JP2020105512A - Ethylene-vinyl alcohol-based copolymer resin composition, multilayer structure, and package - Google Patents

Abstract

To provide an ethylene-vinyl alcohol-based copolymer resin composition that has excellent shock resistance and light resistance, and an excellent adhesion strength without being combined with a resin other than the ethylene-vinyl alcohol-based copolymer.SOLUTION: The ethylene-vinyl alcohol-based copolymer resin composition is provided that is a resin composition containing an ethylene-vinyl alcohol-based copolymer (A), an acetic acid and/or a salt thereof (B), an aliphatic carboxylic acid (C) other than acetic acid, an aliphatic carboxylic acid metal salt (D) which is a metal salt of the aliphatic carboxylic acid (C), a cinnamic acid and/or a salt thereof (E), wherein: the metal species of the aliphatic carboxylic acid metal salt (D) is at least one selected from the elements belonging to the d-block elements of the fourth period of the long-form periodic table; the amount of each of the acetic acid and/or a salt thereof (B), the aliphatic carboxylic acid (C), the aliphatic carboxylic acid metal salt (D) and cinnamic acid and/or a salt thereof (E) fulfills the following formulas (1)-(3)on a weight basis. [Formula] (1): 0.015≤((D) content in terms of metal ion/(E) content in terms of cinnamic acid ion)≤50. [Formula](2):0.001≤((D)content in terms of metal ion/(B) content in terms of acetic acid ion)≤1.30. [Formula](3): 0.11≤((D) content in terms of metal ion equivalent/(C) content in terms of carboxylic acid ion)≤100.SELECTED DRAWING: None

Description

The present invention relates to an ethylene-vinyl alcohol copolymer (hereinafter sometimes referred to as “EVOH”) resin composition, and more specifically, EVOH having excellent impact resistance and light resistance, and also excellent adhesive strength. The present invention relates to a resin composition.

In EVOH, hydroxyl groups abundantly contained in the molecular chain form strong hydrogen bonds to form a crystal part, and the crystal part prevents oxygen from entering from the outside. Is shown. This EVOH is generally used as an intermediate layer of a laminated body in which resins are laminated, and is used as various packages.

As described above, EVOH has excellent gas barrier properties, but on the other hand, it tends to be brittle because it has abundant hydroxyl groups in the molecular chain and high crystallinity, and the EVOH layer in the package is cracked or pinholes occur due to impact or the like. It may be destroyed.

Therefore, for the purpose of improving the impact resistance of EVOH, for example, Patent Documents 1 and 2 disclose a laminated package having a resin composition layer composed of EVOH and an ethylene-vinyl acetate copolymer. Further, Patent Documents 3 and 4 disclose a laminate having a resin composition layer composed of a partially saponified product of EVOH and an ethylene-vinyl acetate copolymer.

In addition, since the multilayer structure using EVOH has excellent transparency, it transmits not only visible light but also ultraviolet light, which causes a problem that the packaged contents are deteriorated by ultraviolet light. It may end up. In particular, when the multilayer structure is used as a food packaging material, the food that is the content is exposed to UV-B and UV-C ultraviolet rays having a wavelength region of less than 320 nm, and as a result, the food itself is significantly deteriorated. It has been known.

Therefore, by adding a water-soluble ultraviolet absorber to a resin film such as polyvinyl alcohol, which is a type of film having gas barrier properties, the transparency is excellent, and photodegradation of the contents due to ultraviolet transmission is prevented. A technique for preventing it has been proposed (for example, see Patent Document 5).

JP-A-61-220839 JP 62-152847 A JP-A-1-279949 JP-A-3-192140 JP-A-51-132259

However, in the above Patent Documents 1 to 4, a part of EVOH is replaced with a resin other than EVOH and blended, so that the proportion of EVOH in the resin composition decreases, and the gas barrier property derived from EVOH tends to decrease.
In addition, in the techniques described in Patent Documents 1 to 4 above, although the impact resistance is excellent (the EVOH layer is unlikely to break), since it has excellent transparency, the content ( UV degradation of food etc. may occur.

Then, in the technique described in Patent Document 5, when used as a packaging material for a long period of time, the ultraviolet absorbent bleeds out due to the content, and the appearance is deteriorated, the ultraviolet absorbing effect is deteriorated, and odor is generated. Such problems may occur, and further improvements have been demanded.
Further, in the technique described in Patent Document 5, the impact resistance against a drop or a collision during long-term transportation or during handling may be insufficient, and problems such as oxidative deterioration of contents (food etc.) may occur. ..

In recent years, with the spread of internet shopping and the economic growth of developing countries, the borderless distribution of goods has been rapidly progressing, and the transportation period of foods and drugs tends to be prolonged. There is a demand for a multilayer structure (packaging material) having a layer made of an EVOH resin composition that has both high impact resistance against drops and collisions, excellent light resistance, and excellent adhesive strength and gas barrier properties.

Under the circumstances, the present invention provides an EVOH resin composition that is excellent in impact resistance and light resistance and is also excellent in adhesive strength without blending a resin other than EVOH.

However, the present inventor has conducted extensive studies in view of such circumstances, and as a result, from EVOH acetic acid and/or a salt thereof, an aliphatic carboxylic acid other than acetic acid, and an element belonging to the fourth period d block of the long periodic table. By using the metal salt of the above-mentioned aliphatic carboxylic acid having at least one selected metal species in combination with cinnamic acid and/or its salt, excellent impact resistance and adhesive strength when formed into a film, and color tone It was found that an EVOH resin composition having excellent stability and light resistance can be obtained.

That is, it is generally known that a fatty acid metal salt promotes thermal decomposition of EVOH and reduces impact resistance and color tone of the EVOH resin composition, and mechanical properties (impact resistance) and color tone of EVOH are known. A person skilled in the art would avoid blending EVOH with a fatty acid metal salt for the purpose of improvement. However, when the present inventor used EVOH in combination with acetic acid and/or a salt thereof, an aliphatic carboxylic acid other than acetic acid and a specific metal salt thereof, cinnamic acid and/or a salt thereof so as to satisfy a specific relationship, , And found that its mechanical properties (impact resistance) and color tone were improved contrary to conventional expectations.

Thus, the present invention provides EVOH (A), acetic acid and/or a salt thereof (B), an aliphatic carboxylic acid (C) other than acetic acid, and an aliphatic carboxylic acid which is a metal salt of the above aliphatic carboxylic acid (C). A resin composition containing an acid metal salt (D), cinnamic acid and/or a salt thereof (E), wherein the metal species of the aliphatic carboxylic acid metal salt (D) is a long period type periodic table fourth period. At least one selected from the elements belonging to the d block, the acetic acid and/or salt thereof (B), the aliphatic carboxylic acid (C), the aliphatic carboxylic acid metal salt (D), cinnamic acid and/or The first gist is an EVOH resin composition in which various contents of the salt (E) satisfy the following formulas (1) to (3) on a weight basis.
[Formula] 0.015 ≤ ((D) metal ion equivalent content/(E) cinnamic acid ion equivalent content) ≤ 50 (1)
[Formula] 0.001 ≤ ((D) metal ion-equivalent content/(B) acetate ion-equivalent content) ≤ 1.30 (2)
[Formula] 0.11≦((D) metal ion converted content/(C) carboxylate ion converted content)≦100 (3)

In addition, a multilayer structure having a layer made of the EVOH resin composition according to the first aspect is referred to as a second aspect, and a package including the multilayer structure according to the second aspect is referred to as a third aspect. ..

The EVOH resin composition of the present invention is an ethylene-vinyl alcohol copolymer, that is, EVOH (A), acetic acid and/or its salt (B), the above aliphatic carboxylic acid (C), and the above aliphatic carboxylic acid metal salt. A resin composition containing (D), cinnamic acid and/or a salt thereof (E), wherein the metal species of the aliphatic carboxylic acid metal salt (D) is contained in a block d of the fourth cycle of the long periodic table. It is at least one selected from the elements to which it belongs, and the acetic acid and/or salt thereof (B), the aliphatic carboxylic acid (C), the aliphatic carboxylic acid metal salt (D), cinnamic acid and/or its salt ( Since various contents of E) satisfy the following formulas (1) to (3) on a weight basis, they are excellent in impact resistance and adhesive strength when formed into a film, and also in color tone stability and light resistance. Are better.
[Formula] 0.015 ≤ ((D) metal ion equivalent content/(E) cinnamic acid ion equivalent content) ≤ 50 (1)
[Formula] 0.001 ≤ ((D) metal ion-equivalent content/(B) acetate ion-equivalent content) ≤ 1.30 (2)
[Formula] 0.11≦((D) metal ion converted content/(C) carboxylate ion converted content)≦100 (3)

The content of the cinnamic acid and/or its salt (E) in terms of cinnamic acid ion is such that the ethylene-vinyl alcohol copolymer (A), the acetic acid and/or its salt (B), and the fat are The color stability is further improved when the content is 1 to 1000 ppm with respect to the total content of the aromatic carboxylic acid (C), the aliphatic carboxylic acid metal salt (D), and the cinnamic acid and/or its salt (E). It has excellent properties.

The content of the aliphatic carboxylic acid metal salt (D) in terms of metal ion is such that the ethylene-vinyl alcohol copolymer (A), the acetic acid and/or its salt (B), the aliphatic carboxylic acid. When the content is 1 to 500 ppm with respect to the total content of the acid (C), the aliphatic carboxylic acid metal salt (D), the cinnamic acid and/or its salt (E), the impact resistance and the Excellent adhesive strength.

The content of the aliphatic carboxylic acid (C) in terms of carboxylic acid ion is such that the ethylene-vinyl alcohol copolymer (A), the acetic acid and/or its salt (B), the aliphatic carboxylic acid ( C), with respect to the total content of the aliphatic carboxylic acid metal salt (D), the cinnamic acid and/or its salt (E), 0.001 to 450 ppm, the impact resistance is further improved. Excellent and excellent color stability.

The content of the acetic acid and/or its salt (B) in terms of acetate ion is such that the ethylene-vinyl alcohol copolymer (A), the acetic acid and/or its salt (B), and the above aliphatic carvone. When the amount of the acid (C), the aliphatic carboxylic acid metal salt (D), the cinnamic acid and/or the salt thereof (E) is 10 to 2000 ppm, the film is further formed. It has excellent impact resistance and adhesive strength, and also excellent color stability.

Further, the content ratio ((E) of cinnamic acid in terms of cinnamic acid ion of cinnamic acid and/or salt thereof (E) to the content of acetic acid and/or salt thereof (B) in terms of acetate ion) When the content in terms of ion/content in terms of acetic acid ion of (B)) is 0.0001 to 10000 on a weight basis, the impact resistance when forming a film is further excellent, and the color tone stability and light resistance are further improved. It is also excellent in sex.

Further, when the elongation viscosity at 210° C. and 100 S ⁻¹ of the ethylene-vinyl alcohol-based copolymer resin composition satisfies the following formula (4), the impact resistance when the film is formed is further improved. Is excellent.
[Formula] 500≦extension viscosity [Pa·s]≦48000 (4)

Further, in the ethylene-vinyl alcohol-based copolymer resin composition further containing boric acid and/or its salt (F), the boric acid and/or its salt (F) is the above-mentioned ethylene-vinyl alcohol-based resin composition. Copolymer (A), the acetic acid and/or salt thereof (B), the aliphatic carboxylic acid (C), the aliphatic carboxylic acid metal salt (D), the cinnamic acid and/or its salt (E), When it is 0.001 to 500 ppm in terms of boron based on the total content of the boric acid and/or its salt (F), the impact resistance during film formation is further excellent, and further It also has excellent color stability.

Further, the multilayer structure obtained by using the EVOH resin composition is an excellent multilayer structure having excellent mechanical properties (impact resistance) and improved color tone reduction and adhesive strength reduction during melt molding. ..

Furthermore, since the packaging body of the present invention is composed of the above-mentioned multilayer structure, the resulting packaging body is also excellent in impact resistance and adhesive strength, and is also excellent in color tone stability.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below, but these show one example of preferred embodiments.

The EVOH resin composition of the present invention contains EVOH (A) as a main component, acetic acid and/or its salt (B), an aliphatic carboxylic acid (C) other than acetic acid, and a metal salt of the above aliphatic carboxylic acid (C). The aliphatic carboxylic acid metal salt (D), cinnamic acid and/or its salt (E) are included. In the EVOH resin composition of the present invention, the base resin is EVOH (A), and the EVOH (A) content in the EVOH resin composition is usually 60% by weight or more, preferably 70% by weight or more, It is more preferably 80% by weight or more, and particularly preferably 90% by weight or more. Hereinafter, each component will be described.
In the present specification, “and/or” means at least one, and in the case of “X and/or Y”, it means three kinds of only X, only Y, and X and Y.

<EVOH (A)>
EVOH (A) used in the present invention is usually a resin obtained by copolymerizing ethylene and a vinyl ester-based monomer and then saponifying it, and is an ethylene-vinyl alcohol-based copolymer or an ethylene-vinyl acetate-based copolymer. It is a water-insoluble thermoplastic resin known as a saponified copolymer. As the polymerization method, any known polymerization method, for example, solution polymerization, suspension polymerization, emulsion polymerization or the like can be used, but solution polymerization using methanol as a solvent is generally used. Saponification of the obtained ethylene-vinyl ester copolymer can also be carried out by a known method.

That is, the EVOH (A) used in the present invention mainly contains ethylene structural units and vinyl alcohol structural units, and contains a small amount of vinyl ester structural units remaining without being saponified. EVOH is also generally referred to as "saponified ethylene-vinyl ester copolymer".

As the vinyl ester-based monomer, vinyl acetate is typically used because it is easily available on the market and the efficiency of treating impurities during production is good. In addition, examples of vinyl ester-based monomers include vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl versatate, etc. And the like, and aromatic vinyl esters such as vinyl benzoate. Among them, an aliphatic vinyl ester having preferably 3 to 20 carbon atoms, more preferably 4 to 10 carbon atoms, and particularly preferably 4 to 7 carbon atoms. These are usually used alone, but if necessary, a plurality of types may be used simultaneously.

The content of the ethylene structural unit in the EVOH (A) is a value measured based on ISO14663, and is usually 20 to 60 mol%, preferably 21 to 55 mol%, more preferably 22 to 50 mol%, and particularly preferably. Is 23 to 45 mol %. If the content is too small, the gas barrier property at high humidity and the melt moldability tend to be lowered, and conversely, if it is too high, the gas barrier property tends to be lowered.

The saponification degree of the vinyl ester component in the EVOH (A) is a value measured based on JIS K6726 (however, EVOH is a solution uniformly dissolved in a water/methanol solvent), and usually 90 to 100 mol%. %, preferably 95 to 100 mol %, particularly preferably 99 to 100 mol %. If the degree of saponification is too low, the gas barrier properties, thermal stability, moisture resistance, etc. tend to deteriorate.

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

The EVOH (A) used in the present invention further contains a structural unit derived from a comonomer shown below in addition to an ethylene structural unit, a vinyl alcohol structural unit (including an unsaponified vinyl ester structural unit). May be. Examples of the comonomer include α-olefins such as propylene, isobutene, α-octene, α-dodecene and α-octadecene; 3-butene-1-ol, 4-penten-1-ol, 3-butene-1, Hydroxy group-containing α-olefins such as 2-diols and their esterified products, hydroxy group-containing α-olefin derivatives such as acylated products; 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2- Hydroxymethylvinylidene diacetates such as methylenepropane and 1,3-dibutyronyloxy-2-methylenepropane; unsaturated carboxylic acids or salts thereof, partial alkyl esters, complete alkyl esters, nitriles, amides or anhydrides; unsaturated Examples thereof include sulfonic acid or salts thereof; vinylsilane compounds; vinyl chloride; styrene and the like.

Further, as the above-mentioned EVOH (A), EVOH which has been “post-modified” such as urethanated, acetalized, cyanoethylated or oxyalkylenated can also be used.

Among the modified EVOH (A) as described above, EVOH (A) having a primary hydroxyl group introduced into the side chain by copolymerization has good secondary moldability such as stretching treatment and vacuum/pressure molding. Is preferable, and EVOH (A) having a 1,2-diol structure in its side chain is particularly preferable.

The EVOH (A) used in the present invention may be a mixture with other different EVOH, and such other EVOH having different ethylene structural unit content and different saponification degree. , Those having different melt flow rates (MFR) (210° C., load 2160 g), those having different other copolymerization components, those having different modification amounts (for example, the content of structural units containing primary hydroxyl groups in their side chains is different) Thing) etc. can be mentioned.

<Acetic acid and/or its salt (B)>
The EVOH resin composition of the present invention contains acetic acid and/or its salt (B). That is, the EVOH resin composition of the present invention contains at least one selected from the group consisting of acetic acid and acetate.

Specific examples of the acetic acid and/or its salt (B) include acetic acid, sodium acetate, potassium acetate, calcium acetate, magnesium acetate, manganese acetate, copper acetate, cobalt acetate, zinc acetate, and the like. These can be used alone or in combination of two or more. Among them, acetic acid, sodium acetate, potassium acetate, calcium acetate and magnesium acetate are preferable, acetic acid, sodium acetate and potassium acetate are more preferable, and acetic acid and sodium acetate are more preferable. Especially preferred is sodium acetate.

The content of acetic acid and/or its salt (B) in terms of acetate ion is EVOH (A), acetic acid and/or its salt (B), the above aliphatic carboxylic acid (C), and the above aliphatic carboxylic acid metal. The content of the salt (D), cinnamic acid and/or its salt (E) is usually 10 to 2000 ppm, preferably 15 to 1500 ppm, particularly preferably 20 to 1000 ppm, and particularly preferably 25 to It is 650 ppm.
If the content is too low, the adhesive strength may be lowered due to the thermal decomposition product of the aliphatic carboxylic acid metal salt (D), or the effects of the present invention may not be sufficiently obtained. If the content is too high, However, the stability of the color tone during melt molding tends to decrease, and the effects of the present invention tend not to be sufficiently obtained.

The content of acetic acid and/or its salt (B) in terms of acetate ion can be measured by a known analysis method. For example, it can be measured using liquid chromatography mass spectrometry (LC/MS), gas chromatography mass spectrometry (GC/MS), or the like.

<Aliphatic carboxylic acid (C) other than acetic acid>
The EVOH resin composition of the present invention contains an aliphatic carboxylic acid (C) other than acetic acid, and the number of carbon atoms of the aliphatic carboxylic acid (C) is usually 3 to 30, preferably 4 to 22. , Particularly preferably 5 to 14. When the carbon number of the aliphatic carboxylic acid (C) is within the above range, the effect of the present invention tends to be obtained more effectively.

Specific examples of the aliphatic carboxylic acid (C) include aliphatic monocarboxylic acid, aliphatic dicarboxylic acid, and aliphatic tricarboxylic acid. More specifically, for example, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, pentadecyl acid, palmitic acid, margaric acid, stearic acid, arachidic acid, henicosyl acid. Acids, behenic acid, lignoceric acid, montanic acid, melissic acid, tartronic acid, glyceric acid, hydroxybutyric acid, malic acid, tartaric acid, gluconic acid, mevalonic acid, pantoic acid and other saturated aliphatic monocarboxylic acids; linoleic acid, linolenic acid , Pinolenic acid, eleostearic acid, isostearic acid, isononanoic acid, 2-ethylhexanoic acid, 2-heptylundecanoic acid, 2-octyldodecanoic acid, palmitoleic acid, sapienoic acid, oleic acid, elaidic acid, vaccenic acid, gadoleic acid Unsaturated aliphatic monocarboxylic acids such as eicosenoic acid, erucic acid, nervonic acid and ricinoleic acid; saturated aliphatic dicarboxylic acids such as succinic acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid, eicosadienic acid, Unsaturated aliphatic dicarboxylic acids such as docosadienoic acid; saturated aliphatic tricarboxylic acids such as citric acid, isocitric acid, and aconitic acid. These aliphatic carboxylic acids (D) can be used alone or in combination of two or more. Of these, from the viewpoint of thermal stability (increased viscosity during melt molding and prevention of fisheye generation), an aliphatic monocarboxylic acid containing one carboxy group is preferable, and a saturated aliphatic monocarboxylic acid is more preferable. And more preferably a saturated aliphatic monocarboxylic acid having 6 to 22 carbon atoms, particularly preferably stearic acid, caproic acid, caprylic acid, lauric acid, behenic acid, and particularly preferably caproic acid and capryl. Acid, lauric acid.

The content of the aliphatic carboxylic acid (C) in terms of carboxylate ion is EVOH (A), acetic acid and/or a salt thereof (B), the aliphatic carboxylic acid (C), the aliphatic carboxylic acid metal salt. The total content of (D), cinnamic acid and/or its salt (E) is usually 0.001 to 950 ppm, preferably 0.001 to 450 ppm, more preferably 0.01 to 360 ppm. And particularly preferably 0.1 to 250 ppm, particularly preferably 0.5 to 200 ppm.
If the content is too small, the thermal stability of the aliphatic carboxylic acid metal salt (D) tends to be insufficient, and as a result, the effect of the present invention tends not to be sufficiently obtained, and if the content is too large, melting occurs. The stability of color tone at the time of molding tends to be lowered, and the aliphatic carboxylic acid (C) itself acts as a plasticizer, so that the effects of the present invention tend not to be sufficiently obtained.

The content ratio of the acetic acid and/or its salt (B) in terms of acetate ion to the content of the aliphatic carboxylic acid (C) in terms of carboxylate ion (acetic acid ion of acetic acid and/or its salt (B)) The converted content/the converted content of the carboxylic acid ion of the aliphatic carboxylic acid (C) is usually 0.0001 to 10,000, preferably 0.001 to 5,000, and more preferably 0.1 to 10,000 on a weight basis. It is 1000, particularly preferably 1 to 800, particularly preferably 1 to 600.
When the content ratio is within the above range, the effect of the present invention tends to be more remarkably obtained. When the content ratio is less than the above range, the color tone stability during melt molding is insufficient, or the adhesive strength is insufficient. If it exceeds the above range, the effect of the present invention tends not to be sufficiently obtained.

<Aliphatic carboxylic acid metal salt (D)>
The EVOH resin composition of the present invention contains an aliphatic carboxylic acid metal salt (D) which is a metal salt of an aliphatic carboxylic acid (C) other than the acetic acid.

It is essential that the metal species of the aliphatic carboxylic acid metal salt (D) is an element belonging to the fourth period d block in the long periodic table. Among them, chromium, cobalt, nickel, copper, and zinc are preferable, and particularly preferable is zinc, which has a particularly excellent effect and is inexpensive and easily available.

Although the reason why the excellent effect is obtained by using the aliphatic carboxylic acid metal salt (D) is not clear, the metal species of the aliphatic carboxylic acid metal salt (D) is a long period type periodic table fourth period d block. By being at least one selected from the group consisting of elements belonging to, the excessive thermal decomposition that causes deterioration of mechanical properties (impact resistance) is appropriately suppressed, and formed when the EVOH resin composition is subjected to multilayer coextrusion molding. It is presumed that the higher order structures such as the molecular orientation and the crystal structure are highly homogenized, and as a result, the mechanical properties (impact resistance) are improved.

As the anion species of the aliphatic carboxylic acid metal salt (D), those exemplified as the aliphatic carboxylic acid (C) other than acetic acid can be used, but in the present invention, the aliphatic carboxylic acid metal salt (D) is used. It is important that the anionic species of) and the aliphatic carboxylic acid (C) are the same species. An EVOH resin having excellent impact resistance and having a higher color tone stability even when melt-molded because the anionic species of the aliphatic carboxylic acid metal salt (D) and the aliphatic carboxylic acid (C) are the same species It can be a composition.
When the EVOH resin composition of the present invention contains a plurality of aliphatic carboxylic acids (C) or a plurality of aliphatic carboxylic acid metal salts (D), at least one kind of aliphatic carboxylic acid (C) and fat The anionic species of the group carboxylic acid metal salt (D) may be the same.

It is not clear why the aliphatic carboxylic acid (C) and the aliphatic carboxylic acid metal salt (D) have the same anion species to obtain excellent effects, but a specific amount of the aliphatic carboxylic acid ( By using C) and the aliphatic carboxylic acid metal salt (D) in combination, the dispersibility of the aliphatic carboxylic acid metal salt (D) is remarkably improved, and more excellent effects of the present invention can be obtained. Presumed to be. Further, it is considered that the aliphatic carboxylic acid (C) interacts with the metal species of the aliphatic carboxylic acid metal salt (D) and exists in a state like a metal complex. When the anionic species is the same as the aliphatic carboxylic acid (C), it is possible to exist in a more energetically stable state, and it has excellent thermal stability even when melt-molded, resulting in an EVOH resin composition. It is assumed that the mechanical properties (impact resistance) of the product are improved.

Moreover, when the carbon number of the aliphatic carboxylic acid (C) and the aliphatic carboxylic acid metal salt (D) is usually 3 to 30, preferably 4 to 22, and particularly preferably 5 to 14, more notably. Mechanical properties (impact resistance) tend to be improved. Although the reason for this is not clear, when the aliphatic carboxylic acid (C) and the aliphatic carboxylic acid metal salt (D) have carbon numbers within the above range, the aliphatic carboxylic acid (C) and the aliphatic carboxylic acid are not present. It is speculated that the acid metal salt (D) was more easily dispersed in the EVOH resin composition more uniformly, and as a result, the mechanical properties (impact resistance) of the EVOH resin composition were more significantly improved.

Further, the above-mentioned aliphatic carboxylic acid metal salt (D) alone tends to improve the impact resistance while decreasing the adhesive strength. Although the reason for this is not clear, the above-mentioned aliphatic carboxylic acid metal salt (D) alone has insufficient thermal stability, and thus the thermal decomposition of the aliphatic carboxylic acid metal salt (D) produced during melt molding. It is considered that the adhesive strength decreased depending on the object. On the other hand, in the present invention, the above-mentioned aliphatic carboxylic acid metal salt (D) is used in combination with acetic acid and/or its salt (B) to convert the thermal decomposition product of the above aliphatic carboxylic acid metal salt (D) into acetic acid and/or Alternatively, it is presumed that the salt (B) is captured and dispersed to suppress the decrease in adhesive strength.

The content of the aliphatic carboxylic acid metal salt (D) in terms of metal ion is EVOH (A), acetic acid and/or its salt (B), the aliphatic carboxylic acid (C), the aliphatic carboxylic acid metal. The total content of the salt (D), cinnamic acid and/or its salt (E) is usually 1 to 500 ppm, preferably 5 to 300 ppm, particularly preferably 10 to 250 ppm, and particularly It is preferably 30 to 200 ppm. If the content of the aliphatic carboxylic acid metal salt (D) is too small, the effect of the present invention tends not to be sufficiently obtained, and if the content is too large, the adhesive strength is lowered and the color tone at the time of melt molding is decreased. Stability tends to decrease.

The content of the above-mentioned aliphatic carboxylic acid (C) in terms of carboxylate ion and the content of the above-mentioned metal salt of aliphatic carboxylic acid (D) in terms of metal ion can be measured by a known analysis method. .. For example, it can be determined by the following methods alone or by combining them.
(I) Content of metal salt of aliphatic carboxylic acid (D) in terms of metal ion: A dried sample is precisely weighed, placed in a constant weight platinum evaporation dish, carbonized with an electric heater, and then heated with a gas burner. Then, it is baked until no smoke is emitted, and the platinum evaporation dish is placed in an electric furnace and heated to completely incinerate. After cooling this, hydrochloric acid and pure water are added to the ash, heated and dissolved in an electric heater, poured into a volumetric flask, and the volume is made constant with pure water to prepare a sample for atomic absorption analysis. The content of the aliphatic carboxylic acid metal salt (D) in terms of metal ion can be determined by quantitatively analyzing the amount of metal in the sample for atomic absorption analysis by the atomic absorption method.
(Ii) Content of aliphatic carboxylic acid (C) in terms of carboxylate ion: First, using liquid chromatography mass spectrometry (LC/MS), gas chromatography mass spectrometry (GC/MS), or the like, The content (Cx) of the aliphatic carboxylic acid (C) and its metal salt (D) in the EVOH resin composition in terms of carboxylic acid ion is quantified. Then, the content (Cy) of the aliphatic carboxylic acid metal salt (D) in terms of carboxylic acid ion is calculated from the content of the aliphatic carboxylic acid metal salt (D) in terms of metal ion. Then, the sum total (Cx) of the contents of the aliphatic carboxylic acid (C) and its metal salt (D) in terms of carboxylate ion and the content of the aliphatic carboxylic acid metal salt (D) in terms of carboxylate ion ( From the difference (Cy) ((Cx)-(Cy)), the content of the aliphatic carboxylic acid (C) in terms of carboxylate ion can be determined.

<Cinnamic acid and/or its salt (E)>
In the present invention, cinnamic acid and/or its salt (E) is contained. That is, the EVOH resin composition of the present invention contains at least one selected from the group consisting of cinnamic acid and cinnamic acid salts.

Examples of the cinnamic acid used in the present invention include cis-cinnamic acid and trans-cinnamic acid. From the viewpoint of stability and cost, trans-cinnamic acid is preferably used. Examples of the cinnamic acid salts include alkali metal cinnamates such as lithium cinnamate, sodium cinnamate and potassium cinnamate, alkaline earth metal cinnamates such as magnesium cinnamate, calcium cinnamate and barium cinnamate. Are listed. These cinnamic acids and/or salts thereof can be used alone or in combination of two or more. Of these, trans-cinnamic acid is preferably used alone.

The content of the cinnamic acid and/or its salt (E) in terms of cinnamic acid ion is EVOH (A), acetic acid and/or its salt (B), the above aliphatic carboxylic acid (C), and the above aliphatic carboxylic acid. The amount of the acid metal salt (D), cinnamic acid and/or its salt (E) is usually 1 to 1200 ppm, preferably 1 to 1000 ppm, more preferably 10 to 800 ppm, and It is preferably 15 to 500 ppm, particularly preferably 50 to 300 ppm, particularly preferably 100 to 200 ppm. If the content is too small, the light resistance tends to be lowered, and if the content is too large, odor generation during melt molding tends to be a problem.

The EVOH resin composition of the present invention is a ratio of the content of the aliphatic carboxylic acid metal salt (D) to the content of the cinnamic acid and/or its salt (E) in terms of cinnamic acid ion ((D)). /(E)) satisfies the following formula (1) on a weight basis.
[Formula] 0.015 ≤ ((D) metal ion equivalent content/(E) cinnamic acid ion equivalent content) ≤ 50 (1)
0.075≦((D)/(E))≦40, particularly preferably 0.15≦((D)/(E))≦30, particularly preferably 0.2≦((D)/ (E))≦20. When the value is within the above range, the effect of the present invention tends to be more remarkably obtained, and when it is out of the above range, the effect of the present invention tends to be insufficiently obtained.

The EVOH resin composition of the present invention is a ratio of the content of the aliphatic carboxylic acid metal salt (D) to the content of the acetic acid and/or its salt (B) in terms of acetate ion ((D)/( B)) satisfies the following formula (2) on a weight basis.
[Formula] 0.001 ≤ ((D) metal ion-equivalent content/(B) acetate ion-equivalent content) ≤ 1.30 (2)
Preferably 0.005≦((D)/(B))≦1.1, more preferably 0.005≦((D)/(B))≦1.0, and even more preferably 0.01≦( (D)/(B))≦0.8, particularly preferably 0.04≦((D)/(B))≦0.48, particularly preferably 0.05≦((D)/(B) )≦0.45. When such a value is within the above range, the effect of the present invention tends to be more remarkably obtained, and when it is smaller than the above range, the effect of the present invention tends to be insufficient, and above the above range, There is a tendency that the color tone stability during melt molding is insufficient or the adhesive strength is insufficient.

The EVOH resin composition of the present invention is a metal ion equivalent content ratio ((D)/(C) of the aliphatic carboxylic acid metal salt (D) with respect to the content of the aliphatic carboxylic acid (C) in terms of carboxylic acid ion. )) satisfies the following formula (3) on a weight basis.
[Formula] 0.11≦((D) metal ion converted content/(C) carboxylate ion converted content)≦100 (3)
Preferably 0.13≦((D)/(C))≦90, particularly preferably 0.15≦((D)/(C))≦80, particularly preferably 0.2≦((D)/( C))≦70. If such a value is within the above range, the effect of the present invention tends to be more remarkably obtained, and if it is less than the above range, the color tone stability during melt molding is insufficient, or the effect of the present invention is sufficient. If it exceeds the above range, the color tone stability during melt molding tends to be insufficient, or the moldability tends to be insufficient.

The content of the acetic acid and/or salt thereof (B), the aliphatic carboxylic acid (C), the aliphatic carboxylic acid metal salt (D), the cinnamic acid and/or its salt (E) is expressed by weight. It is not clear why excellent effects are obtained by satisfying (1) to (3), but the aliphatic carboxylic acid metal salt (D) and a specific amount of the aliphatic carboxylic acid having the same anionic species. While (C) has the effect of enhancing the dispersibility and thermal stability of the aliphatic carboxylic acid metal salt (D), when the content of the aliphatic carboxylic acid (C) is too large, the aliphatic carboxylic acid Since (C) itself acted as a plasticizer, it is presumed that the effect of the present invention (impact resistance improving effect) cannot be sufficiently obtained. Further, the specific amount of acetic acid and/or its salt (B) has the effect of capturing the thermal decomposition product of the above-mentioned aliphatic carboxylic acid metal salt (D) and suppressing the decrease in adhesive strength, while acetic acid and/or When the content of the salt (B) is too large, the thermal stability of EVOH (A) is remarkably lowered, the color stability is apt to be lowered, and the effect of the present invention (impact resistance improving effect) is sufficiently obtained. It is speculated that it cannot be done. Further, the specific amount of cinnamic acid and/or its salt (E) has an excellent ultraviolet absorption effect, and the above-mentioned acetic acid and/or its salt (B) cannot be completely captured, and the above-mentioned aliphatic carboxylic acid metal salt. It is presumed that the cinnamic acid and/or its salt (E) captures the thermal decomposition product of (D) and the thermal decomposition product of EVOH (A), and thus has the effect of suppressing a decrease in color tone. On the other hand, if the content of cinnamic acid and/or its salt (E) is too high, the effect of the present invention (impact resistance improving effect) will be caused by the thermal decomposition of cinnamic acid and/or its salt (E) itself. It is presumed that it may not be sufficiently obtained or that the stability of color tone may be easily deteriorated.

Further, the EVOH resin composition of the present invention preferably has an extensional viscosity at 210° C. and 100 S ⁻¹ satisfying the following formula (4) from the viewpoint of impact resistance.
[Formula] 850≦extension viscosity [Pa·s]≦48000 (4)
More preferably, 900≦elongation viscosity [Pa·s]≦30000, particularly preferably 950≦elongation viscosity [Pa·s]≦20000. When the value is within the above range, the effect of the present invention tends to be more remarkably obtained, and when the value is smaller than the above range, the effect of the present invention tends to be insufficient, and when the value is above the range, melting Moldability during molding tends to be insufficient.

It is not clear why the EVOH resin composition of the present invention has excellent extensional viscosity at 210° C. and 100 S ⁻¹ , which satisfies the formula (4), but 210 of the EVOH resin composition of the present invention is obtained. When the extensional viscosity at 100° C. and 100 S ⁻¹ satisfies the formula (4), the entangled structure of EVOH molecular chains appropriately formed in the EVOH resin composition is obtained by multi-layer coextrusion molding of the EVOH resin composition. In addition, it is presumed that the mechanical properties (impact resistance) are remarkably improved because the formation of higher-order structures such as the molecular orientation and the crystal structure of the EVOH resin composition is remarkably promoted.

<Evaluation method of extensional viscosity (Pa·s) of EVOH resin composition>
The extensional viscosity (Pa·s) of the EVOH resin composition of the present invention at 210° C. and 100 S ⁻¹ is measured by using a capillary rheometer using a Cogswell formula [Polymer Engineering Science, Volume 12, pages 64-73 (1972). ], it is possible to obtain by performing the measurement under the following conditions.

That is, the elongation viscosity (η _e ) and the elongation strain rate (dε/dt) are calculated by the following equations (5) to (7) proposed by Cogswell (Polymer Engineering Science, Volume 12, p. 64-73 (1972)). ) Can be used to calculate.
η _e =[9(n+1) ² P ₀ ² ]/[32 η _s (dγ/dt) ² ]... Equation (5)
dε/dt=4σ _s (dγ/dt)/[3(n+1)P ₀ ]... Expression (6)
σ _s =k(dγ/dt) ⁿ (7)
Where η _e is extensional viscosity, η _s is shear viscosity, dγ/dt is shear strain rate, dε/dt is extensional strain rate, σ _s is shear stress, k is a constant, index n is melt fracture or slip stick. It is obtained by performing fitting with a quadratic function, assuming that the shear stress and the shear strain rate follow a power law in a shear rate region (100≦dγ/dt≦1000) in which does not occur. P ₀ is a pressure loss generated in a die having a capillary length of 0, and is obtained by the Calay correction of the measurement result using two or more capillaries having different lengths.
Measuring device: RHEOGRAPH 20 manufactured by Gottfert
Measurement temperature: 210℃
Long die: length 10 mm, diameter 1 mm, inflow angle 180°
Short die: length 0.2mm, diameter 1mm, inflow angle 180°

<Boric acid and/or its salt (F)>
The EVOH resin composition of the present invention preferably contains the above boric acid and/or its salt (F). That is, the EVOH resin composition of the present invention preferably contains at least one selected from the group consisting of boric acid and borate.

The boric acid and/or its salt (F) is usually boric acid, a metal salt of boric acid such as calcium borate, cobalt borate, zinc borate (zinc tetraborate, zinc metaborate, etc.), Aluminum borate/potassium borate, ammonium borate (ammonium metaborate, ammonium tetraborate, ammonium pentaborate, ammonium octaborate, etc.), cadmium borate (cadmium orthoborate, cadmium tetraborate, etc.), potassium borate ( Potassium metaborate, potassium tetraborate, potassium pentaborate, potassium hexaborate, potassium octaborate, etc.), silver borate (silver metaborate, silver tetraborate, etc.), copper borate (cupric borate) , Copper metaborate, copper tetraborate, etc., sodium borate (sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate, sodium octaborate, etc.), lead borate (Lead metaborate, lead hexaborate, etc.), nickel borate (nickel orthoborate, nickel diborate, nickel tetraborate, nickel octaborate, etc.), barium borate (barium orthoborate, barium metaborate, dichloride) Barium borate, barium tetraborate, etc., bismuth borate, magnesium borate (magnesium orthoborate, magnesium diborate, magnesium metaborate, trimagnesium tetraborate, pentamagnesium tetraborate, etc.), manganese borate ( In addition to boric acid primary manganese borate, manganese metaborate, manganese tetraborate, etc., lithium borate (lithium metaborate, lithium tetraborate, lithium pentaborate, etc.), etc., borax, carnite, in-yoite, kotoishi , Suiyanite, borate minerals such as zyberite, and the like, among them, borax, boric acid, sodium borate, potassium borate, zinc borate, calcium borate, magnesium borate are preferred, and particularly preferred. , Boric acid, sodium borate, zinc borate, particularly preferably boric acid.

The content of boric acid and/or its salt (F) in terms of boron is EVOH (A), acetic acid and/or its salt (B), aliphatic carboxylic acid (C) other than acetic acid, and aliphatic carboxylic acid. The total content of the metal salt (D), cinnamic acid and/or its salt (E), boric acid and/or its salt (F) is usually 0.001 to 1000 ppm, preferably 0.001 to 600 ppm. More preferably 0.001-500 ppm, even more preferably 0.01-400 ppm, particularly preferably 0.05-330 ppm, even more preferably 0.1-250 ppm, particularly preferably 1-120 ppm. ..
If the content is too small, the effect of the present invention (impact resistance improving effect) tends not to be sufficiently obtained, and if the content is too large, the color tone is lowered, or fish eyes frequently occur during multilayer film formation. The effect of the invention (improvement in impact resistance) tends not to be sufficiently obtained.

Further, it is not clear why excellent effects are obtained by using a specific amount of boric acid and/or its salt (F), but boric acid and/or its salt (F) dispersed in the EVOH resin composition. However, when the EVOH resin composition is subjected to multi-layer coextrusion by forming a crosslinked structure between the EVOH molecular chains by interacting with the EVOH molecular chain, a higher order structure such as a molecular orientation or a crystal structure of the EVOH resin composition is formed. It is presumed that the mechanical properties (impact resistance) are significantly improved as a result, because the formation of the is more significantly promoted.
In addition, the thermal decomposition product of the aliphatic carboxylic acid metal salt (D) and the thermal decomposition product of the EVOH (A) that could not be captured by the acetic acid and/or its salt (B) were converted to boric acid and/or It is presumed that the salt (F) captures and suppresses the deterioration of the color tone.

The content of boric acid and/or its salt (F) in terms of boron can be measured by a known analysis method. For example, the amount of boron can be quantified by inductively coupled plasma optical emission spectrometry (ICP-AES) using a solution having a fixed volume after wet decomposition of the EVOH resin composition.

<Other thermoplastics>
The EVOH resin composition of the present invention contains, as a resin component, other thermoplastic resin in addition to EVOH (A) within a range of usually 30% by weight or less based on EVOH (A). May be.

Examples of the other thermoplastic resin include linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, ionomer, ethylene-propylene copolymer, polypropylene, polybutene, polypentene, and other olefins alone or Copolymers, polycyclic olefins, or polyolefin resins in a broad sense such as those obtained by graft-modifying homopolymers or copolymers of these olefins with unsaturated carboxylic acids or their esters, polystyrene resins, polyesters, polyamide resins, copolymers, Examples include polymerized polyamide resins, polyvinyl chloride, polyvinylidene chloride, acrylic resins, vinyl ester resins, chlorinated polyethylene, chlorinated polypropylene, and the like.

The α-olefin of the polyolefin-based resin may be a plant-derived α-olefin derived from bioethanol, or a non-plant-derived α-olefin, that is, a petroleum-derived α-olefin. May be used. Since a wide variety of petroleum-derived α-olefins are available, the physical properties and the like of the polyolefin resin can be easily adjusted by producing them using these. By using the plant-derived α-olefin, the degree of biomass of the final product can be further increased and the load on the environment can be reduced.

As a method for producing plant-derived ethylene and plant-derived α-olefins, sugar solution and starch obtained from plants such as sugar cane, corn and sweet potato are fermented by microorganisms such as yeast to produce bioethanol according to a conventional method. Then, this is heated in the presence of a catalyst, and plant-derived ethylene and plant-derived α-olefin (1-butene, 1-hexene, etc.) can be obtained by an intramolecular dehydration reaction or the like. Then, using the obtained plant-derived ethylene and plant-derived α-olefin, a plant-derived polyethylene resin can be produced in the same manner as the production of a petroleum-derived polyethylene resin.

The method for producing plant-derived ethylene, plant-derived α-olefin, and plant-derived polyethylene-based resin is described in detail, for example, in Japanese Patent Publication No. 2011-506628. Examples of the plant-derived polyethylene-based resin preferably used in the present invention include Green PE manufactured by Braskem SA.

In particular, when a multilayer structure comprising the EVOH resin composition of the present invention is produced and used as a food packaging material, the EVOH layer is eluted at the end of the packaging material after hot water treatment of the packaging material. In order to prevent this, it is preferable to add a polyamide resin. In the polyamide resin, the amide bond can form a network structure by interacting with at least one of the OH group and the ester group of EVOH, thereby preventing elution of the EVOH layer during hot water treatment. You can Therefore, when the EVOH resin composition of the present invention is used as a packaging material for retort foods or boiled foods, it is preferable to blend a polyamide resin.

As the polyamide-based resin, known ones can be used.
Specifically, for example, polycapramide (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-ω-aminononanoic acid (nylon 9), polyundecane amide (nylon 11), polylauryl lactam (nylon 12). ) And other homopolymers, among which polycapramide (nylon 6) is preferred. As the copolyamide resin, polyethylene diamine adipamide (nylon 26), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebacamide (nylon). 610), polyhexamethylene dodecamide (nylon 612), polyoctamethylene adipamide (nylon 86), polydecamethylene adipamide (nylon 108), caprolactam/lauryllactam copolymer (nylon 6/12), caprolactam /Ω-aminononanoic acid copolymer (nylon 6/9), caprolactam/hexamethylene diammonium adipate copolymer (nylon 6/66), lauryl lactam/hexamethylene diammonium adipate copolymer (nylon 12/66), Ethylenediamine adipamide/hexamethylene diammonium adipate copolymer (nylon 26/66), caprolactam/hexamethylene diammonium adipate/hexamethylene diammonium sebacate copolymer (nylon 66/610), ethylene ammonium adipate/hexamethylene Aliphatic polyamides such as diammonium adipate/hexamethylene diammonium sebacate copolymer (nylon 6/66/610), polyhexamethylene isophthalamide, polyhexamethylene terephthalamide, polymethaxylylene adipamide, hexamethylene isophthalate Amide/terephthalamide copolymers, aromatic polyamides such as poly-P-phenylene terephthalamide, poly-P-phenylene 3-4'diphenyl ether terephthalamide, amorphous polyamides, and these polyamide resins are methylenebenzylamine. , Those modified with aromatic amines such as metaxylylenediamine, and metaxylylenediammonium adipate. Alternatively, these terminal-modified polyamide-based resins may be used, and the terminal-modified polyamide-based resin is preferable.

<Other additives>
The EVOH resin composition of the present invention is generally added to the EVOH resin composition in a range that does not impair the effects of the present invention (for example, usually 10% by weight or less, preferably 5% by weight or less of the EVOH resin composition). Additives to be blended, for example, heat stabilizers, antioxidants, antistatic agents, colorants, UV absorbers, lubricants (for example, saturated aliphatic amides (for example, stearic acid amides), unsaturated fatty acid amides (for example, Oleic acid amide, etc.), bis fatty acid amide (eg, ethylene bisstearic acid amide, etc.), low molecular weight polyolefin (eg, low molecular weight polyethylene having a molecular weight of about 500 to 10000, or low molecular weight polypropylene), plasticizer (eg, ethylene) Aliphatic polyhydric alcohols such as glycol, glycerin, and hexanediol), light stabilizers, surfactants, antibacterial agents, desiccants, insoluble inorganic salts (eg, hydrotalcite), fillers (eg, inorganic fillers, etc.) ), an anti-blocking agent, a flame retardant, a cross-linking agent, a foaming agent, a crystal nucleating agent, an antifogging agent, an additive for biodegradation, a silane coupling agent, an oxygen absorber, phosphoric acid and/or a salt thereof, a conjugated polyene compound, Known additives such as an endiol group-containing substance (for example, phenols such as propyl gallate) and an aldehyde compound (for example, unsaturated aldehydes such as crotonaldehyde) may be contained. These may be used alone or in combination of two or more.

Specific examples of the phosphoric acid and/or its salt include, for example, phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate, phosphoric acid. Examples thereof include calcium monohydrogen, calcium dihydrogen phosphate, tricalcium phosphate, magnesium phosphate, magnesium hydrogen phosphate, magnesium dihydrogen phosphate, zinc hydrogen phosphate, barium hydrogen phosphate, and manganese hydrogen phosphate. These can be used alone or in combination of two or more. Among them, phosphoric acid, sodium dihydrogen phosphate, potassium dihydrogen phosphate, calcium dihydrogen phosphate, magnesium dihydrogen phosphate, zinc hydrogen phosphate are preferable, and phosphoric acid and sodium dihydrogen phosphate are particularly preferable. , Calcium dihydrogen phosphate and magnesium dihydrogen phosphate, and phosphoric acid is particularly preferable.

The phosphorus content of the phosphoric acid and/or its salt is EVOH (A), acetic acid and/or its salt (B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal salt (D), Normally, the content of cinnamic acid and/or its salt (E), phosphoric acid and/or its salt is preferably 900 ppm or less, more preferably 0.01 to 700 ppm, and even more preferably 0.1 ppm. ~500 ppm, particularly preferably 1-300 ppm.

The conjugated polyene compound has 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 bond. Is a compound having The conjugated polyene compound is a conjugated diene having a structure in which two carbon-carbon double bonds and one carbon-carbon single bond are alternately connected, three carbon-carbon double bonds and two carbon- A conjugated triene having a structure in which carbon single bonds are alternately connected, or a conjugated polyene compound having a structure in which a larger number of carbon-carbon double bonds and carbon-carbon single bonds are alternately connected may be used. .. However, if the number of conjugated carbon-carbon double bonds is 8 or more, the molded product may be colored by the color of the conjugated polyene compound itself, so that the number of conjugated carbon-carbon double bonds is 7 or less. It is preferably a polyene. Further, the above conjugated double bonds composed of two or more carbon-carbon double bonds may not be conjugated with each other, and a plurality of sets may be present in one molecule. For example, a compound having three conjugated trienes in the same molecule, such as tung oil, is also included in the conjugated polyene compound.

Specific examples of the conjugated polyene compound include a conjugated diene compound having two carbon-carbon double bonds such as isoprene, myrcene, farnesene, sembrene, sorbic acid, sorbic acid ester, sorbate, and abietic acid; Conjugated triene compounds having 3 carbon-carbon double bonds such as 5-hexatriene, 2,4,6-octatriene-1-carboxylic acid, eleostearic acid, tung oil, cholecalciferol; cyclooctatetraene, Examples thereof include conjugated polyene compounds having 4 or more carbon-carbon double bonds such as 2,4,6,8-decatetraene-1-carboxylic acid, retinol and retinoic acid. These conjugated polyene compounds may be used alone or in combination of two or more.

The content of the conjugated polyene compound is EVOH (A), acetic acid and/or its salt (B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal salt (D), cinnamic acid and/or its salt ( E), usually 0.01 to 10000 ppm, preferably 0.1 to 1000 ppm, particularly preferably 0.5 to 500 ppm, based on the total amount of the conjugated polyene compound.

The heat stabilizer, for the purpose of improving various physical properties such as heat stability during melt molding, for example, organic acids such as propionic acid, butyric acid, lauric acid, stearic acid, oleic acid, behenic acid (however, the above When an organic acid is used as the aliphatic carboxylic acid (C), it is not included in the heat stabilizer.), or alkali metal salts (sodium, potassium, etc.), alkaline earth metal salts (calcium, magnesium, etc.) of the above organic acids. ) And the like. These can be used alone or in combination of two or more.

<Method for producing EVOH resin composition>
The method for producing the EVOH resin composition of the present invention is not particularly limited, and examples thereof include the methods shown in (I) to (IV) below.
(I) Acetate and/or salt thereof (B), aliphatic carboxylic acid (C), metal salt of aliphatic carboxylic acid (D), cinnamic acid and/or salt thereof (E) on pellets of EVOH (A) A method of blending at least one selected from the group in a predetermined ratio and dry blending (dry blending method).
(II) EVOH (A) pellets consisting of acetic acid and/or its salt (B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal salt (D), cinnamic acid and/or its salt (E) A method of immersing the pellet in a solution containing at least one selected from the group and then drying the pellet (immersion method).
(III) From acetic acid and/or its salt (B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal salt (D), cinnamic acid and/or its salt (E) during melt kneading of EVOH (A) A method of blending at least one selected from the group consisting of the following, and then producing pellets (melt kneading method).
(IV) Acetic acid and/or its salt (B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal salt (D), cinnamic acid and/or its salt (E) in a solution containing EVOH (A) A method of adding at least one selected from the group consisting of and mixing, and then removing the solvent in the solution (solution mixing method).

Among them, acetic acid and/or salt thereof (B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal salt (D), cinnamic acid and/or salt thereof are added to pellets of EVOH (A) of (I). The method of blending at least one selected from the group consisting of (E) at a predetermined ratio and dry blending (dry blending method) is practical in terms of productivity and economical efficiency, and is industrially preferable. The above methods may be used in combination. Also, when the above-mentioned other additives are blended, the EVOH resin composition containing the other additives can be obtained by following the methods (I) to (IV).

As a means for dry blending in the above method (I), for example, a known mixing device such as a rocking mixer, a ribbon blender or a line mixer can be used.

In the dry blending in the above method (I), acetic acid and/or its salt (B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal salt (D), cinnamic acid and/or its salt (E) In order to improve the adhesion of at least one component selected from the group consisting of, the EVOH (A) pellets have a water content of 0.1 to 5% by weight (further 0.5 to 4% by weight, particularly 0.5 to 4% by weight). Is preferably 1 to 3% by weight). When the water content is too low, acetic acid and/or its salt (B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal salt (D) ), cinnamic acid and/or a salt thereof (E), at least one selected from the group tends to fall off, and the adhesion distribution tends to be uneven. On the contrary, when it is too large, it is selected from the group consisting of acetic acid and/or its salt (B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal salt (D), cinnamic acid and/or its salt (E). At least one kind of agglomerate tends to be non-uniform in the adhesion distribution.

The water content of the EVOH (A) pellets referred to here is measured and calculated by the following method.
[Measurement method of water content]
EVOH (A) pellets were weighed by an electronic balance (W1: unit g), placed in a hot air oven type dryer maintained at 150° C., dried for 5 hours, and then allowed to cool in a desiccator for 30 minutes. After that, the weight is similarly weighed (W2: unit g) and calculated from the following formula.
[Formula] Moisture content (%)={(W1-W2)/W1}×100

Further, in the above methods (I) and (II), acetic acid and/or a salt thereof (B), an aliphatic carboxylic acid (C), an aliphatic carboxylic acid metal salt (D) is provided outside the EVOH (A) pellets. A pellet having at least one component selected from the group consisting of cinnamic acid and/or its salt (E) is obtained.

As the means for melt kneading in the above method (III), for example, a known melt kneading device such as a kneader, a ruder, an extruder, a mixing roll, a Banbury mixer, a plastomill can be used, and usually 150 to It is preferable to melt-knead at 300° C. (further 180 to 280° C.) for about 1 to 20 minutes, and it is industrially advantageous to use a single-screw or twin-screw extruder to obtain pellets easily. If necessary, it is also preferable to provide a vent suction device, a gear pump device, a screen device and the like. In particular, in order to remove water and by-products (pyrolytic low molecular weight substances, etc.), one or more vent holes are provided in the extruder to suck under reduced pressure, and to prevent oxygen from mixing into the extruder. For this purpose, by continuously supplying an inert gas such as nitrogen into the hopper, it is possible to obtain an EVOH resin composition of excellent quality in which thermal coloring and thermal deterioration are reduced.

Further, the method of supply to a melt-kneading device such as an extruder is not particularly limited, and 1) EVOH (A), acetic acid and/or its salt (B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal Method of dry blending salt (D), cinnamic acid and/or its salt (E), boric acid and/or its salt (F), and supplying them to the extruder at once, 2) EVOH (A) is extruder Acetic acid and/or salt thereof (B), aliphatic carboxylic acid (C), metal salt of aliphatic carboxylic acid (D), cinnamic acid and/or salt thereof (E) which are solid after being supplied to and melted in , Boric acid and/or its salt (F) are supplied (solid side feed method), 3) EVOH (A) is supplied to an extruder and melted, and then acetic acid and/or its salt in a molten state ( B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal salt (D), cinnamic acid and/or its salt (E), boric acid and/or its salt (F) (melt side feed) Method) and the like, but among them, the method 1) is practical in terms of the simplicity of the apparatus, the cost of the blended product, and the like.

As a method for producing pellets after melt-kneading, known methods can be used, and examples thereof include a strand cutting method and a hot cutting method (in-air cutting method, underwater cutting method). From the viewpoint of industrial productivity, the strand cut method is preferable.

The solvent used in the solution mixing method in the above method (IV) may be a known good EVOH solvent, typically a mixed solvent of water and an aliphatic alcohol having 1 to 4 carbon atoms, A mixed solvent of water and methanol is preferable. Upon dissolution, heating and pressurization can be arbitrarily performed, and the concentration is also arbitrary. Acetate and/or its salt (B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal salt (D), cinnamic acid and/or its salt (E), in a solution or paste in which EVOH (A) is dissolved. Boric acid and/or its salt (F) may be blended. At this time, acetic acid and/or its salt (B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal salt (D), cinnamic acid and/or its salt (E), boric acid and/or its salt ( F) can be blended in the state of solid, solution, dispersion or the like.
After blending, the EVOH resin composition solution or paste that is uniformly stirred is pelletized by the above-described known method. From the viewpoint of industrial productivity, the underwater cut method is preferable. The obtained pellets are dried by a known method.

The pellet may have any shape such as a sphere, an oval, a cylinder, a cube, or a rectangular parallelepiped. Usually, it has an oval shape or a cylindrical shape, and the size of the oval shape is usually 1 to 6 mm, preferably 2 to 5 mm, and the major axis is from the viewpoint of convenience when used as a molding material later. Is usually 1 to 6 mm, preferably 2 to 5 mm. In the case of a cylindrical shape, the diameter of the bottom surface is usually 1 to 6 mm, preferably 2 to 5 mm, and the length is usually 1 to 6 mm, preferably 2 to 5 mm.

Thus, the EVOH resin composition of the present invention can be obtained.

<Multilayer structure>
The multilayer structure of the present invention has at least one layer composed of the EVOH resin composition of the present invention. The layer made of the EVOH resin composition of the present invention (hereinafter, simply referred to as “EVOH resin composition layer”) may be laminated with another base material to further increase strength and impart other functions. it can.

As the other base material, a thermoplastic resin other than EVOH (hereinafter referred to as "other base material resin") is preferably used.

Examples of the other base resin include linear low density polyethylene, low density polyethylene, ultra low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-propylene (block and random) copolymer, ethylene-α. -Polyethylene resin such as olefin (C4-20 α-olefin) copolymer, polypropylene, polypropylene, polypropylene resin such as propylene-α-olefin (C4-20 α-olefin) copolymer, polybutene (Unmodified) polyolefin resins such as polypentene and polycyclic olefin resins (polymers having a cyclic olefin structure in at least one of the main chain and side chains), and these polyolefins with unsaturated carboxylic acids or their esters. Polyolefin resin in a broad sense including modified olefin resin such as graft-modified unsaturated carboxylic acid modified polyolefin resin, ionomer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer Combined, polyester resin, polyamide resin (including copolyamide), polyvinyl chloride, polyvinylidene chloride, acrylic resin, polystyrene resin, vinyl ester resin, polyester elastomer, polyurethane elastomer, chlorinated polyethylene, chlorinated Examples thereof include halogenated polyolefin such as polypropylene, aromatic or aliphatic polyketones, and the like.

Of these, in consideration of hydrophobicity, hydrophobic resins such as polyamide-based resins, polyolefin-based resins, polyester-based resins and polystyrene-based resins are preferred, and more preferably polyethylene-based resins, polypropylene-based resins, polycyclic olefins. Resins and polyolefin resins such as unsaturated carboxylic acid-modified polyolefin resins, and the like, and particularly preferably polyolefin resins.

The α-olefin of the polyolefin-based resin may be a plant-derived α-olefin derived from bioethanol, or a non-plant-derived α-olefin, that is, a petroleum-derived α-olefin. May be used. Since a wide variety of petroleum-derived α-olefins are available, the physical properties and the like of the polyolefin resin can be easily adjusted by producing them using these. By using the plant-derived α-olefin, the degree of biomass of the final product can be further increased and the load on the environment can be reduced.

As a method for producing plant-derived ethylene and plant-derived α-olefins, sugar solution and starch obtained from plants such as sugar cane, corn and sweet potato are fermented by microorganisms such as yeast to produce bioethanol according to a conventional method. Then, this is heated in the presence of a catalyst, and plant-derived ethylene and plant-derived α-olefin (1-butene, 1-hexene, etc.) can be obtained by an intramolecular dehydration reaction or the like. Then, using the obtained plant-derived ethylene and plant-derived α-olefin, a plant-derived polyethylene resin can be produced in the same manner as the production of a petroleum-derived polyethylene resin.

The method for producing plant-derived ethylene, plant-derived α-olefin, and plant-derived polyethylene-based resin is described in detail, for example, in Japanese Patent Publication No. 2011-506628. Examples of the plant-derived polyethylene-based resin preferably used in the present invention include Green PE manufactured by Braskem SA.

In the layer structure of the multilayer structure of the present invention, the EVOH resin composition layer of the present invention is a (a1, a2,...) And the other base resin layers are b (b1, b2,...). In this case, a/b, b/a/b, a1/a2, a/b/a, a1/a2/b, a/b1/b2, a1/a2/a3, b2/b1/a/b1/b2, Any combination of b1/b2/a1/a2/a3/b3/b4, b2/b1/a1/b1/a1/b1/b2, etc. is possible. Further, even if the constitution of the layer laminated in one laminating direction and the constitution of the layer laminated in the other are the same (symmetric) with respect to an arbitrary EVOH resin composition layer (a), They may be different from each other (asymmetric). Furthermore, even if the thickness of the layer laminated in one laminating direction and the thickness of the layer laminated in the other are the same (symmetric) with respect to an arbitrary EVOH resin composition layer (a), They may be different from each other (asymmetric).
In the above layer structure, an adhesive resin layer may be interposed between the respective layers, if necessary. In the case of a multi-layer structure having another base resin layer (that is, a thermoplastic resin layer other than EVOH) on at least one surface of the EVOH resin composition layer of the present invention via an adhesive resin layer, The effect of tends to be obtained more effectively.
Further, the EVOH resin composition of the present invention and other base resin or adhesiveness with other base resin, which is obtained by re-melt molding of edges and defective products generated in the process of manufacturing the above-mentioned multilayer structure When the recycled layer containing a mixture of resins is R, b/R/a, a1/R/a2, b1/R/a/b2, b1/R1/a/R2/b2, b1/R1/b2/a1 It is also possible to use /a2/a3/b3/R2/b4, b1/a1/R/a2/b2, b1/R1/a1/R2/a2/R3/b2, etc. The total number of layers of the multilayer structure of the present invention is generally 2 to 15 layers, preferably 3 to 10 layers.

As the layer structure of the multilayer structure in the multilayer structure of the present invention, preferably, the EVOH resin composition layer of the present invention is included as an intermediate layer, and other base resin layers are provided as both outer layers of the intermediate layer. A multilayer structure having a unit of the multilayer structure (b/a/b or b/adhesive resin layer/a/adhesive resin layer/b) as a basic unit and having this basic unit as at least a structural unit is preferable.

As the adhesive resin that is the material for forming the adhesive resin layer, a known adhesive resin can be used, and may be appropriately selected depending on the type of the thermoplastic resin used for the other base resin layer. Typically, a modified polyolefin polymer containing a carboxy group obtained by chemically bonding an unsaturated carboxylic acid or an anhydride thereof to a polyolefin resin by an addition reaction or a graft reaction can be mentioned. For example, maleic anhydride graft modified polyethylene, maleic anhydride graft modified polypropylene, maleic anhydride graft modified ethylene-propylene (block and random) copolymer, maleic anhydride graft modified ethylene-ethyl acrylate copolymer, maleic anhydride graft Examples include modified ethylene-vinyl acetate copolymers, maleic anhydride-modified polycyclic olefin-based resins, maleic anhydride graft-modified polyolefin-based resins, and the like, and these can be used alone or in combination of two or more.

At this time, the content of the unsaturated carboxylic acid or the anhydride thereof is usually 0.001 to 3% by weight, preferably 0.01 to 1% by weight, particularly preferably 0, based on the total amount of the adhesive resin. 0.03 to 0.5% by weight. If the amount of modification in the modified product is small, the adhesiveness tends to be insufficient, and conversely, if it is large, a cross-linking reaction occurs and the moldability tends to deteriorate.
It is also possible to blend EVOH (A), other EVOH, a rubber/elastomer component such as polyisobutylene, ethylene-propylene rubber, and a resin of a polyolefin-based resin layer with these adhesive resins. In particular, it is possible to blend a polyolefin resin different from the base polyolefin resin of the adhesive resin.

The acetic acid and/or salt thereof used in the present invention is added to the other base resin and the adhesive resin layer within the range that does not impair the gist of the present invention (for example, 30 wt% or less, preferably 10 wt% or less). (B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal salt (D), cinnamic acid and/or its salt (E), boric acid and/or its salt (F), and other conventionally known plastics Agents (for example, ethylene glycol, glycerin, hexanediol, etc.), fillers, clay (for example, montmorillonite, etc.), colorants, antioxidants, antistatic agents, lubricants (for example, alkali metal salts of higher fatty acids having 10 to 30 carbon atoms) , Alkaline earth metal salts, higher fatty acid esters (eg, higher fatty acid methyl ester, isopropyl ester, butyl ester, octyl ester, etc.), higher fatty acid amides (eg, stearic acid amide, behenic acid amide, etc., saturated aliphatic amides, Unsaturated fatty acid amides such as oleic acid amide and erucic acid amide, bis fatty acid amides such as ethylenebisstearic acid amide, ethylenebisoleic acid amide, ethylenebiserucic acid amide, and ethylenebislauric acid amide), low molecular weight polyolefins (eg, , Low molecular weight polyethylene having a molecular weight of about 500 to 10,000, or low molecular weight polypropylene)), a fluorinated ethylene resin, a nucleating agent, an antiblocking agent, an ultraviolet absorber, a wax, and the like. These can be used alone or in combination of two or more.

It is also preferable to blend at least one of the aliphatic carboxylic acid (C) and the aliphatic carboxylic acid metal salt (D) in the present invention with the resin used in the adhesive resin layer. In particular, when the adhesive resin layer adjacent to the EVOH resin composition layer of the present invention contains an aliphatic carboxylic acid (C) or an aliphatic carboxylic acid metal salt (D), a multilayer structure having further excellent impact resistance Is obtained.

When the EVOH resin composition of the present invention is laminated with another base resin to produce a multilayer structure (including the case where an adhesive resin layer is interposed), the lamination method can be performed by a known method. .. For example, a method of melt extrusion laminating another base resin on a film, a sheet or the like made of the EVOH resin composition of the present invention, and conversely a method of melt extrusion laminating the EVOH resin composition of the present invention on another base resin, A method of co-extruding the EVOH resin composition of the present invention and another base resin, a film (layer) and another base resin (layer) made of the EVOH resin composition of the present invention are prepared, respectively A method of dry laminating using a known adhesive such as a titanium compound, an isocyanate compound, a polyester compound, or a polyurethane compound, or a solution of the EVOH resin composition of the present invention is applied onto another base resin, and then a solvent is applied. A method of removing it may be mentioned. Among these, the coextrusion method is preferable in consideration of cost and environment.

The multilayer structure can be used as it is in various shapes, but if necessary, (heated) stretching treatment is performed. The stretching treatment may be uniaxial stretching or biaxial stretching, and in the case of biaxial stretching, it may be simultaneous stretching or sequential stretching. As the stretching method, a roll stretching method, a tenter stretching method, a tubular stretching method, a stretching blow method, a vacuum pressure forming method, or the like having a high stretching ratio can be employed. The stretching temperature is usually selected from the range of 40 to 170°C, preferably about 60 to 160°C. If the stretching temperature is too low, the stretchability tends to be poor, and if it is too high, it tends to be difficult to maintain a stable stretched state.

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

When the multilayer stretched film obtained by using the EVOH resin composition of the present invention is used as a shrink film, the above heat setting is not performed in order to impart heat shrinkability, for example, after stretching. Processing such as applying cold air to the film to fix and cool it may be performed.

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

The thickness of the multilayer structure (including stretched ones) of the present invention, and further the thickness of the resin composition layer, the other base resin layer and the adhesive resin layer constituting the multilayer structure are the layer constitution and the base resin. It is appropriately set depending on the type of the adhesive, the type of the adhesive resin, the use, the packaging form, the required physical properties, and the like.

The thickness of the multilayer structure of the present invention (including stretched ones) is usually 10 to 5000 μm, preferably 30 to 3000 μm, and particularly preferably 50 to 2000 μm. If the total thickness of the multilayer structure is too thin, the gas barrier property tends to be reduced. Further, when the total thickness of the multilayer structure is too thick, the gas barrier property becomes an excessive performance and an unnecessary raw material is used, which is not economically preferable. The EVOH resin composition layer of the present invention in the above-mentioned multilayer structure is usually 1 to 500 μm, preferably 3 to 300 μm, particularly preferably 5 to 200 μm, and the other base resin layers are usually 5 to 3000 μm, preferably Is 10 to 2000 μm, particularly preferably 20 to 1000 μm, and the adhesive resin layer is usually 0.5 to 250 μm, preferably 1 to 150 μm, and particularly preferably 3 to 100 μm. Note that the above numerical values are values obtained by summing the thicknesses of the same kind of layers when at least one kind of the EVOH resin composition layer, the adhesive resin layer, and the other base resin layer is present in two or more layers. Is.

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

The film obtained as described above, a bag and a cup made of a stretched film, a tray, a tube, a container made of a bottle or the like, a general food, mayonnaise, seasonings such as dressing, miso, etc. It is useful as a container for various packaging materials such as fermented foods, oil and fat foods such as salad oil, beverages, cosmetics, pharmaceuticals and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples shown in the following table, but the present invention is not limited to the following Examples as long as the gist thereof is not exceeded.

[Example 1]
[Production of EVOH resin composition]
As EVOH (A), EVOH (a1) [content of ethylene structural unit: 29 mol%, saponification degree: 99.7 mol%, MFR: 3.8 g/10 min (210° C., load: 2160 g) ethylene-vinyl alcohol copolymer weight Combined], and EVOH (a1) pellets containing sodium acetate (b1) as acetic acid and/or its salt (B) were used. Further, stearic acid (c1) as the aliphatic carboxylic acid (C), zinc stearate (d1) as the aliphatic carboxylic acid metal salt (D), and trans-cinnamic acid (e1) as the cinnamic acid and/or its salt (E). ), boric acid and/or boric acid (f1) was used as its salt (F).
As the content of each component, the content of sodium acetate (b1) is EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc stearate (d1), trans-cinnamic acid (e1). 432 ppm in terms of acetate ion is used with respect to the total amount of stearic acid (c1) of EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc stearate (d1), trans-cinnamic acid (e1). Using 2.4 ppm in terms of carboxylate ion based on the total content, zinc stearate (d1) is EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc stearate (d1), trans- Using 50 ppm in terms of metal ion based on the total content of cinnamic acid (e1), trans-cinnamic acid (e1) is EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc stearate (d1). ), 150 ppm in terms of cinnamic acid ion based on the total content of trans-cinnamic acid (e1), boric acid (f1) is EVOH (a1), sodium acetate (b1), stearic acid (c1), stearic acid 59.45 ppm in terms of boron was used with respect to the total content of zinc (d1), trans-cinnamic acid (e1) and boric acid (f1). The EVOH resin composition of the present invention was manufactured by dry blending EVOH (a1) pellets, stearic acid (c1), zinc stearate (d1), trans-cinnamic acid (e1) and boric acid (f1) all together. ..

[Manufacture of multilayer structure]
The EVOH resin composition prepared above and the linear low-density polyethylene (LLDPE) [“UF240” manufactured by Nippon Polyethylene Co., Ltd., MFR 2.1 g/10 min (190° C.) were used in a 3 type 5 layer multi-layer coextrusion cast film forming apparatus. , Load 2160 g)], an adhesive resin (“PLEXAR PX3236” manufactured by Lyondell Basell, MFR 2.0 g/10 min [190° C., load 2160 g]), and LLDPE layer/adhesion by multi-layer coextrusion molding under the following conditions: A multi-layered structure (film) having a three-kind five-layer structure of a conductive resin layer/EVOH resin composition layer/adhesive resin layer/LLDPE layer was obtained. The thickness (μm) of each layer of the multilayer structure was 37.5/5/15/5/37.5. The die temperature of the molding apparatus was set to 210° C. in all cases.
(Multilayer coextrusion conditions)
・Middle layer extruder (EVOH resin composition): 40 mmφ single screw extruder (barrel temperature: 210° C.)
・Upper and lower layer extruder (LLDPE): 40 mmφ single screw extruder (barrel temperature: 210°C)
・Middle and upper layer extruder (adhesive resin): 32 mmφ single screw extruder (barrel temperature: 210°C)
・Die: 3 types 5 layers feed block type T-die (die temperature: 210°C)
・Take-off speed: 9.0 m/min ・Roll temperature: 80°C

The EVOH resin composition obtained above was subjected to the following color stability evaluation test and extensional viscosity evaluation test, and the multilayer structure obtained above was subjected to the impact strength evaluation test described below. The adhesive strength evaluation test and the light resistance evaluation test were performed.

<Evaluation of color stability of EVOH resin composition>
5 g of the EVOH resin composition produced above was placed in a 30 mmφ aluminum cup (Dispodinish PP-724 manufactured by As One Co., Ltd.) and left standing at 210° C. for 2 hours in an air atmosphere, and the color tone was evaluated. The color tone evaluation was performed based on the following device and evaluation method.
-Device used: Visual Analyzer IRISVA400 (manufactured by Alpha Mos Japan)
・Data analysis software: Alpha Soft V14.3
-Objective lens: 25 mm (Basler)
・Illumination mode: Vertical illumination ・Evaluation method: The sample for color tone evaluation is set on the tray inside the chamber of the above visual analyzer, and a plane image of the entire sample for color tone evaluation is taken with a CCD camera, and then data analysis software is used. Image processing was performed to evaluate the color pattern of the sample. Among the obtained color patterns, the color tone stability of the EVOH resin composition was evaluated from the lightness (L*) of the color (main color) having the highest abundance ratio. The color stability means that the higher the value, the better the color stability, and conversely, the lower the value, the poorer the color stability. The results are shown in Table 1-2.

<Evaluation of extensional viscosity (Pa·s) of EVOH resin composition>
The elongation viscosity (Pa·s) at 210° C. and 100 S ⁻¹ of the EVOH resin composition produced above was measured using a capillary rheometer using the Cogswell formula [Polymer Engineering Science, Volume 12, pages 64-73 ( 1972)], that is, based on the following formulas (5) to (7), evaluation was performed by performing measurement under the following conditions. The results are shown in Table 1-2.
(Cogswell type)
η _e =[9(n+1) ² P ₀ ² ]/[32 η _s (dγ/dt) ² ]... Equation (5)
dε/dt=4σ _s (dγ/dt)/[3(n+1)P ₀ ]... Expression (6)
σ _s =k(dγ/dt) ⁿ (7)
η _e : elongational viscosity (Pa·s)
η _s : Shear viscosity (Pa·s)
dγ/dt: Shear strain rate (s ^-1 )
dε/dt: elongation strain rate (s ⁻¹ )
σ _s : Shear stress (Pa)
k, n: constant P ₀ : pressure loss (Pa)
(Conditions for measuring extensional viscosity)
Measuring device: RHEOGRAPH 20 manufactured by Gottfert
Measurement temperature: 210℃
Preheating time: 10 minutes Long die: length 10 mm, diameter 1 mm, inflow angle 180°
Short die: length 0.2mm, diameter 1mm, inflow angle 180°

<Impact strength of multilayer structure>
The impact strength (kgf·cm) of the multilayer structure produced above was evaluated using a YSS type film impact tester (Model 181 manufactured by Yasuda Seiki Seisakusho Co., Ltd.) in an atmosphere of 23° C. and 50% RH. The measurement was performed 10 times in total, and the average value was evaluated as the impact strength of the multilayer structure. The clamp inner diameter was 60 mm, the impact ball had a radius of 12.7 mm, and the pendulum lifting angle was 90°. The higher the numerical value of the impact strength of the multilayer structure, the better the impact strength, and the lower the value, the poorer the impact strength. The results are shown in Table 1-2.

<Adhesive strength of multilayer structure>
The adhesive strength (N/15 mm) between the EVOH resin composition layer and the adhesive resin layer in the multilayer structure produced above was evaluated by the following T-peel peel test. The measurement was performed 10 times in total, and the average value was evaluated as the adhesive strength of the multilayer structure. The higher the numerical value of the adhesive strength of the multilayer structure, the better the adhesive strength, and the lower the numerical value, the poorer the adhesive strength. The results are shown in Table 1-2.
(T-peel peel test condition)
・Device: Autograph AGS-H (manufactured by Shimadzu Corporation)
・Load cell: 500N
-Test method: T-peel method (T-shaped and peeled)
・Test piece size: width 15 mm
・Test speed: 300 mm/min

<Light resistance of multilayer structure>
The light resistance of the multilayer structure manufactured above was measured for transmittance (%) at a wavelength of 280 nm (ultraviolet region) using a spectrophotometer “UV2600” manufactured by Shimadzu Corporation. In addition, a reference multilayer structure was manufactured by the same procedure, and the transmittance (%) was measured in the same manner.

Then, the ultraviolet absorption increase rate (Z) was calculated using the following formula (8), and the light resistance of the multilayer structure was evaluated according to the following evaluation criteria. The light resistance of the multilayer structure means that the higher the value of the ultraviolet absorption increase rate (Z) is, the better the light resistance is, and the lower the value is, the poorer the light resistance is. The results are shown in Table 1-2.
A: UV absorption increase rate (Z)≧2
B: 1.5≦UV absorption increase rate (Z)<2
C: UV absorption increase rate (Z) <1.5

UV absorption increase rate (Z) [(UV transmittance of reference film)/(UV transmittance of multilayer structure of Example 1)] Equation (8)

[Example 2]
In Example 1, stearic acid (c1) was added to EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc stearate (d1), and the total content of trans-cinnamic acid (e1). An EVOH resin composition and a multilayer structure were produced in the same manner except that 0.7 ppm in terms of carboxylate ion was used. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 3]
In Example 1, stearic acid (c1) was added to EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc stearate (d1), and the total content of trans-cinnamic acid (e1). Use of 4.9 ppm in terms of carboxylate ion, zinc stearate (d1) containing EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc stearate (d1), trans-cinnamic acid (e1) An EVOH resin composition and a multilayer structure were produced in the same manner except that 100 ppm in terms of metal ion was used with respect to the total amount. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 4]
In Example 1, stearic acid (c1) was added to EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc stearate (d1), and the total content of trans-cinnamic acid (e1). Use of 9.7 ppm in terms of carboxylate ion, zinc stearate (d1) containing EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc stearate (d1), trans-cinnamic acid (e1) An EVOH resin composition and a multilayer structure were produced in the same manner except that 200 ppm was used in terms of metal ions based on the total amount. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 5]
In Example 1, caprylic acid (c2) was replaced with EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), trans-cinnamic acid (e1) instead of stearic acid (c1). 6.9 ppm in terms of carboxylate ion is used with respect to the total content of zinc stearate (d1) instead of zinc caprylate (d2) EVOH (a1), sodium acetate (b1), caprylic acid (c2) , Zinc caprylate (d2), trans-cinnamic acid (e1) content of 50 ppm in terms of metal ion, trans-cinnamic acid (e1) EVOH (a1), sodium acetate (b1), capryl The EVOH resin composition and the multilayer structure were prepared in the same manner except that 5 ppm of cinnamic acid ion was used based on the total content of the acid (c2), zinc caprylate (d2) and trans-cinnamic acid (e1). It was made. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 6]
In Example 5, trans-cinnamic acid (e1) was added to the total content of EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), and trans-cinnamic acid (e1). On the other hand, an EVOH resin composition and a multilayer structure were produced in the same manner except that 20 ppm of cinnamic acid ion was used. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 7]
In Example 5, trans-cinnamic acid (e1) was added to the total content of EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), and trans-cinnamic acid (e1). On the other hand, an EVOH resin composition and a multilayer structure were produced in the same manner except that 150 ppm in terms of cinnamic acid ion was used. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 8]
In Example 5, trans-cinnamic acid (e1) was added to the total content of EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), and trans-cinnamic acid (e1). On the other hand, an EVOH resin composition and a multilayer structure were produced in the same manner except that 1000 ppm of cinnamic acid ion was used. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 9]
In Example 5, trans-cinnamic acid (e1) was added to the total content of EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), and trans-cinnamic acid (e1). On the other hand, 150 ppm in terms of cinnamic acid ion is used, and boric acid (f1) is EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), trans-cinnamic acid (e1), boric acid. An EVOH resin composition and a multilayer structure were produced in the same manner except that 300 ppm in terms of boron was used with respect to the total content of (f1). The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 10]
In Example 5, trans-cinnamic acid (e1) was added to the total content of EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), and trans-cinnamic acid (e1). On the other hand, the content of caprylic acid (c2) is EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), trans-cinnamic acid (e1) using 150 ppm in terms of cinnamic acid ion 13.8 ppm in terms of carboxylate ion is used for EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), trans-cinnamic acid. An EVOH resin composition and a multilayer structure were produced in the same manner except that 100 ppm in terms of metal ion was used with respect to the total content of (e1). The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 11]
In Example 10, sodium acetate (b1) was added to the total content of EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), and trans-cinnamic acid (e1). Using 100 ppm in terms of acetate ion, boric acid (f1) is EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), trans-cinnamic acid (e1), boric acid (f1). The EVOH resin composition and the multilayer structure were produced in the same manner except that 13.7 ppm in terms of boron was used with respect to the total content of. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 12]
In Example 10, caprylic acid (c2) was added to EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2) and trans-cinnamic acid (e1) with respect to the total content. Using 27.6 ppm of carboxylate ion, zinc caprylate (e1) containing EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), trans-cinnamic acid (e1) An EVOH resin composition and a multilayer structure were produced in the same manner except that 200 ppm was used in terms of metal ions based on the total amount. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 13]
In Example 1, lauric acid (c3) was replaced with EVOH (a1), sodium acetate (b1), lauric acid (c3), zinc laurate (d3), trans-cinnamic acid (e1) instead of stearic acid (c1). 1.8 ppm in terms of carboxylate ion is used with respect to the sum of the total content of zinc stearate (d1), zinc laurate (d3) is EVOH (a1), sodium acetate (b1), and lauric acid (c3). EVOH resin composition and multilayer structure were prepared in the same manner except that 50 ppm in terms of metal ion was used with respect to the total content of zinc laurate (d3) and trans-cinnamic acid (e1). The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 14]
In Example 13, lauric acid (c3) was added to EVOH (a1), sodium acetate (b1), lauric acid (c3), zinc laurate (d3), trans-cinnamic acid (e1) based on the total content. Use of 3.6 ppm in terms of carboxylate ion, containing zinc laurate (d3) in EVOH (a1), sodium acetate (b1), lauric acid (c3), zinc laurate (d3), trans-cinnamic acid (e1) An EVOH resin composition and a multilayer structure were produced in the same manner except that 100 ppm in terms of metal ion was used with respect to the total amount. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 15]
In Example 13, lauric acid (c3) was added to EVOH (a1), sodium acetate (b1), lauric acid (c3), zinc laurate (d3), trans-cinnamic acid (e1) based on the total content. Using 7.1 ppm in terms of carboxylate ion, zinc laurate (d3) containing EVOH (a1), sodium acetate (b1), lauric acid (c3), zinc laurate (d3), trans-cinnamic acid (e1) An EVOH resin composition and a multilayer structure were produced in the same manner except that 200 ppm was used in terms of metal ions based on the total amount. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 16]
In Example 1, behenic acid (c4) was replaced with EVOH (a1), sodium acetate (b1), behenic acid (c4), zinc behenate (d4), trans-cinnamic acid (e1) in place of stearic acid (c1). 2.9 ppm in terms of carboxylate ion is used with respect to the total content of zinc behenate (d1) instead of zinc stearate (d4) EVOH (a1), sodium acetate (b1), behenic acid (c4) EVOH resin composition and multilayer structure were prepared in the same manner except that 50 ppm in terms of metal ion was used with respect to the total content of zinc behenate (d4) and trans-cinnamic acid (e1). The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 17]
In Example 7, caprylic acid (c2) was added to EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), trans-cinnamic acid (e1) with respect to the total content. An EVOH resin composition and a multilayer structure were prepared in the same manner except that 269 ppm of carboxylate ion was used. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Example 18]
In Example 13, lauric acid (c3) was added to EVOH (a1), sodium acetate (b1), lauric acid (c3), zinc laurate (d3), trans-cinnamic acid (e1) based on the total content. An EVOH resin composition and a multilayer structure were prepared in the same manner except that 355 ppm of carboxylate ion was used. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Comparative Example 1]
An EVOH resin composition and a multilayer structure were prepared in the same manner as in Example 7, except that trans-cinnamic acid (e1) was not used. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Comparative Example 2]
In Example 7, trans-cinnamic acid (e1) was added to the total content of EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), and trans-cinnamic acid (e1). On the other hand, an EVOH resin composition and a multi-layer structure were produced in the same manner except that cinnamic acid ion was used in an amount of 5000 ppm. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Comparative Example 3]
An EVOH resin composition and a multilayer structure were prepared in the same manner as in Example 7, except that caprylic acid (c2) and zinc caprylate (d2) were not used. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Comparative Example 4]
An EVOH resin composition and a multilayer structure were prepared in the same manner as in Example 7, except that sodium acetate (b1) and boric acid (f1) were not used. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Comparative Example 5]
In Example 7, caprylic acid (c2) was added to EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), trans-cinnamic acid (e1) with respect to the total content. Containing 82.8 ppm of carboxylate ion, zinc caprylate (d2) containing EVOH (a1), sodium acetate (b1), caprylic acid (c2), zinc caprylate (d2), trans-cinnamic acid (e1) An EVOH resin composition and a multilayer structure were produced in the same manner except that 600 ppm was used in terms of metal ions based on the total amount. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Comparative Example 6]
In Example 13, lauric acid (c3) was added to EVOH (a1), sodium acetate (b1), lauric acid (c3), zinc laurate (d3), trans-cinnamic acid (e1) based on the total content. Use of 21.4 ppm in terms of carboxylate ion, containing zinc laurate (d3) in EVOH (a1), sodium acetate (b1), lauric acid (c3), zinc laurate (d3), trans-cinnamic acid (e1) An EVOH resin composition and a multilayer structure were produced in the same manner except that 600 ppm was used in terms of metal ions based on the total amount. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Comparative Example 7]
In Example 1, stearic acid (c1) was added to EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc stearate (d1), and the total content of trans-cinnamic acid (e1). Using 29.2 ppm of carboxylate ion, zinc stearate (d1) containing EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc stearate (d1), trans-cinnamic acid (e1) An EVOH resin composition and a multilayer structure were produced in the same manner except that 600 ppm was used in terms of metal ions based on the total amount. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Comparative Example 8]
In Example 1, stearic acid (c1) was converted into EVOH (a1), sodium acetate (b1), stearic acid (c1), calcium stearate, trans-cinnamic acid (e1) based on the total amount of carboxylate ion conversion. Calcium stearate for EVOH (a1), sodium acetate (b1), stearic acid (c1), calcium stearate, trans-cinnamic acid (e1) is added to the total content of 50 ppm for metal ion conversion. The same procedure was followed except that the EVOH resin composition and the multilayer structure were produced. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Comparative Example 9]
In Example 1, stearic acid (c1) was added to EVOH (a1), sodium acetate (b1), stearic acid (c1), magnesium stearate, and trans-cinnamic acid (e1) with respect to the total content of carboxylate ion. Using 15.4 ppm in conversion, the content of EVOH (a1), sodium acetate (b1), stearic acid (c1), magnesium stearate, trans-cinnamic acid (e1) instead of zinc stearate (d1) is calcium stearate. Was carried out in the same manner except that 50 ppm in terms of metal ion was used with respect to the sum of the above, to prepare an EVOH resin composition and a multilayer structure. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Comparative Example 10]
In Example 1, stearic acid (c1) was added to EVOH (a1), sodium acetate (b1), stearic acid (c1), sodium stearate, and trans-cinnamic acid (e1) with respect to the total content of carboxylate ion. Using 3.3 ppm in conversion, the content of EVOH (a1), sodium acetate (b1), stearic acid (c1), sodium stearate, trans-cinnamic acid (e1) in place of zinc stearate (d1) is calcium stearate. Was carried out in the same manner except that 50 ppm in terms of metal ion was used with respect to the sum of the above, to prepare an EVOH resin composition and a multilayer structure. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Comparative Example 11]
In Example 1, stearic acid (c1) was added to EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc stearate (d1), and the total content of trans-cinnamic acid (e1). An EVOH resin composition and a multilayer structure were prepared in the same manner except that 483.6 ppm of carboxylate ion was used. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Comparative Example 12]
In Example 1, stearic acid (c1) was added to EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc stearate (d1), and the total content of trans-cinnamic acid (e1). An EVOH resin composition and a multilayer structure were produced in the same manner except that 0.4 ppm in terms of carboxylate ion was used. The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Comparative Example 13]
In Example 1, zinc gluconate trihydrate was replaced with EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc gluconate trihydrate, trans-cinnamic acid instead of zinc stearate (d1). An EVOH resin composition and a multilayer structure were produced in the same manner except that 50 ppm in terms of metal ion was used with respect to the total content of the acid (e1). The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

[Comparative Example 14]
In Example 1, zinc gluconate dihydrate was used instead of zinc stearate (d1) in EVOH (a1), sodium acetate (b1), stearic acid (c1), zinc gluconate dihydrate, and trans-cinnamon. An EVOH resin composition and a multilayer structure were produced in the same manner except that 50 ppm in terms of metal ion was used with respect to the total content of the acid (e1). The EVOH resin composition and the multilayer structure thus obtained were evaluated in the same manner as in Example 1.

Comparative Example 1 containing no cinnamic acid and/or its salt (E) was inferior in light resistance.
Further, Comparative Example 2 which does not satisfy the formula (1) defined by the present invention had low impact strength, adhesive strength and color stability.
Further, in Comparative Example 3 containing no aliphatic carboxylic acid metal salt (D), the impact strength was 14.50 (kgf·cm), while the aliphatic carboxylic acid metal salt (D) was contained and acetic acid In Comparative Example 4 containing no and/or salt (B) thereof, the impact strength was improved to 17.19 (kgf·cm). However, the adhesive strength decreased to 3.08 (N/15 mm).
Further, in Comparative Examples 4 to 7, which did not satisfy the formula (2) defined in the present invention, the adhesive strength was low. In Comparative Examples 11 and 12 that did not satisfy the formula (3) defined in the present invention, the impact strength was low.
Furthermore, even in Comparative Examples 8 to 10 in which the metal species of the aliphatic carboxylic acid metal salt (D) is not one type selected from the elements belonging to the 4th period d block of the long periodic table, the impact strength is low. It was
Then, in Comparative Examples 13 and 14 in which the anionic species of the aliphatic carboxylic acid (C) and the aliphatic carboxylic acid metal salt (D) were not the same, the impact strength and the adhesive strength were low.

The EVOH resin compositions (Examples 1 to 18) having the characteristic constitution of the present invention were excellent in impact strength and light resistance, but did not deteriorate in adhesive strength and showed excellent values. Further, the stability of color tone was not deteriorated. Moreover, it was also excellent in light resistance.

A package was manufactured using the multilayer structure of each example obtained above. The resulting packages were all excellent in impact resistance and adhesive strength.

Although specific embodiments of the present invention have been shown in the above embodiments, the above embodiments are merely examples and should not be construed as limiting. Various modifications apparent to those skilled in the art are intended to be within the scope of the present invention.

The EVOH resin composition of the present invention is excellent in impact resistance and adhesive strength. Therefore, the multi-layer structure containing a layer composed of the EVOH resin composition, in addition to general foods, mayonnaise, seasonings such as dressings, fermented foods such as miso, oil and fat foods such as salad oil, beverages, cosmetics, pharmaceuticals. It is useful as a raw material for various packaging material containers such as.

Claims (10)

Ethylene-vinyl alcohol copolymer (A), acetic acid and/or its salt (B), aliphatic carboxylic acid (C) other than acetic acid, and aliphatic carboxylic acid which is a metal salt of the above aliphatic carboxylic acid (C). A resin composition containing a metal salt (D), cinnamic acid and/or a salt thereof (E), wherein the metal species of the aliphatic carboxylic acid metal salt (D) is a long period type periodic table fourth period d. At least one selected from the elements belonging to the block, the acetic acid and/or salt thereof (B), the aliphatic carboxylic acid (C), the aliphatic carboxylic acid metal salt (D), the cinnamic acid and/or An ethylene-vinyl alcohol-based copolymer resin composition, wherein various contents of the salt (E) satisfy the following formulas (1) to (3) on a weight basis.
[Formula] 0.015 ≤ ((D) metal ion equivalent content/(E) cinnamic acid ion equivalent content) ≤ 50 (1)
[Formula] 0.001 ≤ ((D) metal ion-equivalent content/(B) acetate ion-equivalent content) ≤ 1.30 (2)
[Formula] 0.11≦((D) metal ion converted content/(C) carboxylate ion converted content)≦100 (3) The content of the cinnamic acid and/or its salt (E) in terms of cinnamic acid ion is such that the ethylene-vinyl alcohol copolymer (A), the acetic acid and/or its salt (B), and the aliphatic carvone are The content of the acid (C), the aliphatic carboxylic acid metal salt (D), the cinnamic acid and/or its salt (E) is 1 to 1000 ppm with respect to the total content. The ethylene-vinyl alcohol-based copolymer resin composition described. The content of the metal salt of aliphatic carboxylic acid (D) in terms of metal ion is such that the ethylene-vinyl alcohol copolymer (A), the acetic acid and/or its salt (B), the aliphatic carboxylic acid ( C), the aliphatic carboxylic acid metal salt (D), the cinnamic acid and/or its salt (E), relative to the total content, 1 to 500 ppm, characterized in that The ethylene-vinyl alcohol-based copolymer resin composition described. The content of the aliphatic carboxylic acid (C) in terms of carboxylic acid ions is such that the ethylene-vinyl alcohol copolymer (A), the acetic acid and/or its salt (B), the aliphatic carboxylic acid (C ), 0.001 to 450 ppm with respect to the total content of the aliphatic carboxylic acid metal salt (D), the cinnamic acid and/or its salt (E). The ethylene-vinyl alcohol-based copolymer resin composition according to any one of 1. The content of the acetic acid and/or its salt (B) in terms of acetate ions is such that the ethylene-vinyl alcohol copolymer (A), the acetic acid and/or its salt (B), and the aliphatic carboxylic acid ( C), the aliphatic carboxylic acid metal salt (D), and the total content of the cinnamic acid and/or its salt (E) are 10 to 2000 ppm, characterized in that The ethylene-vinyl alcohol-based copolymer resin composition according to any one of items. Content ratio of the cinnamic acid and/or its salt (E) in terms of cinnamic acid ion to the content of acetic acid and/or its salt (B) in terms of acetic acid ion (conversion of (E) to cinnamic acid ion) Content/(Acetic acid ion equivalent content of (B)) is 0.0001 to 10000 on a weight basis, ethylene-vinyl alcohol copolymer according to any one of claims 1 to 5, characterized in that Polymer resin composition. The extension viscosity at 210° C. and 100 S ⁻¹ of the ethylene-vinyl alcohol-based copolymer resin composition satisfies the following formula (4), wherein The ethylene-vinyl alcohol copolymer resin composition.
[Formula] 500≦extension viscosity [Pa·s]≦48000 (4) Furthermore, in the ethylene-vinyl alcohol copolymer resin composition containing boric acid and/or its salt (F), the boric acid and/or its salt (F) is the ethylene-vinyl alcohol-based copolymer Combined (A), acetic acid and/or salt thereof (B), aliphatic carboxylic acid (C), aliphatic carboxylic acid metal salt (D), cinnamic acid and/or salt thereof (E), boro The ethylene-vinyl according to any one of claims 1 to 7, wherein the content of the acid and/or its salt (F) is 0.001 to 500 ppm in terms of boron based on the total content. Alcohol-based copolymer resin composition. A multilayer structure having a layer formed of the ethylene-vinyl alcohol-based copolymer resin composition according to any one of claims 1 to 8. A package comprising the multilayer structure according to claim 9.