Polymer composition and molded article thereof

Abstract

To provide a polymer composition capable of reducing occurrence of a foreign matter in an extrusion process and excellent in transparency and cycle characteristics, in a recycled composition of multilayer packages using a nonpolar polymer such as polyolefins and a barrier polar polymer such as an ethylene-vinyl alcohol-based copolymer.SOLUTION: A polymer composition comprises, relative to 100 pts.mass of a polyolefin-based polymer (a), at least one polar polymer (b) selected from an ethylene-vinyl alcohol copolymer (b1) and a polyamide polymer (b2) in an amount of 0.1 to 20 pts.mass, and acid modified polyolefin (d) in an amount of 0.1 to 25 pts.mass. The acid-modified polyolefin (d) is a modified ethylene copolymer obtained by modifying a copolymer of an ethylene monomer and one or two or more of α-olefine monomers of 4 to 8 carbon atoms with unsaturated carboxylic acid and / or its anhydride, and the melt flow rate of the modified ethylene copolymer (MFR: 190°C, 2.16 kg) is 15 to 39 g / 10 minutes.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polymer composition. The present invention also relates to a molded article and a multi-layer packaging material obtained by molding the polymer composition. [Background technology]

[0002] For the purpose of reducing the amount of plastic packaging waste, a recycling technology is known in which the following polymer composition is granulated / molded and reused as a regrind layer or recycled layer of a multi-layer packaging material. A polymer composition made by melt-kneading recycled scraps generated during the manufacturing process of multi-layer packaging materials using non-polar polymers such as polyolefins and polar barrier polymers such as ethylene-vinyl alcohol copolymer (EVOH), as well as recycled multi-layer packaging materials that have been manufactured and then pulverized to fine particles by grinding or other methods. However, the ethylene-vinyl alcohol copolymer and polyolefin in the polymer composition obtained in this way are poorly compatible. As a result, the ethylene-vinyl alcohol copolymer aggregates in the regrind layer or recycled layer, causing a decrease in transparency and mechanical strength, which affects the quality of the recycled multilayer packaging material. This has resulted in poor recyclability when such recycling is repeated.

[0003] To address this problem, it is known to use a specific maleic anhydride-modified ethylene copolymer as a compatibilizer for compatibilizing ethylene-vinyl alcohol copolymer and polyolefin. For example, Patent Documents 1 and 2 specifically describe a maleic anhydride-modified ethylene-octene copolymer as a maleic anhydride-modified ethylene copolymer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2014 / 070237 [Patent Document 2] International Publication No. 2016 / 109023 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned recycling process, the transparency of the resulting polymer composition is improved by preparing a polymer composition containing an ethylene-vinyl alcohol copolymer, a polyolefin, and a maleic anhydride-modified ethylene copolymer, specifically a maleic anhydride-modified ethylene-octene copolymer, as described in Patent Documents 1 and 2. However, during the extrusion process in which the polymer composition is melt-mixed and then granulated / molded, a problem of foreign matter (sometimes called "eye mucus") adhering near the extrusion outlet (die head) can occur. When foreign matter adheres near the extrusion outlet, removing it can reduce productivity. Furthermore, the presence of foreign matter in the polymer composition after granulation / molding can also reduce the quality of the granulated / molded product. Furthermore, repeated reuse as a regrind layer or recycled layer in a multilayer packaging material can lead to a problem of reduced recyclability, depending on the type of polyolefin.

[0006] The present invention has been made in view of the above problems, and its object is to provide a polymer composition that is highly recyclable, which can reduce the generation of foreign matter in the extrusion process and can give molded products with excellent transparency, in a polymer composition obtained when recycling scraps generated in the manufacturing process of a multilayer packaging material using a non-polar polymer such as polyolefin and a polar polymer with barrier properties such as an ethylene-vinyl alcohol copolymer, or when recycling manufactured multilayer packaging materials. [Means for solving the problem]

[0007] As a result of extensive research aimed at solving the above-mentioned problems, the inventors discovered that the generation of foreign matter during the extrusion process can be reduced by using a specific acid-modified polyolefin in a predetermined ratio relative to a polyolefin polymer and a polar polymer, such as an ethylene-vinyl alcohol copolymer and / or a polyamide polymer, and thus arrived at the present invention. That is, the present invention has the following features.

[0008] [1] A polymer composition comprising, per 100 parts by mass of a polyolefin polymer (a), 0.1 to 20 parts by mass of at least one polar polymer (b) selected from an ethylene-vinyl alcohol copolymer (b1) and a polyamide polymer (b2), and 0.1 to 25 parts by mass of an acid-modified polyolefin (d), wherein the acid-modified polyolefin (d) is a modified ethylene copolymer obtained by modifying a copolymer of an ethylene monomer and one or more α-olefin monomers having 4 to 8 carbon atoms with an unsaturated carboxylic acid and / or an anhydride thereof, and the modified ethylene copolymer has a melt flow rate (MFR: 190°C, 2.16 kg) of 15 to 39 g / 10 min.

[0009] [2] The polymer composition according to [1], further comprising an acid-modified polyolefin (c) having a melt flow rate (MFR: 190°C, 2.16 kg) of 0.01 g / 10 min or more and less than 15 g / 10 min.

[0010] [3] The polymer composition according to [2], wherein the content of the acid-modified polyolefin (c) is 0.1 to 20 parts by mass per 100 parts by mass of the polyolefin polymer (a).

[0011] [4] The density of the acid-modified polyolefin (d) is 0.855 to 0.895 g / cm 3 The polymer composition according to any one of [1] to [3], wherein

[0012] [5] The polymer composition according to any one of [1] to [4], wherein the graft ratio of the acid-modified polyolefin (d) is 0.1 to 1.0% by mass.

[0013] [6] The polymer composition according to any one of [1] to [5], wherein the acid-modified polyolefin (d) is a modified ethylene-butene copolymer.

[0014] [7] The polymer composition according to any one of [1] to [6], wherein the polyolefin polymer (a) is polyethylene.

[0015] [8] The polymer composition according to any one of [1] to [7], wherein the polar polymer (b) is an ethylene-vinyl alcohol copolymer (b1) having an ethylene unit content of 20 mol% or more and less than 50 mol%.

[0016] [9] A molded article obtained by molding the polymer composition according to any one of [1] to [8].

[0017]

[10] A multilayer packaging material having a layer containing the polymer composition according to any one of [1] to [8].

[0018]

[11] A method for producing a polymer composition according to any one of [1] to [8], comprising a step of melt-kneading the polyolefin polymer (a), at least one polar polymer (b) selected from the ethylene-vinyl alcohol copolymer (b1) and the polyamide polymer (b2), and the acid-modified polyolefin (d).

[0019]

[12] A method for producing the multilayer packaging material described in

[10] , comprising a step of melt-molding the polyolefin polymer (a), at least one polar polymer (b) selected from the ethylene-vinyl alcohol copolymer (b1) and the polyamide polymer (b2), and the acid-modified polyolefin (d). [Effects of the Invention]

[0020] The polymer composition of the present invention reduces the generation of foreign matter during the extrusion process without impairing the transparency of the polymer composition (hereinafter sometimes referred to as the "recycled composition" or "regrind composition") obtained when recycling scraps generated during the manufacturing process of a multilayer packaging material using a polyolefin polymer and a barrier polar polymer such as an ethylene-vinyl alcohol copolymer and / or a polyamide polymer, or the manufactured multilayer packaging material, and this effect can be maintained even when such recycling is repeated (hereinafter this effect can be referred to as "recyclability").

[0021] According to the polymer composition of the present invention, even when recycling is repeated, the generation of foreign matter in the extrusion step can be reduced, and therefore, molded articles such as multi-layer packaging materials having excellent transparency can be molded with high yield and high production efficiency without the problem of foreign matter contamination. However, the polymer composition of the present invention is not limited to those containing a polyolefin polymer and an ethylene-vinyl alcohol copolymer and / or a polyamide polymer as recycled materials, and can be effectively applied even when one or both of these are virgin resins. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following describes in detail the embodiments of the present invention, but the present invention is not limited to the following description and can be implemented by any modifications within the scope of the gist of the present invention. In this specification, when a numerical value or physical property value is enclosed by "~", the values ​​before and after the "~" are used to include the values ​​before and after the "~"

[0023] Hereinafter, the monomer units contained in the copolymer may be simply referred to as "units." For example, a monomer unit based on propylene may be referred to as a "propylene unit," and a monomer unit based on ethylene and a monomer unit based on an α-olefin may be referred to as an "ethylene unit" and an "α-olefin unit," respectively.

[0024] In the present invention, the melt flow rate (MFR) of the polymer, the density, and the graft ratio of the modified polymer are values ​​measured as follows.

[0025] <mfr> According to JIS K7210, the test is carried out at 190°C (for ethylene polymers among polyolefin polymers (a), acid-modified polyolefins (c), and acid-modified polyolefins (d)) or 210°C (for propylene polymers among polyolefin polymers (a), ethylene-vinyl alcohol copolymers (b1), and polyamide polymers (b2)) under a load of 2.16 kg.

[0026] <density> It is measured by the underwater displacement method according to JIS K7112.

[0027] <Grafting rate> The graft ratio (also referred to as the modification amount or graft amount) of a modified polymer such as an acid-modified polyolefin means the content of unsaturated carboxylic acid and / or its anhydride (hereinafter sometimes referred to as "unsaturated carboxylic acid component") grafted to a raw polymer described below, when measured with an infrared spectrometer. The content of the unsaturated carboxylic acid component can be measured, for example, by measuring the absorption characteristic of the unsaturated carboxylic acid component, specifically, 1,900 to 1,600 cm, in a sample obtained by press-molding the modified polymer into a sheet having a thickness of about 100 μm. -1 The graft ratio can be determined by measuring the carbonyl characteristic absorption (C=O stretching vibration band). The graft ratio can also be determined from a calibration curve prepared in advance by the above method.

[0028] [Polymer composition] The polymer composition of the present invention is a polymer composition containing, relative to 100 parts by mass of a polyolefin polymer (a), 0.1 to 20 parts by mass of at least one polar polymer (b) selected from an ethylene-vinyl alcohol copolymer (b1) (hereinafter, sometimes referred to as "EVOH (b1)") and a polyamide polymer (b2), and 0.1 to 25 parts by mass of an acid-modified polyolefin (d). The acid-modified polyolefin (d) is a modified ethylene copolymer obtained by modifying a copolymer of an ethylene monomer and one or more α-olefin monomers having 4 to 8 carbon atoms with an unsaturated carboxylic acid and / or an anhydride thereof, and is characterized in that the melt flow rate (MFR: 190°C, 2.16 kg) of the modified ethylene copolymer is 15 to 39 g / 10 min. The polymer composition of the present invention may further contain, if necessary, an acid-modified polyolefin (c) having a melt flow rate different from that of the acid-modified polyolefin (d).

[0029] [Polyolefin polymer (a)] Examples of the polyolefin polymer (a) include polypropylene; propylene copolymers obtained by copolymerizing propylene with an α-olefin such as ethylene, 1-butene, 1-hexene, or 4-methyl-1-pentene; polyethylenes such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, and high-density polyethylene; ethylene copolymers obtained by copolymerizing ethylene with an α-olefin such as 1-butene, 1-hexene, or 4-methyl-1-pentene; poly(1-butene), poly(4-methyl-1-pentene), and the like.

[0030] The polyolefin polymer (a) may be used singly or in the form of a mixture of two or more different copolymer components and physical properties.

[0031] Among these, preferred polyolefin polymers (a) are propylene polymers such as polypropylene and propylene copolymers, and ethylene polymers such as polyethylene and ethylene copolymers. From the viewpoint of obtaining molded articles with excellent heat resistance, preferred polyolefin polymers (a) are propylene polymers, and more preferred polypropylene. On the other hand, from the viewpoint of obtaining molded articles with excellent transparency, preferred polyolefin polymers (a) are ethylene polymers, and more preferred polyethylene, and even more preferred high-density polyethylene.

[0032] The melt flow rate (MFR: 190°C or 210°C, 2.16 kg) of the polyolefin polymer (a) is preferably 0.01 to 10 g / 10 min. When the MFR of the polyolefin polymer (a) is 0.01 g / 10 min or more, the difference in melt viscosity between the polar polymer (b) and the polyolefin polymer (a) is not too large, the dispersibility of the polar polymer (b) in the polymer composition is good, and the impact resistance of the resulting molded article is excellent. On the other hand, when the MFR of the polyolefin polymer (a) is 10 g / 10 min or less, the impact resistance of the resulting molded article is good. The MFR of the polyolefin polymer (a) is more preferably 5 g / 10 min or less, even more preferably 3 g / 10 min or less, and particularly preferably 2 g / 10 min or less. When the polyolefin polymer (a) is a mixture of multiple polymers, the MFR of the polyolefin polymer (a) is the weighted average of the MFRs of the individual polymers based on the blend mass ratio. When the EVOH (b1), polyamide polymer (b2), acid-modified polyolefin (c), and acid-modified polyolefin (d) described below are mixtures of multiple types of polymers, the MFR of each is determined in the same manner as for the polyolefin polymer (a).

[0033] [Polar polymer (b)] The polar polymer (b) is at least one barrier polar polymer selected from EVOH (b1) and polyamide polymers (b2). The polar polymer (b) may be a mixture of one or more EVOHs (b1) and one or more polyamide polymers (b2). When a mixture of EVOHs (b1) and polyamide polymers (b2) is used, there is no particular limitation on the mixing ratio.

[0034] <EVOH(b1)> EVOH (b1) can be obtained by saponifying an ethylene-vinyl ester copolymer. A typical example of a vinyl ester is vinyl acetate, but other fatty acid vinyl esters (such as vinyl propionate and vinyl pivalate) can also be used. Ethylene-vinyl ester copolymers can be produced by any known polymerization method, such as solution polymerization, suspension polymerization, or emulsion polymerization, and saponification of ethylene-vinyl ester copolymers can also be carried out by known methods.

[0035] The ethylene unit content of EVOH (b1), as measured in accordance with ISO 14663, is preferably 20 to 60 mol%. When the ethylene unit content is 20 mol% or more, the gas barrier property and melt moldability of EVOH (b1) in the polymer composition at high humidity are good. The ethylene unit content of EVOH (b1) is more preferably 23 mol% or more. Furthermore, when the ethylene unit content is 60 mol% or less, the barrier property is excellent. The ethylene unit content of EVOH (b1) is more preferably 55 mol% or less, even more preferably 50 mol% or less, and particularly preferably less than 50 mol%.

[0036] The degree of saponification of the vinyl ester units of EVOH (b1) is a value measured in accordance with JIS K6726 (wherein EVOH is a solution uniformly dissolved in a water / methanol solvent), and from the viewpoints of barrier properties, thermal stability, and moisture resistance, it is preferably 80 mol% or more, more preferably 98 mol% or more, and even more preferably 99 mol% or more.

[0037] The melt flow rate (MFR: 210°C, 2.16 kg) of EVOH (b1) is preferably 0.1 to 100 g / 10 min. When the MFR of EVOH (b1) is 100 g / 10 min or less, the difference in melt viscosity between EVOH (b1) and the acid-modified polyolefin (c) is not too large, the dispersibility of EVOH (b1) in the polymer composition is good, and the thermal stability is excellent. The MFR of EVOH (b1) is more preferably 50 g / 10 min or less, and even more preferably 30 g / 10 min or less. On the other hand, when the MFR of EVOH (b1) is 0.1 g / 10 min or more, the difference in viscosity from the acid-modified polyolefin (d) is not too large, the dispersibility of EVOH (b1) in the polymer composition is good, and the impact resistance is good. The MFR of EVOH (b1) is more preferably 0.5 g / 10 min or more.

[0038] EVOH (b1) may be copolymerized with polymerizable monomers other than ethylene and vinyl esters, generally in an amount of 5 mol% or less, so long as the effects of the present invention are not impaired. Examples of such polymerizable monomers include α-olefins such as propylene, isobutene, α-octene, α-dodecene, and α-octadecene; hydroxyl-containing α-olefins such as 3-buten-1-ol, 4-penten-1-ol, and 3-butene-1,2-diol, as well as hydroxyl-containing α-olefin derivatives such as their esters and acylation products; hydroxymethylvinylidene diacetates such as 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane, and 1,3-dibutyronyloxy-2-methylenepropane; unsaturated carboxylic acids or their salts, partial alkyl esters, complete alkyl esters, nitriles, amides, or anhydrides; unsaturated sulfonic acids or their salts; vinylsilane compounds; vinyl chloride; and styrene.

[0039] Furthermore, as the EVOH (b1), EVOH that has been "post-modified" by urethanization, acetalization, cyanoethylation, oxyalkylenation, or the like can also be used.

[0040] The EVOH (b1) may be used alone or in combination with two or more types of vinyl esters differing in type, ethylene unit content, physical properties, etc.

[0041] <Polyamide polymer (b2)> As the polyamide polymer (b2), known polymers can be used. Specific examples include homopolymers such as polycapramide (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-ω-aminononanoic acid (nylon 9), polyundecaneamide (nylon 11), and polylauryllactam (nylon 12). In addition, polyamide copolymers include polyethylene diamine adipamide (nylon 26), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyoctamethylene adipamide (nylon 86), polydecamethylene adipamide (nylon 108), caprolactam / lauryl laureth Lauryl lactam copolymer (nylon 6 / 12), caprolactam / ω-aminononanoic acid copolymer (nylon 6 / 9), caprolactam / hexamethylenediammonium adipate copolymer (nylon 6 / 66), lauryllactam / hexamethylenediammonium adipate copolymer (nylon 12 / 66), ethylenediamine adipamide / hexamethylenediammonium adipate copolymer (nylon 26 / 66), caprolactam / hexamethylenediammonium adipate copolymer (nylon 26 / 66), Examples of suitable polyamides include aliphatic polyamides such as ethylene diammonium adipate / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer (nylon 66 / 610) and ethylene ammonium adipate / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer (nylon 6 / 66 / 610), aromatic polyamides such as polyhexamethylene isophthalamide, polyhexamethylene terephthalamide, polymetaxylylene adipamide, hexamethylene isophthalamide / terephthalamide copolymer, poly-p-phenylene terephthalamide, and poly-p-phenylene-3,4'-diphenyl ether terephthalamide, amorphous polyamides, and polyamide-based polymers modified with aromatic amines such as methylenebenzylamine and metaxylylene diamine, metaxylylene diammonium adipate, and terminal-modified polyamide-based polymers thereof. Among these, terminal-modified polyamide-based polymers are preferred.

[0042] The polyamide polymer (b2) preferably has a melt flow rate (MFR: 210°C, 2.16 kg) of 0.1 to 30 g / 10 min. When the MFR of the polyamide polymer (b2) is within the above range, it can optimally react with the acid-modified polyolefin (d) serving as a compatibilizer, thereby improving dispersibility.

[0043] The polyamide polymer (b2) may be used alone or in combination of two or more types having different copolymer compositions, physical properties, etc.

[0044] [Acid-modified polyolefin (c)] Examples of the acid-modified polyolefin (c) include graft-modified polyolefins obtained by graft-modifying polyolefins with acids, and olefin copolymers obtained by copolymerizing olefins with acids. These may be used alone or in combination of two or more. Among these, the acid-modified polyolefin (c) is preferably a modified polyolefin modified with an unsaturated carboxylic acid and / or a derivative thereof, and from the viewpoint of excellent compatibility with the polyolefin polymer (a), the acid-modified polyolefin (c) is preferably a polyolefin polymer of the same type as the polyolefin polymer (a) that has been acid-modified. For example, when the polyolefin polymer (a) is polypropylene, the acid-modified polyolefin (c) is preferably acid-modified polypropylene, and when the polyolefin polymer (a) is polyethylene, the acid-modified polyolefin (c) is preferably acid-modified polyethylene.

[0045] Examples of unsaturated carboxylic acids used for graft-modifying the acid-modified polyolefin (c) include acrylic acid, methacrylic acid, fumaric acid, itaconic acid, and maleic acid. Examples of derivatives of unsaturated carboxylic acids include acid anhydrides such as maleic anhydride and itaconic anhydride. Of these, maleic anhydride is most suitable.

[0046] The melt flow rate (MFR: 190°C, 2.16 kg) of the acid-modified polyolefin (c) is 0.01 g / 10 min or more and less than 15 g / 10 min, preferably 0.5 to 10 g / 10 min. When the MFR of the acid-modified polyolefin (c) is within the above range, a good balance of the viscosities of the acid-modified polyolefin (c), the polyolefin polymer (a), and the acid-modified polyolefin (d) is achieved. As a result, the dispersibility of the polar polymer (b) is improved, and the impact resistance of the molded article is improved.

[0047] The density of the acid-modified polyolefin (c) is 0.855 to 0.955 g / cm 3 When the density of the acid-modified polyolefin (c) is within the above range, the generation of foreign matter in the extrusion step can be reduced without impairing transparency, and the appearance of the recycled film can be maintained good, while the deterioration of mechanical properties can be prevented.

[0048] The amount of unsaturated carboxylic acid and / or derivative thereof contained in the acid-modified polyolefin (c) is preferably 0.001 to 3 mass % of the acid-modified polyolefin (c). When the amount of unsaturated carboxylic acid and / or derivative thereof in the acid-modified polyolefin (c) is within the above range, the dispersibility of the polar polymer (b) in the polymer composition of the present invention is improved, and the moldability is improved.

[0049] The acid-modified polyolefin (c) may be used alone or in combination of two or more kinds of polymers different in type and physical properties before modification.

[0050] [Acid-modified polyolefin (d)] The acid-modified polyolefin (d) is a modified ethylene copolymer obtained by modifying a copolymer of ethylene monomer and one or more α-olefin monomers having 4 to 8 carbon atoms (hereinafter sometimes referred to as "ethylene copolymer" or "raw polymer") with an unsaturated carboxylic acid and / or its anhydride (unsaturated carboxylic acid component), and the melt flow rate (MFR: 190°C, 2.16 kg) of the modified ethylene copolymer is 15 to 39 g / 10 min.

[0051] By using such an acid-modified polyolefin (d), the polar polymer (b) can be finely dispersed in the polyolefin polymer (a), which is a non-polar polymer, and as a result, the mechanical strength and transparency of the polyolefin polymer (a) can be improved in the recycled composition in which the polar polymer (b) is dispersed.

[0052] The acid-modified polyolefin (d) has an MFR (190°C, load 2.16 kg) of 15 to 39 g / 10 min. By setting the MFR of the acid-modified polyolefin (d) within the above range, it is possible to reduce the generation of foreign matter in the extrusion process without impairing transparency, and it is possible to maintain a good appearance of the film obtained by molding the recycled composition (hereinafter, sometimes referred to as "recycled film") and prevent a decrease in mechanical properties.

[0053] The density of the acid-modified polyolefin (d) is preferably 0.855 to 0.895 g / cm 3 By setting the density of the acid-modified polyolefin (d) within the above range, it is possible to reduce the generation of foreign matter during the extrusion process without impairing transparency, and it is possible to maintain a good appearance of the recycled film and prevent a decrease in mechanical properties.

[0054] <Modified ethylene copolymer> Examples of the α-olefin monomer having 4 to 8 carbon atoms constituting the modified ethylene copolymer of the acid-modified polyolefin (d) include one or more of 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 4,4-dimethyl-1-pentene, 1-hexene, 4-methyl-1-hexene, 1-heptene, and 1-octene. Among these, α-olefin monomers having 4 to 6 carbon atoms are preferred, and an α-olefin monomer having 4 carbon atoms, i.e., 1-butene, is particularly preferred.

[0055] Examples of modified ethylene copolymers include modified ethylene-butene copolymers, modified ethylene-hexene copolymers, and modified ethylene-octene copolymers. Among these, from the viewpoint of recyclability, modified ethylene-butene copolymers and modified ethylene-hexene copolymers are preferred, and modified ethylene-butene copolymers are particularly preferred.

[0056] Furthermore, the modified ethylene copolymer may contain other monomer units in addition to the ethylene monomer and the above-mentioned α-olefin monomer.

[0057] <Ethylene copolymer> The ethylene copolymer to be modified with the unsaturated carboxylic acid component is not particularly limited as long as the above-mentioned modified ethylene copolymer can be obtained, and any known ethylene copolymer can be used.

[0058] The MFR (190°C, load 2.16 kg) of the ethylene copolymer to be modified, i.e., the raw polymer, is not particularly limited, but is preferably 18 to 50 g / 10 min. By setting the MFR of the raw polymer within the above range, the desired modified ethylene copolymer tends to be more easily obtained, even when taking into account changes in MFR due to modification.

[0059] The raw polymer has a density of 0.855 to 0.895 g / cm 3 The following can be suitably used.

[0060] As the raw material polymer suitable for the present invention, commercially available products can be used, and for example, a polymer having the above-mentioned properties can be appropriately selected from the "TAFMER (registered trademark)" series manufactured by Mitsui Chemicals, Inc. and used.

[0061] In the present invention, the ethylene copolymer as the raw material polymer may be used alone or in combination of two or more types having different physical properties, compositions, etc.

[0062] <Graft modification> Examples of unsaturated carboxylic acids for graft-modifying the ethylene copolymer include α,β-ethylenically unsaturated carboxylic acids such as acrylic acid, maleic acid, fumaric acid, tetrahydrofumaric acid, itaconic acid, citraconic acid, crotonic acid, and isocrotonic acid. Examples of anhydrides of unsaturated carboxylic acids include succinic acid 2-octen-1-yl anhydride, succinic acid 2-dodecen-1-yl anhydride, succinic acid 2-octadecen-1-yl anhydride, maleic acid anhydride, 2,3-dimethylmaleic acid anhydride, bromomaleic acid anhydride, dichloromaleic acid anhydride, citraconic acid anhydride, itaconic acid anhydride, 1-butene-3,4-dicarboxylic acid anhydride, 1-cyclopentene-1,2-dicarboxylic acid anhydride, and 1,2,3,6-tetrahydrophthalic acid. Examples of unsaturated carboxylic acid anhydrides include 3,4,5,6-tetrahydrophthalic anhydride, exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, methyl-5-norbornene-2,3-dicarboxylic anhydride, endo-bicyclo[2.2.2]oct-5-ene-2,3-dicarboxylic anhydride, and bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic anhydride.

[0063] These unsaturated carboxylic acid components can be appropriately selected depending on the ethylene copolymer to be modified and the modification conditions, and may be used alone or in combination of two or more. These unsaturated carboxylic acid components can also be used by dissolving them in an organic solvent or the like.

[0064] The graft modification of the ethylene copolymer can be carried out by adding an unsaturated carboxylic acid component and graft polymerizing the unsaturated carboxylic acid component onto the ethylene copolymer, preferably in the presence of a radical generator.

[0065] Examples of the radical generator used herein include organic and inorganic peroxides such as t-butyl hydroperoxide, cumene hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 2,5-dimethyl-2,5-bis(t-butyloxy)hexane, 3,5,5-trimethylhexanoyl peroxide, t-butyl peroxybenzoate, benzoyl peroxide, m-toluoyl peroxide, dicumyl peroxide, 1,3-bis(t-butylperoxyisopropyl)benzene, dibutyl peroxide, methyl ethyl ketone peroxide, potassium peroxide, and hydrogen peroxide; azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(isobutylamido)dihalide, 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide] and azodi-t-butane; and carbon radical generators such as dicumyl.

[0066] The radical generator can be appropriately selected depending on the type of ethylene copolymer to be subjected to the modification reaction, the type of unsaturated carboxylic acid component as the modifier, and the modification conditions, and one type may be used alone, or two or more types may be used in combination. The radical generator can also be used by dissolving it in an organic solvent or the like.

[0067] The modification reaction carried out to obtain the modified ethylene copolymer of the present invention can be carried out by various known reaction methods such as a melt-kneading reaction method, a solution reaction method, a suspension dispersion reaction method, etc., but the melt-kneading reaction method is usually preferred.

[0068] In the case of the melt-kneading reaction method, the components are mixed uniformly at a predetermined ratio and then melt-kneaded. For mixing, a Henschel mixer, ribbon blender, V-type blender, or the like is used, and for melt-kneading, a Banbury mixer, kneader, roll, or multi-screw kneading extruder such as a single-screw or twin-screw kneading extruder, or the like is used.

[0069] The melt-kneading is carried out at a temperature of usually 100°C or higher, preferably 120°C or higher, more preferably 150°C or higher, and usually 300°C or lower, preferably 280°C or lower, more preferably 250°C or lower, so as to prevent thermal degradation of the polymer.

[0070] The amount of the unsaturated carboxylic acid component used as a modifier is usually 0.01 part by mass or more, preferably 0.05 part by mass or more, more preferably 0.1 part by mass or more, and usually 30 parts by mass or less, preferably 5 parts by mass or less, more preferably 4 parts by mass or less, relative to 100 parts by mass of the ethylene copolymer as the raw polymer. By setting the amount of the unsaturated carboxylic acid component within the above range, it is economical and sufficient modification can be achieved.

[0071] The amount of radical generator blended is usually 0.001 part by mass or more, preferably 0.005 part by mass or more, more preferably 0.01 part by mass or more, and usually 1 part by mass or less, preferably 0.5 part by mass or less, more preferably 0.1 part by mass or less, per 100 parts by mass of the ethylene copolymer as the raw polymer. By setting the amount of radical generator blended to be equal to or greater than the above-mentioned lower limit, sufficient modification can be achieved. By setting the amount of radical generator blended to be equal to or less than the above-mentioned upper limit, the increase in molecular weight (increase in viscosity) during modification of the ethylene copolymer can be kept within a desired range, and the desired modified ethylene copolymer tends to be more easily obtained.

[0072] In the modification reaction, a graft polymerization reaction in which an unsaturated carboxylic acid component is added to the ethylene copolymer mainly occurs, but a crosslinking reaction also occurs, and this crosslinking tends to increase the molecular weight of the resulting modified product and increase the melt viscosity. Therefore, if the amount of radical generator used is too large, the graft polymerization reaction is likely to occur, but at the same time, the crosslinking reaction that leads to such an increase in melt viscosity is also likely to occur, which is not preferable.

[0073] <Grafting rate> The graft ratio of the modified ethylene copolymer that is the acid-modified polyolefin (d) is preferably 0.1 to 1.0 mass%, more preferably 0.6 to 1.0 mass%, and even more preferably 0.8 to 1.0 mass%. When the graft ratio is equal to or higher than the lower limit, good recyclability can be obtained. However, if the graft ratio is too high, there will be a lot of burning, which will have a negative effect on the appearance of the recycled film. Therefore, the graft ratio of the modified ethylene copolymer that is the acid-modified polyolefin (d) is preferably equal to or lower than the upper limit.

[0074] The acid-modified polyolefin (d) may be used alone or in combination of two or more kinds having different physical properties.

[0075] [Mixing ratio] The polymer composition of the present invention contains 0.1 to 20 parts by mass of the polar polymer (b) and 0.1 to 25 parts by mass of the acid-modified polyolefin (d) based on 100 parts by mass of the polyolefin polymer (a).

[0076] If the polar polymer (b) is less than 0.1 parts by mass, the barrier properties due to the inclusion of the polar polymer (b) cannot be sufficiently obtained. On the other hand, if the polar polymer (b) is more than 20 parts by mass, the impact resistance of the resulting molded article tends to decrease. The polar polymer (b) is preferably contained in an amount of 1 to 15 parts by mass, particularly preferably 5 to 10 parts by mass, per 100 parts by mass of the polyolefin polymer (a).

[0077] If the amount of the acid-modified polyolefin (d) is less than 0.1 parts by mass, the effect of finely dispersing the polar polymer (b) in the polymer composition cannot be sufficiently obtained, and the recycled composition will not be able to sufficiently prevent a decrease in transparency or the generation of foreign matter during the extrusion process. On the other hand, if the amount of the acid-modified polyolefin (d) is more than 25 parts by mass, the generation of foreign matter during the extrusion process will not be sufficiently prevented. The acid-modified polyolefin (d) is preferably contained in an amount of 0.5 to 15 parts by mass, particularly preferably 1 to 10 parts by mass, per 100 parts by mass of the polyolefin polymer (a).

[0078] When the polymer composition of the present invention contains an acid-modified polyolefin (c), the content of the acid-modified polyolefin (c) is preferably 0.1 to 20 parts by mass, particularly 1 to 18 parts by mass, and particularly 5 to 15 parts by mass, per 100 parts by mass of the polyolefin copolymer (a). When the content of the acid-modified polyolefin (c) is within the above range, the dispersibility of the polar polymer (b) in the polymer composition is improved, and the impact resistance of the resulting molded article is improved.

[0079] [Other ingredients] The polymer composition of the present invention may contain other polymers than the polyolefin polymer (a), polar polymer (b), acid-modified polyolefin (c), and acid-modified polyolefin (d), as well as optional additives (hereinafter referred to as "other components"), depending on the purpose, within the scope of not significantly impairing the effects of the present invention. Only one type of other component may be used, or two or more types may be used in any combination and ratio.

[0080] Examples of additives include antioxidants, ultraviolet absorbers, plasticizers, lubricants, fillers, and antistatic agents. The total content of these additives in the polymer composition of the present invention is usually 50% by mass or less, preferably 20% by mass or less, and more preferably 10% by mass or less.

[0081] [Method of producing polymer composition] The method for mixing the components to obtain the polymer composition of the present invention is not particularly limited, and examples thereof include a method in which the polyolefin polymer (a), the polar polymer (b), and the acid-modified polyolefin (d), the acid-modified polyolefin (c) used as needed, and other components are dry-blended and melt-kneaded all at once; a method in which the polyolefin polymer (a), the polar polymer (b), and the acid-modified polyolefin (d), the acid-modified polyolefin (c) used as needed, and some of the other components are melt-kneaded in advance, and then other components are blended and melt-kneaded; and a method in which a multilayer structure containing the polyolefin polymer (a), the polar polymer (b), and the acid-modified polyolefin (d), the acid-modified polyolefin (c) used as needed, and some or all of the other components is blended and melt-kneaded with other components.

[0082] A preferred method for producing the polymer composition of the present invention is to melt-knead a recycled multilayer packaging material containing a polyolefin polymer (a) layer and a polar polymer (b) layer, or a recycled multilayer packaging material containing a polyolefin polymer (a) layer, a polar polymer (b) layer, and an acid-modified polyolefin (c) layer, with a compatibilizer containing an acid-modified polyolefin (d). Here, the recycled multilayer packaging material refers to scrap such as flash generated during the production of a molded product made of the multilayer packaging material, or rejected products during molding. An additive blended when melt-kneading such recycled materials is referred to as a compatibilizer, and a compatibilizer containing an acid-modified polyolefin (d) is used here. The content of the acid-modified polyolefin (d) in the compatibilizer is preferably 5 to 100% by mass. The content of the acid-modified polyolefin (d) is more preferably 10% by mass or more, even more preferably 20% by mass or more, and particularly preferably 50% by mass or more.

[0083] A specific example of a method for melt-kneading is to mix the components uniformly at a predetermined blending ratio using a Henschel mixer, ribbon blender, V-type blender, or the like, and then knead them using a multi-screw kneading extruder, for example, a twin-screw kneading extruder, TEX25, manufactured by The Japan Steel Works.

[0084] The temperature for melt-kneading each component is usually 100 to 300°C, preferably 120 to 280°C, more preferably 150 to 250°C, similar to the temperature during the graft modification of the acid-modified polyolefin (d) described above.

[0085] [Molded product] The molded article of the present invention is obtained by molding the polymer composition of the present invention.

[0086] Examples of shapes of the molded article of the present invention include films, sheets, tapes, cups, trays, tubes, bottles, pipes, filaments, extruded products with irregular cross sections, and various irregularly shaped articles.

[0087] There is no particular limitation on the method for molding the polymer composition of the present invention, and any molding method applicable to general polymer compositions can be used. For example, extrusion molding, blow molding, injection molding, thermoforming, etc. can be mentioned.

[0088] Furthermore, in molding, a heat stretching treatment is often performed to improve the physical properties of the molded product or to mold it into a desired container shape. Here, heat stretching refers to the process of uniformly molding a thermally uniformly heated film, sheet, or parison-shaped molded product into a cup, tray, tube, bottle, or film shape using a chuck, plug, vacuum, compressed air, blowing, or the like. Examples of the stretching method include roll stretching, tenter stretching, tubular stretching, stretch-blow method, vacuum forming, compressed air forming, and vacuum-compressed air forming. The stretching may be either uniaxial or biaxial, and in the case of biaxial stretching, either simultaneous biaxial stretching or sequential biaxial stretching can be used. The stretching temperature is usually 60 to 170°C, and preferably 80 to 160°C.

[0089] [Multilayer packaging material] The multilayer packaging material of the present invention has a layer containing the polymer composition of the present invention. The multilayer packaging material of the present invention can be produced by the method for producing the multilayer packaging material of the present invention, which includes a step of melt-molding a polyolefin polymer (a), a polar polymer (b), and an acid-modified polyolefin (d), and if necessary, further an acid-modified polyolefin (c). That is, the polymer composition of the present invention can be used as at least one layer (regrind layer) of such a multi-layer packaging material. The multi-layer packaging material containing a regrind layer will be described below.

[0090] [Multilayer packaging material containing regrind layer] A regrind layer-containing multilayer packaging material is sufficient if it has at least one regrind layer (sometimes referred to as a "Reg layer") made of the polymer composition of the present invention within its laminate. Generally, a multilayer packaging material is preferred that contains, in addition to the regrind layer, a polyolefin polymer layer (sometimes referred to as a "PO layer"), an EVOH layer and / or a polyamide polymer layer (sometimes referred to as a "PA layer"), and, if necessary, an acid-modified polyolefin (c) layer.

[0091] Specific examples of the layer structure of the Reg layer-containing multilayer packaging material include the following. PO layer / Reg layer / acid-modified polyolefin (c) layer / EVOH layer or PA layer, PO layer / Reg layer / acid-modified polyolefin (c) layer / EVOH layer or PA layer / acid-modified polyolefin (c) layer / PO layer, PO layer / Registered layer / acid-modified polyolefin (c) layer / EVOH layer or PA layer / acid-modified polyolefin (c) layer / Registered layer / PO layer, Reg layer / EVOH layer or PA layer, Reg layer / acid-modified polyolefin (c) layer / EVOH layer or PA layer, Reg layer / acid-modified polyolefin (c) layer / EVOH layer or PA layer / acid-modified polyolefin (c) layer / EVOH layer or PA layer, Reg layer / acid-modified polyolefin (c) layer / EVOH layer or PA layer / acid-modified polyolefin (c) layer / PO layer, Reg layer / acid-modified polyolefin (c) layer / EVOH layer or PA layer / acid-modified polyolefin (c) layer / Reg layer / PO layer, PO layer / acid-modified polyolefin (c) layer / EVOH layer or PA layer / Reg layer / EVOH layer or PA layer / acid-modified polyolefin (c) layer / PO layer.

[0092] Examples of the layer structure of a Reg layer-containing multilayer packaging material that includes an EVOH layer and a PA layer include the following. PO layer / Registered layer / acid-modified polyolefin (c) layer / PA layer / EVOH layer / PA layer / acid-modified polyolefin (c) layer / Registered layer / PO layer, PO layer / Reg layer / acid-modified polyolefin (c) layer / PA layer / EVOH layer / PA layer / acid-modified polyolefin (c) layer / PO layer, PO layer / acid-modified polyolefin (c) layer / PA layer / EVOH layer / PA layer / acid-modified polyolefin (c) layer / Reg layer / PO layer, PA layer / acid-modified polyolefin (c) layer / PO layer / Registered layer / PO layer / acid-modified polyolefin (c) layer / PA layer / EVOH layer / acid-modified polyolefin (c) layer / Registered layer / PO layer, PA layer / acid-modified polyolefin (c) layer / PO layer / Reg layer / PO layer / acid-modified polyolefin (c) layer / PA layer / EVOH layer / acid-modified polyolefin (c) layer / PO layer, PA layer / acid-modified polyolefin (c) layer / PO layer / acid-modified polyolefin (c) layer / PA layer / EVOH layer / acid-modified polyolefin (c) layer / Reg layer / PO layer, PA layer / acid-modified polyolefin (c) layer / Reg layer / acid-modified polyolefin (c) layer / PA layer / EVOH layer / acid-modified polyolefin (c) layer / PO layer, PA layer / acid-modified polyolefin (c) layer / PO layer / Reg layer / PO layer / acid-modified polyolefin (c) layer / EVOH layer / acid-modified polyolefin (c) layer / PO layer, PA layer / acid-modified polyolefin (c) layer / PO layer / acid-modified polyolefin (c) layer / EVOH layer / acid-modified polyolefin (c) layer / Reg layer / PO layer, PA layer / acid-modified polyolefin (c) layer / Reg layer / acid-modified polyolefin (c) layer / EVOH layer / acid-modified polyolefin (c) layer / PO layer.

[0093] The thickness of each layer of the regrind layer-containing multilayer packaging material cannot be generalized depending on the layer structure, type of polyolefin polymer, intended use, container form, required physical properties, etc., but the thickness of the regrind layer is usually 5 to 5,000 μm, preferably 30 to 1,000 μm. The thickness of the EVOH layer is usually 5 to 500 μm, preferably 10 to 200 μm. The thickness of the polyolefin polymer layer is usually 5 to 5,000 μm, preferably 30 to 1,000 μm. When an acid-modified polyolefin (c) layer is present, the thickness of the acid-modified polyolefin (c) layer is usually 5 to 400 μm, preferably 10 to 150 μm.

[0094] The thickness ratio of the regrind layer to the polyolefin polymer layer is usually 1 / 5 to 10 / 1, and preferably 1 / 2 to 5 / 1. The thickness ratio of the regrind layer to the EVOH layer is usually 1 / 1 to 100 / 1, and preferably 5 / 1 to 20 / 1.

[0095] [Manufacturing method for regrind layer-containing multi-layer packaging material] The regrind layer-containing multilayer packaging material can be produced, for example, by molding the same type of resin as the recycled multilayer packaging material using the same method. In this case, there are no particular limitations on the molding method for the polymer composition of the present invention, and any molding method applicable to general polymer compositions can be used. Specifically, the recycled laminate can be produced using the polyolefin polymer used in the polyolefin polymer layer, the EVOH used in the EVOH layer, and the acid-modified polyolefin (c) used in the acid-modified polyolefin (c) layer, as exemplified in the recycled laminate, by a lamination method such as extrusion molding, blow molding, injection molding, thermoforming, etc., especially coextrusion molding and coinjection molding, in particular coextrusion molding.

[0096] The multilayer packaging material obtained in this manner, whether recycled or re-recycled, is useful as a variety of packaging material containers for general foods, seasonings such as mayonnaise and dressings, fermented foods such as miso, oily foods such as salad oil, beverages, cosmetics, pharmaceuticals, etc. [Example]

[0097] Specific embodiments of the present invention will be described in more detail below using examples, but the present invention is not limited to the following examples as long as the gist of the invention is not exceeded. Note that the values ​​of various production conditions and evaluation results in the following examples represent preferred upper or lower limit values ​​in the embodiments of the present invention, and preferred ranges may be defined by a combination of the above-mentioned upper or lower limit values ​​and the values ​​in the following examples or values ​​between the examples.

[0098] In the following Examples and Comparative Examples, the raw materials used to prepare the modified copolymers and regrind compositions are as follows:

[0099] [Modified copolymer raw material] <Ethylene-butene copolymer> e-1: TAFMER (registered trademark) A35070S manufactured by Mitsui Chemicals, Inc. (MFR (190°C, load 2.16 kg): 35 g / 10 min, density: 0.870 g / cm 3 ) e-2: TAFMER (registered trademark) A4085S manufactured by Mitsui Chemicals, Inc. (MFR (190°C, load 2.16 kg): 3.6 g / 10 min, density: 0.885 g / cm 3 ) e-3: TAFMER (registered trademark) A20085S manufactured by Mitsui Chemicals, Inc. (MFR (190°C, load 2.16 kg): 18 g / 10 min, density: 0.885 g / cm 3 ) e-4: TAFMER (registered trademark) A70050S manufactured by Mitsui Chemicals, Inc. (MFR (190°C, load 2.16 kg): 70 g / 10 min, density: 0.893 g / cm 3 )

[0100] <Radical generator> Organic peroxide: Perhexa 25B manufactured by Nippon Oil & Fats Co., Ltd.

[0101] <Unsaturated carboxylic acid component> Maleic anhydride (commercially available)

[0102] <Ethylene-octene copolymer> o-1: Dow AFFINITY® GA1900 (MFR (190°C, load 2.16 kg): 1000 g / 10 min, density: 0.870 g / cm 3 )

[0103] [Regrind composition materials] <Polyolefin polymer (a)> PE: Novatec® UF230 polyethylene manufactured by Japan Polyethylene Corporation (MFR (190°C, load 2.16 kg): 1 g / 10 min, density: 0.921 g / cm 3 ) PP: Polypropylene manufactured by Japan Polypropylene Corporation, Novatec® EA7AD (MFR (210°C, load 2.16 kg): 1.4 g / 10 min, density: 0.9 g / cm 3 )

[0104] <EVOH(b1)> ·EVOH (MFR (210℃, load 2.16kg): 3.8g / 10 minutes, density: 1.19g / cm 3 ethylene unit content: 32 mol%, saponification degree: 99.9 mol%)

[0105] <Polyamide polymer (b2)> Ny: Polyamide polymer 1022 manufactured by DSM (MFR (210°C, load 2.16 kg): 6.6 g / 10 min, density: 1.13 g / cm 3 )

[0106] <Acid-modified polyolefin (c)> c-1: Maleic anhydride-modified polyethylene Modic (registered trademark) M512 manufactured by Mitsubishi Chemical Corporation (MFR (190°C, load 2.16 kg): 1.0 g / 10 min, density: 0.900 g / cm 3 ) c-2: Maleic anhydride-modified polypropylene P604V manufactured by Mitsubishi Chemical Corporation (MFR (190°C, load 2.16 kg): 1.0 g / 10 min, MFR (230°C, load 2.16 kg): 3.2 g / 10 min, density: 0.9 g / cm3) 3 )

[0107] [Preparation of modified copolymer] <Synthesis Example 1> 100 parts by mass of component (e-1), 0.03 parts by mass of a radical generator, and 0.15 parts by mass of an unsaturated carboxylic acid component were dry-blended and mixed, and the mixture was melt-kneaded using a twin-screw extruder (The Japan Steel Works, Ltd., TEX25αIII, D=25 mmφ, L / D=52.5) ​​at a set temperature of 230°C, a screw rotation speed of 400 rpm, and an extrusion rate of 20 kg / h. Pellet-shaped maleic anhydride-modified ethylene-butene copolymer (d-1) was obtained by strand cutting. The MFR (190°C, 2.16 kg), density, and graft ratio of the resulting modified ethylene-butene copolymer (d-1) were measured using the methods described above. The measurement results are shown in Table 1.

[0108] <Synthesis Examples 2 to 8> Modified copolymers (d-2) to (d-8) were obtained in the same manner as in Synthesis Example 1, except that the blending compositions were changed as shown in Table 1. Using the resulting modified copolymers, the MFR (190°C, 2.16 kg), density, and graft ratio were measured in the same manner as in Synthesis Example 1. The measurement results are shown in Table 1.

[0109] [Table 1]

[0110] [Preparation and Evaluation of Polyethylene Regrind Compositions] Example 1 A dry blend of 77 parts by weight of polyethylene Novatec® UF230 (manufactured by Japan Polyethylene Corporation), 10 parts by weight of EVOH Soarnol® DC3203RB (manufactured by Mitsubishi Chemical Corporation), and 10 parts by weight of Modic® M512 (manufactured by Mitsubishi Chemical Corporation) with 3 parts by weight of the modified ethylene-butene copolymer (d-1) from Synthesis Example 1 as a compatibilizer was performed. The mixture was melt-kneaded using a twin-screw extruder (TEX25αIII, manufactured by The Japan Steel Works, Ltd., D=25 mmφ, L / D=52.5) ​​at a set temperature of 210°C, a screw rotation speed of 400 rpm, and an extrusion rate of 20 kg / h. The pellets were then strand-cut to obtain a regrind composition in the form of pellets. The resulting regrind composition was evaluated for the following criteria (1) to (5). The evaluation results are shown in Table 2A.

[0111] <Examples 2 to 8, 10, Comparative Examples 1 to 7> Regrind compositions were obtained in the same manner as in Example 1, except that the blending compositions were changed as shown in Tables 2A and 2B. The resulting regrind compositions were evaluated for the following items (1) to (5). The evaluation results are shown in Tables 2A and 2B.

[0112] Example 9 A dry blend of 77 parts by weight of polyethylene Novatec® UF230 (manufactured by Japan Polyethylene Corporation), 10 parts by weight of Ny 1022 (manufactured by DSM), and 10 parts by weight of Modic® M512 (manufactured by Mitsubishi Chemical Corporation) with 3 parts by weight of the modified ethylene-butene copolymer (d-3) from Synthesis Example 3 as a compatibilizer was performed. The mixture was melt-kneaded using a twin-screw extruder (manufactured by The Japan Steel Works, Ltd., TEX25αIII, D=25 mmφ, L / D=52.5) ​​at a set temperature of 220°C, a screw speed of 400 rpm, and an extrusion rate of 20 kg / h. The pellets were then strand-cut to obtain a regrind composition in the form of pellets. The resulting regrind composition was evaluated for the following criteria (1) to (5). The evaluation results are shown in Table 2A.

[0113] [Evaluation method] (1) Transparency Using a single-layer T-die film molding machine (extruder: 50 mmφ, lip opening: 0.3 mm) manufactured by GSI Creos Co., Ltd., a film with a thickness of 0.1 mm was produced at a set temperature of 200°C and a screw rotation speed of 20 rpm. The films obtained were compared visually, with highly transparent films being rated as ○, slightly opaque films as △, and opaque films as ×.

[0114] (2) Internal haze Using the 0.1 mm thick film prepared above, the internal haze was measured using a haze meter (n = 3) and the average value was calculated. The internal haze is an index for evaluating the dispersibility of EVOH or Ny in the polymer composition; the smaller the internal haze value, the more finely dispersed the EVOH or Ny is and the better the appearance. In this evaluation, an internal haze value of 20% or less can be evaluated as indicating good dispersibility of EVOH or Ny.

[0115] (3) Tensile breaking strength Using the 0.1 mm thick film prepared above, the tensile breaking strength was measured (n=3) according to a method in accordance with JIS K7161, and the average value was calculated. A tensile breaking strength of 25 MPa or more can be said to have good mechanical properties.

[0116] (4) Amount of foreign matter attached The regrind composition was extruded using a twin-screw extruder (manufactured by The Japan Steel Works, Ltd., TEX25αIII, D=25mmφ, L / D=52.5) ​​at a set temperature of 210°C, a screw rotation speed of 400 rpm, and an extrusion rate of 20 kg / h. The amount of low molecular weight pyrolysis products precipitated at the die head was visually confirmed. After one hour of extrusion, the amount of foreign matter adhering to the die head was checked, and the amount was marked with ◎ if there was no adhesion, ○ if there was a small amount of adhesion, △ if there was a little amount of adhesion, and × if there was a large amount of adhesion.

[0117] (5) Recyclability The regrind composition obtained above was melt-kneaded again in a twin-screw extruder under the conditions described in the preparation of the regrind composition. The resulting recycled composition was evaluated for transparency, internal haze, tensile strength at break, and amount of foreign matter adhesion as described in (1) to (4) above, and compared with the properties of the regrind composition obtained in the first melt-kneading, with the results being rated as ◯ if the properties were equivalent, △ if a slight deterioration in properties was observed, and × if a deterioration in properties was observed.

[0118] [Table 2A]

[0119] [Table 2B]

[0120] [Preparation and Evaluation of Polypropylene Regrind Compositions] Example 11 77 parts by weight of polypropylene Novatec® EA7AD manufactured by Japan Polyethylene Corporation, 10 parts by weight of EVOH® DC3203RB manufactured by Mitsubishi Chemical Corporation, and 10 parts by weight of Modic® P604V manufactured by Mitsubishi Chemical Corporation were dry-blended with 3 parts by weight of the modified ethylene-butene copolymer (d-1) from Synthesis Example 1 as a compatibilizer. The mixture was melt-kneaded using a twin-screw extruder (TEX25αIII manufactured by The Japan Steel Works, Ltd., D=25 mmφ, L / D=52.5) ​​at a set temperature of 210°C, a screw rotation speed of 400 rpm, and an extrusion rate of 20 kg / h. The pellets were then strand-cut to obtain a regrind composition in the form of pellets. The resulting regrind composition was evaluated according to the above criteria (1) to (5). The evaluation results are shown in Table 3A.

[0121] <Examples 12 to 18, Comparative Examples 8 to 12> A regrind composition was obtained in the same manner as in Example 11, except that the blending composition was changed as shown in Table 3. The obtained regrind composition was evaluated according to the above items (1) to (5). The evaluation results are shown in Table 3.

[0122] [Table 3]

[0123] [Consideration] <Polyethylene-based regrind composition> As shown in Table 2A, Examples 1 to 10, which used the polymer compositions of the present invention containing the modified ethylene-butene copolymers (d-1) to (d-4) as compatibilizers, were able to eliminate or reduce the amount of foreign matter adhesion without impairing transparency. Furthermore, they also achieved excellent results in terms of internal haze, mechanical properties, and recyclability. In contrast, Comparative Example 1, which used a modified ethylene-butene copolymer (d-5) with an MFR of 2 g / 10 min, Comparative Example 2, which used a modified ethylene-butene copolymer (d-6) with an MFR of 13 g / 10 min, and Comparative Example 3, which used a modified ethylene-butene copolymer (d-7) with an MFR of 59 g / 10 min, were slightly opaque and had a large amount of foreign matter attached, indicating that they were less effective as compatibilizers. Comparative Example 4, which used a modified ethylene-octene copolymer (d-8) with an MFR of 640 g / 10 min, had high transparency but a somewhat large amount of foreign matter attached, and in the evaluation of recyclability, the internal haze significantly deteriorated and the tensile strength was also reduced, resulting in poor recyclability. Comparative Examples 5 and 7 show examples in which no compatibilizer was used, and although there was no or only a small amount of foreign matter attached, the film was opaque or slightly opaque and was poor in recyclability. Furthermore, Comparative Example 6 shows an example in which the content of the modified ethylene-butene copolymer (d-3) was high, and the recyclability was poor.

[0124] <Polypropylene-based regrind composition> As shown in Table 3, Examples 11 to 18, which used the polymer compositions of the present invention containing the modified ethylene-butene copolymers (d-1) to (d-3) as compatibilizers, showed excellent recyclability, zero or no foreign matter adhesion, and excellent internal haze and mechanical properties, without impairing transparency. In contrast, the recyclability was poor in Comparative Example 8, which used a modified ethylene-butene copolymer (d-5) with an MFR of 2 g / 10 min, and Comparative Example 9, which used a modified ethylene-butene copolymer (d-7) with an MFR of 59 g / 10 min. Comparative Example 10, which used a modified ethylene-octene copolymer (d-8) with an MFR of 640 g / 10 min, showed poor recyclability. Comparative Example 11 shows an example in which no compatibilizer was used, and although the amount of foreign matter attached was small, the film was opaque and the recyclability was poor. Furthermore, Comparative Example 12 shows an example in which the content of the modified ethylene-butene copolymer (d-3) was high, and as a result, the amount of foreign matter adhesion was high.< / mfr>

Claims

1. A polymer composition comprising, per 100 parts by mass of a polyolefin polymer (a), 0.1 to 20 parts by mass of at least one polar polymer (b) selected from an ethylene-vinyl alcohol copolymer (b1) and a polyamide polymer (b2), and 0.1 to 25 parts by mass of an acid-modified polyolefin (d), The acid-modified polyolefin (d) is a modified ethylene copolymer obtained by modifying a copolymer of an ethylene monomer and one or more α-olefin monomers having 4 to 8 carbon atoms with an unsaturated carboxylic acid and / or an anhydride thereof, and the modified ethylene copolymer has a melt flow rate (MFR: 190°C, 2.16 kg) of 15 to 39 g / 10 min.

2. The polymer composition according to claim 1, further comprising an acid-modified polyolefin (c) having a melt flow rate (MFR: 190°C, 2.16 kg) of 0.01 g / 10 min or more and less than 15 g / 10 min.

3. 3. The polymer composition according to claim 2, wherein the content of the acid-modified polyolefin (c) is 0.1 to 20 parts by mass per 100 parts by mass of the polyolefin polymer (a).

4. The density of the acid-modified polyolefin (d) is 0.855 to 0.895 g / cm ３ 2. The polymer composition of claim 1, wherein

5. The polymer composition according to claim 1, wherein the grafting rate of the acid-modified polyolefin (d) is 0.1 to 1.0 mass%.

6. The polymer composition according to claim 1, wherein the acid-modified polyolefin (d) is a modified ethylene-butene copolymer.

7. The polymer composition according to claim 1, wherein the polyolefin polymer (a) is polyethylene.

8. 2. The polymer composition according to claim 1, wherein the polar polymer (b) is an ethylene-vinyl alcohol copolymer (b1) having an ethylene unit content of 20 mol% or more and less than 50 mol%.

9. A molded article obtained by molding the polymer composition according to any one of claims 1 to 8.

10. A multilayer packaging material having a layer comprising the polymer composition according to any one of claims 1 to 8.

11. 9. A method for producing the polymer composition according to claim 1, comprising a step of melt-kneading the polyolefin polymer (a), at least one polar polymer (b) selected from the ethylene-vinyl alcohol copolymer (b1) and the polyamide polymer (b2), and the acid-modified polyolefin (d).

12. 11. A method for producing a multilayer packaging material according to claim 10, comprising a step of melt-molding the polyolefin polymer (a), at least one polar polymer (b) selected from the ethylene-vinyl alcohol copolymer (b1) and the polyamide polymer (b2), and the acid-modified polyolefin (d).

Images