JP7444713B2 - Resin composition, method for producing the same, molded product and laminate - Google Patents

Description

The present invention relates to a resin composition, a method for producing the same, a molded article, and a laminate.

In general, ethylene-vinyl alcohol copolymers (hereinafter also referred to as "EVOH") have excellent transparency, gas barrier properties, fragrance retention, solvent resistance, oil resistance, and the like. Taking advantage of these characteristics, EVOH is used in films, sheets, containers, etc., as packaging materials for foods, pharmaceuticals, industrial chemicals, agricultural chemicals, and the like. EVOH is also used for applications such as fuel tanks for automobiles and other vehicles, tire tube materials, agricultural films, geomembranes, and shoe cushioning materials due to its barrier properties, heat retention properties, and stain resistance. ing.

EVOH has low thermal stability compared to other resins, and may produce lumps during heat treatment and molding. Furthermore, when EVOH is exposed to light, heat, etc. due to outdoor use, its mechanical strength may decrease. Regarding the thermal stability of EVOH, Patent Document 1 states that it contains ethylene units (III), vinyl alcohol units (IV) and vinyl ester units (V), and the ratio of ethylene units (III) to the total of the above units (III+IV+V). is 20 to 60 mol%, and the ratio of the total (I+II) of carboxylic acid units (I) and lactone ring units (II) at the polymer terminal of the copolymer to the total of the above units (III+IV+V) is 0.12 mol% or less EVOH is described. According to Patent Document 1, EVOH with a small number of terminal carboxylic acid units and lactone ring units is said to be less likely to cause lumps during heat treatment and molding, and to improve long-run performance during melt molding.

International Publication No. 2004/092234

However, the EVOH of Patent Document 1 has a total ratio (I+II) of carboxylic acid units (I) and lactone ring units (II) of 0.12 mol% or less, and EVOH with a high total ratio It has not been possible to improve the stability, that is, to suppress the bumps that occur during heat treatment and molding. Further, the EVOH of Patent Document 1 does not take into consideration heat resistance and light resistance in consideration of long-term outdoor use. Furthermore, in recent years, discarded plastic products are flowing into the ocean, turning into microplastics and polluting the ocean, which has become a problem. For this reason, there is a need to develop resins that are difficult to turn into microplastics. In particular, as shown in Table 11 (Reference Comparative Examples 18 to 20) of Examples described below, the sum of carboxylic acid units (I) and lactone ring units (II) such as EVOH of Patent Document 1 The inventors have found that materials with a low ratio of (I+II) are more likely to become microplastics.

On the other hand, the characteristics of EVOH such as thermal stability, heat resistance and light resistance are influenced by the structure of EVOH itself such as ethylene content. Therefore, it is possible to some extent to improve thermal stability, heat resistance, light resistance, etc. by adjusting the ethylene content and the like. However, since EVOH having a suitable ethylene content etc. depending on the purpose of the molded article is usually used, it is possible to improve various properties such as thermal stability, heat resistance and light resistance without changing the EVOH itself. is desired.

Further, for EVOH or a resin composition containing EVOH, from the viewpoint of productivity, it is desirable that the discharge amount during melt molding be large and that discoloration such as yellowing in the obtained molded product be suppressed. However, the EVOH of Patent Document 1 does not take these points into particular consideration.

The present invention was made based on the above-mentioned circumstances, and its purpose is to provide a molded article that suppresses the occurrence of lumps during melt molding, has sufficient heat and light resistance, and is difficult to turn into microplastics after disposal. is a resin composition that can be obtained, and the above characteristics are sufficiently improved compared to those using the same EVOH, and a molded article with a large discharge amount during melt molding and suppressed discoloration is obtained. An object of the present invention is to provide a resin composition capable of producing a resin composition, a method for producing the resin composition, and a molded article and a laminate using the resin composition.

According to the invention, the above objectives are:
[1] A resin composition containing an ethylene-vinyl alcohol copolymer (A), an aluminum ion (B), and a nonionic surfactant (N), the resin composition containing at least one of the ethylene-vinyl alcohol copolymer (A) A portion thereof has at least one of a carboxylic acid unit (I) and a lactone ring unit (II) located at the terminal end of the polymer, and the carboxylic acid unit (I) and The total content (i+ii) of lactone ring units (II) is 14 μmol/g or more and 78 μmol/g or less, and the content (b) of aluminum ions (B) per 1 g of ethylene-vinyl alcohol copolymer (A) is 0.002 μmol/g or more and 0.17 μmol/g or less, and the content (n) of the nonionic surfactant (N) relative to the ethylene-vinyl alcohol copolymer (A) is 0.1 ppm or more and 1,000 ppm or less. A resin composition;
[2] The ratio ((i+ii)/b) of the total content (i+ii) of carboxylic acid units (I) and lactone ring units (II) to the content (b) of aluminum ions (B) is 180 or more and 20 ,000 or less, the resin composition of [1];
[3] The resin composition of [1] or [2], in which the aluminum ion (B) is derived from a fatty acid aluminum salt having 5 or less carbon atoms;
[4] Further contains at least one compound (C) selected from the group consisting of cinnamic acids and conjugated polyene compounds with a molecular weight of 1,000 or less, and the content of the compound (C) in the ethylene-vinyl alcohol copolymer (A). The resin composition according to any one of [1] to [3], wherein the amount (c) is 1 ppm or more and 1,000 ppm or less;
[5] The ratio (ii/(i+ii)) of the content (ii) of the lactone ring unit (II) to the total content (i+ii) of the carboxylic acid unit (I) and the lactone ring unit (II) is 40 mol% or more. The resin composition according to any one of [1] to [4];
[6] The nonionic surfactant (N) of [1] to [5], wherein the nonionic surfactant (N) is at least one type selected from the group consisting of an ether type, an aminoether type, an ester type, an ester/ether type, and an amide type. Any resin composition;
[7] The nonionic surfactant (N) is polyoxyalkylene alkyl ether, polyoxyalkylene alkenyl ether, polyoxyethylene styrenated phenyl ether, polyoxyalkylene alkylamine, polyoxyalkylene alkenylamine, polyoxyalkylene alkyl ester , polyoxyalkylene alkenyl ester, sorbitan alkyl ester, sorbitan alkenyl ester, polyoxyethylene sorbitan alkyl ester, polyoxyethylene sorbitan alkenyl ester, glycerol alkyl ester, glycerol alkenyl ester, polyglycerin alkyl ester, polyglycerin alkenyl ester and higher fatty acid amide The resin composition according to any one of [1] to [6], which is at least one selected from the group consisting of;
[8] Furthermore, it contains at least one additive selected from the group consisting of antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, and fillers from 0.005% by mass to 50% by mass. , the resin composition of any one of [1] to [7];
[9] A molded article formed from the resin composition of any one of [1] to [8];
[10] A laminate comprising a layer made of the resin composition according to any one of [1] to [8] and at least one other layer;
[11] Production of a resin composition according to any one of [1] to [8], comprising a step of melt-kneading a mixture containing an ethylene-vinyl alcohol copolymer (A), a nonionic surfactant (N), and water. Method;
[12] The method for producing a resin composition according to [11], wherein the content of water in the mixture is 0.1 parts by mass or more and 50 parts by mass or less based on 100 parts by mass of the ethylene-vinyl alcohol copolymer (A);
[13] Further comprising a step of obtaining the above mixture by adding an aqueous solution or aqueous dispersion containing the nonionic surfactant (N) to the ethylene-vinyl alcohol copolymer (A), [11] or [12] A method for producing a resin composition;
This is achieved by providing one of the following:

According to the present invention, it is a resin composition that suppresses the occurrence of lumps during melt molding, has sufficient heat resistance and light resistance, and provides molded products that are difficult to turn into microplastics after disposal, and is similar to those using the same EVOH. A resin composition which has sufficiently improved each of the above-mentioned properties in comparison, has a large discharge amount during melt molding, and can obtain a molded article with suppressed coloring, a method for producing this resin composition, and Molded bodies and laminates using this resin composition can be provided.

Solvent: DMSO-d ₆ Measurement temperature: ¹ H-NMR spectrum of EVOH-A of Synthesis Example 1 measured at 25°C. Solvent: DMSO-d ₆ Measurement temperature: ¹ H-NMR spectrum of EVOH-A of Synthesis Example 1 measured at 80°C. Solvent: D ₂ O + MeOD Measurement temperature: ¹ H-NMR spectrum of EVOH-A of Synthesis Example 1 measured at 80°C.

<Resin composition>
The resin composition of the present invention contains an ethylene-vinyl alcohol copolymer (A) (hereinafter sometimes referred to as "EVOH (A)"), an aluminum ion (B), and a nonionic surfactant (N). contains. At least a portion of EVOH (A) has at least one of a carboxylic acid unit (I) and a lactone ring unit (II) located at the polymer terminal. The total content (i+ii) of carboxylic acid units (I) and lactone ring units (II) per 1 g of EVOH (A) is 14 μmol/g or more and 78 μmol/g or less. The content (b) of aluminum ions (B) per 1 g of EVOH (A) is 0.002 μmol/g or more and 0.17 μmol/g or less. The content (n) of the nonionic surfactant (N) relative to the ethylene-vinyl alcohol copolymer (A) is 0.1 ppm or more and 1,000 ppm or less.

The resin composition of the present invention is a resin composition that suppresses the occurrence of lumps during melt molding, has sufficient heat resistance and light resistance, and can obtain a molded product that is difficult to turn into microplastics after disposal, and is a resin composition that can be obtained using the same EVOH. Each of the above characteristics has been sufficiently improved compared to the original. Therefore, according to the resin composition of the present invention, the generation of lumps can be further suppressed without changing the type of EVOH, and the heat resistance and light resistance and resistance to microplasticization of the obtained molded product etc. can be improved. The reason why such an effect occurs is not clear, but it is assumed to be as follows. A stable structure is formed by a predetermined amount of aluminum ion (B) interacting with the carboxylic acid unit (I) and lactone ring unit (II) located at the terminal of EVOH (A). This suppresses gelation during melt molding, thereby suppressing the occurrence of lumps. It is also presumed that the resulting molded product has excellent heat and light resistance and is difficult to turn into microplastic after disposal, as a result of the above-mentioned stable structure being formed.

The resin composition of the present invention further contains a nonionic surfactant (N) in an amount of 0.1 ppm or more and 1,000 ppm or less based on the ethylene-vinyl alcohol copolymer (A), so that it can be melt-molded. The discharge amount of the resin composition can be increased. In particular, even if the resin composition contains components other than EVOH (A) and aluminum ions (B), the discharge amount of the resin composition can be increased without being affected by such components. In addition, a constant discharge amount can be ensured even when the molten resin is at a low temperature. Furthermore, surprisingly, by containing a predetermined amount of nonionic surfactant (N) in the resin composition of the present invention, coloring of the resin composition during melt molding is suppressed. Although the details of this reason are not clear, it is assumed that the reason is as follows. Generally, EVOH contains about 10 to 500 ppm of alkali metal ions and alkaline earth metal ions such as Na and Mg. It is known that when these metal ions are contained, the reaction between these metal ions and EVOH accelerates thermal deterioration of EVOH, causing coloration such as yellowing in EVOH. It is presumed that thermal deterioration of EVOH (A) is suppressed by inhibiting such a reaction by the nonionic surfactant (N), and as a result, a molded article with suppressed coloring is obtained.

The resin composition of the present invention may further contain components other than EVOH (A), aluminum ions (B), and nonionic surfactants (N). Each component of the resin composition of the present invention will be explained in detail below.

(EVOH(A))
EVOH (A) is a copolymer having ethylene units and vinyl alcohol units. EVOH (A) is usually obtained by a saponification reaction of an ethylene-vinyl ester copolymer. Therefore, EVOH (A) may further have residual vinyl ester units. That is, EVOH (A) is a copolymer having an ethylene unit and a vinyl alcohol unit, and further having or not having a vinyl ester unit as an arbitrary monomer unit. The production and saponification of the ethylene-vinyl ester copolymer can be carried out by known methods. Vinyl acetate is a typical vinyl ester, but other fatty acid vinyls such as vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versatate can also be used. It may also be an ester.

At least a portion of EVOH (A) has at least one of a carboxylic acid unit (I) and a lactone ring unit (II) located at the polymer terminal (main chain terminal). The carboxylic acid unit (I) is a structural unit located at the end of a polymer and has a carboxy group. The carboxylic acid unit (I) is also referred to as a terminal carboxylic acid unit. A part or all of the carboxy group possessed by the carboxylic acid unit (I) may exist in the form of a salt or an anion (-COO ^- ). The lactone ring unit (II) is a structural unit located at the end of the polymer and has a lactone ring. The lactone ring unit (II) is also referred to as a terminal lactone ring unit. The number of members of the lactone ring is not particularly limited, and may be, for example, a 4- to 6-membered ring, with a 5-membered ring being preferred. The carboxylic acid unit (I) may be, for example, a structural unit represented by the following formula (1). The lactone ring unit (II) may be a structural unit represented by the following formula (2), for example.

In formula (1), X is a hydrogen atom, a hydroxy group, or an esterified hydroxy group. Y is a hydrogen atom or a metal atom.

Examples of the esterified hydroxy group represented by X include -OCO-CH ₃ and -OCO-C ₂ H ₅ .

Examples of the metal atom represented by Y include alkali metals such as sodium, alkaline earth metals such as magnesium and calcium, typical metals such as aluminum, transition metals, and the like. Among these, typical elements are preferred, and alkali metals, alkaline earth metals, and aluminum are preferred. When Y is aluminum, this aluminum is included in the aluminum ion (B). When Y is a divalent or higher metal atom, two or more carboxylate anions (-COO ^- ) may be bonded or coordinated to one Y.

The total content (i+ii) of carboxylic acid units (I) and lactone ring units (II) per 1 g of EVOH (A), that is, the carboxylic acid units (I) and lactone ring units (II) present in 1 g of EVOH (A). ) The lower limit of the total amount (substance amount: number of moles) is 14 μmol/g, preferably 18 μmol/g, and more preferably 22 μmol/g. Further, the lower limit of the total content of carboxylic acid units (I) and lactone ring units (II) with respect to the total content of ethylene units, vinyl alcohol units, and vinyl ester units of EVOH (A) is preferably 0.10 mol%, 0.12 mol% is more preferable, and 0.14 mol% is even more preferable. When the total content of carboxylic acid units (I) and lactone ring units (II) is at least the above-mentioned lower limit, interaction with aluminum ions (B) will occur sufficiently, particularly improving microplasticization resistance.

On the other hand, the upper limit of the total content (i+ii) of carboxylic acid units (I) and lactone ring units (II) per 1 g of EVOH (A) is 78 μmol/g, preferably 70 μmol/g, and 60 μmol/g. More preferably, 50 μmol/g is even more preferred, and particularly preferably 40 μmol/g. Further, the upper limit of the total content of carboxylic acid units (I) and lactone ring units (II) with respect to the total content of ethylene units, vinyl alcohol units, and vinyl ester units of EVOH (A) is preferably 0.4 mol%, 0.3 mol% is more preferable, and 0.25 mol% is even more preferable. When there are too many carboxylic acid units (I) and lactone ring units (II), thermal stability decreases. Specifically, the carboxylic acid unit (I) and the lactone ring unit (II) can react with the hydroxy group of EVOH (A) at high temperatures to form a highly polymerized polymer having branches. Therefore, when the content of carboxylic acid units (I) and lactone ring units (II) is large, there is a tendency to reduce the melt moldability of EVOH (A). Therefore, when the total content of carboxylic acid units (I) and lactone ring units (II) is below the above upper limit, the generation of lumps during melt molding can be suppressed.

Ratio (ii/(i+ii)) of content (ii) of lactone ring unit (II) to total content (i+ii) of carboxylic acid unit (I) and lactone ring unit (II) of EVOH (A): lactone ring unit The lower limit of the ratio) may be, for example, 30 mol%, preferably 40 mol%, and more preferably 50 mol%. When the lactone ring unit ratio (ii/(i+ii)) is equal to or higher than the above lower limit, heat resistance and light resistance and microplasticization resistance tend to increase due to effective interaction with aluminum ions (B), etc. be. On the other hand, the upper limit of this lactone ring unit ratio (ii/(i+ii)) may be, for example, 90 mol%, 80 mol%, or 70 mol%.

The total content (i + ii) of carboxylic acid units (I) and lactone ring units (II) per 1 g of EVOH (A) is adjusted by, for example, polymerization conditions such as the type of polymerization initiator, drying conditions such as drying atmosphere, etc. Ru. In EVOH (A) which does not have a branched structure, the total content (i+ii) of carboxylic acid units (I) and lactone ring units (II) tends to be relatively small when the degree of polymerization is high. In many cases, it does not follow the trend. For example, as described in Patent Document 1, the total content (i+ii) of carboxylic acid units (I) and lactone ring units (II) can be reduced by contacting an ethylene-vinyl ester copolymer or EVOH with a reducing agent. can be reduced. Conversely, the total content of carboxylic acid units (I) and lactone ring units (II) can be reduced by contacting the ethylene-vinyl ester copolymer or EVOH with an oxidizing agent or by drying it in an atmosphere that easily oxidizes. It is also possible to increase the amount (i+ii). Furthermore, the ratio of the content (ii) of the lactone ring unit (II) to the total content (i+ii) of the carboxylic acid units (I) and the lactone ring unit (II) (ii/(i+ii): lactone ring unit ratio) is , can be adjusted by saponification conditions, etc. For example, if saponification is performed under conditions that promote saponification, the lactone ring unit ratio (ii/(i+ii)) tends to increase.

The total content (i+ii) of carboxylic acid units (I) and lactone ring units (II) located at the polymer terminal of EVOH (A) and the lactone ring unit ratio (ii/(i+ii)) are determined by ¹ H-NMR measurement. is required. The inventors have found that the above measurement results differ depending on the type of solvent used during the measurement. Therefore, the above measurement is performed using a mixed solvent of water/methanol (mass ratio 4/6, however, if the sample does not dissolve, the mass ratio is changed as appropriate). Specifically, the total content (i+ii) of carboxylic acid units (I) and lactone ring units (II) and the lactone ring unit ratio (ii/(i+ii)) were measured by the method described in the Examples below. value.

The lower limit of the content of ethylene units in EVOH (A) is preferably 10 mol%, more preferably 15 mol%, even more preferably 20 mol%, and even more preferably 25 mol%. On the other hand, the upper limit of the content of ethylene units in EVOH (A) is preferably 60 mol%, more preferably 55 mol%, and even more preferably 50 mol% or 45 mol%. By setting the content of ethylene units to the above lower limit or more, thermal stability, microplasticization resistance, etc. tend to improve. Furthermore, by controlling the content of ethylene units to be less than or equal to the above upper limit, oxygen barrier properties and the like tend to improve, and interlayer adhesion when a laminate is obtained also tends to improve.

The lower limit of the degree of saponification of EVOH (A) is preferably 90 mol%, more preferably 95 mol%, even more preferably 99 mol%, and particularly preferably 99.6 mol%. By setting the degree of saponification of EVOH (A) to the above-mentioned lower limit or more, melt moldability, gas barrier properties, heat resistance, light resistance, moisture resistance, etc. of the obtained molded product tend to be improved. Moreover, the degree of saponification may be 100 mol% or less, 99.97 mol% or less, or 99.94 mol% or less.

EVOH (A) contains carboxylic acid units (I), lactone ring units (II), and units derived from other monomers other than ethylene, vinyl ester, and saponified products thereof, to the extent that the effects of the present invention are not impaired. may have. The content of units derived from other monomers (units other than carboxylic acid units (I), lactone ring units (II), ethylene units, vinyl ester units, and vinyl alcohol units) with respect to the total structural units of EVOH (A) is It is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 10 mol% or less, even more preferably 5 mol% or less, and particularly preferably 1 mol% or less. Moreover, when EVOH (A) has units derived from the other monomers mentioned above, the content thereof may be 0.05 mol% or more, or 0.1 mol% or more.

Examples of other monomers include unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, and itaconic acid, or their anhydrides, salts, or mono- or dialkyl esters; nitriles such as acrylonitrile and methacrylonitrile; acrylamide and methacryl Amides such as amides; Olefin sulfonic acids or their salts such as vinyl sulfonic acid, allyl sulfonic acid, meta-allylsulfonic acid; vinyl trimethoxysilane, vinyl triethoxy silane, vinyl tri(β-methoxy-ethoxy) silane, γ-methacryloxy Vinyl silane compounds such as propylmethoxysilane; alkyl vinyl ethers, vinyl ketones, N-vinylpyrrolidone, vinyl chloride, vinylidene chloride and the like.

In addition, units derived from other monomers include a structural unit (X) represented by the following formula (I), a structural unit (Y) represented by the following formula (II), and a structural unit (Y) represented by the following formula (III). The structural unit (Z) may be at least one type of structural unit (Z).

In the above formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are each independently a hydrogen atom and have 1 to 10 carbon atoms. represents an aliphatic hydrocarbon group, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a hydroxyl group. One pair of R ¹ , R ² and R ³ , R ⁴ and R ⁵ , and R ⁶ and R ⁷ may be bonded (provided that one pair of R ¹ , R ² and R ³ are both hydrogen atoms). (excluding cases where R ⁴ and R ⁵ or R ⁶ and R ⁷ are both hydrogen atoms). In addition, some or all of the hydrogen atoms possessed by the aliphatic hydrocarbon group having 1 to 10 carbon atoms, the alicyclic hydrocarbon group having 3 to 10 carbon atoms, and the aromatic hydrocarbon group having 6 to 10 carbon atoms, It may be substituted with a hydroxyl group, an alkoxy group, a carboxyl group, or a halogen atom. In the above formula, R ¹² and R ¹³ each independently represent a hydrogen atom, a formyl group, or an alkanoyl group having 2 to 10 carbon atoms.

When EVOH (A) has a structural unit (X), (Y) or (Z), the flexibility and processing properties of the resin composition are improved, and the stretchability and thermoformability of the resulting molded article or multilayer structure are improved. etc. tend to be better.

In the structural unit (X), (Y) or (Z), examples of the aliphatic hydrocarbon group having 1 to 10 carbon atoms include an alkyl group and an alkenyl group. Examples of the alicyclic hydrocarbon group having 3 to 10 carbon atoms include a cycloalkyl group and a cycloalkenyl group. Examples of the aromatic hydrocarbon group having 6 to 10 carbon atoms include phenyl group.

In the structural unit (X), R ¹ , R ² and R ³ are each independently preferably a hydrogen atom, a methyl group, an ethyl group, a hydroxyl group, a hydroxymethyl group, and a hydroxyethyl group, and among them, the resulting multilayer structure, etc. From the viewpoint of further improving the stretchability and thermoformability in , a hydrogen atom, a methyl group, a hydroxyl group, and a hydroxymethyl group are each independently more preferable.

The method for incorporating the structural unit (X) into EVOH (A) is not particularly limited, and for example, in the polymerization of ethylene and vinyl ester, a method of copolymerizing a monomer derived from the structural unit (X), etc. Can be mentioned. Examples of monomers derived from the structural unit (X) include alkenes such as propylene, butylene, pentene, and hexene; 3-hydroxy-1-propene, 3-acyloxy-1-propene, and 3-acyloxy-1-butene; , 3-hydroxy-1-butene, 4-hydroxy-1-butene, 4-acyloxy-1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-hydroxy-1-butene, 4-acyloxy -3-hydroxy-1-butene, 3-acyloxy-4-methyl-1-butene, 4-acyloxy-2-methyl-1-butene, 4-acyloxy-3-methyl-1-butene, 3,4-diacyloxy -2-methyl-1-butene, 4-hydroxy-1-pentene, 5-hydroxy-1-pentene, 4,5-dihydroxy-1-pentene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene , 4,5-diasiloxy-1-pentene, 4-hydroxy-3-methyl-1-pentene, 5-hydroxy-3-methyl-1-pentene, 4,5-dihydroxy-3-methyl-1-pentene, 5 , 6-dihydroxy-1-hexene, 4-hydroxy-1-hexene, 5-hydroxy-1-hexene, 6-hydroxy-1-hexene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6 Examples include alkenes having a hydroxyl group or an ester group, such as -acyloxy-1-hexene and 5,6-diacyloxy-1-hexene. Among them, propylene, 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4-acyloxy-1 are preferred from the viewpoint of copolymerization reactivity, processability and gas barrier properties of the obtained molded bodies and multilayer structures. -butene and 3,4-diacyloxy-1-butene are preferred. Note that "acyloxy" is preferably acetoxy, and specifically 3-acetoxy-1-propene, 3-acetoxy-1-butene, 4-acetoxy-1-butene and 3,4-diacetoxy-1-butene are preferred. In the case of an alkene having an ester, it is induced into the structural unit (X) during the saponification reaction.

In the structural unit (Y), both R ⁴ and R ⁵ are preferably hydrogen atoms. In particular, it is more preferable that both R ⁴ and R ⁵ are hydrogen atoms, one of R ⁶ and R ⁷ is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, and the other is a hydrogen atom. As the aliphatic hydrocarbon group, an alkyl group and an alkenyl group are preferred. From the viewpoint of placing particular emphasis on the gas barrier properties of the obtained molded article and multilayer structure, it is more preferable that one of R ⁶ and R ⁷ is a methyl group or an ethyl group, and the other is a hydrogen atom. Further, it is more preferable that one of R ⁶ and R ⁷ is a substituent represented by (CH ₂ ) _h OH (where h is an integer of 1 to 8), and the other is a hydrogen atom. Note that h is preferably an integer of 1 to 4, more preferably 1 or 2, and even more preferably 1.

The method of incorporating the structural unit (Y) into EVOH (A) is not particularly limited, and a method of reacting a monovalent epoxy compound with EVOH obtained by a saponification reaction is used. As the monovalent epoxy compound, compounds represented by the following formulas (IV) to (X) are preferably used.

In the above formula, R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms (alkyl group, alkenyl group, etc.), or 3 carbon atoms. Represents an alicyclic hydrocarbon group having ~10 carbon atoms (cycloalkyl group, cycloalkenyl group, etc.) or an aliphatic hydrocarbon group having 6 to 10 carbon atoms (phenyl group, etc.). Further, i, j, k, p and q each independently represent an integer of 1 to 8. However, when R ¹⁷ is a hydrogen atom, R ¹⁸ has a substituent other than a hydrogen atom.

Examples of the monovalent epoxy compound represented by formula (IV) include epoxyethane (ethylene oxide), epoxypropane, 1,2-epoxybutane, 2,3-epoxybutane, 3-methyl-1,2-epoxybutane , 1,2-epoxypentane, 3-methyl-1,2-epoxypentane, 1,2-epoxyhexane, 2,3-epoxyhexane, 3,4-epoxyhexane, 3-methyl-1,2-epoxyhexane , 3-methyl-1,2-epoxyheptane, 4-methyl-1,2-epoxyheptane, 1,2-epoxyoctane, 2,3-epoxyoctane, 1,2-epoxynonane, 2,3-epoxynonane , 1,2-epoxydecane, 1,2-epoxydodecane, epoxyethylbenzene, 1-phenyl-1,2-epoxypropane, 3-phenyl-1,2-epoxypropane and the like. Examples of the monovalent epoxy compound represented by formula (V) include various alkyl glycidyl ethers. Examples of the monovalent epoxy compound represented by formula (VI) include various alkylene glycol monoglycidyl ethers. Examples of the monovalent epoxy compound represented by formula (VII) include various alkenyl glycidyl ethers. Examples of the monovalent epoxy compound represented by formula (VIII) include various epoxy alkanols such as glycidol. Examples of the monovalent epoxy compound represented by formula (IX) include various epoxycycloalkanes. Examples of the monovalent epoxy compound represented by formula (X) include various epoxycycloalkenes.

Among monovalent epoxy compounds, epoxy compounds having 2 to 8 carbon atoms are preferred. In particular, from the viewpoint of ease of handling and reactivity, the monovalent epoxy compound preferably has 2 to 6 carbon atoms, and even more preferably 2 to 4 carbon atoms. Furthermore, the monovalent epoxy compound is particularly preferably a compound represented by formula (IV) or formula (V). Specifically, from the viewpoint of reactivity with EVOH (A), processability of the obtained multilayer structure and thermoformed product, gas barrier properties, etc., 1,2-epoxybutane, 2,3-epoxybutane, epoxy Propane, epoxyethane or glycidol are preferred, with epoxypropane or glycidol being more preferred.

In the structural unit (Z), R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are preferably hydrogen atoms or aliphatic hydrocarbon groups having 1 to 5 carbon atoms, such as methyl group, ethyl group, n-propyl group, isopropyl group, Preferred are n-butyl, isobutyl, tert-butyl or n-pentyl.

The method for incorporating the structural unit (Z) into EVOH (A) is not particularly limited, and examples thereof include the method described in JP-A No. 2014-034647.

EVOH (A) may be used alone or in combination of two or more.

The lower limit of the content of EVOH (A) in the resin composition of the present invention may be, for example, 50% by mass, but preferably 70% by mass, more preferably 80% by mass, even more preferably 90% by mass, and 95% by mass. , 97% by mass or 99% by mass may be even more preferred. On the other hand, the upper limit of the content of EVOH (A) may be, for example, 99.9% by mass. Note that the content of EVOH (A) refers to the content (content ratio) in the resin composition in a dry state. Hereinafter, the same applies to the content based on the resin composition.

(Aluminum ion (B))
The aluminum ion (B) contained in the resin composition of the present invention may exist in a state dissociated from an anion, or may exist in a salt state combined with an anion. Further, it may exist in a coordinated state with a group (for example, a carboxy group, a hydroxyl group, etc.) possessed by EVOH (A) or other optional components.

The aluminum ion (B) is usually derived from a salt, but preferably derived from a fatty acid aluminum salt having 5 or less carbon atoms. That is, when preparing the resin composition of the present invention, it is preferable to use a fatty acid aluminum salt having 5 or less carbon atoms. In other words, in the resin composition of the present invention, it is preferable that a fatty acid aluminum salt having 5 or less carbon atoms is added or contained as a component constituting the aluminum ion (B). Aluminum salts of fatty acids having 5 or less carbon atoms have relatively high solubility in water. Therefore, even if a fatty acid aluminum salt having a carbon number of 5 or less is added in the manufacturing process, precipitation is unlikely to occur, and a resin composition or molded article with excellent appearance and less foreign matter can be obtained. The added fatty acid aluminum salt having 5 or less carbon atoms may be present in the resin composition in the form of a salt in which the aluminum ion (B) and the fatty acid anion remain bonded, and the aluminum ion (B) and the fatty acid anion may be present in the resin composition. The anion may be present in the resin composition in a dissociated state.

Examples of fatty acid aluminum salts having 5 or less carbon atoms include aluminum formate (aluminum triformate, etc.), aluminum acetate, aluminum propionate (aluminum tripropionate, etc.), aluminum butyrate (aluminum tributyrate, etc.), and the like. Among these, it is preferable to use at least one of aluminum acetate and aluminum tripropionate. Here, aluminum acetate is a general term for substances having the structure of aluminum salts of acetic acid, such as basic aluminum acetate and aluminum triacetate. From the viewpoint of solubility in the solvent, one or more of these may be used as appropriate.

In addition, fatty acid aluminum salts having 6 or more carbon atoms, aluminum salts other than fatty acid aluminum salts (aluminum nitrate, aluminum sulfate, etc.), etc. can also be used.

In the resin composition of the present invention, the content (b) of aluminum ions (B) per 1 g of EVOH (A), that is, the content of aluminum ions (B) based on the content (mass) of EVOH (A). The lower limit (amount of substance: number of moles) is 0.002 μmol/g, preferably 0.005 μmol/g, and more preferably 0.01 μmol/g or 0.015 μmol/g. On the other hand, the upper limit of the content (b) is 0.17 μmol/g, preferably 0.15 μmol/g, more preferably 0.10 μmol/g, and even more preferably 0.05 μmol/g or 0.03 μmol/g. In some cases it may be preferable. By setting the content (b) of aluminum ions (B) per 1 g of EVOH (A) within the above range, generation of lumps can be suppressed, heat resistance and light resistance, and resistance to formation of microplastics can be sufficiently improved. In particular, by setting this content (b) within a relatively large range, heat resistance and light resistance and resistance to forming microplastics tend to be greatly improved. On the other hand, by setting this content (b) within a relatively small range, the effect of suppressing the generation of lumps tends to be enhanced.

The ratio of the total content (i + ii) of carboxylic acid units (I) and lactone ring units (II) located at the polymer terminal of EVOH (A) and the content (b) of aluminum ions (B) ((i + ii) The lower limit of /b) is preferably 180, more preferably 300, and even more preferably 1,000. On the other hand, the upper limit of this ratio ((i+ii)/b) is preferably 20,000, more preferably 15,000, and may even more preferably be 10,000, 8,000, 6,000, or 4,000. . By setting the ratio ((i+ii)/b) within the above range, it is possible to more sufficiently improve the suppression of generation of lumps, heat resistance and light resistance, and resistance to formation of microplastics. In particular, by setting this ratio ((i+ii)/b) to a relatively high range, excess aluminum ions (B) that do not contribute to the interaction with EVOH (A) are reduced, which has the effect of suppressing the generation of lumps. is on the rise. On the other hand, by setting the ratio ((i+ii)/b) to a relatively low range, heat resistance and light resistance and resistance to forming microplastics tend to be further improved.

The lower limit of the content of aluminum ions (B) in the resin composition of the present invention may be, for example, 0.01 ppm, preferably 0.05 ppm, and more preferably 0.1 ppm. The effect of the present invention can be further enhanced by setting the content of aluminum ions (B) in the entire resin composition to the above lower limit or more. On the other hand, the upper limit of this content is preferably 4 ppm, more preferably 3 ppm, and even more preferably 2 ppm or 1 ppm. By controlling the content of aluminum ions (B) in the entire resin composition to be below the above upper limit, it is possible to suppress the generation of lumps due to excessive aluminum ions (B).
In addition, in this specification, "ppm" indicates content (content ratio) on a mass basis.

(Compound (C))
It is preferable that the resin composition of the present invention further contains compound (C). Compound (C) is at least one selected from the group consisting of cinnamic acids and conjugated polyene compounds. When the resin composition further contains such a compound (C), it is possible to further improve the suppression of generation of lumps, heat resistance and light resistance, and resistance to formation of microplastics. Although the reason for this is not clear, it is presumed that heat resistance and light resistance are improved by the aluminum ion (B) further interacting with the compound (C).

Cinnamic acids include cinnamic acid (cis-cinnamic acid, trans-cinnamic acid, or mixtures thereof) and cinnamic acid derivatives such as cinnamic acid esters and cinnamic acid salts. The cinnamic acid derivative refers to a compound etc. obtained by reacting cinnamic acid. Examples of cinnamic acid esters include methyl cinnamate, ethyl cinnamate, and the like. Examples of the cinnamate include sodium cinnamate, magnesium cinnamate, calcium cinnamate, and the like. Among these, it is preferable to use cinnamic acid as the cinnamic acid, particularly trans-cinnamic acid from the viewpoints of stability and cost. In addition, when cinnamic acid is used, part or all of the cinnamic acid may become a cinnamic acid salt due to coexistence with aluminum ions (B).

Conjugated polyene compounds have a structure in which carbon-carbon double bonds and carbon-carbon single bonds are alternately connected, and the number of carbon-carbon double bonds is 2 or more, so-called conjugated double bonds. It is a compound. This conjugated polyene compound may be a conjugated diene having two conjugated double bonds, a conjugated triene having three conjugated double bonds, or a conjugated polyene having more than that number. Moreover, the above-mentioned conjugated double bonds may not be conjugated with each other but may exist in one molecule. For example, compounds having three conjugated triene structures in the same molecule, such as tung oil, are also included in the above conjugated polyene compounds.

The number of conjugated double bonds in the conjugated polyene compound is preferably 7 or less. Coloring can be reduced by using a conjugated polyene compound having 7 or less conjugated double bonds.

In addition to conjugated double bonds, conjugated polyene compounds contain carboxy groups and their salts, hydroxyl groups, ester groups, carbonyl groups, ether groups, amino groups, imino groups, amide groups, cyano groups, diazo groups, nitro groups, and sulfone groups. and salts thereof, sulfonyl groups, sulfoxide groups, sulfide groups, thiol groups, phosphoric acid groups and salts thereof, phenyl groups, halogen atoms, double bonds, triple bonds, and other functional groups.

Examples of conjugated polyene compounds include isoprene, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-t-butyl-1,3-butadiene, and 1,3-pentadiene. , 2,3-dimethyl-1,3-pentadiene, 2,4-dimethyl-1,3-pentadiene, 3,4-dimethyl-1,3-pentadiene, 3-ethyl-1,3-pentadiene, 2-methyl -1,3-pentadiene, 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, 1,3-hexadiene, 2,4-hexadiene, 2,5-dimethyl-2,4-hexadiene , 1,3-octadiene, 1,3-cyclopentadiene, 1,3-cyclohexadiene, 1-phenyl-1,3-butadiene, 1,4-diphenyl-1,3-butadiene, 1-methoxy-1,3 -Butadiene, 2-methoxy-1,3-butadiene, 1-ethoxy-1,3-butadiene, 2-ethoxy-1,3-butadiene, 2-nitro-1,3-butadiene, chloroprene, 1-chloro-1 , 3-butadiene, 1-bromo-1,3-butadiene, 2-bromo-1,3-butadiene, ocimene, phellandrene, myrcene, farnesene, sorbic acid, sorbic acid ester, sorbate, and other conjugated diene compounds;
Conjugated triene compounds such as 1,3,5-hexatriene, 2,4,6-octatriene-1-carboxylic acid, eleostearic acid, tung oil, cholecalciferol, fulvene, tropone;
Examples include conjugated polyene compounds such as cyclooctatetraene, 2,4,6,8-decatetraene-1-carboxylic acid, retinol, and retinoic acid.

The molecular weight of the conjugated polyene compound is usually 1,000 or less, preferably 500 or less, and more preferably 300 or less. When the molecular weight of the conjugated polyene compound is 1,000 or less, the state of dispersion of the conjugated polyene compound in EVOH (A) is improved, and the appearance after melt molding is improved.

As the conjugated polyene compound, sorbic acid, sorbic acid ester, sorbate, myrcene, and mixtures of two or more of these are preferred, and sorbic acid, sorbate, and mixtures thereof are more preferred. Sorbic acid, sorbate salts, and mixtures thereof are highly effective in suppressing oxidative deterioration at high temperatures, and are also widely used industrially as food additives, so they are preferable from the viewpoint of hygiene and availability.

Compound (C) may be an unsaturated carboxylic acid or a salt thereof. Examples of such compounds include cinnamic acid, sorbic acid, and salts thereof. The number of carbon atoms in this unsaturated carboxylic acid is preferably 4 or more and 20 or less, more preferably 6 or more and 10 or less. Compound (C) may exist in the form of an anion.

In the resin composition of the present invention, the lower limit of the content (c) of the compound (C) relative to EVOH (A) is preferably 1 ppm, more preferably 5 ppm, even more preferably 10 ppm, and even more preferably 30 ppm. By setting the content (c) of the compound (C) to the above lower limit or more, the effect of containing the compound (C) can be particularly fully exhibited. On the other hand, the upper limit of this content (c) is preferably 1,000 ppm, more preferably 500 ppm, based on EVOH (A). When the content (c) of the compound (C) is below the above upper limit, the occurrence of lumps can be further reduced. The content of compound (C) in the entire resin composition of the present invention is also preferably within the above range. The above content (c) is the content (mass) of compound (C) per 1 g of EVOH (A), and the content (mass) of compound (C) with respect to the content (mass) of EVOH (A). ) is the ratio.

(Nonionic surfactant (N))
The resin composition of the present invention contains 0.1 ppm or more and 1,000 ppm or less of a nonionic surfactant (N) based on EVOH (A) as described above, so that the resin composition can be easily discharged during melt molding. The amount can be increased, and coloring of the obtained molded product can be suppressed. When the content (n) of the nonionic surfactant (N) is less than 0.1 ppm, the effect of increasing the discharge amount of the resin composition cannot be sufficiently obtained, and the effect of suppressing coloring cannot be sufficiently obtained. do not have. The content (n) is preferably 0.5 ppm or more, more preferably 1 ppm or more. On the other hand, if the above content (n) exceeds 1,000 ppm, it is not only economically disadvantageous, but also the supply of resin to the extruder becomes insufficient due to resin slippage, and the discharge amount of the above resin composition also decreases. In addition to this, the residence time of the resin composition in the extruder increases, and the resin and the resulting molded product tend to yellow. Moreover, when the content (n) exceeds 1,000 ppm, the interlayer adhesiveness of the obtained laminate tends to decrease. The content (n) is preferably 400 ppm or less, more preferably 300 ppm or less, and even more preferably 150 ppm or less.

The nonionic surfactant (N) is not particularly limited, but is preferably at least one selected from the group consisting of ether type, aminoether type, ester type, ester/ether type, and amide type. These nonionic surfactants (N) may be used alone or in combination of two or more.

(ether type nonionic surfactant)
As the ether type nonionic surfactant, polyoxyalkylene alkyl ether, polyoxyalkylene alkenyl ether, and polyoxyethylene styrenated phenyl ether are preferred.

As the polyoxyalkylene alkyl ether and polyoxyalkylene alkenyl ether, those represented by the following formula (i) are suitable.
RO-(AO) _n H...(i)

In formula (i), R is a linear or branched alkyl group or alkenyl group having 6 to 22 carbon atoms, A is each independently an alkylene group having 2 to 4 carbon atoms, and n is a polycarbonate group. It represents the degree of condensation of oxyalkylene units and ranges from 1 to 30.

In formula (i), the number of carbon atoms in R is preferably 8 to 18, more preferably 12 or more. The number of carbon atoms in A is preferably 2 or 3. n is preferably 2 to 25, more preferably 3 to 20, and even more preferably 4 or more.

Specifically, the polyoxyalkylene alkyl ether includes polyoxyethylene hexyl ether, polyoxyethylene heptyl ether, polyoxyethylene octyl ether, polyoxyethylene-2-ethylhexyl ether, polyoxyethylene nonyl ether, polyoxyethylene decyl ether, Polyoxyethylene alkyl ether such as polyoxyethylene lauryl ether, polyoxyethylene tetradecyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene icosyl ether, polyoxypropylene alkyl such as polyoxypropylene stearyl ether Examples include ether, polyoxyethylene polyoxypropylene alkyl ether, and the like.

Specific examples of the polyoxyalkylene alkenyl ether include polyoxyethylene alkenyl ethers such as polyoxyethylene oleyl ether.

Specific examples of the polyoxyethylene styrenated phenyl ether include polyoxyethylene monostyrenated phenyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene tristyrenated phenyl ether, and the like. The number of ethylene oxide added to the polyoxyethylene styrenated phenyl ether is preferably 5 to 30 moles.

(Aminoether type nonionic surfactant)
As the aminoether type nonionic surfactant, polyoxyalkylenealkylamine, polyoxyalkylenealkenylamine, etc. are preferable. Suitable examples of the polyoxyalkylene alkylamine include cocoaalkylamine-ethylene oxide adducts, polyoxyethylene stearylamine, polyoxyethylene laurylamine, polyoxyethylene polyoxypropylene laurylamine, and polyoxyethylene stearylamine. As the polyoxyalkylene alkenylamine, polyoxyethylene oleylamine and the like are suitable. The number of ethylene oxide added to the polyoxyalkylene alkylamine is preferably 1 to 40 moles.

(ester type nonionic surfactant)
Examples of ester type nonionic surfactants include polyoxyalkylene alkyl ester, polyoxyalkylene alkenyl ester, sorbitan alkyl ester, sorbitan alkenyl ester, polyoxyethylene sorbitan alkyl ester, polyoxyethylene sorbitan alkylene ester, glycerol alkyl ester, and glycerol. Preferred are alkenyl esters, polyglycerin alkyl esters, polyglycerin alkenyl esters, and the like.

As the polyoxyalkylene alkyl ester and polyoxyalkylene alkenyl ester, those represented by the following formula (ii) are preferable.
R-COO(AO) _n H...(ii)

In formula (ii), the definitions of R, A and n are the same as in formula (i) above. In formula (ii), R preferably has 8 to 18 carbon atoms, A preferably has 2 or 3 carbon atoms, and n preferably has 7 to 14 carbon atoms. When n is within the above range, both good discharge amount and good appearance can be achieved.

Specific examples of the polyoxyalkylene alkyl ester include polyoxyethylene monolaurate, polyoxyethylene dilaurate, polyoxyethylene monopalmitate, polyoxyethylene monostearate, and polyoxyethylene distearate.

Specific examples of the polyoxyalkylene alkenyl ester include polyoxyethylene oleate, polyethylene glycol dioleate, and the like.

Specifically, suitable sorbitan alkyl esters include sorbitan monocaprylate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan distearate, sorbitan tristearate, and sorbitan monolaurate.

Specifically, sorbitan alkenyl esters are preferably sorbitan monooleate, sorbitan trioleate, sorbitan sesquioleate, and the like.

Specifically, polyoxyethylene sorbitan alkyl esters include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristearate, and polyoxyethylene sorbitan triiso. Examples include stearate, polyoxyethylene sorbitan monolaurate, and the like.

Specific examples of the polyoxyethylene sorbitan alkenyl ester include polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, and the like.

Specific examples of the glycerol alkyl ester include glycerol monostearate, glycerol monomyristate, and the like.

Specific examples of the glycerol alkenyl ester include glycerol monooleate and the like.

Specific examples of the polyglycerin alkyl ester include diglycerin laurate, tetraglycerin stearate, polyglycerin laurate, and polyglycerin stearate.

Specific examples of the polyglycerin alkenyl ester include polyglycerin oleate.

(Ester/ether type nonionic surfactant)
Examples of ester/ether type nonionic surfactants include polyoxyethylene sorbitan alkyl ester, polyoxyethylene sorbitan alkenyl ester, and the like.

(amide type surfactant)
As the amide type nonionic surfactant, higher fatty acid amides are preferred, and higher fatty acid alkanolamides are more preferred.

Examples of higher fatty acid alkanolamides include higher fatty acid mono- or dialkanolamides, specifically caproic acid mono- or diethanolamide, caprylic acid mono- or diethanolamide, capric acid mono- or diethanolamide, lauric acid mono- or diethanolamide. , palmitic acid mono- or diethanolamide, stearic acid mono- or diethanolamide, oleic acid mono- or diethanolamide, coconut oil fatty acid mono- or diethanolamide, and those in which the ethanolamide constituting these is replaced by propanolamide or butanolamide, etc. Can be mentioned.

Examples of higher fatty acid amides other than higher fatty acid alkanolamide include caproic acid amide, caprylic acid amide, capric acid amide, lauric acid amide, palmitic acid amide, stearic acid amide, and oleic acid amide.

Nonionic surfactants (N) include polyoxyalkylene alkyl ether, polyoxyalkylene alkenyl ether, polyoxyethylene styrenated phenyl ether, polyoxyalkylene alkylamine, polyoxyalkylene alkenylamine, polyoxyalkylene alkyl ester, Consisting of oxyalkylene alkenyl ester, sorbitan alkyl ester, sorbitan alkenyl ester, polyoxyethylene sorbitan alkyl ester, polyoxyethylene sorbitan alkenyl ester, glycerol alkyl ester, glycerol alkenyl ester, polyglycerin alkyl ester, polyglycerin alkenyl ester and higher fatty acid amide At least one selected from the group is more preferred.

In particular, from the viewpoint of obtaining a molded product with suppressed coloring, the nonionic surfactant (N) is preferably an ether type or an ester type, and among them, from the viewpoint of coloring, polyoxyalkylene alkyl ether, polyoxyalkylene alkenyl More preferred is at least one selected from the group consisting of ether, polyoxyalkylene alkyl ester, polyoxyalkylene alkenyl ester, glycerol alkyl ester, polyglycerin alkyl ester, and polyglycerin alkenyl ester. These may be used alone or in combination.

(Other ingredients)
The resin composition of the present invention may contain other components other than EVOH (A), aluminum ion (B), compound (C), and nonionic surfactant (N) as long as the effects of the present invention are not inhibited. May contain. The content of the other components in the resin composition is preferably 0.005% by mass or more and 50% by mass or less. The content is more preferably 20% by mass or less, further preferably 10% by mass or less, particularly preferably 5% by mass or less, and most preferably 1% by mass or less. Here, when two or more types of components are used, the total content may be within the above range.

The resin composition of the present invention preferably contains at least one additive selected from the group consisting of antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, and fillers. The content of the additive in the resin composition is preferably 0.005% by mass or more and 50% by mass or less. The content is more preferably 20% by mass or less, further preferably 10% by mass or less, particularly preferably 5% by mass or less, and most preferably 1% by mass or less.

The above antioxidants include N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide], N,N'-1,6- Hexanediylbis{N-(2,2,6,6-tetramethyl-4-piperidinyl)-formamide}, 2,5-di-t-butylhydroquinone, 2,6-di2,2'-methylene-bis -(4-methyl-6-t-butylphenol), octadecyl-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate, 4,4'-thiobis-(6-t- butylphenol), etc.

Examples of the ultraviolet absorbers include ethylene-2-cyano-3,3'-diphenylacrylate, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-methyl phenyl)benzotriazole, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole, Examples include 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, and 2-hydroxy-4-oxytoxybenzophenone.

Examples of the plasticizer include dimethyl phthalate, diethyl phthalate, dioctyl phthalate, wax, liquid paraffin, and phosphate ester.

Examples of the antistatic agent include pentaerythritol monostearate, sorbitan monopalmitate, sulfated polyolefins, polyethylene oxide, polyethylene glycol (trade name: Carbowax), and the like.

Examples of the lubricant include ethylene bisstearamide, butyl stearate, and the like.

Examples of the filler include glass fiber, wollastonite, calcium silicate, talc, montmorillonite, and the like.

The resin composition of the present invention may contain a thermoplastic resin other than EVOH (A) as the other component. Thermoplastic resins include polyolefins [polyethylene, polypropylene, poly(1-butene), poly(4-methyl-1-pentene), ethylene-propylene copolymers, and copolymers of ethylene and α-olefins having 4 or more carbon atoms. Polymers, copolymers of olefin and maleic anhydride, ethylene-vinyl ester copolymers, ethylene-acrylic ester copolymers, modified polyolefins obtained by graft-modifying these with unsaturated carboxylic acids or derivatives thereof]; Examples include nylon (nylon 6, nylon 66, nylon 6/66 copolymer, etc.); polyvinyl chloride; polyvinylidene chloride; polyester; polystyrene; polyacrylonitrile; polyurethane; polyacetal; modified polyvinyl alcohol. The content of the thermoplastic resin other than EVOH (A) in the resin composition of the present invention is preferably 45% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and 5% by mass or less. Particularly preferred, and most preferably 1% by mass or less.

The resin composition of the present invention may contain compounds such as various acids as other components from the viewpoint of thermal stability and viscosity adjustment. Examples of this compound include carboxylic acids, phosphoric acid compounds, and boron compounds, and specific examples include the following. Note that these compounds may be contained in EVOH in advance.
Carboxylic acids: Oxalic acid, succinic acid, benzoic acid, citric acid, acetic acid, lactic acid, etc. Phosphoric acid compounds: Various acids such as phosphoric acid, phosphorous acid, and their salts, etc. Boron compounds: Boric acid, boric acid ester, boric acid Salt, boron hydride, etc.

(melt flow rate)
The lower limit of the melt flow rate of the resin composition of the present invention at a temperature of 210° C. and a load of 2,160 g is preferably 1.0 g/10 minutes, more preferably 2.0 g/10 minutes. On the other hand, the upper limit of this melt flow rate is preferably 30 g/10 minutes, more preferably 20 g/10 minutes, and even more preferably 10 g/10 minutes. When the melt flow rate of the resin composition of the present invention is within the above range, melt moldability, processability, etc. will be good.

(Method for manufacturing resin composition)
The method for producing the resin composition of the present invention includes producing a resin composition containing EVOH (A) and aluminum ions (B), and then mixing this resin composition with a nonionic surfactant (N). Examples include a method of mixing EVOH (A), aluminum ions (B) and a nonionic surfactant (N) all at once.

As a method for producing a resin composition containing EVOH (A) and aluminum ions (B), for example, 1) a porous precipitate of EVOH (A) with a water content of 20 to 80% by mass, containing an aluminum salt, etc. 2) A method in which EVOH (A) is made to contain an aluminum salt, etc. by contacting with an aqueous dispersion, and then dried; 2) After a homogeneous solution (water/alcohol solution, etc.) of EVOH (A) is made to contain an aluminum salt, etc. , a method of extruding it into a strand shape into a coagulation liquid, then cutting the obtained strand to form pellets, and further drying it; 3) a method of dry blending EVOH (A) and an aluminum salt etc. all at once; 4. ) EVOH (A) and aluminum salt etc. are dry blended together and then melt kneaded using an extruder etc.; 5) After obtaining the ethylene-vinyl ester copolymer during the production of EVOH (A), Examples include a method of adding an aluminum salt or the like. In order to obtain the effects of the present invention more markedly, methods 1), 2) and 5) are preferred because they provide excellent dispersibility of aluminum ions (B).

In the methods 1) and 2) above, after the aluminum salt etc. are added, and in the method 5), after the ethylene-vinyl ester copolymer is obtained, the saponification step and the washing step are performed. , usually followed by drying. As such a drying method, various drying methods can be adopted. For example, a substantially pellet-like resin composition is subjected to fluidized drying while being stirred and dispersed mechanically or with hot air, and a substantially pellet-like resin composition is subjected to dynamic actions such as stirring and dispersion. One example is drying that is performed without being applied. Examples of the dryer for fluidized drying include a cylindrical and groove type stirring dryer, a cylindrical tube dryer, a rotary dryer, a fluidized bed dryer, a vibrating fluidized bed dryer, a conical rotary dryer, and the like. As a dryer for performing stationary drying, a batch type box type dryer is used as a material stationary type, and a band dryer, tunnel dryer, vertical type dryer, etc. are listed as a material transfer type. Fluidized drying and stationary drying may be performed in combination.

Air or an inert gas (nitrogen gas, helium gas, argon gas, etc.) is used as the heating gas used during the drying process. ) is preferable in terms of suppressing thermal deterioration. The time for the drying treatment depends on the water content of the resin composition and the amount of treatment, but is usually preferably about 15 minutes to 72 hours from the viewpoint of productivity and prevention of thermal deterioration of EVOH (A).

Further, as the method 4) above, there is, for example, a method of melt-kneading using a single-screw or twin-screw extruder. The melt-kneading temperature is usually 150 to 300°C, preferably 170 to 250°C.

The resin composition containing EVOH (A) and aluminum ions (B) and the nonionic surfactant (N) can be mixed by a known method such as melt kneading.

Melt-kneading of EVOH (A), nonionic surfactant (N), etc. can be performed using a known mixing device or kneading device such as a kneader-ruder, an extruder, a mixing roll, a Banbury mixer, or the like. Examples of the nonionic surfactant (N) include solids such as powders, melts, solutions such as aqueous solutions, and dispersions such as aqueous dispersions. The nonionic surfactant (N) in this embodiment can be mixed with EVOH (A) and other components. The preferred embodiment of the nonionic surfactant (N) is a solution or a dispersion. The temperature when melting and kneading a mixture containing EVOH (A), a nonionic surfactant (N), etc. may be adjusted as appropriate depending on the melting point of the EVOH (A) used, but is usually 120°C. ~300℃.

The resin composition of the present invention is preferably manufactured by a manufacturing method that includes a step of melt-kneading a mixture containing EVOH (A), a nonionic surfactant (N), and water. The above mixture may further contain aluminum ions (B). The content of water in the above mixture is preferably 0.1 parts by mass or more and 50 parts by mass or less, and 0.5 parts by mass or more and 50 parts by mass or less, based on 100 parts by mass of EVOH (A). is more preferable. By setting the content to 0.1 part by mass or more, the resulting resin composition tends to be less likely to be colored. On the other hand, by setting the above content to 50 parts by mass or less, it is possible to suppress the tendency for foaming to occur in the resin composition discharged from the extruder due to phase separation between EVOH (A) and water. . The content of water in the above mixture means the total of water added alone and water added together with other components, and is not included in EVOH (A) or nonionic surfactant (N) due to moisture absorption etc. It also includes water. Methods of adding water together with other components include methods of using an aqueous solution or dispersion as a nonionic surfactant (N), and methods of adding water as EVOH (A) containing a predetermined amount of water, as described below. Examples of methods used include:

In the above production method, an aqueous solution or aqueous dispersion containing a nonionic surfactant (N) is added to EVOH (A) or a resin composition containing EVOH (A) and aluminum ions (B) to obtain the above mixture. It is preferable. By adding the nonionic surfactant (N) as an aqueous solution or dispersion, the nonionic surfactant (N) becomes easier to disperse in the EVOH (A).

In the above manufacturing method, an aqueous solution or aqueous dispersion containing a nonionic surfactant (N) is added to EVOH (A) or a resin composition containing EVOH (A) and aluminum ions (B) before melting. Alternatively, an aqueous solution or aqueous dispersion containing a nonionic surfactant (N) may be added to the molten EVOH (A) or a composition containing EVOH (A) and aluminum ions (B). The latter is preferred from the viewpoint of productivity.

A method for melt-kneading a mixture containing EVOH (A), a nonionic surfactant (N), and water includes, for example, extruding EVOH (A) or a resin composition containing EVOH (A) and aluminum ions (B). An example of a method is to add a nonionic surfactant (N) and other components as necessary to the molten EVOH (A) after introducing it into a machine, knead it, and then discharge it. At this time, EVOH (A) or a resin composition containing EVOH (A) and aluminum ions (B) having a water content of 5 to 40% by mass may be introduced into the extruder.

The resin composition of the present invention can be processed into any form such as pellets or powder and used as a molding material, and is usually in a dry state. The upper limit of the water content relative to the total solid content of the resin composition of the present invention may be preferably 1% by mass, and more preferably 0.1% by mass or 0.01% by mass. When the resin composition of the present invention is in a dry state, it can exhibit good melt moldability and the like.

<Molded object>
The resin composition of the present invention can be molded into molded objects such as films, sheets, tubes, bags, containers, etc. by melt molding or the like. That is, the molded article of the present invention is a molded article molded from the resin composition of the present invention. The molded article of the present invention may be formed only from the resin composition of the present invention, or may have portions formed from other materials. For example, a laminate (multilayer structure), which will be described later, is also a form of molded product.

The molded product of the present invention suppresses the occurrence of lumps during melt molding, has sufficient heat and light resistance, and is difficult to turn into microplastic after disposal, and has sufficient characteristics as described above compared to products using the same EVOH. has been improved. Moreover, the molded article of the present invention has suppressed discoloration and has a good appearance. Furthermore, in order to obtain a constant discharge rate, the temperatures of the supply section/compression section/measuring section/die are usually adjusted to 175°C/200°C/210°C/210°C in order to compress the composition containing EVOH. However, by using the resin composition of the present invention, the temperature of the feeding section and the compression section is set to a relatively high temperature, which is lower than the normal temperature by 10 degrees Celsius or more. Even under certain conditions, a constant discharge amount can be obtained. Therefore, the resin composition of the present invention is particularly useful as a melt molding material.

Examples of methods for melt molding the resin composition of the present invention include extrusion molding, cast molding, inflation extrusion molding, blow molding, melt spinning, injection molding, and injection blow molding. The melt molding temperature varies depending on the melting point of EVOH (A), etc., but is preferably about 150 to 270°C. These molded bodies can also be crushed and molded again for the purpose of reuse. It is also possible to uniaxially or biaxially stretch films, sheets, etc.

<Laminated body (multilayer structure)>
The laminate of the present invention has at least one layer made of the resin composition of the present invention. The laminate usually has a layer made of the resin composition of the present invention and a layer made of other components. The lower limit of the number of layers in the laminate of the present invention is, for example, 2, may be 3, or may be 4. The upper limit of this number of layers is, for example, 1,000, which may be 100, or may be 20.

Examples of the layer made of other components include layers made of thermoplastic resin other than EVOH (A), paper, woven fabric, nonwoven fabric, metal cotton strip, wood surface, metal, etc. A thermoplastic resin layer is preferred. The layer structure of the laminate of the present invention is not particularly limited, and when a layer made of the resin composition of the present invention is represented by E, an adhesive layer is represented by Ad, and a layer obtained from another thermoplastic resin is represented by T, T/E/ Examples include structures such as T, E/Ad/T, and T/Ad/E/Ad/T. Each of these layers may be a single layer or a multilayer.

The method for producing the laminate of the present invention is not particularly limited, and examples include a method of melt-extruding a thermoplastic resin into a molded article (film, sheet, etc.) obtained from the resin composition of the present invention, A method of co-extruding the resin composition of the present invention with another thermoplastic resin, a method of co-injecting the resin composition of the present invention with another thermoplastic resin, and a method of co-injecting the resin composition of the present invention with another thermoplastic resin layer. Examples include a method of laminating using a known adhesive such as an isocyanate compound or a polyester compound.

Other thermoplastic resins mentioned above include linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, polypropylene, propylene-α- Olefin (α-olefin having 4 to 20 carbon atoms) copolymers, olefins alone or copolymers thereof such as polybutene and polypentene; polyester polyester elastomers such as polyethylene terephthalate, polyamides such as nylon-6 and nylon-66, polystyrene , polyvinyl chloride, polyvinylidene chloride, acrylic resin, vinyl ester resin, polyurethane elastomer, polycarbonate, chlorinated polyethylene, chlorinated polypropylene, and the like. Among them, polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, polyamide, polystyrene and polyester are preferably used.

The adhesive layer needs only to have adhesive properties with the layer of the resin composition of the present invention and the layer of other thermoplastic resin, and an adhesive resin containing a carboxylic acid-modified polyolefin is preferable. As the carboxylic acid-modified polyolefin, a modified olefin-based polymer containing a carboxyl group obtained by chemically bonding an ethylenically unsaturated carboxylic acid, its ester, or its anhydride to an olefin-based polymer is suitably used. Here, the olefin polymer refers to polyolefins such as polyethylene, linear low-density polyethylene, polypropylene, and polybutene, and copolymers of olefins and other monomers. Among these, linear low-density polyethylene, ethylene-vinyl acetate copolymer, and ethylene-acrylic acid ethyl ester copolymer are preferred, and linear low-density polyethylene and ethylene-vinyl acetate copolymer are particularly preferred.

When the laminate of the present invention is a multilayer film or sheet, the average thickness is not particularly limited, and the lower limit may be, for example, 1 μm, 5 μm, or 10 μm. On the other hand, the upper limit of the average thickness may be, for example, 3 mm, 1 mm, 300 μm, or 100 μm. The shape of the laminate is not particularly limited as long as it has a laminate structure. A multilayer thermoformed container, a multilayer blow molded container, a multilayer pipe, a vapor deposited film, etc., which will be described later, are also included in the form of the laminate.

The molded bodies and laminates of the present invention suppress the occurrence of lumps during melt molding, have sufficient heat and light resistance, are difficult to turn into microplastics after disposal, and have the above-mentioned properties compared to those using the same EVOH. The characteristics have been sufficiently improved. Furthermore, since the discharge amount during melt molding is large, productivity is excellent, resulting in molded products and laminates with suppressed coloring. Therefore, it is suitable for daily necessities, packaging materials, machine parts, etc. used outdoors. Examples of applications in which the characteristics of the above-mentioned molded products are especially effective include packaging materials for food and beverages, packing materials for containers, films, agricultural films, geomembranes, medical infusion bag materials, high-pressure tank materials, Gasoline tank materials, fuel containers, tire tube materials, shoe cushioning materials, inner bag materials for bag-in-boxes, organic liquid storage tank materials, pipes (pipe materials for transporting organic liquids, hot water pipe materials for heating (for floor heating) (hot water pipe materials, etc.), resin wallpaper, plant culture medium, etc. In particular, the molded bodies and laminates of the present invention are suitably used as films, pipes, agricultural films, plant culture media, and geomembranes that are used outdoors and are susceptible to deterioration due to heat or light.

EXAMPLES Hereinafter, the present invention will be specifically explained using Examples, but the present invention is not limited to these Examples. The methods of measurement, calculation, and evaluation were as follows.

<Measurement conditions for quantitative determination of the primary structure of EVOH (NMR method)>
Device name: JEOL superconducting nuclear magnetic resonance device ECZ-600
Observation frequency: 600MHz (1H)
(1) Solvent: heavy dimethyl sulfoxide (DMSO-d ₆ ) Polymer concentration: 5% by mass Measurement temperature: 25°C, 80°C
Flip angle: 30° Accumulation count: 256s
Internal standard substance: Tetramethylsilane (TMS)
(2) Solvent: heavy water (D ₂ O) + heavy methanol (MeOD) (mass ratio 4/6) Polymer concentration: 5% by mass Measurement temperature: 80°C
Flip angle: 30° Accumulation count: 1024s
Internal standard substance: Tetramethylsilane (TMS)

<Determination of ethylene unit content, saponification degree, terminal carboxylic acid unit content, and terminal lactone ring unit content>
The ethylene unit content (Et Cont.), saponification degree (SP), terminal carboxylic acid unit content (α), and terminal lactone ring unit content (β) of EVOH were determined by ¹ H-NMR measurement (DMSO-d ₆ solvent). : measurement results at 25°C and 80°C, measurement results with D ₂ O + MeOD solvent). Note that the chemical shift value was based on the TMS peak of 0 ppm. Moreover, in the formula, VAc, VAl and Et represent a vinyl acetate unit, a vinyl alcohol unit and an ethylene unit, respectively.
I1, I3: 0.4 to 2.35 ppm methylene hydrogen integral value (I1: DMSO-d ₆ measured value at 25°C, I3: DMSO-d ₆ measured value at 80°C)
I9:: Integral value of methylene hydrogen from 0.4 to 2.8 ppm (measured value in D ₂ O + MeOD solvent)
I2: Integral value of methine hydrogen in vinyl alcohol unit (methine hydrogen on both sides of the same unit is vinyl alcohol) of 3.4 to 4.0 ppm (DMSO-d ₆ measured value at 25°C)
I4: 3.15 to 3.45 ppm integral value of methine hydrogen in vinyl alcohol unit (methine hydrogen on both sides of the same unit is vinyl alcohol) (DMSO-d ₆ measured value at 80°C)
I5: Integral value derived from hydrogen of terminal methyl group in vinyl acetate unit (DMSO-d ₆ measured value at 80°C)
I6: Integral value around 1.8 to 1.85 (DMSO-d ₆ measured value at 80°C)
I7: Integral value derived from the hydrogen of the methyl group in the -CH(OH)CH ₃ group present at the polymer terminal of EVOH (DMSO-d ₆ measured value at 80°C)
I8: Integral value derived from the hydrogen of the methyl group in the -CH ₂ CH ₃ group present at the polymer end of EVOH (DMSO-d ₆ measured value at 80°C)
I10: Integral value around 0.8 to 0.95 (measured value with D ₂ O + MeOD solvent)
I11: Integral value derived from the hydrogen of the CH ₂ unit adjacent to the carbonyl group of the terminal lactone ring unit (measured value in D ₂ O + MeOD solvent)
I12: Integral value derived from the linear COOH group of the terminal carboxylic acid unit (measured value in D ₂ O + MeOD solvent)
I13, I14: Integral value derived from carboxylate of terminal carboxylic acid unit (measured value in D ₂ O + MeOD solvent)
Note that the determined ethylene unit content (Et Cont.), terminal carboxylic acid unit content (α), and terminal lactone ring unit content (β) are the total amount of ethylene units, vinyl ester units, and vinyl alcohol units. It is the percentage (mol%) of the amount (mol) of each unit relative to (mol). However, the content of units other than ethylene units, vinyl ester units, and vinyl alcohol units is extremely small compared to these units. Therefore, the determined ethylene unit content (Et Cont.), terminal carboxylic acid unit content (α), and terminal lactone ring unit content (β) are all based on the amount of each unit relative to the total amount (mol) of all structural units. It is substantially equal to the percentage (mol%) of the amount (mol).

<Measurement of melt flow rate (MFR)>
The dried resin composition pellets obtained in each reference example and reference comparative example were filled into a cylinder with an inner diameter of 9.55 mm and a length of 162 mm of Melt Indexer L244 (manufactured by Takara Kogyo Co., Ltd.), and after melting at 210 ° C. A load was evenly applied to the molten resin composition using a plunger having a mass of 2,160 g and a diameter of 9.48 mm. The amount of resin composition extruded per unit time (g/10 minutes) from an orifice with a diameter of 2.1 mm provided at the center of the cylinder was measured, and this was defined as MFR.

<Sodium ion content, phosphoric acid content and boric acid content>
0.5 g of the dried resin composition pellets obtained in each reference example and reference comparative example were placed in a Teflon (registered trademark) pressure vessel, and 5 mL of concentrated nitric acid was added thereto to decompose at room temperature for 30 minutes. After 30 minutes, the lid was closed, and the mixture was decomposed by heating at 150° C. for 10 minutes, then at 180° C. for 5 minutes using a wet decomposition device (“MWS-2” manufactured by Actac Co., Ltd.), and then cooled to room temperature. This treated solution was transferred to a 50 mL volumetric flask (manufactured by TPX (registered trademark)) and diluted with pure water. This solution was analyzed for metal content using an ICP emission spectrometer (PerkinElmer's "OPTIMA4300DV"), and the content of sodium ions (sodium element) and phosphoric acid was determined as a phosphate radical equivalent value, and the content of boric acid was The amount was calculated as a boron element equivalent value. For quantitative determination, calibration curves prepared using commercially available standard solutions were used.

<Acetic acid content>
20 g of the dried resin composition pellets obtained in each reference example and reference comparative example were poured into 100 ml of ion-exchanged water, and extracted by heating at 95° C. for 6 hours. Using phenolphthalein as an indicator, the extract was neutralized and titrated with 1/50 normal NaOH to quantify the acetic acid content.

<Sorbic acid content>
The dry resin composition pellets obtained in each Reference Example and Reference Comparative Example were freeze-pulverized, and coarse particles were removed using a sieve with a nominal size of 0.150 mm (100 mesh) (compliant with JIS standard Z8801-1 to 3). 22 g of the pulverized material was filled into a Soxhlet extractor, and extracted with 100 mL of chloroform for 16 hours. The amount of sorbic acid in the obtained chloroform extract was quantitatively analyzed by high performance liquid chromatography to determine the content of sorbic acid in the resin composition. In addition, for the quantitative determination, a calibration curve prepared using a standard sample of sorbic acid was used.

<Cinnamic acids content>
The dry resin composition pellets obtained in each Reference Example and Reference Comparative Example were freeze-pulverized, and coarse particles were removed using a sieve with a nominal size of 0.150 mm (100 mesh) (compliant with JIS standard Z8801-1 to 3). 22 g of the pulverized material was filled into a Soxhlet extractor, and extracted with 100 mL of acetone for 16 hours. The amount of cinnamic acid in the obtained acetone extract was quantitatively analyzed by high performance liquid chromatography to determine the content of cinnamic acid in the resin composition. In addition, for quantitative determination, a calibration curve prepared using a standard sample of cinnamic acid was used.

<Aluminum ion content>
15 g of the dry resin composition pellets obtained in each reference example and reference comparative example were weighed into a platinum crucible, and dry decomposition was performed using nitric acid and sulfuric acid. 2 mL of hydrochloric acid was added to the incinerated sample, the volume was fixed in a 50 mL volumetric flask made of polytetrafluoroethylene (PTFE), and the mixture was filtered through a PTFE filter with a pore size of 0.45 μm to prepare a sample solution. Using the solution, the aluminum ion content in the resin composition was measured by high frequency plasma emission spectrometry (ICP emission spectrometer "IRIS AP" manufactured by Jarrell Ash).

<Synthesis Example 1> Synthesis of EVOH-A Vinyl acetate (hereinafter sometimes referred to as VAc) was placed in a 200 L pressurized reaction tank equipped with a jacket, a stirrer, a nitrogen inlet, an ethylene inlet, and an initiator addition port. 75.0 kg and 7.2 kg of methanol (hereinafter sometimes referred to as MeOH) were charged, and the inside of the reaction tank was purged with nitrogen by bubbling nitrogen for 30 minutes. Next, after adjusting the temperature in the reaction tank to 65°C, ethylene was introduced so that the pressure in the reaction tank (ethylene pressure) was 4.13 MPa, and 9.4 g of 2,2'-azobis(2 ,4-dimethylvaleronitrile) (“V-65” manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) was added to initiate polymerization. During the polymerization, the ethylene pressure was maintained at 4.13 MPa and the polymerization temperature was maintained at 65°C. After 4 hours, when the conversion rate of VAc (polymerization rate based on VAc) reached 49.7%, it was cooled and a solution of 0.2 g of copper acetate dissolved in 20 kg of methanol was put into the container to start polymerization. It stopped. After the reaction tank was opened to remove ethylene, nitrogen gas was bubbled to completely remove ethylene. The polymerization solution was then withdrawn from the vessel and diluted with 20 L of MeOH. This liquid is fed from the top of the tower-shaped container, and MeOH vapor is fed from the bottom of the tower to remove unreacted monomers remaining in the polymerization liquid together with the MeOH vapor, resulting in ethylene-vinyl acetate copolymer (hereinafter referred to as A MeOH solution of (sometimes referred to as EVAc) was obtained.
Next, 150 kg of a 20% by mass MeOH solution of EVAc was charged into a 300 L reaction tank equipped with a jacket, a stirrer, a nitrogen inlet, a reflux condenser, and a solution addition port. This solution was heated to 60° C. while blowing nitrogen gas, and a MeOH solution having a sodium hydroxide concentration of 2N was added at a rate of 450 mL/min for 2 hours. After completing the addition of the sodium hydroxide MeOH solution, the temperature inside the system was kept at 60°C and the saponification reaction was carried out by stirring for 2 hours while flowing MeOH and methyl acetate produced in the saponification reaction out of the reaction tank. I let it progress. Thereafter, 8.7 kg of acetic acid was added to stop the saponification reaction.
Thereafter, 120 L of ion-exchanged water was added while heating and stirring at 80° C., MeOH was flowed out of the reaction tank, and EVOH was precipitated. The precipitated EVOH was collected by decantation and pulverized using a pulverizer. The obtained EVOH powder was poured into a 1 g/L acetic acid aqueous solution (bath ratio 20: ratio of 20 L of aqueous solution to 1 kg of powder) and washed with stirring for 2 hours. This was deliquified and further poured into a 1 g/L aqueous acetic acid solution (bath ratio 20) and washed with stirring for 2 hours. The deliquified product was poured into ion-exchanged water (bath ratio 20), stirred and washed for 2 hours, and deliquified three times for purification. The electrical conductivity of the cleaning solution was 3 μS/cm (measured with “CM-30ET” manufactured by Toa Denpa Kogyo Co., Ltd.). Next, it was immersed in 250 L of an aqueous solution containing 0.5 g/L of acetic acid and 0.1 g/L of sodium acetate with stirring for 4 hours, and then the liquid was removed, and this was dried at 60°C for 16 hours to obtain a crude dried product of EVOH. I gained 16.1 kg. The above operation was repeated to obtain 15.9 kg of a crude dried EVOH product, thereby obtaining a total of 32.0 kg of a crude dried EVOH (EVOH-A).

<Preparation of resin composition>
[Reference Examples 1 to 6 and Reference Comparative Examples 1 to 3]
A 60 L stirring tank equipped with a jacket, a stirrer, and a reflux condenser was charged with 2 kg of the crude dried EVOH (EVOH-A) obtained in Synthesis Example 1, 0.8 kg of water, and 2.2 kg of MeOH, and the mixture was heated at 60°C for 5 hours. Stir to completely dissolve. Aluminum acetate was added to the obtained solution, and the mixture was further stirred for 1 hour to completely dissolve the aluminum acetate, thereby obtaining a resin composition solution. In addition, in Reference Comparative Example 3, a resin composition solution was obtained without adding aluminum acetate. This solution is extruded through a metal plate with a diameter of 4 mm into a mixed solution of water/MeOH = 90/10 cooled to -5°C to precipitate it in the form of a strand, and the strand is cut into pellets with a strand cutter. A hydrous pellet was obtained. The water content of the obtained EVOH water-containing pellets was measured with a halogen moisture meter "HR73" manufactured by Mettler, and was found to be 52% by mass. The obtained EVOH water-containing pellets were poured into a 1 g/L acetic acid aqueous solution (bath ratio 20) and washed with stirring for 2 hours. This was deliquified and further poured into a 1 g/L aqueous acetic acid solution (bath ratio 20) and washed with stirring for 2 hours. After removing the liquid, the acetic acid aqueous solution was renewed and the same operation was performed. After washing with an acetic acid aqueous solution and deliquifying it, we poured it into ion-exchanged water (bath ratio 20), washed it with stirring for 2 hours, and deliquified it three times, until the electrical conductivity of the washing liquid was 3 μS/ cm (measured with "CM-30ET" manufactured by Toa Denpa Kogyo Co., Ltd.) and purified to obtain water-containing EVOH pellets from which the catalyst residue from the saponification reaction was removed.
The water-containing pellets were placed in an aqueous solution (bath ratio 20) with a sodium acetate concentration of 0.510 g/L, an acetic acid concentration of 0.8 g/L, and a phosphoric acid concentration of 0.04 g/L, and stirred regularly for 4 hours. It was immersed and chemically treated. The pellets were deliquified and dried at 80°C for 3 hours and at 105°C for 16 hours under a nitrogen stream with an oxygen concentration of 1% by volume or less to remove EVOH-A, acetic acid, sodium ions (sodium salts), phosphoric acid, and Dry cylindrical resin composition pellets containing aluminum ions (aluminum salt) and having an average diameter of 2.8 mm and an average length of 3.2 mm were obtained. In each reference example and reference comparative example, the aluminum ion content was adjusted as shown in Table 3 by adjusting the amount of aluminum acetate added. Ethylene content, saponification degree, terminal lactone ring unit content, terminal carboxylic acid unit content, total content of terminal carboxylic acid units and terminal lactone ring units of EVOH-A in the obtained dry resin composition pellets, The lactone ring unit ratio, MFR, and boric acid content were determined using the above quantitative method using a dry resin composition pellet having an aluminum ion content of 0.3 ppm as a sample (the same applies hereinafter). Table 2 shows the ethylene content, degree of saponification, content of terminal lactone ring units, content of terminal carboxylic acid units, total content of terminal carboxylic acid units and terminal lactone ring units, lactone ring unit ratio, MFR and boric acid content. Shown below. In addition, in all dried resin composition pellets, the sodium ion content was 90 to 110 ppm, the phosphoric acid content was 35 to 45 ppm in terms of phosphate radical, and the acetic acid content was 190 to 210 ppm. Further, FIG. 1 shows the ¹ H-NMR spectrum of EVOH-A measured under the conditions of a solvent DMSO-d ₆ and a measurement temperature of 25°C. FIG. 2 shows the ¹ H-NMR spectrum of EVOH-A measured under the conditions of a solvent DMSO-d ₆ and a measurement temperature of 80°C. FIG. 3 shows the ¹ H-NMR spectrum of EVOH-A measured under the conditions of solvent D ₂ O+MeOD and measurement temperature: 80°C.

<Synthesis Examples 2 to 11>
The amounts of raw materials used for polymerization of EVOH, the polymerization conditions, the amount charged in saponification treatment, and the addition rate of 2N sodium hydroxide MeOH solution were as shown in Table 1, and the synthesis was performed only once. In the same manner as in Example 1, 10.1 to 11.5 kg of crude dry matter of each EVOH (EVOH-B to EVOH-K) was obtained.

<Preparation of resin composition>
[Reference Examples 7 to 27, 34 and Reference Comparative Examples 4 to 23]
Reference Example except that the crude dried products of each EVOH (EVOH-B to EVOH-K) obtained in Synthesis Examples 2 to 11 above were used, and each component contained in the aqueous solution in the chemical treatment was as shown in Table 1. Each dried resin composition pellet was obtained in the same manner as in Example 1. Further, as in Reference Example 1, the aluminum ion content was adjusted as shown in Tables 3 to 12 and 14 by adjusting the amount of aluminum acetate added. Various measurements were also carried out in the same manner as in Reference Example 1 using the above quantitative method. Table 2 shows the ethylene content, degree of saponification, content of terminal lactone ring units, content of terminal carboxylic acid units, total content of terminal carboxylic acid units and terminal lactone ring units, lactone ring unit ratio, MFR and boric acid content. Shown below. In addition, the sodium ion content of all dried resin composition pellets was 90 to 110 ppm, the phosphoric acid content was 35 to 45 ppm in terms of phosphate radical, and the acetic acid content was 190 to 210 ppm.

<Preparation of resin composition>
[Reference Examples 28 to 33 and Reference Comparative Example 24]
2 kg of crudely dried EVOH (EVOH-A) obtained in Synthesis Example 1 above, 0.8 kg of water, and 2.2 kg of MeOH were charged and stirred at 60° C. for 5 hours to completely dissolve. Aluminum acetate, sorbic acid, or cinnamic acid was added to the resulting solution, and the mixture was further stirred for 1 hour to completely dissolve aluminum acetate and sorbic acid or cinnamic acid, thereby obtaining a resin composition solution. In addition, in Reference Comparative Example 24, a resin composition solution was obtained by adding only sorbic acid without adding aluminum acetate. The subsequent treatments were carried out in the same manner as in Reference Example 1 to obtain each dried resin composition pellet. The aluminum ion content was adjusted by adjusting the amount of aluminum acetate added, and the content of sorbic acid or cinnamic acid was adjusted by adjusting the amount of these additions to obtain dry resin composition pellets as shown in Table 13. Ta. Various measurements were also carried out in the same manner as in Reference Example 1 using the above quantitative method. In all dried resin composition pellets, the sodium ion content was 90 to 110 ppm, the phosphoric acid content was 35 to 45 ppm in terms of phosphate radical, and the acetic acid content was 190 to 210 ppm.

In addition, in Tables 3 to 14, the total content (mol%) of terminal carboxylic acid units and lactone ring units with respect to the total amount of ethylene units, vinyl alcohol units, and vinyl acetate units in EVOH is shown, as well as the total content (mol%) of EVOH per gram of EVOH. The total content (μmol/g) of terminal carboxylic acid units and terminal lactone ring units per unit is also shown. In addition to the aluminum ion content (ppm) in the resin composition, the aluminum ion content (μmol/g) per 1 g of EVOH is also shown. Furthermore, the ratio ((i+ii)/b ) are also shown.

<Preparation of surfactant-containing resin composition>
[Example 1]
Resin composition pellets containing EVOH-A obtained in Reference Example 2, and polyoxyethylene (7) stearyl ether as the nonionic surfactant (N) (parentheses in the compound name of the nonionic surfactant (N)) An aqueous dispersion (nonionic surfactant content: 10.0 g/L) in which the numbers in the box represent the degree of condensation of polyoxyethylene units (the same applies hereinafter) was prepared. 100 parts by mass of the resin composition pellets and 1 part by mass of the aqueous dispersion were blended. The resulting mixture was melt-kneaded under the following conditions, then pelletized and further dried to obtain resin composition pellets.
Equipment: 25mmφ twin screw extruder (“Laboplast Mill 4C150” manufactured by Toyo Seiki Seisakusho)
L/D: 25
Screw: Fully meshing type in the same direction Number of die holes: 2 holes (3mmφ)
Extrusion temperature: C1 = 200°C, C2 to C5 = 220°C, die = 220°C
Drying: Vacuum drying 90℃/20hr

(2) Quantification of nonionic surfactant After dissolving 10 g of the obtained resin composition pellets in 1,1,1,3,3,3-hexafluoro-2-propanol, the solution was added dropwise to methanol. This liquid was filtered to remove precipitates, and then concentrated. The content of the nonionic surfactant (N) in the resin composition pellets was calculated by measuring the obtained concentrate using "UPLC H-Class" manufactured by Waters. For quantitative determination, a calibration curve created using each nonionic surfactant was used. The measured contents are shown in Table 15.

[Examples 2 to 10 and Comparative Examples 1 to 4]
Using the resin composition pellets containing EVOH-A, EVOH-E, or EVOH-F obtained in Reference Examples 2, 17, and 20 and Reference Comparative Examples 1 and 2, as shown in Table 15, EVOH (A) Pellets of the resin composition were prepared in the same manner as in Example 1, except that the type of the nonionic surfactant (N) and the type and content of the nonionic surfactant (N) were changed. In all cases, a commercially available nonionic surfactant (N) was used. In addition, in Comparative Example 3, melt-kneading was performed again without blending the nonionic surfactant (N) to obtain resin composition pellets.

<Evaluation>
<Single layer film production conditions>
Each resin composition pellet obtained in Reference Examples 1 to 34, Reference Comparative Examples 1 to 24, Examples 1 to 10, and Comparative Examples 1 to 4 was formed into a film under the following conditions to obtain a single layer film with a thickness of 20 μm. Ta.
・Equipment: 20mmφ single screw extruder (D2020, manufactured by Toyo Seiki Seisakusho Co., Ltd.)
・L/D: 20
・Screw: Full flight ・Dice width: 30cm
・Take-up roll temperature: 80℃
・Screw rotation speed: 40 rpm
・Take-up roll speed: 3.0 to 3.5 m/min ・Set temperature: C1/C2/C3/D=180℃/210℃/210℃/210℃

<Suppression of the occurrence of bumps (spots)>
Fifty hours after the start of operation, the number of gel-like lumps (visible to the naked eye of 150 μm or more) in the single-layer film produced was counted and calculated per 1.0 m ² . Judgment was made as follows based on the number of particles per 1.0 ^m2 . The evaluation results are shown in Tables 3 to 14 and 16.
A: Less than 20 pieces B: 20 pieces or more and less than 40 pieces C: 40 pieces or more and less than 100 pieces D: 100 pieces or more If the evaluation result is between A and B, the occurrence of bumps has been sufficiently suppressed and no problem will occur. level. Even when the evaluation result is C, the occurrence of spots is suppressed, and although spots may become a problem depending on the application, it is at a usable level. If the evaluation result is D, there are a large number of particles and it is at an unusable level.

<Heat and light resistance test>
The obtained single-layer film was cut to a size of 150 mm in the TD direction and 70 mm in the MD direction, pasted on a PTFE sheet of the same size and 0.3 mm thick, and set in a sample holder with an opening of 135 mm width and 55 mm height. did. Using a super xenon weather meter SX75 manufactured by Suga Test Instruments Co., Ltd., ultraviolet rays were continuously irradiated for 48 hours under the conditions of irradiance of 150 W/m ² , black panel temperature of 83° C., and chamber humidity of 50% RH. After the irradiation, the unirradiated portion around the film was cut off to obtain a film sample with a width of 135 mm and a height of 55 mm for the heat and light resistance test.

<Elongation at break>
The obtained single-layer film was cut into a film sample having a size of 150 mm in the TD direction and 70 mm in the MD direction. Cuts were made in advance at 15 mm intervals with a razor blade, and the film sample was irradiated with ultraviolet rays in the same manner as in the above heat and light resistance test. The sample after irradiation with ultraviolet rays was cut into 15 mm width and 50 mm length to prepare a sample for a tensile test, and the sample was conditioned for 5 days at a temperature of 23° C. and a humidity of 50% RH. After humidity conditioning, the sample was subjected to a tensile test in the MD direction using a tensile tester (“AUTOGRAPH AGS-H” manufactured by Shimadzu Corporation) at a distance between chucks of 30 mm and a tensile speed of 500 mm/min with N=5 to determine the elongation at break. Measured (evaluation after heat and light resistance test). Furthermore, the elongation at break was similarly measured for film samples that were not irradiated with ultraviolet rays (evaluation before heat and light resistance test). The reduction rate (%) of the elongation at break after the heat and light resistance test relative to the elongation at break before the heat and light resistance test was calculated. These evaluation results are shown in Tables 3 to 14 and 16. It was determined that the lower the elongation reduction rate at break, the better the heat resistance and light resistance.

<Mass loss: accelerated microplasticization test>
Heat and light resistance test Four processed film samples were prepared and vacuum dried at 60°C for 24 hours, and then the total dry mass (W1) of the four film samples before the pulverization process described below was measured. Four film samples after the heat and light resistance test, 500 g of zirconia balls each having a diameter of 3 mm, and 100 mL of deionized water were charged into an alumina ceramic pot mill having a capacity of 300 mL. The hermetically sealed pot mill was installed on a tabletop pot mill stand "PM-001" manufactured by As One Co., Ltd., and was operated at a rotation speed of 200 rpm to carry out the pulverization treatment at room temperature for 4 hours. The contents of the pulverized pot mill were taken out along with water, and deionized water was added thereto, followed by stirring and decantation, which were repeated to separate the zirconia balls from the pulverized material and water. The contents from which the zirconia balls were removed were filtered under reduced pressure through a 46 μm nylon mesh, and the filtrate was vacuum dried at 60°C. The mass (W2) of the crushed material of 46 μm or more that remained after filtering through the nylon mesh was measured, and the mass loss (M) was calculated according to the following formula (x) (evaluation after heat and light resistance test).
M (%)=(W1-W2)/W1×100...(x)
In addition, mass loss was similarly measured for film samples that were not subjected to the ultraviolet irradiation test (evaluation before heat and light resistance test). These evaluation results are shown in Tables 3 to 14 and 16.
The value of mass loss in the evaluation after the heat and light resistance test is used as an index of microplasticization, and the smaller the value, the more suppressed microplasticization can be.

<Discharge amount evaluation test>
Each resin composition pellet obtained in Examples 1 to 10 and Comparative Examples 1 to 4 was formed into a film under the following conditions to obtain a single layer film with a thickness of 20 μm. The production amount of the single layer film per hour at this time was evaluated as the discharge amount of the resin composition. It is practical if the discharge rate is 0.5 kg/hr or more. The results are shown in Table 16.
・Equipment: 20mmφ single screw extruder (D2020, manufactured by Toyo Seiki Seisakusho Co., Ltd.)
・L/D: 20
・Screw: Full flight ・Dice width: 30cm
・Take-up roll temperature: 80℃
・Screw rotation speed: 40 rpm
・Set temperature: C1/C2/C3/D=160℃/180℃/210℃/210℃

<Single layer film coloring (appearance) evaluation>
The single-layer film produced in the above discharge rate evaluation test was wound up into a paper tube, and the coloring of the end surface of the film was evaluated with the naked eye according to the following criteria. The results are shown in Table 16. If it was A to C, it was judged that a molded article with suppressed coloring was obtained.
A: No coloration was observed. B: Slight yellowing. C: Yellowing, but to the extent that it could be put to practical use. D: Severe yellowing, making it impossible to put it into practical use.

<Evaluation of adhesion of laminate>
Each resin composition pellet obtained in Examples 1 to 10 and Comparative Examples 1 to 4, linear low-density polyethylene (LLDPE: Ultzex 2022L manufactured by Mitsui Chemicals) and adhesive resin (manufactured by SUMICA. ATOCHEM Co. Ltd.) Bondine TX8030 (hereinafter sometimes abbreviated as Ad) was used to produce a multilayer film of three types and five layers (LLDPE/Ad/resin composition/Ad/LLDPE=50 μm/10 μm/10 μm/10 μm/50 μm) as follows. I got it. Immediately after forming the multilayer film, the obtained multilayer film (laminate) was cut out to a length of 150 mm in the MD direction and 10 mm in the TD direction, and the resin composition was immediately removed using an autograph (DCS-50M manufactured by Shimadzu Corporation) in T-peel mode. The peel strength between the material layer and the Ad layer was measured and evaluated based on the following criteria. The results are shown in Table 16.
<Multilayer film forming conditions>
Extruder:
For EVOH: 20mmφ extruder Lab machine ME type CO-EXT (manufactured by Toyo Seiki Co., Ltd.)
For Ad: 25mmφ extruder P25-18AC (manufactured by Osaka Seiki Co., Ltd.)
For LLDPE: 32mmφ extruder GF-32-A (manufactured by Plastic Engineering Research Institute)
EVOH setting temperature: C1/C2/C3/D=175℃/210℃/220℃/220℃
Ad setting temperature: C1/C2/C3/D=100℃/160℃/220℃/220℃
LLDPE setting temperature: C1/C2/C3/D=150℃/200℃/210℃/220℃
Die 300mm width coat hanger die (manufactured by Plastic Engineering Research Institute)
<Adhesion criteria>
A: 600g/15cm or more B: 450g/15cm or more and less than 600g/15cm C: 300g/15cm or more and less than 450g/15cm D: Less than 300g/15cm

<Consideration>
As shown in Table 3, the resin composition of Reference Comparative Example 3, which does not contain aluminum ions, has an insufficient effect of suppressing the generation of lumps, and has poor heat and light resistance (reduction rate of elongation at break) and microplastics. The chemical resistance (mass loss in the evaluation after the heat and light resistance test) was also relatively large. On the other hand, the resin composition of Reference Comparative Example 1, which contained a small amount of aluminum ions, tended to be improved compared to the resin composition of Reference Comparative Example 3, but the improvement effect was low. . In addition, the resin composition of Reference Comparative Example 2 containing a large amount of aluminum ions did not have an improved effect of suppressing the generation of lumps. In contrast, each resin composition of Reference Examples 1 to 6 has a content (b) of aluminum ions (B) per 1 g of EVOH (A) in a range of 0.002 μmol/g or more and 0.17 μmol/g or less. It can be seen that the resin composition of Reference Comparative Example 1, which contained a small amount of aluminum ions, was further improved in the effect of suppressing lumps, heat resistance, light resistance, and resistance to microplastic formation.

Tables 4-10 are results using other EVOHs. From these results, similarly to the results in Table 3, when the content (b) of aluminum ions (B) per 1 g of EVOH (A) is within the range of 0.002 μmol/g or more and 0.17 μmol/g or less, It can be seen that the effect of suppressing lumps, heat resistance and light resistance, and resistance to forming microplastics are improved.

As shown in Table 3, the improvement effect was insufficient when the content of aluminum ions was low (0.02 ppm, 0.001 μmol/g), so in Tables 4 to 10, aluminum Based on the reference comparative example with an ion content of 0.02 ppm (0.001 μmol/g), those that are improved from this are evaluated as "+", and those that are not improved are evaluated as "-", and these are evaluated as Shown in the table.

On the other hand, as shown in Table 11, if the total content (i + ii) of terminal carboxylic acid units and terminal lactone ring units is too small, even if the content of aluminum ions is adjusted, the The mass loss was 14.0% by mass or more, and it did not have sufficient resistance to forming microplastics. Furthermore, as shown in Table 12, if the total content (i+ii) of terminal carboxylic acid units and terminal lactone ring units is too large, even if the content of aluminum ions is adjusted, the evaluation will be D. However, the occurrence of pimples could not be sufficiently suppressed.

From the above results, when the total content (i + ii) of terminal carboxylic acid units and terminal lactone ring units per 1 g of EVOH (A) is within the range of 14 μmol/g to 78 μmol/g, per 1 g of EVOH (A) By setting the content (b) of aluminum ions (B) within the range of 0.002 μmol/g or more and 0.17 μmol/g or less, the generation of lumps during melt molding is suppressed, and sufficient heat and light resistance is achieved. It can be seen that this is a resin composition that can be used to obtain a molded article that does not easily turn into microplastics after disposal, and that has sufficiently improved each of the above characteristics compared to a resin composition that uses the same EVOH. .

In addition, as shown in Table 13, by further containing at least one compound selected from the group consisting of cinnamic acids and conjugated polyene compounds with a molecular weight of 1,000 or less in addition to aluminum ions, heat and light resistance and microplastics can be improved. It can be seen that the corrosion resistance is further improved.

As shown in Table 14, when comparing Reference Example 8 and Reference Example 34, in which almost the same EVOH was used except for the lactone ring unit ratio, Reference Example 8, in which EVOH-B with a high lactone ring unit ratio was used, was It can be seen that the material has high heat resistance, light resistance, and microplasticization resistance.

As shown in Tables 15 and 16, the resin compositions of Examples 1 to 10 also suppressed the occurrence of lumps during melt molding, had sufficient heat and light resistance, and were molded products that were difficult to turn into microplastics after disposal. This is a resin composition that can be obtained, and the above characteristics are sufficiently improved compared to those using the same EVOH. Further, each of the resin compositions of Examples 1 to 10 had a large discharge amount during melt molding, and a molded article (film) with suppressed coloring could be obtained.

In addition, in Table 16, "evaluation before heat resistance and light resistance test" and "evaluation after heat and light resistance test", the same type of EVOH was used and a reference sample with an aluminum ion content of 0.02 ppm (0.001 μmol/g) was used. Based on the comparative example, those that are improved are shown as "+", and those that are not improved are shown as "-". That is, the "improvement" column in Table 16 does not indicate whether or not there was an improvement compared to the comparative example in Table 16. For example, Example 10 using EVOH-F shows whether or not it was improved over Reference Comparative Example 12. However, in Tables 15 and 16, for example, by comparing Comparative Examples 1 and 2 with Example 1, it is possible to confirm the improvement effect due to the difference in composition only in the content of aluminum ions.

Furthermore, in addition to the resin compositions of Examples 1 to 10, for example, by mixing a predetermined amount of nonionic surfactant (N) to the resin compositions of Reference Examples 1 to 34, the resin compositions of the present invention can be prepared. From the results of Reference Examples 1 to 34, such resin compositions also suppress the generation of lumps during melt molding, have sufficient heat and light resistance, and do not turn into microplastics after disposal. It is clear that this is a resin composition from which a molded object with difficulty can be obtained, and that each of the above characteristics is sufficiently improved compared to a resin composition using the same EVOH. Therefore, even if the resin composition contains EVOH (A), aluminum ion (B), and nonionic surfactant (N) other than the resin compositions of Examples 1 to 10, carboxylic acid units per 1 g Using EVOH (A) in which the total content (i + ii) of (I) and lactone ring unit (II) is 14 μmol/g or more and 78 μmol/g or less, the content of aluminum ions (B) per 1 g of EVOH (A) (b) is adjusted to within the range of 0.002 μmol/g to 0.17 μmol/g, and the content of the nonionic surfactant (N) is also within the specified range. The results of Reference Examples 1 to 34 sufficiently demonstrate that it is possible to obtain a molded product with improved properties and resistance to microplastic formation, a large discharge rate during melt molding, and suppressed coloring. Conceivable.

The resin composition of the present invention is useful as a molding material for various molded bodies, laminates, and the like.

Claims (13)

A resin composition containing an ethylene-vinyl alcohol copolymer (A), an aluminum ion (B) and a nonionic surfactant (N),
At least a part of the ethylene-vinyl alcohol copolymer (A) has at least one of a carboxylic acid unit (I) and a lactone ring unit (II) located at the end of the polymer,
The total content (i+ii) of carboxylic acid units (I) and lactone ring units (II) per 1 g of ethylene-vinyl alcohol copolymer (A) is 14 μmol/g or more and 78 μmol/g or less,
The content (b) of aluminum ions (B) per 1 g of ethylene-vinyl alcohol copolymer (A) is 0.002 μmol/g or more and 0.17 μmol/g or less,
A resin composition in which the content (n) of a nonionic surfactant (N) based on the ethylene-vinyl alcohol copolymer (A) is 0.1 ppm or more and 1,000 ppm or less. The ratio ((i+ii)/b) of the total content (i+ii) of carboxylic acid units (I) and lactone ring units (II) to the content (b) of aluminum ions (B) is 180 or more and 20,000 or less The resin composition according to claim 1. The resin composition according to claim 1 or 2, wherein the aluminum ion (B) is derived from a fatty acid aluminum salt having 5 or less carbon atoms. further containing at least one compound (C) selected from the group consisting of cinnamic acids and conjugated polyene compounds with a molecular weight of 1,000 or less,
The resin composition according to any one of claims 1 to 3, wherein the content (c) of the compound (C) relative to the ethylene-vinyl alcohol copolymer (A) is 1 ppm or more and 1,000 ppm or less. A claim in which the ratio (ii/(i+ii)) of the content (ii) of the lactone ring unit (II) to the total content (i+ii) of the carboxylic acid unit (I) and the lactone ring unit (II) is 40 mol% or more The resin composition according to any one of items 1 to 4. According to any one of claims 1 to 5, the nonionic surfactant (N) is at least one type selected from the group consisting of an ether type, an aminoether type, an ester type, an ester/ether type, and an amide type. The resin composition described. The nonionic surfactant (N) is polyoxyalkylene alkyl ether, polyoxyalkylene alkenyl ether, polyoxyethylene styrenated phenyl ether, polyoxyalkylene alkylamine, polyoxyalkylene alkenylamine, polyoxyalkylene alkyl ester, polyoxy The group consisting of alkylene alkenyl esters, sorbitan alkyl esters, sorbitan alkenyl esters, polyoxyethylene sorbitan alkyl esters, polyoxyethylene sorbitan alkenyl esters, glycerol alkyl esters, glycerol alkenyl esters, polyglycerin alkyl esters, polyglycerin alkenyl esters, and higher fatty acid amides The resin composition according to any one of claims 1 to 6, which is at least one selected from the following. A claim further comprising 0.005% by mass or more and 50% by mass or less of at least one additive selected from the group consisting of antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, and fillers. 8. The resin composition according to any one of items 1 to 7. A molded article formed from the resin composition according to any one of claims 1 to 8. A laminate comprising a layer made of the resin composition according to any one of claims 1 to 8 and at least one other layer. Production of the resin composition according to any one of claims 1 to 8, comprising a step of melt-kneading a mixture containing an ethylene-vinyl alcohol copolymer (A), a nonionic surfactant (N), and water. Method. The method for producing a resin composition according to claim 11, wherein the content of water in the mixture is 0.1 parts by mass or more and 50 parts by mass or less based on 100 parts by mass of the ethylene-vinyl alcohol copolymer (A). The resin composition according to claim 11 or 12, further comprising the step of obtaining the mixture by adding an aqueous solution or aqueous dispersion containing a nonionic surfactant (N) to the ethylene-vinyl alcohol copolymer (A). How things are manufactured.

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