Resin composition, film and multilayer structure

Abstract

To provide a resin composition which is excellent in gas barrier property under high humidity, and is particularly excellent in oxygen barrier property.SOLUTION: A resin composition contains a hydrophilic resin, and a metallic compound, wherein when the resin composition is formed into a film, oxygen permeability (cc 3 μm / m2 day atm) under the environment at 23°C and 80% RH satisfies the following expression (1): oxygen permeability (cc 3 μm / m2 day atm)≤80.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a resin composition, and more particularly, to a resin composition capable of obtaining a film having high gas barrier properties under high humidity conditions.

Background Art

[0002] Hydrophilic resins such as polyvinyl alcohol-based resins are excellent in strength, transparency, gas barrier properties, etc. Therefore, they are formed into films and widely used as various packaging materials, particularly packaging materials for foods, pharmaceuticals, etc. where suppression of deterioration by oxygen is essential. However, since hydrophilic resins have many hydroxyl groups, they are greatly affected by humidity and their gas barrier properties are significantly reduced in a high humidity environment.

[0003] As a film with improved gas barrier properties, for example, in Patent Document 1, water-insoluble inorganic fine particles with an average particle size of 500 nm or less and a water-soluble or water-dispersible polymer compound are included, and the above water insoluble inorganic fine particles are an inorganic compound or a salt thereof having one or more selected from aluminum, silicon, zinc, zirconium, silver, and tin as essential components, and an organic acid, an inorganic acid, and a salt thereof A gas barrier film material which is an ionic crystal synthesized by reacting one or more compounds selected from these salts is disclosed.

[0004] Further, in Patent Document 2, a gas barrier layer forming composition containing a water-soluble polymer, at least one of a metal alkoxide, a hydrolyzate thereof, and tin chloride and a compound represented by the general formula (R 1 Si(OR 2 )3)n (wherein R 1 is an organic functional group, R 2 is CH3, C2H5, or C2H4OCH3) is disclosed.​​​​ A product is disclosed.

[0005] Furthermore, in Patent Document 3, on the surface of a base film or a laminate containing the same, a coating film containing zinc ions, at least one of a metal alkoxide and its hydrolyzate, and a water-soluble polymer is formed, and a gas barrier laminate body manufacturing method including a step of forming a gas barrier layer on the said surface is disclosed. Furthermore, in Patent Document 3, on the surface of a base film or a laminate containing the same, a coating film containing zinc ions, at least one of a metal alkoxide and its hydrolyzate, and a water-soluble polymer is formed, and a gas barrier laminate body manufacturing method including a step of forming a gas barrier layer on the said surface is disclosed. Furthermore, in Patent Document 3, on the surface of a base film or a laminate containing the same, a coating film containing zinc ions, at least one of a metal alkoxide and its hydrolyzate, and a water-soluble polymer is formed, and a gas barrier laminate body manufacturing method including a step of forming a gas barrier layer on the said surface is disclosed. A method for manufacturing a gas barrier laminate including a step of forming a coating film containing zinc ions, at least one of a metal alkoxide and its hydrolyzate, and a water-soluble polymer on the surface of a base film or a laminate containing the same, and a step of forming a gas barrier layer on the said surface is disclosed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Disclosure of the Invention

Problems to be Solved by the Invention

[0007] However, the gas barrier films disclosed in Patent Documents 1 to 3 above do not have sufficient gas barrier properties under high humidity, and further improvement is required. However, the gas barrier films disclosed in Patent Documents 1 to 3 above do not have sufficient gas barrier properties under high humidity, and further improvement is required.

[0008] Therefore, in the present invention, under such circumstances, an object is to provide a resin composition excellent in gas barrier properties, particularly oxygen barrier properties, under high humidity. Therefore, in the present invention, under such circumstances, an object is to provide a resin composition excellent in gas barrier properties, particularly oxygen barrier properties, under high humidity. Therefore, in the present invention, under such circumstances, an object is to provide a resin composition excellent in gas barrier properties, particularly oxygen barrier properties, under high humidity.

Means for Solving the Problems

[0009] However, the inventors of the present invention, in a resin composition containing a hydrophilic resin and a metal compound, by increasing the average metal atom concentration near the film surface when made into a film, high However, the inventors of the present invention, in a resin composition containing a hydrophilic resin and a metal compound, by increasing the average metal atom concentration near the film surface when made into a film, high It has been found that it has excellent oxygen barrier properties under humidity.

[0010] That is, the present invention is a resin composition containing a hydrophilic resin and a metal compound, and when the resin composition is formed into a film, the oxygen permeability (cc·3μm / m 2 ·day·atm) under the environment of 23°C and 80% RH satisfies the following formula (1). The resin composition is the first gist. Oxygen permeability (cc·3μm / m 2 ·day·atm) ≤ 80 ···(1)

[0011] Further, the present invention is a resin composition containing a hydrophilic resin and a metal compound, and when the resin composition is formed into a film, the resin composition that satisfies the following formula (2) is the second gist. α - β ≥ 1 ···(2) (Where α is the average metal atom concentration (%) within the range of 0 to 9 nm in depth from the film surface, and β is the average metal atom concentration (%) within the range of 12 to 21 nm in depth from the film surface .)

[0012] Furthermore, the present invention takes a film containing the resin composition of the first gist or the resin composition of the second gist as the third gist, and further takes a multilayer structure having at least one layer composed of the film of the third gist as the fourth gist.

Effect of the Invention

[0013] The present invention is a resin composition containing a hydrophilic resin and a metal compound, and when the resin composition is formed into a film, the oxygen permeability (cc·3μm / m 2 · ·day·atm) under the environment of 23°C and 80% RH satisfies the following formula (1). Oxygen permeability (cc·3μm / m 2·day·atm) ≦ 80 ···(1) Therefore, when this resin composition is formed into a film, it can be made into a film excellent in oxygen barrier properties under high humidity conditions.

[0014] The present invention also relates to a resin composition containing a hydrophilic resin and a metal compound, and is a resin composition that satisfies the following formula (2) when the resin composition is formed into a film. α - β ≧ 1 ···(2) (Wherein α represents the average metal atom concentration (%) within the range of 0 to 9 nm from the film surface, and β represents the average metal atom concentration (%) within the range of 12 to 21 nm from the film surface.) Therefore, when this resin composition is formed into a film, it can be made into a film excellent in oxygen barrier properties under high humidity conditions.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments for carrying out the present invention will be specifically described, but the present invention is not limited thereto.

[0016] The resin composition of the present invention contains a hydrophilic resin and a metal compound. Hereinafter, each constituent will be described.

[0017] 〔Hydrophilic Resin〕 Specific examples of the hydrophilic resin used in the present invention include, for example, water-soluble resins such as vinyl alcohol-based resins, polysaccharides, acrylic resins, and polyether resins. The above hydrophilic resins may be used alone or in combination of two or more.

[0018] In addition, the above hydrophilic resin preferably has the following characteristics when formed into a film, for example. ​​​​​​​That is, using the above hydrophilic resin, a film with a thickness of 30 μm was prepared and immersed in water at 25°C It is preferable that the area change rate when standing and immersing for 2 hours is 105% or more. Note that the above The area change rate can be obtained by the following formula. Area change rate (%) = (film area after immersion / film area before immersion) × 100 Hereinafter, specific hydrophilic resins will be described in detail.

[0019] [Vinyl alcohol-based resin] The above vinyl alcohol-based resin generally excludes resins known as ethylene-vinyl alcohol copolymer resins (ethylene content 20 to 60 mol%), and examples include poly vinyl alcohol (hereinafter referred to as "PVA")-based resins and the like.

[0020] The above PVA-based resin is preferably an unmodified PVA resin, but a modified PVA-based resin may also be used.

[0021] The above unmodified PVA resin can generally be produced by polymerizing a vinyl ester-based monomer and then saponifying it. In addition, the above modified PVA-based resin can be produced by saponifying a copolymer of a vinyl ester-based monomer and another unsaturated monomer, or by post-modifying an unmodified PVA resin.

[0022] Examples of the above vinyl ester-based monomer include vinyl formate, vinyl acetate, propion ic acid vinyl, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, cap rylic acid vinyl, lauric acid vinyl, stearic acid vinyl, versatic acid vinyl, trif loroacetic acid vinyl and other aliphatic vinyl esters, benzoic acid vinyl and other aromatic vinyl esters, etc. include. Among them, preferably those having 3 to 20 carbon atoms, more preferably 4 to 10 carbon atoms, particularly preferably aliphatic vinyl esters having 4 to 7 carbon atoms, and especially preferably vinyl acetate . These are usually used alone, but a plurality of types may be used simultaneously if necessary.

[0023] Examples of the other unsaturated monomers include olefins such as ethylene, propylene, isobutylene, α- octene, α-dodecene, α-octadecene, unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid or salts or mono- or dialkyl esters thereof, nitriles such as acrylonitrile, methacrylonitrile, amides such as acrylamide, methacrylamide, olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid or salts thereof, alkyl vinyl ethers, N-acrylamidomethyltrimethylammonium chloride , allyltrimethylammonium chloride, dimethylallyl vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinylidene chloride, polyoxyethylene (meth)allyl ether , polyoxypropylene (meth)allyl ether and other polyoxyalkylene (meth)allyl ethers, polyoxyethylene (meth)acrylate, polyoxypropylene (meth)acrylate and other polyoxyalkylene (meth)acrylates, polyoxyethylene (meth)acrylamide, polyoxypropylene (meth)acrylamide and other polyoxyalkylene (meth)acrylamides, polyoxyethylene (1-(meth)acrylamide-1 ,1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxypropylene vinyl ether, etc. ,1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxypropylene ,1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxypropylene Ropylene vinyl ether, polyoxyethylene allylamine, polyoxypropylene allyl amine, polyoxyethylene vinylamine, polyoxypropylene vinylamine, etc. can be mentioned. These can be used alone or in combination of two or more. In addition, the above “(meth)allyl” means allyl or methallyl, “(meth)acrylate” means acrylate or methacrylate, and “(meth)acrylic” means acrylic or methacrylic respectively.

[0024] The above PVA-based resin can be obtained by any known polymerization method, saponification method, and post-modification method.

[0025] In addition, the introduction amount of the above other unsaturated monomer and the modification amount by post-modification are appropriately set according to the type of monomer, but usually they are 15 mol% or less, particularly 10 mol% or less. If the introduction amount and the modification amount are too large,

[0026] the crystallinity of the PVA-based resin decreases, and the gas barrier property when made into a film tends to decrease. The average saponification degree of the above PVA-based resin is usually 70 to 100 mol%, preferably 80 to 10 0 mol%, particularly preferably 85 to 100 mol%, and even more preferably 90 to

[0027] 99.99 mol%. If the average saponification degree is less than 70 mol%, the oxygen permeability under high humidity tends to increase. In addition, the above average and the mechanical properties such as film strength tend to decrease, and if it is too high, it becomes difficult to form an aqueous solution etc., and there is a tendency for handling to become difficult. The above average degree of polymerization is based on JIS K 6726 and is measured.

[0028] Also, as the PVA-based resin, two or more types with different modification types, modification amounts, average saponification degrees, average degrees of polymerization, etc. may be used in combination.

[0029] [Polysaccharides] Examples of the above polysaccharides include starch, cellulose, etc. Examples of the above starch include natural starches such as corn starch and potato starch, and modified starches such as etherified starch, esterified starch, crosslinked starch, grafted starch, baked dextrin, enzyme-modified dextrin, alpha-starch, oxidized starch, etc. Examples of the above cellulose include carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, hydroxyethyl methyl cellulose, hydroxypropyl cellulose, nitrocellulose, cationized cellulose, etc., and metal salts such as their sodium salts.

[0030] [Acrylic resin] Examples of the above acrylic resin include polyacrylamide, polyacrylic acid, and metal salts such as their sodium salts.

[0031] [Polyether resin] Examples of the above polyether resin include polyethylene glycol, polypropylene glycol, etc.

[0032] ​​​​​​​​​Among the above hydrophilic resins, vinyl acetate is preferred because of its excellent oxygen barrier properties under high humidity conditions. Alcohol-based resins and polysaccharides are preferred, and PVA-based resins and modified starch (particularly soluble Modified starch), hydroxypropyl methylcellulose, and most preferably unmodified PVA-based It is a resin.

[0033] The hydrophilic resin is preferably the main component of the resin composition of the present invention, and the entire resin composition The content of the hydrophilic resin in the body is usually 80% by weight or more, preferably 90% by weight or more, particularly The upper limit is usually 99.99% by weight.

[0034] [Metal compound] The metal compound used in the present invention has specific structural units arranged in layers with specific interplanar spacing. It is preferable that the compound has a structure as follows.

[0035] The structural units are metals, hydroxyl ligands, anionic ligands other than hydroxyl ligands, and is represented by the following chemical formula (3): M a (OH) b A n- (2a-b) / n (3) (The above M represents a metal species, and A represents an anionic ligand other than a hydroxyl ligand having a valence of n-. However, A does not include O (oxo ligand). n is an integer of 1 or more, and a and b are 0. It is a larger number and satisfies a / b=0.1~10.)

[0036] In the above chemical formula (3), M is, for example, Na, K, Ca, Mg, Si, Al. , Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, etc. These metal species are These may be used alone or in combination of two or more. From the excellent points, Al, Si, Mg, Ni, Co, and Zn are preferable, and Ni, Co, and Zn are particularly preferable, and Zn is especially preferable.

[0037] Also, in the above chemical formula (3), as A, for example, RO (alkoxy ligand), ROCO (carboxylic acid ligand), CO3, NO3, SO3, PO4, BO3, F, Br, Cl etc. can be mentioned (R is an alkyl chain, C m H 2m+1 ; m = 1 to 20 is generally represented by the chemical formula. However, as long as the effects of the present invention are not inhibited, the alkyl chain may have a functional group such as an OH group ). However, O (oxo ligand) is excluded as A. These anionic ligands may be contained alone or in two or more kinds. Among them, from the viewpoint of the interaction with the hydrophilic resin, NO3, Cl, RO, and ROCO are preferable, ROCO is particularly preferable, and among them, CH3OCO is especially preferable.

[0038] The metal compound used in the present invention may contain water molecules.

[0039] Also, when the above metal compound is measured by wide-angle X-ray diffraction using CuKα rays, it preferably has a main peak of X-ray diffraction at 2θ = 2 ~15°. Further, it preferably has a main peak at 2θ = 2 to 9°, and it is particularly preferable to have a main peak at 2θ = 3 to 8° .

[0040] Note that the above wide-angle X-ray diffraction is measured under the following conditions. [Measurement conditions] · Equipment used: D8 DISCOVER (manufactured by Bruker Japan) · Detector: Two-dimensional detector VANTEC-500 (manufactured by Bruker Japan) · Voltage: 50 kV · Current: 100 mA · Camera length: 100 mm · Measurement method: Reflection method · Integration time: 30 minutes · Wavelength: CuKα ray (Kα1 and Kα2 are not separated) · Detector position: 2θ = 10° · X-ray incident angle: θ = 0.3° · Conditions for one-dimensionalization in the 2θ direction: 2θ = 0 to 35°, azimuth angle (chi) = -95 to -85° · One-dimensionalization in the azimuth angle direction: azimuth angle (chi) = -180 to 0° When one-dimensionalizing in the azimuth angle direction, the peak with the strongest diffraction intensity in the range of 2θ = 2 to 15° is included and one-dimensionalized in the azimuth angle direction within a range of 1.0°. At this time, the azimuth angle -18 If a peak is observed in the range of 0 to 0°, it is determined that a diffraction peak is observed in the range of 2θ = 2 to 15° For example, when a diffraction peak is observed at 2θ = 6.8°, 2θ = When one-dimensionalized in the azimuth angle direction in the range of 6.0 to 7.0°, if a peak is observed in the range of azimuth angle = -180 to 0° it can be determined that a diffraction peak is observed in the range of 2θ = 2 to 15°. That's all.

[0041] The interlayer distance (distance between layers) of the above metal compound is preferably 0.01 to 50 nm, more preferably 0.1 to 30 nm, from the point of interaction with the molecules of the hydrophilic resin and water molecules. The interlayer distance of the above metal compound can be calculated from Bragg's equation based on the diffraction position of the peak with the strongest intensity in the range of 2θ = 2 to 1 5° when analyzed by X-ray diffraction method. The molecular weight of the layered structural unit exfoliated from the above metal compound is preferably 100 to 10,000, more preferably 200 to 2, from the point that interaction is possible at the molecular level of the hydrophilic resin.

[0042] The molecular weight of the layered structural unit exfoliated from the above metal compound is preferably 100 to 10,000, more preferably 200 to 2, from the point that interaction is possible at the molecular level of the hydrophilic resin. It is particularly preferable that it is 000.

[0043] Further, from the viewpoint of interaction with the molecules of the hydrophilic resin, the above-mentioned layered structural unit is hydrophilic which is preferable. Furthermore, it is preferable that the above-mentioned layered structural unit does not decompose even when left standing for 1,000 hours in an environment of 20 ° C and 90% RH .

[0044] Specific examples of the above metal compound include, for example, a layered compound containing Zn as a metal species . Among them, from the viewpoint of excellent oxygen barrier properties under high humidity, a Zn-containing layered compound represented by the chemical formula [Zn5(OH)8(CH3CO2)2·2H2O] is preferable.

[0045] In the present invention, it is presumed that the metal compound and the hydrophilic resin interact with each other, and the polarity of the hydrophilic resin becomes high , thereby obtaining an effect of excellent oxygen barrier properties under high humidity.

[0046] The metal-converted content of the metal compound in the resin composition is usually 0.01 to 10 parts by weight, preferably 0.1 to 8 parts by weight, and particularly preferably 0. 2 to 4 parts by weight with respect to 100 parts by weight of the hydrophilic resin. If the content of the metal compound is too small, the oxygen barrier property under high humidity tends to decrease, and if the content of the metal compound is too high, whitening and a decrease in transparency tend to occur when forming a film or the like. When the resin composition contains a plurality of metal compounds having different metal species, the total amount of all the metal compounds contained in the resin composition is taken as the content. In addition, the content of the above metal compound can be determined by the standard addition method using ICP-MS.

[0047] The above metal compound can be obtained, for example, by the method of reacting a metal-containing compound under a base, (II) or by a method such as heating and reacting the metal-containing compound, etc.

[0048] Examples of the metal-containing compound used in each of the above methods include organic acid metal salts, inorganic metal salts, etc. and the like.

[0049] Examples of the organic acid constituting the above organic acid metal salt include monovalent carboxylic acids such as acetic acid, co dicarboxylic acids such as succinic acid, oxalic acid, tartaric acid, and trivalent or higher carboxylic acids such as citric acid and ethylenediaminetetraacetic acid and the like. These may be used alone or in combination of two or more. Also, the organic acid metal salt may be a hydrate or an anhydride. As the above organic acid metal salt, from the viewpoint of excellent oxygen barrier properties under high humidity, monovalent carboxylic acid metal salts are preferable, particularly preferably metal acetate salts, and especially preferably zinc acetate or its hydrate.

[0050] Examples of the above inorganic metal salts include metal fluorides, chlorides, bromides, iodides, oxo acids, etc. These may be used alone or in combination of two or more. Also, the inorganic metal salt may be a hydrate or an anhydride. As the above inorganic metal salt, from the viewpoint of excellent oxygen barrier properties under high humidity, metal chlorides, oxo acids are preferable, particularly preferably zinc chloride, zinc nitrate or their hydrates. Hereinafter, each method will be described in detail.

[0051] [Method of (I)] The above method of (I) is a method of reacting a metal-containing compound under a base. Examples of the base used in the above method of (I) include alkali metals or alkaline earth metals Examples include metal hydroxides. Among them, since it has excellent reactivity with metal-containing compounds, hydroxides of alkali metals are preferred, and sodium hydroxide is particularly preferred.

[0052] In the reaction between the above metal-containing compound and the base, usually, the metal-containing compound and the salt in the solution can be mixed with the base for reaction. The method of mixing the above metal-containing compound and the base is not particularly limited. For example, a method of mixing a solution in which the metal -containing compound is dissolved with a solution in which the base is dissolved, a method of mixing a slurry liquid in which the metal-containing compound is dispersed with a solution in which the base is dissolved, etc. can be mentioned. Among them, from the viewpoint of reaction efficiency, a method of mixing a solution in which the metal-containing compound is dissolved with a solution in which the base is dissolved is preferred. Further, when an organic acid metal salt is used as the metal-containing compound, a method of adding and mixing a solution in which the organic acid metal salt is dissolved to a solution in which the base is dissolved is preferred. When an inorganic metal salt is used, a method of adding and mixing a solution in which the base is dissolved to a solution in which the inorganic metal salt is dissolved is preferred.

[0053] As the solvent for dissolving the above metal-containing compound and the base, there is no particular limitation as long as it can dissolve the metal-containing compound and the base. For example, water, methanol, ethanol, 1-pro panol, 2-propanol, 1-butanol, 2-butanol and other lower alcohols having 1 to 5 carbon atoms can be mentioned. These may be used alone or in combination of two or more. Among them, water is preferred from the viewpoint of easy post-treatment.

[0054] The concentration of the metal-containing compound in the solution in which the metal-containing compound is dissolved is usually 0.5 to 3 mol / L, preferably 1 to 2 mol / L. In addition, the concentration of the base in the solution obtained by dissolving the base in a solvent is usually 0.01 to 100 mo l / L, preferably 0.1 to 30 mol / L, and particularly preferably 1 to 10 mol / L. . If the concentrations of the metal-containing compound and the base are too low compared to the above ranges, the reaction tends not to proceed sufficiently. Also, if the concentrations of the metal-containing compound and the base are too high compared to the above ranges, side reactions tend to occur.

[0055] The molar ratio of the above metal-containing compound to the base (metal-containing compound: base) is usually 0.5:2 to 2:0.5, preferably 0.8:1.5 to 1.5:0.8, and particularly preferably 0.9:1.2 to 1:1. If the molar ratio is outside the above range, the reaction tends not to proceed sufficiently.

[0056] In addition, the pH when reacting the metal-containing compound with the base is usually 4 to 9, and preferably 5 to 8. When the pH is too low compared to the above range, the reaction tends not to proceed sufficiently. Also, when the pH is too high compared to the above range, the formed metal-containing compound tends to decompose. Note that the pH is adjusted by adjusting the amounts of the solution in which the metal-containing compound is dissolved and the solution in which the base is dissolved. used.

[0057] The reaction temperature in the above reaction is usually 15 to 60 °C, preferably 20 to 40 °C. If the reaction temperature is too low, the reaction tends not to proceed sufficiently, and if the reaction temperature is too high, the metal -containing compound decomposes due to heat, and the target metal compound tends not to be obtained. In addition, the reaction time is usually 0.5 to 5 hours, preferably 1 to 3 hours, and the pressure during the reaction may be normal pressure.

[0058] After the above reaction, the metal compound is obtained as a precipitate. The obtained metal compound may be used as it is, but it is preferably used after purifying the metal compound by washing, grinding operations, etc.

[0059] [Method (II)] The method (II) above is a method of heating and reacting a metal-containing compound. The method (II) above is usually carried out by heating a solution in which a metal-containing compound is dissolved while stirring.

[0060] As the solvent for dissolving the metal-containing compound, the solvents listed in the method (I) above can be used. Among them, water and alcohols are preferable, and water is particularly preferable.

[0061] As the above heating conditions, the temperature of the solution is usually 20 to 100 °C, preferably 50 to 95 °C. , particularly preferably 70 to 90 °C. If the reaction temperature is too low, the reaction tends not to proceed sufficiently. If the reaction temperature is too high, the metal-containing compound decomposes by heat, and the target metal compound tends not to be obtained. Also, the reaction time is usually 0.1 to 100 hours, preferably 0.5 to 30 hours, particularly preferably 1 to 10 hours, and the pressure during the reaction may be normal pressure.

[0062] After the above reaction, the metal compound is obtained as a precipitate. The obtained metal compound may be used as it is. It may also be used after purifying the metal compound by washing, grinding operations, etc.

[0063] Generally, the metal compound refers to, for example, metal salts, metal oxides, metal complexes, simple metals or alloys, etc. However, the metal compounds obtained by the above respective methods are, as described above, the said chemical ​A metal having a structure in which the layered structural unit represented by formula (1) is layered at a specific interplanar spacing is a layered compound. Therefore, in an environment where hydrophilic resin molecules and water molecules are present around the metal compound, the layers of the metal compound are peeled off, and as a result of the interaction between the peeled fine layered structural units and the hydrophilic resin at the molecular level, it is presumed that excellent oxygen barrier properties can be obtained.

[0064] [Other components] In the resin composition of the present invention, within a range that does not inhibit the effects of the present invention, generally, compounding agents compounded in resin compositions, such as heat stabilizers, antioxidants, antistatic agents, coloring agents, ultraviolet absorbers, lubricants, plasticizers, light stabilizers, surfactants, antibacterial agents, desiccants, antiblocking agents, flame retardants, crosslinking agents, curing agents, foaming agents, crystal nucleating agents, antifogging agents, biodegradable additives, silane coupling agents, oxygen absorbers, etc. may be contained. These can be used alone or in combination of two or more.

[0065] The resin composition of the present invention can be obtained by mixing a hydrophilic resin, a metal compound, and, if necessary, other components.

[0066] [Resin composition] The resin composition of the present invention contains a hydrophilic resin and a metal compound, and the oxygen permeability (cc·3μm / m ·day 2 ·atm) at 23°C and 80% RH when the above resin composition is formed into a film satisfies the following formula (1). Oxygen permeability (cc·3μm / m 2 ·day·atm) ≤ 80 ···(1)

[0067] The above oxygen permeability needs to be 80 cc·3μm / m 2 ·day·atm or less. ​​​​​​​Yes. Preferably 70 cc·3 μm / m 2 ·day·atm or less, more preferably 55 c c·3 μm / m 2 ·day·atm or less, even more preferably 30 cc·3 μm / m 2 ·da y·atm or less, particularly preferably 20 cc·3 μm / m 2 ·day·atm or less, particularly even more preferably 15 cc·3 μm / m 2 ·day·atm or less, particularly even more preferably is 10 cc·3 μm / m 2 ·day·atm or less, most preferably 5 cc·3 μm / m 2 · day·atm or less. The lower limit of the oxygen permeability is usually 0 cc·3 μm / m 2 ·d ay·atm. In the present invention, the oxygen permeability can be determined by an oxygen permeability measuring device .

[0068] In addition, the resin composition of the present invention satisfies the following formula (2) when formed into a film. α - β ≧ 1 ···(2)

[0069] The above "α" represents the average metal atom concentration (%) within the range of 0 to 9 nm in depth from the surface of the film, and the above "β" represents the average metal atom concentration (%) within the range of 12 to 21 nm in depth from the surface of the film.

[0070] In the present invention, α - β needs to be 1 or more, preferably 2 or more, more preferably 3 or more. If α - β is less than the above numerical value, the gas barrier property under high humidity decreases. The upper limit of α - β is usually 50.

[0071] The above average metal atom concentration is measured using an X-ray photoelectron spectrometer under the following measurement conditions as follows [X-ray photoelectron spectrometer measurement conditions] · Equipment used: JPS-9030 (manufactured by JEOL Ltd.) · Excitation X-ray source: Unmonochromatized AlKa, output 12 kV, 25 mA (300 W) · Analyzer mode: CAE mode (constant energy resolution mode) · Resolution: EP: 50, energy step 1 eV EP: 30, energy step 0.2 eV · Analysis area: φ6 mm

[0072] The metal element of the average metal atom concentration measured using the above X-ray photoelectron spectrometer is preferably derived from the above metal compound [II].

[0073] In the present invention, when made into a film, by increasing the average metal atom concentration near the surface of the film it becomes excellent in gas barrier properties, particularly oxygen barrier properties, under high humidity conditions To obtain such a resin composition, for example, a method of allowing the resin composition to stand under high humidity etc. may be mentioned. Among them, a method of allowing a film containing the resin composition to stand under high humidity is preferred Preferably

[0074] <Film containing the resin composition> The film containing the resin composition of the present invention is obtained by forming a film of the composition containing the above resin composition and is preferably obtained by forming a film of the above resin composition as such

[0075] As a method for forming the above film, for example, a method using a solution or dispersion (coating solution) of the resin composition, or a pellet-like composition containing the resin composition of the present invention is extruded using a method, etc Methods such as melt molding using an extruder can be mentioned. Among them, a method using a solution or dispersion liquid (coating liquid) of the resin composition is preferable. Also, the solid content concentration in the case of using the above coating liquid is usually 0.5 to 30% by weight, preferably 5 to 20% by weight. In the case of using the above coating liquid, the solid content concentration is usually 0.5 to 30% by weight, preferably 5 to 20% by weight. In the case of using the above coating liquid, the solid content concentration is usually 0.5 to 30% by weight, preferably 5 to 20% by weight.

[0076] The preparation of the above coating liquid includes, for example, a method of charging all components into a solvent at once and mixing them, a method of adding other components to a solution in which some components are dissolved in a solvent and mixing them, etc. The preparation of the above coating liquid includes, for example, a method of charging all components into a solvent at once and mixing them, a method of adding other components to a solution in which some components are dissolved in a solvent and mixing them, etc. Among them, from the viewpoint of workability, a method of adding other components to a solution in which a hydrophilic resin is dissolved in a solvent and mixing them is preferable. Among them, from the viewpoint of workability, a method of adding other components to a solution in which a hydrophilic resin is dissolved in a solvent and mixing them is preferable. Also, in the method of obtaining the above metal compound, when reacting a metal-containing compound, it is also preferable to dissolve a hydrophilic resin in a solvent, and from the viewpoint of workability, it is particularly preferable when obtaining a metal compound by the method of (II) above. Also, in the method of obtaining the above metal compound, when reacting a metal-containing compound, it is also preferable to dissolve a hydrophilic resin in a solvent, and from the viewpoint of workability, it is particularly preferable when obtaining a metal compound by the method of (II) above. Also, in the method of obtaining the above metal compound, when reacting a metal-containing compound, it is also preferable to dissolve a hydrophilic resin in a solvent, and from the viewpoint of workability, it is particularly preferable when obtaining a metal compound by the method of (II) above. As the above solvent, the solvents mentioned for the above metal compound can be used, and among them, water is preferable. As the above solvent, the solvents mentioned for the above metal compound can be used, and among them, water is preferable.

[0077] As the above film-forming method, for example, known methods such as a melt extrusion method, an endless belt method, a drum method, and a casting method such as a casting method can be adopted. Among them, a method by a casting method is preferable, and a method by a coating method is particularly preferable. As the above film-forming method, for example, known methods such as a melt extrusion method, an endless belt method, a drum method, and a casting method such as a casting method can be adopted. Among them, a method by a casting method is preferable, and a method by a coating method is particularly preferable. As the above film-forming method, for example, known methods such as a melt extrusion method, an endless belt method, a drum method, and a casting method such as a casting method can be adopted. Among them, a method by a casting method is preferable, and a method by a coating method is particularly preferable.

[0078] Examples of the above coating method include known methods such as a bar coater, roll coating, die coating, gravure coating, comma coating, and screen printing. Examples of the above coating method include known methods such as a bar coater, roll coating, die coating, gravure coating, comma coating, and screen printing. Examples of the above coating method include known methods such as a bar coater, roll coating, die coating, gravure coating, comma coating, and screen printing.

[0079] After coating, it is dried by heat treatment at, for example, 60 to 105°C for 0.5 to 10 minutes. Thus, a film made of the resin composition can be obtained. Further, the above film may be subjected to stretching operations such as uniaxial stretching or biaxial stretching as required.

[0080] The above film may be a single-layer film or a multilayer structure. The above multilayer structure preferably has at least one layer made of the above film. Further, the above multilayer structure may be formed by laminating the formed film, or may be laminated with another base resin.

[0081] The thickness of the film containing the resin composition of the present invention is usually 0.1 to 200 μm, preferably 0.2 to 100 μm, and particularly preferably 0.3 to 50 μm. When the above-formed film is a multilayer structure, the total thickness of all the films containing the resin composition is regarded as the thickness of the film.

[0082] Examples of the above base resin include polyethylene-based resins such as linear low-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-propylene (block and random) copolymers, ethylene-α-olefin (α-olefin having 4 to 20 carbon atoms) copolymers, polypropylene-based resins such as polypropylene, propylene-α-ole fin (α-olefin having 4 to 20 carbon atoms) copolymers, polybutene, polypentene, polycyclic olefin-based resins (polymers having a cyclic olefin structure in at least one of the main chain and side chains), etc. (unmodified) polyolefin-based resins, and modified polyolefin-based resins such as unsaturated carboxylic acid-modified polyolefin-based resins obtained by graft-modifying these polyolefins with unsaturated carboxylic acids or their esters, including polyolefin-based resins in a broad sense. ​ Fats, ionomers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, e thylene-acrylic ester copolymers, polyester resins, polyamide resins (including co polymers), polyvinyl chloride, polyvinylidene chloride, acrylic resins, polysty rene, vinyl ester resins, polyester elastomers, polyurethane elastomers, polysty rene elastomers, chlorinated polyethylenes, chlorinated polypropylenes, etc. Haloge nated polyolefins, aromatic or aliphatic polyketones, etc. may be mentioned. These m ay be used alone or in combination of two or more. Further, these base resins m ay be subjected to surface treatment such as corona treatment.

[0083] As described above, by allowing the film containing the resin composition of the present invention to stand under high humidity, the film satisfies the above formulas (1) and (2). Therefore, the film has excellent gas barrier properties, particularly oxygen barrier properties, under high humidity. Although the principle by which such an effect is obtained is not clear, it is presumed that by allowing the film to stand under high humidity, the molecules of the hydrophilic resin are plasticized, and the metal compound dispersed in the film interacts with the hydrophilic resin or localizes on the surface of the film. In the present invention, "under high humidity" means 20 ± 5°C and 90 ± 10% RH.

[0084] Also, the standing time is usually 70 hours or more, preferably 100 hours or more, more preferably 1 50 hours or more. The upper limit of the standing time is usually 1,000 hours.

[0085] The film containing the resin composition of the present invention is very excellent in transparency, and its transparency is non- It is far superior to films containing layered compounds or fillers. Specifically, the film containing the resin composition of the present invention preferably has a haze of 1% or less, more preferably 0.6% or less, even more preferably 0.3% or less, and particularly preferably 0. 2% or less. The above haze is the HAZE value measured in accordance with the standard of JIS K7361-1. For example, 10 test pieces of 50 mm × 50 mm are cut from the film, measured using a haze meter (NDH-4000 manufactured by Nippon Denshoku Industries Co., Ltd.), and the average value of the 10 pieces is taken as the haze (%).

[0086] The resin composition of the present invention and the film made of the resin composition are useful as packaging materials, and can be particularly preferably used as packaging materials for foods, pharmaceuticals, etc.

Examples

[0087] Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the description of the examples as long as the gist is not exceeded. In the examples, "parts" and "%" mean weight basis unless otherwise specified.

[0088] Prior to the examples, the following hydrophilic resins were prepared.

[0089] 〔Hydrophilic resin〕 [PVA-based resin] ·PVA (unmodified PVA resin, average degree of polymerization 300, average saponification degree 99 mol%) [Polysaccharide] ·Hydroxypropylmethylcellulose (HPMC) (manufactured by Mitsubishi Chemical Foods Co., Ltd., Hypromellose AW)

[0090] <Example 1> To 900 parts of water, 100 parts of PVA and 1 part of Zn(CH3COO)2·2H 2O in terms of metal were added, and the mixture was heated and stirred at 90 °C for 3 hours to prepare a resin composition (coating solution). The obtained coating solution was applied to the corona-treated surface of a PET substrate with a thickness of 38 μm using a wire bar #18, dried at 80 °C for 5 minutes, and a two-layer film with a film layer composed of a resin composition having a thickness of 2.2 μm laminated on the PET substrate was obtained. The obtained film was allowed to stand for 200 hours under humidity conditioning conditions of 23 °C and 80% RH to prepare a film.

[0091] <Example 2> In Example 1, the amount of Zn(CH3COO)2·2H2O to be added was changed to 0.3 part in terms of metal based on 100 parts of PVA, and a film was produced in the same manner as in Example 1 except that the thickness of the film layer composed of the resin composition was made 3 μm, and it was prepared under the same humidity conditioning conditions.

[0092] <Example 3> In Example 1, a film was produced in the same manner as in Example 1 except that the thickness of the film layer composed of the resin composition was made 0.4 μm, and it was prepared under the same humidity conditioning conditions.

[0093] <Example 4> In Example 1, PVA was changed to HPMC, and a film was produced in the same manner as in Example 1 except that the thickness of the film layer composed of the resin composition was made 1.7 μm, and it was prepared under the same humidity conditioning conditions.

[0094] <Example 5> In Example 1, the amount of Zn(CH3COO)2·2H2O to be added was changed to 10 parts in terms of metal based on 100 parts of PVA, and a film was produced in the same manner as in Example 1 except that the thickness of the film layer composed of the resin composition was made 3 μm. ​​​​​​​​​Except for this, the film was produced in the same manner as in Example 1 and conditioned under the same humidity conditions.

[0095] <Comparative Example 1> In Example 1, except that the thickness of the film layer made of the resin composition was 3.5 μm and the film was not conditioned for humidity, the film was produced in the same manner as in Example 1.

[0096] [Wide-angle X-ray diffraction (XRD) measurement] The films of Examples 1 to 5 and Comparative Example 1 obtained above were subjected to wide-angle X-ray diffraction (X RD) measurement under the following conditions. [Measurement conditions] Equipment used: D8 DISCOVER (manufactured by Bruker Japan) Voltage: 50 kV Current: 100 mA Camera length: 150 mm Measurement method: Reflection method Integration time: 20 minutes

[0097] As a result of the measurement, main peaks were detected at 2θ = 6.8°, 13.5°, and 20.2° in the films of Examples 1 to 5. These were consistent with the Zn-containing layered compound described in Inorg. Chem. 2013, 52, 95-10 2. Therefore, the metal compound contained in the films of Examples 1 to 5 was identified as the Zn-containing layered compound [Zn5(OH)8(CH3CO2)2·2H2O]. Also, when the films of Examples 1 to 5 were measured by wide-angle X-ray diffraction, the interlayer distance was calculated from Bragg's equation based on the diffraction position at 2θ = 6.8° where the peak intensity was the strongest. As a result, the above mentioned Zn-containing layered compound [Zn5(OH)8(CH3CO2)2·2H2O] was a layered compound with an interlayer distance of 1.3 nm. On the other hand, in the film of Comparative Example 1, the main peaks detected in the films of Examples 1 to 5 were not detected. ​​​​

[0098] <X-ray Photoelectron Spectroscopy Measurement> Using the X-ray photoelectron spectrometer for the two-layer films of Examples 1 to 5 and Comparative Example 1 obtained above the average Zn atomic concentration (%) within the range of 0 to 9 nm in depth from the surface of the film layer made of the resin composition, and the average within the range of 12 to 21 nm in depth from the surface of the film layer Zn atomic concentration (%) was measured. The measurement conditions are as follows. The measurement conditions are as follows. [Measurement Conditions] · Equipment used: JPS-9030 (manufactured by JEOL Ltd.) · Excitation X-ray source: Unmonochromatized AlKa, output 12 kV, 25 mA (300 W) · Analyzer mode: CAE mode (constant energy resolution mode) · Resolution: EP: 50, energy step 1 eV EP: 30, energy step 0.2 eV · Analysis area: φ6 mm

[0099] 〔Oxygen Barrier Property〕 From the two-layer films of the Examples and Comparative Example obtained above, a film layer made of the resin composition was taken out, and the oxygen permeability of the taken-out film layer was measured using an oxygen permeability measuring device (OX-TR AN100A, manufactured by MOCON) under the environment of 23°C and 80% RH. From the two-layer films of the Examples and Comparative Example obtained above, a film layer made of the resin composition was taken out, and the oxygen permeability of the taken-out film layer was measured using an oxygen permeability measuring device (OX-TR

[0100]

Table 1

[0101] As can be seen from Table 1 above, the films of Examples 1 to 5 had an oxygen permeability of 80 cc·3 μm / m 2 ·day·atm or less and were excellent in oxygen barrier property. Also, the film of Comparative Example 1 had an oxygen permeability of 100 cc·3μm / m when measured under condition (X)2 ·da exceeded y·atm and was inferior in oxygen barrier properties.

[0102] Furthermore, the films of Examples 1 to 5 containing a hydrophilic resin and a metal compound and having α-β of 1 or more were excellent in oxygen barrier properties under high humidity. On the other hand, the film of Comparative Example 1 having α-β less than 1 was inferior in oxygen barrier properties under high humidity.

Industrial Applicability

[0103] Since the resin composition of the present invention is excellent in oxygen barrier properties under high humidity, it is useful as a packaging material and can be particularly preferably used as a packaging material for foods, pharmaceuticals, and the like.

Claims

1. A resin composition comprising a hydrophilic resin and a metal compound, wherein the resin composition is formed into a film When measured, the oxygen permeability at 23°C and 80% RH environment (cc·3μm / m 2 ·day·a tm) satisfies the following formula (1). A resin composition characterized by this. Oxygen permeability (cc·3μm / m 2 ·day·atm) ≤ 80 ··· (1)

2. A resin composition comprising a hydrophilic resin and a metal compound, wherein the resin composition is formed into a film When formed, it is a resin composition characterized by satisfying the following formula (2). α－β≧１ ・・・（２） (Wherein α is the average metal atom concentration (%) within the range of 0 to 9 nm in depth from the film surface, β represents the average metal atom concentration (%) within the range of 12 to 21 nm in depth from the film surface .)

3. The metal content in terms of metal of the above metal compound is 0.01 to 1 10 parts by weight with respect to 100 parts by weight of the hydrophilic resin. The resin composition according to claim 1 or 2, characterized by this.

4. A film characterized by containing the resin composition according to any one of claims 1 to 3 。

5. The oxygen permeability of the above film at 23 ° C. and 80% RH environment is 20 cc·3 μm / m 2 The film according to claim 4, characterized in that it is as follows: ·day·atm

6. Characterized by having at least one layer composed of the film according to claim 4 or 5 Multilayer structure.

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