Multilayer body, packaging material, and method for producing packaging material

Abstract

The present invention provides: a multilayer body which has a polyolefin resin layer that contains a xylylenediamine-based polyamide resin, and a barrier layer; and a packaging material, and a method for producing a packaging material. Disclosed is a multilayer body which has a polyolefin resin layer (A) that contains an acid-unmodified polyolefin resin as a main component, and a barrier layer (B) that contains a barrier resin as a main component. The polyolefin resin layer (A) contains 0.1-8% by mass of a xylylenediamine-based polyamide resin and 0.1-15% by mass of an acid-modified polyolefin resin. The xylylenediamine-based polyamide resin contains a diamine-derived constituent unit and a dicarboxylic acid-derived constituent unit, 70% by mole or more of the diamine-derived constituent unit is derived from xylylenediamine, and 70% by mole or more of the dicarboxylic acid-derived constituent unit is derived from an α, ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms.

Description

Multilayer body, packaging material, and method for manufacturing packaging material

[0001] The present invention relates to a multilayer body, a packaging material, and a method for manufacturing a packaging material, and more particularly to a multilayer body using a regrind material.

[0002] In recent years, the use of regrind materials has been considered to reduce the burden on the environment. Regrind materials are materials derived from scraps, test pieces, and rejected products that are generated during the plastic molding process. The use of such regrind materials has attracted considerable attention from the perspective of environmental considerations, such as reducing waste and making effective use of resources (Patent Document 1, Patent Document 2).

[0003] JP 2018-135133 A JP 2000-264325 A

[0004] The use of regrind material will be described in detail with reference to FIG. 1. FIG. 1 is an image diagram showing the relationship between plastic molding and regrind material, in which 1 denotes a raw material, 2 denotes a container molded from the raw material, 3 denotes the material obtained after the raw material is stamped, and 4 denotes the regrind material. In FIG. 1, the scales of the container 2 molded from the raw material and the material 3 obtained after the raw material is stamped are not the same. Typically, the container 2 corresponds to one of the openings of the stamped material 3. The stamped material 3 can be crushed and reused as regrind material 4. It is particularly desirable to be able to reuse this regrind material 4 as raw material 1. However, when raw material 1 is a multilayer body, it may be difficult to reuse the regrind material. FIG. 2 is a cross-sectional schematic diagram showing an example of a multilayer body, in which 1 denotes the raw material (multilayer body), 5 denotes a polyolefin resin layer, 6 denotes a barrier layer containing a barrier resin, and 7 denotes an adhesive layer containing an adhesive. When the regrind material generated from such raw material (multilayer body) 1 is blended into the polyolefin resin layer 5, the polyolefin resin layer 5 contains not only the polyolefin resin but also a barrier resin and an adhesive. In particular, when the barrier resin is a xylylenediamine-based polyamide resin, the impact resistance of the resulting multilayer body or packaging material is poor. Furthermore, the transparency of the multilayer body or packaging material is poor. That is, it is desired to provide a multilayer body having a polyolefin resin layer and a barrier layer that exhibits excellent impact resistance without reducing transparency, even when a xylylenediamine-based polyamide resin is blended into the polyolefin resin layer. The present invention aims to solve this problem and to provide a multilayer body having a polyolefin resin layer and a barrier layer that exhibits excellent impact resistance without reducing transparency, as well as a packaging material and a method for producing the packaging material.

[0005] In light of the above-mentioned problems, the present inventors have conducted studies and found that the above-mentioned problems can be solved by blending an acid-modified polyolefin resin with a polyolefin resin layer containing a xylylenediamine-based polyamide resin. Specifically, the above-mentioned problems have been solved by the following means. <1> A multilayer body having a polyolefin resin layer (A) containing an acid-unmodified polyolefin resin as a main component and a barrier layer (B) containing a barrier resin as a main component, wherein the polyolefin resin layer (A) contains 0.1 to 8 mass % of a xylylenediamine-based polyamide resin and 0.1 to 15 mass % of an acid-modified polyolefin resin, and the xylylenediamine-based polyamide resin contains diamine-derived structural units and dicarboxylic acid-derived structural units, wherein 70 mol % or more of the diamine-derived structural units are derived from xylylenediamine, and 70 mol % or more of the dicarboxylic acid-derived structural units are derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. <2> The multilayer body according to <1>, wherein the acid-unmodified polyolefin resin contained in the polyolefin resin layer (A) comprises an acid-unmodified polypropylene resin. <3> The multilayer body according to <1> or <2>, wherein the acid-modified polyolefin resin contained in the polyolefin resin layer (A) comprises a maleic anhydride-modified polypropylene resin. <4> The multilayer body according to any one of <1> to <3>, wherein the polyolefin resin layer (A) further comprises a polyamide resin having a refractive index difference of less than 0.08 from the acid-unmodified polyolefin resin. <5> The multilayer body according to <4>, wherein the polyamide resin having a refractive index difference of less than 0.08 from the acid-unmodified polyolefin resin comprises at least one selected from polyamide 6, polyamide 66, and polyamide 666. <6> The multilayer body according to any one of <1> to <5>, wherein the xylylenediamine-based polyamide resin contained in the polyolefin resin layer (A) is a regrind material.<7> The multilayer body according to any one of <1> to <6>, wherein the barrier resin contained in the barrier layer (B) is a xylylenediamine-based polyamide resin, and the xylylenediamine-based polyamide resin contains diamine-derived structural units and dicarboxylic acid-derived structural units, wherein 70 mol % or more of the diamine-derived structural units are derived from xylylenediamine, and 70 mol % or more of the dicarboxylic acid-derived structural units are derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. <8> The multilayer body according to any one of <1> to <7>, wherein the acid-unmodified polyolefin resin contained in the polyolefin resin layer (A) comprises a maleic anhydride-modified polypropylene resin, the polyolefin resin layer (A) further comprises a polyamide resin having a refractive index difference of less than 0.08 from that of the acid-unmodified polyolefin resin, and the polyamide resin having a refractive index difference of less than 0.08 from that of the acid-unmodified polyolefin resin comprises at least one selected from polyamide 6, polyamide 66, and polyamide 666, the xylylenediamine-based polyamide resin contained in the polyolefin resin layer (A) is a regrind material, and the barrier resin contained in the barrier layer (B) is a xylylenediamine-based polyamide resin, and the xylylenediamine-based polyamide resin comprises diamine-derived structural units and dicarboxylic acid-derived structural units, wherein 70 mol % or more of the diamine-derived structural units are derived from xylylenediamine and 70 mol % or more of the dicarboxylic acid-derived structural units are derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. <9> The multilayer body according to any one of <1> to <8>, further comprising a polyolefin resin layer (C) containing an acid-unmodified polyolefin resin as a main component, wherein the polyolefin resin layer (C), the polyolefin resin layer (A), and the barrier layer (B) are laminated in this order. <10> A packaging material comprising the multilayer body according to any one of <1> to <9>. <11> The packaging material according to <10>, which is for a container.<12> A method for producing the packaging material according to <10> or <11>, comprising melt-kneading a regrind material generated during the production of the packaging material according to <10> or <11> with a virgin, acid-unmodified polyolefin resin to produce a polyolefin resin layer (A) containing an acid-unmodified polyolefin resin as a main component. <13> A method for producing the packaging material according to <12>, comprising melt-kneading a virgin, acid-modified polyolefin resin in addition to the regrind material and the virgin, acid-unmodified polyolefin resin when producing the polyolefin resin layer (A).

[0006] The present invention makes it possible to provide a multilayer body having a polyolefin resin layer containing a xylylenediamine-based polyamide resin and a barrier layer, which has excellent impact resistance without reducing transparency, as well as a packaging material and a method for producing a packaging material.

[0007] Fig. 1 is an image diagram showing the relationship between plastic molding and grind material, Fig. 2 is a cross-sectional schematic diagram showing an example of a multilayer body, and Fig. 3 is a cross-sectional schematic diagram showing an example of a multilayer body of this embodiment.

[0008] Hereinafter, an embodiment of the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. Note that the following present embodiment is an example for explaining the present invention, and the present invention is not limited to this embodiment. Note that in this specification, the expression "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit. In this specification, various physical property values ​​and characteristic values ​​are those at 23°C unless otherwise specified.

[0009] In this specification, unless otherwise specified, the number average molecular weight is a value measured by the following method. The number average molecular weight (Mn) is measured using gel permeation chromatography (GPC) measurement, using a standard polymethyl methacrylate (PMMA) equivalent value. Two columns packed with a styrene polymer are used as the packing material, and hexafluoroisopropanol (HFIP) with a sodium trifluoroacetate concentration of 2 mmol / L is used as the solvent. The resin concentration is 0.02 mass%, the column temperature is 40 ° C, the flow rate is 0.3 mL / min, and the measurement is performed using a refractive index detector (RI). In addition, the calibration curve is measured by dissolving six levels of PMMA in HFIP.

[0010] In this specification, unless otherwise specified, the melting point (Tm) is a value measured by differential scanning calorimetry (DSC) in accordance with ISO 11357. Using a differential scanning calorimeter, the resin is placed in the measurement pan of the differential scanning calorimeter, heated to a temperature above the melting point at a heating rate of 10°C / min under a nitrogen atmosphere, and then rapidly cooled before measurement. The measurement conditions are a heating rate of 10°C / min, held at 280°C for 5 minutes, and then cooled to 100°C at a cooling rate of -5°C / min to determine the melting point (Tm). A "DSC-60" manufactured by Shimadzu Corporation is used as the differential scanning calorimeter. In this specification, the term "process" does not only refer to an independent process, but also includes processes that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved. If the measurement methods and other aspects described in the standards shown in this specification vary from year to year, they will be based on the standards as of January 1, 2023, unless otherwise stated. The scales and other aspects of Figures 1 to 3 may not be consistent with reality.

[0011] The multilayer body of the present embodiment is a multilayer body having a polyolefin resin layer (A) (hereinafter sometimes simply referred to as "polyolefin resin layer (A)") containing an acid-unmodified polyolefin resin as a main component, and a barrier layer (B) (hereinafter sometimes simply referred to as "barrier layer (B)") containing a barrier resin as a main component, wherein the polyolefin resin layer (A) contains 0.1 to 8 mass % of a xylylenediamine-based polyamide resin and 0.1 to 15 mass % of an acid-modified polyolefin resin, and the xylylenediamine-based polyamide resin contains diamine-derived structural units and dicarboxylic acid-derived structural units, wherein 70 mol % or more of the diamine-derived structural units are derived from xylylenediamine, and 70 mol % or more of the dicarboxylic acid-derived structural units are derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. This configuration makes it possible to provide a multilayer body having a polyolefin resin layer containing a xylylenediamine-based polyamide resin and a barrier layer, which has excellent impact resistance without sacrificing transparency. In some cases, such as when a regrind material is used in the polyolefin resin layer (A), the polyolefin resin layer (A) may contain a xylylenediamine-based polyamide resin. It has been found that in such cases, the transparency of the multilayer body may be impaired or the impact resistance may be poor. To solve these problems, in this embodiment, an acid-modified polyolefin resin is blended into the polyolefin resin layer (A) containing a xylylenediamine-based polyamide resin. The olefin portion of the acid-modified polyolefin resin enhances compatibility with the acid-unmodified polyolefin resin constituting the polyolefin resin layer (A). Furthermore, the acid group portion of the acid-modified polyolefin resin interacts with the amino group at the terminal of the xylylenediamine-based polyamide resin, enhancing compatibility with the xylylenediamine-based polyamide resin. As a result, it is presumed that the acid-unmodified polyolefin resin and the xylylenediamine-based polyamide resin are compatible with each other, making it possible to provide a multilayer body with excellent impact resistance without reducing transparency.

[0012] <Polyolefin Resin Layer (A)> The polyolefin resin layer (A) in this embodiment contains an acid-unmodified polyolefin resin as a main component, and further contains 0.1 to 8 mass % of a xylylenediamine-based polyamide resin and 0.1 to 15 mass % of an acid-modified polyolefin resin.

[0013] <<Acid-Unmodified Polyolefin Resin>> The acid-unmodified polyolefin resin refers to a polyolefin resin having a sufficiently smaller number of acid groups than the acid-modified polyolefin resin described below. Specifically, the amount of acid groups is 15 mol% or less of the acid groups contained in the acid-modified polyolefin resin, preferably 10 mol% or less, more preferably 5 mol% or less, even more preferably 3 mol% or less, still more preferably 1 mol% or less, and still more preferably contains no acid groups. The acid-unmodified polyolefin resin in this embodiment also preferably contains no polar groups other than acid groups.

[0014] The acid-unmodified polyolefin resin in this embodiment preferably contains a polypropylene resin (acid-unmodified polyolefin resin). The polypropylene resin in this embodiment includes a propylene homopolymer and a polyolefin copolymer copolymerized with less than 50% by mass (preferably 30% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and particularly preferably 3% by mass or less) of another olefin such as ethylene, and a propylene homopolymer is preferred. In the case of a polyolefin copolymer, it may be a block polymer or a random polymer.

[0015] The melting point of the acid-unmodified polyolefin resin is preferably 120°C or higher, more preferably 130°C or higher. By setting the melting point to be equal to or higher than the lower limit, moldability tends to be improved. Furthermore, the melting point of the acid-unmodified polyolefin resin is preferably 180°C or lower, more preferably 170°C or lower. By setting the melting point to be equal to or lower than the upper limit, moldability tends to be improved. When the polyolefin resin layer in this embodiment contains two or more acid-unmodified polyolefin resins, the melting point is the melting point of the acid-unmodified polyolefin resin with the largest content.

[0016] The acid-unmodified polyolefin resin used in this embodiment preferably has a melt flow rate of 1 g / 10 min or more, measured in accordance with JIS K7210-1:2014 under conditions of 230°C and 2.16 kgf. In this embodiment, by setting the MFR of the acid-unmodified polyolefin resin to the lower limit or higher, moldability can be improved. The MFR of the acid-unmodified polyolefin resin is preferably 0.5 g / 10 min or more, and is preferably 4.0 g / 10 min or less, more preferably 3.0 g / 10 min or less, even more preferably 2.0 g / 10 min or less, and even more preferably 1.8 g / 10 min or less. By setting the MFR within this range, moldability tends to be improved.

[0017] The refractive index of the acid-unmodified polyolefin resin is, for example, 1.40 or more, and may be, for example, less than 1.52, 1.51 or less, or 1.50 or less. The refractive index is measured in accordance with JIS K0062 1992. When the polyolefin resin layer (A) in this embodiment contains two or more types of acid-unmodified polyolefin resins, the refractive index of the acid-unmodified polyolefin resin is the refractive index of a mixture of the two or more types.

[0018] The polyolefin resin layer (A) in this embodiment contains an acid-unmodified polyolefin resin as a main component. The term "main component" refers to the component with the highest content among the components contained in the polyolefin resin layer (A) (the same applies hereinafter to "main component"). The content of the acid-unmodified polyolefin resin in the polyolefin resin layer (A) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, and even more preferably 75% by mass or more, relative to 100% by mass of the polyolefin resin layer (A). By setting the content at or above the lower limit, a decrease in transparency tends to be suppressed. Furthermore, the upper limit of the content of the acid-unmodified polyolefin resin in the polyolefin resin layer (A) is preferably an amount such that all components other than the xylylenediamine-based polyamide resin and the acid-modified polyolefin resin are polyolefin resin. The polyolefin resin layer (A) may contain only one type of acid-unmodified polyolefin resin, or two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0019] <<Xylylenediamine-Based Polyamide Resin>> The polyolefin resin layer (A) in the present embodiment comprises a xylylenediamine-based polyamide resin that includes diamine-derived structural units and dicarboxylic acid-derived structural units, in which 70 mol % or more of the diamine-derived structural units are derived from xylylenediamine, and 70 mol % or more of the dicarboxylic acid-derived structural units are derived from a linear α,ω-aliphatic dicarboxylic acid having 4 to 20 carbon atoms.

[0020] In the xylylenediamine-based polyamide resin, 70 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and even more preferably 99 mol% or more of the diamine-derived structural units are derived from xylylenediamine. The xylylenediamine is preferably meta-xylylenediamine or para-xylylenediamine, and more preferably meta-xylylenediamine. One preferred embodiment of the xylylenediamine-based polyamide resin in this embodiment is a xylylenediamine-based polyamide resin in which 70 mol% or more (preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and even more preferably 99 mol% or more) of the diamine-derived structural units are derived from meta-xylylenediamine.

[0021] Examples of diamines other than xylylenediamine include aromatic diamines such as paraphenylenediamine, and aliphatic diamines such as 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, octamethylenediamine, and nonamethylenediamine. These other diamines may be used alone or in combination of two or more. When a diamine other than xylylenediamine is used as the diamine component, it is used in an amount of 30 mol % or less, more preferably 1 to 25 mol %, and particularly preferably 5 to 20 mol %, of the diamine-derived structural units.

[0022] In this embodiment, as described above, 70 mol% or more of the dicarboxylic acid-derived structural units in the xylylenediamine-based polyamide resin are derived from a polyamide resin derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms. Of all the dicarboxylic acids constituting the dicarboxylic acid-derived structural units in the xylylenediamine-based polyamide resin, the lower limit of the proportion of α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms (preferably α,ω-linear aliphatic dicarboxylic acids having 4 to 8 carbon atoms, more preferably adipic acid) is 70 mol% or more, preferably 75 mol% or more, more preferably 80 mol% or more, even more preferably 85 mol% or more, even more preferably 90 mol% or more, 95 mol% or more, or even 99 mol% or more. The upper limit of the proportion of the α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms is 100 mol% or less.

[0023] As described above, the α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms is preferably an α,ω-linear aliphatic dicarboxylic acid having 4 to 8 carbon atoms. Examples of α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms that are suitable for use as a raw dicarboxylic acid component for polyamide resins include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, adipic acid, sebacic acid, undecanedioic acid, and dodecanedioic acid, and these can be used alone or in combination of two or more. Among these, adipic acid is preferred because it ensures that the melting point of the polyamide resin falls within a range suitable for molding and processing.

[0024] Examples of dicarboxylic acids other than α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms include phthalic acid compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid, and naphthalenedicarboxylic acids such as 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid, and these can be used alone or in combination. Preferably, the xylylenediamine-based polyamide resin is substantially free of structural units derived from terephthalic acid. By "substantially free," we mean 5 mol% or less, preferably 3 mol% or less, more preferably 1 mol% or less, and even more preferably 0 mol% of the molar amount of isophthalic acid contained in the xylylenediamine-based polyamide resin. By adopting such a configuration, appropriate moldability is maintained, and the gas barrier properties are less susceptible to change due to humidity.

[0025] The xylylenediamine-based polyamide resin used in this embodiment contains dicarboxylic acid-derived structural units and diamine-derived structural units as its main components, but may also contain structural units other than the dicarboxylic acid-derived structural units and diamine-derived structural units, as well as other moieties such as terminal groups. Examples of other structural units include, but are not limited to, lactams such as ε-caprolactam, valerolactam, laurolactam, and undecalactam, and structural units derived from aminocarboxylic acids such as 11-aminoundecanoic acid and 12-aminododecanoic acid. Furthermore, the xylylenediamine-based polyamide resin used in this embodiment contains trace components such as additives used in the synthesis. The xylylenediamine-based polyamide resin used in this embodiment typically contains 95% by mass or more, preferably 98% by mass or more, of dicarboxylic acid-derived structural units or diamine-derived structural units.

[0026] The melting point of the xylylenediamine-based polyamide resin is preferably 150°C or higher, more preferably 180°C or higher, even more preferably 200°C or higher, and even more preferably 220°C or higher, and is preferably 350°C or lower, more preferably 330°C or lower, even more preferably 310°C or lower, and even more preferably 290°C or lower.

[0027] The lower limit of the number average molecular weight (Mn) of the xylylenediamine-based polyamide resin is preferably 6,000 or more, more preferably 8,000 or more, and even more preferably 10,000 or more, and is preferably 35,000 or less, more preferably 30,000 or less, even more preferably 25,000 or less, and even more preferably 20,000 or less.

[0028] The refractive index of the xylylenediamine-based polyamide resin is, for example, 1.55 or more, or even 1.56 or more, and may be greater than 1.56, or may be, for example, less than 1.59, or 1.58 or less, and may be less than 1.58. The refractive index is measured in accordance with JIS K0062 1992. When the polyolefin resin layer (A) in this embodiment contains two or more xylylenediamine-based polyamide resins, the refractive index of the xylylenediamine-based polyamide resin is the refractive index of a mixture of the two or more xylylenediamine-based polyamide resins.

[0029] It is also preferable to use a polyamide resin produced using biomass raw materials (biomass polyamide resin) as the xylylenediamine-based polyamide resin. The use of biomass polyamide resins can reduce the environmental impact. Bioadipic acid can be used as the biomass raw material in xylylenediamine-based polyamide resins. Mass-balance certified (ISCC PLUS) adipic acid can also be used. Mass-balance certification means that the amount of renewable raw materials or biomaterials used in each factory or production facility and the amount of products produced or shipped are quantified and guaranteed along with their quality. Xylylenediamine-based polyamide resins using plant-derived dicarboxylic acids, such as sebacic acid, are also suitable as biomass polyamide resins.

[0030] The content of the xylylenediamine-based polyamide resin in the polyolefin resin layer (A) is 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, even more preferably 3% by mass or more, and even more preferably 3.5% by mass or more, based on 100% by mass of the polyolefin resin layer (A). The upper limit of the content of the xylylenediamine-based polyamide resin is 8% by mass or less, preferably 7% by mass or less, and even more preferably 6% by mass or less, based on 100% by mass of the polyolefin resin layer (A). By keeping the content below the upper limit, deterioration of physical properties tends to be suppressed. The polyolefin resin layer (A) in this embodiment may contain only one type of xylylenediamine-based polyamide resin, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range. Furthermore, the xylylenediamine-based polyamide resin in the polyolefin resin layer (A) is preferably 10 parts by mass or less, more preferably 9 parts by mass or less, even more preferably less than 8 parts by mass, still more preferably 6 parts by mass or less, and may be 5 parts by mass or less, and is preferably 2 parts by mass or more, relative to 100 parts by mass of the polyolefin resin contained in the polyolefin resin layer (A).

[0031] <<Acid-Modified Polyolefin Resin>> The polyolefin resin layer (A) in this embodiment contains an acid-modified polyolefin resin. By containing the acid-modified polyolefin resin, the compatibility between the acid-unmodified polyolefin resin and the xylylenediamine-based polyamide resin can be improved, and the decrease in the transparency of the obtained polyolefin resin layer (A) can be suppressed and the decrease in impact resistance can be more effectively suppressed.

[0032] The polyolefin resin constituting the acid-modified polyolefin resin in this embodiment preferably contains a polypropylene resin. The polypropylene resin in this embodiment includes a propylene homopolymer and a polyolefin copolymer copolymerized with less than 50% by mass (preferably 30% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, particularly preferably 3% by mass or less) of another olefin such as ethylene, and a propylene homopolymer is preferred. In the case of a polyolefin copolymer, it may be a block polymer or a random polymer.

[0033] Examples of compounds capable of acid-modifying polyolefin resins include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, methyl maleic acid, methyl fumaric acid, mesaconic acid, citraconic acid, glutaconic acid, cis-4-cyclohexene-1,2-dicarboxylic acid, endobicyclo[2.2.1]-5-heptene-2,3-dicarboxylic acid, and metal salts of these carboxylic acids, monomethyl maleate, monomethyl itaconate, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, and methyl methacrylate. Preferred examples include glycidyl, 2-ethylhexyl methacrylate, hydroxyethyl methacrylate, aminoethyl methacrylate, dimethyl maleate, dimethyl itaconate, maleic anhydride, itaconic anhydride, citraconic anhydride, endobicyclo-[2.2.1]-5-heptene-2,3-dicarboxylic anhydride, maleimide, N-ethylmaleimide, N-butylmaleimide, N-phenylmaleimide, acrylamide, methacrylamide, glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, and glycidyl citraconate. These can be used alone or in combination of two or more. Of these, maleic anhydride is preferred.

[0034] In the present embodiment, the acid-modified polyolefin resin that is particularly preferably used is an acid-modified polypropylene resin, and maleic anhydride-modified polypropylene resin is more preferred.

[0035] The melting point of the acid-modified polyolefin resin is preferably 50°C or higher, more preferably 60°C or higher. By setting the melting point to be equal to or higher than the lower limit, moldability tends to be improved. Furthermore, the melting point of the acid-modified polyolefin resin is preferably 180°C or lower, more preferably 170°C or lower. By setting the melting point to be equal to or lower than the upper limit, moldability tends to be improved. When the polyolefin resin layer in this embodiment contains two or more acid-modified polyolefin resins, the melting point is the melting point of the acid-unmodified polyolefin resin with the largest content.

[0036] The acid-modified polyolefin resin used in this embodiment preferably has a MFR measured in accordance with JIS K7210-1:2014 at 230°C and 2.16 kgf, which is greater than the MFR of the acid-unmodified polyolefin resin. It is presumed that this configuration makes the acid-modified polyolefin resin more compatible with the acid-unmodified polyolefin resin. As a result, it is presumed that the number of contact points between the acid-modified polyolefin resin and the polyamide resin layer in the polyolefin resin layer increases, increasing the proportion of covalent bonds between the acid groups of the acid-modified polyolefin resin and the amino groups of the xylylenediamine-based polyamide resin. The MFR of the acid-modified polyolefin resin, measured in accordance with JIS K7210-1:2014 under conditions of a temperature of 190°C and a pressure of 2.16 kgf, is preferably 1 g / 10 min or more, more preferably 10 g / 10 min or more, even more preferably 50 g / 10 min or more, even more preferably 100 g / 10 min or more, even more preferably 200 g / 10 min or more, even more preferably 300 g / 10 min or more, and particularly preferably 400 g / 10 min or more. By setting the MFR at or above the lower limit, compatibility with the acid-unmodified polyolefin resin tends to be further improved. Furthermore, the MFR of the acid-modified polyolefin resin is preferably 500 g / 10 min or less. By setting the MFR at or below the upper limit, the overall fluidity does not become too high, and moldability tends to be good.

[0037] The content of the acid-modified polyolefin resin in the polyolefin resin layer (A) is 0.1 to 15% by mass, preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 3% by mass or more, even more preferably 4% by mass or more, even more preferably 5% by mass or more, even more preferably 7% by mass or more, and particularly preferably 8% by mass or more, relative to 100% by mass of the polyolefin resin layer (A). By setting the content at or above the lower limit, delamination tends to be suppressed. Furthermore, the upper limit of the content of the acid-modified polyolefin resin in the polyolefin resin layer (A) is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, relative to 100% by mass of the polyolefin resin layer (A). Depending on the application, it may be less than 5% by mass. By setting the content at or below the upper limit, a decrease in transparency tends to be suppressed. The polyolefin resin layer (A) may contain only one type of acid-modified polyolefin resin, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0038] <<Polyamide Resin Having a Refractive Index Difference from the Acid-Unmodified Polyolefin Resin of Less than 0.08>> In this embodiment, the polyolefin resin layer (A) preferably further contains a polyamide resin (hereinafter, sometimes referred to as "another polyamide resin") having a refractive index difference from the acid-unmodified polyolefin resin of less than 0.08. The inclusion of such an other polyamide resin can further improve the transparency of the resulting multilayer body. The type of the other polyamide resin is not particularly limited, and a wide variety of known polyamide resins can be used, as long as the refractive index difference from the acid-unmodified polyolefin resin is less than 0.08. The absolute value of the refractive index difference may be within the upper range, but typically, the refractive index of the acid-unmodified polyolefin resin is less than or equal to the other polyamide resin. The refractive index difference is preferably 0.07 or less, more preferably 0.06 or less, and even more preferably less than 0.06. By keeping the refractive index difference at or below the upper limit, a decrease in transparency tends to be effectively suppressed. The lower limit of the refractive index difference is preferably 0, but may be greater than 0. The refractive index is measured in accordance with JIS K0062 1992. In the case where the polyolefin resin layer (A) in this embodiment contains two or more other polyamide resins, the refractive index of the other polyamide resins is the refractive index of a mixture of the two or more other polyamide resins.

[0039] Specific examples of other polyamide resins include aliphatic polyamide resins and semi-aromatic polyamide resins, with aliphatic polyamide resins being preferred. The aliphatic polyamide resin preferably includes at least one selected from polyamide 6, polyamide 66, and polyamide 666. Examples of semi-aromatic polyamide resins include xylylenediamine-based polyamide resins modified with isophthalic acid (polyamide resins in which more than 30 mol% of dicarboxylic acid-derived structural units are derived from isophthalic acid).

[0040] When the polyolefin resin layer (A) of this embodiment contains another polyamide resin, the content thereof is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, even more preferably 0.3% by mass or more, and even more preferably 0.4% by mass or more, relative to 100% by mass of the polyolefin resin layer (A). The upper limit of the content of the other polyamide resin is preferably 5% by mass or less, more preferably 4.5% by mass or less, even more preferably 4% by mass or less, even more preferably 3% by mass or less, and even more preferably 2% by mass or less, relative to 100% by mass of the polyolefin resin layer (A). By keeping the content below the upper limit, deterioration of physical properties tends to be effectively suppressed. The resin composition of this embodiment may contain only one type of other polyamide resin, or may contain two or more types. When two or more types are contained, the total amount is preferably within the above range.

[0041] <<Other Components>> The polyolefin resin layer (A) in this embodiment may contain other components in addition to those described above, provided that they do not deviate from the spirit of the present invention. Examples of such other components include thermoplastic resins other than polyolefin resins and polyamide resins, inorganic fillers such as glass fibers and carbon fibers, plate-like inorganic fillers such as glass flakes, talc, kaolin, mica, montmorillonite, and organic clay, impact modifiers such as various elastomers, crystal nucleating agents, lubricants such as fatty acid amides and fatty acid amide compounds, antioxidants such as copper compounds, organic or inorganic halogen compounds, hindered phenols, hindered amines, hydrazines, sulfur compounds, and phosphorus compounds, color inhibitors, ultraviolet absorbers such as benzotriazoles, additives such as release agents, plasticizers, colorants, and flame retardants, and additives such as oxidation reaction accelerators, recycling aids, and compounds containing benzoquinones, anthraquinones, and naphthoquinones. The total content of these other components is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and may be 1% by mass or less. For the oxidation reaction accelerator, please refer to the descriptions in paragraphs 0034 to 0036 of WO 2019 / 058986, the contents of which are incorporated herein by reference.

[0042] <<Regrind Material>> The polyolefin resin layer (A) in this embodiment may be formed only from virgin material, or may contain regrind material or recycled material, and preferably contains regrind material. Here, virgin material means a material that has not been subjected to any processing, such as regrind material or recycled material. Usually, various molded products are manufactured from such virgin material. An example of the regrind material is a regrind material of a multilayer structure having a polyolefin resin layer / xylylenediamine-based polyamide resin layer / polyolefin resin layer, and the multilayer structure of this embodiment is preferred.

[0043] That is, the xylylenediamine-based polyamide resin contained in the polyolefin resin layer (A) in this embodiment is preferably a regrind material. In this embodiment, it is preferable that 90 mass % or more and 100 mass % or less of the xylylenediamine-based polyamide resin contained in the polyolefin resin layer (A) is a regrind material.

[0044] In addition, it is preferable that a portion of the acid-unmodified polyolefin resin contained in the polyolefin resin layer (A) in this embodiment is a regrind material. In this embodiment, the proportion of the regrind material in the acid-unmodified polyolefin resin contained in the polyolefin resin layer (A) is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 30% by mass or more, even more preferably 50% by mass or more, and even more preferably 70% by mass or more. By setting it to the lower limit or more, resources can be used effectively from the perspective of environmental consideration. In addition, it is preferable that the proportion of the regrind material in the acid-unmodified polyolefin resin contained in the polyolefin resin layer (A) is 100% by mass or less.

[0045] In addition, it is preferable that a part of the acid-modified polyolefin resin contained in the polyolefin resin layer (A) in this embodiment is a regrind material. In this embodiment, the proportion of the regrind material in the acid-modified polyolefin resin contained in the polyolefin resin layer (A) is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 30% by mass or more, and even more preferably 50% by mass or more. In addition, the proportion of the regrind material in the acid-modified polyolefin resin contained in the polyolefin resin layer (A) is preferably 90% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less. By setting it below the upper limit, deterioration of physical properties tends to be effectively suppressed.

[0046] In addition, a part or all of the other polyamide resin contained in the polyolefin resin layer (A) in this embodiment may be a regrind material. In this embodiment, the proportion of the regrind material in the other polyamide resin contained in the polyolefin resin layer (A) is preferably 90 mass % or more and 100 mass % or less.

[0047] The thickness of the polyolefin resin layer (A) is preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 50 μm or more, and is preferably 2000 μm or less, and even more preferably 1000 μm or less.

[0048] <Barrier Layer (B)> The multilayer body of this embodiment includes a barrier layer (B) containing a barrier resin as a main component. The barrier resin is not particularly limited as long as it has excellent oxygen barrier properties. Specifically, the barrier layer (B) may be a barrier layer having an oxygen permeability coefficient of 0.1 cc mm / (m 2 ·day·atm) or less, and 0.08 cc·mm / (m 2 ·day·atm) or less, and more preferably 0.06 cc·mm / (m 2 The lower limit is preferably 0 cc·mm / (m 2 ·day·atm) is ideal, but 0.001cc·mm / (m 2 A practical oxygen transmission rate is 24 hours (days atm) or more. The oxygen transmission rate (OTR) is measured by forming a film of 50 μm thickness into a film and measuring it in accordance with ASTM D3985 using an oxygen transmission rate measuring device at 23°C and in an atmosphere of relative humidity (60% RH). The unit pressure of the OTR is 1 atm, and the unit transmission time is 24 hours. The oxygen transmission rate (OTR) is measured using an oxygen transmission rate measuring device (manufactured by MOCON, product name: "OX-TRAN (registered trademark) 2 / 21").

[0049] Examples of barrier resins include ethylene-vinyl alcohol copolymers and xylylenediamine-based polyamide resins, with xylylenediamine-based polyamide resins being preferred. Specific examples of ethylene-vinyl alcohol copolymers can be found in paragraphs

[0021] to

[0040] of JP 2023-058469 A, the description of JP 2023-023159 A, and the description of paragraphs

[0011] to

[0016] of JP 2022-074211 A, the contents of which are incorporated herein by reference. The xylylenediamine-based polyamide resin has the same meaning as the xylylenediamine-based polyamide resin described in the section on the polyolefin resin layer (A) above, and the preferred ranges are also the same. In particular, in this embodiment, it is preferred that 90% by mass or more of the xylylenediamine-based polyamide resin contained in the polyolefin resin layer (A) and the xylylenediamine-based polyamide resin contained in the barrier layer (B) have the same composition.

[0050] The barrier layer (B) in this embodiment contains a barrier resin as a main component. The term "main component" means a component contained in the barrier layer (B) in the largest amount. The content of the barrier resin in the barrier layer (B) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, relative to 100% by mass of the barrier layer (B). By setting the content to the above-mentioned lower limit or more, the barrier properties tend to be further improved. Furthermore, the upper limit of the content of the barrier resin in the barrier layer (B) is 100% by mass or less. The barrier layer (B) may contain only one type of barrier resin, or may contain two or more types. When two or more types are contained, the total amount preferably falls within the above-mentioned range.

[0051] The thickness of the barrier layer (B) is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, and is preferably 400 μm or less, more preferably 300 μm or less, and even more preferably 150 μm or less.

[0052] <<Other Components>> The barrier layer (B) in this embodiment may contain other components in addition to those described above, provided that they do not depart from the spirit of the present invention. These other components may include: a thermoplastic resin other than a barrier resin, an inorganic filler such as glass fiber or carbon fiber; a plate-like inorganic filler such as glass flake, talc, kaolin, mica, montmorillonite or organized clay; impact resistance modifiers such as various elastomers; a crystal nucleating agent; a lubricant such as a fatty acid amide or fatty acid amide compound; an antioxidant such as a copper compound, an organic or inorganic halogen compound, a hindered phenol, a hindered amine, a hydrazine, a sulfur-based compound or a phosphorus-based compound; a color inhibitor; an ultraviolet absorber such as a benzotriazole; additives such as a release agent, a plasticizer, a colorant or a flame retardant; an oxidation reaction accelerator, a recycling aid, or a compound containing benzoquinones, an anthraquinone or a naphthoquinone. The total content of these other components is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and may be 1% by mass or less. For the oxidation reaction accelerator, please refer to the descriptions in paragraphs 0034 to 0036 of WO 2019 / 058986, the contents of which are incorporated herein by reference.

[0053] <Layer structure of multilayer body> As described above, the multilayer body of this embodiment has a polyolefin resin layer (A) and a barrier layer (B). When the multilayer body of this embodiment is made into a container (multilayer container), the polyolefin resin layer (A) is usually on the outside. Furthermore, the container (multilayer container) generally has a layer structure of polyolefin resin layer (A) / barrier layer (B) / polyolefin resin layer (A). Hereinafter, variations in the layer structure of the multilayer body of this embodiment will be described with reference to Figure 3. In Figure 3, the same reference numerals are used for components that are common to Figures 1 and 2.

[0054] A first embodiment of the multilayer body of this embodiment is a multilayer body in which a polyolefin resin layer (A) contains a regrind material. Fig. 3(a) shows an example of the first embodiment of the multilayer body, and 51 indicates the polyolefin resin layer (A) containing the regrind material. In Fig. 3(a), the layer structure is polyolefin resin layer (A) 51 / adhesive layer 7 / barrier layer (B) 6 / adhesive layer 7 / polyolefin resin layer (A) 51.

[0055] The polyolefin resin layer (A) containing a regrind material may consist solely of the regrind material, but preferably also contains an acid-unmodified polyolefin resin. By including an acid-unmodified polyolefin resin (particularly, a virgin acid-unmodified polyolefin resin), the proportion of the acid-unmodified polyolefin resin in the polyolefin resin layer (A) can be increased. Furthermore, in addition to the acid-modified polyolefin resin derived from the regrind material, it is also preferable to include an acid-modified polyolefin resin (particularly, a virgin acid-modified polyolefin resin) that is not derived from the regrind material. This configuration can more effectively suppress a decrease in impact resistance while maintaining a decrease in transparency of the resulting multilayer body. Furthermore, in the first embodiment of the multilayer body, as described above, the polyolefin resin layer (A) preferably contains a polyamide resin whose refractive index difference with the acid-unmodified polyolefin resin is less than 0.08. This configuration tends to more effectively suppress a decrease in transparency of the resulting multilayer body.

[0056] The multilayer body of the first embodiment is produced, for example, through a process including melt-kneading a regrind material with a virgin, acid-unmodified polyolefin resin to produce a polyolefin resin layer (A) containing the acid-unmodified polyolefin resin as a main component. The regrind material is preferably regrind material generated during the production of the packaging material of this embodiment, details of which will be described later. The multilayer body of the first embodiment preferably further includes melt-kneading a virgin, acid-modified polyolefin resin in addition to the regrind material and virgin, acid-unmodified polyolefin resin when producing the polyolefin resin layer (A). The polyolefin resin layer (A) and the barrier layer (B) may be co-extruded, but it is preferable to produce films of each and bond them together using an adhesive.

[0057] The adhesive layer 7 is a layer containing an adhesive. The adhesive preferably contains an acid-modified polyolefin. The acid-modified polyolefin is preferably an acid-modified polyolefin modified with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, or maleic anhydride, and more preferably a maleic anhydride-modified polyolefin. An example of the acid-modified polyolefin is the acid-modified polyolefin resin contained in the polyolefin resin layer (A) described above. The adhesive layer preferably contains 80% by mass or more of the adhesive, more preferably 90% by mass or more, and even more preferably 95% by mass or more. The adhesive layer may also contain other components within the scope of the present invention. For details of the adhesive layer, please refer to the descriptions in paragraph 0015 of JP 2012-035504 A and paragraph 0043 of WO 2015 / 083558 A, the contents of which are incorporated herein by reference. The thickness of the adhesive layer is preferably 1 μm or more, more preferably 2 μm or more, and even more preferably 5 μm or more, and is preferably 200 μm or less, and even more preferably 100 μm or less.

[0058] The multilayer body of the first embodiment may further include other layers. Examples of other layers include an oxygen-permeable layer, a sealant layer, and a metal-vapor-deposited layer. For the oxygen-permeable layer, reference may be made to paragraphs 0011 to 0014 of WO 2015 / 083558, the contents of which are incorporated herein by reference. For the sealant layer, reference may be made to paragraph 0045 of WO 2015 / 083558, the contents of which are incorporated herein by reference. For the metal-vapor-deposited layer, reference may be made to an aluminum-vapor-deposited layer. For details of the metal-vapor-deposited layer, reference may be made to the descriptions in WO 2018 / 083962, the contents of which are incorporated herein by reference.

[0059] A second embodiment of the multilayer body has, in addition to a polyolefin resin layer (A) containing a regrind material, a polyolefin resin layer (C) containing an acid-unmodified polyolefin resin as a main component. Figure 3 (b) shows an example of the second embodiment of the multilayer body, in which the multilayer body further contains a polyolefin resin layer (C) containing an acid-unmodified polyolefin resin as a main component. For example, it is a multilayer body containing a polyolefin resin layer (C) containing an acid-unmodified polyolefin resin as a main component, in which the polyolefin resin layer (C), polyolefin resin layer (A), and barrier layer (B) are laminated in this order. More specifically, an example of a multilayer body is one in which the polyolefin resin layer (C) 50 / polyolefin resin layer (A) 51 / adhesive layer 7 / barrier layer (B) 6 / adhesive layer 7 / polyolefin resin layer (A) 51 / polyolefin resin layer (C) 50 are laminated in this order.

[0060] The polyolefin resin layer (C) is a polyolefin resin layer containing an acid-unmodified polyolefin resin as a main component. The content of the acid-unmodified polyolefin resin in the polyolefin resin layer (C) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, relative to 100% by mass of the polyolefin resin layer (C). By setting the content to be equal to or greater than the lower limit, deterioration of transparency tends to be more effectively suppressed. Furthermore, the upper limit of the content of the acid-unmodified polyolefin resin in the polyolefin resin layer (A) is 100% by mass or less. The type of polyolefin resin and other components contained in the polyolefin resin layer (C) are the same as those in the polyolefin resin layer (A). The polyolefin resin contained in the polyolefin resin layer (C) is preferably a virgin polyolefin resin. That is, in a second embodiment of the multilayer body, the polyolefin resin layer (C) contains a virgin polyolefin resin (preferably an acid-unmodified virgin polyolefin resin), the content of the xylylenediamine-based polyamide resin in the polyolefin resin layer (C) is less than 1 mass % (preferably less than 0.1 mass %), and the polyolefin resin layer (A) contains a regrind material. The proportion of the regrind material in the polyolefin resin layer (A) is preferably 1 mass % or more, more preferably 10 mass % or more, and is preferably 40 mass % or less, more preferably 35 mass % or less.

[0061] Also in the second embodiment of the multilayer body, the polyolefin resin layer (A) containing the regrind material may consist solely of the regrind material, but preferably also contains an acid-unmodified polyolefin resin. By including an acid-unmodified polyolefin resin (particularly, a virgin acid-unmodified polyolefin resin), the proportion of acid-unmodified polypropylene resin in the polyolefin resin layer (A) can be increased. Also in the second embodiment of the multilayer body, in addition to the acid-modified polyolefin resin derived from the regrind material, it is preferable to further include an acid-modified polyolefin resin (particularly, a virgin acid-modified polyolefin resin) that is not derived from the regrind material. This configuration can more effectively suppress a decrease in impact resistance while maintaining a decrease in transparency of the resulting multilayer body. Furthermore, also in the second embodiment of the multilayer body, it is preferable that the polyolefin resin layer (A) contains a polyamide resin having a refractive index difference from the acid-unmodified polyolefin resin of less than 0.08, as described above. This configuration tends to more effectively suppress a decrease in transparency of the resulting multilayer body.

[0062] The multilayer body of the second embodiment may include, in addition to the polyolefin resin layer (A), the polyolefin resin layer (C), and the barrier layer (B), other layers such as an adhesive layer, an oxygen-permeable layer, a sealant layer, a metal-deposited layer, etc. For details of these layers, please refer to the description of the multilayer body of the first embodiment.

[0063] <Packaging Material and Packaging Container> The packaging material of this embodiment includes the multilayer body of this embodiment. By including the multilayer body of this embodiment, a packaging material with excellent barrier properties can be obtained. One embodiment of the packaging material is a packaging container. In the multilayer body of this embodiment, the thickness ratio of the polyolefin resin layer (A) to the barrier layer (B) is not particularly limited, but the thickness of one barrier layer (B) is preferably 0.5 to 40, more preferably 1 to 30, when the thickness of one polyolefin resin layer (A) is taken as 100. Furthermore, when the multilayer container of this embodiment has a layer structure of polyolefin resin layer (A) / barrier layer (B) / polyolefin resin layer (A), the thickness of the barrier layer (B) is preferably 1 to 20, more preferably 2 to 15, when the total thickness of the polyolefin resin layer (A) is taken as 100. The thickness of each polyolefin resin layer (A) is preferably 0.2 mm or more, more preferably 0.3 mm or more, and preferably 1.4 mm or less, more preferably 1.0 mm or less. The thickness of each barrier layer (B) is preferably 10 μm or more, more preferably 20 μm or more, and preferably 150 μm or less, more preferably 100 μm or less, and even more preferably 90 μm. The thickness of the multilayer body or multilayer container is preferably 0.4 mm or more, more preferably 0.7 mm or more, and preferably 3 mm or less, more preferably 2 mm or less.

[0064] The multilayer container of this embodiment may be formed by injection molding, two-color molding, or biaxially stretched blow molding, but it is preferable to form a multilayer body and then mold it into the shape of the container. Specifically, it is preferable to soften the multilayer body of this embodiment (especially the multilayer body shown in FIG. 3) with heat and press-molded it. After press-molding, the portion other than the multilayer container (waste material) can be reused as regrind material.

[0065] <Uses> The packaging material or packaging container of this embodiment can be preferably used for container lids, bottles, cups, trays, tubes, etc. The packaging material or packaging container of this embodiment can be preferably used for packaging and storing medicines, foods (processed seafood products, processed livestock products, rice dishes, liquid foods), etc. For details, please refer to paragraphs 0033 to 0035 of JP 2011-37199 A, the contents of which are incorporated herein by reference. In particular, as a transparent container, it is preferably used as a container for retort foods or foods to be boiled.

[0066] The present invention will be explained in more detail below with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or the like, measurements can be made using other instruments with equivalent performance.

[0067] 1. Raw Materials <Acid-Unmodified Polyolefin Resin> PP: Polypropylene resin, manufactured by Prime Polymer Co., Ltd., E222, refractive index: 1.49, MFR measured in accordance with JIS K7210-1:2014 under conditions of 230°C and 2.16 kgf: 1.5 g / 10 min, melting point: 145°C

[0068] <Barrier Resin> MX Nylon: S6007 manufactured by Mitsubishi Gas Chemical Company, Inc., polyamide resin synthesized from metaxylylenediamine and adipic acid, refractive index: 1.57, melting point: 237°C

[0069] <Polyamide resin> PA6: Polyamide 6, manufactured by Ube Industries, product number: 1024B, refractive index: 1.54 PA666: Polyamide 666, manufactured by DSM, product number: 2030FC, refractive index: 1.54 PA6IT: Polyamide 6I / 6T, manufactured by EMS, product number: G21, refractive index: 1.59

[0070] <Acid-Modified Polyolefin Resin> The maleic anhydride-modified polypropylene resins shown in Table 1 below were used.

[0071] The MFR means the melt flow rate measured in accordance with JIS K7210-1:2014 under conditions of 190°C and 2.16 kgf.

[0072] 2. Reference Example, Comparative Example 1, Examples 1 to 8 <Production of Regrind Material> As shown in Table 2 or Table 3, an acid-unmodified polyolefin resin and, if necessary, a barrier resin, a polyamide resin, and an acid-modified polyolefin resin (each component is shown in parts by mass) were blended, and the blend was extruded at 253°C in a twin-screw extruder to form pellets.

[0073] <Film Production> Using the regrind material pellets obtained above, films (thicknesses 200 μm, 100 μm) containing 100% regrind material were produced by extrusion in a uniaxial film forming machine at 225° C. and a roll temperature of 35° C. In addition, a film (thickness 200 μm) using 50% by mass of the regrind material pellets and 50% by mass of virgin PP (E222, manufactured by Prime Polymer Co., Ltd.), a film (thickness 200 μm) using 30% by mass of the regrind material pellets and 70% by mass of virgin PP, and a film (thickness 200 μm) using 10% by mass of the regrind material pellets and 90% by mass of virgin PP were produced under the same conditions as above.

[0074] <Impact Test Impact Value Retention Rate> The impact test impact value of the film (thickness 200 μm, 100 μm) containing 100% by mass of the regrind material obtained above was measured, and the retention rate (unit: %) was expressed relative to the impact impact value of the Reference Example (film containing 100% by mass of virgin PP) being 100%. The impact test impact value was measured using a Tosoku Precision Industry IFT-60.

[0075] <Haze> The haze of each film (thickness: 200 μm) containing 100 mass %, 50 mass %, 30 mass %, and 10 mass % of the regrind material obtained above was measured using a Nippon Denshoku Industries COH400.

[0076]

[0077]

[0078] As is clear from the above results, even when the polyolefin resin layer (A) contained a xylylenediamine-based polyamide resin, by incorporating an acid-modified polyolefin resin, it was possible to effectively suppress a decrease in transparency while maintaining high impact resistance (Examples 1 to 8). In particular, by incorporating a polyamide resin whose refractive index difference with the acid-unmodified polyolefin resin was less than 0.08, it was possible to effectively suppress a decrease in transparency (Comparison of Examples 4 to 7 with other Examples).

[0079] DESCRIPTION OF SYMBOLS 1 Raw material 2 Container formed by processing raw material 3 Material remaining after raw material is cut out 4 Regrind material 5 Polyolefin resin layer 6 Barrier layer 7 Adhesive layer 50 Polyolefin resin layer (C) 51 Polyolefin resin layer (A)

Claims

1. A multilayer body having a polyolefin resin layer (A) containing an acid-unmodified polyolefin resin as a main component and a barrier layer (B) containing a barrier resin as a main component, wherein the polyolefin resin layer (A) contains 0.1 to 8 mass % of a xylylenediamine-based polyamide resin and 0.1 to 15 mass % of an acid-modified polyolefin resin, and the xylylenediamine-based polyamide resin contains diamine-derived structural units and dicarboxylic acid-derived structural units, wherein 70 mol % or more of the diamine-derived structural units are derived from xylylenediamine, and 70 mol % or more of the dicarboxylic acid-derived structural units are derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms.

2. The multilayer body according to claim 1, wherein the acid-unmodified polyolefin resin contained in the polyolefin resin layer (A) comprises an acid-unmodified polypropylene resin.

3. The multilayer body according to claim 1 or 2, wherein the acid-modified polyolefin resin contained in the polyolefin resin layer (A) comprises a maleic anhydride-modified polypropylene resin.

4. The multilayer body according to any one of claims 1 to 3, wherein the polyolefin resin layer (A) further contains a polyamide resin having a refractive index difference of less than 0.08 from that of an acid-unmodified polyolefin resin.

5. The multilayer body according to claim 4, wherein the polyamide resin having a refractive index difference of less than 0.08 from the acid-unmodified polyolefin resin comprises at least one selected from polyamide 6, polyamide 66 and polyamide 666.

6. The multilayer body according to any one of claims 1 to 5, wherein the xylylenediamine-based polyamide resin contained in the polyolefin resin layer (A) is a regrind material.

7. The multilayer body according to any one of claims 1 to 6, wherein the barrier resin contained in said barrier layer (B) is a xylylenediamine-based polyamide resin, said xylylenediamine-based polyamide resin comprises diamine-derived structural units and dicarboxylic acid-derived structural units, 70 mol % or more of said diamine-derived structural units being derived from xylylenediamine, and 70 mol % or more of said dicarboxylic acid-derived structural units being derived from an α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms.

8. The multilayer body according to any one of claims 1 to 7, wherein the acid-unmodified polyolefin resin contained in said polyolefin resin layer (A) comprises a maleic anhydride-modified polypropylene resin, said polyolefin resin layer (A) further comprises a polyamide resin having a refractive index difference of less than 0.08 from said acid-unmodified polyolefin resin, and said polyamide resin having a refractive index difference of less than 0.08 from said acid-unmodified polyolefin resin comprises at least one selected from polyamide 6, polyamide 66 and polyamide 666, said xylylenediamine-based polyamide resin contained in said polyolefin resin layer (A) is a regrind material, and said barrier resin contained in said barrier layer (B) is a xylylenediamine-based polyamide resin, said xylylenediamine-based polyamide resin comprises diamine-derived structural units and dicarboxylic acid-derived structural units, wherein 70 mol % or more of said diamine-derived structural units are derived from xylylenediamine and 70 mol % or more of said dicarboxylic acid-derived structural units are derived from α,ω-linear aliphatic dicarboxylic acid having 4 to 20 carbon atoms.

9. The multilayer body according to any one of claims 1 to 8, further comprising a polyolefin resin layer (C) containing an acid-unmodified polyolefin resin as a main component, the polyolefin resin layer (C), the polyolefin resin layer (A), and the barrier layer (B) being laminated in this order.

10. A packaging material comprising the multilayer body according to any one of claims 1 to 9.

11. The packaging material according to claim 10, which is for a container.

12. A method for producing the packaging material according to claim 10 or 11, comprising melt-kneading regrind material generated during the production of the packaging material according to claim 10 or 11 with virgin acid-unmodified polyolefin resin to produce a polyolefin resin layer (A) containing the acid-unmodified polyolefin resin as a main component.

13. A method for producing a packaging material according to claim 12, comprising melt-kneading a virgin acid-modified polyolefin resin in addition to the regrind material and virgin acid-unmodified polyolefin resin when producing the polyolefin resin layer (A).

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