JP6706830B2 - Resin composition containing ethylene-vinyl alcohol copolymer, molded article and multilayer structure - Google Patents

Description

The present invention relates to a resin composition containing an ethylene-vinyl alcohol copolymer, a molded article, and a multilayer structure.

Packaging materials for food and drink in the form of films, sheets, bags, bottles, etc., packing materials for containers for sealing beverage bottles and crowns, sealing medicine bottles and lids, etc., medical infusion bag materials The tire tube material, the cosmetic packaging material, the pharmaceutical packaging material, the toothpaste packaging material, the shoe cushion material, and the like are required to have gas barrier properties and good mechanical properties.

For example, since packaging materials for food and drink, packaging materials for cosmetics, packaging materials for medicine, packaging materials for toothpaste, etc. are required to have good mechanical properties and high gas barrier properties, ethylene-vinyl alcohol copolymer A laminate having a gas barrier layer made of a coalesced or polyamide and a resin layer having good mechanical properties is widely used. NR (natural rubber) and IIR (butyl rubber) are generally used for the packing material for containers because good mechanical properties and gas barrier properties are required. Vinyl chloride is generally used for medical infusion bag materials because good mechanical properties and gas barrier properties are required. IIR is generally used for a tire tube material because a high gas barrier property and good mechanical properties are required.

However, a complicated vulcanization step is required after molding in order to exhibit good mechanical properties in a molded product using the NR or IIR. Further, in the packaging material for food and drink, the packaging material for cosmetics, the packaging material for pharmaceuticals, the packaging material for toothpaste, etc., the ethylene-vinyl alcohol copolymer or polyamide is excellent in gas barrier but mechanical properties are insufficient. Therefore, in order to supplement it, it is used in the form of a laminate with a resin layer having good mechanical properties, but as a result, it is accompanied by limitations and complications in the molding process. Since NR does not have a very high gas barrier property, it is disadvantageous in terms of long-term storability of contents when it is used as a packing material for containers and the like. In addition, since vinyl chloride contains a large amount of chlorine atoms, molded products such as medical infusion bag materials made from it may be harmful to the environment due to the generation of hydrogen chloride gas during incineration. Has been done.

Therefore, an ethylene-vinyl alcohol copolymer having excellent gas barrier properties is blended with a polyolefin resin, and the properties such as gas barrier properties, moldability, stretchability, and crack resistance obtained from both are utilized, and a blended product is studied. (Patent Document 1 [0002]).

Japanese Patent Laid-Open No. 5-255554

However, when the mixing ratio of the polyolefin resin with respect to the ethylene-vinyl alcohol copolymer is increased, the mechanical properties are improved, but the gas barrier property is sharply deteriorated. If the mixing ratio of EVOH is increased to improve the gas barrier property, There has been a problem that mechanical properties (tensile elongation at break) are lowered. Therefore, it has been found that there is room for improvement in the balance between the gas barrier property and the good mechanical properties of the molded product obtained from the resin composition. The present invention has been made under the circumstances described above, and an object of the present invention is to provide a resin composition that gives a molded article having an excellent balance between gas barrier properties and mechanical properties.

As a result of earnest studies to solve the above-mentioned problems, the present inventors have found that an ethylene-vinyl alcohol copolymer (A) (hereinafter, also referred to as “EVOH(A)”) and a polyolefin (B) (hereinafter, referred to as “B”). , And also referred to as “PO(B)”) and a modified polyolefin (C), wherein the ethylene-vinyl alcohol copolymer (A), the polyolefin (B) and the modified polyolefin (C) have a three-dimensional network structure. It was found that the above-mentioned problems can be solved by using a resin composition to be formed, and further research was carried out based on this finding to complete the present invention.

That is, the present invention is
[1] An ethylene-vinyl alcohol copolymer (A), a polyolefin (B) and a modified polyolefin (C) are contained, and the ethylene-vinyl alcohol copolymer (A), the polyolefin (B) and the modified polyolefin (C) are included. ) Form a three-dimensional network structure, a resin composition;
[2] When an arbitrary cross section of the resin composition is observed with a three-dimensional X-ray microscope, EVOH(A) and PO(B) in the resin composition are placed in a 200 μm×200 μm square arbitrarily selected on the cross section. ), the phase composed of the resin with the smaller content has a length in the longitudinal direction of 20 μm or more, and the ratio of the length in the longitudinal direction to the length in the lateral direction (lateral length/longitudinal length) is 0. When 5 or more phases of 5 or less are observed, and when an arbitrary cross section in the vertical direction of such a cross section is observed by a three-dimensional X-ray microscope, in a randomly selected 200 μm×200 μm square of the cross section in the vertical direction. In the resin composition, the phase composed of the resin phase having the smaller content of EVOH (A) and PO (B) has a length in the longitudinal direction of 20 μm or more, and the length in the longitudinal direction and the lateral direction. The resin composition of [1], which has a phase-separated structure in which five or more phases are observed as a phase having a length ratio (transverse length/longitudinal length) of 0.5 or less;
[3] In the resin composition, the oxygen permeability (OTR) of the single-layer film in the case of producing the single-layer film is (-20Et+870)×e ^{(0.1531[Et])/} 1554.33<OTR<( A resin composition of [1] or [2], which satisfies −20 ^Et +1900)×e ^{(0.1531×[Et])/} 1554.33;
[4] Any one of [1] to [3], wherein the mass ratio (A)/(B) of the ethylene-vinyl alcohol copolymer (A) and the polyolefin (B) is 13/87 to 47/53. Resin composition;
[5] The resin composition of [4], wherein the mass ratio (A)/(C) of the ethylene-vinyl alcohol copolymer (A) and the modified polyolefin (C) is 1.7 to 100;
[6] The resin composition of [4] or [5], in which the MFR of the ethylene-vinyl alcohol copolymer (A) is larger than the MFR of the polyolefin (B);
[7] The resin composition according to any one of [4] to [6], wherein the MFR of the polyolefin (B) is 3.0 g/10 minutes or less;
[8] The ratio MFR(EVOH)/MFR(PO) of the MFR of the ethylene-vinyl alcohol copolymer (A) and the MFR of the polyolefin (B) is 6.0 to 100. Resin composition;
[9] Any one of [1] to [3], wherein the mass ratio (A)/(B) of the ethylene-vinyl alcohol copolymer (A) and the polyolefin (B) is 53/47 to 87/13. Resin composition;
[10] The resin composition according to [9], wherein the mass ratio (A)/(C) of the ethylene-vinyl alcohol copolymer (A) and the modified polyolefin (C) is 2.6 to 150;
[11] The resin composition of [9] or [10], wherein the ethylene-vinyl alcohol copolymer (A) has an MFR smaller than that of the polyolefin (B);
[12] The resin composition according to any one of [9] to [11], wherein the ethylene-vinyl alcohol copolymer (A) has an MFR of 3.0 g/10 minutes or less;
[13] The ratio MFR(EVOH)/MFR(PO) of the MFR of the ethylene-vinyl alcohol copolymer (A) and the MFR of the polyolefin (B) is 0.010 to 0.17, [11] or [12]. ] Resin composition;
[14] A molded article containing the resin composition according to any one of [1] to [13];
[15] A multilayer structure having a layer containing the resin composition according to any one of [1] to [13]. The MFR (melt flow rate) in the present invention means the outflow rate (g/10 minutes) of a sample under the conditions of a temperature of 190° C. and a load of 2,160 g in accordance with ASTM D1238 using a melt indexer. The value obtained by measurement is shown.

The resin composition of the present invention can give a molded product having an excellent balance between gas barrier properties and mechanical properties. The resin composition of the present invention is preferably used for molded products and multilayer structures. The molded product and the multilayer structure can be suitably used as a packaging material for food and drink, a packing material for containers, a medical infusion bag material, a tire tube material, a shoe cushion material, and the like.

5 is a scanning electron micrograph of the monolayer film obtained in Example 5. 5 is a scanning electron micrograph of the monolayer film obtained in Comparative Example 3. 3 is a three-dimensional X-ray micrograph of the monolayer film obtained in Example 5. 6 is a three-dimensional X-ray micrograph of the single-layer film obtained in Example 5, which is an observation image in a direction perpendicular to the observation surface of FIG. 3. It is the evaluation result of the rheological property in a molten state about the resin composition obtained in Example 5 and Comparative Example 5, and each raw material. It is an evaluation result of the rheological property in a molten state about the resin composition obtained by the comparative example 3 and the comparative example 4, and each raw material. It is the evaluation result of the rheological property in the solid state about the resin composition obtained in Example 5 and Comparative Example 5, and each raw material. It is the evaluation result of the rheological property in a solid state about the resin composition obtained by the comparative example 3 and the comparative example 4, and each raw material.

<Resin composition>
The resin composition of the present invention contains an ethylene-vinyl alcohol copolymer (A), a polyolefin (B) and a modified polyolefin (C), and the ethylene-vinyl alcohol copolymer (A), the polyolefin (B) and The modified polyolefin (C) forms a three-dimensional network structure. By forming a three-dimensional network structure in the resin composition of the present invention, a molded article and a multilayer structure containing the resin composition have excellent gas barrier properties and mechanical properties. In the present specification, the upper limit value and the lower limit value of the numerical range (content of each component, value calculated from each component, each physical property, etc.) can be appropriately combined, and “upper limit” and “lower limit” are designated. In that case, the boundary value shall be included.

[EVOH(A)]
EVOH (A) is a copolymer having ethylene units and vinyl alcohol units. EVOH (A) includes, for example, ethylene and vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate and vinyl versatate. It is obtained by saponifying a copolymer with vinyl ester using an alkali catalyst or the like. The EVOH (A) may have a structural unit derived from a monomer other than ethylene and vinyl ester as long as the object of the present invention is not impaired. The other monomer is, for example, unsaturated acid such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid or the anhydride, salt, or mono- or dialkyl ester thereof; nitrile such as acrylonitrile or methacrylonitrile; acrylamide. , Amides such as methacrylamide; olefin sulfonic acids such as vinyl sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid or salts thereof; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloyl Vinylsilane compounds such as oxypropyltrimethoxysilane; alkyl vinyl ethers, vinyl ketones, N-vinylpyrrolidone, vinyl chloride, vinylidene chloride and the like.

EVOH (A) may have a structural unit (I) represented by the following formula (I) or a structural unit (II) represented by the following formula (II) as long as the object of the present invention is not impaired. Good. When the EVOH (A) has such a structural unit, the bending resistance and the like of the obtained molded body and multilayer structure can be further improved.

In the formula (I), R ¹ , R ² and R ³ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group having 3 to 10 carbon atoms, It represents an aromatic hydrocarbon group or a hydroxyl group having 6 to 10 carbon atoms. Further, any ^{two of} R ¹ , R ² and R ³ may be bonded. Moreover, the hydrogen atom which the said C1-C10 aliphatic hydrocarbon group has, the hydrogen atom which a C3-C10 alicyclic hydrocarbon group has, and the hydrogen which a C6-C10 aromatic hydrocarbon group has. Part or all of the atoms may be substituted with a hydroxyl group, a carboxy group or a halogen atom.

In the formula (II), R ⁴ , R ⁵ , R ⁶ and R ⁷ are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, or an alicyclic carbon atom having 3 to 10 carbon atoms. It represents a hydrogen group, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a hydroxyl group. R ⁴ and R ⁵ , or R ⁶ and R ⁷ may be bonded. Moreover, the hydrogen atom which the said C1-C10 aliphatic hydrocarbon group has, the hydrogen atom which a C3-C10 alicyclic hydrocarbon group has, and the hydrogen which a C6-C10 aromatic hydrocarbon group has. Part or all of the atoms may be substituted with a hydroxyl group, an alkoxy group, a carboxy group or a halogen atom.

When EVOH (A) has the structural unit (I) or (II), the lower limit of the content of the structural unit (I) or (II) is 0.5 mol% based on all the structural units of EVOH (A). Preferably, 1.0 mol% is more preferable, and 1.5 mol% is further preferable. On the other hand, the upper limit of the content of the structural unit (I) or (II) is preferably 30 mol%, more preferably 15 mol%, further preferably 10 mol%. When the EVOH (A) has the structural unit represented by (I) or (II) in the ratio within the above range, the flexibility and processing characteristics of the resin composition are improved, and as a result, the obtained molded product and multilayer structure are Stretchability and thermoformability can be improved.

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

In the structural unit (I), R ¹ , R ² and R ³ are each independently a hydrogen atom or a methyl group from the viewpoint of further improving the stretchability and thermoformability of the obtained molded body and multilayer structure. , An ethyl group, a hydroxyl group, a hydroxymethyl group and a hydroxyethyl group are preferable, and among these, a hydrogen atom, a methyl group, a hydroxyl group and a hydroxymethyl group are more preferable.

Examples of the method of incorporating the structural unit (I) into EVOH (A) include a method of copolymerizing a monomer derived from the structural unit (I) in the polymerization of ethylene and a vinyl ester. .. Examples of the monomer derived from the structural unit (I) include alkenes such as propylene, butylene, pentene and hexene; 3-hydroxy-1-propene, 3-acyloxy-1-propene, 3-acyloxy-1-butene, 4 -Acyloxy-1-butene, 3,4-diacyloxy-1-butene, 3-acyloxy-4-hydroxy-1-butene, 4-acyloxy-3-hydroxy-1-butene, 3-acyloxy-4-methyl-1 -Butene, 4-acyloxy-2-methyl-1-butene, 4-acyloxy-3-methyl-1-butene, 3,4-diacyloxy-2-methyl-1-butene, 4-hydroxy-1-pentene, 5 -Hydroxy-1-pentene, 4,5-dihydroxy-1-pentene, 4-acyloxy-1-pentene, 5-acyloxy-1-pentene, 4,5-diacyloxy-1-pentene, 4-hydroxy-3-methyl -1-Pentene, 5-hydroxy-3-methyl-1-pentene, 4,5-dihydroxy-3-methyl-1-pentene, 5,6-dihydroxy-1-hexene, 4-hydroxy-1-hexene, 5 -Hydroxy-1-hexene, 6-hydroxy-1-hexene, 4-acyloxy-1-hexene, 5-acyloxy-1-hexene, 6-acyloxy-1-hexene, 5,6-diacyloxy-1-hexene, etc. Examples thereof include alkenes having a hydroxyl group or an ester group. Among them, propylene, 3-acetoxy-1-propene, 3-acetoxy-1-butene, 4-acetoxy-1-butene, and the like from the viewpoint of copolymerization reactivity and gas barrier properties of the obtained molded article and multilayer structure. 3,4-diacetoxy-1-butene is preferred. In the case of an alkene having an ester, it is derived into the structural unit (I) during the saponification reaction.

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

As a method of incorporating the structural unit (II) into EVOH (A), a method of incorporating it by reacting EVOH (A) with a monovalent epoxy compound is used. As the monovalent epoxy compound, compounds represented by the following formulas (III) to (IX) are preferably used.

In the formulas (III) to (IX), R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are each independently a hydrogen atom, an aliphatic hydrocarbon group having 1 to 10 carbon atoms (alkyl group, An alkenyl group), an alicyclic hydrocarbon group having 3 to 10 carbon atoms (cycloalkyl group, cycloalkenyl group, etc.) or an aliphatic hydrocarbon group having 6 to 10 carbon atoms (phenyl group, etc.). Further, i, j, k, p and q each independently represent an integer of 1 to 8.

Examples of the monovalent epoxy compound represented by the formula (III) include epoxyethane (ethylene oxide), epoxypropane, 1,2-epoxybutane, 2,3-epoxybutane, and 3-methyl-1,2-epoxy. Butane, 1,2-epoxypentane, 3-methyl-1,2-epoxypentane, 1,2-epoxyhexane, 2,3-epoxyhexane, 3,4-epoxyhexane, 3-methyl-1,2-epoxy Hexane, 3-methyl-1,2-epoxyheptane, 4-methyl-1,2-epoxyheptane, 1,2-epoxyoctane, 2,3-epoxyoctane, 1,2-epoxynonane, 2,3-epoxy Nonane, 1,2-epoxydecane, 1,2-epoxydodecane, epoxyethylbenzene, 1-phenyl-1,2-propane, 3-phenyl-1,2-epoxypropane and the like can be mentioned.

Examples of the monovalent epoxy compound represented by the formula (IV) include various alkyl glycidyl ethers. Examples of the monovalent epoxy compound represented by the formula (V) include various alkylene glycol monoglycidyl ethers. Examples of the monovalent epoxy compound represented by the formula (VI) include various alkenyl glycidyl ethers. Examples of the monovalent epoxy compound represented by the formula (VII) include various epoxy alkanols such as glycidol. Examples of the monovalent epoxy compound represented by the formula (VIII) include various epoxy cycloalkanes. Examples of the monovalent epoxy compound represented by the formula (IX) include various epoxy cycloalkenes.

Among the above monovalent epoxy compounds, epoxy compounds having 2 to 8 carbon atoms are preferable. In particular, from the viewpoint of easy handling of the compound and reactivity, the number of carbon atoms of the monovalent epoxy compound is more preferably 2 to 6, and further preferably 2 to 4. Further, the monovalent epoxy compound is particularly preferably the compound represented by the formula (III) and the compound represented by the formula (IV) in the above formula. Specifically, 1,2-epoxybutane, 2,3-epoxybutane, epoxypropane, and epoxyethane from the viewpoints of reactivity with EVOH (A) and gas barrier properties of the obtained molded product and multilayer structure. And glycidol are preferable, and among them, epoxypropane and glycidol are particularly preferable.

The lower limit of the ethylene content of EVOH (A) is preferably 20 mol%, more preferably 25 mol%, even more preferably 27 mol%. The upper limit of the ethylene content of EVOH (A) is preferably 60 mol%, more preferably 55 mol%, and even more preferably 50 mol%. When the ethylene content is less than the above lower limit, the melt moldability of the resin composition tends to decrease. On the other hand, when the ethylene content exceeds the upper limit, the gas barrier property of the resin composition tends to deteriorate. The method for measuring the ethylene content and the measuring conditions are as described in Examples below.

From the viewpoint of maintaining the gas barrier property of the resin composition, the lower limit of the saponification degree of EVOH (A) is preferably 90 mol%, more preferably 95 mol%, and even more preferably 99 mol%. The method for measuring the degree of saponification and the measuring conditions are as described in Examples below. In addition, EVOH (A) may be used individually by 1 type, or may use 2 or more types together.

In the resin composition of the present invention, when the mass ratio (A)/(B) of EVOH (A) and PO (B) is less than 1, MFR of EVOH (A) (hereinafter, also referred to as “MFR (EVOH)”) 1.0 g/10 minutes is preferable, 1.5 g/10 minutes is more preferable, 2.5 g/10 minutes is still more preferable, and 5.0 g/10 minutes is particularly preferable. On the other hand, the upper limit of MFR (EVOH) is preferably 100 g/10 minutes, more preferably 50 g/10 minutes, even more preferably 30 g/10 minutes. By using such an MFR EVOH (A), the moldability and processability of the resin composition are improved, and EVOH (A), PO (B) and modified polyolefin (C) are easily formed into a three-dimensional network structure. Are preferable because they can be formed.

In the resin composition of the present invention, when the mass ratio (A)/(B) of EVOH (A) and PO (B) is 1 or more, the lower limit of MFR (EVOH) is preferably 0.05 g/10 minutes, 0.07 g/10 minutes is more preferable, and 0.1 g/10 minutes is even more preferable. On the other hand, the upper limit of MFR (EVOH) is preferably 5.0 g/10 minutes, more preferably 3.0 g/10 minutes, further preferably 2.0 g/10 minutes, and particularly preferably 1.0 g/10 minutes. By using such an MFR EVOH (A), the moldability and processability of the resin composition are improved, and EVOH (A), PO (B) and modified polyolefin (C) are easily formed into a three-dimensional network structure. Are preferable because they can be formed.

The lower limit of the content of EVOH (A) in the resin composition of the present invention is preferably 10% by mass, more preferably 15% by mass, and further preferably 20% by mass. The upper limit of the content of EVOH (A) in the resin composition is preferably 90% by mass, more preferably 85% by mass, and even more preferably 80% by mass. When the content of EVOH (A) in the resin composition is within the above range, EVOH (A), PO (B) and modified polyolefin (C) can easily form a three-dimensional network structure, gas barrier properties and mechanical properties. It is preferable because both of the above can be achieved.

In one embodiment, it is preferable that the resin composition of the present invention has a mass ratio (A)/(B) of EVOH (A) and PO (B) of less than 1 from the viewpoint of better mechanical properties. In that case, the lower limit of the content of EVOH (A) in the resin composition of the present invention is preferably 10% by mass, more preferably 15% by mass, and further preferably 20% by mass. Further, the upper limit of the content of EVOH (A) is preferably 47% by mass, more preferably 45% by mass, and even more preferably 41% by mass from the viewpoint of improving mechanical properties.

In another embodiment, it is preferable that the mass ratio (A)/(B) of EVOH (A) and PO (B) in the resin composition of the present invention is 1 or more from the viewpoint of better gas barrier properties. In that case, the lower limit of the content of EVOH (A) in the resin composition of the present invention is preferably 40% by mass, more preferably 45% by mass, and further preferably 50% by mass. In addition, the upper limit of the content of EVOH (A) is preferably 90% by mass, more preferably 85% by mass, and even more preferably 80% by mass from the viewpoint of improving the gas barrier property.

[PO(B)]
PO(B) means a polyolefin having no site capable of reacting with EVOH(A), and is preferably an unmodified polyolefin. Examples of PO(B) include homopolymers or copolymers of ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and the like. Among them, ethylene-based copolymers or ethylene homopolymers are preferable, and ethylene homopolymers, that is, polyethylene are more preferable. Examples of polyethylene include ultra low density polyethylene, (linear) low density polyethylene, high density polyethylene, polypropylene and the like.

In the resin composition of the present invention, when the mass ratio (A)/(B) of EVOH (A) and PO (B) is less than 1, MFR of PO (B) (hereinafter also referred to as “MFR (PO)”) The lower limit of () is preferably 0.05 g/10 minutes, more preferably 0.07 g/10 minutes, still more preferably 0.1 g/10 minutes. The upper limit of MFR(PO) is preferably 3.0 g/10 minutes, more preferably 2.0 g/10 minutes, still more preferably 1.0 g/10 minutes. When the MFR (PO) is within the above range, EVOH (A), PO (B) and modified polyolefin (C) can easily form a three-dimensional network structure while maintaining good melt moldability, which is preferable.

In the resin composition of the present invention, when the mass ratio (A)/(B) of EVOH (A) and PO (B) is 1 or more, the lower limit of MFR (PO) is preferably 1.0 g/10 minutes, 2.5 g/10 minutes is more preferable, and 5.0 g/10 minutes is even more preferable. On the other hand, the upper limit of MFR (PO) is preferably 100 g/10 minutes, more preferably 50 g/10 minutes, even more preferably 30 g/10 minutes. When the MFR (PO) is within the above range, the resin composition has good moldability and processability, and EVOH (A), PO (B) and modified polyolefin (C) easily form a three-dimensional network structure. It is preferable because it is possible.

The lower limit of the content of PO(B) in the resin composition of the present invention is preferably 10% by mass, more preferably 15% by mass, and further preferably 20% by mass. The upper limit of the content of PO(B) in the resin composition is preferably 90% by mass, more preferably 85% by mass, and even more preferably 80% by mass. When the content of PO(B) in the resin composition is within the above range, EVOH(A), PO(B) and modified polyolefin (C) can easily form a three-dimensional network structure, gas barrier properties and mechanical properties. It is preferable because both of the above can be achieved.

In one embodiment, it is preferable that the resin composition of the present invention has a mass ratio (A)/(B) of EVOH (A) and PO (B) of less than 1 from the viewpoint of better mechanical properties. In that case, the lower limit of the content of PO(B) in the resin composition of the present invention is preferably 40% by mass, more preferably 45% by mass, and further preferably 50% by mass. The upper limit of the content of PO(B) is preferably 90% by mass, more preferably 85% by mass, and even more preferably 80% by mass.

In another embodiment, it is preferable that the mass ratio (A)/(B) of EVOH (A) and PO (B) in the resin composition of the present invention is 1 or more from the viewpoint of better gas barrier properties. In that case, the lower limit of the content of PO(B) in the resin composition of the present invention is preferably 10% by mass, more preferably 15% by mass, and further preferably 20% by mass. The upper limit of the PO(B) content is preferably 47% by mass, more preferably 45% by mass, and even more preferably 41% by mass.

In the resin composition of the present invention, when the mass ratio (A)/(B) of EVOH(A) and PO(B) is less than 1, MFR(EVOH) is excellent in balance between gas barrier properties and mechanical properties. ) Is preferably larger than MFR(PO). For example, the lower limit of the ratio MFR(EVOH)/MFR(PO) of MFR(EVOH) to MFR(PO) is preferably 6.0, more preferably 8.0, further preferably 11 and particularly preferably 15. The upper limit of MFR(EVOH)/MFR(PO) is preferably 100, more preferably 70, further preferably 60, particularly preferably 50, and most preferably 40. When MFR(EVOH)/MFR(PO) is within the above numerical range, EVOH(A), PO(B) and modified polyolefin (C) can easily form a three-dimensional network structure, which is preferable.

In the resin composition of the present invention, when the mass ratio (A)/(B) of EVOH (A) and PO (B) is 1 or more, MFR (EVOH ) Is preferably smaller than MFR(PO). The lower limit of MFR(EVOH)/MFR(PO) is preferably 0.010, more preferably 0.014, further preferably 0.017, particularly preferably 0.020, and most preferably 0.025. The upper limit of MFR(PO)/MFR(EVOH) is preferably 0.17, more preferably 0.13, further preferably 0.09, particularly preferably 0.06. When MFR(PO)/MFR(EVOH) is within the above numerical range, EVOH(A), PO(B) and modified polyolefin (C) can easily form a three-dimensional network structure, which is preferable.

In the resin composition of the present invention, when the mass ratio (A)/(B) of EVOH (A) and PO (B) is less than 1, the lower limit of the mass ratio (A)/(B) is 13/87. 15/85 is more preferable, 18/82 is further preferable, 20/80 is particularly preferable, and 25/75 is the most preferable. When the mass ratio (A)/(B) is less than 1, the upper limit of the mass ratio (A)/(B) is preferably 47/53, more preferably 45/55. When the mass ratio (A)/(B) is within the above numerical range, EVOH (A), PO (B) and modified polyolefin (C) can easily form a three-dimensional network structure, which is preferable.

In the resin composition of the present invention, when the mass ratio (A)/(B) of EVOH (A) and PO (B) is 1 or more, the lower limit of the mass ratio (A)/(B) is 53/47. 55/45 is more preferable. When the mass ratio (A)/(B) is 1 or more, the upper limit of the mass ratio (A)/(B) is preferably 87/13, more preferably 85/15, and even more preferably 82/18. 80/20 is particularly preferred and 75/25 is most preferred. When the mass ratio (A)/(B) is within the above numerical range, EVOH (A), PO (B) and modified polyolefin (C) can easily form a three-dimensional network structure, which is preferable.

[Modified polyolefin (C)]
The modified polyolefin (C) contained in the resin composition of the present invention is a polyolefin having a modifying group capable of reacting with EVOH (A), and the modifying group is preferably a polar group. As the polar group, a sulfur-containing group such as a sulfonic acid group, a sulfenic acid group, and a sulfinic acid group; a hydroxyl group; a carbonyl group such as an epoxy group, a glycidyl group, a ketone group, an ester group, an aldehyde group, a carboxy group, and an acid anhydride group. Containing group; Nitrogen-containing group such as nitro group, amide group, urea group, isocyanate group; Phosphoric acid group, phosphonate ester group, phosphinic acid group, phosphinic acid ester group, and other phosphorus-containing group; Boronic acid group, boronic acid Examples thereof include boron-containing groups such as ester groups and boronic acid anhydride groups. Further, as the carboxy group-containing polyolefin, for example, carboxylic acid modified polyolefin and the like can be mentioned. As the monomer unit constituting the modified polyolefin (C), those exemplified for the PO (B) can be used. Examples of the carboxylic acid used in the carboxylic acid-modified polyolefin (C) include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride. Among them, maleic anhydride is preferably used.

The content of the modified polyolefin (C) is, for example, preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, based on 100 parts by mass of the total of EVOH (A) and PO (B). 5 parts by mass or more is more preferable, and 3.0 parts by mass or more is particularly preferable. Further, the content of the modified polyolefin (C) is preferably 22 parts by mass or less, more preferably 20 parts by mass or less, further preferably 17 parts by mass or less, particularly preferably 12 parts by mass or less, based on 100 parts by mass in total, and 8 It is most preferably not more than 10 parts by mass. When the content of the modified polyolefin (C) is 0.3 parts by mass or more based on 100 parts by mass in total, the resin composition of the present invention can easily form a three-dimensional network structure, which is preferable. Further, if the content of the modified polyolefin (C) is more than 22 parts by mass based on 100 parts by mass in total, the morphology of the resin composition of the present invention is in a finely dispersed state, which is not preferable.

In the resin composition of the present invention, when the mass ratio (A)/(B) of EVOH (A) and PO (B) is less than 1, the mass ratio (A) of EVOH (A) and modified polyolefin (C) is /(C) is preferably 1.7 or more, more preferably 2.5 or more, and further preferably 3.5 or more. When the mass ratio (A)/(B) is less than 1, the mass ratio (A)/(C) is preferably 100 or less, more preferably 50 or less, further preferably 20 or less, particularly preferably 15 or less. Most preferably, it is 10 or less. When the mass ratio (A)/(C) is within the above range, EVOH (A) and PO (B) exhibit appropriate compatibility, and EVOH (A), PO (B) and modified polyolefin (C) Is preferable because a three-dimensional network structure can be easily formed.

In the resin composition of the present invention, when the mass ratio (A)/(B) of EVOH (A) and PO (B) is 1 or more, the mass ratio (A) of EVOH (A) and modified polyolefin (C). /(C) is preferably 2.6 or more, more preferably 3.8 or more, still more preferably 5.3 or more. When the mass ratio (A)/(B) is 1 or more, the mass ratio (A)/(C) is preferably 150 or less, more preferably 75 or less, further preferably 30 or less, particularly preferably 23 or less. , 15 or less are most preferable. When the mass ratio (A)/(C) is within the above range, EVOH (A) and PO (B) exhibit appropriate compatibility, and EVOH (A), PO (B) and modified polyolefin (C) Is preferable because a three-dimensional network structure can be easily formed.

The lower limit of the total content of EVOH (A), PO (B) and modified polyolefin (C) in the resin composition of the present invention is preferably 80% by mass, more preferably 85% by mass, and even more preferably 90% by mass. The upper limit of the total content of EVOH (A), PO (B) and modified polyolefin (C) in the resin composition of the present invention is 100% by mass, 95% by mass or 90% by mass. May be.

[Other ingredients]
In addition to the above compounds (EVOH (A), PO (B), modified polyolefin (C)), the resin composition of the present invention contains various acids or metal salts or other compounds from the viewpoint of thermal stability or viscosity adjustment. It may be contained. Examples of this compound include a carboxylic acid, a phosphoric acid compound, and a boron compound, and specific examples will be described later. In addition, these compounds may be used by mixing with EVOH (A) in advance.

(Carboxylic acid and/or carboxylate ion)
By being contained in the resin composition of the present invention, the carboxylic acid and/or the carboxylate ion improves the coloring resistance of the resin composition during melt molding. Carboxylic acid is a compound having one or more carboxy groups in the molecule. The carboxylate ion is a hydrogen ion of the carboxy group of carboxylic acid desorbed. The carboxylic acid contained in the resin composition of the present invention may be a monocarboxylic acid, a polyvalent carboxylic acid compound having two or more carboxy groups in the molecule, or a combination thereof. The polyvalent carboxylic acid does not contain a polymer. Further, the polyvalent carboxylate ion is one in which at least one hydrogen ion of the carboxy group of the polyvalent carboxylic acid is eliminated. The carboxy group of the carboxylic acid may have an ester structure, and the carboxylic acid ion may form a salt with a metal.

The monocarboxylic acid is not particularly limited, and examples thereof include formic acid, acetic acid, propionic acid, butyric acid, caproic acid, capric acid, acrylic acid, methacrylic acid, benzoic acid and 2-naphthoic acid. These carboxylic acids may have a hydroxyl group or a halogen atom. In addition, examples of the carboxylate ion include those in which the hydrogen ion of the carboxy group of each of the above-mentioned carboxylic acids is eliminated. The pKa of the monocarboxylic acid (including the monocarboxylic acid that gives a monocarboxylic acid ion) is preferably 3.5 or more, more preferably 4 or more from the viewpoint of the pH adjusting ability and melt moldability of the composition. Examples of such monocarboxylic acids include formic acid (pKa=3.68), acetic acid (pKa=4.74), propionic acid (pKa=4.85), butyric acid (pKa=4.80), and the like. Acetic acid is preferred from the standpoint of easiness and the like.

The polycarboxylic acid is not particularly limited as long as it has two or more carboxy groups in the molecule, and examples thereof include oxalic acid, malonic acid, succinic acid, maleic acid, fumaric acid, glutaric acid, and adipine. Acids, aliphatic dicarboxylic acids such as pimelic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid; tricarboxylic acids such as aconitic acid; 1,2,3,4-butanetetracarboxylic acid, ethylenediaminetetraacetic acid, etc. A carboxylic acid having 4 or more carboxy groups; a hydroxycarboxylic acid such as tartaric acid, citric acid, isocitric acid, malic acid, mutic acid, tartronic acid, citramalic acid; oxaloacetic acid, mesooxalic acid, 2-ketoglutaric acid, 3-ketoglutar Examples thereof include ketocarboxylic acids such as acids; amino acids such as glutamic acid, aspartic acid, and 2-aminoadipic acid. Incidentally, examples of the polyvalent carboxylate ion include these anions. Among these, succinic acid, malic acid, tartaric acid, and citric acid are particularly preferable because they are easily available.

From the viewpoint of coloring resistance during melt molding, the content of carboxylic acid and carboxylate ion is preferably 20 μmol/g, more preferably 15 μmol/g, further preferably 10 μmol/g in terms of carboxylic acid radicals as the upper limit for the resin composition. preferable. The lower limit of the content is preferably 0.01 μmol/g, more preferably 0.05 μmol/g, even more preferably 0.5 μmol/g in terms of carboxylic acid radical.

(Phosphate compound)
The resin composition of the present invention may further contain a phosphoric acid compound. When the phosphoric acid compound is contained in the resin composition of the present invention, the long-run property at the time of melt molding of the resin composition can be improved. The phosphoric acid compound is not particularly limited, and examples thereof include various phosphorus oxygen acids such as phosphoric acid and phosphorous acid, and salts thereof. The phosphate may be contained in any form of, for example, a first phosphate, a second phosphate and a third phosphate, and its counter cation species may be, for example, an alkali metal salt or an alkali salt. Earth metal salts are preferred, and alkali metal salts are more preferred. Specifically, sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate or dipotassium hydrogen phosphate is preferable from the viewpoint of improving long-run property during melt molding.

The lower limit of the content of the phosphoric acid compound (phosphoric acid group equivalent content in the dry resin composition) is preferably 1 ppm, more preferably 5 ppm, and further preferably 8 ppm. On the other hand, the upper limit of the content of the phosphoric acid compound is preferably 500 ppm, more preferably 200 ppm, further preferably 50 ppm. If the content of the phosphoric acid compound is less than the lower limit, the long-run property improving effect during melt molding may not be sufficiently exhibited. On the other hand, when the content of the phosphoric acid compound exceeds the upper limit, gels or lumps of the molded product (defects in the appearance of the molded product obtained through melt extrusion or the like) are likely to occur. In the present specification, ppm represents mass ppm.

(Boron compound)
When the boron compound is contained in the resin composition of the present invention, the long-run property at the time of melt molding of the resin composition can be improved, and as a result, the occurrence of gel or lumps can be suppressed and the appearance characteristics can be improved. Specifically, when a boron compound is added to the resin composition, it is considered that a borate ester is generated between EVOH (A) and the boron compound, and such a resin composition can improve long-run property.

The boron compound is not particularly limited, and examples thereof include boric acids such as orthoboric acid (H ₃ BO ₃ ), metaboric acid and tetraboric acid; boric acid esters such as triethyl borate and trimethyl borate; alkalis of the various boric acids. Examples thereof include metal salts, alkaline earth metal salts, borates such as borax; and borohydrides. Of these, orthoboric acid is preferable.

The lower limit of the content of the boron compound (the content of the boron compound in the dry resin composition in terms of boron element) is preferably 5 ppm, more preferably 10 ppm, and further preferably 50 ppm. On the other hand, the upper limit of the content of the boron compound is preferably 2,000 ppm, more preferably 1,000 ppm, further preferably 500 ppm, particularly preferably 300 ppm. When the content of the boron compound is less than the lower limit, it is difficult to obtain the effect of improving the long-run property at the time of melt molding by adding the boron compound. On the contrary, when the content of the boron compound exceeds the above upper limit, the effect of improving the long-run property during melt molding tends to decrease.

The metal ion preferably contains an alkali metal ion. Examples of the alkali metal ion include ions of lithium, sodium, potassium, rubidium, cesium and the like, and sodium or potassium ion is preferable from the viewpoint of industrial availability. When the resin composition of the present invention contains an alkali metal ion, the long-run property and the interlayer adhesive force when forming a multilayer structure are improved.

Examples of the alkali metal salt that gives an alkali metal ion include aliphatic carboxylates such as lithium, sodium, and potassium, aromatic carboxylates, phosphates, metal complexes, and the like. Specifically, sodium acetate, Potassium acetate, sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, tripotassium phosphate, lithium dihydrogen phosphate, trilithium phosphate, stearic acid Examples thereof include sodium, potassium stearate, and a sodium salt of ethylenediaminetetraacetic acid. Of these, sodium acetate, potassium acetate, and sodium dihydrogen phosphate are particularly preferable because they are easily available.

The lower limit of the content of the alkali metal ion (content in the dry resin composition) is preferably 2.5 μmol/g, more preferably 3.5 μmol/g, further preferably 4.5 μmol/g. On the other hand, the upper limit of the content of alkali metal ions is preferably 22 μmol/g, more preferably 16 μmol/g, even more preferably 10 μmol/g. When the content of the alkali metal ion is smaller than the lower limit, the interlayer adhesion tends to decrease when the multilayer structure is molded. On the contrary, when the content of the alkali metal ions exceeds the upper limit, the appearance characteristics of the resin composition tend to deteriorate.

It is also preferred that the metal ions include alkaline earth metal ions. Examples of the alkaline earth metal ion include ions of beryllium, magnesium, calcium, strontium, barium, etc., and from the viewpoint of industrial availability, magnesium or calcium ion is more preferable. When the metal ion contains an alkaline earth metal ion, deterioration of the resin composition when the multilayer structure is repeatedly reused is suppressed, and defects such as gel or lumps are reduced, so that the appearance of the molded product is improved.

Further, to the resin composition of the present invention, various additives such as antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, etc. other than those described above are added to the extent that the effects of the present invention are not impaired. You may mix an agent. Examples of the antioxidant include 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 4,4′-thiobis-(6-t-butylphenol, 2,2′methylene. -Bis(4-methyl-6-t-butylphenol, tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, octadecyl-3-(3' 5,5-di-t-butyl-4'-hydroxyphenyl)propionate, 4,4'-thiobis-(6-t-butylphenol), etc. Examples of the ultraviolet absorber include ethyl-2-cyano-3, 3-diphenyl acrylate, 2-(2'-hydroxy-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'hydroxy-3'-t-butyl-5'-methylphenyl)-5-chloro Examples thereof include benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, etc. Examples of the plasticizer include dimethyl phthalate and diethyl phthalate. , Dioctyl phthalate, wax, liquid paraffin, phosphoric acid ester, etc. Antistatic agents include pentaerythritol monostearate, sorbitan monopalmitate, sulfated oleic acid, polyethylene oxide, carbowax, etc. Examples of the lubricant include ethylene bis-stearyl amide, butyl stearate, calcium stearate, zinc stearate, etc. Examples of the colorant include carbon black, phthalocyanine, quinacridone, indoline, azo pigment, titanium oxide, red iron oxide and the like. Examples of the filler include glass fiber, mica, ballastonite and the like.

In addition, a thermoplastic resin or a thermosetting resin other than EVOH (A), PO (B) and modified polyolefin (C) may be added to the resin composition as long as the object of the present invention is not impaired. Good. Examples of the thermoplastic resin include rubbers such as EPR (ethylene-propylene rubber), EPDM (ethylene-propylene-diene rubber), NR (natural rubber), isoprene rubber, butadiene rubber, IIR (butyl rubber); polyethylene. Resins such as polypropylene, polybutene, polyisobutylene, polyamide, and thermoplastic polyester. Examples of the thermosetting resin include epoxy resin, acrylic resin, urethane resin, thermosetting polyester, and modified products of these resins, either individually or as a mixture.

The content of the other components in the resin composition of the present invention is preferably 10 parts by mass or less, and 5 parts by mass or less based on 100 parts by mass of EVOH (A), PO (B) and modified polyolefin (C) in total. Is more preferable, and 1 part by mass or less is further preferable. The resin composition may contain substantially only EVOH (A), PO (B) and modified polyolefin (C) as a resin. In the present invention, containing substantially only one component means that the content of the other components is less than 5.0% by mass, preferably less than 1.0% by mass, and 0.5% by mass. Less than is more preferable.

In the resin composition of the present invention, EVOH (A), PO (B) and modified polyolefin (C) form a three-dimensional network structure. Here, “forming a three-dimensional network structure” means that the phase-separated EVOH (A) phase and PO (B) phase each form a three-dimensional network continuous phase. Further, not only when EVOH (A) and PO (B) form a continuous phase with each other, but EVOH (A) and PO (B) form a continuous phase with each other, and EVOH (A The case where there is a region having an island phase of PO(B) in the continuous phase of) and the region having an island phase of EVOH(A) in the continuous phase of PO(B) is also included. In any case, it is presumed that the modified polyolefin (C) exists inside or at the interface of the EVOH (A) phase and the PO (B) phase. The three-dimensional network structure can be confirmed using a scanning electron microscope (SEM) or a three-dimensional X-ray microscope.

The three-dimensional network structure of the resin composition of the present invention preferably specifically has the following phase separation structure. That is, when an arbitrary cross section of the resin composition of the present invention is observed with a three-dimensional X-ray microscope, EVOH (A) and PO (in the resin composition) in a 200 μm×200 μm square arbitrarily selected in the cross section are contained. The phase composed of the resin having the smaller content in B) has a length in the longitudinal direction of 20 μm or more and the ratio of the length in the longitudinal direction to the length in the lateral direction (lateral length/longitudinal length) is 0. Five or more phases of 5 or less are observed, and when an arbitrary cross section in the vertical direction of the cross section is observed by a three-dimensional X-ray microscope, a square of 200 μm×200 μm arbitrarily selected in the vertical cross section. Among them, the phase composed of the resin phase having the smaller content of EVOH (A) and PO (B) in the resin composition has a length in the longitudinal direction of 20 μm or more and It is preferable to have a phase-separated structure in which five or more phases are observed as a phase having a directional length ratio (shorter length/longer length) of 0.5 or less. FIG. 3 is a three-dimensional X-ray micrograph of the monolayer film obtained in Example 5, showing the relationship between the longitudinal length and the lateral length of the EVOH (A) phase (white portion in FIG. 3) on the low content side. It has a phase-separated structure that satisfies the above condition regarding the property.

According to the resin composition of the present invention, a molded article and a multilayer structure having excellent mechanical properties can be obtained. The index of mechanical properties of the resin composition can be evaluated by forming a film from the resin composition and determining the tensile elongation at break. The method for measuring the tensile elongation at break is as described in Examples below. As the lower limit of the tensile elongation at break of the film formed from the resin composition of the present invention, 100% is preferable, 300% is more preferable, 400% is further preferable, and 420% is particularly preferable. On the other hand, the upper limit of the tensile elongation at break of the film may be 1,200%.

The oxygen permeability of the film using the resin composition of the present invention is preferably 800 ml·20 μm/(m ² ·day·atm) or less, more preferably 550 ml·20 μm/(m ² ·day·atm) or less, and 300 ml. -20 μm/(m ² ·day·atm) or less is more preferable. The method for measuring the oxygen permeability of the film of the present invention and the measurement conditions are as described in Examples below.

The oxygen permeability (OTR) of the film using the resin composition of the present invention preferably satisfies the following formula. In addition, Et in a formula means the numerical value of the mass part of EVOH(A) with respect to the total of 100 mass parts of the weight of EVOH(A) and PO(B) in a resin composition. [Et] in the formula means the numerical value of the ethylene unit content of EVOH (A), and when the resin composition of the present invention contains a plurality of EVOH (A), it is calculated from the mass ratio thereof. It means the average value of ethylene unit content.
(Equation 1)
(-20Et+870)*e ^{(0.1531[Et])/} 1554.33<OTR<(-20Et+1900)*e ^{(0.1531*[Et])/} 1554.33
When the oxygen permeability satisfies the above formula, the oxygen permeability of the film using the resin composition of the present invention is preferably larger than (-20Et+870)×e ^{(0.1531[Et])/} 1554.33, and (-20Et+880). )×e ^{(0.1531[Et])/} 1554.33 is more preferable. Further, the oxygen permeability of the film using the resin composition of the present invention is preferably (-20Et+1900)×e ^{(0.1531×[Et])/} 1554.33, and (−20Et+1700)×e ^{(0.1531×[Et]). )} /1554.33 is more preferable, (-20Et+1500)×e ^{(0.1531×[Et])/} 1554.33 is further preferable, (-20Et+1300)×e ^{(0.1531×[Et])/} 1554.33 is less than Is particularly preferable. When the oxygen permeability is larger than (-20Et+870)*e ^{(0.1531[Et])/} 1554.33, a film having more excellent mechanical properties can be obtained. When the oxygen permeability is less than (-20Et+1900)xe ^{(0.1531x[Et])/} 1554.33, a film having a better gas barrier property can be obtained.

[Method for producing resin composition]
The method for producing the resin composition of the present invention comprises, for example, thoroughly mixing or kneading EVOH (A), PO (B), modified polyolefin (C), and optionally other additives under melting conditions. Manufactured. Mixing or kneading under melting conditions can be performed using a known mixing device or kneading device such as a kneader ruder, an extruder, a mixing roll, or a Banbury mixer. The temperature of mixing or kneading may be appropriately adjusted depending on the melting point of the EVOH (A) used, etc., but usually a temperature within a temperature range of 160° C. or higher and 300° C. or lower may be adopted, and 180° C. or higher and 290° C. It may be the following or 200° C. or more and 280° C. or less.

The resin composition of the present invention can be processed into an arbitrary form such as pellets and powders and used as a molding material, and a molded article having an excellent balance between gas barrier properties and mechanical properties can be obtained.

<Molded body>
The molded product of the present invention contains the resin composition. Since the resin composition of the present invention has thermoplasticity, it can be molded by using a usual molding method and molding apparatus used for general thermoplastic polymers. As the molding method, for example, any method such as injection molding, extrusion molding, press molding, blow molding, calender molding, vacuum molding, compression molding, etc. can be adopted. The shape of the molded product containing the resin composition produced by such a method includes a mold, a pipe, a sheet, a film, a disc, a ring, a bag, a bottle, a string, and a fibrous material. A wide variety of shapes are included, and a film shape is preferable. The molded body may substantially contain only the resin composition.

The molded product of the present invention can be used, for example, as a single-layer film-shaped structure. Suitable uses of the molded body are packaging materials for food and drink, packaging materials for containers, medical infusion bag materials, gasoline tank materials, tire tube materials, cosmetic packaging materials, pharmaceutical packaging materials, toothpaste packaging materials, And a cushion material for shoes.

<Multilayer structure>
The multilayer structure of the present invention has a layer containing the resin composition. The layer containing the resin composition may be a layer containing substantially only the resin composition. Since the multilayer structure of the present invention has the layer containing the resin composition, it is possible to improve moisture resistance, mechanical properties and the like. The number of layers constituting the multilayer structure is not particularly limited as long as it is 2 or more, but, for example, 2 or more and 10 or less is preferable, and 3 or more and 5 or less is more preferable.

The multilayer structure of the present invention has, for example, at least one layer containing the resin composition (the resin composition layer) and at least one layer made of another material. Other materials can be appropriately selected according to required characteristics, intended use, etc., and examples thereof include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and ethylene-propylene. Copolymers, polyolefins such as polypropylene; thermoplastic polymers such as ethylene-vinyl acetate copolymers, ethylene-acrylic ester copolymers, polystyrene, vinyl chloride resins, vinylidene chloride resins; and ionomers.

In the multilayer structure of the present invention, an adhesive layer or an adhesive may be interposed between the resin composition layer and a layer composed of another material. By interposing the adhesive layer or the adhesive, the two layers on both sides thereof can be firmly joined and integrated. Examples of the adhesive layer and the adhesive include an acid anhydride modified product of a diene polymer, an acid anhydride modified product of a polyolefin, and a mixture of a polymer polyol and a polyisocyanate compound. However, when the layer composed of other material is a polyolefin layer, the adhesive layer or the adhesive may not be interposed because the interlayer adhesion is excellent without the adhesive layer or the adhesive interposed. In addition, known methods such as coextrusion, coinjection, and extrusion coating can be used for forming the multilayer structure of the multilayer structure.

The multi-layer structure of the present invention has excellent balance between gas barrier properties and mechanical properties, and therefore can be used as daily necessities, packaging materials, machine parts and the like that require these properties. Examples of applications in which the features of the multilayer structure are particularly effectively exhibited are food and drink packaging materials, container packing materials, medical infusion bag materials, gasoline tank materials, tire tube materials, cosmetic packaging materials. , Packaging material for medicine, packaging material for toothpaste, cushion material for shoes, container, inner bag material for bag-in-box, tank material for storing organic liquid, pipe material for transporting organic liquid, hot water pipe material for heating (hot water for floor heating) Pipe material, etc.), resin wallpaper, etc. Of these, particularly preferable uses include packaging materials for food and drink, packaging materials for containers, medical infusion bag materials, gasoline tank materials, tire tube materials, cosmetic packaging materials, pharmaceutical packaging materials, toothpaste packaging materials, And a cushion material for shoes.

The present invention includes various combinations of the above configurations within the technical scope of the present invention as long as the effects of the present invention are exhibited.

Next, the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples, and many modifications can be made in the art within the technical idea of the present invention. This can be done by a person with ordinary knowledge. The analysis and evaluation in the following examples and comparative examples were performed as follows.

[Ethylene content and saponification degree of EVOH (A)]
The dry EVOH pellets were ground by freeze grinding. The obtained pulverized EVOH was sieved with a sieve having a nominal opening of 1.00 mm (standard sieving standard JIS-Z8801-1-2006). 5 g of the EVOH powder that passed through the sieve was immersed in 100 g of ion-exchanged water, stirred at 85° C. for 4 hours, drained and dried. Using the obtained washed powder EVOH, ¹ H-NMR measurement was performed under the following measurement conditions, and the ethylene content and the saponification degree were determined by the following analysis method.

Measurement conditions Device name: Superconducting nuclear magnetic resonance device "Lambda500" manufactured by JEOL Ltd.
Observation frequency: 500 MHz
Solvent: DMSO-d ₆
Polymer concentration: 4% by mass
Measurement temperature: 40℃ and 95℃
Number of integrations: 600 times Pulse delay time: 3.836 seconds Sample rotation speed: 10-12 Hz
Pulse width (90° pulse): 6.75 μsec

Analytical method In the measurement at 40° C., a hydrogen peak in the water molecule was observed around 3.3 ppm, and overlapped with the 3.1 to 3.7 ppm portion of the methine hydrogen peak of the vinyl alcohol unit of EVOH. It was On the other hand, in the measurement at 95° C., although the overlap generated at 40° C. is eliminated, the hydrogen peak of the hydroxyl group of the vinyl alcohol unit of EVOH present near 4 to 4.5 ppm is the methine of the vinyl alcohol unit of EVOH. It overlapped with the portion of 3.7 to 4.0 ppm in the hydrogen peak. That is, regarding the quantification of methine hydrogen (3.1 to 4.0 ppm) of the vinyl alcohol unit of EVOH, in order to avoid overlapping with the hydrogen peak of water or a hydroxyl group, the portion of 3.1 to 3.7 ppm is , The measurement data of 95° C. was adopted, and the measurement data of 40° C. was adopted for the portion of 3.7 to 4.0 ppm, and the total amount of the methine hydrogen was quantified as the total value thereof. It is known that the hydrogen peak of water or a hydroxyl group shifts to the high magnetic field side by increasing the measurement temperature. Therefore, analysis was performed using the measurement results at both 40° C. and 95° C. as follows. From the spectrum measured at 40° C., the integrated value (I ₁ ) of the peak of chemical shift of 3.7 to 4.0 ppm and the integrated value (I ₂ ) of the peak of chemical shift of 0.6 to 1.8 ppm were obtained. Ask. On the other hand, from the spectrum measured at 95° C., the integral value (I ₃ ) of the peak of chemical shift of 3.1 to 3.7 ppm, the integral value (I ₄ ) of the peak of chemical shift of 0.6 to 1.8 ppm, and The integrated value (I ₅ ) of the peak of the chemical shift of 1.9 to 2.1 ppm is obtained. Here, the peak of the chemical shift of 0.6 to 1.8 ppm is mainly derived from methylene hydrogen, and the peak of the chemical shift of 1.9 to 2.1 ppm is in the unsaponified vinyl acetate unit. It is derived from methyl hydrogen. The ethylene content and the degree of saponification were calculated from the integrated values by the following formulas.

[Melt flow rate (MFR)]
Using a melt indexer (trade name: “TECHNO SEVEN”, L244-2531, manufactured by Techno Seven Co., Ltd.), according to ASTM D1238, the sample outflow rate under the conditions of a temperature of 190° C. and a load of 2,160 g ( g/10 minutes) was measured and determined.

[Example 1]
40 parts of EVOH "EVAL (registered trademark) E105B (product name)" manufactured by Kuraray Co., Ltd. as an ethylene-vinyl alcohol copolymer (A), and high density polyethylene (HDPE) made by Prime Polymer Co., Ltd. as a polyolefin (B) " HY430 (product name)" and 60 parts of modified polyolefin (C) and maleic anhydride modified polyethylene "LOTADER (registered trademark) 3210 (product name)" manufactured by Arkema Co., Ltd. (Toyo Seiki Seisakusho Co., Ltd., "50M" biaxially different direction) at 240°C for 3 minutes at 20 rpm, then at 50 rpm for 7 minutes, and cut with scissors to obtain a 5 mm square melt blended product. ..

[Film production]
3 g of the melt-blended product obtained above was put in an aluminum frame of 10 cm×10 cm, and a hot press (manufactured by Imoto Seisakusho Co., Ltd.) “MH-10” was used to press at a pressure of 10 MPa at 200° C. to obtain a thickness. A 300 μm thick film (hereinafter referred to as a sample film) was obtained.

[Oxygen permeability (OTR)]
Using the sample film, the oxygen transmission rate (OTR) was evaluated. A part of the sample film is cut out, and MOCON INC. Oxygen transmission rate measuring device OX-TRAN 2/20 type (detection limit value 0.01 ml·20 μm/m ² ·day·atm) is used, 65% RH, temperature 20° C., oxygen pressure is 1 atm, carrier gas pressure Was measured under the condition of 1 atm according to the method described in JIS K 7126-2:2006 (isobaric method). Here, “0.01 ml·20 μm/m ² ·day·atm” means that when converted into a film thickness of 20 μm, the pressure difference between the film is 1 m ² and the oxygen gas is 1 atm. It means that 01 ml of oxygen permeates.

The oxygen permeability was evaluated according to the following evaluation criteria.
A: 300 ml·20 μm/m ² ·day·atm or less B: 300 ml·20 μm/m ² ·day·atm or larger,
550ml・20μm/m ²・day・atm or less C: 550ml・20μm/m ²・day・atm or more,
800 ml/20 μm/m ² ·day·atm or less D: Larger than 800 ml/20 μm/m ² ·day·atm

[Tensile breaking elongation]
The sample film was cut into a dumbbell shape to prepare a test piece. The size of the sample piece was 60 mm in total length, 10 mm in central length, 4 mm in central width, and 300 μm in thickness. Between chucks using a precision universal testing machine (trade name: Autograph EZ-Test, JIS B 7721:2009 class 0.5 and ISO 750-1 (2004) class 0.5, Shimadzu Corporation) A constant speed tensile test was performed on the test piece under conditions of a distance of 10 mm and a tensile speed of 20 mm/min to measure the tensile elongation at break.

The tensile elongation at break was evaluated according to the following evaluation criteria.
A: 400% or more B: 250% or more and less than 400% C: 100% or more and less than 250% D: Less than 100%

[Measurement of phase separation structure]
The cross section was observed using a scanning electron microscope S-3000N (manufactured by Hitachi, Ltd.). The sample was immersed in liquid nitrogen for 3 minutes to break at a cryogenic temperature, and the fracture surface of the sample was immersed in DMSO at 60° C. for 1 hour to dissolve only EVOH. Pt was vapor-deposited on the resin composition and the film to be measured, and the acceleration voltage was set to 15.0 kV. The measurement was performed in a high vacuum atmosphere. Further, the sample was observed from an arbitrary cross section and a direction perpendicular to the cross section using a three-dimensional X-ray microscope nano3DX (manufactured by Rigaku Corporation). Observation with a three-dimensional X-ray microscope was performed under the conditions of 500 images, a resolution of 0.54 μm/pixel, and an X-ray source of Cr. Those having a "three-dimensional network structure" were selected from the observation results of the three-dimensional X-ray microscope, and those not corresponding to the "three-dimensional network structure" were classified into "sea island structure" and "fine dispersion" from the SEM image.

[Example 2]
The same operation as in Example 1 except that the EVOH (A) used in Example 1 was changed to EVOH “Eval (registered trademark) G110B (product name)” manufactured by Kuraray Co., Ltd. having the characteristics described in Table 1. And evaluation was performed. The results are shown in Table 2.

[Example 3]
The EVOH (A) used in Example 1 was changed to EVOH "Eval (registered trademark) F101B (product name)" manufactured by Kuraray Co., Ltd. having the characteristics shown in Table 1, and PO (B) was changed to Prime Polymer Co., Ltd. The same operation and evaluation as in Example 1 were performed, except that the high density polyethylene (HDPE) “2110JH (product name)” manufactured was used and the composition ratio was changed as shown in Table 1. The results are shown in Table 2.

[Example 4]
Except that PO(B) used in Example 3 was changed to Mitsubishi Chemical Corporation's low density polyethylene (LLDPE) "Novatech (registered trademark) UJ790 (product name)" having the properties shown in Table 1. The same operation and evaluation as in Example 3 were performed. The results are shown in Table 2.

[Example 5]
The EVOH (A) used in Example 1 was changed to EVOH “Eval (registered trademark) G130B (product name)” manufactured by Kuraray Co., Ltd. having the characteristics shown in Table 1, and the same operation and evaluation as in Example 1 were performed. Was done. The results are shown in Table 2. The observation result of the scanning electron microscope is shown in FIG.

[Examples 6 to 13]
As shown in Table 1, the same operation and evaluation as in Example 5 were performed except that the blending ratio of EVOH (A), PO (B) and modified polyolefin (C) was changed. The results are shown in Table 2.

[Example 14]
The same operation and evaluation as in Example 5 were performed except that the modified polyolefin (C) used in Example 5 was changed to maleic anhydride modified polyethylene “LOTADER (registered trademark) 3410 (trade name)” manufactured by Arkema Ltd. I did. The results are shown in Table 2.

[Example 15]
The same operation and evaluation as in Example 5 were performed except that the modified polyolefin (C) used in Example 5 was changed to maleic anhydride-modified polyethylene "BONDINE (registered trademark) LX4110 (trade name)" manufactured by Arkema Ltd. I did. The results are shown in Table 2.

[Comparative Example 1]
The same operation as in Example 1 except that the EVOH (A) used in Example 1 was changed to EVOH “Eval (registered trademark) E171B (trade name)” manufactured by Kuraray Co., Ltd. having the characteristics shown in Table 1. And evaluation was performed. The results are shown in Table 2.

[Comparative example 2]
The same operation as in Example 1 except that the EVOH (A) used in Example 1 was changed to "Eval (registered trademark) E173B (trade name)" manufactured by Kuraray Co., Ltd. having the characteristics shown in Table 1. An evaluation was done. The results are shown in Table 2.

[Comparative Example 3]
The PO(B) used in Example 5 was changed to a high density polyethylene (HDPE) "HI-ZEX 2200J (trade name)" made by Prime Polymer Co., Ltd. having the properties shown in Table 1, and a modified polyolefin (C) was used. The same operations and evaluations as in Example 5 were carried out except that (1) was not used. The results are shown in Table 2. Moreover, the observation result of the scanning electron microscope is shown in FIG.

[Comparative Example 4]
The same operation and evaluation as in Comparative Example 3 were performed except that maleic anhydride-modified polyethylene "LOTADER (registered trademark) 3210 (trade name)" manufactured by Arkema Ltd. was used as the modified polyolefin (C). The results are shown in Table 2.

[Comparative Example 5]
The same operations and evaluations as in Example 5 were performed, except that the maleic anhydride-modified polyethylene "LOTADER (registered trademark) 3210 (trade name)" manufactured by Arkema Ltd. used in Example 5 was not used. The results are shown in Table 2.

[Comparative Example 6]
In Example 5, 40 parts of EVOH (A) "EVAL (registered trademark) G130B (product name)" and 60 parts of polyolefin (B) "HY430 (product name)" and modified polyolefin (C) "LOTADER (registered trademark)" ) 3210 (product name)” 5 parts by dry blending, and using a Labo Plastomill (“50M” biaxial different direction manufactured by Toyo Seiki Seisakusho Co., Ltd.) at 240° C. for 3 minutes at 20 rpm, and then at 150 rpm for 10 minutes. The same evaluation as in Example 5 was carried out except that a 5 mm square melt-blended product was obtained by kneading the mixture and cutting it with scissors. The results are shown in Table 2.

[Comparative Examples 7 to 10]
As shown in Table 1, the same operation and evaluation as in Example 5 were performed except that the blending ratio of EVOH (A), PO (B) and modified polyolefin (C) was changed. The results are shown in Table 2.

[Comparative Example 11]
The same as Example 5, except that the modified polyolefin (C) used in Example 5 was changed to Tosoh Corporation saponified ethylene vinyl acetate copolymer "Mersen (registered trademark) H-6051 (trade name)". The operation and evaluation were performed. The results are shown in Table 2.

[Comparative Example 12]
Same as Example 5, except that the modified polyolefin (C) used in Example 5 was changed to Tosoh Corporation saponified ethylene vinyl acetate copolymer "Mersen (registered trademark) H-6410M (trade name)". The operation and evaluation were performed. The results are shown in Table 2.

[Evaluation of rheological properties in molten state]
Bohlin Instruments Ltd. The rheological properties in the molten state were evaluated using "CVO-100" manufactured by the company. The resin compositions obtained in Example 5 and Comparative Example 5, EVOH “Eval (registered trademark) G130B (product name)” manufactured by Kuraray Co., Ltd., which was used as a raw material for each of them, and high-density polyethylene (prime polymer manufactured by HDPE) “HY430 (product name)” was used, and the measurement was performed under the conditions of 200° C., frequency range 0.1 to 20 Hz (18 points), gap 0.1 mm, and nitrogen atmosphere. The evaluation result is shown in FIG. In addition, the resin compositions obtained in Comparative Examples 3 and 4 and EVOH “EVAL (registered trademark) G130B (product name)” manufactured by Kuraray Co., Ltd. used as the respective raw materials and high density manufactured by Prime Polymer Co., Ltd. The same measurement as above was performed using polyethylene (HDPE) "HI-ZEX 2200J (trade name)". The evaluation result is shown in FIG. In the figure, G′ represents the storage elastic modulus, G″ represents the loss elastic modulus, η′ represents the dynamic viscosity, and ω represents the angular velocity. The resin composition obtained in Example 5 had a higher elastic modulus G″ at the lower frequency side than the resin composition obtained in Comparative Example 5. The resin compositions obtained in Comparative Examples 3 and 4 showed almost no difference. The resin composition obtained in Example 5 is presumed to have a reinforcing effect due to the three-dimensional network structure.

The rheological properties in the solid state were evaluated using "Rheogel-E4000" manufactured by UBM Co., Ltd. The resin compositions obtained in Example 5 and Comparative Example 5, EVOH “Eval (registered trademark) G130B (product name)” manufactured by Kuraray Co., Ltd., which was used as a raw material for each of them, and high-density polyethylene (prime polymer manufactured by HDPE) "HY430 (product name)" was used in the temperature range of -150 to 200[deg.] C. under the conditions of a temperature rising rate of 2[deg.] C./min, a frequency of 8 Hz, a tension mode, and a chuck distance of 20 mm. The evaluation result is shown in FIG. In addition, the resin compositions obtained in Comparative Examples 3 and 4 and EVOH “EVAL (registered trademark) G130B (product name)” manufactured by Kuraray Co., Ltd. used as the respective raw materials and high density manufactured by Prime Polymer Co., Ltd. The same measurement as above was performed using polyethylene (HDPE) "HI-ZEX 2200J (trade name)". The evaluation result is shown in FIG. In the figure, E'represents a storage elastic modulus, E'' represents a loss elastic modulus, and tan? represents a loss tangent. Regarding E′, E″, and tan δ, no significant difference was found between Example 5 and Comparative Example 5. Also, no significant difference was observed between Comparative Example 3 and Comparative Example 4.

INDUSTRIAL APPLICABILITY The resin composition of the present invention is useful for producing a molded product having an excellent balance between gas barrier properties and mechanical properties.

Claims (15)

Including ethylene-vinyl alcohol copolymer (A), polyolefin (B) and modified polyolefin (C),
The ethylene-vinyl alcohol copolymer (A), the polyolefin (B) and the modified polyolefin (C) form a three-dimensional network structure ,
A resin composition in which the modified polyolefin (C) is a carboxylic acid-modified polyolefin . When an arbitrary cross section of the resin composition is observed with a three-dimensional X-ray microscope, EVOH (A) and PO (B) of the resin composition in the arbitrarily selected 200 μm×200 μm square of the cross section are The phase composed of the resin with the smaller content has a length in the longitudinal direction of 20 μm or more and a ratio of the length in the longitudinal direction to the length in the lateral direction (lateral length/longitudinal length) of 0.5 or less. When five or more are observed as a certain phase and an arbitrary cross section in the vertical direction of such a cross section is observed by a three-dimensional X-ray microscope, the resin is placed in a 200 μm×200 μm square arbitrarily selected in the vertical cross section. The phase composed of the resin phase having the smaller content of EVOH (A) and PO (B) in the composition has a length of 20 μm or more in the longitudinal direction and has a length in the longitudinal direction and a length in the lateral direction. The resin composition according to claim 1, which has a phase-separated structure in which five or more are observed as a phase having a ratio (transverse length/longitudinal length) of 0.5 or less. In the resin composition, the oxygen permeability (OTR) of the single-layer film in the case of producing the single-layer film is (-20Et+870)×e ^{(0.1531[Et])/} 1554.33<OTR<(-20Et+1900) The resin composition according to claim 1 or 2, which satisfies xe ^(0.1531 x ^[Et]) /1554.33. The resin composition according to any one of claims 1 to 3, wherein the mass ratio (A)/(B) of the ethylene-vinyl alcohol copolymer (A) and the polyolefin (B) is 13/87 to 47/53. .. The resin composition according to claim 4, wherein the mass ratio (A)/(C) of the ethylene-vinyl alcohol copolymer (A) and the modified polyolefin (C) is 1.7 to 100. The resin composition according to claim 4 or 5, wherein the ethylene-vinyl alcohol copolymer (A) has a MFR larger than that of the polyolefin (B). The resin composition according to claim 4, wherein the polyolefin (B) has an MFR of 3.0 g/10 minutes or less. The resin composition according to claim 6 or 7, wherein a ratio MFR(EVOH)/MFR(PO) of the MFR of the ethylene-vinyl alcohol copolymer (A) and the MFR of the polyolefin (B) is 6.0 to 100. .. The resin composition according to any one of claims 1 to 3, wherein the mass ratio (A)/(B) of the ethylene-vinyl alcohol copolymer (A) and the polyolefin (B) is 53/47 to 87/13. .. The resin composition according to claim 9, wherein the mass ratio (A)/(C) of the ethylene-vinyl alcohol copolymer (A) and the modified polyolefin (C) is 2.6 to 150. The resin composition according to claim 9 or 10, wherein the ethylene-vinyl alcohol copolymer (A) has an MFR smaller than that of the polyolefin (B). The resin composition according to any one of claims 9 to 11, wherein the ethylene-vinyl alcohol copolymer (A) has an MFR of 3.0 g/10 minutes or less. The resin according to claim 11 or 12, wherein a ratio MFR(EVOH)/MFR(PO) of MFR of the ethylene-vinyl alcohol copolymer (A) and MFR of the polyolefin (B) is from 0.010 to 0.17. Composition. A molded product comprising the resin composition according to claim 1. A multi-layer structure having a layer containing the resin composition according to claim 1.

Images