Multilayer composite film and multilayer structure comprising the same

Abstract

A multilayer composite film comprises: a layer (X); a layer (Y); and a layer (Z) laminated adjacently in this order, wherein the layer (X) is an outermost layer and comprises an inorganic layer (I) and a protective layer (P) on an exposed surface side, wherein the layer (X) is made of a resin composition (A) containing an EVOH (a) having an ethylene unit content of 20 to 50 mol% and a saponification degree of 90 mol% or more as a main component, the layer (Y) contains an adhesive resin (B) having a melting point of less than 150°C as a main component, the layer (Z) contains a polyolefin resin (C) having a melting point of less than 150°C as a main component, the resin composition (A) contains from 40 to 500 ppm of alkali metal ion (b), and the multilayer composite film does not contain a layer containing a resin having a melting point of 200°C or more as a main component,and does not include a metal layer with an average thickness of 1 µm or more. While using a polyolefin with low heat resistance and a low melting point, such as polyethylene, such a multilayer composite film exhibits very good gas barrier properties and maintains stable gas barrier properties even after lamination.

Description

[0001] Title of the invention: Multilayer composite film and multilayer structure comprising the same. Technical area

[0002] The present invention relates to a multilayer composite film, a multilayer structure comprising the multilayer composite film, a packaging material containing the multilayer structure, a method for recycling the multilayer structure, and a recycled composition containing a recycled material from the multilayer structure. State of the art

[0003] Packaging materials for long-term food storage are often required to exhibit gas barrier properties, including oxygen barrier properties. The use of packaging materials with excellent gas barrier properties makes it possible to inhibit oxidative degradation of food and the proliferation of microorganisms due to oxygen permeation. As a layer to improve gas barrier properties, a film and vapor deposition of metals such as aluminum, and layers of deposited inorganic oxides, including silicon oxide and aluminum oxide, are widely used. Resin layers with gas barrier properties, such as vinyl alcohol-based polymers and polyvinylidene chloride, are also widely used.Such a vinyl alcohol-based polymer has the property that hydroxyl groups in the molecule bond together via hydrogen bonds, resulting in crystallization and an increase in density, thereby providing gas barrier properties. In particular, ethylene-vinyl alcohol copolymers (hereinafter referred to as "EVOHs") exhibit excellent heat stability and are therefore suitable for melt molding. With the development of coextrusion technology, multilayer films with an EVOH layer as an intermediate layer are widely used as packaging materials with gas barrier properties (Patent Document 1).

[0004] Additionally, in recent years, environmental and waste management concerns worldwide have triggered increased expectations for post-consumer recycling (hereinafter referred to simply as recycling), in which packaging materials consumed in the market are collected for resource recovery. The recycling process generally involves the steps of cutting collected packaging materials, separating and washing them if necessary, followed by melt mixing using an extruder. The resulting granules are used to manufacture various molded articles. In this regard, it is expected that packaging materials be composed of a single material (mono-material composition) whenever possible, thereby producing highly purified and high-quality recycled resins.For this purpose, there is an increased demand for barrier films containing polyethylene, which is widely used for packaging materials, as a main material, and consequently, a vapor-deposited multilayer film is also proposed in which a polyethylene-based multilayer film having an EVOH layer as an outermost layer has an inorganic deposited layer laminated on an EVOH layer surface so as to have both gas barrier properties and recyclability (Patent Document 2). Document listPatent documents Patent document 1: WO 2020 / 071513 A1 Patent document 2: WO 2021 / 261560 A1 Summary of the inventionTechnical problem

[0005] However, unlike the case where polyester or polypropylene with high heat resistance and a high melting point is used as a main material, the case of using a polyolefin with low heat resistance and a low melting point, such as polyethylene, as a main material is likely to cause dimensional changes in the film due to thermal hysteresis during conversion processes such as printing and lamination, and cracks in the inorganic deposited layer, leading to a problem of a tendency toward deterioration of barrier properties. Furthermore, the case of a decrease in the lamination temperature (drying temperature, roller temperature, aging temperature, etc.)) to prevent deterioration of barrier properties, there is a problem of a reduction in the production rate and a reduction in the initial adhesive strength, so that it is likely to cause a problem of delamination during aging.

[0006] In view of such circumstances, a first object of the present invention is to provide a multilayer laminated film that exhibits excellent gas barrier properties while using a polyolefin with low heat resistance and a low melting point, such as polyethylene, as a main material, and stably exhibits gas barrier properties even after lamination. A second object of the present invention is to provide a multilayer structure excellent in appearance, gas barrier properties, and recyclability using the multilayer laminated film, a packaging material comprising the multilayer structure, a recycled composition comprising a recycled material from the multilayer structure, and a method for recycling the multilayer structure. Solution to the problem

[0007] As a result of intensive investigation into various combinations of resin composition and lamination structure, the present inventors have found that, in a polyethylene-based multilayer film in which an EVOH layer is an outermost layer, an inorganic deposited layer is laminated on a surface of the EVOH layer, and a specific protective layer is further laminated, a multilayer composite film with excellent gas barrier properties is obtained, which stably provides the gas barrier properties even after lamination. Furthermore, they have found that materials and a laminate structure used for the multilayer composite film and other layers laminated thereon are determined to obtain a multilayer structure having each of an appearance, gas barrier properties, and recyclability, and thus completed the present invention., the above problems are solved by providing a:. [1] A multi-layer composite film comprising: a layer (X); a layer (Y); and a layer (Z) which are adjacently laminated in this order, wherein the layer (X) is an outermost layer and comprises an inorganic layer (I) and a protective layer (P) on an exposed surface side, wherein the layer (X) is made of a resin composition (A) containing an ethylene-vinyl alcohol copolymer (a) having an ethylene unit content of 20 to 50 mol% and a saponification degree of 90 mol% or more as a main component, the layer (Y) contains an adhesive resin (B) having a melting point of less than 150 °C as a main component, the layer (Z) contains a polyolefin resin (C) having a melting point of less than 150 °C as a main component, the resin composition (A) contains from 40 to 500 ppm of alkali metal ion (b), and the multi-layer composite film does not comprise a layer containing a resin having a melting point of 200 °C or more as a main component and does not comprise a metal layer having an average thickness of 1 µm or more; [2] Multi-layer composite film according to [1], wherein the protective layer (P), the inorganic layer (I) and the layer (X) are adjacently laminated in this order; [3] The multilayer composite film according to [1] or [2], wherein the adhesive resin (B) is acid-modified polyethylene; [4] The multilayer composite film according to any one of [1] to [3], wherein the polyolefin resin (C) is polyethylene; [5] The multilayer composite film according to any one of [1] to [4], wherein the inorganic layer (I) is a deposited metal layer containing aluminum as a main component or a deposited inorganic oxide layer containing aluminum oxide or silicon oxide as a main component; [6] The multilayer composite film according to any one of [1] to [5], wherein the protective layer (P) contains a water-soluble resin and at least one metal compound selected from the group consisting of metal alkoxides, metal alkoxide hydrolysates and metal alkoxide hydrolysis condensation products; [7] The multi-layer composite film according to any one of [1] to [5], wherein the protective layer (P) contains a polyurethane resin as a main component; [8] The multi-layer composite film according to any one of [1] to [7], wherein the resin composition (A) contains 10 ppm or more and 300 ppm or less of at least one polyvalent metal ion (c) selected from the group consisting of magnesium ions, calcium ions and zinc ions; [9] The multilayer composite film according to any one of [1] to [8], wherein the ethylene-vinyl alcohol copolymer (a) is an ethylene-vinyl alcohol copolymer (a') having a melting point of less than 150 °C;

[10] The multilayer composite film according to [9], wherein the ethylene-vinyl alcohol copolymer (a') has a modifying group containing a primary hydroxyl group represented by the following general formula (I): where X is a hydrogen atom, a methyl group or a group represented by R 2 -OH, R 1 and R 2each independently represents a single bond, an alkylene group having a carbon number of 1 to 9, or an alkyleneoxy group having a carbon number of 1 to 9, and the alkylene group and the alkyleneoxy group optionally contain a hydroxyl group, an alkoxy group, or a halogen atom;

[11] Multilayer composite film according to

[10] , wherein in the general formula (I) R 1 is a methylmethyleneoxy group and X is a hydrogen atom;

[12] The multilayer composite film according to

[10] or

[11] , wherein in the ethylene-vinyl alcohol copolymer (a'), a content of the modifying group containing a primary hydroxyl group is 2 mol% or more and less than 20 mol%;

[13] A multilayer composite film according to any one of [1] to

[12] , wherein the multilayer film is not substantially stretched;

[14] The multilayer composite film according to any one of [1] to

[12] , wherein the multilayer film is substantially only uniaxially stretched by 3 times or more and less than 12 times;

[15] The multilayer composite film according to any one of [1] to

[12] , wherein the multilayer film is biaxially stretched by 3 times or more and less than 12 times in each direction;

[16] The multi-layer composite film according to any one of [1] to

[15] , wherein a ratio of an average total thickness of a layer or layers containing a polyethylene-based resin as a main component is 0.75 or more;

[17] The multi-layer composite film according to any one of [1] to

[16] , wherein a ratio of an average total thickness of a layer or layers containing a resin having ethylene units as a main component is 0.95 or more;

[18] The multilayer composite film according to any one of [1] to

[17] , wherein the multilayer film has an oxygen transmission rate under conditions of 20 °C, 65% relative humidity (RH), of 0.5 cm 3 / (m 2 · day · atm) or less, measured according to a method described in JIS K 7126-2: 2006;

[19] A multilayer structure obtained by laminating the multilayer composite film according to any one of [1] to

[18] and at least one resin layer (R) containing a thermoplastic resin (D) as a main component;

[20] Multilayer structure according to

[19] , wherein the thermoplastic resin (D) is polyethylene;

[21] Packaging material comprising the multilayer structure according to

[19] or

[20] ;

[22] Recycled composition comprising a recycled material from the multilayer structure according to

[19] or

[20] ; and

[23] A method for recycling a multilayer structure, the method comprising crushing the multilayer structure according to

[19] or

[20] , followed by melt forming. Advantageous effects of the invention

[0008] The present invention makes it possible to provide the multilayer composite film which has excellent gas barrier properties while using polyolefin with low heat resistance and a low melting point, such as polyethylene, as a main material, and which stably exhibits gas barrier properties even after lamination. Furthermore, by including the multilayer composite film, the present invention makes it possible to provide the multilayer structure having excellent appearance and both gas barrier properties and recyclability, and a packaging material using the multilayer structure. Furthermore, since the multilayer structure has good recyclability, the present invention makes it possible to provide the recycled composition comprising a recycled material from the multilayer structure and the method for recycling the multilayer structure.In this context, the term "recyclability" means that when melt-kneading a recycled material from the multilayer structure or packaging material of the present invention to produce a recycled composition, resin gelation is inhibited, and thus it is possible to efficiently produce a recycled composition with excellent appearance. The recyclability can be evaluated by the recycling test described in Examples. Description of embodiments

[0009] Embodiments of the present invention are described below. It should be noted that in the following description, specific materials (compounds, etc.) sometimes exemplify a specific function, but the present invention is not limited to the modes in which such a material is used. Furthermore, any of the exemplary materials may be used individually or in combination, unless otherwise specified.

[0010] The multilayer composite film of the present invention comprises: a layer (X); a layer (Y); and a layer (Z) which are adjacently laminated in this order, wherein the layer (X) is an outermost layer and comprises an inorganic layer (I) and a protective layer (P) on an exposed surface side, wherein the layer (X) is made of a resin composition (A) (hereinafter referred to as “resin composition (A)”) containing an ethylene-vinyl alcohol copolymer (a) (hereinafter referred to as “EVOH (a)”) having an ethylene unit content of 20 to 50 mol% and a saponification degree of 90 mol% or more as a main component, the layer (Y) contains an adhesive resin (B) (hereinafter referred to as “adhesive resin (B)”) having a melting point of less than 150 °C as a main component, the layer (Z) contains a polyolefin resin (C) (hereinafter referred to as “polyolefin resin (C)”) having a melting point of less than 150 °C as a main component, the resin composition (A) contains from 40 to 500 ppm of alkali metal ion (b), and the multi-layer composite film does not comprise a layer containing a resin having a melting point of 200 °C or more as a main component and does not comprise a metal layer having an average thickness of 1 µm or more.

[0011] The EVOH (a) has good affinity for the inorganic layer (I), and thus, the multilayer composite film of the present invention comprises layer (X), wherein layer (X) is an outermost layer and comprises an inorganic layer (I) on the exposed surface side, so that it has excellent gas barrier properties. Furthermore, the multilayer composite film comprises the protective layer (P) on the inorganic layer (I), and thus is composed to stably exhibit gas barrier properties even after lamination.In this regard, deterioration of gas barrier properties after lamination is a problem caused by the layer (Y) and the layer (Z) for providing good recyclability, since the layer (Y) and the layer (Z) are formed using materials having a small melting point and dimensional change due to thermal hysteresis during lamination, and as a result, the inorganic layer (I) cracks to deteriorate the gas barrier properties, and thus, this is a problem specific to the layer structure of the multi-layer composite film of the present invention.Furthermore, since both layer (Y) and layer (Z) contain resins having a melting point of less than 150°C as a main component, and the polyolefin resin (C) contained in layer (Z) and EVOH (a) can be easily melt-blended, the multilayer composite film of the present invention, which comprises layer (X), layer (Y), and layer (Z) laminated adjacently in this order, can be easily recycled. In this situation, the resin composition (A) contains from 40 to 500 ppm of alkali metal ion (b), so that the multilayer composite film can exhibit good recyclability.

[0012] It should be noted that the expression “a layer (X), a layer (Y) and a layer (Z) laminated adjacently in this order” here means that adjacent layers are directly layered, and specifically means that the layer (X), the layer (Y) and the layer (Z) are layered in this order, the layer (X) and the layer (Y) are directly layered, and the layer (Y) and the layer (Z) are directly layered.

[0013] The term “main component” refers to a component that accounts for more than 50% by mass.

[0014] The term “average thickness” of each layer other than the inorganic layer (I) and the like means an average value of thicknesses measured at any 5 points.

[0015] The term “ppm” stands for a content based on mass (mass ppm).

[0016] The term “polyethylene” means a homopolymer of ethylene, a copolymer of 80 mol% or more of ethylene and 20 mol% or less of an α-olefin monomer, and a copolymer of 90 mol% or more of ethylene and less than 10 mol% of a non-olefin monomer containing no atoms other than a carbon atom, an oxygen atom, and a hydrogen atom in a functional group.

[0017] The term "acid-modified polyethylene" refers to a polymer obtained by modifying polyethylene with acid. The acid-modified polyethylene may be a polymer obtained by introducing at least one of an acid group or an acid anhydride group into polyethylene.

[0018] The term "polyethylene-based resin" refers to polyethylene and modified polyethylene (acid-modified polyethylene, etc.). Modified polyethylene is a polymer obtained by modifying polyethylene.

[0019] Furthermore, the term "surface (or outer layer)" in the multilayer structure refers to an exposed surface, not to distinguish a front surface from a back surface. That is, the multilayer structure has two surfaces. Accordingly, the multilayer structure has two outermost layers. <Harzzusammensetzung (A) und Schicht (X)>

[0020] The multilayer composite film of the present invention is composed of a multilayer film comprising layer (X), layer (X) being an outermost layer, wherein layer (X) is made of a resin composition (A) containing an EVOH (a) having an ethylene unit content of 20 to 50 mol% and a saponification degree of 90 mol% or more as a main component, and the resin composition (A) contains 40 to 500 ppm of an alkali metal ion (b). The content of the EVOH (a) in the resin composition (A) is more than 50 mass%. The resin composition (A) may contain at least one polyvalent metal ion (c) selected from the group consisting of magnesium ions, calcium ions, and zinc ions, a higher aliphatic carboxylic acid (d) having a carbon number of 8 to 30, and other components described later, and the like. A detailed description is given below. <EVOH (a)>

[0021] The EVOH (a) is usually prepared by saponifying an ethylene-vinyl ester copolymer obtained by polymerizing ethylene and a vinyl ester. The EVOH (a) has an ethylene unit content of 20 to 50 mol%. An ethylene unit content of 20 mol% or more improves the melt-formability of the EVOH (a) and a crushed product of the multilayer composite film containing the EVOH (a). The ethylene unit content is preferably 23 mol% or more, more preferably 26 mol% or more, and may be 29 mol% or more. Furthermore, the ethylene unit content of 50 mol% or less improves the gas barrier properties of the multilayer composite film of the present invention. The ethylene unit content is preferably 46 mol% or less, more preferably 42 mol% or less, and may be 38 mol% or less. In addition, the EVOH (a) has a saponification degree of 90 mol% or more.The saponification degree represents the ratio of the number of vinyl alcohol units to the total number of vinyl alcohol units and vinyl ester units in the EVOH (a). A saponification degree of 90 mol% or more improves the gas barrier properties of the multilayer composite film of the present invention. The saponification degree is preferably 95 mol% or more, more preferably 99 mol% or more, and even more preferably 99.9 mol% or more. The ethylene unit content and the saponification degree of the EVOH (a) are determined by a . 1 H-NMR measurement obtained.

[0022] The EVOH (a) may be a mixture of two or more types of EVOH having different ethylene unit contents. In this case, the difference in ethylene unit content between EVOHs having the most different ethylene unit contents is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 15 mol% or less, and may be 3 mol% or more. Accordingly, the EVOH (a) may be a mixture of two or more types of EVOH having different saponification degrees. In this case, the difference in saponification degrees between EVOHs having the most different saponification degrees is preferably 7% or less, more preferably 5% or less, and may be 0.5% or more.In order to obtain both heat formability and gas barrier properties at a higher level, it is preferable to blend an EVOH (a-1) having an ethylene unit content of 24 mol% or more and less than 34 mol% and a saponification degree of 99 mol% or more and an EVOH (a-2) having an ethylene unit content of 34 mol% or more and less than 50 mol% and a saponification degree of 99 mol% or more at a blending mass ratio (a1 / a2) of 60 / 40 to 90 / 10 and use them as EVOH (a).

[0023] The EVOH (a) may be an EVOH (a') with a melting point of less than 150°C. The EVOH (a') with a melting point of less than 150°C enables the multilayer film comprising the layer (X) as an outermost layer containing the EVOH (a') as a main component to exhibit improved appearance and interlayer adhesion. This is possibly because the EVOH (a') with a melting point of less than 150°C causes an improvement in the fluidity of the polymer chain and consequently effective stress relaxation and effective maintenance of the adhesion reaction activity to an adjacent layer even at relatively low temperatures during melt molding and secondary processing such as stretching.In order to further improve the effects of the present invention, the EVOH (a') preferably has a melting point of less than 140°C, more preferably less than 130°C, and it may be less than 125°C or less than 120°C. Further, in view of the processing during melt molding and secondary processing such as stretching, and in view of heat resistance as a packaging material, the EVOH (a') preferably has a melting point of 80°C or more, more preferably 90°C or more, and even more preferably 100°C or more. The melting point of the EVOH (a') is adjusted by one of the following two or more of them in combination, while the following method (3) is a preferable example of the adjusting method in the present invention:. (1) Change in ethylene unit content (an increase in ethylene unit content causes a decrease in melting point) (2) Change in the degree of saponification (a decrease in the degree of saponification causes a decrease in the melting point) (3) Introduction of a modifying group containing a primary hydroxyl group (introduction of a modifying group containing a primary hydroxyl group causes a decrease in the melting point)

[0024] The modifying group containing a primary hydroxyl group used for the above (3) is preferably a modifying group containing a primary hydroxyl group represented by the following general formula (I). The degree of melting point reduction per rate of introduction of the modifying group depends on the structure of the modifying group containing a primary hydroxyl group to be introduced, and introducing 1 mol% of the modifying group containing a primary hydroxyl group represented by the following general formula (I) generally causes a decrease in the melting point by about 6°C to 9°C.Adjusting the melting point by this method allows a decrease in the melting point while relatively maintaining the gas barrier properties and heat stability, as well as inhibiting the decrease in interlayer adhesion to the layer (Y) and the inorganic layer (I) described later, and thus can provide a multilayer composite film particularly excellent in quality and performance. The reasons for this are considered to be that, for example, since the melting point can be lowered while maintaining the amount of hydroxy groups, the primary hydroxy group has a high adhesion reaction activity to the layer (Y) and the inorganic layer (I) described later, and the like.The content of the modifying group containing a primary hydroxyl group of the EVOH (a') can be appropriately adjusted in consideration of the balance between the melting point and various physical properties, and a content of 2 mol% or more and less than 20 mol% often results in well-balanced physical properties. The content of the modifying group containing a primary hydroxyl group of the EVOH (a') more preferably has a lower limit of 4 mol%, and even more preferably 6 mol%. Further, the content of the modifying group containing a primary hydroxyl group of the EVOH (a') more preferably has an upper limit of 15 mol%, and even more preferably 10 mol%. The modifying group containing a primary hydroxyl group can be introduced by means of copolymerization or a polymeric reaction. wherein X represents a hydrogen atom, a methyl group, or a group represented by R. 2-OH, R 1 and R 2 each independently represents a single bond, an alkylene group having a carbon number of 1 to 9 or an alkyleneoxy group having a carbon number of 1 to 9, and the alkylene group and the alkyleneoxy group optionally contain a hydroxyl group, an alkoxy group or a halogen atom.

[0025] In the general formula (I), X is preferably a hydrogen atom or a group represented by R 2 -OH, and more preferably a hydrogen atom. R 1 is preferably a single bond, an alkylene group having a carbon number of 1 to 5, or an alkyleneoxy group having a carbon number of 1 to 5, and more preferably a methylmethyleneoxy group. A unit in which X is a hydrogen atom and R 1a methylmethyleneoxy group, can be obtained, for example, by subsequent modification by reacting an EVOH with epoxypropane.

[0026] The EVOH (a) may contain additional monomer units other than ethylene units, vinyl ester units, vinyl alcohol units, and the modifying group containing a primary hydroxyl group, as long as the effects of the present invention are not impaired. The content of the additional monomer units is preferably 5 mol% or less, more preferably 3 mol% or less, even more preferably 1 mol% or less, and particularly preferably, they are substantially not contained. Examples of such an additional monomer include: α-olefins such asPropylene, n-butene, isobutylene and 1-hexene; acrylic acid and salts thereof; unsaturated monomers having an acrylic acid ester group; methacrylic acid and salts thereof; unsaturated monomers having a methacrylic acid ester group; acrylamide, N-methylacrylamide, N-ethylacrylamide, N,N-dimethylacrylamide, diacetoneacrylamide, acrylamidopropanesulfonic acid and salts thereof, and acrylamidopropyldimethylamine and salts thereof (e.g. quaternary salts); methacrylamide, N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidopropanesulfonic acid and salts thereof, methacrylamidopropyldimethylamine and salts thereof (e.g. quaternary salts); Vinyl ethers, such as methyl vinyl ester, ethyl vinyl ester, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether and 2,3-diacetoxy-1-vinyloxypropane; vinyl cyanides, such as acrylonitrile and methacrylonitrile; vinyl halides, such as vinyl chloride and vinyl fluoride; vinylidene halides, such asVinylidene chloride and vinylidene fluoride; allyl compounds such as allyl acetate, 2,3-diacetoxy-1-allyloxypropane and allyl chloride; unsaturated dicarboxylic acids such as maleic acid, itaconic acid and fumaric acid, and salts or esters thereof; vinylsilane compounds such as vinyltrimethoxysilane; isopropenyl acetate, 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane and 1,3-dibutyronyloxy-2-methylenepropane; and the like.

[0027] The EVOH (a) has an MFR, measured according to JIS K7210 (2014) (190°C, at a load of 2.16 kg), of preferably 0.2 to 20 g / 10 min. The MFR of the EVOH (a) is more preferably 0.5 g / 10 min or more, and even more preferably 0.8 g / 10 min or more. Further, the MFR of the EVOH (a) is more preferably 15 g / 10 min or less, even more preferably 10 g / 10 min or less, even more preferably 5 g / 10 min or less, and particularly preferably 3 g / 10 min or less. The EVOH (a) having an MFR within the above range causes an improvement in the melt-formability of the EVOH (a) and the crushed product of the multilayer composite film containing the EVOH (a). <Alkalimetallion (b)>

[0028] The resin composition (A) contains from 40 to 500 ppm of the alkali metal ion (b). The resin composition (A) containing the alkali metal ion (b) within the above range tends to significantly improve the interlayer adhesion to the layer (Y) described later. 40 ppm or less of the alkali metal ion (b) causes the resin composition (A) to be likely to thicken during melt molding, sometimes resulting in a defective appearance such as gel and hard spots, and a reduction in the interlayer adhesion to the layer (Y) described later. Furthermore, more than 500 ppm of the alkali metal ion (b) sometimes causes the resin composition (A) to be excessively decomposed during melt molding or to have a problem of coloring.In the multilayer structure of the present invention, a content of the alkali metal ion (b) of less than 40 ppm fails to inhibit resin gelation during melt-kneading of a recycled material from the multilayer structure and a packaging material thereof to produce a recycled composition, resulting in deterioration in recyclability. Furthermore, a content of the alkali metal ion (b) of more than 500 ppm causes excessive decomposition reaction of the resin during melt-kneading of a recycled material from the multilayer structure and a packaging material thereof to produce a recycled composition, resulting in deterioration in recyclability. In this regard, the lower limit of the content of the alkali metal ion (b) is preferably 80 ppm, and more preferably 120 ppm. The upper limit of the content of the alkali metal ion (b) is preferably 400 ppm, and more preferably 300 ppm.Furthermore, adjusting the content ratio of the alkali metal ion (b) and carboxylic acids described later enables even greater improvement of the melt formability and coloring resistance of the resin composition (A) to be obtained.

[0029] Examples of the alkali metal ion (b) include lithium, sodium, potassium, rubidium, and cesium ions, and sodium or potassium ions are preferred in view of commercial or industrial availability. In particular, the use of potassium ions sometimes enables the resin composition (A) to exhibit both high color tone and interlayer adhesion to the layer (Y) described later. Any one of these can be used singly, or two or more types can be used in combination.

[0030] Examples of an alkali metal compound for providing the alkali metal ion (b) include aliphatic carboxylates, aromatic carboxylates, carbonates, hydrochlorides, nitrates, sulfates, phosphates, hydroxides, and metal complexes of alkali metals such as lithium, sodium, and potassium. Of these, aliphatic carboxylates and phosphates are more preferred in terms of availability and handling. Preferred aliphatic carboxylates include acetates, caprylates, and stearates. <Mehrwertiges Metallion (c)>

[0031] The resin composition (A) preferably contains from 10 to 300 ppm of a polyvalent metal ion (c) which is at least one selected from the group consisting of magnesium ions, calcium ions, and zinc ions. A content of the polyvalent metal ion (c) of 10 ppm or more tends to inhibit thickening and appearance defects such as gel and hard spots during melt-molding of the resin composition (A). Furthermore, a content of the polyvalent metal ion (c) of 300 ppm or less tends to inhibit excessive decomposition and coloring of the resin composition (A) during melt-molding.In the multilayer structure of the present invention, a crosslinking reaction of the resin occurs during recycling, sometimes causing thickening and gelling, while a content of the multivalent metal ion (c) of 10 ppm or more inhibits thickening, gelling, and resin adhesion to the screw. Furthermore, a content of the multivalent metal ion (c) of 300 ppm or less enables inhibition of color tone deterioration during recycling while preventing defects during recycling. In this regard, the content of the multivalent metal ion (c) is preferably from 20 to 200 ppm, and more preferably from 30 to 150 ppm. The resin composition (A) preferably contains magnesium ions or calcium ions as the multivalent metal ion (c), and preferably contains magnesium ions.Furthermore, adjusting the content ratio of the polyvalent metal ion (c) and the carboxylic acid described later enables even greater improvement of the melt formability and coloring resistance of the resin composition (A) to be obtained.

[0032] Examples of a polyvalent metal compound for providing the polyvalent metal ion (c) include aliphatic carboxylates, aromatic carboxylates, carbonates, hydrochlorides, nitrates, sulfates, phosphates, hydroxides, and metal complexes of magnesium, calcium, and zinc. Of these, aliphatic carboxylates and hydroxides are more preferred in terms of availability and handling. Preferred aliphatic carboxylates include acetates, caprylates, and stearates. <Höhere aliphatische Carbonsäure (d)>

[0033] The resin composition (A) preferably contains from 100 to 4000 ppm of higher aliphatic carboxylic acid (d) having a carbon number of 8 to 30. Part or all of the higher aliphatic carboxylic acid (d) may be contained in the form of a salt, and may be contained as a salt of the alkali metal ion (b) and the polyvalent metal ion (c). The higher aliphatic carboxylic acid (d) is preferably caprylic acid or stearic acid. The multilayer film constituting the multilayer composite film of the present invention has the layer (X) made of the resin composition (A) as the outermost layer, and it is believed that the higher aliphatic carboxylic acid (d) acts as a lubricant on the die metal surface in a die and can thus prevent defective appearance due to uneven thickness of the multilayer film and gel and hard spots due to the residual resin.Therefore, the resin composition (A) preferably contains 100 ppm or more of the higher aliphatic carboxylic acid (d). Furthermore, a content of the higher aliphatic carboxylic acid (d) of 4000 ppm or less tends to inhibit thickening of the resin composition (A) during melt molding and maintain interlayer adhesion to the layer (Y) described later. In this regard, the content of the higher aliphatic carboxylic acid (d) is more preferably from 200 to 3000 ppm, and even more preferably from 300 to 2500 ppm.

[0034] The resin composition (A) may further contain components other than the EVOH (a), the alkali metal ion (b), the polyvalent metal ion (c), and the higher aliphatic carboxylic acid (d), as long as the effects of the present invention are not impaired. Examples of the additional components include an alkaline earth metal ion and a transition metal ion other than the polyvalent metal ion (c), carboxylic acids (monocarboxylic acids, polycarboxylic acids) other than the higher aliphatic carboxylic acid (d), thermoplastic resins other than the EVOH (a), phosphoric acid compounds, boron compounds, prooxidants, antioxidants (hindered phenolic compounds, etc.).), plasticizers, heat stabilizers (melt stabilizers), photoinitiators, deodorizers, ultraviolet absorbers, antistatic agents, lubricants, colorants, fillers, desiccants, fillers, pigments, dyes, processing aids, flame retardants, antifogging agents, and the like. From the viewpoint of enabling inhibition of coloring during melt-molding of a crushed product of the multilayer structure containing the resin composition (A), it is preferable to contain a carboxylic acid and / or a phosphoric acid compound. Furthermore, the content of a boron compound enables adjustment of the melt viscosity of the resin composition (A) and the crushed product of the multilayer structure containing the resin composition (A). <Carbonsäure>

[0035] The resin composition (A) preferably contains a carboxylic acid other than the higher aliphatic carboxylic acid (d). The lower limit of the carboxylic acid content is preferably 50 ppm, and more preferably 100 ppm. Further, the upper limit of the carboxylic acid content is preferably 400 ppm, and more preferably 350 ppm. A carboxylic acid content of 50 ppm or more tends to provide good coloring resistance. Furthermore, a carboxylic acid content of 400 ppm or less tends to enable maintenance of interlayer adhesion and inhibition of odor generation.

[0036] The carboxylic acid preferably has a pKa of 3.5 to 5.5. A carboxylic acid having a pKa within the above range increases the pH buffer capacity of the resin composition (A) to be obtained and further improves melt moldability, and also enables further improvement in coloration due to acidic substances and basic substances.

[0037] The carboxylic acid may be any of the monovalent carboxylic acids. Any one type may be used singly, or two or more types may be used in combination. Such a monovalent carboxylic acid refers to a compound having a carboxyl group in the molecule. Examples of the monovalent carboxylic acids having a pKa in the range of 3.5 to 5.5 include, but are not specifically limited to, formic acid (pKa = 3.77), acetic acid (pKa = 4.76), propionic acid (pKa = 4.85), acrylic acid (pKa = 4.25), and the like. These carboxylic acids may further have a substituent group such as a hydroxyl group, an amino group, and a halogen atom. Of these, acetic acid is preferred due to its high safety and easy availability and handling.

[0038] The carboxylic acid can be any of polycarboxylic acids. The carboxylic acid as a polycarboxylic acid sometimes enables even greater improvement in the high-temperature coloring resistance of the resin composition (A) and the coloring resistance of a melt-molded product or the crushed product of the multilayer structure to be obtained. Furthermore, it is also preferable that the polycarboxylic acid compound has three or more carboxyl groups. In this case, the coloring resistance can be more effectively improved. Such a polycarboxylic acid compound refers to a compound having two or more carboxyl groups in the molecule.In this case, the at least one carboxyl group preferably has a pKa in the range of 3.5 to 5.5, and examples include oxalic acid (pKa2 = 4.27), succinic acid (pKa1 = 4.20), fumaric acid (pKa2 = 4.44), malic acid (pKa2 = 5.13), glutaric acid (pKa1 = 4.30, pKa2 = 5.40), adipic acid (pKa1 = 4.43, pKa2 = 5.41), pimelic acid (pKa1 = 4.71), phthalic acid (pKa2 = 5.41), isophthalic acid (pKa2 = 4.46), terephthalic acid (pKa1 = 3.51, pKa2 = 4.82), citric acid (pKa2 = 4.75), tartaric acid (pKa2 = 4.40), glutamic acid (pKa2 = 4.07), Aspartic acid (pKa = 3.90) and the like. <Phosphorsäureverbindung>

[0039] The resin composition (A) may further contain a phosphoric acid compound. The lower limit of the content of the phosphoric acid compound is preferably 5 ppm based on phosphate residues. Furthermore, the upper limit of the content of the phosphoric acid compound is preferably 100 ppm based on phosphate residues. A content of the phosphoric acid compound within this range sometimes inhibits the coloration of the resin composition (A) to be obtained and the melt-molded product of the crushed product of the multilayer structure to be obtained, and improves heat stability.

[0040] Examples of the phosphoric acid compound to be used include various acids, such as phosphoric acid and phosphorous acid, salts thereof, and the like. The phosphate may be any of a monobasic phosphate, a dibasic phosphate, or a tribasic phosphate. The cationic species of the phosphate are preferably, but not specifically limited to, alkali metals or alkaline earth metals. Preferred phosphoric acid compounds include sodium dihydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, and dipotassium hydrogen phosphate. <borverbindung>

[0041] The resin composition (A) may further contain a boron compound. In the case where a boron compound is contained, the resin composition (A) preferably has a lower limit of 50 ppm, and more preferably 100 ppm, in terms of boron element. Further, the resin composition (A) preferably has an upper limit of 400 ppm, and more preferably 200 ppm, in terms of boron element. A boron compound content within this range is effective for improving the heat stability of the resin composition (A) and the crushed product of the resulting multilayer structure during melt molding, and sometimes for preventing gel and hard spots. In some cases, it is also effective for improving the stretch resistance and necking resistance during film formation and for improving the mechanical properties of the resulting molded articles.These effects are believed to result from the chelate interaction between the EVOH (a) and the boron compound.

[0042] Examples of the boron compound include boric acids, borate esters, borates, and borohydrides. Specific examples include: boric acids such as orthoboric acid (H3BO3), metaboric acid, and tetraboric acid; borate esters such as trimethyl borate and triethyl borate; borates such as alkali metal salts, alkaline earth metal salts, and borax of the aforementioned boric acids; and the like. Of these, orthoboric acid is preferred. <Gehinderte Phenolverbindung>

[0043] The resin composition (A) may further contain a hindered phenol compound as an antioxidant. When the hindered phenol compound is contained, the resin composition (A) preferably contains from 1,000 to 10,000 ppm of the hindered phenol compound. A content of 1,000 ppm or more enables inhibition of coloring, thickening, and gelation of the resin during melt-molding of the crushed product of the multilayer film. The content of the hindered phenol compound is more preferably 2,000 ppm or more. Furthermore, a content of the hindered phenol compound of 10,000 ppm or less enables inhibition of coloring and bleeding due to the hindered phenol compound. The content of the hindered phenol compound is more preferably 8,000 ppm or less.

[0044] The hindered phenol compound has at least one hindered phenol group. Such a hindered phenol group refers to a group in which a bulky substituent is bonded to at least one carbon atom adjacent to the carbon bonded to the hydroxyl group of phenol. As the bulky substituent, an alkyl group having 1 to 10 carbon atoms is preferred, and a t-butyl group is more preferred.

[0045] The hindered phenol compound is preferably in a solid state near room temperature. In view of inhibiting the bleeding of the compound, the hindered phenol compound preferably has a melting point or softening temperature of 50°C or more, more preferably 60°C or more, and even more preferably 70°C or more. In the same view, the hindered phenol compound preferably has a molecular weight of 200 or more, more preferably 400 or more, and even more preferably 600 or more. Further, the molecular weight is usually 2000 or less. Furthermore, in view of facilitating mixing with the EVOH (a), the hindered phenol compound preferably has a melting point or softening temperature of 200°C or less, more preferably 190°C or less, and even more preferably 180°C or less.

[0046] The hindered phenol compound preferably has an ester bond or an amide bond. Examples of the hindered phenol compound having an ester bond include esters of aliphatic carboxylic acids having a hindered phenol group and aliphatic alcohols, and examples of the hindered phenol compound having an amide bond include amides of aliphatic carboxylic acids having a hindered phenol group and aliphatic amines. Of these, the hindered phenol compound preferably has an amide bond.

[0047] Specific structural examples of the hindered phenol compound having an ester bond or an amide bond include pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], commercially available from BASF as Irganox 1010, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)stearylpropionate, commercially available as Irganox 1076, 2,2'-thiodiethylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], commercially available as Irganox 1035, 3-(3,5-di-tert-butyl-4-hydroxyphenyl)octadecylpropanoate, commercially available as Irganox 1135, bis(3-tert-butyl-4-hydroxy-5-methylbenzenepropanoic acid)ethylenebis(oxyethylene), commercially available as Irganox 245, 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], commercially available as Irganox 259, and N,N'-hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanamide], commercially available as Irganox 1098.Of these, N,N'-hexamethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanamide], commercially available as Irganox 1098, and pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], commercially available as Irganox 1010, are preferred, and Irganox 1098 is more preferred.

[0048] The resin composition (A) may further contain a thermoplastic resin other than the EVOH (a). Examples of the thermoplastic resin other than EVOH (a) include various polyolefins (polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene copolymers, copolymers of ethylene and α-olefins having a carbon number of 4 or more, copolymers of polyolefins with maleic anhydrides, ethylene-vinyl ester copolymers, ethylene-acrylic ester copolymers, or modified polyolefins obtained by graft-modification with an unsaturated carboxylic acid or a derivative thereof, etc.), various polyamides (nylon 6, nylon 6-6, nylon 6 / 66 copolymers, nylon 11, nylon 12, polymetaxylylene adipamide, etc.), various polyesters (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.).), polyvinyl chlorides, polyvinylidene chlorides, polystyrenes, polyacrylonitriles, polyurethanes, polycarbonates, polyacetals, polyacrylates, modified polyvinyl alcohol resins, and the like. The content of the above thermoplastic resin in the resin composition (A) is usually less than 40 mass%, preferably 30 mass% or less, more preferably less than 20 mass%, even more preferably less than 10 mass%, and may be less than 5 mass% or less than 1 mass%, and particularly preferably substantially not contained.

[0049] The proportion of the EVOH (a) in the resin constituting the resin composition (A) is preferably 60 mass% or more in view of better enhancing the effects of the present invention, more preferably 70 mass% or more, still more preferably 80 mass% or more, even more preferably 90 mass% or more, and particularly preferably 95 mass% or more, and the resin constituting the resin composition (A) may be composed substantially only of the EVOH (a).Moreover, the proportion of the EVOH (a) in the resin composition (A) is preferably 60 mass% or more in view of better enhancing the effects of the present invention, more preferably 70 mass% or more, still more preferably 80 mass% or more, even more preferably 90 mass% or more, and particularly preferably 95 mass% or more, and may be 98 mass% or more or 99 mass% or more, and the resin composition (A) may be composed substantially only of the EVOH (a) and the alkali metal ion (b).

[0050] The method for producing the resin composition (A) is not particularly limited, and the method enables production by melt-kneading the EVOH (a), the alkali metal ion (b), and optionally additional components including the polyvalent metal ion (c) and the higher aliphatic carboxylic acid (d). Each component can be directly mixed in a solid state such as a powder or a melt, or can be mixed as a dissolved component contained in a solution or as a dispersoid contained in a dispersion. As the solution and the dispersion, aqueous solutions and aqueous dispersions are preferred, respectively. For melt-kneading, for example, a known mixing device or kneading device such as a kneading extruder, an extruder, mixing rolls, and a Banbury mixer can be used.The temperature range during melt-kneading can be appropriately adjusted according to the melting points of the EVOH (a) and each component to be used, and the like, and usually, the range of 150°C to 250°C is employed. Moreover, the resin composition (A) can be prepared by adding some components to the EVOH (a) in advance and then adding the other required components as described above for melt-kneading. An example of the method of adding some components to the EVOH (a) in advance includes a method comprising immersing the EVOH (a) in the form of granules or powder in a solution in which components to be added are dissolved. As the solution, an aqueous solution is suitable. <Haftmittelharz (B) und Schicht (Y)>

[0051] The multilayer composite film of the present invention has the layer (Y) containing the adhesive resin (B) having a melting point of less than 150°C as a main component. The multilayer composite film of the present invention comprising the layer (Y) tends to result in a multilayer composite film having excellent appearance and interlayer adhesion. Furthermore, the inclusion of the layer (Y) is effective in improving the compatibility of the layer (X) with the layer (Z) during recycling and thus tends to improve recyclability. Examples of the adhesive resin (B) include carboxylic acid-modified polyolefin resins obtained by graft polymerizing a polyolefin resin with an unsaturated carboxylic acid such as maleic anhydride or a derivative thereof.The melting point of the adhesive resin (B) depends primarily on the polyolefin resin before the carboxylic acid modification of the polyolefin resin. The same applies to the polyolefin resin as described later for the polyolefin resin (C).

[0052] The proportion of the carboxylic acid-modified polyolefin resin in the adhesive resin (B) is preferably 70 mass% or more, more preferably 80 mass% or more, and even more preferably 95 mass% or more, and the adhesive resin (B) may be composed essentially only of the carboxylic acid-modified polyolefin resin. Furthermore, the proportion of the adhesive resin (B) in the layer (Y) is preferably 70 mass% or more, more preferably 80 mass% or more, and even more preferably 95 mass% or more, and the layer (Y) may be composed essentially only of the adhesive resin (B). <Polyolefinharz (C) und Schicht (Z)>

[0053] The multilayer composite film of the present invention has the layer (Z) containing the polyolefin resin (C) having a melting point of less than 150°C as a main component. The polyolefin resin (C) may be any polyethylene having a melting point of less than 150°C, but is not specifically limited thereto, and examples thereof include: polyethylene-based resins such as linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, and high-density polyethylene; vinyl ester resins; ethylene-propylene copolymers; propylene-α-olefin copolymers (α-olefins having a carbon number of 4 to 20); homo- or copolymers of olefins such as polybutene and polypentene; chlorinated polyethylene; and the like.In order to improve the recyclability of the multilayer structure containing the polyolefin resin (C), the polyolefin resin (C) preferably contains such a polyethylene-based resin as a main component, and more preferably is such a polyethylene-based resin. Polyethylene-based resins, regardless of whether they have gas barrier properties, are widely used for packaging materials, and consequently, infrastructures for their recycling are being extensively developed in many countries.When the polyolefin resin (C) contains the polyethylene-based resin as a main component, the polyethylene-based resin is preferably at least one selected from linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, or high-density polyethylene, and more preferably at least one selected from linear low-density polyethylene or low-density polyethylene, or a mixture of high-density polyethylene and at least one selected from linear low-density polyethylene or low-density polyethylene.

[0054] In order to further improve the effects of the present invention, the melting point of the polyolefin resin (C) is preferably less than 140°C, and more preferably less than 130°C. Furthermore, in view of the processability during melt molding and secondary processing such as stretching, and in view of heat resistance as a packaging material, the melting point of the polyolefin resin (C) is preferably 80°C or more, and more preferably 90°C or more. Moreover, in view of improving melt moldability, the polyolefin resin (C) preferably has a melt flow index (MFR) (190°C, at a load of 2160 g) measured according to the method prescribed in JIS K7210 (2014) of 0.1 to 30 g / 10 min, more preferably 0.3 to 25 g / 10 min, and even more preferably 0.5 to 20 g / 10 min.

[0055] The polyolefin resin (C) preferably contains the polyethylene-based resin as a main component, and the content of the polyethylene-based resin in the polyolefin resin (C) is more preferably 70 mass% or more, even more preferably 80 mass% or more, and particularly preferably 95 mass% or more, and the polyolefin resin (C) may be substantially composed of only the polyethylene-based resin. Moreover, the content of the polyolefin resin (C) in the layer (Z) is preferably 70 mass% or more, more preferably 80 mass% or more, and even more preferably 95 mass% or more, and the layer (Z) may be substantially composed of only the polyolefin resin (C).

[0056] Layer (Y) and layer (Z) each contain the adhesive resin (B) and the polyolefin resin (C) as a main component, and as long as the effects of the present invention are not impaired, these layers may contain other components such as antioxidants, plasticizers, heat stabilizers (melt stabilizers), photoinitiators, deodorizers, ultraviolet absorbers, antistatic agents, lubricants, colorants, fillers, desiccants, fillers, pigments, dyes, processing aids, flame retardants, and antifogging agents. It should be noted that the total amount of these components in each layer is less than 50 mass%, preferably less than 40 mass%, more preferably less than 30 mass%, even more preferably less than 20 mass%, and particularly preferably less than 10 mass%, and may be less than 5 mass%, less than 3 mass%, or less than 1 mass%. <mehrschichtfolie>

[0057] The multilayer film constituting the multilayer composite film of the present invention comprises: at least the layer (X); the layer (Y); and the layer (Z), which are adjacently laminated in this order, with the layer (X) being an outermost layer. The multilayer film may have a plurality of layers for each of the layer (X), the layer (Y), and the layer (Z). Examples of the layer constitution of the multilayer film of the present invention include X / Y / Z, X / Y / Z / Y / X, X / Y / Z / Y / X / Y / Z / Y / X, and the like, where X, Y, and Z denote the layer (X), the layer (Y), and the layer (Z), respectively, and " / " denotes directly laminated.

[0058] In view of gas barrier properties, recyclability, and economy, the layer (X) of the multilayer film preferably has an average thickness of 0.2 μm or more and less than 20 μm. It is also preferable that the proportion of the average thickness of the layer (X) to the total thickness of the average thickness of the multilayer film is less than 25%. The layer (X) more preferably has an average thickness of 0.4 μm or more and less than 16 μm, and even more preferably 0.6 μm or more and less than 12 μm. The proportion of the average thickness of the layer (X) to the total thickness of the average thickness of the multilayer film is more preferably less than 20%, and even more preferably less than 15%.

[0059] In view of interlayer adhesion, recyclability, and economy, the layer (Y) of the multilayer film preferably has an average thickness of 0.2 μm or more and less than 20 μm. It is also preferable that the proportion of the average thickness of the layer (Y) to the total thickness of the average thickness of the multilayer film is less than 25%. The layer (Y) more preferably has an average thickness of 0.4 μm or more and less than 16 μm, and even more preferably 0.6 μm or more and less than 12 μm. The proportion of the average thickness of the layer (Y) to the total thickness of the average thickness of the multilayer film is more preferably less than 20%, and even more preferably less than 15%.

[0060] In terms of recyclability, the layer (Z) of the multilayer film preferably has an average thickness of 1 μm or more and less than 200 μm. It is also preferable that the proportion of the average thickness of the layer (Z) to the total thickness of the average thickness of the multilayer film is more than 55%. The layer (Z) more preferably has an average thickness of 5 μm or more, even more preferably 10 μm or more, and this may be 20 μm or more. The layer (Z) also more preferably has an average thickness of 100 μm or less, and this may be 50 μm or less. The proportion of the average thickness of the layer (Z) to the total thickness of the average thickness of the multilayer film is more preferably more than 60%, and even more preferably more than 70%.The multilayer film typically has an average thickness of 10 µm or more and less than 200 µm, and preferably 10 µm or more and less than 150 µm. When the multilayer film is a stretched multilayer film described later, the stretched multilayer film preferably has an average thickness of 10 µm or more and less than 50 µm, and more preferably less than 40 µm.

[0061] The multilayer film may be an unstretched multilayer film or a stretched multilayer film that is uniaxially or biaxially (at least uniaxially) stretched. In the case of the unstretched multilayer film, the film has excellent impact resistance and can also be suitably used as a heat-sealable film. Furthermore, uniaxial or biaxial stretching enables improvement in the mechanical properties and gas barrier properties of the resulting multilayer film. The multilayer film is preferably a uniaxially stretched multilayer film in view of economy and ease of tearing the multilayer film (when used as a packaging material, ease of opening the packaging material), and the multilayer film is preferably a biaxially stretched multilayer film in view of less anisotropy of mechanical properties and the production of a tough film.In view of uniform thickness and mechanical strength of the multilayer film to be obtained, the film is preferably at least uniaxially stretched by 3 times or more and less than 12 times. In the case of such a uniaxially stretched multilayer film, the film is preferably uniaxially stretched by 3 times or more and less than 12 times, and more preferably uniaxially stretched by 4 times or more and less than 10 times. In the case of such a biaxially stretched multilayer film, the film is preferably biaxially stretched by 3 times or more and less than 12 times in each direction, and more preferably biaxially stretched by 4 times or more and less than 10 times in each direction.

[0062] The method for forming the multilayer film is not specifically limited, and it is generally possible to use coextrusion methods in which the respective resins are extruded and laminated from separate dies or a common die. As such a die, either a ring die or a T-die can be used. The method of uniaxial or biaxial stretching is also not specifically limited, and the multilayer film can be produced by stretching in the film traveling direction and / or in a direction orthogonal to the traveling direction, that is, in the width direction, using a conventionally known stretching method such as roll-type uniaxial stretching, tube-type simultaneous biaxial stretching, tenter-type sequential biaxial stretching, and tenter-type simultaneous biaxial stretching.Of these, the effects of the present invention are particularly pronounced for a multilayer film produced by sequential biaxial stretching of the tenter frame type. In view of processability, the temperature during stretching is usually from 40°C to 150°C, more preferably from 50°C to 140°C, and may be from 60°C to 130°C. The multilayer film constituting the multilayer composite film of the present invention has the advantage that problems, including defective appearance and reduction in interlayer adhesion, are less likely to occur after stretching even at a relatively low stretching temperature such as 120°C.After stretching, a so-called heat setting is preferably carried out, in which the product is heated at temperatures of the glass transition temperature or more or less than the melting point, so that the crystallinity is increased and, if necessary, the orientation of molecular chains is also fixed. <Anorganische Schicht (I)>

[0063] The multilayer composite film of the present invention comprises the inorganic layer (I) and the protective layer (P) on an exposed surface side of the layer (X) of the multilayer film. The inorganic layer (I) is preferably laminated directly to the exposed surface side of the layer (X) of the multilayer film or via another layer such as an adhesive layer, and more preferably directly laminated to the exposed surface side of the layer (X). The inorganic layer (I) is a layer made of an inorganic material such as metal and inorganic oxide, and has gas barrier properties with respect to oxygen and water vapor.Layer (X) has a higher affinity for metal and inorganic oxide compared with conventional thermoplastic resins, enabling the formation of the inorganic layer (I) having a high density and no defects, resulting in good interlayer adhesion between layer (X) and the inorganic layer (I) in the thus-obtained multilayer composite film. Furthermore, since layer (X) has gas barrier properties, deterioration of the gas barrier properties can be prevented even if defects are generated in the inorganic layer (I) due to bending or the like. The inorganic layer (I) generally has an average thickness of less than 500 nm.An average thickness of less than 500 nm results in excellent viscosity stability during melt-molding of the crushed product of the multilayer structure comprising the inorganic layer (I), and thus enables the prevention of gel and hard spots.

[0064] The inorganic layer (I) is preferably an inorganic deposited layer, and is preferably either a deposited metal layer containing aluminum as a main component or a deposited inorganic oxide layer containing aluminum oxide or silicon oxide as a main component. A deposited metal layer is preferable for imparting light-shielding properties, whereas an inorganic oxide deposited layer is preferable in view of the visibility of a content and microwaveability required for packaging materials, and in view of enabling the prevention of gel and hard spots during melt-molding of a crushed product. Furthermore, in view of inhibiting coloration during recycling of the multilayer structure of the present invention, an inorganic oxide deposited layer is preferable.Moreover, while a deposited inorganic oxide layer causes a more pronounced deterioration in gas barrier properties after lamination than a deposited metal layer when the protective layer (P) is not provided, the use of the protective layer (P) does not result in a large difference in gas barrier properties after lamination between the deposited metal layer and the deposited inorganic oxide layer, and thus, it is considered that the use of the deposited inorganic oxide layer better enhances the effects of applying the present invention.

[0065] The deposited metal layer is a layer containing aluminum as a main component. The aluminum atom content in the deposited metal layer is preferably 50 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more. The deposited metal layer preferably has an average thickness of 120 nm or less, more preferably 100 nm or less, and even more preferably 90 nm or less. Furthermore, the deposited metal layer preferably has an average thickness of 25 nm or more, more preferably 35 nm or more, and even more preferably 45 nm or more. It should be noted that the average thickness of the deposited metal layer refers to an average value of thicknesses at 10 points arbitrarily selected in a cross section of the deposited metal layer and measured with an electron microscope.The inclusion of the deposited metal layer enables the multilayer composite film of the present invention to have a light transmittance at a wavelength of 600 nm of 10% or less, thereby obtaining excellent light-shielding properties.

[0066] It should be noted that in the deposited metal layer containing aluminum as a main component, irreversible oxide sometimes occurs and may partially contain aluminum oxide. In the deposited metal layer containing aluminum as a main component (inorganic deposited layer (B)), the molar ratio (0 mol / Al mol) of the oxygen atom content to the aluminum atom content is preferably 0.5 or less, more preferably 0.3 or less, and even more preferably 0.1 or less.

[0067] Examples of the inorganic oxide deposited layer include vapor-deposited films of an inorganic oxide such as an oxide of silicon, aluminum, magnesium, calcium, potassium, tin, sodium, boron, titanium, lead, zirconium, yttrium, or the like, preferably vapor-deposited films of aluminum oxide or silicon oxide. The inorganic oxide deposited layer preferably has an average thickness of 150 nm or less, and more preferably 110 nm or less, and the thickness may preferably be 80 nm or less or 60 nm or less in view of recyclability. The inorganic oxide deposited layer also has an average thickness of preferably 10 nm or more, more preferably 20 nm or more, and even more preferably 30 nm or more.It should be noted that the average thickness of the deposited inorganic oxide layer refers to an average value of thicknesses at 10 points arbitrarily selected in a cross section of the deposited inorganic oxide layer, which are measured with an electron microscope. The inclusion of the deposited inorganic oxide layer enables the multilayer composite film of the present invention to have a light transmittance at a wavelength of 600 nm of 80% or more, resulting in excellent visibility of a content when used as a packaging material. In view of further improving visibility, the light transmittance at a wavelength of 600 nm is more preferably 90% or more.Light transmittance can be increased, for example, by preventing unevenness in the thickness of the multilayer film to be used to produce the multilayer composite film. An example of a method for further preventing unevenness in the thickness of the multilayer film includes a method that includes at least uniaxial stretching. The light transmittance of the multilayer film at a wavelength of 600 nm is preferably 80% or more, and more preferably 90% or more.

[0068] The inorganic layer (I) can be formed by a known physical or chemical vapor deposition method. Specific examples include vacuum vapor deposition, sputtering, ion plating, ion beam mixing, plasma CVD, laser CVD, MO-CVD, thermal CVD, and the like. Physical vapor deposition is preferably used, and among others, vacuum vapor deposition is particularly preferably used. The upper limit of the surface temperature of the layer (X) during the formation of the inorganic layer (I) is preferably 60°C, more preferably 55°C, and even more preferably 50°C. Furthermore, the lower limit of the surface temperature of the layer (X) during the formation of the inorganic layer (I) is preferably, but not specifically limited to, 0°C, more preferably 10°C, and even more preferably 20°C.Before film formation, the exposed surface of layer (X) can be plasma-treated. A known method can be used for the plasma treatment, and atmospheric-pressure plasma treatment is preferred. In atmospheric-pressure plasma treatment, nitrogen, helium, neon, argon, krypton, xenon, radon, or the like is used as the discharge gas. Of these, nitrogen, helium, and argon are preferred, and nitrogen is particularly preferred for cost reduction. <Schutzschicht (P)>

[0069] The multilayer composite film of the present invention comprises the inorganic layer (I) and the protective layer (P) on an exposed surface side of the layer (X) of the multilayer film. The protective layer (P) is preferably directly laminated on the inorganic layer (I). That is, the multilayer composite film preferably has a layered structure in which the layer (X), the inorganic layer (I), and the protective layer (P) are directly laminated in this order. The protective layer (P) has an effect of improving the stability of the gas barrier properties of the multilayer structure by preventing deterioration of the barrier properties during conversion processes such as printing and lamination. The protective layer (P) itself does not need to have gas barrier properties, but preferably has gas barrier properties.

[0070] The protective layer (P) can be made from a resin composition containing a water-soluble resin and at least one metal compound selected from the group consisting of metal alkoxides, metal alkoxide hydrolysates, and metal alkoxide hydrolysis condensation products. Such a metal alkoxide is represented by the general formula: R 1 n M(OR 2 ) m (where M denotes a metal atom, R 1 and R 2 organic groups having a carbon number of 1 to 8, n denotes an integer of 0 or more, m denotes an integer of 1 or more, and n + m denotes a valence of M), and at least one of metal alkoxides, metal alkoxide hydrolysates, or metal alkoxide hydrolysis condensation products can be used. As the metal atom represented in the above general formula: R 1 n M(OR 2 ) m When M is represented by silicon, zirconium, titanium, aluminum, or the like can be used, and silicon is preferably used. These alkoxides can be used by mixing any of them or by mixing alkoxides of two or more different metal atoms in a single solution.

[0071] Specific examples of the organic group R 1 include: alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a t-butyl group, an n-hexyl group, and an n-octyl group; and the like. In addition, specific examples of the organic group R include 2 a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, and the like. These alkyl groups in a single molecule may be the same or different.

[0072] Of the metal alkoxides, alkoxysilanes in which M in the above general formula is silicon (Si) are preferred, and such an alkoxysilane is represented by Si(ORa)4, where Ra denotes a lower alkyl group. Examples of Ra to be used include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and the like, and specific examples of the alkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, and the like. Alkylalkoxysilanes Rb n Si(OR C ) 4-n (n represents an integer of 1, 2, or 3). Examples of Rb and Rc to be used include a methyl group, an ethyl group, and the like, and specific examples of such an alkylalkoxysilane include methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, and the like. Any of these alkoxysilanes and alkylalkoxysilanes can be used singly, or two or more of them can be used by mixing. In addition, it is also possible to use condensation polymerization products of alkoxysilanes, and specific examples include polytetramethoxysilane, polytetraethoxysilane, and the like.

[0073] Two or more of these alkoxides can be used by mixing. In particular, the use of an alkoxysilane and a zirconium alkoxide by mixing sometimes causes an improvement in the toughness, heat resistance, and the like of the protective layer (P) to be obtained. In the present invention, a silane coupling agent can be used together with any of the above alkoxides. As such a silane coupling agent, organoalkoxysilanes containing a known organic reactive group can be used. In particular, organoalkoxysilanes having an epoxy group or an amino group are preferred. Examples thereof include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane. Two or more of these silane coupling agents can be used by mixing.The amount of such a silane coupling agent to be used is within a range of 0.1 to 20 parts by mass based on 100 parts by mass of the above alkoxysilane.

[0074] Examples of the water-soluble resin include: resins having a hydroxyl group such as polyvinyl alcohol and poly-2-hydroxyethyl methacrylate; resins having a carboxyl group such as polyacrylic acid and carboxymethyl cellulose; resins having an amino group such as polyallylamine and polyethyleneimine; resins having an amide group such as polyacrylamide, poly-N,N-dimethylacrylamide and poly-N-isopropylacrylamide; resins having a sulfonic acid group such as polystyrenesulfonic acid and polyvinylsulfonic acid; resins having a polyether group such as polyethylene oxide and polyethylene glycol; polyvinylpyrrolidone; polyoxazoline; and the like.Of the water-soluble resins described above, resins having a hydrogen-bonding group are preferred. Resins having a hydroxyl group, resins having an amide group, resins having a polyether group, polyvinylpyrrolidone, polyoxazoline, and the like are more preferred. Resins having a hydroxyl group are even more preferred. Polyvinyl alcohol is particularly preferred. The polyvinyl alcohol may be one or more compounds selected from the group consisting of copolymers containing vinyl alcohol units, such as ethylene-vinyl alcohol copolymers. Any of these may be used singly, or two or more of them may be used.

[0075] The polyvinyl alcohol can be a homopolymer of vinyl alcohol or a copolymer containing another monomer unit. The degree of saponification is preferably closer to 100 mol% in terms of gas barrier properties, and is usually 90 mol% or more, and preferably 95 mol% or more. The number-average degree of polymerization is usually 50 or more and 5000 or less.

[0076] In the resin composition forming the protective layer (P), the mass ratio of the at least one metal compound selected from the group consisting of metal alkoxides, metal alkoxide hydrolysates, and metal alkoxide hydrolysis condensation products to the water-soluble resin is preferably from 55 / 45 to 95 / 5, more preferably from 65 / 35 to 90 / 10, and even more preferably from 75 / 25 to 85 / 15. When any resin composition of the metal alkoxide hydrolysis condensation product and the water-soluble resin is used as the protective layer (P), a resin composition containing a hydrolysis condensation product of a silane alkoxide and polyvinyl alcohol is particularly preferred.

[0077] When the protective layer (P) is a layer made of the above resin composition, the proportion of the total mass of the metal compound and the water-soluble resin in the protective layer (P) is preferably 80 mass% or more, more preferably 90 mass% or more, even more preferably 95 mass% or more, and particularly preferably 99 mass% or more, and the protective layer (P) may be made substantially only of the metal compound and the water-soluble resin.

[0078] In the present invention, the protective layer (P) composed of the above resin composition is specifically laminated as follows. First, the metal alkoxide, the water-soluble resin, a catalyst for a sol-gel process, acid, water, an organic solvent, and the like are mixed to prepare a coating liquid. In this situation, hydrolysis and condensation polymerization reactions of the metal alkoxide gradually proceed in the coating liquid. Subsequently, the coating liquid is applied to the exposed surface side of the inorganic layer (I) by a conventional method and dried, thus enabling lamination.

[0079] The protective layer (P) may be made of a composition containing a polyurethane resin as a main component. The protective layer (P) containing the polyurethane resin as a main component has a less adverse effect on recyclability and thus tends to enable the production of a high-quality recycled resin. Urethane resins have a polar group of a urethane bond that interacts with the inorganic layer (I) and also flexibility due to the amorphous portion and are therefore preferred because they can prevent damage to the inorganic layer (I) even during dimensional change or application of a bending stress. Such a urethane resin preferably has an acid value within a range of 10 to 60 mg KOH / g.The acid value is more preferably within a range of 15 to 55 mg KOH / g, and even more preferably within a range of 20 to 50 mg KOH / g. The urethane resin having an acid value within the above range causes an improvement in liquid stability when used for an aqueous dispersion and enables uniform lamination of the protective layer (P) on the inorganic layer (I), resulting in good appearance. Furthermore, the urethane resin preferably has a glass transition temperature (Tg) of 80°C or more, and more preferably 90°C or more. A Tg of 80°C or more enables effective inhibition of deterioration of the gas barrier properties of the multilayer composite film in a conversion step.

[0080] In view of improving gas barrier properties, the urethane resin to be used is more preferably a urethane resin containing an aromatic or aromatic / aliphatic diisocyanate component as a main component. In this context, a "component" with respect to a urethane resin refers to a component (a component) constituting the urethane resin. Of these, a urethane resin containing a metaxylylene diisocyanate component is particularly preferably included. The use of the above resin enables an even greater increase in the cohesion of a urethane bond due to the effect of stacking the aromatic rings on top of each other, and as a result, good gas barrier properties are provided.

[0081] In the present invention, the proportion of the aromatic or aromatic / aliphatic diisocyanate in the urethane resin is preferably within a range of 50 mol% or more (from 50 to 100 mol%) in 100 mol% of the polyisocyanate components. The proportion of the total amount of the aromatic or aromatic / aliphatic diisocyanate is preferably from 60 to 100 mol%, more preferably from 70 to 100 mol%, and even more preferably from 80 to 100 mol%. As such a resin, the "TAKELAC® WPB" series commercially available from Mitsui Chemicals, Inc. can be preferably used. A proportion of the total amount of the aromatic or aromatic / aliphatic diisocyanate of 50 mol% or more causes the protective layer (P) itself to tend to have good gas barrier properties.

[0082] In order to improve the affinity for the inorganic layer (I), the urethane resin preferably has a carboxylic acid group (carboxyl group). For introducing a carboxylic acid (carboxylate) group into the urethane resin, for example, a polyol compound having a carboxylic acid group, such as dimethylolpropionic acid and dimethylolbutanoic acid, can be introduced as a polyol component as a copolymerization component. As another example, a carboxylic acid group-containing urethane resin is synthesized and then neutralized with a salt-forming agent to enable the production of a urethane resin in the form of a water dispersion. Specific examples of the salt-forming agent include: ammonia; trialkylamines such as trimethylamine, triethylamine, triisopropylamine, tri-n-propylamine, and tri-n-butylamine; N-alkylmorpholines such as N-methylmorpholine and N-ethylmorpholine; N-dialkylalkanolamines such asN-dimethylethanolamine and N-diethylethanolamine; and the like. Any of these can be used individually, or two or more can be used in combination.

[0083] In the present invention, the protective layer (P) made of the above composition can be formed by applying an aqueous solution or a water dispersion of the urethane resin as a coating liquid to the exposed surface side of the inorganic layer (I) and drying the liquid by a conventional method.

[0084] To further enhance the performance, the protective layer (P) of the present invention may contain crosslinking agents, other polymers, tackifiers, inorganic particles, pigments, dyes and the like.

[0085] As the crosslinking agents, crosslinking agents with self-crosslinking properties, compounds having a plurality of functional groups with reactivity in the molecule, metals with multidentate ligands, and the like can be used. Specific examples include oxazoline group-containing compounds, isocyanate group-containing compounds, epoxy group-containing compounds, carbodiimide group-containing compounds, melamine compounds, urea compounds, zirconium salt compounds, silane coupling agents, and the like, and a plurality of them can be used by mixing if necessary. Of these, oxazoline group-containing compounds, isocyanate group-containing compounds, and epoxy group-containing compounds are preferred in view of handleability.

[0086] Such an oxazoline group-containing compound is not specifically limited as long as the compound has at least two oxazoline groups in the molecule. Examples include: compounds having oxazoline groups, such as 2,2'-bis(2-oxazoline), 2,2'-ethylenebis(4,4'-dimethyl-2-oxazoline), 2,2'-p-phenylenebis(2-oxazoline), and bis(2-oxazolinylcyclohexane) sulfide; oxazoline group-containing polymers; and the like. One or more of these may be used. Of these, oxazoline group-containing polymers are preferred due to handleability.

[0087] The oxazoline group-containing polymer is obtained by polymerizing an addition-polymerizable oxazoline, such as 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, and 2-isopropenyl-2-oxazoline. The oxazoline group-containing polymer may optionally be copolymerized with another monomer. The method of polymerizing the oxazoline group-containing polymer is not specifically limited, and any known polymerization method can be used.

[0088] Examples of commercially available products of the oxazoline group-containing polymer include the EPOCROS series manufactured by Nippon Shokubai Co., Ltd., comprising: the water-soluble "WS-500" and "WS-700"; the emulsion "K-1010E", "K-1020E", "K-1030E", "K-2010E", "K-2020E", and "K-2030E"; and the like.

[0089] Such an isocyanate group-containing compound is not specifically limited as long as the compound has at least two isocyanate groups in the molecule. Examples include: Multifunctional isocyanate compounds such as 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane-2,4'- or -4,4'-diisocyanate, polymethylene polyphenyl diisocyanate, tolidine diisocyanate, 1,4-diisocyanatobutane, hexamethylene diisocyanate, 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4- or 2,4,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3- or 1,4-diisocyanatocyclohexane, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, 4,4'-diisocyanatodicyclohexylmethane, hexahydrotoluene-2,4- or -2,6-diisocyanate, perhydro-2,4'- or -4,4'-diphenylmethane diisocyanate, naphthalene-1,5-diisocyanate, xylylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane and tetramethylxylylene diisocyanate; and modified products thereof.In this context, such a modified product is obtained by modifying a diisocyanate of the multifunctional isocyanate compounds by a known method, and examples include: multifunctional isocyanate compounds having an allophanate group, a biuret group, a carbodiimide group, a uretonimine group, a uretdione group, an isocyanurate group, and the like; and furthermore, adduct-type multifunctional isocyanate compounds obtained by modification with a multifunctional alcohol such as trimethylolpropane. It should be noted that the isocyanate group-containing compound may contain monoisocyanate in a range of 20 mass% or less. Moreover, one or more of these may be used.

[0090] The isocyanate group-containing compound can usually be obtained by reacting a multifunctional isocyanate compound with a monohydric or polyhydric nonionic polyalkylene ether alcohol. Examples of commercially available products of such an aqueous multifunctional isocyanate compound include: Bayhydur 3100, Bayhydur VPLS 2150 / 1, SBU Isocyanate L801, Desmodur N3400, Desmodur VPLS 2102, Desmodur VPLS 2025 / 1, SBU Isocyanate 0772, and Desmodur DN, manufactured by Sumitomo Bayer Urethane Co., Ltd.; Takenate WD720, Takenate WD725, and Takenate WD730, manufactured by Takeda Pharmaceutical Co. Ltd. DURANATE WB40-100, DURANATE WB40-80D, and DURANATE WX-1741, manufactured by Asahi Kasei Corp.; Basonat HW-100 and Basonat LR-9056, manufactured by BASF SE; and the like.

[0091] Such an epoxy group-containing compound is not specifically limited as long as the compound has at least two epoxy groups in the molecule. Examples include: glycidyl ether-type compounds such as bisphenol A diglycidyl ether, bisphenol A β-dimethyl glycidyl ether, bisphenol F diglycidyl ether, tetrahydroxyphenylmethane tetraglycidyl ether, resorcinol diglycidyl ether, brominated bisphenol A diglycidyl ether, chlorinated bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, diglycidyl ethers of bisphenol A-alkylene oxide adducts, novolak glycidyl ether, polyalkylene glycol diglycidyl ether, glycerol triglycidyl ether, pentaerythritol diglycidyl ether, and epoxyurethane resins; glycidyl ether ester-type compounds such as p-oxybenzoic acid glycidyl ether ester; Compounds of the glycidyl ester type, such asDiglycidyl phthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl acrylate and diglycidyl dimer; glycidylamine-type compounds such as glycidylaniline, tetraglycidyldiaminodiphenylmethane, triglycidyl isocyanurate and triglycidylaminophenol; linear aliphatic epoxy resins such as epoxidized polybutadiene and epoxidized soybean oil; Alicyclic epoxy resins such as 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate, 3,4-epoxycyclohexylmethyl(3,4-epoxycyclohexane)carboxylate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, vinylcyclohexene diepoxide, dicyclopentadiene oxide, bis(2,3-epoxycyclopentyl) ether, and limonene dioxide; and the like. One or more of these may be used.

[0092] Examples of the commercially available epoxy group-containing compound as a water-dilutable compound suitable for the present invention include: DENACOL series (EX-313, EM-150, EM-101, etc.) manufactured by Nagase ChemteX Corp.; ADEKA RESIN series (EM-0517, EM-0526, EM-11-50B, EM-051R) manufactured by ADEKA Corp.; and the like.

[0093] Such a melamine compound is not specifically limited as long as the compound has the melamine skeleton in the molecule. Examples of the compound to be used include alkylol melamine derivatives, partially or fully etherified compounds obtained by reacting an alkylol melamine derivative with an alcohol, and mixtures thereof. Examples of the alcohol preferably used for etherification include methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol, and the like. Furthermore, the melamine compound may be either a monomer or a polymer that is a dimer or larger, or a mixture thereof may also be used.

[0094] Examples of commercially available melamine compound products include CYMEL 323, CYMEL 325, CYMEL 327, CYMEL 328, and CYMEL 370, manufactured by Cytec Industries Japan, Inc.

[0095] Such a carbodiimide group-containing compound is not specifically limited as long as the compound has at least two carbodiimide groups in the molecule. Examples include: compounds having carbodiimide groups, such as p-phenylene-bis(2,6-xylylcarbodiimide), tetramethylene-bis(t-butylcarbodiimide), and cyclohexane-1,4-bis(methylene-t-butylcarbodiimide); and polycarbodiimides, which are polymers having carbodiimide groups. One or more of these may be used. Of these, polycarbodiimides are preferred in terms of handleability. Examples of commercially available products of such a polycarbodiimide include the CARBODILITE series from Nisshinbo Chemical Inc. Examples of specific products include: water-soluble "SV-02," "V-02," "V-02-L2," and "V-04"; emulsion "E-01" and "E-02"; organic solution "V-01", "V-03", "V-07" and "V-09"; solventless "V-05"; and the like.

[0096] The content of such a crosslinking agent is preferably from 0.01 to 30 parts by mass based on 100 parts by mass of the polyurethane resin, more preferably from 0.1 to 20 parts by mass, and even more preferably from 0.5 to 10 parts by mass, in view of improving the heat resistance, water resistance, or the like of the coating. A crosslinking agent content of 0.01 parts by mass or more causes an improvement in the coating performance of the protective layer (P), and a content of 80 parts by mass or less sometimes causes an improvement in the coating stability of the protective layer (P), and the like. In view of the recyclability of the multi-layer structure of the present invention, the protective layer (P) preferably does not contain crosslinking agents in some cases.

[0097] Such another polymer and a tackifier are not particularly limited. Examples include: tackifying resins such as polyvinyl acetate, ethylene-vinyl acetate copolymers, polyvinyl chloride, polyvinylidene chloride, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester-maleic anhydride copolymers, styrene-maleic acid resins, styrene-butadiene resins, butadiene resins, acrylonitrile-butadiene resins, poly(meth)acrylonitrile resins, (meth)acrylamide resins, chlorinated polyethylene-based resins, chlorinated polypropylene resins, polyester resins, modified nylon resins, and rosin; phenolic resins; silicone resins; epoxy resins; and the like, and optionally, a plurality of them may be used by blending.It should be noted that these polymers can be used directly in a solid state, whereas in view of maintaining stability in the coating liquid, they are preferably used by processing into an aqueous dispersion.

[0098] Examples of such an inorganic particle include: metal oxides such as magnesium oxide, zinc oxide, and tin oxide; inorganic particles such as calcium carbonate and silicon oxide; inorganic layered compounds such as vermiculite, montmorillonite, hectorite, hydrotalcite, and synthetic mica; and the like. These inorganic particles preferably have an average particle diameter of 0.005 to 10 μm, and more preferably 0.005 to 5 μm, from the viewpoint of stability in the coating liquid. It should be noted that a plurality of them can be used as inorganic particles by mixing. The zinc oxide can be used for ultraviolet shielding, and the tin oxide can be used for antistatic effect.

[0099] Examples of such a pigment and dye include titanium oxide, zinc white, carbon black, and the like, and they can be used in any form of a disperse dye, an acid dye, a cationic dye, a reactive dye, and the like. Various chemicals such as leveling agents, defoamers, boiling inhibitors, pigment dispersants, ultraviolet absorbers, thickeners, weatherability-imparting agents, and flame retardants may be further added to the protective layer (P) of the present invention, if desired.

[0100] When the protective layer (P) contains the urethane resin, the proportion of the urethane resin in the protective layer (P) is preferably 80 mass% or more, more preferably 90 mass% or more, even more preferably 95 mass% or more, and particularly preferably 99 mass% or more, and the protective layer (P) may be made substantially only of the urethane resin. Moreover, when the protective layer (P) contains the urethane resin and the crosslinking agent, the proportion of the total mass of the urethane resin and the crosslinking agent in the protective layer (P) is preferably 80 mass% or more, more preferably 90 mass% or more, even more preferably 95 mass% or more, and particularly preferably 99 mass% or more, and the protective layer (P) may be made substantially only of the urethane resin and the crosslinking agent.

[0101] In view of gas barrier properties, recyclability, and economy, the protective layer (P) in the multilayer composite film preferably has an average thickness of 0.05 µm or more and less than 10 µm. The protective layer (P) more preferably has an average thickness of 0.2 µm or more and less than 4 µm, and even more preferably 0.6 µm or more and less than 1.5 µm.

[0102] In the multi-layer composite film of the present invention, the proportion of the average total thickness of a layer or layers containing the polyethylene-based resin as a main component preferably has a lower limit of 0.75, more preferably 0.80, even more preferably 0.85, and even more preferably 0.88. Increasing the proportion of the average total thickness of a layer or layers containing the polyethylene-based resin as a main component in the multi-layer composite film enables improvement in recyclability. In the multi-layer composite film, the proportion of the average total thickness of a layer or layers containing the polyethylene-based resin as a main component preferably has an upper limit of 0.995, more preferably 0.99, and the upper limit may be 0.98.Examples of the layer or layers containing the polyethylene-based resin as a main component include: the layer (Y) in the case where the adhesive resin (B) is an acid-modified polyethylene; and the layer (Z) in the case where the polyolefin resin (C) is polyethylene.

[0103] In the multi-layer composite film of the present invention, the proportion of the average total thickness of a layer or layers containing a resin having ethylene units as a main component preferably has a lower limit of 0.95, more preferably 0.97, and even more preferably 0.99. An increase in the proportion of the average total thickness of a layer or layers containing a resin having ethylene units as a main component in the multi-layer composite film enables an improvement in recyclability. In the multi-layer composite film, the proportion of the average total thickness of the layer or layers containing the resin having ethylene units as a main component may have an upper limit of, for example, 0.9999.Examples of the layer or layers containing a resin having ethylene units as a main component include, in addition to the layer or layers containing the polyethylene-based resin as a main component described above, the layer (X).

[0104] The multilayer composite film of the present invention does not include a layer containing a resin with a melting point of 200°C or more as a main component and a metal layer with an average thickness of 1 μm or more. Not including a layer containing a resin with a melting point of 200°C or more as a main component and a metal layer with an average thickness of 1 μm or more makes it possible to prevent uneven mixing with other components during melt-molding of the crushed product of the multilayer composite film. It should be noted that the metal layer in this context refers to a layer with continuous and discontinuous surfaces made of metal, such as an aluminum foil.

[0105] The multilayer composite film of the present invention preferably has an oxygen transmission rate (under conditions of 20 °C, 65% relative humidity (RH)) of 0.5 cm 3 / (m 2 · day · atm) or less, measured according to a method described in JIS K 7126-2 (equal pressure method; 2006), more preferably 0.3 cm 3 / (m 2 · day · atm) or less and more preferably 0.1 cm 3 / (m 2 · day · atm) or less. The multilayer composite film with an oxygen transmission rate within the above range exhibits excellent gas barrier properties. <mehrschichtstruktur>

[0106] While the multilayer composite film of the present invention itself can be used as a packaging material having gas barrier properties, the multilayer composite film having at least one resin layer (R) containing a thermoplastic resin (D) as a main component can be used to form a multilayer structure for providing various functions as a packaging material, such as design properties and heat-sealability. The thermoplastic resin (D) is not particularly limited, and examples include: homo- and copolymers of olefins, such as linear low-density polyethylene, low-density polyethylene, medium-density polyethylene, high-density polyethylene, vinyl ester resins, ethylene-propylene copolymers, polypropylene, propylene-α-olefin copolymers (α-olefins having a carbon number of 4 to 20), polybutenes, and polypentenes; polyamides, such as nylon 6 and nylon 6,6; polyesters, such asPolyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrenes; polyvinyl chlorides; polyvinylidene chlorides; acrylic resins; polycarbonates; chlorinated polyethylenes; chlorinated polypropylenes; and the like. Of these, polyolefins are preferred in view of excellent moisture resistance, mechanical properties, economy, heat-sealability, and the like, and polyamides and polyesters are preferred in view of excellent mechanical properties, heat resistance, and the like. In particular, to obtain a multilayer structure with excellent recyclability, the melting point is preferably less than 200°C, and the thermoplastic resin (D) is more preferably of the same type as the above-described polyolefin resin (C), i.e., the polyolefin resin having a melting point of less than 150 °C, more preferably it contains a polyethylene-based resin as a main component, and particularly preferably is a polyethylene-based resin. Accordingly, in order to obtain a multi-layer structure having excellent recyclability, the polyolefin resin (C) and the thermoplastic resin (D) preferably contain a polyethylene-based resin as a main component, and more preferably is a polyethylene-based resin. Such a resin layer (R) may be unstretched, or may be uniaxially or biaxially stretched, or rolled. The resin layer (R) is preferably a biaxially stretched layer in view of improving mechanical strength, and preferably an unstretched layer in view of improving heat sealability.

[0107] Although the method for forming the resin layer (R) is not specifically limited, it is generally formed by melt extrusion using an extruder. As the die, either a ring die or a T-die can be used. The method of uniaxial or biaxial stretching is also not specifically limited, and it can be produced by stretching in the film traveling direction and / or in a direction orthogonal to the traveling direction, that is, in the width direction, using a conventionally known stretching method such as roll-type uniaxial stretching, tube-type simultaneous biaxial stretching, tenter-type sequential biaxial stretching, and tenter-type simultaneous biaxial stretching.The stretching ratio is preferably 8 to 60 times the area ratio in terms of thickness uniformity and mechanical strength of the resulting layer. The area ratio is more preferably 55 times or less, and even more preferably 50 times or less. Furthermore, the area ratio is more preferably 9 times or more. An area ratio of less than 8 times sometimes causes residual stretching unevenness, and an area ratio of more than 60 times sometimes causes the layer to easily crack during stretching.

[0108] The resin layer (R) preferably has an average thickness of 10 to 200 µm in terms of industrial productivity. Specifically, the average thickness in the case of an unstretched layer is more preferably from 10 to 150 µm, and the average thickness in the case of a biaxially stretched layer is more preferably from 10 to 50 µm.

[0109] Furthermore, the multilayer structure of the present invention preferably has an average thickness of 300 µm or less. An average thickness within the above range makes the multilayer structure of the present invention lightweight and flexible, and is therefore preferably used for flexible packaging applications. It also minimizes the amount of resin used in the multilayer structure and reduces environmental impact.

[0110] While the average thickness of each layer in the multi-layer structure of the present invention can be appropriately adjusted depending on the application, in view of enabling prevention of coloring during melt-molding of the crushed product, improving heat stability during melt-molding, and inhibiting generation of hard spots, at least one layer of the layer (Z) or the resin layer (R) preferably contains the polyethylene-based resin as a main component, and the ratio of the total average thickness of the layers containing the polyethylene-based resin as a main component to the average thickness of the multi-layer structure is preferably 0.80 or more, and more preferably 0.85 or more.Further, in terms of improving the gas barrier properties, the ratio is preferably 0.997 or less, more preferably 0.995 or less, and may be 0.993 or less.

[0111] The method of laminating the resin layer (R) to the multilayer composite film of the present invention is not particularly limited, and examples include extrusion lamination, coextrusion lamination, dry lamination, and the like. An adhesive layer may be provided for laminating the resin layer (R) to the multilayer composite film. Moreover, each layer constituting the multilayer structure of the present invention may be optionally laminated via an adhesive layer. It should be noted that no adhesive layers are provided between the layer (X) and the layer (Y) and between the layer (Y) and the layer (Z) of the multilayer film. Such an adhesive layer can be formed by coating with a known adhesive and drying the adhesive.The adhesive is preferably a two-component, polyurethane-based reactive adhesive in which a polyisocyanate component and a polyol component are mixed and reacted. The thickness of the adhesive layer is preferably, but not specifically limited to, from 1 to 5 µm, and more preferably from 2 to 4 µm.

[0112] The layer structure of the multilayer structure of the present invention is not particularly limited, and the following layer structures are preferable, for example, in terms of producing a multilayer structure with excellent recyclability. It should be noted that in the following layer structures, X, Y, Z, I, P, and R denote layer (X), layer (Y), layer (Z), inorganic layer (I), protective layer (P), and layer (R), respectively, and " / " refers to direct lamination, and " / / " refers to lamination via an adhesive layer or direct lamination, while lamination via an adhesive layer is a preferable embodiment. (1) Z / Y / X / I / P / / R (2) R / / Z / Y / X / I / P / / R

[0113] In the above layered structures, layer (X), layer (Y), and layer (Z) are preferably at least uniaxially stretched, and more preferably biaxially stretched. Layer (Z) and layer(s) (R) are preferably made of a polyethylene-based resin, and layer (Y) is preferably made of a maleic anhydride-modified polyethylene-based resin. Moreover, in order to enable recycling of a crushed product obtained by crushing the packaging material and the like of the present invention in the form of a polyethylene-based resin during recycling of the packaging material, the multilayer structure of the present invention preferably has layers containing the polyethylene-based resin as a main component as both outermost layers. That is,when the resin layers (R) are arranged as both outermost layers, the resin layers (R) are preferably layers containing the polyethylene-based resin as a main component, and when the layer (Z) and the resin layer (R) are arranged as both outermost layers, the layer (Z) and the resin layer (R) are preferably layers containing the polyethylene-based resin as a main component.

[0114] The multilayer structure of the present invention may have additional layers other than those described above, as long as the effects of the present invention are not impaired. Examples of such an additional layer include recycled layers. In particular, it is preferable to use a recycled composition containing a recycled material described later from the multilayer structure of the present invention as part or all of the recycled layers. Other examples of such an additional layer include printed layers. Such a printed layer can be incorporated into any position in the multilayer structure of the present invention. An example of the printed layer includes a coating film obtained by coating with a solution containing pigments or dyes and optionally a binder resin, and drying the solution.Examples of the coating method for the printed layer include gravure printing, as well as various coating methods using a wire rod, a spin coater, a die coater, and the like. The average thickness of the printed layer is preferably, but not specifically limited to, 0.5 to 10 μm, and more preferably 1 to 4 μm. It should be noted that, in view of recyclability, the multilayer structure of the present invention preferably does not include a layer containing a resin having a melting point of 200°C or more as a main component and a metal layer having an average thickness of 1 μm or more.

[0115] It is preferable to use a recycled material (waste) obtained by collecting offcuts and defective products generated during the production of the multilayer structure of the present invention. Preferred embodiments of the present invention also include: a method for recycling a multilayer structure, which comprises crushing the multilayer structure of the present invention, followed by melt molding; and a recycled composition containing a recycled material from the multilayer structure of the present invention.

[0116] To recycle the multilayer structure of the present invention, first, a recycled material collected from the multilayer structure of the present invention is crushed. The crushed recycled material may be directly melt-molded to obtain a recycled composition, or may be melt-molded together with other additional components, if desired, to obtain a recycled composition. Preferred examples of such an additional component to be added to the recycled material include polyolefin resins, and polyethylene-based resins are more preferred. The polyolefin resin to be used is of the same type as the above-described polyolefin resin (C) for use in the multilayer film of the present invention. The crushed recycled material can be directly used for the production of molded articles, such asmultilayer structures, or the shredded recycled material can be melt-molded to obtain granules made from the recycled composition, and then the granules can be used to produce molded articles.

[0117] The mass ratio of the resin composition (A) to the polyolefin resin [resin composition (A) / polyolefin resin] in the recycled composition is preferably from 0.01 / 99.99 to 20 / 80. A mass ratio of less than 0.01 / 99.99 may cause a reduction in the utilization rate of the recycled material. Furthermore, a mass ratio of more than 20 / 80 may cause a deterioration in the melt-formability and mechanical properties of the recycled composition. In view of improving the melt-formability and mechanical properties of the recycled composition to be obtained, the mass ratio is more preferably 15 / 85 or less, and even more preferably 10 / 90 or less, and may be 5 / 95 or less.

[0118] The multilayer structure of the present invention has excellent appearance, gas barrier properties and recyclability, and thus can be preferably used as a material for various packaging such as food packaging, pharmaceutical packaging, industrial chemical packaging and agricultural chemical packaging, and in particular, the packaging material comprising the multilayer structure of the present invention is preferably applicable to a packaging material having excellent recyclability. Examples

[0119] The present invention will be described more specifically below with reference to examples, while the present invention is by no means limited by the following examples. Example 1(1) Preparation of an EVOH (a)-containing resin composition (A) for the layer (X)

[0120] An EVOH (a-1) (ethylene unit content of 32 mol%, saponification degree of 99.99 mol%, MFR (190 °C, at a load of 2.16 kg) of 1.6 g / 10 min, melting point of 183 °C, containing 250 ppm of sodium acetate in terms of sodium ions, 30 ppm of phosphoric acid ions in terms of phosphate residues, and 150 ppm of boric acid in terms of boron element, and containing no polyvalent metal ion) and magnesium stearate were melt-kneaded so that a magnesium ion content of 50 ppm was present in the resin composition to be obtained, and thus the resin composition (A) pellets for layer (X) were obtained. The extruder used for melt-kneading was a twin-screw extruder with D (mm) = 25, and co-rotating fully intermeshing screws with L / D = 25 were used. In addition, the resin temperature was set to 220 °C. (2) Adhesive resin (B)-containing resin composition for layer (Y)

[0121] As the adhesive resin (B), a maleic anhydride-modified polyethylene "ADMER" NF518" (MFR (190 °C, at a load of 2.16 kg) of 3.1 g / 10 min, melting point of 121 °C, density of 0.91 g / cm 3 , acid value of 1.8 mg KOH / g), manufactured by Mitsui Chemicals, Inc., was directly used as resin composition granules for the layer (Y). (3) Polyolefin resin (C)-containing resin composition for the layer (Z)

[0122] As the polyolefin resin (C), a low-density polyethylene "INNATE™ TF80" (MFR (190 °C, at a load of 2.16 kg) of 1.6 g / 10 min, melting point of 124 °C, density of 0.926 g / cm 3 ), manufactured by Dow Chemical Co., is used directly as resin composition granules for the layer (Z). (4) Production of a multilayer film

[0123] The above resin composition pellets (1) to (3) were used to produce a multilayer film with an average thickness and a layer structure of (X) / (Y) / (Z) = 4 μm / 4 μm / 32 μm = EVOH 4 / Haft 4 / PE 32 using a coextrusion film forming machine. Each extruder was a single-screw extruder with D (mm) = 30, and a full-flight screw with L / D = 28 and a compression ratio of 3.0 was used. A feed-block laminating T-die with a width of 350 mm was used as the die. The temperature conditions in this situation are shown below. Extrusion temperature of the EVOH (a)-containing resin composition (A): Feed section / Compression section / Measuring section / Adapter = 175 °C / 220 °C / 220 °C / 220 °C Extrusion temperature of the adhesive resin (B)-containing resin composition: Feed section / Compression section / Measuring section / Adapter = 175 °C / 220 °C / 220 °C / 220 °C Extrusion temperature of the polyolefin resin (C)-containing resin composition: Feed section / Compression section / Measuring section / Adapter = 175 °C / 220 °C / 220 °C / 220 °C Nozzle temperature: 220 °C Cooling roller temperature: 80 °C (5) Production of a multilayer composite film

[0124] The surface of layer (X) of the multilayer film obtained in (4) was laminated with a deposited aluminum oxide layer AlOx (inorganic layer (I)) with an average thickness of 50 nm using a known vacuum vapor deposition method. Then, a polyurethane dispersion "TAKELAC™ WPB341" (aqueous dispersion of a polyester urethane resin containing metaxylylene diisocyanate as a monomer component, solid content 30%), manufactured by Mitsui Chemicals, Inc., was diluted with pure water to prepare a coating liquid. The surface of the inorganic layer (I) was coated with the coating liquid using a wire bar to have an average drying thickness of 1 µm, and dried at 100°C for 5 minutes, thereby laminated with a polyurethane resin layer (protective layer (P-1)).In this way, a composite film with an average thickness and a layer structure of (P) / (I) / (X) / (Y) / (Z) = 1 µm / 50 nm / 4 µm / 4 µm / 32 µm = PL 1 / AlOx (50 nm) / EVOH 4 / Haft 4 / PE 32 was prepared. (6) Production of a multilayer structure

[0125] A two-component polyurethane-based reactive adhesive (24 parts by mass of "Takelac™ A-520" and 4 parts by mass of "Takenate™ A-50", manufactured by Mitsui Chemicals Inc.) was mixed with 37 parts by mass of ethyl acetate to prepare an adhesive solution. Subsequently, a corona-treated surface of a polyethylene film (resin layer (R)) having an average thickness of 50 µm was coated with the adhesive solution using a wire bar so that it had an average thickness after drying of 2 µm, and dried at 100 °C for 5 minutes, so that it was laminated with the multilayer composite film obtained in (5), and thus a multilayer structure having an average thickness and a layer structure of (R) / adhesive / (P) / (I) / (X) / (Y) / (Z) = 50 µm / 2 µm / 1 µm / 50 nm / 4 µm / 4 µm / 32 µm was prepared.The adhesive temperature (heat roller temperature) during lamination was 80 °C and then aging was performed at 40 °C for 3 days. (7) Oxygen transmission rate of a multilayer composite film and a multilayer structure

[0126] The oxygen transmission rates of the multilayer composite film and multilayer structure obtained in (5) and (6) were measured according to the method described in JIS K 7126-2 (uniform pressure method; 2006) using layer (Z) as an oxygen supply side. Specifically, the oxygen transmission rate (unit: cm 3 / (m 2 The oxygen transmission rate (O / T) was measured (day / atm) using an oxygen transmission rate analyzer ("MOCON OX-TRAN 2 / 21", manufactured by Modern Control Inc.) under conditions of a temperature of 20 °C, a humidity of 85% relative humidity (RH) on the oxygen supply side, a humidity of 85% relative humidity (RH) on the carrier gas side, an oxygen pressure of 1 atm, and a carrier gas pressure of 1 atm, and evaluated by the following criteria. Nitrogen gas containing 2 vol% hydrogen gas was used as the carrier gas. A measurement result of the multilayer composite film obtained in (5) was set as the oxygen transmission rate before lamination, and a measurement result of the multilayer structure obtained in (6) was set as the oxygen transmission rate after lamination. It should be noted that the case of a rating of D or E was determined as poor gas barrier properties. The results are shown in Table 3. Assessment: Criteria A: Less than 0.1 cm 3 / (m 2 · Day - atm) Width: 0.1 cm 3 / (m 2 · Day - atm) or more and less than 0.3 cm 3 / (m 2 · day · atm) C: 0.3 cm 3 / (m 2 · day · atm) or more and less than 0.5 cm 3 / (m 2 · day · atm) Diameter: 0.5 cm 3 / (m 2 · day · atm) or more and less than 2.0 cm 3 / (m 2 · day · atm) E: 2.0 cm 3 / (m 2 · day · atm) or more (8) Properties of the appearance of the multilayer structure

[0127] The appearance of the multilayer structure obtained in (6) was visually evaluated and assessed using the following criteria. The results are shown in Table 3. Assessment: Criteria Pass: On average, one or fewer lamination defects (delamination) with a diameter of 1 mm or more in 10 cm square Failure: An average of two or more lamination defects (delamination) with a diameter of 1 mm or more in 10 cm square (9) Polyethylene detectability

[0128] The infrared spectrum of the multilayer structure obtained in (6) was measured on both surfaces by a total reflection measurement method and evaluated using the following criteria. The results are shown in Table 3. Assessment: Criteria Passed: Both surfaces were identified as polyethylene Failed: At least one surface was not identified as polyethylene (10) Assessment of the recyclability of the multilayer structure

[0129] The multilayer structure obtained in the above (6) was crushed to a size of 4 mm square or less, and the crushed product was coated with low-density polyethylene (LDPE) "NOVATEC™ LD LJ400" (MFR (190 °C, at a load of 2.16 kg) of 1.5 g / 10 min, melting point of 111 °C, density of 0.921 g / cm 3 ), manufactured by Japan Polyethylene Corp., were blended at a mass ratio (recycled material / low-density polyethylene) of 40 / 60, and monolayer film formation was carried out under the extrusion conditions shown below, so that a monolayer film with an average thickness of 50 μm was obtained. In addition, as a control, a monolayer film with an average thickness of 50 μm was obtained in the same manner using only the low-density polyethylene. The extruder was a single-screw extruder with D (mm) = 20, and a full-flight screw with L / D = 20 and a compression ratio of 3.5 was used. A T-die with a width of 300 mm was used as the die. The average thickness of the monolayer film was adjusted by appropriately changing the screw speeds and the take-up roll speed. The temperature conditions in this situation are shown below. Extrusion temperature: Feed section / Compression section / Measuring section / Adapter = 175 °C / 220 °C / 220 °C / 220 °C Nozzle temperature: 220 °C Cooling roller temperature: 80 °C

[0130] The coloring and defects in the resulting monolayer film were visually assessed and evaluated using the following criteria. It should be noted that E for the defect assessment was determined as insufficient recyclability. The results are shown in Table 3. Assessment criteria for coloring A: Slight degree of color change compared to the control B: Low staining observed compared to the control C: Moderate staining observed compared to the control D: Pronounced staining observed compared to the control E: Pronounced coloration observed and also unevenness compared to the control Assessment criteria for errors A: Amount of hard spots compared to the control almost identical B: Slightly larger amount of small hard spots compared to the control C: Larger number of small hard spots compared to the control D: Larger number of large hard spots compared to the control E: Much larger amount of large hard spots compared to the control Example 2

[0131] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that the deposited aluminum oxide layer was changed to a deposited silicon oxide (SiOx) layer for various measurements and evaluations. The results are shown in Table 3. Example 3

[0132] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that the deposited aluminum oxide layer was changed to a deposited aluminum metal (Al) layer for various types of measurement and evaluation. The results are shown in Table 3. Example 4

[0133] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that the average thickness of the polyurethane resin layer (protective layer (P-1)) was changed to 0.5 µm for various types of measurement and evaluation. The results are shown in Table 3. Example 5

[0134] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that the average thickness of the polyurethane resin layer (protective layer (P-1)) was changed to 2.0 µm for various measurements and evaluations. The results are shown in Table 1. Example 6

[0135] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that a protective layer (P-2) was laminated using a coating liquid prepared by adding 5 parts by mass of the aliphatic hydrophilic polyisocyanate "Bayhydur™ 3100" manufactured by Sumika Covestro Urethane Co., Ltd., based on 100 parts by mass of the solid content of the polyurethane resin to the coating liquid for laminating the polyurethane resin layer (protective layer (P-1)), to perform various types of measurement and evaluation. The results are shown in Table 3. Example 7

[0136] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that a protective layer (P-3) was laminated using a coating liquid obtained by mixing a 3 mass% aqueous polyvinyl alcohol solution with a hydrolyzed solution having a 3 mass% solid content (based on SiO2), the hydrolyzed solution prepared by adding 89.6 g of hydrochloric acid (0.1 N) to 10.4 g of tetraethoxysilane and stirring for 30 minutes for hydrolysis condensation, in a mass ratio of 80 / 20, instead of the coating liquid for laminating the protective layer (P-1), to perform various types of measurement and evaluation. The results are shown in Table 3. Example 8

[0137] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that the average thickness of the deposited alumina layer was changed to 100 nm for various measurements and evaluations. The results are shown in Table 3. Example 9

[0138] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that an EVOH (a-2) (ethylene unit content of 27 mol%, saponification degree of 99.99 mol%, MFR (210 °C, at a load of 2.16 kg) of 4.0 g / 10 min, melting point of 191 °C, containing 220 ppm of sodium acetate in terms of sodium ions, 30 ppm of phosphoric acid ions in terms of phosphate residues, and 150 ppm of boric acid in terms of boron element, and containing no polyvalent metal ion) was used instead of the EVOH (a-1) to perform various types of measurement and evaluation. The results are shown in Table 3. Example 10

[0139] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that an EVOH (a-3) (ethylene unit content of 44 mol%, saponification degree of 99.99 mol%, MFR (190 °C, at a load of 2.16 kg) of 5.7 g / 10 min, melting point of 165 °C, containing 220 ppm of sodium acetate in terms of sodium ions and 30 ppm of phosphoric acid ions in terms of phosphate residues, and containing no polyvalent metal ion) was used instead of the EVOH (a-1) to perform various types of measurement and evaluation. The results are shown in Table 3. Example 11

[0140] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that a mixture (dry blend) of EVOH (a-2) and EVOH (a-3) in a weight ratio of 75 / 25 was used instead of EVOH (a-1) to conduct various types of measurements and evaluations. The results are shown in Table 3. Example 12

[0141] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that an EVOH (a-1A) equivalent to EVOH (a-1) except for a sodium acetate content of 125 ppm in terms of sodium ions was used instead of EVOH (a-1) to perform various types of measurements and evaluations. The results are shown in Table 3. Example 13

[0142] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that an EVOH (a-1B) equivalent to EVOH (a-1) except for a sodium acetate content of 350 ppm in terms of sodium ions was substituted for EVOH (a-1) to conduct various measurements and evaluations. The results are shown in Table 3. Example 14

[0143] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that an EVOH (a-1C) equivalent to EVOH (a-1) except for containing potassium acetate instead of sodium acetate was used instead of EVOH (a-1) to perform various types of measurements and evaluations. The results are shown in Table 3. Examples 15 to 16

[0144] Resin composition granules, multilayer films, multilayer composite films, and multilayer structures were prepared in the same manner as those in Example 1, except that the amount of magnesium stearate to be kneaded with the EVOH (a-1) was changed as shown in Table 1 to perform various types of measurement and evaluation. The results are shown in Table 3. Examples 17 to 18

[0145] Resin composition granules, multilayer films, multilayer composite films, and multilayer structures were prepared in the same manner as those in Example 1, except that magnesium stearate to be kneaded with the EVOH (a-1) was changed to calcium stearate (Example 17) and zinc stearate (Example 18), respectively, for conducting various types of measurement and evaluation. The results are shown in Table 3. Example 19

[0146] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that the average thickness of each layer was changed as shown in Table 1 to perform various types of measurement and evaluation. The results are shown in Table 3. Example 20

[0147] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that instead of the multilayer film in Example 1, a multilayer film having an average thickness and a layer structure of 2 μm / 2 μm / 21 μm = EVOH 2 / Haft 2 / PE 21, which was obtained by preparing a coextruded film having an average thickness and a layer structure of (X) / (Y) / (Z) = 10 μm / 10 μm / 105 μm = EVOH 10 / Haft 10 / PE 105 and stretching it at a stretch ratio of 5 in the longitudinal direction, was used to perform various types of measurement and evaluation. The results are shown in Table 3. Example 21

[0148] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that instead of the multilayer film in Example 1, a multilayer film having an average thickness and a layer structure of 2 μm / 2 μm / 21 μm = EVOH 2 / Haft 2 / PE 21 obtained by preparing a coextrusion film having an average thickness and a layer structure of (X) / (Y) / (Z) = 64 μm / 64 μm / 672 μm = EVOH 64 / Haft 64 / PE 672 using an EVOH (a-4) (ethylene unit content of 44 mol%, saponification degree of 99.99 mol%, modification degree with epoxypropane of 4.6 mol%, MFR (190 °C, at a load of 2.16 kg) of 5.6 g / 10 min, melting point of 122 °C, contains 220 ppm sodium acetate based on sodium ions, 30 ppm phosphoric acid ions based on phosphate residues,150 ppm boric acid based on the element boron and 30 ppm zinc acetate based on zinc ions) and stretching at a stretch ratio of 4 in the longitudinal direction and then at a ratio of 8 in the transverse direction was used instead of EVOH (a-1) to conduct various types of measurements and evaluations. The results are shown in Table 3. Comparative examples 1 to 5

[0149] Resin composition pellets, multilayer films, multilayer composite films, and multilayer structures were prepared in the same manner as those in Examples 1 to 3 and 20 to 21, respectively, except that the protective layer (P-1) was not laminated for performing various types of measurements and evaluations. The results are shown in Table 3. Comparison example 6

[0150] A multilayer composite film and a multilayer structure were manufactured in the same manner as those in Example 1, except that a layer (Z) with an average thickness of 40 μm was used instead of the multilayer film for performing various types of measurement and evaluation. Note that the layer (Z) with an average thickness of 40 μm was formed by extruding only the polyolefin resin (C)-containing resin composition and adjusting the average thickness, instead of simultaneously extruding the resin composition (A), the adhesive resin (B), and the polyolefin resin (C)-containing resin composition in the multilayer film-forming process in Example 1. The results are shown in Table 3. Comparison example 7

[0151] A multilayer composite film and a multilayer structure were manufactured in the same manner as those in Example 1, except that the layer (Z) with an average thickness of 40 μm was used instead of the multilayer film to perform various types of measurement and evaluation, and furthermore, the deposited alumina layer was not laminated. It should be noted that the layer (Z) with an average thickness of 40 μm was formed by extruding only the polyolefin resin (C)-containing resin composition and adjusting the average thickness, instead of simultaneously extruding the resin composition (A), the adhesive resin (B), and the polyolefin resin (C)-containing resin composition in the process of forming the multilayer film in Example 1. The results are shown in Table 3. Comparison example 8

[0152] A resin composition pellet, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that the deposited alumina layer was not laminated to perform various types of measurements and evaluations. The results are shown in Table 3. Comparison example 9

[0153] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that an EVOH (a-1D) equivalent to EVOH (a-1) except for the sodium acetate content of 20 ppm in terms of sodium ions was used instead of EVOH (a-1) for conducting various types of measurements and evaluations. The results are shown in Table 3. Comparison example 10

[0154] A resin composition pellet, a multilayer film, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that an EVOH (a-1E) equivalent to EVOH (a-1) except for the sodium acetate content of 550 ppm in terms of sodium ions was used instead of EVOH (a-1) to perform various types of measurements and evaluations. The results are shown in Table 3. Reference example 1

[0155] A multilayer composite film and a multilayer structure were prepared in the same manner as those in Example 1, except that a biaxially stretched polyethylene terephthalate (PET) film "Lumirror™ P60" (melting point of 256 °C, average thickness of 12 µm) manufactured by Toray Industries, Inc., and except that the protective layer (P-1) was not laminated, was used instead of the multilayer film to perform various types of measurements and evaluations. The results are shown in Table 3. Reference example 2

[0156] A resin composition pellet, a multilayer composite film, and a multilayer structure were prepared in the same manner as those in Example 1, except that the maleic anhydride-modified polypropylene "ADMER™ QF551" (MFR (230 °C, at a load of 2.16 kg) of 5.7 g / 10 min, melting point of 144 °C, density of 0.89 g / cm 3 ), manufactured by Mitsui Chemicals, Inc., as the adhesive resin and the polypropylene "NOVATEC™ PP EA7AD" (MFR (230 °C, at a load of 2.16 kg) of 1.4 g / 10 min, melting point of 161 °C, density of 0.90 g / cm 3 ), manufactured by Japan Polypropylene Corp., was used as the polyolefin resin and the protective layer (P-1) was not laminated. The results are shown in Table 3. [Table 1] (Part 1) Multilayer composite film Protective layer (P) Inorganic layer (I) Resin composition (A) EVOH (a) alkali metal ion(b) Polyvalent metal ion (c) type thickness type thickness type Ethylene unit content Melting point Type Salary Type Salary - µm - nm - Mol-% °C - ppm - ppm Example 1 P-1 1,0 AlOx 50 a-1 32 183 N / a 250 Mg 50 Example 2 P-1 1,0 SiOx 50 a-1 32 183 N / a 250 Mg 50 Example 3 P-1 1,0 Al 50 a-1 32 183 N / a 250 Mg 50 Example 4 P-1 0,5 AlOx 50 a-1 32 183 N / a 250 Mg 50 Example 5 P-1 2,0 AlOx 50 a-1 32 183 N / a 250 Mg 50 Example 6 P-2 1,0 AlOx 50 a-1 32 183 N / a 250 Mg 50 Example 7 P-3 1,0 AlOx 50 a-1 32 183 N / a 250 Mg 50 Example 8 P-1 1,0 Al 100 a-1 32 183 N / a 250 Mg 50 Example 9 P-1 1,0 AlOx 50 a-2 27 191 N / a 220 Mg 50 Example10 P-1 1,0 AlOx 50 a-3 44 165 N / a 220 Mg 50 Example11 P-1 1,0 AlOx 50 a-2a-3 2744 191165 N / a 250 Mg 50 Example12 P-1 1,0 AlOx 50 a-1A 32 183 N / a 125 Mg 50 [Table 1] (Part 2) Multilayer composite film Layer structure, average thickness Stretch ratio of the multilayer filmMD x TD Average thickness ratio of the PE resin layer Average thickness ratio of the ethylene unit-containing resin layer µm - - - Example 1 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 2 PL1 / SiOx (50nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 3 PL1 / Al (50nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 4 PL0.5 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,89 0,99 Example 5 PL2 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,86 0,95 Example 6 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 7 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 8 PL1 / Al (100nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 9 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 10 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 11 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 12 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 [Table 1] Continued (Part 1) Multilayer composite film Protective layer (P) Inorganic layer (I) Resin composition (A) EVOH (a) alkali metal ion(b) Polyvalent metal ion(c) type thickness type thickness type Ethylene unit content Melting point Type Salary Type Salary - µm - nm - Mol-% °C - ppm - ppm Example 13 P-1 1,0 AlOx 50 a-1B 32 183 N / a 350 Mg 50 Example 14 P-1 1,0 AlOx 50 a-1C 32 183 K 250 Mg 50 Example 15 P-1 1,0 AlOx 50 a-1 32 183 N / a 250 - - Example 16 P-1 1,0 AlOx 50 a-1 32 183 N / a 250 Mg 250 Example 17 P-1 1,0 AlOx 50 a-1 32 183 N / a 250 Ca 50 Example 18 P-1 1,0 AlOx 50 a-1 32 183 N / a 250 Zn 50 Example 19 P-1 1,0 AlOx 50 a-1 32 183 N / a 250 Mg 50 Example 20 P-1 1,0 AlOx 50 a-1 32 183 N / a 250 Mg 50 Example 21 P-1 1,0 AlOx 50 a-4 44 122 N / a 220 MgZn 5030 [Table 1] Continued (Part 2) Multilayer composite film Layer structure, average thickness Stretch ratio of the multilayer filmMD x TD Average thickness ratio of the PE resin layer Average thickness ratio of the ethylene unit-containing resin layer µm - - - Example 13 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 14 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 15 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 16 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 17 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 18 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Example 19 PL1 / AlOx (50 nm)IEVOH 1 0 / Haft5 / PE25 Unstretched 0,73 0,98 Example 20 PL1 / AlOx (50 nm)IEVOH2 / Haft2 / PE21 5x1 0,88 0,96 Example 21 PL1 / AlOx (50 nm)IEVOH2 / Haft2 / PE21 4x8 0,88 0,96 [Table 2] Multilayer composite film Protective layer (P) Inorganic layer (I) Resin composition (A) EVOH (a) alkali metal ion(b) Polyvalent metal ion(c) type thickness type thickness type Ethylene unit content Melting point Type Salary Type Salary - µm - nm - Mol-% °C - ppm - ppm Comparison example 1 - - AlOx 50 a-1 32 183 N / a 250 Mg 50 Comparison example 2 - - SiOx 50 a-1 32 183 N / a 250 Mg 50 Comparison example 3 - - Al 50 a-1 32 183 N / a 250 Mg 50 Comparison example 4 - - AlOx 50 a-1 32 183 N / a 250 Mg 50 Comparison example 5 - - AlOx 50 a-4 44 122 N / a 220 MgZn 5030 Comparison example 6 P-1 1,0 AlOx 50 - - - - - - - Comparison example 7 P-1 1,0 - - - - - - - - - Comparison example 8 P-1 1,0 - - a-1 32 183 N / a 250 Mg 50 Comparison example 9 P-1 1,0 AlOx 50 a-1D 32 183 N / a 20 Mg 50 Comparison example 10 P-1 1,0 AlOx 50 a-1E 32 183 N / a 550 Mg 50 Reference example 1 - - Al 50 OPET Reference example 2 - - Al 50 a-1 32 183 N / a 250 Mg 50 [Table 2] (continued) Multilayer composite film Layer structure, average thickness Stretch ratio of the multilayer filmMD x TD Average thickness ratio of the PE resin layer Average thickness ratio of the ethylene unit-containing resin layer µm - - - Comparison example 1 AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Comparison example 2 SiOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Comparison example 3 Al (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Comparison example 4 AlOx (50 nm)IEVOH2 / Haft2 / PE21 5x1 0,88 0,96 Comparison example 5 AlOx (50 nm)IEVOH2 / Haft2 / PE21 4x8 0,88 0,96 Comparison example 6 PL1 / AlOx (50 nm) / PE40 Unstretched 0,98 0,98 Comparison example 7 PL1 / PE40 Unstretched 0,98 0,98 Comparison example 8 PL1 / EVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Comparison example 9 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Comparison example 10 PL1 / AlOx (50 nm)IEVOH4 / Haft4 / PE32 Unstretched 0,88 0,98 Reference example 1 Al (50 nm) / PET12 Unstretched 0,00 0,00 Reference example 2 Al (50 nm)IEVOH4 / Haft4 / PP32 Unstretched 0,00 0,00 [Table 3] Evaluation Oxygen transmission rate Look PE recording Recycling capacity Before lamination After lamination coloring Mistake cm 3 / (m 2 · Tag · atm) - - - - Example 1 B B Passed Passed B B Example 2 B B Passed Passed B B Example 3 B B Passed Passed D B Example 4 B C Passed Passed B A Example 5 B B Passed Passed C C Example 6 B B Passed Passed B C Example 7 A B Passed Passed C C Example 8 A A Passed Passed E C Example 9 A A Passed Passed C C Example 10 B C Passed Passed A A Example 11 A A Passed Passed C B Example 12 B B Passed Passed B C Example 13 B B Passed Passed C C Example 14 B B Passed Passed A B Example 15 B B Passed Passed A D Example 16 B B Passed Passed D C Example 17 B B Passed Passed B C Example 18 B B Passed Passed B C Example 19 A A Passed Passed C C Example 20 A B Passed Passed B B Example 21 A A Passed Passed B B Comparison example 1 C E Passed Passed B A Comparison example 2 C E Passed Passed B A Comparison example 3 B D Passed Passed D A Comparison example 4 B D Passed Passed B A Comparison example 5 B E Passed Passed B A Comparison example 6 D E Passed Passed A A Comparison example 7 E E Passed Passed A A Comparison example 8 E E Passed Passed A A Comparison example 9 B B Passed Passed A E Comparison example 10 B B Passed Passed D E Reference example 1 C C Passed Failed D E Reference example 2 B C Passed Failed D B

[0157] From Reference Example 1, it is clear that the multilayer laminated film having an aluminum layer deposited on PET does not cause deterioration in gas barrier properties during lamination even without the protective layer (P). Furthermore, it is clear from Reference Example 2 that the resin having a melting point of 150°C or more used as the layer (Y) and the layer (Z) does not cause deterioration in gas barrier properties during lamination even without the protective layer (P). That is, it is clear that deterioration in gas barrier properties during lamination is a problem specific to the case where the multilayer laminated film of the present invention does not have the protective layer (P). QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2020 / 071513 A1

[0004] WO 2021 / 261560 A1

[0004] Cited non-patent literature

[0000] JIS K7210 (2014)

[0027] JIS K7210 (2014

[0054] JIS K 7126-2

[0126] < / mehrschichtstruktur> < / mehrschichtfolie> < / borverbindung>

Claims

[1] A multi-layer composite film comprising: a layer (X); a layer (Y); and a layer (Z) which are adjacently laminated in this order, wherein the layer (X) is an outermost layer and comprises an inorganic layer (I) and a protective layer (P) on an exposed surface side, wherein the layer (X) is made of a resin composition (A) containing an ethylene-vinyl alcohol copolymer (a) having an ethylene unit content of 20 to 50 mol% and a saponification degree of 90 mol% or more as a main component, the layer (Y) contains an adhesive resin (B) having a melting point of less than 150 °C as a main component, the layer (Z) contains a polyolefin resin (C) having a melting point of less than 150 °C as a main component, the resin composition (A) contains from 40 to 500 ppm of alkali metal ion (b), and the multi-layer composite film does not comprise a layer containing a resin having a melting point of 200 °C or more as a main component and does not comprise a metal layer having an average thickness of 1 µm or more. [2] The multi-layer composite film according to claim 1, wherein the protective layer (P), the inorganic layer (I) and the layer (X) are adjacently laminated in this order. [3] The multi-layer composite film according to claim 1 or 2, wherein the adhesive resin (B) is acid-modified polyethylene. [4] The multilayer composite film according to any one of claims 1 to 3, wherein the polyolefin resin (C) is polyethylene. [5] The multi-layer composite film according to any one of claims 1 to 4, wherein the inorganic layer (I) is a deposited metal layer containing aluminum as a main component or a deposited inorganic oxide layer containing aluminum oxide or silicon oxide as a main component. [6] Multilayer composite film according to one of claims 1 to 5, wherein the protective layer (P) contains a water-soluble resin and at least one metal compound selected from the group consisting of metal alkoxides, metal alkoxide hydrolysates and metal alkoxide hydrolysis condensation products. [7] The multi-layer composite film according to any one of claims 1 to 5, wherein the protective layer (P) contains a polyurethane resin as a main component. [8] The multi-layer composite film according to any one of claims 1 to 7, wherein the resin composition (A) contains 10 ppm or more and 300 ppm or less of at least one polyvalent metal ion (c) selected from the group consisting of magnesium ion, calcium ion and zinc ion. [9] The multilayer composite film according to any one of claims 1 to 8, wherein the ethylene-vinyl alcohol copolymer (a) is an ethylene-vinyl alcohol copolymer (a') having a melting point of less than 150°C. [10] The multilayer composite film according to claim 9, wherein the ethylene-vinyl alcohol copolymer (a') has a modifying group containing a primary hydroxyl group represented by the following general formula (I): [Chem. 1]wherein X is a hydrogen atom, a methyl group or a group substituted by R 2 -OH, R 1 and R 2 each independently represents a single bond, an alkylene group having a carbon number of 1 to 9 or an alkyleneoxy group having a carbon number of 1 to 9, and the alkylene group and the alkyleneoxy group optionally contain a hydroxyl group, an alkoxy group or a halogen atom. [11] Multilayer composite film according to claim 10, wherein in the general formula (I) R 1 is a methylmethyleneoxy group and X is a hydrogen atom. [12] The multi-layer composite film according to claim 10 or 11, wherein in the ethylene-vinyl alcohol copolymer (a'), a content of the modifying group containing a primary hydroxyl group is 2 mol% or more and less than 20 mol%. [13] A multilayer composite film according to any one of claims 1 to 12, wherein the multilayer film is not substantially stretched. [14] A multilayer composite film according to any one of claims 1 to 12, wherein the multilayer film is substantially only uniaxially stretched by 3 times or more and less than 12 times. [15] The multilayer composite film according to any one of claims 1 to 12, wherein the multilayer film is biaxially stretched by 3 times or more and less than 12 times in each direction. [16] The multi-layer composite film according to any one of claims 1 to 15, wherein a ratio of an average total thickness of a layer or layers containing a polyethylene-based resin as a main component is 0.75 or more. [17] The multi-layer composite film according to any one of claims 1 to 16, wherein a ratio of an average total thickness of a layer or layers containing a resin having ethylene units as a main component is 0.95 or more. [18] Multilayer composite film according to any one of claims 1 to 17, wherein the multilayer film has an oxygen transmission rate under conditions of 20 °C, 65% relative humidity (RH), of 0.5 cm 3 / (m 2 · day · atm) or less, measured according to a method described in JIS K 7126-2: 2006. [19] A multi-layer structure obtained by laminating the multi-layer composite film according to any one of claims 1 to 18 and at least one resin layer (R) containing a thermoplastic resin (D) as a main component. [20] A multilayer structure according to claim 19, wherein the thermoplastic resin (D) is polyethylene. [21] Packaging material comprising the multilayer structure according to claim 19 or 20. [22] A recycled composition comprising a recycled material from the multilayer structure of claim 19 or 20. [23] A method of recycling a multilayer structure, the method comprising comminuting the multilayer structure according to claim 19 or 20, followed by melt forming.