is made of an oxygen-permeable resin such as an ethylene-vinyl alcohol copolymer. I have.

[0005] An oxygen absorber has been used for a long time to remove oxygen in a container. An example of applying the oxygen absorber to the container wall is disclosed in Japanese Patent Publication No. 62-1824. According to the above, a layer formed by mixing a deoxygenating agent mainly composed of a reducing substance such as iron powder with an oxygen-permeable resin and a layer having an oxygen gas barrier property are laminated to form a multilayer structure for packaging. And

Japanese Patent Application Laid-Open No. 1-278 according to the proposal of the present inventors.
No. 344 discloses that the oxygen permeability coefficient at 20 ° C. and 0% RH is ^10-12 cc · cm / cm ² · sec · cmHg or less and 20
A resin composition obtained by blending an organometallic complex of a transition metal with a gas-barrier thermoplastic resin having a water adsorption of 0.5% or more at 100 ° C. and 100% RH is used as an intermediate layer, and moisture resistance is provided on both sides of the intermediate layer. A plastic multilayer container characterized by a laminated structure provided with a layer of a plastic resin is described.

JP-A-2-500846 discloses a metal-catalyzed oxidation of an oxidizable organic component in a composition comprising a polymer and having oxygen-scavenging properties or a packaging barrier containing a layer of the composition. Describes the use of a barrier for packaging characterized by capturing oxygen by using a polyamide, particularly a xylylene group-containing polyamide as the oxidizable organic component.

[0008]

The method in which an oxygen absorbent such as iron powder is blended with a resin and used for a container wall of a packaging material is satisfactory in that oxygen absorption performance is large. There is a limitation in application that it cannot be used in the field of packaging that requires transparency because of coloring to a specific hue.

On the other hand, the oxygen-absorbing resin composition containing the transition metal catalyst has an advantage that it can be applied to a substantially transparent packaging container, but when stored in an empty container, it takes about three months. It has been found that there is a disadvantage that the oxygen absorption performance is lost by the preservation.

Accordingly, an object of the present invention is to provide an oxygen-absorbing container capable of maintaining oxygen absorbing performance for a long period of time even when stored in an empty container in air.

[0011]

According to the present invention, there is provided an oxygen-absorbing container comprising, as an intermediate layer, an oxygen-absorbing resin layer containing an oxidizing polymer and a transition metal-based oxidation catalyst.
An oxygen-absorbing container excellent in storability in an empty container, wherein the oxygen-absorbing resin layer is sandwiched by an oxygen-barrier resin and / or an oxygen-barrier vapor-deposited layer is provided. In the oxygen-absorbing container of the present invention, the oxygen-barrier resin is preferably an ethylene-vinyl alcohol copolymer or a polyamide derived from a xylylene group-containing diamine and an aliphatic dicarboxylic acid.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Operation] The oxygen-absorbing container of the present invention comprises an oxygen-absorbing resin layer containing an oxidizing polymer and a transition metal-based oxidation catalyst as an intermediate layer. It is characterized by sandwiching the reactive resin layer with an oxygen-barrier resin, particularly an ethylene-vinyl alcohol copolymer or an oxygen-barrier vapor-deposited layer, and can enhance the preservability of oxygen absorption in an empty container.

See the examples below. In the case of a container (plastic bottle having a capacity of 1,000 ml) using a polyamide resin mixed with a cobalt-based oxidation catalyst as an oxygen-absorbing intermediate layer, the initial oxygen absorption rate is 0.228.
When stored in air for 3 months, the oxygen absorption rate is 0.108 cc / day.
(Retention rate of oxygen absorption rate: 47%).

On the other hand, when the oxygen-absorbing intermediate layer is sandwiched by a layer of ethylene vinyl alcohol copolymer, the initial oxygen absorption rate is 0.114 cc / day.
The oxygen absorption rate is maintained at a value of 0.114 cc / day even after storage in the air for 3 months (the oxygen absorption rate retention rate is 100%). It can be seen that the container of the present invention has excellent oxygen-absorbing preservability.

In the present invention, when the oxygen-absorbing intermediate layer is sandwiched with an oxygen-barrier resin such as ethylene vinyl alcohol copolymer, several advantages are achieved in addition to maintaining oxygen absorption in an empty container. . In other words, oxygen absorption by the oxygen-absorbing intermediate layer is activated by the presence of moisture, but the oxygen-barrier resin provided inside the container of the oxygen-absorbing intermediate layer absorbs moisture in the contents, and absorbs oxygen. Activates the neutral interlayer and helps absorb oxygen in the container. On the other hand, the oxygen-barrier resin provided on the outside of the container of the oxygen-absorbing intermediate layer suppresses the permeation of oxygen from the outside of the container, and brings about an effect that oxygen absorption by the intermediate layer is effectively used for absorbing oxygen in the container. . The same applies to the case where an oxygen-barrier vapor deposition layer is provided instead of the oxygen-barrier resin.

[Layer Structure of Container] In FIG. 1 showing the cross-sectional structure of the oxygen-absorbing container of the present invention, the container 1 has an oxygen-absorbing resin layer 2 containing an oxidizing polymer and a transition metal-based oxidation catalyst. The oxygen-absorbing resin layer 2 is sandwiched between layers 3a and 3b of an oxygen-barrier resin, particularly an ethylene-vinyl alcohol copolymer. A moisture resistant resin inner layer 4 and a moisture resistant resin outer layer 5 are provided outside the oxygen barrier resin layers 3a and 3b.

Although not shown in FIG. 1, between the oxygen-absorbing resin layer 2 and the oxygen-barrier resin layers 3a and 3b, and between the oxygen-absorbing resin layers 3a and 3b and the moisture-resistant resin inner layer 4
If there is no adhesiveness between the two and the moisture-resistant resin outer layer 5, an adhesive resin layer known per se can be interposed.

[Oxygen-absorbing resin layer] As the oxygen-absorbing resin layer, a resin composition containing an oxidizing resin and a transition metal catalyst is used.

The oxidizing resin is a resin which is oxidized by oxygen in the air by the action of a transition metal catalyst, (i) a resin containing a carbon side chain, (ii) a polyamide resin containing a xylylene group, (Iii) Ethylenically unsaturated group-containing polymers and the like are used. Hereinafter, this example will be described.

Oxygen absorption in a composition containing a transition metal-based catalyst and a resin is carried out via oxidation of the resin, and the oxidation is carried out by hydrogen atoms from activated carbon atoms by the transition metal-based catalyst. Generation of radicals by extraction of
It is believed that peroxy radicals are generated by the addition of oxygen molecules to the radicals, and hydrogen atoms are abstracted by the peroxy radicals. The above-mentioned polymer has such an activated carbon atom and is used as an oxidizable resin.

Specific examples of the resin (i) having a carbon side chain include (a) a modified or unmodified olefin resin,
(B) Branched-chain aliphatic dicarboxylic acids, aliphatic diols, aliphatic oxycarboxylic acids or branched-chain thermoplastic polyesters derived from their lactones, particularly aliphatic polyesters, (c) Branched-chain fats And the like. Examples thereof include aliphatic dicarboxylic acids, aliphatic diamines, aliphatic aminocarboxylic acids, and branched chain-containing thermoplastic polyamides derived from lactams thereof, particularly aliphatic polyamides. Less than,
An example will be described.

(A) Olefin resin: In the carbon-carbon main chain of the resin, hydrogen atoms can be easily extracted,
Thus, the position where the radical is easily generated is considered to be the position of the tertiary carbon atom to which the carbon side chain is bonded. Polyethylene, for example low density, medium density or high density polyethylene, has a long branched chain that can absorb oxygen at the tertiary carbon atom with the branched chain. Further, in a polymer or copolymer of an α-olefin derived from an α-olefin having 3 or more carbon atoms, since a large number of tertiary carbon atoms are present in the molecule, active absorption of oxygen occurs.
preferable.

The α-olefin used to introduce a branched chain into the olefin-based resin may have 3 to 2 carbon atoms.
Α-olefins of 0 are suitable, specifically propylene, 1-butene, 4-methyl-1-pentene, 1-hexene,
1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene,
1-pentadecene, 1-hexadecene, 1-heptadecene, 1-
Nonadecene, 1-eicosene, 9-methyl-1-decene, 11-
Methyl-1-dodecene, 12-ethyl-1-tetradecene and the like.

As specific resins, homopolypropylene, block copolymer or random copolymer type polypropylene, linear low density polyethylene, ethylene-propylene copolymer, polybutene-1, ethylene-butene-
1 copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer and the like.

Further, at least one functional group (b) selected from the group consisting of a carboxylic acid group, a carboxylic acid anhydride group, a carboxylic acid ester group, a carboxylic acid amide group and a carbonyl group is introduced into the olefin resin. The modified olefin-based resin is also used, and the monomers used for this modification include the above-mentioned ethylenically unsaturated monomers having the functional group (b) and carbon monoxide.

As these monomers, it is desirable to use unsaturated carboxylic acids or derivatives thereof. Specifically, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid Α, β-unsaturated carboxylic acids such as acids, bicyclo [2,2,
1] unsaturated carboxylic acids such as hept-2-ene-5,6-dicarboxylic acid, α, β unsaturated carboxylic anhydrides such as maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo [2,2,1] Unsaturated carboxylic acid anhydrides such as hept-2-ene-5,6-dicarboxylic anhydride, methyl acrylate, methyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl fumarate Esters of unsaturated carboxylic acids such as dimethyl itaconate, diethyl citraconic acid, dimethyl tetrahydrophthalic anhydride, and dimethyl bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylate. it can. Among them, maleic acid, bicyclo [2,2,1] hept-2-ene-5,6-dicarboxylic acid or anhydrides thereof are preferable.

The olefin resin is modified by using an olefin resin having a branched carbon chain as a base polymer and graft-copolymerizing the base polymer with an unsaturated carboxylic acid or a derivative thereof by a known means. However, it can also be produced by random copolymerization of the above-mentioned α-olefin or polyene with an unsaturated carboxylic acid or a derivative thereof.

The olefin resin has a melt flow rate (MFR, JIS K6760) of 0.1 to 50.
g / 10 min, particularly preferably in the range of 0.2 to 30 g / 10 min, from the viewpoint of workability and mechanical properties.

(B) Branched chain-containing thermoplastic polyester:
Any thermoplastic polyester derived from an acid component having a carbon branched chain, a diol component, a hydroxycarboxylic acid component, or a lactone component can be used as oxygen-absorbing. Suitable aliphatic polyester resins include biodegradable aliphatic polyester resins mainly composed of branched chain-containing hydroxyalkanoate units.

Examples of the branched chain-containing polyhydroxyalkanoate include the following formula (I) In the formula, R is a linear or branched alkyl group, n is a positive integer including zero, and a repeating unit represented by the following formula: for example, lactone lactone [R = CH
₃ , n = 0, LLA], 3-hydroxybutyrate [R
_{= CH 3, n = 1,3HB]} , 3- hydroxyvalerate _{[R = CH 2 CH 3,} n = 1,3HV], 3- hydroxy-caproate _{[R = (CH 2) 2} CH 3, n =
1,3HC], 3-hydroxyheptanoate [R =
_{(CH 2) 3 CH 3,} n = 1,3HH], 3- hydroxyoctanoate _{[R = (CH 2) 4} CH 3 n = 1,3
HO], 3-hydroxynonanoate [R = (CH ₂ )
₅ CH ₃ , n = 1, 3HN]; 3-hydroxydecanoate [R = (CH ₂ ) ₆ CH ₃ , n = 1, 3HD]; .

The polyhydroxyalkanoate may be a homopolymer such as polylactic acid, or a copolymer of 3-hydroxybutyrate and another 3-hydroxyalkanoate, especially 3-hydroxyvalerate. A copolymer may be used.

The aliphatic polyester resin should have at least a molecular weight capable of forming a film, and generally has a number average molecular weight of 50,000 to 12,000.
It is preferably in the range of 0, especially 60,000 to 120,000. The aliphatic polyester preferably has a glass transition point (Tg) of -60 ° C or higher, particularly -30 ° C or higher.

Among these aliphatic polyesters, polylactic acid is mentioned as an industrially produced, easily available and environmentally friendly aliphatic polyester. Polylactic acid (PLLA) is a resin made from cereal starch such as corn, and lactic acid fermentation product of starch, L-
It is a polymer containing lactic acid as a monomer, and is generally produced by ring-opening polymerization of its dimer, lactide. This polymer is decomposed by water and carbon dioxide gas by microorganisms existing in nature, and is attracting attention as a complete recycling system type resin. Also, its glass transition point (Tg)
Also has an advantage of about 58 ° C., which is close to that of PET.

(C) Branched chain-containing thermoplastic polyamide: The polyamide usable as the oxidizing resin is at least a part of aliphatic dicarboxylic acid, aliphatic diamine, aliphatic aminocarboxylic acid or a lactam thereof constituting the polyamide. Having a carbon branched chain. Generally, the polyamide is preferably a polyamide derived from an aliphatic diamine having a branched chain and a dicarboxylic acid component.

As the diamine component having a branched chain, a linear alkylenediamine having 4 to 25 carbon atoms, particularly 6 to 18 carbon atoms, is suitable, and specific examples thereof are 1,4-diamino-1
-Methylbutane, 1,4-diamino-2-methylbutane, 1,4-diamino-1-ethylbutane, 1,4-diamino-1,2-dimethylbutane, 1,4-diamino-1,3-dimethylbutane, 1 1,4-diamino-1,4-dimethylbutane, 1,4-diamino-2,3-dimethylbutane, 1,5-diamino-2-methylpentene, 1,2-diamino-
1-butylethane, 1,6-diamino-2-methylhexane, 1,6
-Diamino-2,5-dimethylhexane, 1,6-diamino-2,4-
Dimethylhexane, 1,6-diamino-3,3-dimethylhexane, 1,6-diamino-2,2-dimethylhexane, 1,6-diamino-2,2,4-trimethylhexane, 1,6-diamino- 2,4,4-trimethylhexane, 1,7-diamino-2-methylheptane,
1,7-diamino-2,4-dimethylheptane, 1,7-diamino-2,
3-dimethylheptane, 1,7-diamino-2,4-dimethylheptane, 1,7-diamino-2,5-dimethylheptane, 1,7-diamino-2,2-dimethylheptane, 1,8-diamino- 2-methyloctane, 1,8-diamino-1,3-dimethyloctane, 1,8-diamino-1,4-dimethyloctane, 1,8-diamino-2,4-dimethyloctane, 1,8-diamino- 3,4-dimethyloctane,
1,8-diamino-4,5-dimethyloctane, 1,8-diamino-2,
2-dimethyloctane, 1,8-diamino-3,3-dimethyloctane, 1,8-diamino-4,4-dimethyloctane, 1,6-diamino-2,4-diethylhexane, 1,9-diamino- 5-methylnonane and the like.

These branched diamines may be used alone or in combination of two or more. Further, other diamine components such as 1,6-diaminohexane, 1,8-diaminooctane,
Linear alkylene diamines having 4 to 25 carbon atoms, particularly 6 to 18 carbon atoms, such as 1,10-diaminodecane and 1,12-diaminododecane, bis (aminomethyl) cyclohexane, bis (4-
Aminocyclohexyl) methane, 4,4'-diamino-3,
3'-dimethyldicyclohexylmethane, especially bis (4-
Alicyclic diamines such as aminocyclohexyl) methane, 1,3-bis (aminocyclohexyl) methane and 1,3-bis (aminomethyl) cyclohexane, and aromatic fats such as m-xylylenediamine and / or p-xylylenediamine Also used in combination with group diamines.

On the other hand, examples of the dicarboxylic acid component include aliphatic dicarboxylic acids having 4 to 15 carbon atoms such as succinic acid, adipic acid, sebacic acid, decanedicarboxylic acid, undecanedicarboxylic acid and dodecanedicarboxylic acid, terephthalic acid and isophthalic acid. And the like.

An aminocarboxylic acid component may be copolymerized with the polyamide. Examples of the aminocarboxylic acid component include aliphatic aminocarboxylic acids such as ω-aminocaproic acid, ω-aminooctanoic acid, ω-amino Examples include undecanoic acid, ω-aminododecanoic acid, and araliphatic aminocarboxylic acids such as para-aminomethylbenzoic acid and para-aminophenylacetic acid.

These polyamide resins also have relative viscosities (η rel) measured at a concentration of 1.0 g / dl in 98% sulfuric acid and a temperature of 20 ° C. of 1.3 to 1.3, because of the mechanical properties of the container and the ease of processing. It is desirable to be in the range of 4.2, especially 1.5 to 3.8.

(Ii) Xylylene group-containing polyamide resin:
It is known that a polyamide derived from a xylylene group-containing polyamide resin, particularly a diamine component mainly composed of xylylenediamine and a dicarboxylic acid component, has an oxidizing property in combination with a transition metal catalyst. Of course, it can also be used. A radical is generated by abstraction of a hydrogen atom from a methylene chain (particularly, a methylene chain adjacent to an arylene group) of the polyamide resin by the transition metal catalyst, and oxidation proceeds by the same reaction mechanism as described above.

As the polyamide resin, a xylylene group-containing polyamide is preferable, and specifically, polymethaxylylene adipamide, polymethaxylylene sebacamide, polymethaxylylene veramide, polyparaxylylene pimeramide, polymer Homopolymers such as taxylyleneazeramid,
And copolymers of meta-xylylene / para-xylylene adipamide copolymer, meta-xylylene / para-xylylene pimeramide copolymer, meta-xylylene / para-xylylene sebacamide copolymer, and meta-xylylene / para-xylylene azeramide copolymer Polymer or components of these homopolymers or copolymers, aliphatic diamines such as hexamethylene diamine, alicyclic diamines such as piperazine, aromatic diamines such as para-bis (2-aminoethyl) benzene, terephthalic acid Aromatic dicarboxylic acids such as lactams such as ε-caprolactam, ω- such as 7-aminoheptanoic acid
Copolymers obtained by copolymerizing an aromatic aminocarboxylic acid such as aminocarboxylic acid and para-aminomethylbenzoic acid, and the like, and a diamine component containing m-xylylenediamine and / or p-xylylenediamine as a main component And a polyamide obtained from an aliphatic dicarboxylic acid and / or an aromatic dicarboxylic acid can be particularly preferably used. These xylylene group-containing polyamides are preferable from the viewpoint of oxygen absorption because radical generation and oxygen absorption (peroxide generation) occur efficiently in the methylene chain adjacent to the benzene ring.

The polyamide resin used in the present invention has a terminal a
Mino group concentration of 10 to 50 eq / 10 ⁶preferably g
More preferably, if the terminal amino group concentration exceeds the above range, oxygen
It is not preferable because the absorption rate is reduced.
Even if the group concentration is too low, there is a limit to the improvement of oxygen absorption rate
is there. Further, the polyamide resin used in the present invention has a terminal resin.
The ratio of ruboxyl group concentration / terminal amino group concentration is 1 to 1
It is preferably in the range of 2, preferably 2 to 11. End
The ratio of carboxyl group concentration / terminal amino group concentration is within the above range
It is not preferable to exceed this value because the oxygen absorption rate is reduced.
On the other hand, even if this ratio is too low,
Has a limit.

The polyamide resin having a terminal amino group concentration or a terminal carboxyl group concentration / terminal amino group concentration within the above range can be selected from commercially available polyamide resins. Generally, the polyamide resin produced by the solid-state polymerization method has a terminal amino group concentration within a lower range than the polyamide resin produced by another polymerization method.
Further, even for a polyamide resin having a terminal amino group concentration exceeding the range specified in the present invention, a predetermined terminal amino group concentration can be obtained by taking measures to reduce the terminal amino group concentration. For example, during the manufacturing process of polyamide,
Alternatively, a terminal amino group can be reduced by performing acylation for blocking the terminal amino group after the production. As the acylating agent used for this purpose,
Examples include acids such as acetic anhydride, acetyl chloride, benzoyl chloride, and toluenesulfonic acid, acid anhydrides, acid halides, and the like, but are not limited to these examples.

These polyamide resins have a relative viscosity (η rel) of from 1.3 to 1.0 g / dl in 98% sulfuric acid and a temperature of 20 ° C. in view of the mechanical properties of the container and the ease of processing. It is desirable to be in the range of 4.2, especially 1.5 to 3.8.

(Iii) Ethylenically unsaturated group-containing polymer:
It is particularly preferable to use a polymer derived from a polyene as the oxidizing polymer. As such a polyene, a resin containing a unit derived from a polyene having 4 to 20 carbon atoms or a chain or cyclic conjugated or non-conjugated polyene is preferably used. These monomers include, for example, conjugated dienes such as butadiene and isoprene; 1,4-hexadiene,
Methyl-1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene, 4,5-dimethyl-1,4-
Chain non-conjugated dienes such as hexadiene and 7-methyl-1,6-octadiene; methyltetrahydroindene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-
Isopropylidene-2-norbornene, 5-vinylidene-2-
Norbornene, 6-chloromethyl-5-isopropenyl-2-
Cyclic non-conjugated dienes such as norbornene and dicyclopentadiene; trienes such as 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene and 2-propenyl-2,2-norbornadiene; Chloroprene and the like.

These polyenes may be incorporated into homopolymers, random copolymers, block copolymers, etc., alone or in combination of two or more, or in combination with other monomers. Monomers used in combination with the polyene include α-olefins having 2 to 20 carbon atoms,
For example, ethylene, propylene, 1-butene, 4-methyl-1-
Pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-nonadecene, 1-eicosene, 9-
Methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, and styrene, vinyltoluene, acrylonitrile, methacrylonitrile, vinyl acetate, methyl methacrylate, ethyl acrylate The body can also be used.

As the polyene-based polymer, specifically,
Polybutadiene (BR), polyisoprene (IR), butyl rubber (IIB), natural rubber, nitrile-butadiene rubber (NBR), styrene-butadiene rubber (SB
R), chloroprene rubber (CR), ethylene-propylene-diene rubber (EPDM), and the like, but are not limited to these examples.

The carbon atom adjacent to the carbon-carbon double bond is active and facilitates abstraction of a hydrogen atom. The carbon-carbon double bond in the polymer is not particularly limited, and may be present in the main chain in the form of a vinylene group or in the side chain in the form of a vinyl group.

These polyene polymers preferably have a carboxylic acid group, a carboxylic acid anhydride group, or a hydroxyl group introduced therein. Examples of the monomer used to introduce these functional groups include the ethylenically unsaturated monomers having the above functional groups.

As these monomers, it is desirable to use unsaturated carboxylic acids or derivatives thereof. Specifically, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid Α, β-unsaturated carboxylic acids such as acids, bicyclo [2,2,
1] unsaturated carboxylic acids such as hept-2-ene-5,6-dicarboxylic acid, α, β unsaturated carboxylic anhydrides such as maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo [2,2,1] Unsaturated carboxylic acid anhydrides such as hept-2-ene-5,6-dicarboxylic anhydride.

The acid modification of the polyene polymer is carried out by graft copolymerizing an unsaturated carboxylic acid or a derivative thereof with a resin having a carbon-carbon double bond as a base polymer by a known means. Although it is produced, it can also be produced by randomly copolymerizing the above-mentioned polyene and unsaturated carboxylic acid or its derivative.

An acid-modified polyene-based polymer particularly suitable for the purpose of the present invention is an unsaturated carboxylic acid or a derivative thereof, which is used in an amount of 0.1 to 1%.
It is preferably contained in an amount of from 01 to 10 mol%. When the content of the unsaturated carboxylic acid or its derivative is in the above range, the acid-modified polyene-based polymer can be dispersed well in another resin (matrix resin), and oxygen can be absorbed smoothly. Further, a hydroxyl group-modified polyene polymer having a hydroxyl group at a terminal can also be used favorably.

The polyene polymer used in the present invention preferably has a Mooney viscosity ML _{1 + 4} (100 ° C.) in the range of 10 to 250 from the viewpoint of processability of the oxygen-absorbing resin composition.

Transition metal catalyst: The transition metal catalyst (B) serves as a catalyst for the oxidation reaction of the oxidizable thermoplastic resin (A), and an organic acid salt or an organic complex salt of a transition metal is preferably used. . As the transition metal catalyst to be used, a Group VIII metal component of the periodic table such as iron, cobalt and nickel is preferable. In addition, a Group I metal such as copper and silver: a Group IV metal such as tin, titanium and zirconium , Vanadium group V, chromium, etc. VI
Group VII metal components such as manganese. Among these metal components, the cobalt component has a high oxygen absorption rate and is particularly suitable.

The transition metal catalyst is generally used in the form of a low-valent inorganic or organic acid salt or a complex salt of the above-mentioned transition metal. Examples of the inorganic acid salts include halides such as chlorides, sulfur oxyacid salts such as sulfates, nitrogen oxyacid salts such as nitrates, phosphorus oxyacid salts such as phosphates, and silicates. On the other hand, examples of the organic acid salt include carboxylate, sulfonate, phosphonate and the like, and carboxylate is suitable for the purpose of the present invention. Specific examples thereof include acetic acid, propionic acid, and isopropionate. Acid, butanoic acid, isobutanoic acid, pentanoic acid, isopentanoic acid, hexanoic acid, heptanoic acid, isoheptanoic acid, octanoic acid,
-Ethylhexanoic acid, nonanoic acid, 3,5,5-trimethylhexanoic acid, decanoic acid, neodecanoic acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, arachidic acid, lindelic acid, tuzu Transition metal salts such as acids, petroselinic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, formic acid, oxalic acid, sulfamic acid, and naphthenic acid. On the other hand, as the complex of the transition metal, a complex with β-diketone or β-keto acid ester is used, and β-diketone or β-diketone
Examples of keto acid esters include acetylacetone,
Ethyl acetoacetate, 1,3-cyclohexadione, methylenebis-1,3-cyclohexadione, 2-benzyl-1,3-cyclohexadione, acetyltetralone,
Palmitoyltetralone, stearoyltetralone, benzoyltetralone, 2-acetylcyclohexanone,
2-benzoylcyclohexanone, 2-acetyl-1,
3-cyclohexanedione, benzoyl-p-chlorobenzoylmethane, bis (4-methylbenzoyl) methane, bis (2-hydroxybenzoyl) methane, benzoylacetone, tribenzoylmethane, diacetylbenzoylmethane, stearoylbenzoylmethane, palmitoylbenzoylmethane, Lauroylbenzoylmethane, dibenzoylmethane, bis (4-chlorobenzoyl) methane, bis (methylene-3,4-dioxybenzoyl) methane, benzoylacetylphenylmethane, stearoyl (4-methoxybenzoyl) methane, butanoylacetone, Stearoylmethane, acetylacetone, stearoylacetone, bis (cyclohexanoyl) -methane, dipivaloylmethane, and the like can be used.

In the oxygen-absorbing resin composition (1) used in the present invention, the transition metal catalyst (B) is contained as a metal in an amount of 10 to 6000 ppm, particularly 50 to 2,000 ppm, based on the thermoplastic resin (A). Is desirable. To blend the transition metal catalyst (B) with the resin (A),
Various means can be used. For example, the transition metal catalyst (B) can be simply blended with the resin by a dry method. However, since the transition metal catalyst (B) is in a small amount as compared with the resin, the transition metal catalyst (B) is generally used in order to perform homogeneous blending. (B) is dissolved in an organic solvent, this solution is mixed with a powder or a granular resin, and if necessary, the mixture is dried under an inert atmosphere.

Solvents for dissolving the transition metal catalyst include alcohol solvents such as methanol, ethanol and butanol, ether solvents such as dimethyl ether, diethyl ether, methyl ethyl ether, tetrahydrofuran and dioxane, and ketone solvents such as methyl ethyl ketone and cyclohexanone. Solvents and hydrocarbon solvents such as n-hexane and cyclohexane can be used, and it is generally preferable to use the transition metal catalyst at a concentration such that the concentration becomes 5 to 90% by weight.

The mixing of the oxidizing polymer component and the transition metal catalyst and the subsequent storage are preferably carried out in a non-oxidizing atmosphere so as to prevent the oxidation of the composition in the preceding stage. For this purpose, mixing or drying under reduced pressure or in a nitrogen stream is preferred. This mixing and drying can be performed at a stage prior to the molding step by using an extruder or an injection machine equipped with a vent type or a dryer. Also, prepare a masterbatch of the oxidizable polymer component containing a relatively high concentration of the transition metal catalyst,
The masterbatch can be dry blended with an unblended polymer to prepare the oxygen-absorbing resin composition of the present invention.

The oxygen-absorbing resin composition used in the present invention is not generally necessary, but may optionally contain a known activator. Suitable examples of activators include, but are not limited to, polyethylene glycol,
Hydroxyl and / or carboxyl group-containing polymers such as polypropylene glycol, ethylene vinyl alcohol copolymer, ethylene / methacrylic acid copolymer, and various ionomers. These hydroxyl and / or carboxyl group-containing polymers are used in an amount of 3 parts per 100 parts by weight of the polyamide resin.
It can be added in an amount of 0 parts by weight or less, particularly 0.01 to 10 parts by weight. The oxygen-absorbing resin composition used in the present invention includes a filler, a coloring agent, a heat stabilizer, a weather stabilizer, an antioxidant, an antioxidant, a light stabilizer, an ultraviolet absorber, an antistatic agent, a metal soap, A well-known resin compounding agent such as a lubricant such as wax, a modifying resin or rubber, etc. can be compounded according to a well-known formulation. For example, the incorporation of a lubricant improves biting of the resin into the screw. Lubricants include metal soaps such as magnesium stearate and calcium stearate, hydrocarbons such as fluid, natural or synthetic paraffin, microwax, polyethylene wax, chlorinated polyethylene wax, and fatty acids such as stearic acid and lauric acid. Those of fatty acid monoamides or bisamides, such as stearic acid amide, balmitic acid amide, valic acid amide, oleic acid amide, esylic acid amide, methylenebisstearamide, ethylenebisstearamide, butyl stearate, hydrogenated castor oil,
Ester type such as ethylene glycol monostearate, alcohol type such as cetyl alcohol and stearyl alcohol, and a mixture thereof are generally used. The amount of the lubricant added is 50 to 1 based on the polyamide.
A range of 000 ppm is appropriate.

[Oxygen Barrier Resin] As the oxygen barrier resin, the above-mentioned thermoplastic resin which has an oxygen barrier property and can be thermoformed is used. The most suitable example of the oxygen-barrier resin is an ethylene-vinyl alcohol copolymer. For example, ethylene-vinyl acetate copolymer having an ethylene content of 20 to 60 mol%, particularly 25 to 50 mol%. A saponified copolymer obtained by saponifying a polymer so as to have a saponification degree of 96 mol% or more, particularly 99 mol% or more is used. This ethylene
The saponified vinyl alcohol copolymer should have a molecular weight sufficient to form a film, and is generally 0.01 dl / g or more as measured at 30 ° C. in a 85:15 phenol: water mixture by weight. In particular, it is desirable to have a viscosity of 0.05 dl / g or more.

Other examples of the oxygen-barrier resin having the above-mentioned properties include polyamides having an amide group number of 5 to 50, especially 6 to 20, per 100 carbon atoms; 6, Nylon 6.6, Nylon
6/6 ・ 6 copolymer, meta-xylylene adipamide, nylon 6,10, nylon 11, nylon 12, nylon 1
3, or a blend of two or more of these. These polyamides should also have a molecular weight sufficient to form a film, and have a relative viscosity (ηrel) measured at a concentration of 1.0 g / dl in concentrated sulfuric acid at a temperature of 30 ° C. of 1.1 or more, especially 1.5 or more. Is desirable. Further, as an oxygen barrier intermediate layer for imparting oxygen barrier properties, metal, for example, a deposited film of aluminum or other gas barrier deposited film, such as a hard carbon film, a silicon oxide film,
A titanium oxide film or the like can be given. These vapor-deposited films are generally formed on the surface of a stretched film such as biaxially-stretched polyethylene terephthalate by chemical vapor deposition (CVD), and are used in a state where the vapor-deposited film is located on the inner surface side of the container.

[Moisture Resistant Resin] In the present invention, as the moisture resistant resin used for the outer layer and the inner layer of the container, an olefin resin, a thermoplastic polyester resin or the like is used depending on the application.

Examples of the olefin resin include low density, medium density or high density polyethylene, linear low density polyethylene, ionomer, homopolypropylene, block copolymer or random copolymer type polypropylene, linear low density polyethylene, ethylene Propylene copolymer,
Polybutene-1, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, ethylene-propylene-
Butene-1 copolymer, cyclic olefin copolymer (CO
C) and the like are used.

The polyester resin used as the moisture-resistant resin in the present invention is a homopolyester or copolymer derived from a dibasic acid mainly composed of terephthalic acid or naphthalenedicarboxylic acid and a diol mainly composed of ethylene glycol or butylene glycol. It is preferably polyester.

Examples of dibasic acids other than terephthalic acid and naphthalenedicarboxylic acid include isophthalic acid, P-β-oxyethoxybenzoic acid, diphenoxyethane-4,4'-
Examples thereof include dicarboxylic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, adipic acid and sebacic acid.

The diol components other than ethylene glycol and butylene glycol include propylene glycol, neopentyl glycol, 1,6-hexylene glycol, diethylene glycol, triethylene glycol, cyclohexane dimethanol, and ethylene oxide adduct of bisphenol A. Glycol components can be mentioned.

The homopolyester or copolyester should have a molecular weight in the range of film formation,
The intrinsic viscosity [IV] measured using a phenol / tetrachloroethane mixed solvent as a solvent is 0.5 to 1.
5, preferably in the range of 0.6 to 1.5.

[Laminated Structure] The laminated body used in the container of the present invention has the laminated structure described above, but the inner layer of the moisture-resistant resin has a thickness of 30 to 500 μm, and the first layer of the oxygen barrier resin has a thickness of 5 to 250 μm. Thickness, oxygen-absorbing resin layer is 5
The thickness of the second layer of the oxygen barrier resin is 5 to 250 μm, and the thickness of the moisture-resistant outer surface layer is 30 to 5 μm.
It preferably has a thickness of 00 μm. If the thickness of the moisture-resistant resin inner layer is less than the above range, sanitary properties and flavor retention tend to decrease, and if the thickness exceeds the above range, oxygen absorption in the package tends to decrease. If the thickness of the first layer of the oxygen barrier resin is below the above range, the preservability of oxygen absorption in an empty container tends to be insufficient, while if the thickness exceeds the above range, the oxygen absorption in the package will be insufficient. This is not preferred because the properties tend to decrease and the cost of the package increases. If the thickness of the oxygen-absorbing resin layer is less than the above range, the absorbency of oxygen in the package is also not preferable because the absorbency of the oxygen permeated through the vessel wall is also reduced. An increase in oxygen absorbability cannot be expected and is economically disadvantageous. When the thickness of the second layer of the oxygen barrier resin is less than the above range, the preservability of oxygen absorbency in an empty container tends to be insufficient, and the barrier property against oxygen permeated through the vessel wall is not preferable, and If the thickness is greater than the above range, no particular increase in oxygen barrier properties can be expected, and this is economically disadvantageous, which is not preferable. When the thickness of the outer layer of the moisture-resistant resin is less than the above range, the protection effect of the moisture-resistant resin tends to decrease, while when the thickness exceeds the above range, the flexibility and flexibility of the container tend to decrease.

In the production of the laminate, an adhesive resin may be interposed between the resin layers as required. Examples of such an adhesive resin include a carbonyl (—C (O) —) group based on carboxylic acid, carboxylic anhydride, carboxylate, carboxylic amide, carboxylic ester, or the like as a main chain or a side chain. ~ 700 milliequivalents (meq)
/ 100 g resin, especially a thermoplastic resin containing at a concentration of 10 to 500 meq / 100 g resin. Suitable examples of the adhesive resin include ethylene-acrylic acid copolymer, ion-crosslinked olefin copolymer, maleic anhydride-grafted polyethylene, maleic anhydride-grafted polypropylene, acrylic acid-grafted polyolefin, ethylene-vinyl acetate copolymer, copolymer One or a combination of two or more such as a polymerized polyester and a copolymerized polyamide. These resins are useful for lamination by coextrusion or sandwich lamination. In addition, a thermosetting adhesive resin such as an isocyanate-based or epoxy-based resin is used for the adhesive lamination of the oxygen barrier resin film and the olefin-based resin film formed in advance. Generally, it is preferable to use these adhesive layers in a thickness of 0.1 to 100 μm.

In the multilayer packaging container of the present invention, the overall thickness varies depending on the application, but is generally 100 to 2 mm.
It is preferably 000 μm, especially 200 to 1000 μm.

[Packaging Container] The oxygen-absorbing container of the present invention comprises:
It is used in the form of three-dimensional containers such as cups, trays, bottles and tubes.

The packaging container of the present invention can be manufactured by a method known per se except for using the above-mentioned laminated structure. For example, a film, sheet or tube is formed by melt-kneading the resin composition with an extruder and extruding the resin composition into a predetermined shape through a T-die, a circular die (ring die) or the like. Further, after the resin composition is melt-kneaded with an injection machine, the resin composition is injected into an injection mold to manufacture a container or a preform for manufacturing the container. Further, the resin composition is extruded into a certain molten resin mass through an extruder, and is compressed and molded by a mold, thereby producing a container and a preform for producing the container. The molded article may take the form of a preform for sheet molding, a parison or pipe for bottle or tube formation, a preform for bottle or tube molding, or the like. Forming a bottle from a parison, pipe or preform is facilitated by pinching off the extrudate with a pair of split dies and blowing fluid into the interior. Further, after cooling the pipe or the preform, the pipe or the preform is heated to a stretching temperature, stretched in an axial direction, and blow-stretched in a circumferential direction by a fluid pressure to obtain a stretch blow bottle or the like. In addition,
By applying the film or sheet to means such as vacuum forming, pressure forming, overhang forming, and plug assist forming,
A cup-shaped or tray-shaped packaging container or a lid member made of a film or sheet is obtained.

A packaging material such as a film can be used as a packaging bag of various forms, and the bag can be produced by a bag production method known per se. Gusseted pouches, standing pouches, pillow packaging bags, and the like are included, but are not limited to these examples.

For the production of the multilayer extruded product, a co-extrusion molding method known per se can be used. For example, the above-mentioned method is repeated except that a multi-layered die is used using a number of extruders according to the type of resin. Extrusion may be performed in the same manner. Further, in the production of a multilayer injection molded article, a multilayer injection molded article can be produced by a co-injection method or a sequential injection method using an injection molding machine of a number corresponding to the type of the resin. Further, extrusion coating or sandwich lamination can be used for the production of a multilayer film or multilayer sheet, and a multilayer film or sheet can also be produced by dry lamination of a film formed in advance.

The packaging container of the present invention is useful as a container capable of preventing a decrease in the flavor of the contents due to oxygen. Fillable contents include beer, wine, fruit juice, carbonated soft drinks for beverages, fruits, nuts, vegetables, meat products, infant foods, coffee, jam, mayonnaise, ketchup, edible oil, dressing, sauces for foods , Boiled foods, dairy products, etc., and other products such as pharmaceuticals, cosmetics, gasoline, etc., which are easily deteriorated in the presence of oxygen, but are not limited to these examples.

[0076]

The present invention will be further described with reference to the following examples, but the present invention is not limited to these examples.

(Example 1) Polypropylene (PP: manufactured by Grand Polymer Co., Ltd.) / Adhesive layer A in order from the outer layer
(Maleic anhydride-modified polypropylene: Mitsui Chemicals, Inc.
Admer QB550) Ethylene vinyl alcohol copolymer (EVOH): manufactured by Kuraray Co., Ltd.) / Adhesive layer A
/ Polymeta-xylene adipamide (MX nylon: manufactured by Mitsubishi Gas Chemical Co., Ltd.) + Co (200 ppm) / adhesive layer A / EVOH / adhesive layer A / PP, the layer composition ratio (4
1: 2.5: 2.5: 2.5: 2.5: 2.5: 2.
5: 2.5: 41.5) was formed by co-extrusion, and the multilayer parison was formed into a multilayer container having a thickness of 0.6 mm and a capacity of 1000 ml by melt blow molding. The container was capped empty and stored at room temperature.

(Example 2) In order from the outer layer, polyethylene terephthalate (PET: manufactured by Kuraray Co., Ltd., for direct blow) / adhesive layer B (Admer SF730, manufactured by Mitsui Chemicals, Inc.) MX nylon: MX nylon + Co (2
00 ppm) / MX nylon / adhesive layer B / PET, layer composition ratio (43: 2.5: 2.5: 2.5: 2.
5: 2.5: 44.5) was formed by co-extrusion, and the multilayer parison was formed into a multilayer container having a thickness of 0.4 mm and a capacity of 500 ml by melt blow molding.
The container was capped empty and stored at room temperature.

(Comparative Example 1) In order from the outer layer, PP / adhesive layer A / MX nylon + Co (200 ppm) / adhesive layer A / PP, and the layer composition ratio (46: 2.5: 2.5:
2.5: 46.5) A parison consisting of a wall was co-extruded, and the multilayer parison was formed into a multilayer container having a thickness of 0.6 mm and a capacity of 1000 ml by melt blow molding.
The container was capped empty and stored at room temperature. The oxygen absorption amounts of the above three types of samples were measured, and the oxygen absorption rate per bottle at each time was obtained. Table 1 shows the results.

[0080]

Table 1 Oxygen absorption rate (cc / day) Storage period 3 days 1 month 3 months 6 months Example 1 0.114 0.115 0.114 0.114 Example 2 0.087 0.089 0.088 0 0.087 Comparative Example 1 0.228 0.230 0.108 0.068

Example 3 Polypropylene having a thickness of 70 μm / silica-deposited PET film having a thickness of 12 μm (GL-AU manufactured by Toppan Printing Co., Ltd.) / MX nylon having a thickness of 15 μm + Co (200 ppm) / thickness A laminated film was prepared using an isocyanate-based adhesive so that silica-deposited PET film having a thickness of 12 μm / PP having a thickness of 60 μm was obtained. This film was used as a surface material and a back material, and the peripheral portion was heat-sealed under atmospheric pressure (oxygen concentration: 20.9%) to have a content of 180 ml and a size of 126 mm × 165 m.
m pouches. This was stored at room temperature.

(Comparative Example 2) PP having a thickness of 70 μm / thickness 1
5 μm MX nylon + Co (200 ppm) / thickness 6
A laminated film was prepared using an isocyanate-based adhesive so that the PP became 0 μm. This film was used as a surface material and a back surface material, and under atmospheric pressure (oxygen concentration 20.9
%), Heat-sealing the peripheral part and the content is 180 ml,
A pouch having a size of 126 mm x 165 mm was manufactured. This was stored at room temperature. The oxygen absorption amounts of the above two types of samples were measured, and the oxygen absorption rates at each time were obtained. Table 2 shows the results.

[0083]

Table 2 Oxygen absorption rate (cc / day) Storage period 3 days 1 month 3 months 6 months Example 3 0.10 0.11 0.11 0.11 Comparative Example 2 0.31 0.37 0.17 0 .09

[0084]

According to the present invention, in an oxygen-absorbing container provided with an oxygen-absorbing resin layer containing an oxidizing polymer and a transition metal-based oxidation catalyst as an intermediate layer, the oxygen-absorbing resin layer is By sandwiching with an oxygen barrier resin, it is possible to maintain oxygen absorption performance for a long period of time even when stored in an empty container in the air.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a sectional structure of an oxygen-absorbing container of the present invention.

 ────────────────────────────────────────────────── ─── Continuing on the front page F-term (reference) 3E033 AA01 AA08 AA10 BA13 BB08 CA20 FA02 FA03 4F100 AA20 AK01A AK01B AK01D AK07 AK46B AK46D AK69B AK69D BA03 BA06 BA07 BA10B BA10C BA10D J10E EH20E JB03 J66D

Claims (3)

[Claims] 1. An oxygen-absorbing container provided with an oxygen-absorbing resin layer containing an oxidizing polymer and a transition metal-based oxidation catalyst as an intermediate layer, wherein the oxygen-absorbing resin layer has an oxygen-barrier resin and / or Alternatively, an oxygen-absorbing container excellent in storability in an empty container, which is sandwiched by an oxygen-barrier vapor-deposited layer. 2. The oxygen-absorbing container according to claim 1, wherein the oxygen-barrier resin is an ethylene vinyl alcohol copolymer. 3. The oxygen-absorbing container according to claim 1, wherein the oxygen-barrier resin is a polyamide derived from a xylylene group-containing diamine and an aliphatic dicarboxylic acid.