JP2019059905A - Resin composition and multilayer structure using the same - Google Patents

Abstract

To provide a resin composition that can form a multilayer structure where occurrence of a poor appearance is suppressed even when multilayer co-extrusion molding is performed, and deterioration of transparency during melting molding is improved.SOLUTION: A resin composition contains an ethylene-vinyl alcoholic copolymer (A) and a C2-17 monovalent carboxylic acid metal salt with a hydroxy group (B). The content of the metal salt (B) is 0.01-5 parts relative to the ethylene-vinyl alcoholic copolymer (A) 100 parts.SELECTED DRAWING: None

Description

  The present invention relates to a resin composition using an ethylene-vinyl alcohol copolymer (hereinafter sometimes abbreviated as "EVOH") and a multilayer structure using the same, and more specifically, A resin composition capable of forming a multilayer structure in which the occurrence of appearance defects is suppressed and a deterioration in color tone at the time of melt molding is improved even when multilayer coextrusion molding is applied, and a resin composition using the same The present invention relates to a multilayer structure including an object layer.

  Packaging materials for packaging food and various articles often require gas barrier properties such as oxygen. This is to prevent the oxidative deterioration of the contents of the package due to oxygen or the like, and to maintain the freshness of the food for a long time. For this reason, in the conventional packaging material, the gas barrier layer which prevents permeation | transmission of oxygen etc. was provided, and permeation | transmission of oxygen etc. was prevented.

  Examples of the gas barrier layer include a gas barrier layer generally made of an inorganic substance and a gas barrier layer made of an organic substance. As the gas barrier layer made of an inorganic substance, a metal layer such as an aluminum foil or an aluminum deposited layer, or a metal compound layer such as a silicon oxide deposited layer or an aluminum oxide deposited layer is used. However, metal layers such as aluminum foil and aluminum vapor deposition have disadvantages such as the inability to see the contents of the package and poor discardability.

  On the other hand, as a gas barrier layer made of an organic substance, a layer made of a polyvinylidene chloride polymer and a layer made of a vinyl alcohol polymer such as polyvinyl alcohol or EVOH are used. In recent years, the amount of polyvinylidene chloride-based polymer used has been greatly reduced due to the possibility of generation of harmful chlorine compounds upon incineration and disposal. Layers made of vinyl alcohol polymers are transparent and have the advantage of less problems in terms of disposal, and thus are widely used for packaging materials.

  For example, a multilayer structure in which a thermoplastic resin other than EVOH is laminated via the adhesive resin layer or the polyamide resin layer as an intermediate layer as the packaging material is exemplified. As described above, such a multilayer structure takes advantage of its excellent gas barrier properties and transparency to form a film or sheet as a packaging material for food packaging materials, pharmaceutical packaging materials, industrial chemical packaging materials, agrochemical packaging materials, etc. Or molded into a container such as a bottle and used.

  In forming such a multilayer structure, melt molding is generally applied from the viewpoint of productivity. However, since EVOH contains a large amount of hydroxy groups, it is susceptible to thermal degradation, and it is known to blend components for the purpose of improving melt formability.

  Generally, for the purpose of improving the moldability of EVOH, for example, Patent Document 1 discloses a saponified ethylene-vinyl acetate copolymer (A) having an ethylene content of 20 to 60 mol% and a saponification degree of 90 mol% or more. A metal having a specific chemical formula obtained by heating one or two or more kinds of aliphatic monocarboxylic acids having 12 to 30 carbon atoms and an oxide or hydroxide of a periodic table group 2 metal by a dry direct method It is described that the resin composition comprising the soap (B) is excellent in heat stability and processability (long run formability, retention property, purge property) (Patent Document 1).

  In recent years, a sense of security in particular of contents is strongly demanded, so that a multilayer structure with high visibility (transparency) tends to be preferred so that the contents can be confirmed from the outside. On the other hand, Patent Document 2 discloses that on at least one surface of a layer containing a saponified ethylene-vinyl ester copolymer, through an adhesive resin layer, a saponified other than ethylene-vinyl ester copolymer. A multilayer structure in which a thermoplastic resin layer is laminated, wherein the thickness (X) of the interface layer at the laminated interface of the layer containing the ethylene-vinyl ester copolymer saponified product and the adhesive resin layer is The EVOH layer / adhesive resin layer is controlled by controlling the resin flowability at the interface of the EVOH layer / adhesive resin layer by using a multilayer structure characterized by having 50 to 400 nm per one surface of the interface. An appearance defect due to interface roughening generated at the laminated interface of the present invention is reduced, and in particular, a technique is obtained which can obtain a multilayer structure with less decrease in image definition.

JP 2000-290455 A International Publication No. 2016/148271

  However, with the recent advancement of molding technology (for example, diversification of feed block / die shapes, high functionality of molding apparatus, etc.) and high functionality of multilayer structure (for example, increase in the number of layers, etc.) When extruding, further improvement is desired for the appearance of the resulting multilayer structure, particularly the transparency of the multilayer structure.

  Under such circumstances, the present invention uses a resin composition capable of forming a multilayer structure in which the occurrence of appearance defects is suppressed and the deterioration of transparency at the time of melt molding is improved. It is an object of the present invention to provide a multilayer structure including a resin composition layer.

  However, as a result of intensive studies conducted by the present inventor in view of the above circumstances, a resin composition containing EVOH (A) containing a monovalent carboxylic acid metal salt (B) having a hydroxy group and a specific number of carbon atoms in EVOH (A) The present invention was completed by using a product.

  That is, this invention makes 1st summary the resin composition containing EVOH (A), and a C2-C17 monovalent carboxylic acid metal salt (B) which has a hydroxyl group and has a hydroxyl group.

  And this invention is the 2nd summary of the multilayer structure by which thermoplastic resin layers other than the said resin composition are laminated | stacked via the adhesive resin layer on the at least one surface of the layer which consists of said resin composition. A third aspect of the present invention is a multilayer structure in which a polyamide resin layer is laminated on at least one surface of a resin composition layer made of the above resin composition.

  The present invention is a resin composition characterized in that EVOH (A) contains a monovalent carboxylic acid metal salt (B) having a hydroxy group and having 2 to 17 carbon atoms. For this reason, in the multilayer structure obtained by using the above-mentioned resin composition, for example, appearance defects caused by interface roughening occurring at the laminated interface of EVOH layer / adhesive resin layer and / or EVOH layer / polyamide resin layer are suppressed. And, it is an excellent multilayer structure with highly improved transparency during melt molding.

  Hereinafter, although the configuration of the present invention will be described in detail, these show one example of the preferred embodiments, and are not specified in the contents.

  The present invention provides EVOH (A), and a monovalent carboxylic acid metal salt (B) having a hydroxy group and having 2 to 17 carbon atoms (hereinafter, such a component may be referred to as a metal salt (B)) It is a resin composition characterized by containing.

<EVOH (A)>
The EVOH (A) used in the present invention will be described.
The EVOH (A) used in the present invention is usually a resin obtained by copolymerizing ethylene and a vinyl ester type monomer and then saponifying, and is a water-insoluble thermoplastic resin. As the polymerization method, any known polymerization method may be used, for example, solution polymerization, suspension polymerization and emulsion polymerization, but generally, solution polymerization using methanol as a solvent is used. Saponification of the resulting ethylene-vinyl ester copolymer can also be carried out by known methods.
That is, the EVOH (A) used in the present invention is mainly composed of an ethylene structural unit and a vinyl alcohol structural unit, and in some cases, contains a slight amount of a vinyl ester structural unit remaining without being saponified.

  As the above-mentioned vinyl ester-based monomer, vinyl acetate is typically used from the viewpoint of easy availability from the market and good treatment efficiency of impurities at the time of production. Besides, for example, aliphatic vinyl esters such as vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl stearate, and the like, benzoic acid Examples thereof include aromatic vinyl esters such as vinyl acid and the like, and are usually aliphatic vinyl esters having 3 to 20 carbon atoms, preferably 4 to 10 carbon atoms, and particularly preferably 4 to 7 carbon atoms. These are usually used alone, but two or more species may be used simultaneously as required.

  The content of the ethylene structural unit in EVOH (A) is a value measured based on ISO 14663, and is usually 20 to 60 mol%, preferably 25 to 50 mol%, particularly preferably 25 to 40 mol%. If the content is too small, the gas barrier properties at high humidity and the melt moldability tend to decrease, and if too large, the gas barrier properties tend to decrease.

  The saponification degree of the vinyl ester component in EVOH (A) is a value measured based on JIS K 6726 (wherein EVOH is a solution uniformly dissolved in water / methanol solvent), and usually 90 to 100 mol%, It is preferably 95 to 100 mol%, particularly preferably 99 to 100 mol%. If the degree of saponification is too low, the gas barrier properties, thermal stability, moisture resistance and the like tend to decrease.

  The melt flow rate (MFR) (210 ° C., load 2160 g) of the above EVOH (A) is usually 0.5 to 100 g / 10 min, preferably 1 to 50 g / 10 min, particularly preferably 3 to 35 g It is 10 minutes. When the MFR is too high, the film forming property tends to be lowered. If the MFR is too low, melt extrusion tends to be difficult.

Moreover, the structural unit derived from the comonomer shown below may be further included in EVOH (A) used for this invention in the range (for example, 10 mol% or less) which does not inhibit the effect of this invention.
Examples of the comonomer include olefins such as propylene, 1-butene and isobutene, 2-propen-1-ol, 3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol Hydroxy-containing olefins such as 3,4-dihydroxy-1-butene, 5-hexene-1,2-diol, 2-methylenepropane-1,3-diol, etc., and esterification products thereof; Diacetoxy-1-butene, 2,3-diacetoxy-1-allyloxypropane, 2-acetoxy-1-allyloxy-3-hydroxypropane, 3-acetoxy-1-allyloxy-2-hydroxypropane; 1,3-diacetoxy- 2-Methylenepropane, 1,3-Dipropionyloxy-2-methylenepropane, 1,3-Dibutyronyloxy Hydroxymethylvinylidene diacetates such as 2-methylenepropane, glycerol monoallyl ether, glycerol monovinyl ether, glycerol monounsaturated alkyl ethers such as glycerol monoisopropenyl ether, acrylic acid, methacrylic acid, crotonic acid, (anhydride) phthalate Acid, unsaturated acid such as (anhydride) maleic acid, (anhydride) itaconic acid or a salt thereof or mono- or dialkyl ester having 1 to 18 carbon atoms, acrylamide, N-alkyl acrylamide having 1 to 18 carbon atoms, N, N -Acrylamides such as dimethyl acrylamide, 2-acrylamidopropane sulfonic acid or salts thereof, acrylamidopropyldimethylamine or acid salts thereof or quaternary salts thereof, methacrylamides, N-aryls having 1 to 18 carbon atoms Methacrylamides such as N-methacrylamido, N, N-dimethylmethacrylamide, 2-methacrylamidopropanesulfonic acid or a salt thereof, methacrylamidopropyldimethylamine or an acid salt thereof or a quaternary salt thereof, N-vinylpyrrolidone, N- N-vinylamides such as vinylformamide and N-vinylacetamide, vinyl cyanides such as acrylonitrile and methacrylonitrile, alkyl vinyl ethers having 1 to 18 carbon atoms, vinyl ethers such as hydroxyalkyl vinyl ethers and alkoxyalkyl vinyl ethers, vinyl chloride, Halogenated vinyl compounds such as vinylidene chloride, vinyl fluoride, vinylidene fluoride, vinyl bromide, vinylsilanes such as trimethoxyvinylsilane, halogenated anions such as allyl acetate and allyl chloride And comonomers such as allyl alcohol, allyl alcohol, allyl alcohol such as dimethoxyallyl alcohol, trimethyl- (3-acrylamido-3-dimethylpropyl) -ammonium chloride, acrylamido-2-methylpropane sulfonic acid and the like.

  Furthermore, "post-modified" EVOHs such as urethanization, acetalization, cyanoethylation, oxyalkylenation and the like can also be used.

  In particular, EVOH having a primary hydroxy group in the side chain is preferable in that the secondary formability becomes good while maintaining the gas barrier properties, and in particular, EVOH in which a hydroxy group-containing α-olefin is copolymerized is preferable, In particular, EVOH having a 1,2-diol in the side chain is preferable.

  The EVOH having a 1,2-diol in the side chain is a compound containing a 1,2-diol structural unit in the side chain. Specifically, the 1,2-diol structural unit is a structural unit represented by the following general formula (1).

〔上記一般式（１）において、Ｒ¹，Ｒ²およびＲ³は、それぞれ独立して水素原子または有機基を示し、Ｘは単結合または結合鎖を示す。Ｒ⁴，Ｒ⁵およびＲ⁶は、それぞれ独立して水素原子または有機基を示す。〕

[In the above general formula (1), R ¹ , R ² and R ³ each independently represent a hydrogen atom or an organic group, and X represents a single bond or a bond chain. R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or an organic group. ]

  The organic group in the 1,2-diol structural unit represented by the above general formula (1) is, for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group Examples thereof include saturated hydrocarbon groups such as groups, aromatic hydrocarbon groups such as phenyl and benzyl groups, halogen atoms, hydroxy groups, acyloxy groups, alkoxycarbonyl groups, carboxyl groups and sulfonic acid groups.

  In particular, when it contains a 1,2-diol structural unit represented by the above general formula (1), its content is usually 0.1 to 20 mol%, further 0.1 to 15 mol%, especially 0. It is preferably 1 to 10 mol%.

  In addition, EVOH (A) used in the present invention may be a mixture with another different EVOH, and as the above other EVOH, one having a different content of ethylene structural unit, a compound represented by the general formula (1) Those having different contents of 1,2-diol structural units, those having different saponification degrees, those having different melt flow rates (MFR), and those having other copolymerization components different can be mentioned.

<Monovalent metal carboxylate having a hydroxy group (B)>
In the present invention, a monovalent carboxylic acid metal salt (B) having a hydroxy group and having 2 to 17 carbon atoms is used. The anion which comprises the said metal salt (B) is a monovalent | monohydric carboxylic acid, ie, the anion derived from one carboxyl group, and has a hydroxyl group, and it is C2-C17. By using a monovalent carboxylic acid metal salt having a hydroxy group and a medium carbon number as the metal salt (B), the affinity between EVOH (A) and the metal salt (B) is increased, For example, an excellent multilayer in which appearance defects due to interface roughening generated at the laminated interface of EVOH layer / adhesive resin layer and / or EVOH layer / polyamide resin layer are suppressed and transparency at the time of melt molding is greatly improved It is presumed that a structure can be obtained.

  Examples of such metal salts (B) include metal salts of monovalent aliphatic carboxylic acids having a hydroxy group such as glycolic acid, gluconic acid, lactic acid, glyceric acid, hydroxybutyric acid, hydroxylauric acid; salicylic acid, silicic acid, protocatechuic acid, There are metal salts of monovalent aromatic carboxylic acids having a hydroxy group such as gentisic acid, gallic acid, mandelic acid, benzylic acid, phloretic acid and the like, and from the viewpoint of productivity, preferably monovalent aliphatic carboxylic acids having a hydroxy group It is a metal salt, more preferably a metal gluconate.

The carbon number of the metal salt (B) is preferably 2 to 15, particularly preferably 3 to 10. When the value is within the above range, the effects of the present invention tend to be obtained more significantly.
The valence number of the hydroxy group that the metal salt (B) has is usually 1 to 3 and is preferably monovalent in terms of productivity.

 Moreover, as a metal species of metal salt (B), for example, monovalent metals: alkali metals such as sodium and potassium; polyvalent metals: alkaline earth metals such as magnesium, calcium and barium; periodic table such as zinc The metal etc. which are chosen from 10-12 groups can be mentioned. A polyvalent metal is preferred in that the effects of the present invention can be more remarkably obtained. More preferably, it is a metal selected from alkaline earth metals such as magnesium, calcium, barium and the like from periodic table group 10 to 12 such as zinc, and still more preferably selected from periodic group 10 to 12 group such as zinc It is a metal that The metal selected from the periodic table groups 10 to 12 is more preferably a metal selected from the periodic table d block fourth period, and specifically, nickel, copper, zinc.

 That is, the metal salt (B) is preferably a monovalent aliphatic carboxylic acid having a hydroxy group or a polyvalent metal salt of a monovalent aromatic carboxylic acid having a hydroxy group, more preferably a monovalent fatty acid having a hydroxy group Group metal salt of a group carboxylic acid, more preferably a polyvalent metal salt of gluconic acid, still more preferably an alkaline earth metal salt of gluconic acid and a metal salt selected from Groups 10 to 12 of the periodic table And most preferably zinc gluconate.

 The metal salt (B) may be an anhydride or a hydrate, and in view of economy and availability, the hydrate is preferable, and the saturated hydrate is most preferable. .

  The content of the metal salt (B) is preferably 0.01 to 5 parts, preferably 0.03 to 3 parts, and more preferably 0.05 to 1 part based on 100 parts of EVOH (A). Part, more preferably 0.09 to 1 part. If the content is too small, the effect of improving transparency at the time of melt molding tends to decrease, and if too large, the thermal stability and color tone stability tend to decrease.

<Other Thermoplastic Resin (C)>
The resin composition of the present invention may contain, as a resin component, a thermoplastic resin other than EVOH (A) in a range of usually 30% by weight or less with respect to EVOH (A). Hereinafter, thermoplastic resins other than this EVOH (A) are called "other thermoplastic resin (C)."

  Examples of the other thermoplastic resin (C) include linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-propylene copolymer, Ethylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, ethylene-acrylic acid ester copolymer, polypropylene, propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer , Polyolefins, homopolymers or copolymers of olefins such as polypentene, Polycyclic olefins, or polyolefin resins such as those obtained by graft-modifying homopolymers or copolymers of these olefins with unsaturated carboxylic acids or esters thereof, polystyrene Resin, polyester, polyamide, copolyamide , Polyvinyl chloride, polyvinylidene chloride, acrylic resin, vinyl ester resin, polyester elastomers, polyurethane elastomers, chlorinated polyethylene, thermoplastic resins such as chlorinated polypropylene and the like.

  In particular, when a multilayer structure comprising the resin composition of the present invention is produced and used as a packaging material for food, the EVOH layer is eluted at the end of the packaging material after hot water sterilization treatment of the packaging material. It is preferable to mix | blend polyamide-type resin as another thermoplastic resin (C) in order to prevent that. In the polyamide resin, an amide bond can form a network structure by interaction with the OH group and / or ester group of EVOH, which can prevent the elution of EVOH at the time of hydrothermal treatment . Therefore, in the case of using the resin composition of the present invention as a packaging material for retort food or boiled food, it is preferable to blend a polyamide resin.

A well-known thing can be used as said polyamide-type resin.
Specifically, for example, polycapramide (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-ω-aminononanoic acid (nylon 9), porundecane amide (nylon 11), polylauryl lactam (nylon 12) And homopolymers. In addition, as a copolymerized polyamide resin, polyethylenediamine adipamide (nylon 26), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebacamide (nylon) 610), polyhexamethylene dodecamide (nylon 612), polyoctamethylene adipamide (nylon 86), polydecamethylene adipamide (nylon 108), caprolactam / lauryl lactam copolymer (nylon 6/12), caprolactam / Ω-aminononanoic acid copolymer (nylon 6/9), caprolactam / hexamethylene diammonium adipate copolymer (nylon 6/66), lauryl lactam / hexamethylene diammonium adipate copolymer (nylon 12/66), Echi Diaminediamine adipamide / hexamethylenediammonium adipate copolymer (nylon 26/66), caprolactam / hexamethylenediammonium adipate / hexamethylenediammonium sebacate copolymer (nylon 66/610), ethylene ammonium adipate / hexamate Aliphatic polyamides such as methylenediammonium adipate / hexamethylenediammonium sebacate copolymer (nylon 6/66/610), polyhexamethylene isophthalamide, polyhexamethylene terephthalamide, polymethaxylylene adipamide, hexamethylene Aromatic polymers such as isophthalamide / terephthalamide copolymer, poly-P-phenylene terephthalamide, and poly-P-phenylene · 3-4 ′ diphenyl ether terephthalamide Amide, amorphous polyamide, these polyamide resins methylene benzylamine, meta those modified with an aromatic amine xylene diamine and xylylene adipate and the like. Alternatively, these terminal-modified polyamide resins may be used, and preferably terminal-modified polyamide resins.

Specifically, the terminal-modified polyamide resin is, for example, a terminal-modified polyamide resin modified with a hydrocarbon group having 1 to 22 carbon atoms, and commercially available resins may be used. More specifically, for example, the number [X] of the terminal COOH group of the terminal modified polyamide resin and the terminal CONR ¹ R ² group (wherein R ¹ is a hydrocarbon group having 1 to 22 carbon atoms, R ² is a hydrogen atom or The number [Y] of hydrocarbon groups having 1 to 22 carbon atoms is
100 × Y / (X + Y) ≧ 5
An end-modified polyamide-based resin that satisfies the above requirements is preferably used.

  The terminal-modified polyamide resin is a carboxyl group of an ordinary non-modified polyamide resin modified with N-substituted amide using a terminal regulator, relative to the total number of carboxyl groups contained in the polyamide resin before modification. Polyamide resin modified by at least 5%. If the amount of modification is too small, a large amount of carboxyl groups in the polyamide resin will be present, and such carboxyl groups react with EVOH during melt molding to generate gel and the like, and the appearance of the obtained film tends to be poor. Tend. The terminal-modified polyamide resin can be produced, for example, by the method described in Japanese Patent Publication No. 8-19302.

  When using a polyamide-based resin as another thermoplastic resin (C), the content ratio of EVOH / polyamide-based resin is usually 99/1 to 70/30 by weight ratio, and preferably 97/3 to 75/25. , Particularly preferably 95/5 to 85/15. When the weight ratio of the polyamide resin is too large, the long run formability and the gas barrier property tend to be lowered. When the weight ratio of the polyamide-based resin is too small, the elution suppression effect of EVOH after the hot water treatment tends to be reduced.

<Inorganic filler (D)>
In the resin composition of the present invention, for the purpose of improving the gas barrier properties, EVOH (A) (optionally, other thermoplastic resin (C)), metal salt (B), and further inorganic filler (D) May be contained.

  The inorganic filler (D) is preferably a plate-like inorganic filler from the viewpoint of exhibiting more gas barrier properties, for example, kaolin containing hydra-containing aluminum silicate as a main component and having a plate-like particle structure Examples include silicates such as mica and smectite, and complex salts such as talc comprising magnesium hydroxide and silicate. Among these, kaolin is preferably used. The type of kaolin is not particularly limited, and may or may not be calcined. Preferred is calcined kaolin.

  The gas barrier properties of the resin composition are further improved by blending the inorganic filler (D). In particular, in the case of a plate-like inorganic filler, since it has a multilayer structure, in the case of film formation, the plate-like surface of the plate-like inorganic filler tends to be oriented in the plane direction of the film. Thus, it is speculated that the plate-like inorganic filler oriented in the plane direction particularly contributes to the oxygen blocking of the resin composition layer (for example, the film).

  The content of the inorganic filler (D) is usually 1 to 20% by weight, preferably 3 to 18% by weight, more preferably 5 to 15% by weight, based on EVOH (A). When the content is too small, the gas barrier property improving effect tends to be lowered, and when the content is too large, the transparency tends to be lowered.

<Oxygen absorbent (E)>
The resin composition of the present invention further contains an oxygen absorbent (E) in addition to EVOH (A) and metal salt (B) for the purpose of improving the gas barrier properties after hot water sterilization treatment (retort treatment). May be

  The oxygen absorbent (E) is a compound that scavenges oxygen more quickly than the contents to be packaged. Specific examples thereof include inorganic oxygen absorbents, organic oxygen absorbents, and composite oxygen absorbents which use an inorganic catalyst (transition metal catalyst) in combination with an organic compound.

  Examples of the inorganic oxygen absorbent include metals and metal compounds, which react with oxygen to absorb oxygen. The metal is preferably a metal having a larger ionization tendency than hydrogen (Fe, Zn, Mg, Al, K, Ca, Ni, Sn, etc.), typically iron. These metals are preferably used in powder form. As the iron powder, any of known iron powders, such as reduced iron powder, atomized iron powder, electrolytic iron powder, etc., can be used without particular limitation, regardless of the production method thereof. Moreover, iron used may be one obtained by reducing iron which has been oxidized once. Moreover, as said metal compound, an oxygen deficient metal compound is preferable. Here, examples of the oxygen deficient metal compound include cerium oxide (CeO 2), titanium oxide (TiO 2), zinc oxide (ZnO), etc. These oxides are extracted from the crystal lattice by reduction treatment. As a result, oxygen deficiency occurs, and by reacting with oxygen in the atmosphere, the oxygen absorbing ability is exhibited. It is also preferable that such metals and metal compounds contain metal halides and the like as reaction promoters.

  Examples of the organic oxygen absorber include hydroxy group-containing compounds, quinone compounds, double bond-containing compounds, and oxidizable resins. Oxygen can be absorbed by reacting oxygen with the hydroxyl group and double bond contained in these. The organic oxygen absorber is preferably a ring-opened polymer of a cycloalkene such as polyoctenylene, a conjugated diene polymer such as butadiene, and a cyclized product thereof.

  The content of such an oxygen absorbent (E) is usually 1 to 30% by weight, preferably 3 to 25% by weight, more preferably 5 to 20% by weight, based on EVOH (A). is there.

<Other additives (F)>
In the resin composition of the present invention, in addition to the above components, ethylene glycol, as needed, within the range not impairing the effects of the present invention (for example, at 5% by weight or less of the entire resin composition) Plasticizers such as aliphatic polyhydric alcohols such as glycerin and hexanediol; Higher fatty acids (eg, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, etc.), higher fatty acid metals other than metal salts (B) Salts (aluminum salts of higher fatty acids such as stearic acid, calcium salts, magnesium salts, barium salts, etc.), higher fatty acid esters (methyl esters of higher fatty acids, isopropyl esters, butyl esters, octyl esters etc.), higher fatty acid amides (stearic acid Amides, saturated aliphatic amides such as behenic acid amide, oleic acid amide, erucic acid amide, etc. Saturated fatty acid amide, ethylenebisstearic acid amide, ethylenebisoleic acid amide, ethylenebiserucic acid amide, bisfatty acid amides such as ethylenebislauric acid amide, low molecular weight polyolefin (eg, low molecular weight polyethylene having a molecular weight of about 500 to 10,000, or Low molecular weight polypropylene) Lubricants such as fluorinated ethylene resin; Anti blocking agent; Antioxidant; Colorant; Antistatic agent; Antibacterial agent; Insoluble inorganic salts (eg hydrotalcite etc), metal salts (B) other than Hydrate-forming metal salts; (eg, disodium succinate, sodium tartrate, sodium citrate, calcium citrate, zinc citrate, magnesium citrate etc. carboxylates such as sodium sulfate, potassium sulfate, magnesium sulfate etc. Sulfates, etc.), surfactants It can be appropriately added known additives such as conjugated polyene compound.

  The base resin in the whole resin composition of the present invention is EVOH (A). Accordingly, the amount of EVOH (A) is usually 70% by weight or more, preferably 80% by weight or more, and particularly preferably 90% by weight or more, based on the entire resin composition. If the amount is too small, the gas barrier properties tend to be reduced.

<Method of Preparing Resin Composition>
The method for producing the resin composition of the present invention is not particularly limited, and the metal salt (B) may be present on the inner and / or outer surface of the resin composition.

"Method of causing metal salt (B) to be present in resin composition"
Specifically, as a method of causing the metal salt (B) to be present inside the resin composition, a method in which the components (A) and (A) and (B) are mixed together and then melt-kneaded, (A) (A) And (B) a method of uniformly dissolving and mixing the component (B) in a dissolvable solvent and then removing the solvent, and the like, and the method of (A) is preferably used in industry. Although described in more detail, it is not limited thereto.

  The melt-kneading method in the above (a) can be carried out using, for example, a known melt-kneading apparatus such as a kneader ruder, extruder, mixing roll, Banbury mixer, plasto mill, etc. Is preferably melt-kneaded at 150 to 300 ° C. (more preferably 180 to 280 ° C.) for about 1 to 20 minutes, and in particular, it is industrially preferable in that pellets can be easily obtained using a single- or twin-screw extruder. It is also advantageous to provide a vent suction device, a gear pump device, a screen device, etc., if necessary. In particular, in order to remove moisture and by-products (such as low-molecular weight thermal decomposition products), one or more vent holes are provided in the extruder to suction under reduced pressure or prevent oxygen from being mixed in the extruder. By continuously supplying an inert gas such as nitrogen into the hopper for the purpose of reducing the heat, it is possible to obtain a resin composition of excellent quality in which thermal coloring and thermal deterioration are reduced.

  Also, the method of supplying the melt-kneading apparatus such as an extruder is not particularly limited, and 1) a method of dry-blending the components (A) and (B) and collectively supplying them to the extruder, 2) (a) A) A method of supplying the solid component (B) to the place where the component A is supplied and melted (solid side feed method), 3) where the component A is supplied and melted the extruder Among them, the method (1) is practical in view of the simplicity of the apparatus, the cost of the blend and the like.

  The resin composition obtained by the above methods (A) and (A) can directly obtain a melt-molded article after melt-kneading the raw material, but from the viewpoint of industrial handling, the melt-kneading is preferable. Thereafter, it is preferable to prepare a resin composition pellet and subject it to a melt molding method to obtain a melt molded article. From the economical point of view, a method of melt-kneading using an extruder, extruding in a strand form, and cutting and pelletizing this is preferable.

  The shape of the above-mentioned pellet is, for example, spherical, oval, cylindrical, cubic, rectangular or the like, but usually it is oval or cylindrical, and its size is convenience when it is used as a molding material later From the viewpoint of the oval, the diameter is usually 1 to 6 mm, preferably 2 to 5 mm, the height is usually 1 to 6 mm, preferably 2 to 5 mm, and in the case of a cylindrical shape, the diameter of the bottom is usually It is 1 to 6 mm, preferably 2 to 5 mm, and the length is usually 1 to 6 mm, preferably 2 to 5 mm.

  The water content of the resin composition or pellets is preferably 0.001 to 5% by weight (more preferably 0.01 to 2% by weight, particularly 0.1 to 1 part by weight), If the ratio is too low, the long-run formability tends to decrease. On the contrary, if it is too high, foaming may occur during extrusion, which is not preferable.

"Method of causing metal salt (B) to exist on the outer surface of resin composition"
Subsequently, as a method of causing the metal salt (B) to exist on the outer surface of the resin composition, specifically, (1) blending the component (B) with EVOH (A) having a water content of 0.1 to 5% by weight (2) a method of blending the melted component (B) with heated EVOH (A), (3) a method of blending the component (B) with EVOH (A) mixed with a small amount of silicone oil, etc. (4) A method of blending the component (B) with EVOH (A) containing a liquid plasticizer such as glycerin, (5) a method of blending the component (B) dissolved in a small amount of solvent into the EVOH (A) And the like, but the method of (1) is preferably adopted in industry, and the method will be described more specifically, but it is not limited thereto.

  When the component (B) is attached to the surface of the resin composition, the water content of such pellets is 0.1 to 5% by weight (more preferably 0.5 to 4) in order to improve the adhesion of the component (B). It is preferable to adjust to a weight%, particularly 1 to 3 weight%, and when the water content is less than 0.1 weight%, the component (B) is easily detached and the adhesion (attachment) distribution becomes uneven, and the reverse When it exceeds 5% by weight, the component (B) is coagulated and the adhesion (adhesion) distribution is also uneven at this time, which is not preferable.

In addition, about the moisture content of the resin composition pellet said here, it measures and calculates by the following method.
[Measuring method of moisture content]
The resin composition pellet is weighed by an electronic balance (W1: unit g), placed in a hot-air oven type dryer maintained at 150 ° C., dried for 5 hours, and further allowed to cool for 30 minutes in a desiccator Similarly, the weight of the toner is weighed (W2: unit g) and calculated from the following equation (1).
[Equation 1]
Moisture content (%) = {(W1-W2) / W1} × 100 (1)

  The blend can also be attached using known mixing devices such as rocking mixers, ribbon blenders, line mixers and the like.

<Multilayer structure>
A layer composed of the resin composition of the present invention (hereinafter simply referred to as a “resin composition layer” means a layer composed of the resin composition of the present invention) is laminated with another substrate to form a multilayer structure In addition, it is possible to further increase the strength and to provide other functions.

  As said base material, the layer (henceforth "a thermoplastic resin (C) layer") which consists of said other thermoplastic resin (C) is used preferably. The base material may be provided in a plurality of layers as needed.

As the other thermoplastic resin (C), it is possible to use the same resin as described above.
Among the above-mentioned other thermoplastic resins (C), polyamide resins are preferable as the substrate from the viewpoint of flexibility and stretchability, and in consideration of hydrophobicity, polyethylene resins which are relatively hydrophobic resins. Resins, polyolefin resins such as polypropylene resins, polycyclic olefin resins and unsaturated carboxylic acid-modified polyolefin resins thereof, polyester resins, polystyrene resins are preferable, and polyamide resins and polyolefin resins are more preferable. In particular, polyamide resins and polycyclic olefin resins are preferably used. These can be used alone or in combination of two or more.

  As said polyamide-type resin, the same thing as the above can be used. It is preferably a terminal-modified polyamide resin.

  When a polyamide resin layer is provided on at least one surface of the resin composition layer of the present invention, a multilayer structure having excellent flexibility and stretchability tends to be obtained.

In addition, it is also preferable to use a layer made of an adhesive resin (hereinafter, simply referred to as “adhesive resin layer”) between the resin composition layer and the other thermoplastic resin (C) layer. When a thermoplastic resin layer other than EVOH (A) is provided on at least one surface of the resin composition layer of the present invention via an adhesive resin layer, a multilayer structure having good water resistance tends to be obtained. .
A well-known thing can be used as said adhesive resin, and what is necessary is just to select suitably according to the kind of other thermoplastic resin (C) layer used as a base material. Typically, there can be mentioned a modified polyolefin polymer containing a carboxyl group obtained by chemically bonding an unsaturated carboxylic acid or its anhydride to a polyolefin resin by an addition reaction, a graft reaction or the like. For example, maleic anhydride graft modified polyethylene, maleic anhydride graft modified polypropylene, maleic anhydride graft modified ethylene-propylene (block and random) copolymer, maleic anhydride graft modified ethylene-ethyl acrylate copolymer, maleic anhydride graft Modified ethylene-vinyl acetate copolymer, maleic anhydride modified polycyclic olefin resin, maleic anhydride graft modified polyolefin resin, etc. can be used singly or in combination of two or more.

  In the other thermoplastic resin (C) layer and the adhesive resin layer, known plasticizers can be used within a range not impairing the gist of the present invention (for example, 30 wt% or less, preferably 10 wt% or less), Fillers, clays (montmorillonite etc.), colorants, antioxidants, antistatic agents, lubricants, core materials, antiblocking agents, UV absorbers, waxes, etc. may be included.

The layer structure of the multilayer structure is α (α1, α2, ...) for the resin composition layer of the present invention, β (β1, β2, ...) for the adhesive resin layer, and other thermoplastic resins (C When the layer is γ (γ1, γ2, ...), α1 / β / α2, γ1 / β1 / α / β2 / γ2, γ1 / α / γ2, γ / β / α, α1 / β / α2 Any combination such as / β / γ is possible.
In particular, when a polyamide-based resin is used as the other thermoplastic resin (C) layer and the polyamide-based resin layer is δ (δ 1, δ 2,...), Other thermoplastic resins (C) other than the polyamide-based resin (.Gamma.1, .gamma.2,...), .Alpha ./. Beta./.delta., .Delta.1 / .beta ./. Alpha./.delta.2, .delta ./. Alpha.1 / .beta.2 / .alpha.2, .delta.1 / .beta.1 / .alpha ./. Beta.2 / .delta.2, .delta.1 / .alpha.1 / .beta. β / α2 / δ2, δ1 / β1 / α1 / β2 / α2 / β3 / δ2, γ / α / β / δ, δ1 / β / α / γ / δ2, δ / α1 / β2 / α2 / γ, δ1 / β1 / α / γ / β2 / δ2, δ1 / β1 / γ1 / α / γ2 / β2 / δ2, δ1 / α1 / β / α2 / γ / δ2, δ1 / β1 / α1 / γ1 / β2 / α2 / γ2 / γ2 / Any combination such as β3 / δ2 is possible.

  The lamination method in the case of producing the multilayer structure by laminating the resin composition of the present invention on the above-mentioned base material can be carried out by a known method. For example, a method of melt extruding another substrate on a film, sheet or the like of the resin composition of the present invention, a method of melt extruding a resin composition of the present invention to another substrate, conversely, a resin composition of the present invention Of co-extrusion of the product and another substrate, films (layers) made of the resin composition of the present invention and other substrates (layers) are respectively prepared, and these are organic titanium compounds, isocyanate compounds, polyester systems The method of carrying out dry lamination using well-known adhesives, such as a compound and a polyurethane compound, and the method of removing a solvent, after coating the solution of the resin composition of this invention on another base material etc. are mention | raise | lifted. Among these, the method of co-extrusion in consideration of cost and environment is preferable.

  The above multilayer structure is then subjected to a (heating) stretching treatment as required. The stretching treatment may be either uniaxial stretching or biaxial stretching, and in the case of biaxial stretching, it may be simultaneous stretching or sequential stretching. Further, as the stretching method, a roll stretching method, a tenter stretching method, a tubular stretching method, a stretch blow method, a vacuum pressure air forming, or the like having a high stretch ratio can be employed. The stretching temperature is usually selected in the range of about 40 to 170 ° C., preferably about 60 to 160 ° C. When the stretching temperature is too low, the stretchability becomes poor, and when it is too high, it becomes difficult to maintain a stable stretched state.

  Heat setting may be performed subsequently for the purpose of imparting dimensional stability after stretching. The heat setting can be carried out by a known means. For example, the stretched multilayer structure (stretched film) is usually kept at a tension of 80 to 180 ° C., preferably 100 to 165 ° C., usually for about 2 to 600 seconds while maintaining tension. Perform heat treatment.

  Moreover, when using the multilayer stretched film obtained by using the resin composition of this invention as a film for shrinking, in order to provide heat-shrinkability, said heat setting is not performed, for example, the film after extending | stretching The cold air may be applied to the air to cool and fix the air.

  Furthermore, in some cases, it is also possible to obtain a cup- or tray-like multilayer container from the multilayer structure of the present invention. As a method of producing the multi-layered container, a draw forming method is usually adopted, and specifically, a vacuum forming method, a pressure forming method, a vacuum pressure forming method, a plug assist type vacuum pressure forming method and the like can be mentioned. Furthermore, in the case of obtaining a multilayer container in the form of a tube or a bottle from a multilayer parison (a hollow tubular preform before blow), a blow molding method is employed, specifically an extrusion blow molding method (double head type, mold moving type) Parison shift type, rotary type, accumulator type, horizontal parison type etc., cold parison type blow molding method, injection blow molding method, biaxial stretch blow molding method (extrusion type cold parison biaxial stretch blow molding method, injection type Examples include cold parison biaxial stretch blow molding, injection molding in-line biaxial stretch blow molding, and the like. The multilayer laminate of the present invention may be subjected to heat treatment, cooling treatment, rolling treatment, printing treatment, dry lamination treatment, solution or melt coating treatment, bag-making processing, deep drawing processing, box processing, tube processing, split processing, etc. It can be done.

  The thickness of the multilayer structure (including stretched ones) of the present invention, and further, the thickness of the resin composition layer constituting the multilayer structure, the polyamide resin layer, the adhesive resin layer, and the other thermoplastic resin layers It is appropriately set according to the configuration, the type of thermoplastic resin, the type of polyamide resin, the type of adhesive resin, the application and packaging form, the required physical properties and the like. In addition, the following numerical value is the value which totaled the thickness of the layer of the same kind, when two or more layers of at least 1 type exist among a resin composition layer, an adhesive resin layer, and other thermoplastic resin layers. is there.

  The thickness of the multilayer structure (including the stretched one) of the present invention is usually 10 to 5000 μm, preferably 30 to 3000 μm, and particularly preferably 50 to 2000 μm. If the total thickness of the multilayer structure is too thin, the gas barrier properties may be reduced. In addition, when the total thickness of the multilayer structure is too thick, the gas barrier properties become excessive, and unnecessary raw materials are used, which tends to be uneconomical. The resin composition layer is usually 1 to 500 μm, preferably 3 to 300 μm, particularly preferably 5 to 200 μm, and the other thermoplastic resin layer is usually 5 to 30000 μm, preferably 10 to 20000 μm, particularly preferably 20 The adhesive resin layer is generally 0.5 to 250 μm, preferably 1 to 150 μm, and particularly preferably 3 to 100 μm.

  Furthermore, the thickness ratio between the resin composition layer and the other thermoplastic resin layer in the multilayer structure (resin composition layer / other thermoplastic resin layer) is the thickness ratio between the thickest layers when there are a plurality of layers. The ratio is usually 1/99 to 50/50, preferably 5/95 to 45/55, and particularly preferably 10/90 to 40/60. In addition, the thickness ratio of the resin composition layer to the polyamide resin layer in the multilayer structure (resin composition layer / polyamide resin layer) is usually 10 in the ratio of the thickest layers when there are a plurality of layers. / 90 to 99/1, preferably 20/80 to 80/20, particularly preferably 40/60 to 60/40. In addition, the thickness ratio of the resin composition layer to the adhesive resin layer in the multilayer structure (resin composition layer / adhesive resin layer) is usually 10, in the ratio of the thickest layers when there are a plurality of layers. / 90 to 99/1, preferably 20/80 to 95/5, particularly preferably 50/50 to 90/10.

  The film obtained as described above, a bag made of stretched film, a container made of a stretched film, a cup, a tray, a tube, a bottle, etc., as well as general foods, may be seasonings such as mayonnaise and dressing, miso etc. It is useful as various packaging material containers, such as fermented foods, fats and oils, such as salad oil, beverages, cosmetics, and pharmaceuticals.

  Among them, the multilayer structure having a layer made of the resin composition of the present invention is improved in color tone deterioration at the time of melt molding, and appearance defects, in particular, reduction in image sharpness is reduced. This is because, in the multilayer structure, at the laminate interface of the resin composition layer / adhesive resin layer and / or the resin composition layer / polyamide resin layer, fine interface roughness which causes appearance defects is reduced. It is thought that it is for. This includes general foods, seasonings such as mayonnaise and dressings, fermented foods such as miso, fats and oils such as salad oil, soups, beverages, cosmetics, pharmaceuticals, detergents, cosmetics, industrial chemicals, agricultural chemicals, fuels, etc. It is useful as a container. In particular, semi-solid foods and seasonings such as mayonnaise, ketchup, sauce, miso, wasabi, mustard, grilled meat etc., salad oil, mirin, sake, beer, wine, juice, tea, sports drinks, mineral water, milk Bottles and tubes for liquid beverages and seasonings, etc., fruit, jelly, pudding, yogurt, mayonnaise, miso, processed rice, cooked foods, cups for semi-solid foods and seasonings such as soup It is useful as a packaging material for a wide container, raw meat, processed meat products (ham, bacon, wine etc.), cooked rice, and a wide-mouthed container for pet food.

  EXAMPLES Hereinafter, the present invention will be more specifically described by way of examples. However, the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the examples, "parts" are by weight.

Example 1
<Production of Resin Composition>
Ethylene-vinyl alcohol coweight of EVOH (a1) [content of ethylene structural unit: 38 mol%, degree of saponification 99.6 mol%, MFR 4.2 g / 10 min (210 ° C., load 2160 g)] as EVOH (A) As a pellet, as a metal salt (B), 0.06 parts of zinc gluconate trihydrate (b1) was used with respect to 100 parts of EVOH (a1). By blending EVOH (a1) pellets and zinc gluconate trihydrate (b1) and dry blending all at once, then by melt-kneading and pelletizing with a 20 mmφ twin-screw extruder (L / D = 25) The resin composition of the present invention was prepared.

<Manufacturing of multilayer structure>
Resin composition prepared above, linear low density polyethylene (LLDPE) ("UF240" manufactured by Japan Polyethylene Corporation, MFR 2.1 g / 10 min (190 ° C, load 2160 g)), adhesive resin (LyondellBasell Corporation "PLEXAR" Multi-layer co-extrusion molding is performed under the following conditions using a three-kind five-layer multi-layer co-extrusion cast film forming apparatus using “PX 3236”, MFR 2.0 g / 10 min (190 ° C., load 2160 g)), LLDPE layer / adhesion A multilayer structure (film) having a three-kind five-layer structure of a conductive resin layer / EVOH layer / adhesive resin layer / LLDPE layer was obtained. The thickness (μm) of each layer of the multilayer structure was LLDPE layer / adhesive resin layer / EVOH layer / adhesive resin layer / LLDPE layer = 37.5 / 5/15/5 / 37.5. The molding apparatus die temperatures were all set at 210.degree.

(Multilayer coextrusion molding conditions)
・ Interlayer extruder (EVOH): 40 mmφ single screw extruder (barrel temperature: 210 ° C)
Upper and lower layer extruder (LLDPE): 40 mm φ single screw extruder (barrel temperature: 210 ° C.)
・ Middle upper and lower layer extruder (adhesive resin): 32 mmφ single screw extruder (barrel temperature: 210 ° C)
・ Die: 3-layer 5-layer feed block type T die (die temperature: 210 ° C)
-Take-up speed: 14 m / min-Roll temperature: 50 ° C

<Image clarity of multilayer structure>
The image sharpness of the multilayer structure produced above was evaluated by image sharpness measurement (optical comb: 0.5 mm) according to JIS K 7374 "Plastic-Determination of image sharpness". The film test pieces were measured with the film machine direction as the vertical direction. As a measuring instrument, an ICM-1 image clarity measuring instrument manufactured by Suga Test Instruments Co., Ltd. was used.
The higher the image definition, the better the transparency. The results of evaluation according to the following criteria are shown in Table 1.
◎: The image definition is 80% or more.
○: The image definition is 70 to 79%.
X: The image definition is less than 70%.

<Appearance of multilayer structure>
The appearance of the multilayer structure produced above was visually evaluated according to the following evaluation criteria.
◎: The appearance is very good.
○: The appearance is good.
X: The appearance is bad (granular lumps can be confirmed).

Example 2
A resin composition and a multilayer structure were produced in the same manner as in Example 1 except that 0.1 part of zinc gluconate trihydrate (b1) was used relative to 100 parts of EVOH (a1). The image sharpness and appearance of the obtained multilayer structure were evaluated in the same manner as in Example 1.

[Example 3]
A resin composition and a multilayer structure were produced in the same manner as in Example 1 except that 0.18 parts of zinc gluconate trihydrate (b1) was used with respect to 100 parts of EVOH (a1). The image sharpness and appearance of the obtained multilayer structure were evaluated in the same manner as in Example 1.

Example 4
A resin composition and a multilayer structure were produced in the same manner as in Example 1 except that 1 part of zinc gluconate trihydrate (b1) was used relative to 100 parts of EVOH (a1). The image sharpness and appearance of the obtained multilayer structure were evaluated in the same manner as in Example 1.

[Example 5]
A resin composition and a multilayer structure were produced in the same manner as in Example 1 except that 0.06 parts of calcium gluconate monohydrate (b2) was used with respect to 100 parts of EVOH (a1). The image sharpness and appearance of the obtained multilayer structure were evaluated in the same manner as in Example 1.

[Example 6]
A resin composition and a multilayer structure were produced in the same manner as in Example 1 except that 0.06 parts of magnesium gluconate dihydrate (b3) was used with respect to 100 parts of EVOH (a1). The image sharpness and appearance of the obtained multilayer structure were evaluated in the same manner as in Example 1.

Comparative Example 1
A resin composition and a multilayer structure are carried out in the same manner as in Example 1 except that zinc gluconate trihydrate (b1) is not blended and 0.06 parts of stearic acid per 100 parts of EVOH (a1) is used. The body was made. The image sharpness and appearance of the obtained multilayer structure were evaluated in the same manner as in Example 1.

Comparative Example 2
A resin composition and a multilayer structure are carried out in the same manner as in Example 1 except that zinc gluconate trihydrate (b1) is not blended, and calcium stearate is used in an amount of 0.06 parts to 100 parts of EVOH (a1). The body was made. The image sharpness and appearance of the obtained multilayer structure were evaluated in the same manner as in Example 1.

Comparative Example 3
A resin composition and a multilayer were prepared in the same manner as in Example 1 except that zinc gluconate trihydrate (b1) was not blended, and sodium stearate was used in an amount of 0.06 parts to 100 parts of EVOH (a1). A structure was produced. The image sharpness and appearance of the obtained multilayer structure were evaluated in the same manner as in Example 1.

Comparative Example 4
A resin composition was prepared in the same manner as in Example 1 except that zinc gluconate trihydrate (b1) was not blended, and 0.06 parts of ethylenebisstearic acid amide was used with respect to 100 parts of EVOH (a1). And a multilayer structure was made. The image sharpness and appearance of the obtained multilayer structure were evaluated in the same manner as in Example 1.

Comparative Example 5
A resin was prepared in the same manner as in Example 1 except that zinc gluconate trihydrate (b1) was not blended and 0.06 parts of calcium citrate tetrahydrate was used with respect to 100 parts of EVOH (a1). Compositions and multilayer structures were made. The image sharpness and appearance of the obtained multilayer structure were evaluated in the same manner as in Example 1.

Comparative Example 6
A resin was prepared in the same manner as in Example 1 except that zinc gluconate trihydrate (b1) was not blended and 0.06 parts of zinc citrate dihydrate was used with respect to 100 parts of EVOH (a1). Compositions and multilayer structures were made. The image sharpness and appearance of the obtained multilayer structure were evaluated in the same manner as in Example 1.

Comparative Example 7
A resin composition and a multilayer structure were produced in the same manner as in Example 1 except that zinc gluconate trihydrate was not used. The image sharpness and appearance of the obtained multilayer structure were evaluated in the same manner as in Example 1.

  From the above results, in Examples 1 to 6 of the multilayer structure manufactured using the resin composition containing EVOH (A) and the metal salt (B), the image definition of the multilayer structure is high and the appearance is good It can be seen that it is.

  On the other hand, Comparative Examples 1 to 7 of the multilayer structure manufactured using the resin composition not containing the metal salt (B) have insufficient image definition and / or appearance of the multilayer structure. I understand.

  The present invention is a resin composition containing EVOH (A) and a metal salt of a monovalent carboxylic acid (B) having a hydroxyl group and having 2 to 17 carbon atoms, and a multilayer obtained by using this resin composition. The structure has a high image definition of the multilayer structure and a good appearance. From this, it is useful as various packaging materials of foodstuffs, especially a container for alcoholic beverages. The multi-layered structure comprising the resin composition of the present invention can be used as a general food, as well as seasonings such as mayonnaise and dressing, fermented foods such as miso, fats and oils such as salad oil, various packages such as beverages, cosmetics and pharmaceuticals. It is useful as a raw material for material containers.

Claims (5)

  A resin composition comprising an ethylene-vinyl alcohol copolymer (A) and a metal salt of a monovalent carboxylic acid (B) having a hydroxy group and having 2 to 17 carbon atoms.   The resin composition according to claim 1, wherein the content of the metal salt (B) is 0.01 to 5 parts with respect to 100 parts of the ethylene-vinyl alcohol copolymer (A).   The said metal salt (B) is a saturated hydrate, The resin composition of Claim 1 or 2 characterized by the above-mentioned.   A thermoplastic resin other than ethylene-vinyl alcohol copolymer (A) on at least one surface of a layer comprising the resin composition according to any one of claims 1 to 3 via an adhesive resin layer. A multilayer structure characterized by having a layer.   A multilayer structure having a polyamide resin layer on at least one surface of a layer comprising the resin composition according to any one of claims 1 to 3.