Multilayer structure

Abstract

The following is provided as a multilayer structure that has excellent transparency and impact resistance and is easy to recycle.　A multilayer structure that has a polar group-containing resin layer (A) comprising a polar group-containing resin (a) that comprises an ethylene-vinyl alcohol copolymer and / or polyamide, a polyolefin resin layer (B) comprising a polyolefin resin (b1) and a compatibilizer (b2), and an adhesive resin layer (C), wherein the melt flow rate of the compatibilizer (b2) is 600 g / 10 min (190℃, load 2160 g) or less, and the content of the compatibilizer (b2) is 10-200 parts by mass with respect to 100 parts by mass of the polar group-containing resin (a).

Description

multilayer structure The present invention relates to a multilayer structure, and more particularly to a multilayer structure that has excellent transparency and impact resistance, and is easily recyclable. Polar group-containing resins such as ethylene-vinyl alcohol copolymers (hereinafter sometimes referred to as "EVOH") and polyamide resins (hereinafter sometimes referred to as "PA resins") are generally It is used by being formed into multilayer structures such as packaging films for foods and containers using a molding method. In order to reduce the amount of plastic packaging waste, we collected scraps generated during the manufacturing process of multilayer structures using these polar group-containing resins and polyolefin resins, and pulverized them into fine particles. A recycling technique is known in which a resin composition obtained by melting and kneading materials is granulated / molded and recycled as a regrind layer of a multilayer structure. However, the polar group-containing resin and polyolefin resin in the resin composition obtained in this way are difficult to miscible with each other and have poor recyclability. Addition of compatibilizers during the process is practiced. However, it has been difficult to appropriately select the timing and required amount of the compatibilizer in the recycling process. In order to solve this problem, for example, Patent Document 1 discloses a) at least one layer containing a polyolefin component, wherein the polyolefin component is i) an ethylene homopolymer, an ethylene copolymer, a polypropylene homopolymer, a polypropylene copolymer, and combinations thereof; ii) 0 to 35 weight percent of a functional polymer component; and iii) a melt viscosity of 200,000 cP or less. 177°C) and 1 to 35 weight percent of a compatibilizer component comprising an anhydride- and / or carboxylic acid-functionalized ethylene / alpha-olefin interpolymer having a density of 0.855 g / cc to 0.94 g / cc. b) at least one tie layer comprising a maleic anhydride grafted polymer having a melt index of less than 50 dg / min, the tie layer not containing said compatibilizer component; c) and at least one polar layer comprising a polar polymer. Special Publication No. 2018-502743 According to Patent Document 1, it is stated that the recyclability of the multilayer structure can be improved because the multilayer structure contains a compatibilizing agent in advance, but the transparency and impact resistance of the multilayer structure itself may be improved. There was an issue of decreased sexual performance. The present inventor speculated that the above problem was caused by the compatibilizer added to improve recyclability. Therefore, the present invention provides a multilayer structure that is easy to recycle and in which deterioration in transparency and impact resistance of the multilayer structure itself is suppressed. As a result of extensive research in view of the above circumstances, the present inventor has determined that a polyolefin resin layer containing a polyolefin resin and a compatibilizer having a specific melt flow rate (MFR) can be formed into a multilayer structure including a polar group-containing resin layer. It has been discovered that the above problems can be solved by providing the device on the body. That is, the present invention provides the following [1] to

[10] . [1] A polar group-containing resin layer (A) containing a polar group-containing resin (a) containing an ethylene-vinyl alcohol copolymer and / or polyamide, A polyolefin resin layer (B) containing a polyolefin resin (b1) and a compatibilizer (b2), and Has an adhesive resin layer (C), The melt flow rate of the compatibilizer (b2) is 600 g / 10 minutes (190°C, load 2160 g) or less, A multilayer structure in which the content of the compatibilizer (b2) is 10 to 200 parts by mass based on 100 parts by mass of the polar group-containing resin (a). [2] The multilayer structure according to [1], wherein the content of the compatibilizer (b2) is 1 to 99% by mass based on the polyolefin resin layer (B). [3] The multilayer structure according to [1] or [2], wherein the compatibilizer (b2) has a melt flow rate of 0.1 to 100 g / 10 minutes (190° C., load 2160 g). [4] The multilayer structure according to any one of [1] to [3], wherein the compatibilizer (b2) is a maleic anhydride-modified ethylene-butene copolymer. [5] The multilayer structure according to any one of [1] to [3], wherein the compatibilizer (b2) is an ethylene-vinyl acetate copolymer. [6] The multilayer according to any one of [1] to [5], wherein the melt flow rate ratio (b1 / b2) of the polyolefin resin (b1) and the compatibilizer (b2) is 0.003 to 300. Structure. [7] The multilayer structure according to any one of [1] to [6], wherein the polyolefin resin layer (B) contains less than 5% by mass of an inorganic filler as an optional component. [8] [1] The polyolefin resin (b1) is one or more polyethylenes selected from the group consisting of linear low density polyethylene, low density polyethylene, very low density polyethylene, medium density polyethylene, and high density polyethylene. ] to [7]. The multilayer structure according to any one of [7]. [9] The multilayer structure according to any one of [1] to [8], wherein the multilayer structure further includes a base layer (D1).

[10] A polar group-containing resin (a) containing an ethylene-vinyl alcohol copolymer and / or polyamide, a polyolefin resin (b1), a compatibilizer (b2), and an adhesive resin, the compatibilizer (b2) has a melt flow rate of 600 g / 10 min (190° C., load 2160 g) or less, and the content of the compatibilizer (b2) is 10 to 200 parts by mass based on 100 parts by mass of the polar group-containing resin (a). A resin composition. The multilayer structure of the present invention includes a polar group-containing resin layer (A) containing a polar group-containing resin (a), and a polyolefin resin layer (B) containing a polyolefin resin (b1) and a compatibilizer (b2). , has an adhesive resin layer (C), the melt flow rate of the compatibilizer (b2) is 600 g / 10 minutes (190 ° C., load 2160 g) or less, and the content of the compatibilizer (b2) is When the amount is 10 to 200 parts by mass based on 100 parts by mass of the polar group-containing resin (a), excellent transparency and impact resistance are achieved. Hereinafter, embodiments for carrying out the present invention will be specifically described, but the present invention is not limited thereto. In the present invention, "x and / or y (x, y are arbitrary structures or components)" means three combinations: x only, y only, and x and y. In addition, in the present invention, when expressed as "X to Y" (X, Y are arbitrary numbers), unless otherwise specified, it means "more than or equal to X and less than or equal to Y", and also "preferably larger than X" or "preferably It also includes the meaning of "less than Y". In addition, when expressed as "more than or equal to X" (X is an arbitrary number) or "less than or equal to Y" (where Y is an arbitrary number), it also means that "it is preferably greater than X" or "it is preferably less than Y". It also includes meaning. The multilayer structure of the present invention includes a polar group-containing resin layer (A) containing a polar group-containing resin (a), and a polyolefin resin layer (B) containing a polyolefin resin (b1) and a compatibilizer (b2). , has an adhesive resin layer (C), the melt flow rate of the compatibilizer (b2) is 600 g / 10 min (190°C, load 2160 g) or less, and the content of the compatibilizer (b2) is a polar group. The amount is 10 to 200 parts by mass based on 100 parts by mass of the resin (a). Each configuration will be explained below. [Polar group-containing resin layer (A)] The polar group-containing resin layer (A) constituting the multilayer structure of the present invention contains a polar group-containing resin (a). The polar group-containing resin (a) is not particularly limited as long as it is a resin containing a polar group, but is preferably a thermoplastic resin containing a polar group. The polar group-containing resin (a) contains EVOH and / or PA resin, more preferably EVOH and / or PA resin, and more preferably EVOH. The content of the polar group-containing resin (a) in the polar group-containing resin layer (A) is not particularly limited, such as 1% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more. However, it is preferable that the polar group-containing resin (a) is the main component. The content of the polar group-containing resin (a) in the polar group-containing resin layer (A) is more preferably 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more. , more preferably 95% by mass or more and 100% by mass. The polar group-containing resin layer (A) contains known plasticizers, lubricants, heat stabilizers, light stabilizers, ultraviolet absorbers, antioxidants, within a range that does not impede the effects of the present invention (for example, less than 30% by mass), Additives such as crystal nucleating agents, coloring agents, antistatic agents, surfactants, antibacterial agents, desiccants, oxygen absorbers, anti-blocking agents, etc. may be blended, and polar group-containing resins may be blended. good. These can be used alone or in combination of two or more. (EVOH) EVOH used as the polar group-containing resin (a) is usually a resin obtained by saponifying an ethylene-vinyl ester copolymer, which is a copolymer of ethylene and a vinyl ester monomer, and is non-aqueous. It is a thermoplastic resin. As the vinyl ester monomer, vinyl acetate is generally used from an economical point of view. The copolymerization method of ethylene and vinyl ester monomer can be carried out using any known polymerization method, such as solution polymerization, suspension polymerization, emulsion polymerization, etc., and generally methanol is used as a solvent. Solution polymerization is used. The obtained ethylene-vinyl ester copolymer may be saponified by a known method. The EVOH produced in this way mainly contains ethylene structural units and vinyl alcohol structural units, and if the degree of saponification is less than 100 mol%, it contains a small amount of vinyl ester structural units that remain as unsaponified parts. . In the present invention, "mainly" refers to the most abundant component in the object, and usually it is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably It may be 70% by mass or more, particularly preferably 80% by mass or more, particularly preferably 90% by mass or more, and 100% by mass. As the vinyl ester monomer, vinyl acetate is typically used because of its market availability and good efficiency in treating impurities during production. Examples of other vinyl ester monomers include vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl versatate, etc. Examples include aliphatic vinyl esters and aromatic vinyl esters such as vinyl benzoate, and aliphatic vinyl esters having usually 3 to 20 carbon atoms, preferably 4 to 10 carbon atoms, and particularly preferably 4 to 7 carbon atoms are used. Can be done. These can be used alone or in combination of two or more. EVOH is usually made from petroleum-derived raw materials such as naphtha, but it is also made from raw materials derived from natural gas such as shale gas, sugars and starches contained in sugar cane, sugar beet, corn, potatoes, etc., or rice. Plant-derived raw materials purified from components such as cellulose contained in plants such as , wheat, and millet may also be used. The content of the ethylene structural unit in EVOH can be controlled by the pressure of ethylene when copolymerizing the vinyl ester monomer and ethylene, and is preferably 20 to 60 mol%. More preferably 25 to 50 mol%, particularly preferably 25 to 35 mol%. If this content is too low, the gas barrier properties and melt moldability under high humidity tend to decrease, while if it is too high, the gas barrier properties tend to decrease. Note that the content of the ethylene structural unit can be measured based on ISO14663, for example. In addition, the degree of saponification of the vinyl ester component in EVOH is determined by the amount, temperature, and time of saponification catalyst (usually an alkaline catalyst such as sodium hydroxide is used) when saponifying the ethylene-vinyl ester copolymer. It can be controlled by, for example, 90 to 100 mol%, preferably 95 to 100 mol%, particularly preferably 99 to 100 mol%. When the degree of saponification is low, gas barrier properties, thermal stability, moisture resistance, etc. tend to decrease. The degree of saponification of EVOH can be measured based on JIS K6726 (EVOH is used as a solution uniformly dissolved in a water / methanol solvent). The melt flow rate (MFR, based on JISK7210) (210°C, load 2160 g) of EVOH is usually 0.5 to 100 g / 10 minutes, preferably 1 to 50 g / 10 minutes, particularly preferably 3 to 35 g / 10 It's a minute. If the MFR is too large, the moldability tends to become unstable, and if the MFR is too small, the viscosity tends to become too high, making melt extrusion difficult. MFR is an index of the degree of polymerization of EVOH, and can be adjusted by the amount of polymerization initiator and the amount of solvent when copolymerizing ethylene and vinyl ester monomer. Furthermore, EVOH may further contain a structural unit derived from the comonomer shown below within a range that does not impede the effects of the present invention (for example, 10 mol% or less of EVOH). Comonomers include olefins such as propylene, 1-butene, and isobutene; 3-buten-1-ol, 3-buten-1,2-diol, 4-penten-1-ol, 5-hexene-1,2- Hydroxy group-containing α-olefins such as diols and derivatives such as esterification products and acylation products thereof; Hydroxyalkylvinylidenes such as 2-methylenepropane-1,3-diol and 3-methylenepentane-1,5-diol; 1 , 3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane, 1,3-dibutyryloxy-2-methylenepropane and other hydroxyalkylvinylidene diacetates; acrylic acid, methacrylic acid, Unsaturated acids or salts thereof such as crotonic acid, phthalic acid (anhydride), maleic acid (anhydride), itaconic acid (anhydride), or mono- or dialkyl esters in which the alkyl group has 1 to 18 carbon atoms; acrylamide, alkyl group Acrylamides such as N-alkylacrylamide having 1 to 18 carbon atoms, N,N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or its salt, acrylamidepropyldimethylamine or its acid salt or its quaternary salt; methacrylamide , N-alkylmethacrylamide whose alkyl group has 1 to 18 carbon atoms, N,N-dimethylmethacrylamide, 2-methacrylamidopropanesulfonic acid or its salt, methacrylamidepropyldimethylamine or its acid salt, or its quaternary Methacrylamides such as salts; N-vinylamides such as N-vinylpyrrolidone, N-vinylformamide, and N-vinylacetamide; vinyl cyanides such as acrylonitrile and methacrylnitrile; Vinyl ethers such as certain alkyl vinyl ethers, hydroxyalkyl vinyl ethers, and alkoxyalkyl vinyl ethers; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, and vinyl bromide; vinyl silanes such as trimethoxyvinylsilane; acetic acid Halogenated allyl compounds such as allyl and allyl chloride; Allyl alcohols such as allyl alcohol and dimethoxyallyl alcohol; Trimethyl-(3-acrylamido-3-dimethylpropyl)-ammonium chloride, acrylamide-2-methylpropanesulfonic acid, etc. Examples include comonomers. These can be used alone or in combination of two or more. In particular, EVOH copolymerized with hydroxy group-containing α-olefins, that is, EVOH having a hydroxyl group in the side chain, is preferable because it has good secondary moldability while maintaining gas barrier properties. It is an EVOH having a primary hydroxyl group, and particularly preferably an EVOH having a 1,2-diol structure in its side chain. For EVOH having a primary hydroxyl group in the side chain, the content of structural units derived from the monomer having the primary hydroxyl group is usually 0.1 to 20 mol%, more preferably 0.5 to 15 mol%, particularly is preferably 1 to 10 mol%. Furthermore, the EVOH may be one that has been "post-modified" such as urethanation, acetalization, cyanoethylation, or oxyalkylenation. Further, the EVOH may be a mixture of two or more types of EVOH, such as those having different degrees of saponification, those having different degrees of polymerization, and those having different copolymerization components. (PA resin) The PA resin used as the polar group-containing resin (a) is not particularly limited, and common polyamide resins include, for example, polycapramide (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), and polyamide. Examples include homopolymers such as -ω-aminononanoic acid (nylon 9), polyundecaneamide (nylon 11), and polylauryllactam (nylon 12). Copolymerized polyamide resins include polyethylenediamine adipamide (nylon 26), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), and polyhexamethylene sebacamide (nylon 610). , polyhexamethylene dodecamide (nylon 612), polyoctamethylene adipamide (nylon 86), polydecamethylene adipamide (nylon 108), caprolactam / lauryllactam copolymer (nylon 6 / 12), caprolactam / ω - Aminononanoic acid copolymer (nylon 6 / 9), caprolactam / hexamethylene diammonium adipate copolymer (nylon 6 / 66), lauryl lactam / hexamethylene diammonium adipate copolymer (nylon 12 / 66), ethylenediamine azide Pamide / hexamethylene diammonium adipate copolymer (nylon 26 / 66), caprolactam / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer (nylon 66 / 610), ethylene ammonium adipate / hexamethylene diammonium Aliphatic polyamides such as adipate / hexamethylene diammonium sebacate copolymer (nylon 6 / 66 / 610), polyhexamethylene isophthalamide, polyhexamethylene terephthalamide, polymethaxylylene adipamide, hexamethylene isophthalamide / Terephthalamide copolymers, aromatic polyamides such as poly-p-phenylene terephthalamide and poly-p-phenylene-3,4'-diphenyl ether terephthalamide, amorphous polyamides, and these polyamide resins are combined with methylenebenzylamine, meth Examples include those modified with aromatic amines such as xylene diamine, metaxylylene diammonium adipate, and the like. Alternatively, these terminal-modified polyamide resins may be used, and terminal-modified polyamide resins are preferred. These PA resins can be used alone or in combination of two or more. The melting point of the PA resin is preferably 160 to 270°C, more preferably 180 to 250°C, particularly preferably 200 to 230°C. If the melting point of the PA resin is too low, the heat resistance tends to decrease. On the other hand, if the melting point of the PA resin is too high, the difference in melting point with resins used in other layers may become large, which may be unfavorable from the viewpoint of moldability. From the above viewpoint, preferred PA resins include, for example, nylon 6 (melting point: about 220°C), nylon 6 / 66 (melting point: about 200°C), and the like. [Polyolefin resin layer (B)] The polyolefin resin layer (B) constituting the multilayer structure of the present invention contains a polyolefin resin (b1) and a compatibilizer (b2). Since the multilayer structure of the present invention has a polyolefin resin layer (B) containing a polyolefin resin (b1) and a compatibilizer (b2), it is possible to improve the compatibility of the entire multilayer structure after recycling. , the multilayer structure can be easily recycled. The total content of the polyolefin resin (b1) and compatibilizer (b2) in the polyolefin resin layer (B) is 1% by mass or more, 2% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass. As mentioned above, it is more preferable that the total content of the polyolefin resin (b1) and the compatibilizer (b2) in the polyolefin resin layer (B) is 50 mass% or more, although it is not particularly limited, such as 40 mass% or more, More preferably, the content is 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, and 100% by mass. Note that the polyolefin resin layer (B) preferably does not contain EVOH, and even if EVOH is contained, the content of EVOH in the polyolefin resin layer (B) is preferably 5% by mass or less. The content of the polyolefin resin (b1) in the polyolefin resin layer (B) is not particularly limited, but is preferably 1 to 99% by mass, more preferably 30 to 95% by mass, particularly preferably 50 to 90% by mass. . From the viewpoint of recyclability, it is preferable that the amount is within the above range. The content of the compatibilizer (b2) in the polyolefin resin layer (B) is not particularly limited, but is preferably 1 to 99% by mass, more preferably 5 to 50% by mass, particularly preferably 10 to 30% by mass. . From the viewpoint of moldability, it is preferable that the amount is within the above range. The polyolefin resin layer (B) contains known plasticizers, lubricants, heat stabilizers, light stabilizers, and ultraviolet absorbers within a range that does not impede the effects of the present invention (for example, less than 30% by mass, preferably less than 5% by mass). Even if additives such as anti-oxidants, crystal nucleating agents, colorants, antistatic agents, surfactants, antibacterial agents, desiccants, oxygen absorbers, anti-blocking agents, and inorganic fillers are included as optional ingredients, Often, other polyolefin resins and compatibilizers may be blended. (Polyolefin resin (b1)) The polyolefin resin (b1) used in the polyolefin resin layer (B) is not particularly limited, but includes, for example, linear low density polyethylene (LLDPE), low density polyethylene (LDPE), very low density polyethylene (VLDPE), medium Polyethylene such as density polyethylene (MDPE) and high density polyethylene (HDPE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), ionomer, ethylene-propylene (block or random) copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, Examples include ethylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymers, single or copolymers of olefins such as polybutene, polypentene, and polymethylpentene, and blends thereof. These may be used alone or in combination of two or more, and among them, polyethylene, ethylene-vinyl acetate copolymer (EVA), ethylene-propylene (block or random) copolymer, polypropylene (PP), and blends thereof. are preferable in terms of economy and mechanical properties, and polyethylene, polypropylene (PP) and ethylene-propylene (block or random) copolymers are particularly preferable since the effects of the present invention are particularly excellent. The melt flow rate (MFR) (190° C., load 2160 g) of the polyolefin resin (b1) is usually 0.1 to 50 g / 10 minutes, more preferably about 0.5 to 30 g / 10 minutes. (Compatibilizer (b2)) The compatibilizer (b2) used in the polyolefin resin layer (B) is characterized by a melt flow rate (MFR) of 600 g / 10 minutes (190° C., load 2160 g) or less. When the MFR of the compatibilizer (b2) is 600 g / 10 minutes or less, a multilayer structure with excellent transparency and impact resistance can be obtained. When the MFR of the compatibilizer (b2) exceeds 600 g / 10 minutes, transparency and impact resistance tend to be poor. The MFR of the compatibilizer (b2) is preferably 0.1 to 300 g / 10 minutes, more preferably 1 to 100 g / 10 minutes, particularly preferably 10 to 30 g / 10 minutes. From the viewpoint of compatibility with the polyolefin resin (b1), it is preferably within the above range. MFR is an index of the degree of polymerization of the compatibilizer (b2), and can be adjusted by adjusting the amount of polymerization initiator, the amount of solvent, the amount of modification, etc. The compatibilizer (b2) may have an MFR within the above range and be compatible with the polar group-containing resin (a) and the polyolefin resin (b1), and the type of resin is not particularly limited, but for example, , chemically adding an unsaturated carboxylic acid or its anhydride to an ethylene-vinyl acetate copolymer or its saponified product, a polyolefin resin, or an ethylene-vinyl acetate copolymer or a polyolefin resin by an addition reaction or a graft reaction. Examples include modified polyolefin polymers containing carboxyl groups obtained by bonding. Examples of the modified polyolefin polymers containing carboxyl groups include maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, maleic anhydride-modified ethylene-propylene (block and random) copolymers, and maleic anhydride-modified ethylene-propylene copolymers. Butene (block and random) copolymers, maleic anhydride-modified ethylene-ethyl acrylate copolymers, maleic anhydride-modified ethylene-vinyl acetate copolymers, maleic anhydride-modified polycyclic olefin resins, maleic anhydride-modified polyolefins Examples include maleic anhydride-modified polymers such as resins. These may be used alone or as a mixture of two or more. In addition, when two or more types of compatibilizers (b2) having different MFRs are used, the weighted average value of these compatibilizers (b2) is taken as the MFR of the compatibilizers (b2). The content of the compatibilizer (b2) with respect to the polar group-containing resin (a) in the multilayer structure of the present invention is 10 to 200 parts by mass, preferably 30 to 150 parts by mass, based on 100 parts by mass of the polar group-containing resin (a). Parts by weight, more preferably 50 to 100 parts by weight. The content is preferably within the above range from the viewpoint of further increasing the compatibility between the polar group-containing resin (a) and the polyolefin resin. If the content of the compatibilizer (b2) is less than 10 parts by mass based on 100 parts by mass of the polar group-containing resin (a), there is a tendency that no improvement in recyclability can be obtained. When the content of the compatibilizer (b2) exceeds 200 parts by mass based on 100 parts by mass of the polar group-containing resin (a), transparency and impact resistance tend to be poor. The MFR ratio (b1 / b2) of the polyolefin resin (b1) and the compatibilizer (b2) is not particularly limited, but is preferably 0.003 to 300, more preferably 0.03 to 60, and 0.1 to 30. is particularly preferred. When the MFR ratio is within the above range, the effects of the present invention can be further enhanced. By blending hydrotalcites with the compatibilizer (b2), the thermal stability of the polyolefin resin (B) can be further improved, and gel formation of the polyolefin resin (B) can be further suppressed. Can be done. Examples of hydrotalcites include hydrotalcite-based solid solutions represented by the following general formula (1). [Chemical 1] [(M 1 2+ ) y1 (M 2 2+ ) y2 ] 1-x M x 3+ (OH) 2 A n- x / n ・mH 2 O...(1) [M in the formula 1 2+ is at least one metal selected from Mg, Ca, Sr and Ba; 2 2+ is at least one metal selected from Zn, Cd, Pb, Sn, M x 3+ is a trivalent metal, A n- is an n-valent anion, and x, y1, y2, and m are positive numbers represented by 0<x≦0.5, 0.5<y1<1, y1+y2=1, and 0≦m<2, respectively. ] In the above general formula (1), M 1 2+ As Mg, Ca are preferable, and M 2 2+ As such, Zn and Cd are preferable. Further M x 3+ Examples of the material include Al, Bi, In, Sb, B, Ga, and Ti, which may be used alone or in combination of two or more, and among them, Al is practical. In addition, in the above general formula (1), A n- For example, CO 3 2- ,OH - ,HCO 3 - , salicylate ion, citrate ion, tartrate ion, NO 3 - ,I - , (OOC-COO) 2- ,ClO 4- ,CH 3 COO - ,C.O. 3 2- , (OOCHC=CHCOO) 2- , [Fe(CN) 6] 4- These can be used alone or in combination of two or more, but among them, CO 3 2- Ya OH - is useful. As a specific example of the hydrotalcite solid solution, [Mg 0.75 Zn 0.25 ] 0.67 Al 0.33 (OH) 2 (C.O. 3 ) 0.165 ・0.45H 2 O, [Mg 0.79 Zn 0.21 ] 0.7 Al 0.3 (OH) 2 (C.O. 3 ) 0.15 , [Mg 1 / 7 Ca 3 / 7 Zn 3 / 7 ] 0.7 Al 0.3 (OH) 2 (OOCHC=CHCOO) 0.15 ・0.41H 2 O, [Mg 6 / 7 Cd 1 / 7 ] 0.7 Al 0.3 (OH) 2 (CH 3 COO) 0.3 ・0.34H 2 O, [Mg 5 / 7 Pd 2 / 7 ] 0.7 Al 0.30 (OH) 2 (C.O. 3 ) 0.15 ・0.52H 2 O, [Mg 0.74 Zn 0.26 ] 0.68 Al 0.32 (OH) 2 (C.O. 3 ) 0.16 , [Mg 0.56 Zn 0.44 ] 0.68 Al 0.32 (OH) 2 (C.O. 3 ) 0.16 ・0.2H 2 O, [Mg 0.81 Zn 0.19 ] 0.74 Al 0.26 (OH) 2 (C.O. 3 ) 0.13 , [Mg 0.75 Zn 0.25 ] 0.8 Al 0.20 (OH) 2 (C.O. 3 ) 0.10 ・0.16H 2 O, [Mg 0.71 Zn 0.29 ] 0.7 Al 0.30 (OH) 2 (NO 3 ) 0.30 , [Mg 0.71 Zn 0.29 ] 0.7 Al 0.30 (OH) 2 (OOCHC=CHCOO) 0.15 , [Mg 0.14 Ca 0.57 Zn 0.28 ] 0.7 Al 0.30 (OH) 2.3 ・0.25H 2 Among them, [Mg 0.75 Zn 0.25 ] 0.67 Al 0.33 (OH) 2 (C.O. 3 ) 0.165 ・0.45H 2 O, [Mg 0.79 Zn 0.21 ] 0.7 Al 0.3 (OH) 2 (C.O. 3 ) 0.15 , [Mg 6 / 7 Cd 1 / 7 ] 0.7 Al 0.3 (OH) 2 (CH 3 COO) 0.3 ・0.34H 2 O, [Mg 5 / 7 Pd 2 / 7 ] 0.7 Al 0.30 (OH) 2 (C.O. 3 ) 0.15 ・0.52H 2 Examples include O. Other examples include, for example, a compound represented by the following general formula (2). [Case 2] M x Al y (OH) 2x+3y-2z (E) z ・aH 2 O...(2) [Wherein, M is Mg, Ca or Zn, E is CO 3 or HPO 4 , x, y, z are positive numbers, and a is 0 or a positive number. ] Specifically, as the compound represented by the above general formula (2), Mg 4.5 Al 2 (OH) 13 C.O. 3 ・3.5H 2 O, Mg 5 Al 2 (OH) 14 C.O. 3 ・4H 2 O, Mg 6 Al 2 (OH) 16 C.O. 3 ・4H 2 O, Mg 8 Al 2 (OH) 20 C.O. 3 ・5H 2 O, Mg 10 Al 2 (OH) 22 (C.O. 3 ) 2 ・4H 2 O, Mg 6 Al 2 (OH) 16 HPO 4 ・4H 2 O, Ca 6 Al 2 (OH) 16 C.O. 3 ・4H 2 O, Zn 6 Al 6 (OH) 16 C.O. 3 ・4H 2 Examples include O. In addition, it is not limited to the above, for example, Mg 2 Al(OH) 9 ・3H 2 Some of the OH in O is CO 3 or HPO 4 The same effect can be expected even when the chemical formula is not clearly shown, such as when the chemical formula is substituted with , or even when the water of crystallization is removed (a=0). In particular, among these, M is Mg and E is CO 3 Compounds are preferably used in terms of further improving the effects obtained by hydrotalcites. Regarding the particle size of hydrotalcites, for example, the average particle size is usually 10 μm or less, more preferably 5 μm or less, particularly preferably 1 μm or less. Note that the average particle diameter referred to here is a value measured by the LUZEX method. Note that among the above-mentioned hydrotalcites, it is particularly preferable to use the hydrotalcite-based solid solution represented by the above-mentioned general formula (1) from the viewpoint of obtaining better effects. By blending a higher fatty acid metal salt into the compatibilizer (b2), the thermal stability of the polyolefin resin (B) can be further improved, and gel formation of the polyolefin resin (B) can be further suppressed. Can be done. Examples of higher fatty acid metal salts include alkali metal salts such as lithium, sodium, and potassium of organic acids having 8 or more carbon atoms (more preferably 12 to 30 carbon atoms, particularly preferably 12 to 20 carbon atoms), magnesium, Examples include metal salts such as alkaline earth metal salts such as calcium and barium, and transition metal salts such as zinc, copper, cobalt, iron, and manganese. Among them, metal salts with carbon numbers of 12 to 20 alkaline earth metal and transition metal salts are preferred, particularly the magnesium, calcium and zinc salts of stearic acid, hydroxystearic acid, oleic acid and lauric acid. By blending an antioxidant into the compatibilizer (b2), the thermal stability of the polyolefin resin (B) can be further improved, and gel formation of the polyolefin resin (B) can be further suppressed. can. Examples of antioxidants include hindered phenol compounds: dibutylhydroxytoluene, 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 4,4'-thiobis- (6-t-butylphenol), 2,2'-methylene-bis(4-methyl-6-t-butylphenol), Tetrakis-[methylene-3-(3',5'-di-t-butyl-4') -hydroxyphenyl)propionate]methane, N,N'-hexamethylene-bis(3,5-di-t-butyl-4'-hydroxy-hydrocinnamamide), 1,3,5-trimethyl-2,4 , 6 tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, pentaerythritol-tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], triethylene glycol -bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate], 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl) ) propionate], 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-triazine, 2,2-thio-diethylenebis [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 3,5-di- t-Butyl-4-hydroxy-benzylphosphonate-diethyl ester, bis(ethyl 3,5-di-t-butyl-4-hydroxybenzylphosphonate) calcium, tris-(3,5-di-t-butyl) -4-hydroxybenzyl)-isocyanurate, 2,4-bis[(octylthio)methyl]-o-cresol, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, n -Octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4- Methylphenyl acrylate, 2-[1-(2-hydroxy-3,5-di-t-pentylphenyl)ethyl]-4,6-di-t-pentylphenyl acrylate, 4,4'-butylidene bis(3-methyl -6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), 3,9-bis{2-[3-(3-t-butyl-4-hydroxy-5- methylphenyl)-propionyloxy]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro(5.5)undecane, etc.; Phosphite compounds: triphenylphosphite, tris(p- Triarylphosphites such as nonylphenyl) phosphite and tris(2,4-di-t-butylphenyl) phosphite, monoalkyl diphenyl phosphites such as diphenyl isooctyl phosphite and diphenyl isodecyl phosphite, and phenyl diphenyl phosphites. alkylaryl phosphites such as dialkylmonophenyl phosphites such as isooctyl phosphite and phenyldiisodecyl phosphite; trialkyl phosphites such as triisooctyl phosphite and tristearylphosphite; bis(2,4-di-t- butylphenyl) pentaerythritol-di-phosphite, etc.; thioether compounds: pentaerythritol-tetrakis-(β-laurylthiopropionate), tetrakis[methylene-3-(dodecylthio)propionate]methane, bis[2-methyl- 4-(3-n-alkylthiopropionyloxy)-5-t-butylphenyl] sulfide, dilauryl-3,3'-thiodipropionate, dimistyryl-3,3'-thiodipropionate, distearyl-3, 3'-thiodipropionate, pentaerythryl-tetrakis (3-laurylthiopropionate), ditridecyl-3,3'-thiodipropionate, 2-mercaptobenzimidazole, etc.; hindered amine compounds: dimethyl succinate; 1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpepyridine polycondensate, poly{[6-(1,1,3,3-tetramethylbutyl)amino-1 ,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl) ) imino]}, N,N'-bis(3-aminopropyl)ethylenediamine / 2,4-bis[N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino] -6-chloro-1,3,5-triazine condensate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4- piperidinyl) sebacate, 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonate bis(1,2,2,6,6-pentamethyl-4-piperidyl), etc.; Benzotriazole compounds: 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl)benzotriazole, 2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3,5 -di-t-butyl-2-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3,5-di-t-amyl-2-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-5' -t-octylphenyl)benzotriazole, methyl-3-[3-t-butyl-5-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]propionate-polyethylene glycol condensate, hydroxyphenylbenzotriazole derivative , 2-[2-hydroxy-3-(3,4,5,6-tetra-hydrophthalimido-methyl)-5-methylphenyl]benzotriazole, etc.; benzophenone compounds: 2-hydroxy-4-methoxybenzophenone, 2- Examples include hydroxy-4-octyloxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, etc., and at least one kind can be selected from these. The antioxidant may be in any desired form, such as powder, granules, liquid, paste, or emulsion. Among these, hindered phenolic antioxidants are preferred, particularly pentaerythritol-tetrakis-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate and octadecyl-3-(3,5-di -t-butyl-4-hydroxyphenyl)propionate is preferably used from the viewpoint of obtaining better effects. [Adhesive resin layer (C)] The multilayer structure of the present invention may further include an adhesive resin layer (C) if necessary. The adhesive resin layer (C) may be provided as a layer for bonding the polar group-containing resin layer (A) and the polyolefin resin layer (B). As the adhesive resin contained in the adhesive resin layer (C), for example, a carboxyl group obtained by chemically bonding an unsaturated carboxylic acid or its anhydride to a polyolefin resin by an addition reaction, a graft reaction, etc. Examples include modified polyolefin polymers. Examples of the modified polyolefin polymers containing carboxyl groups include maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, maleic anhydride-modified ethylene-propylene (block and random) copolymers, and maleic anhydride-modified ethylene-propylene copolymers. Examples include maleic anhydride-modified polymers such as ethyl acrylate copolymer, maleic anhydride-modified ethylene-vinyl acetate copolymer, maleic anhydride-modified polycyclic olefin resin, and maleic anhydride-modified polyolefin resin. These may be used alone or as a mixture of two or more. As adhesive resins, maleic anhydride-modified polyethylene and maleic anhydride are particularly useful because they contribute not only to the adhesiveness of the resin but also to suppressing gel formation during melting and heating and suppressing decreases in transparency. Maleic anhydride-modified polymers such as modified ethylene-α-olefin copolymers are preferred. The acid value of the maleic anhydride-modified polymer is usually 50 mgKOH / g or less, preferably 30 mgKOH / g or less, particularly preferably 20 mgKOH / g or less. If the acid value is too high, the number of reaction points with the hydroxyl groups in EVOH will increase, and a highly polymerized compound will be generated during the melt-kneading process, resulting in a decrease in stability during extrusion processing, making it difficult to obtain a good molded product. There is. Note that the lower limit of the acid value is usually 1 mgKOH / g, preferably 2 mgKOH / g. Moreover, the above acid value is measured based on JISK0070. When using maleic anhydride-modified polyethylene as the maleic anhydride-modified polymer, the MFR (190°C, load 2160 g) is usually 0.01 to 150 g / 10 minutes, preferably 0.1 to 50 g / 10 minutes. It is more preferably 1 to 25 g / 10 minutes, and still more preferably 3 to 10 g / 10 minutes. Further, when a maleic anhydride modified ethylene-α-olefin copolymer is used as the maleic anhydride modified polymer, the MFR (230°C, load 2160 g) is usually 0.1 to 150 g / 10 minutes, preferably It is 0.5 to 100 g / 10 minutes, more preferably 1 to 50 g / 10 minutes, and even more preferably 5 to 35 g / 10 minutes. If the MFR is too large or too small, there is a tendency for molding defects to occur when molding a multilayer structure, which is not preferable. Incidentally, arbitrary additives can be appropriately blended into the adhesive resin layer (C) within a range (for example, less than 30% by mass) that does not impair the effects of the present invention. Examples of such additives include heat stabilizers, ultraviolet absorbers, light stabilizers, antioxidants, antistatic agents, neutralizing agents, rust preventives, and pigments. [Multilayer structure] Next, the multilayer structure of the present invention will be explained. The multilayer structure of the present invention includes a polar group-containing resin layer (A), a polyolefin resin (b1), and a compatibilizer (b2) having a melt flow rate of 600 g / 10 minutes or less (190°C, load 2160 g). It is a multilayer structure having a polyolefin resin layer (B). The multilayer structure of the present invention only needs to contain the polar group-containing resin layer (A) and the polyolefin resin layer (B), and the layer structure other than these is not particularly limited. The multilayer structure of the present invention may include an adhesive resin layer (C) as required. For example, a polyolefin-based resin layer (C) may be added to the polar group-containing resin layer (A) via the adhesive resin layer (C) A structure (A / C / B) in which resin layers (B) are laminated, or a polyolefin resin layer (B) on both sides of the polar group-containing resin layer (A) via an adhesive resin layer (B). A laminated structure (B / C / A / C / B) can be mentioned. Another layer (D) may be laminated between these layers or on the surface layer. As a method for laminating the multilayer structure, a known method can be used. For example, a method of melt-extrusion laminating an adhesive resin layer (C) and a polyolefin resin layer (B) on a film or sheet that will become the polar group-containing resin layer (A), or conversely, a method of laminating an adhesive resin layer (C) and a polyolefin resin layer (B) on a film or sheet, etc. A method of melt-extrusion laminating a resin composition that will become a polar group-containing resin layer (A) on a polyolefin resin layer (B), or a method of coextruding three layers of (A), (B), and (C). There are several methods. Alternatively, a method of applying a solution of a resin composition to become a polar group-containing resin layer (A) on a polyolefin resin layer (B) provided with an adhesive resin layer (C), and then removing the solvent, etc. can be mentioned. Among these, coextrusion is preferred in view of cost and environment. [Other layers (D)] In the multilayer structure of the present invention, at least one other layer (D) may be laminated between the layers (A) to (B) or the layers (A) to (C) or on the surface layer. Other layers (D) include a base material layer (D1) for adding strength etc. to the multilayer structure, and an adhesive for joining this base material layer (D1) and layers (A) to (C). agent layer (D2), etc. (Base material layer (D1)) As the material used for the base layer (D1), various thermoplastic resins (hereinafter referred to as "base resin") are used. Furthermore, recycled resin obtained by remelting and molding end portions, defective products, etc. generated during the process of manufacturing the multilayer structure of the present invention may also be used. Such recycled resin may include a molten mixture of a polar group-containing resin layer (A), a polyolefin resin layer (B), an adhesive resin layer (C), and other layers (D). The base resin used for the base layer (D1) includes linear low density polyethylene, low density polyethylene, very low density polyethylene, medium density polyethylene, high density polyethylene, and ethylene-propylene (block and random) copolymers. , polyethylene resins such as ethylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, polypropylene, polypropylene such as propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer A broad term that includes (unmodified) polyolefin resins such as polyolefin resins, polybutene, polypentene, and modified polyolefin resins such as unsaturated carboxylic acid-modified polyolefin resins obtained by graft-modifying these polyolefins with unsaturated carboxylic acids or their esters. Polyolefin resins, cyclic olefin resins, ionomers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-acrylic acid ester copolymers, polyester resins, polyamide resins (including copolymerized polyamides) , polyvinyl chloride, polyvinylidene chloride, acrylic resins, polystyrene, vinyl ester resins, polyester elastomers, polyurethane elastomers, halogenated polyolefins such as chlorinated polyethylene and chlorinated polypropylene, aromatic or aliphatic polyketones, etc. . (Adhesive layer (D2)) The adhesive used in the adhesive layer (D2) for bonding the base layer (D1) and the layers (A) to (B) or the layers (A) to (C) includes organic titanium compounds, isocyanates, etc. Known adhesives such as compounds, polyester compounds, and polyurethane compounds can be used, and may be appropriately selected depending on the type of thermoplastic resin constituting the base layer (D1). In addition to the adhesive layer (D2), the adhesive resin layer (C ) may be used. In addition, the thermoplastic resin used for the base material layer (D1) and the adhesive used for the adhesive layer (D2) may contain a content within a range that does not impede the spirit of the present invention (for example, 30% by mass or less, preferably 10% by mass or less). % or less), conventionally known plasticizers, fillers, clays (montmorillonite, etc.), colorants, antioxidants, antistatic agents, lubricants, core materials, antiblocking agents, ultraviolet absorbers, waxes, etc. Can be blended. When the multilayer structure of the present invention includes at least one other layer (D) such as a base material layer (D1) and an adhesive layer (D2), the following manufacturing method may be used, for example. can be mentioned. (i) A method of laminating all the layers by co-extruding the resin that will form layers (A) to (B) or layers (A) to (C) and the resin that will form another layer (D): ( ii) A method of dry laminating a separately formed film, sheet, etc. that becomes the other layer (D) with the layers (A) to (B) or the layers (A) to (C); (iii) Separately. Melt and coextrude the resin that will become the layers (A) to (B) or the layers (A) to (C) on the surface of the formed film, sheet, etc. that will become the other layer (D), or a laminate that is an appropriate combination of these. (iv) A solution of the resin that will become the other layer (D) is applied to the (A) to (B) layers or (A) to (C) layers, and then the solvent is removed. Method. Among them, from the viewpoint of productivity, the method (i) of co-extruding the resin that will become the layers (A) to (B) or the layers (A) to (C) and the resin that will become the other layer (D) is preferred. Alternatively, without using another layer (D), for example, a polyolefin resin layer (B) is laminated on both sides of a polar group-containing resin layer (A) via an adhesive resin layer (C). When obtaining a layered structure, as already mentioned, it is preferable to coextrude these layers all at once. In the case of coextrusion molding, the extrusion molding temperature (barrel temperature of the extruder) of the resin composition is normally set appropriately in the range of 150 to 300°C, preferably 160 to 250°C. In the present invention, the extruder barrel temperature means the surface temperature of the extruder barrel. If the extruder barrel has multiple sections and the individual sections are set at different temperatures, the highest temperature of these is the barrel temperature. The obtained multilayer structure may be subjected to (heating) stretching treatment if necessary. The stretching treatment may be either uniaxial stretching or biaxial stretching, and in the case of biaxial stretching, simultaneous stretching or sequential stretching may be performed. Further, as the stretching method, a method with a high stretching ratio among roll stretching methods, tenter stretching methods, tubular stretching methods, stretch blowing methods, vacuum-pressure forming, etc. can be adopted. The stretching temperature is the temperature near the multilayer structure, and is usually selected from a range of about 40 to 170°C, preferably about 60 to 160°C. If the stretching temperature is too low, the stretching properties tend to be poor, and if the stretching temperature is too high, it tends to be difficult to maintain a stable stretched state. Note that heat setting may be further performed for the purpose of imparting dimensional stability after stretching. Heat setting can be carried out by well-known means, for example, the multilayer structure (in the form of a stretched film) is usually heated at 80 to 180°C, preferably 100 to 165°C, for about 2 to 600 seconds while maintaining a tensioned state. Perform heat treatment. The thickness of the multilayer structure (including stretched ones) and the thickness of the polar group-containing resin layer (A) and the polyolefin resin layer (B) that constitute the multilayer structure depend on the layer structure and the resin content of each layer. The thickness of the entire multilayer structure is usually 10 to 5,000 μm, preferably 30 to 3,000 μm, and particularly preferably 50 to 2,000 μm, although this cannot be said unconditionally depending on the type, use, packaging form, required physical properties, etc. The thickness of the polar group-containing resin layer (A) is usually 1 to 500 μm, preferably 3 to 300 μm, particularly preferably 5 to 200 μm. The thickness of the polyolefin resin layer (B) is usually 1 to 300 μm, preferably 5 to 200 μm, particularly preferably 10 to 100 μm. The thickness of the adhesive resin layer (C) is usually 0.5 to 250 μm, preferably 1 to 150 μm, particularly preferably 3 to 100 μm. The thickness of the base layer (D1) is usually 1 to 500 μm, preferably 3 to 300 μm, particularly preferably 5 to 200 μm. The thickness of the adhesive layer (D2) is usually 0.5 to 250 μm, preferably 1 to 150 μm, particularly preferably 3 to 100 μm. Further, the ratio A / B between the thickness of the polar group-containing resin layer (A) and the thickness of the polyolefin resin layer (B) (both thicknesses of a single layer) is usually 1 / 50 to 10 / 1, preferably 1 / 30. ~5 / 1, particularly preferably 1 / 10 ~ 3 / 1. When A / B is within the above range, the effects of the present invention can be obtained more effectively. The image clarity of the multilayer structure of the present invention is preferably 70.5% or more, more preferably 75% or more, particularly preferably 80% or more, and most preferably 100%. The image sharpness of the multilayer structure can be measured, for example, by the method described in Examples below. The impact strength of the multilayer structure of the present invention is preferably 170 g or more, more preferably 200 g or more, even more preferably 230 g or more, particularly preferably 250 g or more, particularly preferably 260 g or more. The impact strength of the multilayer structure can be measured, for example, by the method described in Examples below. The multilayer structure of the present invention contains a specific compatibilizer (b2) in a specific proportion, so it is a multilayer structure that is easy to recycle and has excellent transparency and impact resistance. [Applications of multilayer structure] In addition to general foods, the multilayer structure of the present invention can be used for various packaging materials, containers, and packaging for seasonings such as mayonnaise and dressings, fermented foods such as miso, oil and fat foods such as salad oil, beverages, cosmetics, and pharmaceuticals. It can be suitably used as a gas barrier layer of packaging materials such as films. Additionally, the multilayer structure of the present invention is suitable for recycling. [Resin composition] The multilayer structure of the present invention has excellent recyclability without adding a separate compatibilizing agent when recycling offcuts and molded products of the multilayer structure. For recycling, a resin composition or the like obtained by crushing and repelletizing the offcuts or molded products of the multilayer structure of the present invention is used. The resin composition includes a polar group-containing resin (a) containing an ethylene-vinyl alcohol copolymer and / or polyamide, a polyolefin resin (b1), a compatibilizer (b2), and an adhesive resin (c), The melt flow rate of the compatibilizer (b2) is 600 g / 10 minutes (190°C, load 2160 g) or less, and the content of the compatibilizer (b2) is based on 100 parts by mass of the polar group-containing resin (a). The amount is 10 to 200 parts by mass. Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof. In addition, in the examples, "part" means a mass standard. Prior to the example, the following components were prepared. - Polar group-containing resin (a): EVOH (ethylene structural unit content 32 mol%, MFR 3.5 g / 10 min (210°C, load 2160 g), saponification degree 99.6 mol%) ・Polyolefin resin (b1-1): Linear low density polyethylene (LLDPE) (“UF230” manufactured by Japan Polyethylene Co., Ltd., MFR: 1.0 g / 10 minutes (190°C, load 2160 g)) ・Polyolefin resin (b1-2): Linear low-density polyethylene (LLDPE) (“UF641” manufactured by Japan Polyethylene Co., Ltd., MFR: 2.1 g / 10 minutes (190°C, load 2160 g)) ・Compatibilizer (b2-1): Maleic anhydride modified ethylene-butene copolymer (MFR: 24 g / 10 minutes (190°C, load 2160 g), density: 0.87 g / cm 3 ) - Compatibilizer (b2-2): 88 parts of ethylene-vinyl acetate copolymer (vinyl acetate content: 28%, MFR: 5.7 g / 10 minutes (190°C, load 2160 g)), 2 parts of ethylene -Saponified vinyl acetate copolymer (content of ethylene structural unit: 89 mol%, degree of saponification: 99 mol%, MFR: 6.5 g / 10 minutes (190°C, load 2160 g)), 5 parts of hydrotal A mixture of site solid solution, 5 parts calcium stearate, 0.5 parts pentaerythritol-tetrakis [3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate] (MFR: 6 g / 10 min (190 °C, load 2160g), density: 1.0g / cm 3 ) ・Compatibilizer (b2-3): Maleic anhydride modified ethylene-octene copolymer (“Retain (trademark) 3000” manufactured by Dow Chemical Company, MFR: 660 g / 10 minutes (190 ° C., load 2160 g), density: 0 .87g / cm 3 ) ・Adhesive resin (c1): Modified polyolefin resin (“MODIC (trademark) M512” manufactured by Mitsubishi Chemical Corporation) (MFR: 1.0 g / 10 minutes (190°C, load 2160 g), density: 0.900 g / cm 3 ) ・Adhesive resin (c2): Modified polyolefin resin (“MODIC (trademark) M533” manufactured by Mitsubishi Chemical Corporation) (MFR: 2.5 g / 10 minutes (190°C, load 2160 g), density: 0.920 g / cm 3 ) ・Base resin (d1): Linear low-density polyethylene (LLDPE) (“UF230” manufactured by Japan Polyethylene Co., Ltd., MFR: 1.0 g / 10 minutes (190 ° C., load 2160 g)) <Example 1> 63 parts of polyolefin resin (b1) and 37 parts of compatibilizer (b2-1) were mixed to prepare a resin composition for polyolefin resin layer (B). The amount of the compatibilizer (b2-1) is equivalent to the amount of EVOH contained in the multilayer structure (100 parts of the compatibilizer (b2-1) per 100 parts of EVOH). The resin composition prepared above, the polar group-containing resin (a), the adhesive resin (c), and the base resin (d1) were supplied to a 5-type, 7-layer, multilayer coextrusion cast film forming apparatus, and the following conditions were applied. By multilayer coextrusion molding, base material layer (D1) / polyolefin resin layer (B) / adhesive resin layer (C) / polar group-containing resin layer (A) / adhesive resin layer (C) / polyolefin resin A multilayer structure (film) having a structure of 4 types and 7 layers of layer (B) / base material layer (D1) was obtained. The thickness (μm) of each layer of the multilayer structure was 20 / 20 / 5 / 10 / 5 / 20 / 20. (Multilayer coextrusion molding conditions) ・Polar group-containing resin layer (A) Extruder: 40mmφ single screw extruder (barrel temperature: 220°C) ・Polyolefin resin layer (B) extruder: 40mmφ single screw extruder (barrel temperature: 210°C) ・Adhesive resin layer (C) extruder: 32mmφ single screw extruder (barrel temperature: 210°C) ・Base material layer (D1) extruder: 50mmφ single screw extruder (barrel temperature: 210°C) ・Die: 5 types 7 layer feed block type T die (Die temperature: 210℃) ・Take-up speed: 11m / min ・Roll temperature: 80℃ <Examples 2 to 8, Comparative Examples 1 to 3> A multilayer structure was produced in the same manner as in Example 1 except for the changes shown in Table 1, and various evaluations were performed according to the methods shown below. [Evaluation of image clarity] The image clarity (transparency) of the multilayer structures of Examples 1 to 8 and Comparative Examples 1 to 3 was measured by a transmission method in accordance with JIS K 7374 "Plastics - How to determine image clarity". The film test piece was measured with the film machine direction as the vertical direction. The measuring device used was an ICM-1 model image clarity measuring device manufactured by Suga Test Instruments. A 1.0 mm optical comb was used. [Evaluation of impact resistance] Examples 1 to 8 and Comparative Examples 1 to 8 were tested using aluminum darts with a diameter of 38 mm and a mass of 32 g according to Method A in accordance with JIS K 7124-1 "Plastic films and sheets - impact test method using free-fall dart method". The impact strength of the multilayer structure No. 3 was measured using No. 3 manufactured by Toyo Seiki Seisakusho in an atmosphere of 23° C. and 50% RH. Evaluation was made using a 613 Dart Impact Tester. [Evaluation of recyclability] The film of Example 1 was crushed, and using a twin screw extruder (manufactured by Japan Steel Works, TEX30α, D=25 mmφ, L / D=56), the temperature was set at 210°C, the screw rotation speed was 300 rpm, and the extrusion rate was 20 kg / h. A recycled composition was prepared by melt-kneading. The obtained recycled composition was molded into a film with a thickness of 0.1 mm using a single-layer T-die film molding machine (manufactured by GM Engineering, 40 mmφ, lip opening: 0.3 mm) at a set temperature of 220°C and a screw rotation speed of 60 rpm. A film was produced. The impact resistance of the produced film was measured by the same method as above. A film (reference example) that was the same as in Example 1 except that it did not contain a compatibilizer was produced, and its impact resistance was measured in the same manner. Examples 1 to 8 are comparative examples containing a compatibilizer having an MFR outside the range specified by the present invention by making the polyolefin resin layer (B) contain a specific amount of a compatibilizer having a specific MFR. 1 and 3 and Comparative Example 2 in which the content of the compatibilizer is outside the range specified by the present invention, the multilayer structure has excellent image clarity (transparency) and dart impact (impact resistance). I understand. Furthermore, from Table 2, it can be seen that by containing a specific amount of a compatibilizer having a specific MFR in the polyolefin resin layer (B), the recyclability is improved compared to the case where no compatibilizer is included. Recognize. When different resin layers are coextruded as in the above example, the fluidity of the molten resin in each resin layer is different, resulting in turbulence in the resin flow at the confluence of the resin layers (interface between the resin layers). Cheap. Since resins having different MFRs are mixed in the polyolefin resin layer containing a compatibilizing agent, as in Comparative Example 1, a polyolefin resin containing a compatibilizing agent whose MFR is significantly different from that of the polyolefin resin. When the layer is used as an intermediate layer of a multilayer structure, in addition to the resin turbulence that occurs at the resin layer interface, smaller turbulence also occurs at the confluence of the polyolefin resin layer and the adjacent layer, which causes the multilayer structure to It is thought that the transparency and mechanical strength (impact resistance) of the material decreased. Although the above embodiments have shown specific embodiments of the present invention, the above embodiments are merely illustrative and should not be construed as limiting. Various modifications apparent to those skilled in the art are intended to be within the scope of the invention. In addition to general foods, the multilayer structure of the present invention can be used for various packaging materials, containers, and packaging for seasonings such as mayonnaise and dressings, fermented foods such as miso, oil and fat foods such as salad oil, beverages, cosmetics, and pharmaceuticals. It can be suitably used as a gas barrier layer of packaging materials such as films. Additionally, the multilayer structure of the present invention is suitable for recycling.

Claims

1. a polar group-containing resin layer (A) containing a polar group-containing resin (a) containing an ethylene-vinyl alcohol copolymer and / or a polyamide; A polyolefin resin layer (B) containing a polyolefin resin (b1) and a compatibilizer (b2), and An adhesive resin layer (C) is provided, The melt flow rate of the compatibilizer (b2) is 600 g / 10 min (190° C., load 2160 g) or less, A multilayer structure, wherein the content of the compatibilizer (b2) is 10 to 200 parts by mass per 100 parts by mass of the polar group-containing resin (a).

2. 2. The multilayer structure according to claim 1, wherein the content of the compatibilizer (b2) is 1 to 99% by mass relative to the polyolefin resin layer (B).

3. 3. The multilayer structure according to claim 1, wherein the melt flow rate of the compatibilizer (b2) is 0.1 to 100 g / 10 min (190° C., load 2160 g).

4. 3. The multilayer structure according to claim 1, wherein the compatibilizer (b2) is a maleic anhydride-modified ethylene-butene copolymer.

5. 3. The multilayer structure according to claim 1, wherein the compatibilizer (b2) is an ethylene-vinyl acetate copolymer.

6. 3. The multilayer structure according to claim 1, wherein the ratio (b1 / b2) of the melt flow rates of the polyolefin resin (b1) and the compatibilizer (b2) is 0.003 to 300.

7. The multilayer structure according to claim 1 or 2, wherein the polyolefin-based resin layer (B) contains, as an optional component, less than 5% by mass of an inorganic filler.

8. 3. The multilayer structure according to claim 1, wherein the polyolefin resin (b1) is one or more polyethylenes selected from the group consisting of linear low-density polyethylene, low-density polyethylene, very low-density polyethylene, medium-density polyethylene, and high-density polyethylene.

9. The multilayer structure according to claim 1 or 2, further comprising a substrate layer (D1).

10. A resin composition comprising a polar group-containing resin (a) containing an ethylene-vinyl alcohol copolymer and / or a polyamide, a polyolefin resin (b1), a compatibilizer (b2), and an adhesive resin, wherein the compatibilizer (b2) has a melt flow rate of 600 g / 10 min (190°C, load 2160 g) or less, and the content of the compatibilizer (b2) is 10 to 200 parts by mass per 100 parts by mass of the polar group-containing resin (a).