JP5954325B2 - Multilayer sheet - Google Patents

Description

  The present invention relates to a multilayer sheet having oxygen barrier performance and oxygen absorption performance.

  Polyamide obtained from polycondensation reaction of xylylenediamine and aliphatic dicarboxylic acid, for example, polyamide obtained from metaxylylenediamine and adipic acid (hereinafter referred to as nylon MXD6) has high strength, high elastic modulus, oxygen, carbonic acid Since it shows low permeability to gaseous substances such as gas, odor and flavor, it is widely used as a gas barrier material in the field of packaging materials. Nylon MXD6 has better thermal stability when melted than other gas barrier resins, and therefore coextruded or coextruded with thermoplastic resins such as polyethylene terephthalate (hereinafter abbreviated as PET), nylon 6 and polypropylene. Injection molding or the like is possible. Therefore, nylon MXD6 is used as a gas barrier layer constituting a multilayer structure.

  In recent years, nylon MXD6 is added and mixed with a small amount of transition metal compound to give nylon MXD6 an oxygen-absorbing function, and this is used as an oxygen barrier material constituting containers and packaging materials. Nylon MXD6 absorbs the incoming oxygen and nylon MXD6 also absorbs oxygen remaining inside the container, so that a method for improving the storage stability of the contents over conventional containers using oxygen-barrier thermoplastic resin is practical. (See, for example, Patent Documents 1 and 2).

  On the other hand, oxygen absorbers have been used for a long time to remove oxygen in the container. For example, Patent Documents 3 and 4 describe an oxygen-absorbing multilayer body and an oxygen-absorbing film in which an oxygen absorbent such as iron powder is dispersed in a resin. Patent Document 5 describes a product having an oxygen scavenging layer containing an ethylenically unsaturated compound such as polybutadiene and a transition metal catalyst such as cobalt, and an oxygen barrier layer such as polyamide.

JP 2003-341747 A Japanese Patent No. 2991437 JP-A-2-72851 Japanese Patent Laid-Open No. 4-90848 Japanese Patent Laid-Open No. 5-115776

The oxygen-absorbing multilayer body and oxygen-absorbing film in which an oxygen absorbent such as iron powder is dispersed in the resin are opaque due to the resin being colored by the oxygen absorbent such as iron powder. There is an application restriction that it cannot be used in the field.
On the other hand, a resin composition containing a transition metal such as cobalt has an advantage that it can be applied to packaging containers that require transparency, but is not preferred because the resin composition is colored by a transition metal catalyst. In these resin compositions, the resin is oxidized by absorbing oxygen by the transition metal catalyst. Specifically, in nylon MXD6, generation of radicals due to extraction of hydrogen atoms from the methylene chain adjacent to the arylene group of the polyamide resin by transition metal atoms, and generation of peroxy radicals by addition of oxygen molecules to the radicals It is thought to occur by various reactions such as extraction of hydrogen atoms by peroxy radicals. Since the resin is oxidized by oxygen absorption by such a mechanism, a decomposition product is generated and an unpleasant odor is generated in the contents of the container, or the color tone or strength of the container is impaired due to oxidative degradation of the resin. is there.

  The problem to be solved by the present invention is that oxygen barrier performance is expressed, oxygen absorption performance can be expressed without containing a transition metal, and the strength of the oxygen absorption barrier layer as oxygen absorption progresses The object is to provide a multi-layer sheet with very little reduction.

［前記一般式（Ｉ−３）中、ｍは２〜１８の整数を表す。前記一般式（ＩＩ−１）中、ｎは２〜１８の整数を表す。前記一般式（ＩＩ−２）中、Ａｒはアリーレン基を表す。前記一般式（ＩＩＩ）中、Ｒは置換もしくは無置換のアルキル基又は置換もしくは無置換のアリール基を表す。］The present invention provides the following multilayer sheet.
A multilayer sheet comprising a layer (A) containing a polyamide resin (A) and a layer (B) containing the resin (B) as a main component,
The polyamide resin (A) is
An aromatic diamine unit represented by the following general formula (I-1), an alicyclic diamine unit represented by the following general formula (I-2), and a straight chain represented by the following general formula (I-3) 25 to 50 mol% of diamine units containing at least 50 mol% in total of at least one diamine unit selected from the group consisting of aliphatic diamine units;
A dicarboxylic acid unit containing a total of 50 mol% or more of a linear aliphatic dicarboxylic acid unit represented by the following general formula (II-1) and / or an aromatic dicarboxylic acid unit represented by the following general formula (II-2) 25 to 50 mol%,
The multilayer sheet containing 0.1-50 mol% of structural units represented by the following general formula (III).

[In the general formula (I-3), m represents an integer of 2 to 18. In the general formula (II-1), n represents an integer of 2 to 18. In the general formula (II-2), Ar represents an arylene group. In the general formula (III), R represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. ]

The multilayer sheet of the present invention exhibits oxygen barrier performance and can exhibit oxygen absorption performance without containing a transition metal, and the strength of the oxygen absorption barrier layer is extremely reduced as oxygen absorption progresses. small. Further, since the strength of the oxygen absorbing barrier layer is maintained even in long-term use, delamination is unlikely to occur when the multilayer sheet is formed of a laminate.
The container formed of the multilayer sheet is excellent in suppressing the oxidative deterioration of the contents, hardly generating substances that cause off-flavors and flavor changes, and excellent in flavor retention.

<< Multi-layer sheet >>
The multilayer sheet of the present invention comprises a layer (A) containing a polyamide resin (A) (hereinafter also referred to as “oxygen absorption barrier layer”), and a layer (B) containing the resin (B) as a main component. At least.
The layer structure in the multilayer sheet of the present invention is not particularly limited, and the number and type of layers (A) and layers (B) are not particularly limited. For example, an A / B configuration consisting of one layer (A) and one layer (B) may be used, and B / A / consisting of one layer (A) and two layers (B). A three-layer structure of B may be used. Also, a five-layer configuration of B1 / B2 / A / B2 / B1 composed of one layer (A) and two types and four layers (B) of the layer (B1) and the layer (B2) may be used. Furthermore, the multilayer sheet of the present invention may include an arbitrary layer such as an adhesive layer (AD) as necessary, and has, for example, a seven-layer configuration of B1 / AD / B2 / A / B2 / AD / B1. Also good.

1. Layer containing polyamide resin (A) (A) (oxygen absorption barrier layer)
In the present invention, the oxygen absorption barrier layer can exhibit oxygen absorption performance and oxygen barrier performance by containing a specific polyamide resin (hereinafter also referred to as “polyamide resin (A)”) described later. The polyamide resin (A) contained in the oxygen absorption barrier layer may be one kind or a combination of two or more kinds.
In this invention, an oxygen absorption barrier layer contains a polyamide resin (A) as a main resin component. A resin other than the polyamide resin (A) may be added to the oxygen absorption barrier layer, but the ratio of the polyamide resin (A) in the total resin of the oxygen absorption barrier layer is preferably more than 95% by mass. The resin contained in the oxygen absorption barrier layer may be only the polyamide resin (A), and the ratio of the polyamide resin (A) in the total resin of the oxygen absorption barrier layer is preferably 100% by mass or less.
As described above, a resin other than the polyamide resin (A) may be added to the oxygen-absorbing barrier layer, and as the added resin, performance that is desired to be imparted to the oxygen-absorbing barrier layer as long as the object of the present invention is not impaired. Depending on the above, various conventionally known resins may be used. For example, from the viewpoint of imparting impact resistance, pinhole resistance and flexibility, polyolefins such as polyethylene and polypropylene, various modified products thereof, polyolefin elastomers, polyamide elastomers, styrene-butadiene copolymer resins and hydrogens thereof. Additives processed, various thermoplastic elastomers typified by polyester elastomers, various polyamides such as nylon 6, 66, 12 and nylon 12, etc. From the viewpoint of further imparting oxygen absorption performance, polybutadiene and modified polybutadiene And carbon-carbon unsaturated double bond-containing resins. The additive resin may be one kind or a combination of two or more kinds. The ratio of the additive resin in the total resin of the oxygen absorption barrier layer is preferably 5% by mass or less.
In addition to the polyamide resin (A), the oxygen-absorbing barrier layer may contain an additive to be described later (hereinafter also referred to as “additive (C)”) depending on the desired performance and the like. The content of the polyamide resin (A) in the oxygen absorption barrier layer is preferably 90% by mass to 100% by mass, and 95% by mass to 100% by mass from the viewpoints of moldability, oxygen absorption performance, and oxygen barrier performance. It is more preferable that
The thickness of the oxygen absorption barrier layer is preferably 2 to 100 μm, more preferably from the viewpoint of securing various physical properties such as flexibility required for the multilayer sheet while enhancing oxygen absorption performance and oxygen barrier performance. It is 5-90 micrometers, More preferably, it is 10-80 micrometers.

1-1. Polyamide resin (A)
<Configuration of polyamide resin (A)>
In the present invention, the polyamide resin (A) is an aromatic diamine unit represented by the following general formula (I-1), an alicyclic diamine unit represented by the following general formula (I-2), and the following general formula. 25 to 50 mol% of diamine units containing at least 50 mol% in total of at least one diamine unit selected from the group consisting of linear aliphatic diamine units represented by (I-3), and the following general formula (II-1) 25 to 50 mol% of dicarboxylic acid units including a total of 50 mol% or more of the linear aliphatic dicarboxylic acid units represented by formula (II) and the aromatic dicarboxylic acid units represented by the following general formula (II-2): A tertiary hydrogen-containing carboxylic acid unit (preferably a structural unit represented by the following formula (III)) is contained in an amount of 0.1 to 50 mol%.

[In the general formula (I-3), m represents an integer of 2 to 18. In the general formula (II-1), n represents an integer of 2 to 18. In the general formula (II-2), Ar represents an arylene group. In the general formula (III), R represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. ]
However, the total of the diamine unit, the dicarboxylic acid unit, and the tertiary hydrogen-containing carboxylic acid unit shall not exceed 100 mol%. The polyamide resin (A) may further contain structural units other than those described above as long as the effects of the present invention are not impaired.

  In the polyamide resin (A), the content of the tertiary hydrogen-containing carboxylic acid unit is 0.1 to 50 mol%. If the content of the tertiary hydrogen-containing carboxylic acid unit is less than 0.1 mol%, sufficient oxygen absorption performance is not exhibited. On the other hand, if the content of the tertiary hydrogen-containing carboxylic acid unit exceeds 50 mol%, the tertiary hydrogen content is too high, and the physical properties such as gas barrier properties and mechanical properties of the polyamide resin (A) are lowered. When the secondary hydrogen-containing carboxylic acid is an amino acid, the peptide bond is continuous, so that the heat resistance is not sufficient, and a cyclic product composed of a dimer of amino acids is formed, thereby inhibiting polymerization. The content of the tertiary hydrogen-containing carboxylic acid unit is preferably 0.2 mol% or more, more preferably 1 mol% or more, and preferably from the viewpoint of oxygen absorption performance and the properties of the polyamide resin (A). It is 40 mol% or less, More preferably, it is 30 mol% or less.

In the polyamide resin (A), the content of the diamine unit is 25 to 50 mol%, and preferably 30 to 50 mol% from the viewpoint of oxygen absorption performance and polymer properties. Similarly, in the polyamide resin (A), the content of the dicarboxylic acid unit is 25 to 50 mol%, preferably 30 to 50 mol%.
The proportion of the content of the diamine unit and the dicarboxylic acid unit is preferably substantially the same from the viewpoint of the polymerization reaction, and the content of the dicarboxylic acid unit is ± 2 mol% of the content of the diamine unit. More preferred. If the content of the dicarboxylic acid unit exceeds the range of ± 2 mol% of the content of the diamine unit, the degree of polymerization of the polyamide resin (A) becomes difficult to increase, so it takes a lot of time to increase the degree of polymerization, Deterioration is likely to occur.

[Diamine unit]
The diamine unit in the polyamide resin (A) is an aromatic diamine unit represented by the general formula (I-1), an alicyclic diamine unit represented by the general formula (I-2), and the general formula. The total content of at least one diamine unit selected from the group consisting of linear aliphatic diamine units represented by (I-3) is 50 mol% or more in the diamine units, and the content is preferably 70 mol%. Above, more preferably 80 mol% or more, still more preferably 90 mol% or more, and preferably 100 mol% or less.

  Examples of the compound that can constitute the aromatic diamine unit represented by the general formula (I-1) include orthoxylylenediamine, metaxylylenediamine, and paraxylylenediamine. These can be used alone or in combination of two or more.

Examples of the compound that can constitute the alicyclic diamine unit represented by the formula (I-2) include bis (amino) such as 1,3-bis (aminomethyl) cyclohexane and 1,4-bis (aminomethyl) cyclohexane. Methyl) cyclohexanes. These can be used alone or in combination of two or more.
Bis (aminomethyl) cyclohexanes have structural isomers, but by increasing the cis-isomer ratio, the crystallinity is high and good moldability can be obtained. On the other hand, if the cis-isomer ratio is lowered, a transparent material with low crystallinity can be obtained. Therefore, when it is desired to increase the crystallinity, the cis-isomer content ratio in the bis (aminomethyl) cyclohexane is preferably 70 mol% or more, more preferably 80 mol% or more, and still more preferably 90 mol% or more. . On the other hand, when it is desired to lower the crystallinity, the cis body content ratio in the bis (aminomethyl) cyclohexanes is preferably 50 mol% or less, more preferably 40 mol% or less, still more preferably 30 mol% or less. .

In said general formula (I-3), m represents the integer of 2-18, Preferably it is 3-16, More preferably, it is 4-14, More preferably, it is 6-12.
Examples of the compound that can constitute the linear aliphatic diamine unit represented by the general formula (I-3) include ethylenediamine, 1,3-propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, and heptamethylenediamine. And aliphatic diamines such as octamethylene diamine, nonamethylene diamine, decamethylene diamine, undecamethylene diamine, and dodecamethylene diamine, but are not limited thereto. Among these, hexamethylenediamine is preferable. These can be used alone or in combination of two or more.

  As the diamine unit in the polyamide resin (A), in addition to imparting excellent gas barrier properties to the polyamide resin (A), it improves transparency and color tone and facilitates moldability of general-purpose thermoplastic resins. From the viewpoint, it preferably contains an aromatic diamine unit represented by the general formula (I-1) and / or an alicyclic diamine unit represented by the general formula (I-2). From the viewpoint of imparting appropriate crystallinity to (A), it is preferable to include a linear aliphatic diamine unit represented by the general formula (I-3). In particular, from the viewpoint of oxygen absorption performance and the properties of the polyamide resin (A), it is preferable that the aromatic diamine unit represented by the general formula (I-1) is included.

  The diamine unit in the polyamide resin (A) is a metaxylylenediamine unit from the viewpoint of facilitating the moldability of a general-purpose thermoplastic resin in addition to exhibiting excellent gas barrier properties in the polyamide resin (A). The content is preferably 50 mol% or more, and the content is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, and preferably 100 mol% or less.

  Examples of the compound that can constitute a diamine unit other than the diamine unit represented by any one of the general formulas (I-1) to (I-3) include aromatic diamines such as paraphenylenediamine, and 1,3-diaminocyclohexane. Alicyclic diamines such as 1,4-diaminocyclohexane, N-methylethylenediamine, 2-methyl-1,5-pentanediamine, and 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane Examples include, but are not limited to, group diamines, polyether diamines having ether bonds represented by Huntsman's Jeffamine and elastamine (both are trade names), and the like. These can be used alone or in combination of two or more.

[Dicarboxylic acid unit]
The dicarboxylic acid unit in the polyamide resin (A) is a linear aliphatic group represented by the general formula (II-1) from the viewpoints of reactivity during polymerization and crystallinity and moldability of the polyamide resin (A). The dicarboxylic acid unit and / or the aromatic dicarboxylic acid unit represented by the general formula (II-2) is contained in the dicarboxylic acid unit in a total of 50 mol% or more, and the content is preferably 70 mol% or more, more Preferably it is 80 mol% or more, More preferably, it is 90 mol% or more, Preferably it is 100 mol% or less.

The linear aliphatic dicarboxylic acid unit represented by the general formula (II-1) is necessary as a packaging material and a packaging container in addition to imparting an appropriate glass transition temperature and crystallinity to the polyamide resin (A). It is preferable at the point which can provide a softness | flexibility.
In said general formula (II-1), n represents the integer of 2-18, Preferably it is 3-16, More preferably, it is 4-12, More preferably, it is 4-8.
Examples of the compound that can constitute the linear aliphatic dicarboxylic acid unit represented by the general formula (II-1) include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1, Examples thereof include, but are not limited to, 10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, and the like. These can be used alone or in combination of two or more.

  The kind of the linear aliphatic dicarboxylic acid unit represented by the general formula (II-1) is appropriately determined according to the use. The linear aliphatic dicarboxylic acid unit in the polyamide resin (A) gives excellent gas barrier properties to the polyamide resin (A), and from the viewpoint of maintaining heat resistance after heat sterilization of the packaging material and packaging container. It is preferable that at least one selected from the group consisting of an adipic acid unit, a sebacic acid unit, and a 1,12-dodecanedicarboxylic acid unit is contained in a total of 50 mol% or more in the linear aliphatic dicarboxylic acid unit, The content is more preferably 70 mol% or more, still more preferably 80 mol% or more, particularly preferably 90 mol% or more, and preferably 100 mol% or less.

  The linear aliphatic dicarboxylic acid unit in the polyamide resin (A) is a linear aliphatic unit from the viewpoint of gas barrier properties of the polyamide resin (A) and thermal properties such as an appropriate glass transition temperature and melting point. It is preferable to contain 50 mol% or more in the dicarboxylic acid unit. In addition, the linear aliphatic dicarboxylic acid unit in the polyamide resin (A) is converted from the sebacic acid unit to the linear aliphatic dicarboxylic acid unit from the viewpoint of imparting appropriate gas barrier properties and molding processability to the polyamide resin (A). When the polyamide resin (A) is used for applications requiring low water absorption, weather resistance, and heat resistance, the 1,12-dodecanedicarboxylic acid unit is a linear aliphatic group. It is preferable to contain 50 mol% or more in the dicarboxylic acid unit.

The aromatic dicarboxylic acid unit represented by the general formula (II-2) facilitates the molding processability of packaging materials and packaging containers in addition to imparting further gas barrier properties to the polyamide resin (A). It is preferable in that
In the general formula (II-2), Ar represents an arylene group. The arylene group is preferably an arylene group having 6 to 30 carbon atoms, more preferably 6 to 15 carbon atoms, and examples thereof include a phenylene group and a naphthylene group.
Examples of the compound that can constitute the aromatic dicarboxylic acid unit represented by the general formula (II-2) include terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid, but are not limited thereto. is not. These can be used alone or in combination of two or more.

  The kind of the aromatic dicarboxylic acid unit represented by the general formula (II-2) is appropriately determined according to the use. The aromatic dicarboxylic acid unit in the polyamide resin (A) is a total of at least one selected from the group consisting of an isophthalic acid unit, a terephthalic acid unit, and a 2,6-naphthalenedicarboxylic acid unit in the aromatic dicarboxylic acid unit. The content is preferably 70 mol% or more, more preferably 80 mol% or more, particularly preferably 90 mol% or more, and preferably 100 mol% or less. is there. Among these, it is preferable to contain isophthalic acid and / or terephthalic acid in the aromatic dicarboxylic acid unit. The content ratio of the isophthalic acid unit to the terephthalic acid unit (isophthalic acid unit / terephthalic acid unit) is not particularly limited and is appropriately determined according to the application. For example, from the viewpoint of reducing the appropriate glass transition temperature and crystallinity, when the total of both units is 100, the molar ratio is preferably 0/100 to 100/0, more preferably 0/100 to 60/40, More preferably, it is 0 / 100-40 / 60, More preferably, it is 0 / 100-30 / 70.

  In the dicarboxylic acid unit in the polyamide resin (A), the content ratio of the linear aliphatic dicarboxylic acid unit to the aromatic dicarboxylic acid unit (linear aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit) is particularly limited. Rather, it is determined appropriately according to the application. For example, when the purpose is to increase the glass transition temperature of the polyamide resin (A) to lower the crystallinity of the polyamide resin (A), the linear aliphatic dicarboxylic acid units / aromatic dicarboxylic acid units are both units. When the total is 100, the molar ratio is preferably 0/100 to 60/40, more preferably 0/100 to 40/60, and still more preferably 0/100 to 30/70. Further, when the purpose is to lower the glass transition temperature of the polyamide resin (A) to impart flexibility to the polyamide resin (A), the linear aliphatic dicarboxylic acid unit / aromatic dicarboxylic acid unit is When the total is 100, the molar ratio is preferably 40/60 to 100/0, more preferably 60/40 to 100/0, and still more preferably 70/30 to 100/0.

  Examples of the compound that can constitute a dicarboxylic acid unit other than the dicarboxylic acid unit represented by the general formula (II-1) or (II-2) include oxalic acid, malonic acid, fumaric acid, maleic acid, 1,3- Examples of the dicarboxylic acid include benzenediacetic acid and 1,4-benzenediacetic acid, but are not limited thereto.

[Tertiary hydrogen-containing carboxylic acid unit]
In the present invention, the tertiary hydrogen-containing carboxylic acid unit in the polyamide resin (A) has at least one amino group and one carboxyl group from the viewpoint of polymerization of the polyamide resin (A), or two or more carboxyl groups. Have. Specific examples include structural units represented by any of the following general formulas (III), (IV), or (V).

[In the general formulas (III) to (V), R, R ¹ and R ² each represent a substituent, and A ^{1 to} A ³ each represent a single bond or a divalent linking group. However, the case where both A ¹ and A ² in the general formula (IV) are single bonds is excluded. ]

  In the present invention, the polyamide resin (A) includes a tertiary hydrogen-containing carboxylic acid unit. By containing such a tertiary hydrogen-containing carboxylic acid unit as a copolymerization component, the polyamide resin (A) can exhibit excellent oxygen absorption performance without containing a transition metal.

In the present invention, the mechanism by which the polyamide resin (A) having a tertiary hydrogen-containing carboxylic acid unit exhibits good oxygen absorption performance has not yet been clarified, but is estimated as follows. In a compound that can constitute a tertiary hydrogen-containing carboxylic acid unit, an electron-withdrawing group and an electron-donating group are bonded to the same carbon atom, so that unpaired electrons existing on the carbon atom are energetic. It is considered that a very stable radical is generated by a phenomenon called a captodative effect that is stabilized in a stable manner. That is, the carboxyl group is an electron withdrawing group, and the carbon to which the adjacent tertiary hydrogen is bonded becomes electron deficient (δ ⁺ ), so the tertiary hydrogen also becomes electron deficient (δ ⁺ ) Dissociates as a radical. When oxygen and water are present here, it is considered that oxygen reacts with this radical to show oxygen absorption performance. It has also been found that the higher the humidity and temperature, the higher the reactivity.

In the general formulas (III) to (V), R, R ¹ and R ² each represent a substituent. Examples of the substituent represented by R, R ¹ and R ² in the present invention include a halogen atom (for example, chlorine atom, bromine atom, iodine atom), alkyl group (1 to 15, preferably 1 to 6). Linear, branched or cyclic alkyl groups having the following carbon atoms, for example, methyl group, ethyl group, n-propyl group, isopropyl group, t-butyl group, n-octyl group, 2-ethylhexyl group, cyclopropyl group, cyclopentyl Group), an alkenyl group (a linear, branched or cyclic alkenyl group having 2 to 10 carbon atoms, preferably 2 to 6 carbon atoms, such as a vinyl group, an allyl group), an alkynyl group (2 to 10, preferably Alkynyl group having 2 to 6 carbon atoms, for example, ethynyl group, propargyl group), aryl group (6 to 16, preferably 6 to 10 carbon atoms) Group, for example, phenyl group, naphthyl group), heterocyclic group (obtained by removing one hydrogen atom from 5- or 6-membered aromatic or non-aromatic heterocyclic compound, 1 to 12 , Preferably monovalent groups having 2 to 6 carbon atoms, such as 1-pyrazolyl group, 1-imidazolyl group, 2-furyl group, cyano group, hydroxyl group, nitro group, alkoxy group (1-10, Preferably a linear, branched or cyclic alkoxy group having 1 to 6 carbon atoms, for example, a methoxy group, an ethoxy group, an aryloxy group (6 to 12, preferably 6 to 8 carbon atoms) An oxy group, such as a phenoxy group, an acyl group (formyl group, 2-10, preferably an alkylcarbonyl group having 2-6 carbon atoms, or 7-12, preferably 7-9 carbon atoms. Arylcarbonyl group having, for example, acetyl group, pivaloyl group, benzoyl group), amino group (amino group, 1-10, preferably alkylamino group having 1-6 carbon atoms, 6-12, preferably Is an anilino group having 6 to 8 carbon atoms, or a heterocyclic amino group having 1 to 12, preferably 2 to 6 carbon atoms, such as an amino group, a methylamino group, an anilino group), a mercapto group An alkylthio group (an alkylthio group having 1 to 10, preferably 1 to 6 carbon atoms, such as a methylthio group, an ethylthio group), an arylthio group (6 to 12, preferably 6 to 8 carbon atoms). An arylthio group having, for example, a phenylthio group), a heterocyclic thio group (2 to 10, preferably 2 to 6 carbon atoms having a heterocyclic thio group, for example, - benzothiazolylthio group), an imido group (2 to 10, preferably an imido group having 4 to 8 carbon atoms, for example, N- succinimido group, N- phthalimido group).

Among these functional groups, those having a hydrogen atom may be further substituted with the above groups, for example, an alkyl group substituted with a hydroxyl group (for example, hydroxyethyl group), an alkyl group substituted with an alkoxy group (For example, methoxyethyl group), an alkyl group substituted with an aryl group (for example, benzyl group), an aryl group substituted with an alkyl group (for example, p-tolyl group), an aryloxy group substituted with an alkyl group ( Examples thereof include, but are not limited to, 2-methylphenoxy group.
In addition, when a functional group is further substituted, the carbon number mentioned above shall not include the carbon number of the further substituent. For example, a benzyl group is regarded as a C 1 alkyl group substituted with a phenyl group, and is not regarded as a C 7 alkyl group substituted with a phenyl group. The following description of the number of carbon atoms shall be similarly understood unless otherwise specified.

In the general formulas (IV) and (V), A ^{1 to} A ³ each represents a single bond or a divalent linking group. However, the case where both A ¹ and A ² in the general formula (IV) are single bonds is excluded. Examples of the divalent linking group include a linear, branched or cyclic alkylene group (C1-C12, preferably C1-C4 alkylene group such as a methylene group or ethylene group), an aralkylene group (carbon number). Examples thereof include aralkylene groups having 7 to 30 carbon atoms, preferably 7 to 13 carbon atoms, such as benzylidene groups, arylene groups (arylene groups having 6 to 30 carbon atoms, preferably 6 to 15 carbon atoms such as phenylene groups), and the like. These may further have a substituent, and examples of the substituent include the functional groups exemplified above as substituents represented by R, R ¹ and R ² . Examples thereof include, but are not limited to, an arylene group substituted with an alkyl group (for example, a xylylene group).

  In this invention, it is preferable that a polyamide resin (A) contains at least 1 sort (s) of the structural unit represented by either of the said general formula (III), (IV) or (V). Among these, from the viewpoint of improving the availability of raw materials and oxygen absorption, a carboxylic acid unit having tertiary hydrogen on the α-carbon (carbon atom adjacent to the carboxyl group) is more preferable, and is represented by the general formula (III). The structural unit is particularly preferred.

R in the general formula (III) is as described above. Among them, a substituted or unsubstituted alkyl group and a substituted or unsubstituted aryl group are more preferable, and a substituted or unsubstituted C 1-6 carbon atom is more preferable. An alkyl group and a substituted or unsubstituted aryl group having 6 to 10 carbon atoms are more preferred, and a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms and a substituted or unsubstituted phenyl group are particularly preferred.
Specific examples of preferable R include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, t-butyl group, 1-methylpropyl group, 2-methylpropyl group, hydroxymethyl group, 1- Examples thereof include, but are not limited to, a hydroxyethyl group, a mercaptomethyl group, a methylsulfanylethyl group, a phenyl group, a naphthyl group, a benzyl group, and a 4-hydroxybenzyl group. Among these, a methyl group, an ethyl group, an isopropyl group, a 2-methylpropyl group, and a benzyl group are more preferable.

Compounds that can constitute the structural unit represented by the general formula (III) include alanine, 2-aminobutyric acid, valine, norvaline, leucine, norleucine, tert-leucine, isoleucine, serine, threonine, cysteine, methionine, 2 -Although alpha-amino acids, such as phenylglycine, phenylalanine, tyrosine, histidine, tryptophan, proline, can be illustrated, it is not limited to these.
Moreover, as a compound which can comprise the structural unit represented by the said general formula (IV), (beta) -amino acids, such as 3-aminobutyric acid, can be illustrated, and the structural unit represented by the said general formula (V) is comprised. Examples of the compound that can be used include, but are not limited to, dicarboxylic acids such as methylmalonic acid, methylsuccinic acid, malic acid, and tartaric acid.
These may be any of D-form, L-form and racemate, or allo-form. Moreover, these can be used individually or in combination of 2 or more types.

  Among these, α-amino acids having tertiary hydrogen in the α carbon are particularly preferable from the viewpoints of availability of raw materials and oxygen absorption improvement. Among α-amino acids, alanine is most preferable from the viewpoints of ease of supply, inexpensive price, ease of polymerization, and low yellowness (YI) of the polymer. Since alanine has a relatively low molecular weight and a high copolymerization rate per 1 g of the polyamide resin (A), the oxygen absorption performance per 1 g of the polyamide resin (A) is good.

  Further, the purity of the compound that can constitute the tertiary hydrogen-containing carboxylic acid unit is 95% or more from the viewpoint of the influence on the polymerization such as the delay of the polymerization rate and the influence on the quality such as the yellowness of the polymer. Preferably, it is 98.5% or more, more preferably 99% or more. Further, sulfate ions and ammonium ions contained as impurities are preferably 500 ppm or less, more preferably 200 ppm or less, and still more preferably 50 ppm or less.

[Ω-aminocarboxylic acid unit]
In the present invention, when the polyamide resin (A) needs flexibility or the like, in addition to the diamine unit, the dicarboxylic acid unit and the tertiary hydrogen-containing carboxylic acid unit, the polyamide resin (A) You may further contain the omega-aminocarboxylic acid unit represented by Formula (X).

［前記一般式（Ｘ）中、ｐは２〜１８の整数を表す。］
前記ω−アミノカルボン酸単位の含有量は、ポリアミド樹脂（Ａ）の全構成単位中、好ましくは０．１〜４９．９モル％、より好ましくは３〜４０モル％、更に好ましくは５〜３５モル％である。ただし、前記のジアミン単位、ジカルボン酸単位、３級水素含有カルボン酸単位、及びω−アミノカルボン酸単位の合計は１００モル％を超えないものとする。
前記一般式（Ｘ）中、ｐは２〜１８の整数を表し、好ましくは３〜１６、より好ましくは４〜１４、更に好ましくは５〜１２である。

[In said general formula (X), p represents the integer of 2-18. ]
The content of the ω-aminocarboxylic acid unit is preferably 0.1 to 49.9 mol%, more preferably 3 to 40 mol%, still more preferably 5 to 35 in all the structural units of the polyamide resin (A). Mol%. However, the total of the diamine unit, dicarboxylic acid unit, tertiary hydrogen-containing carboxylic acid unit, and ω-aminocarboxylic acid unit shall not exceed 100 mol%.
In said general formula (X), p represents the integer of 2-18, Preferably it is 3-16, More preferably, it is 4-14, More preferably, it is 5-12.

  Examples of the compound that can constitute the ω-aminocarboxylic acid unit represented by the general formula (X) include ω-aminocarboxylic acid having 5 to 19 carbon atoms and lactam having 5 to 19 carbon atoms. Examples of the ω-aminocarboxylic acid having 5 to 19 carbon atoms include 6-aminohexanoic acid and 12-aminododecanoic acid, and examples of the lactam having 5 to 19 carbon atoms include ε-caprolactam and laurolactam. However, it is not limited to these. These can be used alone or in combination of two or more.

  The ω-aminocarboxylic acid unit preferably contains 6-aminohexanoic acid units and / or 12-aminododecanoic acid units in a total of 50 mol% or more in the ω-aminocarboxylic acid unit, and the content is More preferably, it is 70 mol% or more, More preferably, it is 80 mol% or more, More preferably, it is 90 mol% or more, Preferably it is 100 mol% or less.

[Polymerization degree of polyamide resin (A)]
The relative viscosity is used for the degree of polymerization of the polyamide resin (A). The preferred relative viscosity of the polyamide resin (A) is preferably 1.8 to 4.2, more preferably 1.9 to 4.0, and still more preferably 2 from the viewpoint of the strength and appearance of the molded product and molding processability. 0.0 to 3.8.
The relative viscosity here is 96% measured in the same manner as the dropping time (t) measured by dissolving a 1 g polyamide resin (A) in 100 mL of 96% sulfuric acid at 25 ° C. with a Canon Fenceke viscometer. It is the ratio of the drop time (t ₀ ) of sulfuric acid itself, and is represented by the following formula.
Relative viscosity = t / t ₀

[Terminal amino group concentration]
The oxygen absorption rate of the polyamide resin (A) and the oxidative deterioration of the polyamide resin (A) due to oxygen absorption can be controlled by changing the terminal amino group concentration of the polyamide resin (A). In the present invention, from the viewpoint of the balance between oxygen absorption rate and oxidative degradation, the terminal amino group concentration of the polyamide resin (A) is preferably in the range of 5 to 150 μeq / g, more preferably 10 to 100 μeq / g, and still more preferably 15 ˜80 μeq / g.

<Method for producing polyamide resin (A)>
The polyamide resin (A) includes a diamine component that can constitute the diamine unit, a dicarboxylic acid component that can constitute the dicarboxylic acid unit, and a tertiary hydrogen-containing carboxylic acid component that can constitute the tertiary hydrogen-containing carboxylic acid unit. And, if necessary, it can be produced by polycondensation with the ω-aminocarboxylic acid component that can constitute the ω-aminocarboxylic acid unit, and the degree of polymerization can be controlled by adjusting the polycondensation conditions and the like. it can. A small amount of monoamine or monocarboxylic acid may be added as a molecular weight modifier during polycondensation. Further, in order to suppress the polycondensation reaction and obtain a desired degree of polymerization, the ratio (molar ratio) between the diamine component and the carboxylic acid component constituting the polyamide resin (A) may be adjusted from 1.

  Examples of the polycondensation method of the polyamide resin (A) include, but are not limited to, a reactive extrusion method, a pressurized salt method, an atmospheric pressure dropping method, and a pressure dropping method. Moreover, the one where reaction temperature is as low as possible can suppress the yellowing and gelatinization of a polyamide resin (A), and the polyamide resin (A) of the stable property is obtained.

[Reactive extrusion method]
In the reactive extrusion method, a polyamide composed of a diamine component and a dicarboxylic acid component (polyamide corresponding to the precursor of the polyamide resin (A)) or a polyamide composed of a diamine component, a dicarboxylic acid component and an ω-aminocarboxylic acid component (polyamide resin (A And a tertiary hydrogen-containing carboxylic acid component are melt-kneaded with an extruder and reacted. This is a method of incorporating a tertiary hydrogen-containing carboxylic acid component into a polyamide skeleton by an amide exchange reaction. In order to sufficiently react, a screw suitable for reactive extrusion is used, and a twin screw extruder having a large L / D is used. It is preferable to use it. When producing a polyamide resin (A) containing a small amount of a tertiary hydrogen-containing carboxylic acid component, it is a simple method and suitable.

[Pressure salt method]
The pressurized salt method is a method of performing melt polycondensation under pressure using a nylon salt as a raw material. Specifically, after preparing a nylon salt aqueous solution consisting of a diamine component, a dicarboxylic acid component, a tertiary hydrogen-containing carboxylic acid component, and an ω-aminocarboxylic acid component as necessary, the aqueous solution is concentrated, Next, the temperature is raised under pressure, and polycondensation is performed while removing condensed water. While gradually returning the inside of the can to normal pressure, the temperature was raised to about the melting point of polyamide resin (A) + 10 ° C. and held, and further, the pressure was gradually reduced to −0.02 MPaG and kept at the same temperature. Continue polycondensation. When a constant stirring torque is reached, the inside of the can is pressurized to about 0.3 MPaG with nitrogen to recover the polyamide resin (A).
The pressurized salt method is useful when a volatile component is used as a monomer, and is a preferred polycondensation method when the copolymerization rate of the tertiary hydrogen-containing carboxylic acid component is high. It is suitable when the acid unit is contained in the structural unit of the polyamide resin (A) by 15 mol% or more. By using the pressurized salt method, transpiration of the tertiary hydrogen-containing carboxylic acid component can be prevented, and further, polycondensation between the tertiary hydrogen-containing carboxylic acid components can be suppressed, and the polycondensation reaction can proceed smoothly. Therefore, a polyamide resin (A) excellent in properties can be obtained.

[Normal pressure dropping method]
In the atmospheric pressure dropping method, a diamine component is continuously dropped into a mixture obtained by heating and melting a dicarboxylic acid component, a tertiary hydrogen-containing carboxylic acid component, and, if necessary, a ω-aminocarboxylic acid component under normal pressure. Then, polycondensation is performed while removing condensed water. The polycondensation reaction is performed while raising the temperature of the reaction system so that the reaction temperature does not fall below the melting point of the produced polyamide resin (A).
Compared with the pressurized salt method, the atmospheric pressure dropping method does not use water to dissolve the salt, so the yield per batch is large, and the reaction rate is not required for vaporization / condensation of raw material components. The process time can be shortened.

[Pressure drop method]
In the pressure drop method, first, a dicarboxylic acid component, a tertiary hydrogen-containing carboxylic acid component, and, if necessary, a ω-aminocarboxylic acid component are charged into a polycondensation can, and the components are stirred, melted and mixed. To prepare. Next, the diamine component is continuously dropped into the mixture while the inside of the can is preferably pressurized to about 0.3 to 0.4 MPaG, and polycondensation is performed while removing condensed water. At this time, the polycondensation reaction is performed while raising the temperature of the reaction system so that the reaction temperature does not fall below the melting point of the produced polyamide resin (A). When the set molar ratio is reached, the dropping of the diamine component is terminated, and while gradually raising the inside of the can to normal pressure, the temperature is raised to about the melting point of the polyamide resin (A) + 10 ° C. and held, and then −0.02 MPaG The pressure is gradually reduced until it is maintained at the same temperature, and the polycondensation is continued. When a constant stirring torque is reached, the inside of the can is pressurized to about 0.3 MPaG with nitrogen to recover the polyamide resin (A).
Like the pressurized salt method, the pressure dropping method is useful when a volatile component is used as a monomer, and is a preferred polycondensation method when the copolymerization rate of the tertiary hydrogen-containing carboxylic acid component is high. . In particular, it is suitable for producing a polyamide resin (A) containing 15 mol% or more of tertiary hydrogen-containing carboxylic acid units in all structural units of the polyamide resin (A). By using the pressure dropping method, the transpiration of the tertiary hydrogen-containing carboxylic acid component can be prevented, and further, the polycondensation between the tertiary hydrogen-containing carboxylic acid components can be suppressed, and the polycondensation reaction can proceed smoothly. Therefore, a polyamide resin (A) excellent in properties can be obtained. Furthermore, since the pressure drop method does not use water for dissolving the salt compared to the pressure salt method, the yield per batch is large, and the reaction time can be shortened as in the atmospheric pressure drop method. It is possible to obtain a polyamide resin (A) having a low yellowness, which can be suppressed.

[Process of increasing the degree of polymerization]
The polyamide resin (A) produced by the polycondensation method can be used as it is, but may be subjected to a step for further increasing the degree of polymerization. Further examples of the step of increasing the degree of polymerization include reactive extrusion in an extruder and solid phase polymerization. As a heating device used in solid phase polymerization, a continuous heating drying device, a tumble dryer, a conical dryer, a rotary drum heating device called a rotary dryer, etc., and a rotary blade inside a nauta mixer are provided. A conical heating device can be preferably used, but a known method and device can be used without being limited thereto. In particular, when solid-phase polymerization of the polyamide resin (A) is performed, the rotating drum type heating device in the above-described device can seal the inside of the system and perform polycondensation in a state where oxygen that causes coloring is removed. It is preferably used because it is easy to proceed.

[Phosphorus atom-containing compound, alkali metal compound]
In the polycondensation of the polyamide resin (A), it is preferable to add a phosphorus atom-containing compound from the viewpoint of promoting the amidation reaction.
Examples of the phosphorus atom-containing compound include phosphinic acid compounds such as dimethylphosphinic acid and phenylmethylphosphinic acid; hypophosphorous acid, sodium hypophosphite, potassium hypophosphite, lithium hypophosphite, magnesium hypophosphite, Diphosphite compounds such as calcium hypophosphite and ethyl hypophosphite; phosphonic acid, sodium phosphonate, potassium phosphonate, lithium phosphonate, magnesium phosphonate, calcium phosphonate, phenylphosphonic acid, ethylphosphonic acid, phenylphosphone Phosphonic acid compounds such as sodium phosphate, potassium phenylphosphonate, lithium phenylphosphonate, diethyl phenylphosphonate, sodium ethylphosphonate, potassium ethylphosphonate; phosphonous acid, sodium phosphonite, lithium phosphonite, Phosphonous compounds such as potassium sulfonate, magnesium phosphonite, calcium phosphonite, phenylphosphonite, sodium phenylphosphonite, potassium phenylphosphonite, lithium phenylphosphonite, ethyl phenylphosphonite; Phosphorous acid, sodium hydrogen phosphite, sodium phosphite, lithium phosphite, potassium phosphite, magnesium phosphite, calcium phosphite, triethyl phosphite, triphenyl phosphite, pyrophosphorous acid, etc. A phosphoric acid compound etc. are mentioned.
Among these, hypophosphite metal salts such as sodium hypophosphite, potassium hypophosphite, lithium hypophosphite and the like are particularly preferable because they are highly effective in promoting amidation reaction and excellent in anti-coloring effect. In particular, sodium hypophosphite is preferred. In addition, the phosphorus atom containing compound which can be used by this invention is not limited to these compounds.
The addition amount of the phosphorus atom-containing compound is preferably 0.1 to 1000 ppm, more preferably 1 to 600 ppm, still more preferably 5 to 400 ppm in terms of the phosphorus atom concentration in the polyamide resin (A). If it is 0.1 ppm or more, the polyamide resin (A) is difficult to be colored during the polymerization, and the transparency becomes high. If it is 1000 ppm or less, the polyamide resin (A) is hardly gelled, and it is possible to reduce the mixing of fish eyes considered to be caused by the phosphorus atom-containing compound into the molded product, so that the appearance of the molded product is improved.

Moreover, it is preferable to add an alkali metal compound in combination with the phosphorus atom-containing compound in the polycondensation system of the polyamide resin (A). In order to prevent coloring of the polyamide resin (A) during the polycondensation, it is necessary to make a sufficient amount of the phosphorus atom-containing compound present. However, in some cases, the polyamide resin (A) may be gelled. In order to adjust the amidation reaction rate, it is preferable to coexist an alkali metal compound.
As the alkali metal compound, alkali metal hydroxide, alkali metal acetate, alkali metal carbonate, alkali metal alkoxide, and the like are preferable. Specific examples of the alkali metal compound that can be used in the present invention include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, lithium acetate, sodium acetate, potassium acetate, rubidium acetate, cesium acetate. Sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, potassium methoxide, lithium methoxide, sodium carbonate and the like, but can be used without being limited to these compounds. The ratio (molar ratio) between the phosphorus atom-containing compound and the alkali metal compound is such that the phosphorus atom-containing compound / alkali metal compound = 1.0 / 0.05 to from the viewpoint of controlling the polymerization rate and reducing the yellowness. The range of 1.0 / 1.5 is preferable, more preferably 1.0 / 0.1 to 1.0 / 1.2, and still more preferably 1.0 / 0.2 to 1.0 / 1. 1.

1-2. Additive (C)
The oxygen absorption barrier layer of the present invention may further contain an additive (C) as necessary in addition to the polyamide resin (A) described above. One type of additive (C) may be used, or a combination of two or more types may be used. The content of the additive (C) in the oxygen absorption barrier layer is preferably 10% by mass or less, more preferably 5% by mass or less, although it depends on the type of additive.

[Anti-whitening agent]
In the present invention, it is preferable to add a diamide compound and / or a diester compound to the polyamide resin (A) as a suppression of whitening after the hot water treatment or after a long period of time. Diamide compounds and diester compounds are effective in suppressing whitening due to precipitation of oligomers. A diamide compound and a diester compound may be used alone or in combination.

  The diamide compound used in the present invention is preferably a diamide compound obtained from an aliphatic dicarboxylic acid having 8 to 30 carbon atoms and a diamine having 2 to 10 carbon atoms. When the aliphatic dicarboxylic acid has 8 or more carbon atoms and the diamine has 2 or more carbon atoms, a whitening prevention effect can be expected. In addition, when the aliphatic dicarboxylic acid has 30 or less carbon atoms and the diamine has 10 or less carbon atoms, uniform dispersion in the oxygen-absorbing barrier layer is good. The aliphatic dicarboxylic acid may have a side chain or a double bond, but a linear saturated aliphatic dicarboxylic acid is preferred. One kind of diamide compound may be used, or two or more kinds may be used in combination.

Examples of the aliphatic dicarboxylic acid include stearic acid (C18), eicosanoic acid (C20), behenic acid (C22), montanic acid (C28), and triacontanoic acid (C30). Examples of the diamine include ethylenediamine, butylenediamine, hexanediamine, xylylenediamine, and bis (aminomethyl) cyclohexane. A diamide compound obtained by combining these is preferred.
A diamide compound obtained from a diamine composed mainly of an aliphatic dicarboxylic acid having 8 to 30 carbon atoms and mainly ethylenediamine, or a diamide compound obtained from an aliphatic dicarboxylic acid mainly composed of montanic acid and a diamine having 2 to 10 carbon atoms is particularly preferred. Is a diamide compound obtained from an aliphatic dicarboxylic acid mainly composed of stearic acid and a diamine mainly composed of ethylenediamine.

The diester compound used in the present invention is preferably a diester compound obtained from an aliphatic dicarboxylic acid having 8 to 30 carbon atoms and a diol having 2 to 10 carbon atoms. When the aliphatic dicarboxylic acid has 8 or more carbon atoms and the diol has 2 or more carbon atoms, an effect of preventing whitening can be expected. Further, when the aliphatic dicarboxylic acid has 30 or less carbon atoms and the diol has 10 or less carbon atoms, uniform dispersion in the oxygen-absorbing barrier layer is good. The aliphatic dicarboxylic acid may have a side chain or a double bond, but a linear saturated aliphatic dicarboxylic acid is preferred. One type of diester compound may be used, or two or more types may be used in combination.
Examples of the aliphatic dicarboxylic acid include stearic acid (C18), eicosanoic acid (C20), behenic acid (C22), montanic acid (C28), and triacontanoic acid (C30). Examples of the diol include ethylene glycol, propanediol, butanediol, hexanediol, xylylene glycol, and cyclohexanedimethanol. A diester compound obtained by combining these is preferred.
Particularly preferred are diester compounds obtained from an aliphatic dicarboxylic acid mainly composed of montanic acid and a diol mainly composed of ethylene glycol and / or 1,3-butanediol.

  In the present invention, the amount of the diamide compound and / or diester compound added is preferably 0.005 to 0.5% by mass, more preferably 0.05 to 0.5% by mass, and still more preferably in the oxygen absorption barrier layer. It is 0.12-0.5 mass%. A synergistic effect of preventing whitening can be expected by adding 0.005% by mass or more to the oxygen absorption barrier layer and using it together with the crystallization nucleating agent. Moreover, it becomes possible to keep the fog value of the molded object obtained by shape | molding the polyamide resin (A) of this invention low as the addition amount is 0.5 mass% or less in an oxygen absorption barrier layer.

[Layered silicate]
In the present invention, the oxygen absorption barrier layer may contain a layered silicate. By adding the layered silicate, not only oxygen gas barrier properties but also barrier properties against gases such as carbon dioxide gas can be imparted to the multilayer sheet.

  The layered silicate is a 2-octahedral or 3-octahedral layered silicate having a charge density of 0.25 to 0.6. Examples of the 2-octahedral type include montmorillonite, beidellite, and the like. Examples of the octahedron type include hectorite and saponite. Among these, montmorillonite is preferable.

  The layered silicate is preferably obtained by expanding an interlayer of the layered silicate by previously bringing an organic swelling agent such as a polymer compound or an organic compound into contact with the layered silicate. As the organic swelling agent, a quaternary ammonium salt can be preferably used. Preferably, a quaternary ammonium salt having at least one alkyl group or alkenyl group having 12 or more carbon atoms is used.

  Specific examples of organic swelling agents include trimethyl dodecyl ammonium salt, trimethyl tetradecyl ammonium salt, trimethyl hexadecyl ammonium salt, trimethyl octadecyl ammonium salt, trimethyl alkyl decyl ammonium salt, trimethyl alkyl decyl ammonium salt; trimethyl octadecenyl ammonium salt Trimethylalkenylammonium salts such as trimethyloctadecadienylammonium salt; triethylalkylammonium salts such as triethyldodecylammonium salt, triethyltetradecylammonium salt, triethylhexadecylammonium salt, triethyloctadecylammonium salt; tributyldodecylammonium salt, tributyltetradecyl Ammonium salt, tributyl hexadecyl ammonium salt, tri Tributylalkylammonium salts such as tiloctadecylammonium salt; dimethyldialkylammonium salts such as dimethyldidodecylammonium salt, dimethylditetradecylammonium salt, dimethyldihexadecylammonium salt, dimethyldioctadecylammonium salt, dimethylditallowammonium salt; dimethyl Dioctadecenyl ammonium salt, dimethyl dialkenyl ammonium salt such as dimethyl dioctadecadienyl ammonium salt; diethyl didodecyl ammonium salt, diethyl ditetradecyl ammonium salt, diethyl dihexadecyl ammonium salt, diethyl dioctadecyl ammonium salt, etc. Diethyl dialkyl ammonium salt; dibutyl didodecyl ammonium salt, dibutyl ditetradecyl ammonium salt, dibu Dibutyl dialkyl ammonium salts such as rudihexadecyl ammonium salt and dibutyl dioctadecyl ammonium salt; Methyl benzyl dialkyl ammonium salts such as methyl benzyl dihexadecyl ammonium salt; Dibenzyl dialkyl ammonium salts such as dibenzyl dihexadecyl ammonium salt; Tridodecyl Trialkylmethylammonium salts such as methylammonium salt, tritetradecylmethylammonium salt, trioctadecylmethylammonium salt; trialkylethylammonium salts such as tridodecylethylammonium salt; trialkylbutylammonium salts such as tridodecylbutylammonium salt; 4-amino-n-butyric acid, 6-amino-n-caproic acid, 8-aminocaprylic acid, 10-aminodecanoic acid, 12-aminodode Examples include ω-amino acids such as canic acid, 14-aminotetradecanoic acid, 16-aminohexadecanoic acid, and 18-aminooctadecanoic acid. In addition, hydroxyl group and / or ether group-containing ammonium salts, among them, methyl dialkyl (PAG) ammonium salt, ethyl dialkyl (PAG) ammonium salt, butyl dialkyl (PAG) ammonium salt, dimethyl bis (PAG) ammonium salt, diethyl bis (PAG) ) Ammonium salt, dibutyl bis (PAG) ammonium salt, methyl alkyl bis (PAG) ammonium salt, ethyl alkyl bis (PAG) ammonium salt, butyl alkyl bis (PAG) ammonium salt, methyl tri (PAG) ammonium salt, ethyl tri (PAG) ammonium Salt, butyltri (PAG) ammonium salt, tetra (PAG) ammonium salt (wherein alkyl is carbon number such as dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl, etc.) A quaternary ammonium containing at least one alkylene glycol residue such as a polyalkylene glycol residue, preferably a polyethylene glycol residue or a polypropylene glycol residue having 20 or less carbon atoms). Salts can also be used as organic swelling agents. Among them, trimethyldodecyl ammonium salt, trimethyl tetradecyl ammonium salt, trimethyl hexadecyl ammonium salt, trimethyl octadecyl ammonium salt, dimethyl didodecyl ammonium salt, dimethyl ditetradecyl ammonium salt, dimethyl dihexadecyl ammonium salt, dimethyl dioctadecyl ammonium salt, dimethyl A ditallow ammonium salt is preferred. These organic swelling agents can be used alone or as a mixture of a plurality of types.

  In this invention, what added 0.5-8 mass% of layered silicate processed with the organic swelling agent to an oxygen absorption barrier layer is used preferably, More preferably, it is 1-6 mass%, More preferably, it is 2 5% by mass. If the amount of layered silicate added is 0.5% by mass or more, the effect of improving the gas barrier property is sufficiently obtained, and if it is 8% by mass or less, pinholes are generated due to deterioration of the flexibility of the oxygen absorption barrier layer. Such problems are unlikely to occur.

  In the oxygen absorption barrier layer, the layered silicate is preferably uniformly dispersed without locally agglomerating. The uniform dispersion here means that the layered silicate is separated into a flat plate in the oxygen absorption barrier layer, and 50% or more of them have an interlayer distance of 5 nm or more. Here, the interlayer distance refers to the distance between the centers of gravity of the flat objects. The larger the distance, the better the dispersion state, the better the appearance such as transparency, and the better the gas barrier properties such as oxygen and carbon dioxide.

[Oxidation reaction accelerator]
In order to further enhance the oxygen absorption performance of the oxygen absorption barrier layer, a conventionally known oxidation reaction accelerator may be added as long as the effects of the present invention are not impaired. The oxidation reaction accelerator can enhance the oxygen absorption performance of the oxygen absorption barrier layer by promoting the oxygen absorption performance of the polyamide resin (A). Examples of the oxidation reaction accelerator include Group VIII metals such as iron, cobalt and nickel, Group I metals such as copper and silver, Group IV metals such as tin, titanium and zirconium, Group V of vanadium, Examples thereof include low-valent inorganic or organic acid salts of Group VI metals such as chromium and Group VII metals such as manganese, or complex salts of the above transition metals. Among these, a cobalt salt excellent in an oxygen reaction promoting effect or a combination of a cobalt salt and a manganese salt is preferable.
In the present invention, the addition amount of the oxygen reaction accelerator is preferably 10 to 800 ppm, more preferably 50 to 600 ppm, and still more preferably 100 to 400 ppm as a metal atom concentration in the resin composition.

[Oxygen absorber]
In order to further enhance the oxygen absorption performance of the oxygen absorption barrier layer, a conventionally known oxygen absorbent may be added within a range not impairing the effects of the present invention. The oxygen absorbent can enhance the oxygen absorption performance of the oxygen absorption barrier layer by imparting oxygen absorption performance to the oxygen absorption barrier layer separately from the oxygen absorption performance of the polyamide resin (A). Examples of the oxygen absorbent include oxidizable organic compounds typified by compounds having a carbon-carbon double bond in the molecule, such as vitamin C, vitamin E, butadiene, and isoprene.
In the present invention, the amount of oxygen absorbent added is preferably 0.01 to 5% by mass, more preferably 0.1 to 4% by mass, and still more preferably 0.5 to 3% by mass in the oxygen absorption barrier layer. is there.

[Anti-gelling / Fish Eye Reducing Agent]
In the present invention, it is preferable to add one or more carboxylates selected from sodium acetate, calcium acetate, magnesium acetate, calcium stearate, magnesium stearate, sodium stearate and derivatives thereof. Examples of the derivative include 12-hydroxystearic acid metal salts such as calcium 12-hydroxystearate, magnesium 12-hydroxystearate, and sodium 12-hydroxystearate. By adding the carboxylates, it is possible to prevent the gelation of the polyamide resin (A) that occurs during the molding process and to reduce fish eyes in the molded article, thereby improving the suitability of the molding process.

The addition amount of the carboxylates is preferably 400 to 10,000 ppm, more preferably 800 to 5000 ppm, and still more preferably 1000 to 3000 ppm as the concentration in the oxygen absorption barrier layer. If it is 400 ppm or more, the thermal deterioration of the polyamide resin (A) can be suppressed, and gelation can be prevented. Moreover, if it is 10000 ppm or less, a polyamide resin (A) will not raise | generate a shaping | molding defect, and neither coloring nor whitening will occur. It is speculated that the presence of carboxylates that are basic substances in the melted polyamide resin (A) delays the modification of the polyamide resin (A) by heat and suppresses the formation of a gel that is considered to be the final modified product. The
The carboxylates described above are excellent in handling properties, and among them, metal stearate is preferable because it is inexpensive and has an effect as a lubricant, and can stabilize the molding process. Further, the shape of the carboxylate is not particularly limited, but when the powder and the smaller particle size are dry-mixed, it is easy to uniformly disperse in the oxygen absorption barrier layer. Is preferably 0.2 mm or less.
Furthermore, it is preferable to use sodium acetate having a high metal salt concentration per gram as a more effective gelling prevention, fish eye reduction, and further a kogation prevention formulation. When sodium acetate is used, it may be dry mixed with the polyamide resin (A) and molded, but from the viewpoint of handling properties and reduction of acetic acid odor, a masterbatch comprising the polyamide resin (A) and sodium acetate is prepared. It is preferable to dry-mix with the polyamide resin (A) for molding. Since it is easy to disperse | distribute sodium acetate used for a masterbatch uniformly to a polyamide resin (A), the particle size is 0.2 mm or less, and 0.1 mm or less is more preferable.

[Antioxidant]
In the present invention, it is preferable to add an antioxidant from the viewpoint of controlling oxygen absorption performance and suppressing deterioration of mechanical properties. Examples of the antioxidant include copper-based antioxidants, hindered phenol-based antioxidants, hindered amine-based antioxidants, phosphorus-based antioxidants, and thio-based antioxidants. Antioxidants and phosphorus antioxidants are preferred.

  Specific examples of the hindered phenol antioxidant include triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate, 4,4′-butylidenebis (3-methyl- 6-t-butylphenol), 1,6-hexanediol-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2,4-bis- (n-octylthio) -6 (4-Hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3 5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2-thiobis (4-methyl-6-1-butylphenol), N, N′-hexamethylenebis (3,5-di-t-butyl) -4-hydroxy-hydroxycinnamamide), 3,5-di-t-butyl-4-hydroxy-benzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris (3,5 -Di-butyl-4-hydroxybenzyl) benzene, ethyl calcium bis (3,5-di-t-butyl-4-hydroxybenzylsulfonate, tris- (3,5-di-t-butyl-4-hydroxybenzyl) ) -Isocyanurate, 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol , Stearyl-β- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2′-methylenebis- (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis -(4-ethyl-6-t-butylphenol), 4,4'-thiobis- (3-methyl-6-t-butylphenol), octylated diphenylamine, 2,4-bis [(octylthio) methyl] -O- Cresol, isooctyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 4,4′-butylidenebis (3-methyl-6-tert-butylphenol, 3,9-bis [1,1 -Dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] 2,4,8,10-tetraoxa Pyro [5,5] undecane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3 , 5-di-t-butyl-4-hydroxybenzyl) benzene, bis [3,3′-bis- (4′-hydroxy-3′-T-butylphenyl) butyric acid] glycol ester, 1,3, 5-tris (3 ′, 5′-di-t-butyl-4′-hydroxybenzyl) -sec-triazine-2,4,6- (1H, 3H, 5H) trione, d-α-tocopherol, etc. It is done. These can be used alone or as a mixture thereof. Specific examples of commercially available hindered phenol compounds include Irganox 1010 and Irganox 1098 manufactured by BASF (both are trade names).

  Specific examples of phosphorus antioxidants include triphenyl phosphite, trioctadecyl phosphite, tridecyl phosphite, trinonylphenyl phosphite, diphenylisodecyl phosphite, bis (2,6-di-tert-butyl- 4-methylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, tris (2,4-di-tert-butylphenyl) phosphite, distearyl pentaerythritol Examples include organic phosphorus compounds such as diphosphite, tetra (tridecyl-4,4′-isopropylidene diphenyl diphosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite. Is alone or It can be used in a mixture of these.

  The content of the antioxidant can be used without particular limitation as long as it does not impair the various performances of the composition, but it is preferable in the oxygen-absorbing barrier layer from the viewpoint of controlling the oxygen-absorbing performance and suppressing deterioration of mechanical properties. Is 0.001 to 3 mass%, more preferably 0.01 to 1 mass%.

[Other additives]
Depending on the required application and performance, the oxygen-absorbing barrier layer has a lubricant, matting agent, heat stabilizer, weathering stabilizer, ultraviolet absorber, plasticizer, flame retardant, antistatic agent, anti-coloring agent, crystal An additive such as a nucleating agent may be added. These additives can be added as necessary within a range not impairing the effects of the present invention.

2. Layer mainly composed of resin (B) (B)
The layer (B) in the present invention is a layer mainly composed of the resin (B). Here, “main component” means that the layer (B) contains the resin (B) in an amount of 70% by mass or more, preferably 80% by mass or more, more preferably 90 to 100% by mass. . The layer (B) may contain the additive (C) in addition to the resin (B) depending on the desired performance and the like.
The multilayer sheet of the present invention may have a plurality of layers (B), and the configuration of the plurality of layers (B) may be the same as or different from each other.
The thickness of the layer (B) can be appropriately determined according to the use, and from the viewpoint of ensuring various physical properties such as flexibility required for the multilayer sheet, it is preferably 5-1000 μm, more preferably 50- It is 900 micrometers, More preferably, it is 100-800 micrometers.

2-1. Resin (B)
In the present invention, any resin can be used as the resin (B) and is not particularly limited. As the resin (B), for example, a thermoplastic resin can be used, and specific examples thereof include polyolefin, polyester, polyamide, ethylene-vinyl alcohol copolymer, and plant-derived resin. In the present invention, the resin (B) preferably contains at least one selected from the group consisting of these resins.
Among these, a resin having high oxygen barrier properties such as polyester, polyamide, and ethylene-vinyl alcohol copolymer is more preferable in order to effectively exhibit the oxygen absorption effect.

[Polyolefin]
Specific examples of polyolefin include olefins such as polyethylene (low density polyethylene, medium density polyethylene, high density polyethylene, linear (linear) low density polyethylene), polypropylene, polybutene-1, and poly-4-methylpentene-1. Homopolymer; Copolymer of ethylene and α-olefin such as ethylene-propylene random copolymer, ethylene-propylene block copolymer, ethylene-propylene-polybutene-1 copolymer, ethylene-cyclic olefin copolymer Ethylene-α, β-unsaturated carboxylic acid copolymer such as ethylene- (meth) acrylic acid copolymer, ethylene-α, β-unsaturated carboxylic acid such as ethylene- (meth) acrylic acid ethyl copolymer Ester copolymer, ionic cross-linked product of ethylene-α, β-unsaturated carboxylic acid copolymer, ethylene - Other ethylene copolymers such as vinyl acetate copolymer; may be mentioned graft-modified polyolefin grafted modifying these polyolefins with an acid anhydride such as maleic anhydride.

[polyester]
In the present invention, the polyester is composed of one or more selected from polycarboxylic acids containing dicarboxylic acids and ester-forming derivatives thereof, and one or more selected from polyhydric alcohols containing glycol. Or a hydroxycarboxylic acid and an ester-forming derivative thereof, or a cyclic ester.

  Examples of dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, tetradecanedicarboxylic acid, hexadecanedicarboxylic acid, 3- Exemplified as cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 2,5-norbornanedicarboxylic acid, dimer acid, etc. Saturated aliphatic dicarboxylic acids or ester-forming derivatives thereof, unsaturated aliphatic dicarboxylic acids exemplified by fumaric acid, maleic acid, itaconic acid or the like, or ester-forming derivatives thereof, orthophthalic acid, isophthalic acid, terephthalic acid 1,3-na Taleenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, 4,4′- Aromatic dicarboxylic acids exemplified by biphenylsulfone dicarboxylic acid, 4,4′-biphenyl ether dicarboxylic acid, 1,2-bis (phenoxy) ethane-p, p′-dicarboxylic acid, anthracene dicarboxylic acid, etc. or ester formation thereof Metal, exemplified by 5-sodium sulfoisophthalic acid, 2-sodium sulfoterephthalic acid, 5-lithium sulfoisophthalic acid, 2-lithium sulfoterephthalic acid, 5-potassium sulfoisophthalic acid, 2-potassium sulfoterephthalic acid, etc. Sulfonate group-containing aromatic dicarboxylic acid or Such lower alkyl esters thereof derivative.

  Among the above dicarboxylic acids, the use of terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid is particularly preferable in terms of the physical properties of the resulting polyester, and other dicarboxylic acids may be copolymerized as necessary. .

  As polyvalent carboxylic acids other than these dicarboxylic acids, ethanetricarboxylic acid, propanetricarboxylic acid, butanetetracarboxylic acid, pyromellitic acid, trimellitic acid, trimesic acid, 3,4,3 ′, 4′-biphenyltetracarboxylic acid, And ester-forming derivatives thereof.

  As glycols, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, triethylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 2,3-butylene glycol, 1,4 -Butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediethanol, 1,10-decamethylene glycol, 1,12-dodecanediol, polyethylene glycol, polytrimethyl Aliphatic glycol, hydroquinone, 4,4′-dihydroxybisphenol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-bis (β-hydroxyethoxyphenyl) exemplified by tylene glycol and polytetramethylene glycol ) Sulfone, bis (p-hydroxyphenyl) ether, bis (p-hydroxyphenyl) sulfone, bis (p-hydroxyphenyl) methane, 1,2-bis (p-hydroxyphenyl) ethane, bisphenol A, bisphenol C, 2 , 5-naphthalenediol, and aromatic glycols exemplified by glycols obtained by adding ethylene oxide to these glycols.

  Among the above glycols, it is particularly preferable to use ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, and 1,4-cyclohexanedimethanol as the main component. Examples of polyhydric alcohols other than these glycols include trimethylolmethane, trimethylolethane, trimethylolpropane, pentaerythritol, glycerol, hexanetriol, and the like. Examples of hydroxycarboxylic acids include lactic acid, citric acid, malic acid, tartaric acid, hydroxyacetic acid, 3-hydroxybutyric acid, p-hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid, 4-hydroxycyclohexanecarboxylic acid, or these And ester-forming derivatives thereof.

  Examples of the cyclic ester include ε-caprolactone, β-propiolactone, β-methyl-β-propiolactone, δ-valerolactone, glycolide, and lactide.

  Examples of ester-forming derivatives of polyvalent carboxylic acids and hydroxycarboxylic acids include these alkyl esters, acid chlorides, acid anhydrides and the like.

  The polyester used in the present invention is preferably a polyester in which the main acid component is terephthalic acid or an ester-forming derivative thereof or naphthalenedicarboxylic acid or an ester-forming derivative thereof, and the main glycol component is alkylene glycol.

  The polyester in which the main acid component is terephthalic acid or an ester-forming derivative thereof is preferably a polyester containing 70 mol% or more of terephthalic acid or an ester-forming derivative thereof in total with respect to the total acid component. A polyester containing 80 mol% or more is preferable, and a polyester containing 90 mol% or more is more preferable. Similarly, the polyester in which the main acid component is naphthalenedicarboxylic acid or an ester-forming derivative thereof is also preferably a polyester containing 70 mol% or more of naphthalenedicarboxylic acid or an ester-forming derivative thereof, more preferably 80 Polyesters containing at least mol%, more preferably polyesters containing at least 90 mol%.

  Examples of the naphthalenedicarboxylic acid or ester-forming derivative thereof used in the present invention include 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid exemplified in the above dicarboxylic acids, 2, 6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, or ester-forming derivatives thereof are preferred.

  The polyester whose main glycol component is an alkylene glycol is preferably a polyester containing 70 mol% or more of the total amount of alkylene glycol with respect to all glycol components, more preferably a polyester containing 80 mol% or more, More preferably, it is a polyester containing 90 mol% or more. The alkylene glycol here may contain a substituent or an alicyclic structure in the molecular chain.

  The copolymer components other than the terephthalic acid / ethylene glycol are isophthalic acid, 2,6-naphthalenedicarboxylic acid, diethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,2-propanediol, 1,3-propane. It is preferably at least one selected from the group consisting of diol and 2-methyl-1,3-propanediol in order to achieve both transparency and moldability, particularly isophthalic acid, diethylene glycol, neopentyl glycol, More preferably, it is at least one selected from the group consisting of 1,4-cyclohexanedimethanol.

  A preferred example of the polyester used in the present invention is a polyester whose main repeating unit is composed of ethylene terephthalate, more preferably a linear polyester containing 70 mol% or more of ethylene terephthalate units, and still more preferably an ethylene terephthalate unit. A linear polyester containing 80 mol% or more is preferable, and a linear polyester containing 90 mol% or more of ethylene terephthalate units is particularly preferable.

  Another preferred example of the polyester used in the present invention is a polyester in which the main repeating unit is composed of ethylene-2,6-naphthalate, more preferably 70 mol% or more of ethylene-2,6-naphthalate unit. It is a linear polyester, more preferably a linear polyester containing 80 mol% or more of ethylene-2,6-naphthalate units, and particularly preferable is a linear polyester containing 90 mol% or more of ethylene-2,6-naphthalate units. Polyester.

  Other preferable examples of the polyester used in the present invention include linear polyesters containing 70 mol% or more of propylene terephthalate units, linear polyesters containing 70 mol% or more of propylene naphthalate units, and 1,4-cyclohexanedimethylene terephthalate. A linear polyester containing 70 mol% or more of units, a linear polyester containing 70 mol% or more of butylene naphthalate units, or a linear polyester containing 70 mol% or more of butylene terephthalate units.

  In particular, the composition of the whole polyester is a combination of terephthalic acid / isophthalic acid // ethylene glycol, terephthalic acid // ethylene glycol / 1,4-cyclohexanedimethanol, and terephthalic acid // ethylene glycol / neopentyl glycol. This is preferable in order to satisfy both the moldability and the moldability. Needless to say, a small amount (5 mol% or less) of diethylene glycol produced by dimerization of ethylene glycol may be included in the esterification (transesterification) reaction or polycondensation reaction.

  Other preferable examples of the polyester used in the present invention include polyglycolic acid obtained by polycondensation of glycolic acid or methyl glycolate or ring-opening polycondensation of glycolide. This polyglycolic acid may be copolymerized with other components such as lactide.

[polyamide]
The polyamide used in the present invention (herein, “polyamide” is not “polyamide resin (A)” in the present invention) is a polyamide mainly composed of units derived from lactam or aminocarboxylic acid, or Aliphatic polyamides whose main constituent units are units derived from aliphatic diamines and aliphatic dicarboxylic acids, partially aromatic polyamides whose main constituent units are units derived from aliphatic diamines and aromatic dicarboxylic acids, aromatic Examples thereof include partially aromatic polyamides having a unit derived from a diamine and an aliphatic dicarboxylic acid as a main constituent unit, and monomer units other than the main constituent unit may be copolymerized as necessary.

  Examples of the lactam or aminocarboxylic acid include lactams such as ε-caprolactam and laurolactam, aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid, and aromatic aminocarboxylic acids such as para-aminomethylbenzoic acid. .

  As the aliphatic diamine, an aliphatic diamine having 2 to 12 carbon atoms or a functional derivative thereof can be used. Furthermore, an alicyclic diamine may be used. The aliphatic diamine may be a linear aliphatic diamine or a branched chain aliphatic diamine. Specific examples of such linear aliphatic diamines include ethylenediamine, 1-methylethylenediamine, 1,3-propylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, Examples include aliphatic diamines such as nonamethylenediamine, decamethylenediamine, undecamethylenediamine, and dodecamethylenediamine. Specific examples of the alicyclic diamine include cyclohexanediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, and the like.

  Moreover, as said aliphatic dicarboxylic acid, linear aliphatic dicarboxylic acid and alicyclic dicarboxylic acid are preferable, and also linear aliphatic dicarboxylic acid which has a C4-C12 alkylene group is especially preferable. Examples of such linear aliphatic dicarboxylic acids include adipic acid, sebacic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, undecanoic acid, undecadioic acid, dodecanedioic acid, dimer Examples thereof include acids and functional derivatives thereof. Examples of the alicyclic dicarboxylic acid include alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid.

  Examples of the aromatic diamine include metaxylylenediamine, paraxylylenediamine, para-bis (2-aminoethyl) benzene, and the like.

  Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, diphenoxyethanedicarboxylic acid, and functional derivatives thereof. It is done.

  Specific polyamides include polyamide 4, polyamide 6, polyamide 10, polyamide 11, polyamide 12, polyamide 4, 6, polyamide 6, 6, polyamide 6, 10, polyamide 6T, polyamide 9T, polyamide 6IT, polymetaxylylene azide. Pamide (polyamide MXD6), isophthalic acid copolymer polymetaxylylene adipamide (polyamide MXD6I), polymetaxylylene sebamide (polyamide MXD10), polymetaxylylene decanamide (polyamide MXD12), poly 1,3-bis (Aminomethyl) cyclohexane adipamide (polyamide BAC6), polyparaxylylene sebacamide (polyamide PXD10) and the like. More preferable polyamides include polyamide 6, polyamide MXD6, and polyamide MXD6I.

  Further, as a copolymerization component of the polyamide, a polyether having at least one terminal amino group or a terminal carboxyl group and a number average molecular weight of 2000 to 20000, or an organic carboxylate of the polyether having the terminal amino group, or An amino salt of a polyether having a terminal carboxyl group can also be used. Specific examples include bis (aminopropyl) poly (ethylene oxide) (polyethylene glycol having a number average molecular weight of 2000 to 20000).

  The partially aromatic polyamide may contain a structural unit derived from a polybasic carboxylic acid having 3 or more bases such as trimellitic acid and pyromellitic acid within a substantially linear range.

  The polyamide is basically a conventionally known melt polycondensation method in the presence of water or a melt polycondensation method in the absence of water, or a polyamide obtained by these melt polycondensation methods. It can be manufactured by a method or the like. The melt polycondensation reaction may be performed in one step or may be performed in multiple steps. These may be comprised from a batch-type reaction apparatus, and may be comprised from the continuous-type reaction apparatus. The melt polycondensation step and the solid phase polymerization step may be operated continuously or may be operated separately.

[Ethylene-vinyl alcohol copolymer]
Although it does not specifically limit as an ethylene vinyl alcohol copolymer used by this invention, Preferably it is 15-60 mol%, More preferably, it is 20-55 mol%, More preferably, it is 29-44 mol%, The degree of saponification of the vinyl acetate component is preferably 90 mol% or more, more preferably 95 mol% or more.
Further, the ethylene vinyl alcohol copolymer has a smaller amount of an α-olefin such as propylene, isobutene, α-octene, α-dodecene, α-octadecene, and unsaturated carboxylic acid as long as the effects of the present invention are not adversely affected. Alternatively, a comonomer such as a salt thereof, a partial alkyl ester, a complete alkyl ester, a nitrile, an amide, an anhydride, an unsaturated sulfonic acid or a salt thereof may be contained.

[Plant-derived resin]
Specific examples of the plant-derived resin include a portion overlapping with the above resin, but are not particularly limited, and examples thereof include aliphatic polyester-based biodegradable resins other than various known petroleum materials. Examples of the aliphatic polyester-based biodegradable resin include poly (α-hydroxy acids) such as polyglycolic acid (PGA) and polylactic acid (PLA); polybutylene succinate (PBS), polyethylene succinate (PES), and the like. And polyalkylene alkanoates.

[Other resins]
Various conventionally known resins may be added as long as the object of the present invention is not impaired. For example, from the viewpoint of imparting impact resistance, pinhole resistance, flexibility and adhesiveness, polyolefins such as polyethylene and polypropylene and their various modified products, polyolefin elastomers, polyamide elastomers, styrene-butadiene copolymer resins And other hydrogenated products thereof, various thermoplastic elastomers typified by polyester elastomers, various polyamides such as nylon 6, 66, 12, nylon 12, etc. From the viewpoint of further imparting oxygen absorption performance, polybutadiene And carbon-carbon unsaturated double bond-containing resins such as modified polybutadiene.

3. Arbitrary Layer In addition to the layers (A) and (B), the multilayer sheet of the present invention may contain an optional layer depending on the desired performance and the like. Examples of such an arbitrary layer include an adhesive layer, a metal foil, and a metal vapor deposition layer.

3-1. Adhesive layer In the multilayer sheet of the present invention, when a practical interlayer adhesive strength cannot be obtained between two adjacent layers, an adhesive layer is preferably provided between the two layers.
The adhesive layer preferably contains a thermoplastic resin having adhesiveness. As the thermoplastic resin having adhesiveness, for example, an acid modification in which a polyolefin resin such as polyethylene or polypropylene is modified with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, etc. Examples include polyolefin resins. As the adhesive layer, it is preferable to use a modified resin of the same type as the resin (B) used as the layer (B) from the viewpoint of adhesiveness.
The thickness of the adhesive layer is preferably 2 to 100 μm, more preferably 5 to 90 μm, and still more preferably 10 to 80 μm, from the viewpoint of ensuring molding processability while exhibiting practical adhesive strength.

3-2. Metal foil and metal vapor deposition layer The multilayer sheet of this invention may contain the metal foil and the metal vapor deposition layer from a gas-barrier property and a light-shielding viewpoint.
As the metal foil, an aluminum foil is preferable. The thickness of the metal foil is preferably 3 to 50 μm, more preferably 3 to 30 μm, still more preferably 5 to 15 μm, from the viewpoints of gas barrier properties, light shielding properties, bending resistance, and the like.
As the metal deposition layer, a resin film or the like on which a metal such as aluminum or alumina or a metal oxide film is deposited can be used. The formation method of a vapor deposition film is not specifically limited, For example, physical vapor deposition methods, such as a vacuum evaporation method, sputtering method, and an ion plating method, Chemical vapor deposition methods, such as PECVD, etc. are mentioned. The thickness of the deposited film is preferably 5 to 500 nm, more preferably 5 to 200 nm, from the viewpoints of gas barrier properties, light shielding properties, bending resistance, and the like.

3-3. Recycle layer A layer made of recycled resin can be added between the inner layer or the outer layer and the intermediate layer from the viewpoint of recyclability. It is important from the viewpoint of effective use of resources as well as reduction of manufacturing costs to grind scrap resin generated during molding and use it as a recycled resin. When using the recycled resin, it is preferable to dispose the recycled resin in the outer layer from the oxygen absorption barrier layer in terms of strength.

4). Production method of multilayer sheet The production method of the multilayer sheet of the present invention is not particularly limited, and can be produced by any method. For example, it is preferably formed by a thermoforming method, in particular, a T-die method. For example, using a multi-layer extruder composed of a plurality of extruders, feed blocks, and T dies, the materials of polyamide resin (A) and other resin (B) such as polyolefin are respectively put into a hopper and melted in the extruder. , Extruded from a T-die to a cooling roll to form a multilayer sheet.
The extruder used here may be a single-screw extruder or a multi-screw extruder. The screw used for the extrusion of the polyamide resin (A) is not particularly limited, but a rapid compression full flight screw or double flight screw is preferable.
In addition to the single manifold method using a feed block, a multi-manifold method having a plurality of manifolds inside the T die may be used.
Examples of incidental equipment for the extruder include a take-up machine equipped with a cooling roll, a sheet edge cutting device, a vent vacuum pump, and a cooling machine.

The multilayer sheet of the present invention can be further formed into a container or the like. For example, there is a method in which after heat-softening, a sheet is brought into close contact with a mold by vacuum, compressed air, or a thermoforming method using a combination of vacuum and compressed air to form a container and trimmed to obtain a container. . Here, the sheet surface temperature during thermoforming is preferably in the range of 130 to 200 ° C and more preferably in the range of 150 to 180 ° C from the viewpoint of formability. The multilayer sheet manufacturing apparatus and the container forming method are not limited to these, and any method can be applied.
In addition, this container uses a multilayer sheet made of the same type of resin as the flange part of the container as the container lid, and after filling the object to be stored by hot plate welding, high frequency welding, etc., heat sealed and sealed. Is possible. Moreover, it is preferable to use a protrusion, an easily peelable material, or the like so that the lid material is not opened at the time of heat sterilization treatment or dropping, and the lid material is easily peeled off when the container is opened.

The packaging container including the multilayer sheet of the present invention is excellent in oxygen absorption performance and oxygen barrier performance and excellent in flavor retention of contents, and thus is suitable for packaging various articles.
Preserved items include milk, dairy products, juice, coffee, tea, alcoholic beverages; liquid seasonings such as sauces, soy sauce, dressings, soups, stews, curries, infant foods, nursing foods, etc. Cooked foods; pasty foods such as jam, mayonnaise, ketchup, jelly; marine products such as tuna and fish shellfish; dairy products such as cheese and butter; processed meat products such as meat, salami, sausage and ham; carrots, Vegetables such as potatoes; Eggs; Noodles; Uncooked rice, cooked rice, cooked rice such as rice bran; powdered seasonings, powdered coffee, infant milk powder, powdered diet foods, dried vegetables, rice crackers Dry foods such as pesticides; chemicals such as agricultural chemicals and insecticides; pharmaceuticals; cosmetics; pet foods; miscellaneous goods such as shampoos, rinses and detergents; Among these, heat-sterilized treatment such as boil treatment and retort treatment, jelly using pulp, fruit juice, coffee, etc., sheep, cooked rice, processed rice products, cooked food for infants, nursing cooked food, curry, soup It is suitable for stew, jam, mayonnaise, ketchup, pet food and processed fishery products.

  In addition, before and after the filling of these objects to be stored, the packaging container including the multilayer sheet of the present invention and the objects to be stored can be sterilized in a form suitable for the objects to be stored. Sterilization methods include hot water treatment at 100 ° C. or lower, pressurized hot water treatment at 100 ° C. or higher, heat sterilization such as ultra-high temperature heat treatment at 130 ° C. or higher, electromagnetic wave sterilization of ultraviolet rays, microwaves, gamma rays, etc., ethylene oxide And gas sterilization such as hydrogen peroxide and hypochlorous acid.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
In the following examples, regarding the units constituting the copolymer,
The unit derived from metaxylylenediamine is “MXDA”,
A unit derived from 1,3-bis (aminomethyl) cyclohexane is referred to as “1,3BAC”,
The unit derived from hexamethylenediamine is “HMDA”,
The unit derived from adipic acid is “AA”,
The unit derived from isophthalic acid is “IPA”,
The unit derived from DL-alanine is “DL-Ala”,
The unit derived from DL-leucine is “DL-Leu”,
A unit derived from ε-caprolactam is referred to as “ε-CL”.
In addition, polymetaxylylene adipamide "N-MXD6",
Polypropylene "PP",
Polyethylene terephthalate is PET
Adhesive layer "AD",
The ethylene-vinyl alcohol copolymer is referred to as “EVOH”.

  The α-amino acid content, relative viscosity, terminal amino group concentration, glass transition temperature and melting point of the polyamide resin obtained in Production Example were measured by the following methods. Moreover, the film was produced from the polyamide resin obtained by the manufacture example, and the oxygen absorption amount was measured with the following method.

(1) α-amino acid content
The α-amino acid content of the polyamide resin was quantified using ¹ H-NMR (400 MHz, manufactured by JEOL Ltd., trade name: JNM-AL400, measurement mode: NON ( ¹ H)). Specifically, a 5 mass% solution of polyamide resin was prepared using formic acid-d as a solvent, and ¹ H-NMR measurement was performed.

(2) Relative viscosity 1 g of the pellet-like sample was precisely weighed and dissolved in 100 ml of 96% sulfuric acid at 20-30 ° C. with stirring. After completely dissolving, 5 ml of the solution was quickly taken into a Cannon-Fenceke viscometer and allowed to stand for 10 minutes in a constant temperature bath at 25 ° C., and then the drop time (t) was measured. Further, the dropping time (t ₀ ) of 96% sulfuric acid itself was measured in the same manner. The relative viscosity was calculated from t and t _{0 according} to the following formula.
Relative viscosity = t / t ₀

(3) Terminal amino group concentration [NH ₂ ]
The polyamide resin is precisely weighed and dissolved in a phenol / ethanol = 4/1 volume solution by stirring at 20-30 ° C. After complete dissolution, the inner wall of the container is washed with 5 ml of methanol while stirring, and 0.01 mol / L hydrochloric acid is dissolved. The terminal amino group concentration [NH ₂ ] was determined by neutralization titration with an aqueous solution.

(4) Glass transition temperature and melting point DSC measurement (differential scanning calorimetry) using a differential scanning calorimeter (manufactured by Shimadzu Corporation, trade name: DSC-60) under a nitrogen stream at a heating rate of 10 ° C / min. The glass transition temperature (Tg) and the melting point (Tm) were determined.

(5) Oxygen absorption amount Using a 30mmφ twin screw extruder (manufactured by Plastic Engineering Laboratory Co., Ltd.) equipped with a T die, the thickness of the polyamide resin was increased from the polyamide resin at a cylinder T die temperature of (polyamide resin melting point + 20 ° C). An unstretched single layer film having a thickness of about 100 μm was formed.
Two test pieces of 10 cm x 10 cm cut out from the produced unstretched single layer film were charged into a 25 cm x 18 cm three-side sealed bag made of an aluminum foil laminated film together with cotton containing 10 ml of water, and the amount of air in the bag Was sealed to 400 ml. The humidity in the bag was 100% RH (relative humidity). After storing at 40 ° C. for 7 days, after 14 days, and after 28 days, the oxygen concentration in the bag was measured with an oxygen concentration meter (trade name: LC-700F, manufactured by Toray Engineering Co., Ltd.). The amount of oxygen absorbed was calculated from the oxygen concentration.

Production Example 1 (Production of polyamide resin 1)
Weighed precisely in a pressure-resistant reaction vessel with an internal volume of 50 L equipped with a stirrer, partial condenser, full condenser, pressure regulator, thermometer, dripping tank and pump, aspirator, nitrogen inlet pipe, bottom exhaust valve, and strand die. Adipic acid (Asahi Kasei Chemicals Corporation) 13000 g (88.96 mol), DL-alanine (Musashino Chemical Laboratory Co., Ltd.) 880.56 g (9.88 mol), sodium hypophosphite 11.7 g (0. 11 mol) and 6.06 g (0.074 mol) of sodium acetate were added, and after sufficiently purging with nitrogen, the inside of the reaction vessel was sealed, and the temperature was raised to 170 ° C. with stirring while keeping the inside of the vessel at 0.4 MPa. After reaching 170 ° C., dropping of 12082.2 g (88.71 mol) of metaxylylenediamine (manufactured by Mitsubishi Gas Chemical Co., Inc.) stored in the dropping tank into the molten raw material in the reaction vessel was started, While maintaining 0.4 MPa, the temperature inside the reaction vessel was continuously raised to 240 ° C. while removing the condensed water produced outside the system. After completion of the dropwise addition of metaxylylenediamine, the inside of the reaction vessel was gradually returned to normal pressure, and then the inside of the reaction vessel was reduced to 80 kPa using an aspirator to remove condensed water. After observing the stirring torque of the stirrer during decompression, stop stirring when the specified torque is reached, pressurize the inside of the reaction tank with nitrogen, open the bottom drain valve, extract the polymer from the strand die and form a strand Cooled and pelletized with a pelletizer. Next, this pellet was charged into a stainless steel drum-type heating device and rotated at 5 rpm. The atmosphere in the reaction system was raised from room temperature to 140 ° C. under a small nitrogen flow. When the reaction system temperature reached 140 ° C., the pressure was reduced to 1 torr or less, and the system temperature was further increased to 180 ° C. in 110 minutes. From the time when the system temperature reached 180 ° C., the solid state polymerization reaction was continued at the same temperature for 180 minutes. After completion of the reaction, the decompression was terminated, the system temperature was lowered under a nitrogen stream, and the pellet was taken out when the temperature reached 60 ° C., thereby obtaining an MXDA / AA / DL-Ala copolymer (polyamide resin 1). .
In addition, the preparation composition ratio of each monomer was metaxylylenediamine: adipic acid: DL-alanine = 47.3: 47.4: 5.3 (mol%).

Production Example 2 (Production of polyamide resin 2)
MXDA / AA in the same manner as in Production Example 1 except that the charged composition ratio of each monomer was metaxylylenediamine: adipic acid: DL-alanine = 44.4: 44.5: 11.1 (mol%). / DL-Ala copolymer (polyamide resin 2) was obtained.

Production Example 3 (Production of polyamide resin 3)
MXDA / AA in the same manner as in Production Example 1 except that the charged composition ratio of each monomer was metaxylylenediamine: adipic acid: DL-alanine = 41.1: 41.3: 17.6 (mol%). / DL-Ala copolymer (polyamide resin 3) was obtained.

Production Example 4 (Production of polyamide resin 4)
MXDA / AA in the same manner as in Production Example 1 except that the composition ratio of each monomer was metaxylylenediamine: adipic acid: DL-alanine = 33.3: 33.4: 33.3 (mol%). / DL-Ala copolymer (polyamide resin 4) was obtained.

Production Example 5 (Production of polyamide resin 5)
The α-amino acid was changed to DL-leucine (manufactured by Ningbo Haishu Bio-technology), and the composition ratio of each monomer was changed to metaxylylenediamine: adipic acid: DL-leucine = 44.3: 44.6: 11.1. An MXDA / AA / DL-Leu copolymer (polyamide resin 5) was obtained in the same manner as in Production Example 1 except that the content was (mol%).

Production Example 6 (Production of polyamide resin 6)
The dicarboxylic acid component was changed to a mixture of isophthalic acid (manufactured by EI International Chemical Co., Ltd.) and adipic acid, and the composition ratio of each monomer was changed to metaxylylenediamine: adipic acid: isophthalic acid: DL- MXDA / AA / IPA / DL-Ala copolymer (polyamide resin 6) in the same manner as in Production Example 1 except that alanine = 44.3: 39.0: 5.6: 11.1 (mol%). Got.

Production Example 7 (Production of polyamide resin 7)
Ε-Caprolactam (manufactured by Ube Industries) was used as a comonomer, the amino acid was changed to DL-leucine, and the composition ratio of each monomer was changed to metaxylylenediamine: adipic acid: DL-leucine: ε-caprolactam = MXDA / AA / DL-Leu / ε-CL copolymer (polyamide resin 7) in the same manner as in Production Example 1 except that 41.0: 41.3: 11.8: 5.9 (mol%) was used. Got.

Production Example 8 (Production of polyamide resin 8)
The diamine component was changed to a mixture of 1,3-bis (aminomethyl) cyclohexane (Mitsubishi Gas Chemical Co., Ltd.) and metaxylylenediamine, and the charge composition ratio of each monomer was changed to metaxylylenediamine: 1,3- MXDA / 1,3BAC in the same manner as in Production Example 1 except that bis (aminomethyl) cyclohexane: adipic acid: DL-alanine = 33.2: 11.1: 44.6: 11.1 (mol%) / AA / DL-Ala copolymer (polyamide resin 8) was obtained.

Production Example 9 (Production of polyamide resin 9)
The diamine component was changed to a mixture of hexamethylenediamine (manufactured by Showa Chemical Co., Ltd.) and metaxylylenediamine, and the composition ratio of each monomer was changed to metaxylylenediamine: hexamethylenediamine: adipic acid: DL-alanine = 33. .3: 11.1: 44.5: 11.1 (mol%) Except that it was set as the same as manufacture example 1, the MXDA / HMDA / AA / DL-Ala copolymer (polyamide resin 9) was obtained. .

Production Example 10 (Production of polyamide resin 10)
The dicarboxylic acid component was changed to a mixture of isophthalic acid (manufactured by EI International Chemical Co., Ltd.) and adipic acid, DL-alanine was not added, and the composition ratio of each monomer was changed to metaxylylenediamine: An MXDA / AA / IPA copolymer (polyamide resin 10) was obtained in the same manner as in Production Example 1, except that adipic acid: isophthalic acid = 50.0: 44.0: 6.0 (mol%).

Production Example 11 (Production of polyamide resin 11)
N-MXD6 was prepared in the same manner as in Production Example 1 except that DL-alanine was not added and the charged composition ratio of each monomer was metaxylylenediamine: adipic acid = 49.9: 50.1 (mol%). (Polyamide resin 11) was obtained.

  Table 1 shows the charged monomer composition of polyamide resins 1 to 11 and the measurement results of the α-amino acid content, relative viscosity, terminal amino group concentration, glass transition temperature, melting point, and oxygen absorption amount of the obtained polyamide resin.

  Next, in Examples 1 to 20 and Comparative Examples 1 to 13, a multilayer sheet was prepared using the polyamide resins 1 to 10, and a multilayer container was manufactured using the multilayer sheet.

Example 1
Using a multi-layer extruder equipped with three extruders, a feed block, and a T die, polyamide resin 1 was fed from the first extruder at 250 ° C., and polypropylene from the second extruder (manufactured by Nippon Polypro Co., Ltd.). , Trade name: Novatec, grade: FY6) at 230 ° C., adhesive resin (Mitsui Chemicals, trade name: Admer, grade: QB515) from the third extruder at 220 ° C., 30 It extruded and wound up on the cooling roll at 0 degreeC. The multilayer sheet obtained here has a three-kind five-layer structure in the order of outer layer, polypropylene layer / adhesive resin layer / polyamide resin 1 layer / adhesive resin layer / polypropylene layer. Each layer had a thickness of 300/10/60/10/300 (μm).
Next, using a compressed air vacuum forming machine (made by Asano Laboratory Co., Ltd.) equipped with plug assist, thermoforming was performed when the sheet surface temperature reached 170 ° C., and the opening was 79 mm square × bottom 63 mm × depth. A multilayer container having a thickness of 25 mm, a surface area of 110 cm ² , and a volume of 100 ml was produced.

Examples 2-9
As shown in Table 2, a multilayer sheet and a multilayer container were produced in the same manner as in Example 1 except that polyamide resins 2 to 9 were used instead of the polyamide resin 1 for the polyamide resin layer.

Examples 10-20
A multilayer sheet and a multilayer container were produced in the same manner as in Example 1 except that the polyamide resin and the layer configuration described in Table 2 were used.
In Examples 18 to 20, Toyobo Co., Ltd., trade name: IP560 was used as PET, and Mitsubishi Chemical Corporation, trade names: MODIC-AP, F534A were used as adhesive resins.

Comparative Examples 1-12
As shown in Table 2, a polyamide sheet and a multilayer container were prepared in the same manner as in Example 1 except that a polyamide resin 10 was used instead of the polyamide resin 1 in the polyamide resin layer, and the layer structure shown in Table 2 was adopted. Produced.
In Comparative Examples 2, 5, 8, and 11, cobalt (II) stearate was added to the polyamide resin 10 so that the cobalt content was 400 ppm.
In Comparative Examples 3, 6, 9, and 12, cobalt stearate (II) was added to the polyamide resin 10 so that the cobalt content was 100 ppm, and maleic acid-modified polybutadiene (Nippon Petrochemical Co., Ltd.) was added. 3 parts by mass of 100% by mass of polyamide resin 10 was added to the product, product name: M-2000-20.
In Comparative Examples 10 to 12, Toyobo Co., Ltd., trade name: IP560 was used as PET, and Mitsubishi Chemical Corporation, trade names: MODIC-AP and F534A were used as adhesive resins.

Comparative Example 13
As shown in Table 2, an attempt was made to produce a multilayer sheet and a multilayer container in the same manner as in Example 1 except that the polyamide resin 11 was used instead of the polyamide resin 1 in the polyamide resin layer. Due to the high crystallization speed, thermoforming could not be performed.

About the multilayer container produced in Examples 1-20 and Comparative Examples 1-12, the oxygen permeability, the L-ascorbic acid residual rate, and the odor and taste after opening were evaluated as follows.
(1) Oxygen permeability The oxygen permeability of the multi-layer container was determined according to ASTM D3985 using an oxygen permeability measuring device (manufactured by MOCON, model: OX-TRAN 2/61). In Examples 1 to 17 and Comparative Examples 1 to 9, boil treatment was performed at 90 ° C. for 30 minutes using an autoclave (SR-240, trade name, manufactured by Tommy Seiko Co., Ltd.). On the other hand, in Examples 18 to 20 and Comparative Examples 10 to 12, once 80 ml of 90 ° C. hot water was injected and left at room temperature for 10 minutes, the entire amount of water was discarded. Then, 20 ml of distilled water was filled from the opening of the multilayer container, and the opening was sealed by heat welding with an aluminum foil laminated film. Two holes were made in the aluminum foil laminated film, a copper tube was inserted, and after hardening with an epoxy resin, it was connected to an oxygen permeability measuring device and measured for one month in an atmosphere of 23 ° C. and 60% relative humidity. .

(2) L-ascorbic acid residual ratio 80 ml of 10% aqueous solution of L-ascorbic acid was filled from the opening of the multilayer container, and the opening was sealed by heat welding with an aluminum foil laminated film. In Examples 1-17 and Comparative Examples 1-9, after performing a retort process for 121 minutes 30 minutes using an autoclave (SR-240, brand name, Tomy Seiko Co., Ltd.), this container is 23 degreeC, It was stored for 1 month in an environment of 50% RH. In Examples 18 to 20 and Comparative Examples 10 to 12, after storing for 3 months in an environment of 23 ° C. and 50% RH without heat treatment, the content solution was taken out and 10 ml of the content solution was put into a 100 ml capacity tall beaker. Then, 5 ml of a mixed aqueous solution of metaphosphoric acid and acetic acid and 40 ml of distilled water were added. Subsequently, 0.05 mol / l iodine solution was used as a titrant, and titration was performed by an inflection point detection method using a potentiometric titration apparatus. The L-ascorbic acid residual rate was determined from the result. In addition, if the residual rate of L-ascorbic acid is high, it means that it is excellent in the effect which suppresses the oxidative degradation of the content.

(3) Odor and taste at the time of opening The obtained multilayer container was fully filled with mineral water and thermally welded with an aluminum foil laminated film, and then stored in a thermostatic bath at 40 ° C. and 50% RH for 1 month. After storage, five panelists sniffed the scent in the container immediately after opening and evaluated the presence or absence of off-flavors.
In addition, after opening, five panelists included mineral water in their mouths and evaluated the presence or absence of changes in the taste of mineral water.
○: There is no off-flavor and there is no change in the taste of mineral water.
X: There is even a slight odor or there is even a slight change in the taste of mineral water.
Table 2 shows the evaluation results.

  The multilayer containers of Examples 1 to 20 were all excellent in oxygen permeability and L-ascorbic acid residual ratio as compared with the multilayer containers having the same layer configuration in Comparative Examples 1, 4, 7, and 10. In Comparative Examples 2, 5, 8, and 11 using cobalt (II) stearate to provide oxygen absorption performance, delamination occurred after boiling or after filling with hot water, and the barrier properties deteriorated. I could not. In Comparative Examples 3, 6, 9, and 12 in which cobalt stearate (II) and maleic acid-modified polybutadiene were added to the polyamide resin layer, although the oxygen permeability was good, the odor and taste at the time of opening were inferior. .

  The multilayer sheet of the present invention can be suitably used as a packaging material.

Claims (7)

A multilayer sheet comprising a layer (A) containing a polyamide resin (A) and a layer (B) containing the resin (B) as a main component,
The polyamide resin (A) is
An aromatic diamine unit represented by the following general formula (I-1), an alicyclic diamine unit represented by the following general formula (I-2), and a straight chain represented by the following general formula (I-3) 25 to 50 mol% of diamine units containing at least 50 mol% in total of at least one diamine unit selected from the group consisting of aliphatic diamine units;
A dicarboxylic acid unit containing a total of 50 mol% or more of a linear aliphatic dicarboxylic acid unit represented by the following general formula (II-1) and / or an aromatic dicarboxylic acid unit represented by the following general formula (II-2) 25 to 50 mol%,
A multilayer sheet comprising 0.1 to 50 mol% of a structural unit represented by the following general formula (III) , wherein the diamine unit contains 50 mol% or more of a metaxylylenediamine unit .

[In the general formula (I-3), m represents an integer of 2 to 18. In the general formula (II-1), n represents an integer of 2 to 18. In the general formula (II-2), Ar represents an arylene group. In the general formula (III), R represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. ]   The multilayer sheet according to claim 1, wherein R in the general formula (III) is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms. The linear aliphatic dicarboxylic acid unit comprises adipic acid unit, sebacic acid unit and 1,12 at least one selected from the group consisting of dodecane dicarboxylic acid unit in a total of 50 mole% or more, according to claim 1 or 2 A multilayer sheet as described in 1. The aromatic dicarboxylic acid unit, isophthalic acid unit, including terephthalic acid units, and at least one selected from the group consisting of 2,6-naphthalene dicarboxylic acid unit in a total of 50 mole% or more, more of claims 1 to 3 A multilayer sheet according to any one of the above. The polyamide resin (A) further contains an ω-aminocarboxylic acid unit represented by the following general formula (X) in an amount of 0.1 to 49.9 mol% in all structural units of the polyamide resin (A). Item 5. The multilayer sheet according to any one of Items 1 to 4 .

[In said general formula (X), p represents the integer of 2-18. ] The multilayer sheet according to claim 5 , wherein the ω-aminocarboxylic acid unit contains 50 mol% or more of a total of 6-aminohexanoic acid units and / or 12-aminododecanoic acid units. The multilayer sheet according to any one of claims 1 to 6 , wherein the polyamide resin (A) has a relative viscosity of 1.8 or more and 4.2 or less.