Resin composition and film

Abstract

To provide a resin composition suppressed in discoloration caused by a thermal history or the like in a production process or the like while maintaining moderately low glossiness and good adhesiveness (peel strength) and antibacterial properties, and to provide a film containing the resin composition.SOLUTION: The resin composition includes an ethylene-vinyl alcohol copolymer (A), an acid-modified polyolefin (B), an inorganic antibacterial agent (C), a heavy metal deactivator (D), and at least one selected from the group consisting of an alkali metal salt and an alkaline earth metal salt, wherein the total content of the alkali metal salt and the alkaline earth metal salt is 6 μ mol / g or more in terms of metal.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition and a film that can be suitably used as materials for wallpaper and the like. [Background technology]

[0002] Conventionally, laminates primarily composed of inexpensive and durable polyvinyl chloride resin layers have been used as interior materials. However, wallpapers primarily composed of polyvinyl chloride resin layers and decorative panels (hereinafter sometimes collectively referred to as wallpapers) used for ceilings, walls, and floors in homes, hospitals, clinics, restaurants, factories, ships, trains, and automobiles are easily contaminated by cigarette smoke, fingerprints, graffiti, and various food colorings. Furthermore, the plasticizers added to polyvinyl chloride resins bleed out onto the wallpaper surface, making this bleed-out plasticizer more susceptible to dust adhesion, further increasing the susceptibility of wallpapers primarily composed of polyvinyl chloride resin layers to soiling. Another problem is the lack of bacterial growth inhibitory properties (antibacterial properties) needed to prevent hospital-acquired infections, which are a major concern in hospitals and clinics.

[0003] To solve these problems, a composition has been proposed that contains 90 to 99.9 mass% of a saponified ethylene-vinyl ester copolymer with an ethylene content of 20 to 65 mol% and a degree of saponification of the vinyl ester component of 90 mol% or more, and 10 to 0.1 mass% of an inorganic oxoacid salt containing an antibacterial metal ion, as well as wallpaper or decorative laminates that have a layer of the composition on at least one side of a polyvinyl chloride resin layer containing a plasticizer. Furthermore, Patent Document 1 states that a composition with excellent matte finish can be obtained by blending carboxylic acid-modified polyethylene. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 06-263933 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the antibacterial resin composition of Patent Document 1 may have insufficient adhesiveness (peel strength) to the substrate layer that constitutes the wallpaper, and further improvement in adhesiveness, etc. is desired.

[0006] Therefore, the inventors have experimentally produced a resin composition containing a specific amount of alkali metal salt and / or alkaline earth metal salt in order to improve the adhesiveness (peel strength) of the above-mentioned antibacterial resin composition. However, although an antibacterial resin composition with improved adhesiveness (peel strength) was obtained, it was found that a new problem arose in that the composition was significantly discolored due to the thermal history of the manufacturing process, etc.

[0007] Therefore, an object of the present invention is to provide a resin composition and a film containing the resin composition that maintain a moderately low gloss level, good adhesion (peel strength) and antibacterial properties, while suppressing discoloration due to thermal history during the manufacturing process, etc. [Means for solving the problem]

[0008] The above challenges are [1] A resin composition comprising an ethylene-vinyl alcohol copolymer (A), an acid-modified polyolefin (B), an inorganic antibacterial agent (C), a heavy metal deactivator (D), and at least one selected from the group consisting of an alkali metal salt and an alkaline earth metal salt, wherein the total content of the alkali metal salt and the alkaline earth metal salt is 6 μmol / g or more in terms of metal; [2] The resin composition according to [1], wherein the content of the acid-modified polyolefin (B) per 100 parts by mass of the ethylene-vinyl alcohol copolymer (A) is 1 to 100 parts by mass; [3] The resin composition according to [1] or [2], wherein the content of the inorganic antibacterial agent (C) is 0.1 to 5 parts by mass per 100 parts by mass of the ethylene-vinyl alcohol copolymer (A); [4] The resin composition according to any one of [1] to [3], wherein the content of the heavy metal deactivator (D) per 100 parts by mass of the ethylene-vinyl alcohol copolymer (A) is 0.05 to 5 parts by mass; [5] The resin composition according to any one of [1] to [4], wherein the heavy metal deactivator (D) is at least one selected from the group consisting of oxalic acid derivatives, salicylic acid derivatives, hydrazide derivatives, triazole derivatives, and imidazole derivatives; [6] The resin composition according to any one of [1] to [5], wherein the heavy metal deactivator (D) is a salicylic acid derivative; [7] The resin composition according to any one of [1] to [6], wherein the inorganic antibacterial agent (C) is an antibacterial agent containing a heavy metal; [8] The object is achieved by providing a film containing the resin composition according to any one of [1] to [7]. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a resin composition and a film made of the resin composition that maintain a moderately low gloss level, good adhesion (peel strength) and antibacterial properties while suppressing discoloration due to thermal history during the manufacturing process, etc. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described. In this specification, a numerical range stated using "to" means that the numerical values ​​stated before and after "to" are included.

[0011] The resin composition of the present invention contains an ethylene-vinyl alcohol copolymer (A), an acid-modified polyolefin (B), an inorganic antibacterial agent (C), a heavy metal deactivator (D), and at least one selected from the group consisting of an alkali metal salt and an alkaline earth metal salt, and the total content of the alkali metal salt and the alkaline earth metal salt is 6 μmol / g or more in terms of metal. The resin composition of the present invention maintains an appropriately low gloss, good adhesion (peel strength), and antibacterial properties, while suppressing discoloration due to heat history during the manufacturing process, etc.

[0012] According to the inventors' investigations, even when a resin composition contains an ethylene-vinyl alcohol copolymer (A) (hereinafter sometimes referred to as EVOH (A)) and an inorganic antibacterial agent (C), discoloration due to thermal history during the manufacturing process is unlikely to occur if the resin composition does not contain an acid-modified polyolefin (B) and the total content of alkali metal salts and alkaline earth metal salts is less than 6 μmol / g. In other words, discoloration due to thermal history during the manufacturing process is a problem that only arises when the resin composition contains an ethylene-vinyl alcohol copolymer (A), an acid-modified polyolefin (B), and an inorganic antibacterial agent (C) and the total content of alkali metal salts and alkaline earth metal salts is 6 μmol / g or more, and this problem is solved by the embodiments of the present disclosure. While the reason for this is unclear, one presumed reason is explained below, taking the case where the inorganic antibacterial agent (C) is silver zeolite as an example. The acid-modified polyolefin (B) promotes the release of silver (monovalent) from the carrier. Silver (monovalent) is stable when supported, but becomes unstable when released and is easily reduced to silver (zerovalent). As a result, EVOH (A) is oxidized by silver (monovalent), resulting in the elimination of hydroxyl groups in EVOH (A) and the formation of conjugated bonds. This conjugated bond is one of the causes of discoloration of the resin composition. When the total content of alkali metal salts and alkaline earth metal salts is 6 μmol / g or more, the ring structures that may be partially contained in the acid-modified polyolefin (B) are opened, increasing the carboxyl group content. This significantly accelerates the release of silver (monovalent) from the support, which is thought to be the cause of the discoloration of the resin composition.

[0013] The ethylene content of the ethylene-vinyl alcohol copolymer (A) (the content of ethylene units relative to all monomer units) is preferably 20 to 65 mol%, more preferably 25 to 60 mol%, and in some cases, even more preferably 30 to 50 mol%. When the ethylene content is 20 mol% or higher, water resistance tends to be excellent. When the ethylene content is 65 mol% or lower, oil resistance, resistance to penetration of oily contaminants, and stain resistance tend to be excellent. The saponification degree of the vinyl ester component of EVOH (A) is preferably 90 mol% or higher, more preferably 95 mol% or higher, and in some cases, 98 mol% or higher or 99 mol% or higher are even more preferable. When the saponification degree of the vinyl ester component is 90 mol% or higher, oil resistance, resistance to penetration of oily contaminants, and stain resistance tend to be excellent. The saponification degree refers to the ratio of the number of vinyl alcohol units to the total number of vinyl alcohol units and vinyl ester units in EVOH (A). The ethylene content and saponification degree of EVOH (A) can be determined by nuclear magnetic resonance (NMR) spectroscopy.

[0014] The method for producing EVOH (A) is not particularly limited, and examples include a method of copolymerizing a vinyl ester and ethylene and saponifying the resulting copolymer. From an economical standpoint, vinyl acetate is preferred as the vinyl ester. EVOH (A) may contain other monomer units in addition to ethylene units, vinyl ester units, and vinyl alcohol units, as long as the object of the present invention is not impaired. The content of the other monomer units is preferably 10 mol % or less, more preferably 5 mol % or less, and even more preferably 1 mol % or less, based on the total monomer units of EVOH (A), and may be 0.1 mol % or less.

[0015] The melt flow rate (MFR) of EVOH (A) (190°C, under a load of 2160 g) is not particularly limited, but is preferably 0.3 to 150 g / 10 min, more preferably 0.5 to 120 g / 10 min, even more preferably 0.8 to 90 g / 10 min, and particularly preferably 1 to 60 g / 10 min. However, for EVOH (A) with a melting point near or exceeding 190°C, the MFR is measured under a load of 2160 g at multiple temperatures equal to or higher than the melting point, and the value is expressed as an extrapolated value to 190°C on a semi-logarithmic graph, with the reciprocal of absolute temperature on the horizontal axis and the logarithm of the MFR on the vertical axis.

[0016] Two or more types of EVOH may be mixed together to use EVOH (A). In this case, the average values ​​of the ethylene content, degree of saponification and MFR should fall within the above ranges.

[0017] Examples of the acid-modified polyolefin (B) include polyolefins to which an α,β-unsaturated carboxylic acid or its carboxylic anhydride has been added or grafted. The content (addition amount or graft amount) of units derived from the α,β-unsaturated carboxylic acid or its carboxylic anhydride in the acid-modified polyolefin (B) is preferably 0.0005 to 0.5 mol %, more preferably 0.001 to 0.4 mol %, based on the total monomer units, from the viewpoints of dispersibility in EVOH (A) and economic efficiency.

[0018] The α,β-unsaturated carboxylic acid or carboxylic acid anhydride is preferably an α,β-unsaturated carboxylic acid or carboxylic acid anhydride having 3 to 10 carbon atoms. Specific examples include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, itaconic acid, maleic anhydride, and itaconic anhydride, with maleic anhydride and itaconic anhydride being preferred. That is, the acid-modified polyolefin (B) is preferably a polyolefin modified with an α,β-unsaturated carboxylic acid or carboxylic acid anhydride, more preferably an α,β-unsaturated carboxylic acid or carboxylic acid anhydride having 3 to 10 carbon atoms, with maleic anhydride-modified polyolefin and itaconic anhydride-modified polyolefin being even more preferred. Furthermore, the acid-modified polyolefin (B) may contain monomer units derived from multiple types of α,β-unsaturated carboxylic acids or carboxylic acid anhydrides. Examples of the polyolefin include homopolymers such as high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polypropylene, and polybutene-1; copolymers of at least one α-olefin such as ethylene, propylene, 1-butene, 1-hexene, 1-octene, and 4-methyl-1-pentene; and copolymers of an α-olefin with another copolymer component.

[0019] The acid-modified polyolefin (B) may consist of one kind of acid-modified polyolefin or may be a combination of multiple kinds of acid-modified polyolefins.

[0020] The content of the acid-modified polyolefin (B) is preferably 1 to 100 parts by mass, more preferably 10 to 60 parts by mass, and even more preferably 15 to 30 parts by mass, relative to 100 parts by mass of the EVOH (A). By setting the content of the acid-modified polyolefin (B) within the above preferred range, not only is the film formability of the resulting resin composition improved, but also a matte film with excellent stain resistance and aesthetic appeal due to a moderately reduced gloss can be obtained. From the viewpoint of further reducing the gloss, the content of the acid-modified polyolefin (B) may be preferably 17 parts by mass or more or 20 parts by mass or more. On the other hand, from the viewpoint of improving the peel strength, the content of the acid-modified polyolefin (B) may be preferably 27 parts by mass or less or 25 parts by mass or less.

[0021] The inorganic antibacterial agent (C) is preferably an antibacterial agent containing a heavy metal. Here, "heavy metal" includes not only simple heavy metals but also heavy metal ions, heavy metal compounds such as heavy metal oxides or chlorides, and heavy metal complexes. Examples of the heavy metal include metals with antibacterial activity such as silver, copper, and zinc, with silver being preferred. The inorganic antibacterial agent (C) is preferably a metal-supported antibacterial agent, such as a metal ion with antibacterial activity, such as silver ion, copper ion, or zinc ion, supported on a carrier such as zeolite, calcium phosphate, zirconium phosphate, or soluble glass. Silver zeolite is particularly preferred. The inorganic antibacterial agent (C) may consist of one type of inorganic antibacterial agent or a combination of multiple types of inorganic antibacterial agents. The content of the inorganic antibacterial agent (C) is not particularly limited, but is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 3.5 parts by mass, even more preferably 0.3 to 2.5 parts by mass, and most preferably 0.5 to 1.5 parts by mass, relative to 100 parts by mass of the EVOH (A).

[0022] The heavy metal deactivator (D) is not particularly limited as long as it has the function of capturing and stabilizing metal ions by chelating them. Examples include oxalic acid derivatives, salicylic acid derivatives, hydrazide derivatives, triazole derivatives, and imidazole derivatives. Oxalic acid derivatives, salicylic acid derivatives, hydrazide derivatives, and triazole derivatives are preferred because they provide high storage stability for the liquid masterbatch, and salicylic acid derivatives are more preferred because they have excellent heat resistance and compatibility with the diluent resin.

[0023] Preferred examples of the salicylic acid derivatives include N-(2H-1,2,4-triazol-5-yl) salicylamide, dodecanedioic acid bis[N2-(2-hydroxybenzoyl)hydrazide], and 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-N'-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoyl]propanehydrazide, and among these, N-(2H-1,2,4-triazol-5-yl) salicylamide is particularly preferred in that it effectively inhibits discoloration of the resin composition without affecting the antibacterial properties.

[0024] The content of the heavy metal deactivator (D) is preferably 0.05 to 7 parts by mass, more preferably 0.05 to 5 parts by mass, even more preferably 0.1 to 3 parts by mass, and even more preferably 0.1 to 2 parts by mass, relative to 100 parts by mass of EVOH (A). When the content of the heavy metal deactivator (D) is within the above range, a resin composition with even better color can be obtained. Furthermore, when the content of the heavy metal deactivator (D) is 7 parts by mass or less, antibacterial properties are easily maintained and bleeding out tends to be less likely.

[0025] The resin composition of the present invention contains at least one selected from the group consisting of alkali metal salts and alkaline earth metal salts. The total content of alkali metal salts and alkaline earth metal salts in the resin composition of the present invention is 6 μmol / g or more, preferably 8 to 22 μmol / g, and more preferably 10 to 15 μmol / g, calculated as metal. When the total content is 6 μmol / g or more, the adhesiveness (peel strength) and thermal stability of the resulting resin composition are improved. Furthermore, when the total content is 6 μmol / g or more, discoloration due to thermal history during the manufacturing process and the like is likely to occur, so the effects of the present invention are more effectively exhibited. On the other hand, when the total content is 22 μmol / g or less, a resin composition with even better hue can be obtained. Note that the above total content refers to the total content (in terms of metal, number of moles) of alkali metal salts and alkaline earth metal salts relative to the total mass (g) of the resin composition.

[0026] Examples of alkali metal salts and alkaline earth metal salts include sodium salts, potassium salts, magnesium salts, and calcium salts. Among these, sodium salts are preferred from the viewpoint of adhesiveness. The resin composition of the present invention may contain one type of alkali metal salt or alkaline earth metal salt, or may contain two or more types of alkali metal salts or alkaline earth metal salts.

[0027] Examples of sodium salts include sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, various sodium borates such as borax, sodium carbonate, sodium bicarbonate, sodium acetate, sodium propionate, sodium lactate, sodium glycolate, sodium laurate, sodium stearate, etc. Only one type of these sodium salts may be used, or two or more types may be used without any problem.

[0028] The method for incorporating an alkali metal salt and / or alkaline earth metal salt into the resin composition of the present invention is not particularly limited, but examples include a method of preparing a resin composition using EVOH pellets that have been immersed in a solution in which an alkali metal salt and / or alkaline earth metal salt has been dissolved to incorporate a specific amount of alkali metal salt and / or alkaline earth metal salt.

[0029] The resin composition of the present invention may further contain boron compounds such as boric acids, borate esters, and borate salts; carboxylic acid compounds such as carboxylic acids and carboxylic acid salts; and phosphate compounds such as various acids and their salts, such as phosphoric acid and phosphorous acid. The incorporation of one or more of these compounds can improve the water resistance, mechanical properties, and thermal stability during melt molding of the resin composition. While not necessarily limited, the content of the boron compound in the resin composition is preferably 20 to 2,000 ppm in terms of elemental boron, the content of the carboxylic acid compound is preferably 5 to 2,000 ppm, and the content of the phosphate compound is preferably 5 to 300 ppm in terms of phosphate radicals. In this specification, "ppm" means "ppm by mass."

[0030] In addition, the resin composition of the present invention may contain appropriate amounts of plasticizers, antioxidants, pigments, UV absorbers, antistatic agents, crosslinking agents, fillers, and reinforcing agents such as various fibers, provided that the objectives of the present invention are not impaired. In this case, dispersants such as higher fatty acids may be added to improve the dispersibility of these additives, provided that the objectives of the present invention are not impaired. Furthermore, the composition used in the present invention may contain a thermoplastic resin other than an olefin-based resin containing a functional group reactive with a hydroxyl group, provided that the objectives of the present invention are not impaired. The thermoplastic resin may be at least one resin selected from various polyolefins (polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene copolymers, and copolymers of ethylene and α-olefins having 4 or more carbon atoms), polyvinyl chloride, polyvinylidene chloride, polyester, polystyrene, and polyacrylonitrile.

[0031] The total content of the ethylene-vinyl alcohol copolymer (A), acid-modified polyolefin (B), inorganic antibacterial agent (C), heavy metal deactivator (D), alkali metal salt, and alkaline earth metal salt in the resin composition of the present invention is preferably 70% by mass or more, more preferably 90% by mass or more, and in some cases even more preferably 95% by mass or more, 98% by mass or more, or 99% by mass or more.

[0032] The yellowness index (YI) of the resin composition of the present invention is preferably not more than 80, more preferably not more than 60, and even more preferably not more than 40. The lower limit of the yellowness index (YI) is not particularly limited, but is, for example, not less than 5. The yellowness index (YI) is measured by the method described in the examples.

[0033] The resin composition of the present invention can be produced by melt-blending EVOH (A), the inorganic antibacterial agent (C), and the heavy metal deactivator (D) in a single-screw or twin-screw extruder to form masterbatch pellets, and then dry-blending and melt-kneading the masterbatch pellets with EVOH (A) and the acid-modified polyolefin (B). While the EVOH (A), the acid-modified polyolefin (B), the inorganic antibacterial agent (C), and the heavy metal deactivator (D) may be mixed all at once without preparing the masterbatch pellets in advance, the method of preparing the masterbatch pellets in advance is preferred from the viewpoint of obtaining a homogeneous resin composition by improving the dispersion of the inorganic antibacterial agent (C) and the heavy metal deactivator (D).

[0034] A film containing the resin composition of the present invention also constitutes the present invention. The content of the resin composition of the present invention in the film is, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and in some cases even more preferably 95% by mass or more, 98% by mass or more, or 99% by mass or more. There is no particular upper limit to the content, and it is, for example, 100% by mass or less.

[0035] The thickness of the film of the present invention is not particularly limited, but is preferably 5 to 50 μm, more preferably 10 to 30 μm. When the film thickness is equal to or less than the upper limit, it is advantageous in the rapid cooling operation during film formation, and when laminated on a substrate to form wallpaper, the wallpaper is less likely to harden.

[0036] The method for producing the film of the present invention is not particularly limited, but for example, the film can be obtained by melt-molding pellets of the resin composition of the present invention using a conventional T-die method. When obtaining a film using the T-die method, it is preferable to rapidly cool the extruded film. Here, rapid cooling means making the air gap of the die as small as possible and rapidly cooling the film with a cast roll using an air slit.

[0037] The film of the present invention can be laminated on a substrate to form wallpaper, which is an interior material that has excellent adhesiveness and antibacterial properties, is inhibited from discoloring, and has an excellent aesthetic appearance, and is suitable for use in places where antibacterial properties are particularly desired, such as hospitals, restaurants, residences, and public transportation. [Example]

[0038] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Note that, hereinafter, "%" and "parts" are by mass unless otherwise specified.

[0039] Example 1 100 parts of EVOH-1 (ethylene content 44 mol%, saponification degree 99.5 mol%, MFR (190°C, under a 2160 g load) 5 g / 10 min, sodium content 350 ppm) were dry-blended with 4.8 parts of "Zeomic® AV10D" (silver zeolite) manufactured by Sinanen Zeomic Corporation and 0.64 parts of "ADK STAB® CDA-1" (N-(2H-1,2,4-triazol-5-yl) salicylamide) manufactured by ADEKA Corporation under the following conditions to obtain resin composition pellets (masterbatch pellets) containing EVOH (A), an inorganic antibacterial agent (C), and a heavy metal deactivator (D). The moisture content of the pellets was 0.3% or less. EVOH-1 also contained at least sodium acetate as an alkali metal salt. Extruder: Toyo Seiki Labo Plastomill 20mm twin-screw extruder (Plastomill: 4M150 Cylinder: 2D30W2) Extrusion temperature: 170 / 170 / 170 / 170 / 170 / 190℃ Screen: 50 / 100 / 100 / 50 mesh Screw rotation speed: 100 rpm Discharge amount: approx. 3kg / hour

[0040] 100 parts of EVOH-1 were dry-blended with 25.4 parts of Mitsubishi Chemical Corporation's "Modic® H511" acid-modified polyolefin and 23.9 parts of the masterbatch pellets obtained above, to obtain resin composition pellets containing EVOH (A), acid-modified polyolefin (B), inorganic antibacterial agent (C), and heavy metal deactivator (D) under the following conditions. The moisture content of the pellets was 0.3% or less. Extruder: 40mm single screw extruder (GT-40-26 type) manufactured by Plastics Engineering Research Institute Extrusion temperature: 170 / 210 / 210 / 225 / 215 / 210℃ Screen: 50 / 100 / 100 / 50 mesh Screw rotation speed: 25 rpm (shear rate 171.8 cm -1 ) Discharge amount: approx. 7kg / hour

[0041] The resin composition pellets thus obtained were melt-extrusion cast into a film under the following conditions to obtain a film consisting of a resin composition containing EVOH (A), acid-modified polyolefin (B), inorganic antibacterial agent (C), and heavy metal deactivator (D). Extruder: Toyo Seiki Labo Plastomill 20mm single-screw extruder (Plastomill: 4C150 Cylinder: D2020) Die: 300mm wide coat hanger type Extrusion temperature: 170 / 210 / 225 / 215℃ Screen: 50 / 100 / 50 mesh Screw rotation speed: 75 rpm Discharge amount: approx. 2kg / hour Casting roll temperature: 80℃ Line speed: 9m / min Film thickness: 12 μm

[0042] The obtained resin compositions or films were evaluated for the total content of alkali metal salts and alkaline earth metal salts, antibacterial properties (antibacterial activity value), degree of discoloration (yellowing index (YI)), adhesion (peel strength), and gloss using the methods described below. The evaluation results are shown in Table 1.

[0043] <Total content of alkali metal salts and alkaline earth metal salts> 0.5 g of the resulting resin composition pellets were placed in a Teflon pressure vessel manufactured by Actac Corporation, and 5 mL of nitric acid for precision analysis manufactured by Wako Pure Chemical Industries, Ltd. was added. After leaving the vessel for 30 minutes, the vessel was capped with a rupture disk-equipped cap lip. The dried EVOH pellets were decomposed using an Actac Microwave High-Speed ​​Decomposition System (Speedwave MWS-2) at 150°C for 10 minutes, followed by 180°C for 10 minutes. If decomposition of the dried EVOH pellets was not complete, the treatment conditions were adjusted appropriately. The mixture was diluted with 10 mL of ion-exchanged water, and the entire solution was transferred to a 50 mL volumetric flask and adjusted to volume with ion-exchanged water to obtain a decomposed solution. The decomposed solution was analyzed using an ICP atomic emission spectrometer (Optima 4300 DV) manufactured by PerkinElmer Japan, Inc., to quantify the total content (in terms of metals) of alkali metal salts and alkaline earth metal salts.

[0044] <Antibacterial properties (antibacterial activity value)> The antibacterial properties of the obtained film were evaluated according to the method specified in JIS Z2801 under the following evaluation conditions. Bacterial liquid concentration: 1 / 500NB Test solution inoculation volume: 0.4 ml (surface area of ​​coating film: 16 cm 2 ) Storage temperature: 35±1℃ Storage humidity:>90%RH Storage time: 24±1 hours Bacteria used: Staphylococcus aureus (NBRC12732), Escherichia coli (NBRC3972), MRSA (IID1677) Sample size: n=3 The antibacterial activity value was calculated from [Ut] - [At]. The higher the antibacterial activity value, the better the antibacterial property. [Ut]: Common logarithm of the number of viable bacteria on an untreated test piece (polyethylene film) 24 hours after inoculation [At]: Common logarithm of the number of viable bacteria on the obtained film after 24 hours of bacterial culture

[0045] <Degree of discoloration (yellowness index (YI))> The yellowness index (YI) of the obtained resin composition pellets was measured using a spectrophotometer (HunterLab LabScan XE Sensor). The YI value is an index that represents the yellowness of an object, and the higher the YI value, the stronger the yellowness, indicating that the resin composition pellets have been significantly discolored. On the other hand, the lower the YI value, the weaker the yellowness, indicating that discoloration of the resin composition pellets has been suppressed.

[0046] <Adhesion (peel strength)> Using the resulting resin composition, linear low-density polyethylene (Novatec LL-UF943 manufactured by Japan Polyethylene Corporation, hereafter abbreviated as LLDPE), and adhesive resin (DuPont's Bynel CXA417E10 diluted to 7% with the above LLDPE, hereafter abbreviated as Ad), a three-kind, five-layer multilayer film (LLDPE / Ad / resin composition / Ad / LLDPE = 50 μm / 10 μm / 10 μm / 10 μm / 50 μm) was produced. The extruder, extrusion conditions, and die used were as follows: Extruder: For resin compositions: Single-screw extruder (Toyo Seiki ME-type CO-EXT) Diameter 20mmφ, L / D20, full flight screw Feeding section / compression section / metering section / die = 175 / 210 / 220 / 220℃ For LLDPE: Single-screw extruder (GT-32-A manufactured by Plastics Engineering Research Institute) Diameter 32mmφ, L / D28, full flight screw Feeding section / compression section / metering section / die = 150 / 200 / 210 / 220℃ For Ad: Single-screw extruder (Technovel SZW20GT-20mg-STD) Diameter 20mmφ, L / D20, full flight screw Feeding section / compression section / metering section / die = 150 / 200 / 220 / 220℃ Die: 300mm wide, 3-type, 5-layer coat hanger die (manufactured by the Plastics Engineering Research Institute) Film take-up speed: 4m / min The multilayer film extruded from the die was cooled by contacting it with a cooling roll at 80°C.

[0047] The multilayer film obtained 15 minutes after the start of film formation was conditioned at 23°C and 50% RH, and then a sample 150 mm long and 15 mm wide was cut out along the extrusion direction. The peel strength was measured using an Autograph DCS-50M tensile tester manufactured by Shimadzu Corporation when peeled in a T-peel mode at a tensile speed of 250 mm / min under an atmosphere of 23°C and 50% RH. A higher peel strength value indicates better adhesion.

[0048] <Glossiness> The glossiness of the obtained film was evaluated according to the method specified in JIS Z8741 under the following evaluation conditions. Equipment: Gloss Meter VG7000 Nippon Denshoku Industries Co., Ltd. Incident angle 75° / receiving angle 75° The reflectance was measured when light was projected onto the film surface. When the gloss level was 5 to 60 (preferably 10 to 40, more preferably 15 to 30), the gloss level was appropriately reduced, and the aesthetic quality was excellent.

[0049] Examples 2 to 8 Resin compositions and films made from the resin compositions were obtained in the same manner as in Example 1, except that the amounts of each raw material were changed so that the resulting resin compositions had the compositions shown in Table 1. The resulting resin compositions or films were evaluated for the total content of alkali metal salt and alkaline earth metal salt, antibacterial properties (antibacterial activity value), degree of discoloration (yellowing index (YI)), adhesion (peel strength), and gloss using the methods described above. The evaluation results are shown in Table 1.

[0050] Comparative Examples 1 to 5 Resin compositions and films made from the resin compositions were obtained in the same manner as in Example 1, except that the amounts of each raw material were changed so that the resulting resin compositions had the compositions shown in Table 1. The resulting resin compositions or films were evaluated for the total content of alkali metal salt and alkaline earth metal salt, antibacterial properties (antibacterial activity value), degree of discoloration (yellowing index (YI)), adhesion (peel strength), and gloss using the methods described above. The evaluation results are shown in Table 1.

[0051] Comparative Examples 6 to 8 Resin compositions and films made from the resin compositions were obtained in the same manner as in Example 1, except that EVOH-1 was replaced with EVOH-2 (ethylene content 44 mol%, degree of saponification 99.5 mol%, MFR (190°C, under a load of 2160 g) 5 g / 10 min, sodium content 100 ppm) and the amounts of each raw material were changed so that the resulting resin compositions would have the compositions shown in Table 1. EVOH-2 contained at least sodium acetate as an alkali metal salt. The resulting resin compositions and films were evaluated for the total content of alkali metal salts and alkaline earth metal salts, antibacterial properties (antibacterial activity value), degree of discoloration (yellowing index (YI)), adhesion (peel strength), and gloss using the methods described above. The evaluation results are shown in Table 1.

[0052] [Table 1]

[0053] In comparison with Examples 1 to 8, Comparative Examples 1 and 4, which did not contain the acid-modified polyolefin (B), had an insufficient gloss reduction effect (matt finish) and were inferior in aesthetics. Furthermore, Comparative Examples 2 and 5, which did not contain the inorganic antibacterial agent (C), had low antibacterial activity values ​​against Escherichia coli and were inferior in antibacterial properties. Comparative Example 3, which did not contain the metal deactivator (D), suffered from significant discoloration during the film production process. Furthermore, Comparative Examples 6 to 8, which contained a low total content of alkali metal salt and alkaline earth metal salt, did not suffer from discoloration, but had inferior adhesion (peel strength).

Claims

1. A resin composition comprising an ethylene-vinyl alcohol copolymer (A), an acid-modified polyolefin (B), an inorganic antibacterial agent (C), a heavy metal deactivator (D), and at least one selected from the group consisting of an alkali metal salt and an alkaline earth metal salt, wherein the total content of the alkali metal salt and the alkaline earth metal salt is 6 μmol / g or more in terms of metal.

2. 2. The resin composition according to claim 1, wherein the content of the acid-modified polyolefin (B) is 1 to 100 parts by mass per 100 parts by mass of the ethylene-vinyl alcohol copolymer (A).

3. 2. The resin composition according to claim 1, wherein the content of the inorganic antibacterial agent (C) is 0.1 to 5 parts by mass per 100 parts by mass of the ethylene-vinyl alcohol copolymer (A).

4. 2. The resin composition according to claim 1, wherein the content of the heavy metal deactivator (D) is 0.05 to 5 parts by mass per 100 parts by mass of the ethylene-vinyl alcohol copolymer (A).

5. 2. The resin composition according to claim 1, wherein the heavy metal deactivator (D) is at least one selected from the group consisting of oxalic acid derivatives, salicylic acid derivatives, hydrazide derivatives, triazole derivatives, and imidazole derivatives.

6. 2. The resin composition according to claim 1, wherein the heavy metal deactivator (D) is a salicylic acid derivative.

7. The resin composition according to claim 1, wherein the inorganic antibacterial agent (C) is an antibacterial agent containing a heavy metal.

8. A film comprising the resin composition according to any one of claims 1 to 7.

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