Resin composition, film and multilayer structure

Abstract

To provide a resin composition having excellent gas barrier property, particularly oxygen barrier property, under high humidity.SOLUTION: A resin composition contains a hydrophilic resin (X) and a metal compound, satisfying the following formula (1): ΔA2=A2-A2,0>0 (1), (where A2 represents a second virial coefficient when the resin composition is subjected to static light scattering measurement using hexafluoroisopropanol as a solvent, and A2,0 similarly represents the second virial coefficient of the hydrophilic resin (X) in the resin composition and ΔA2 is a value represented by A2-A2,0).SELECTED DRAWING: None

Description

[Technical field]

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

[0002] Hydrophilic resins such as polyvinyl alcohol resins have excellent strength, transparency, and gas barrier properties. Therefore, it is necessary to mold it into a film and use it as a packaging material, especially to prevent deterioration caused by oxygen. It is widely used as a packaging material for important foods, medicines, etc. However, hydrophilic resins are highly susceptible to the effects of humidity because they contain many hydroxyl groups. For example, the gas barrier properties are significantly reduced in a high humidity environment.

[0003] For example, Patent Document 1 describes a film with improved gas barrier properties, which has an average particle size of 500 The water-soluble or water-dispersible polymer compound is included in the water-soluble inorganic fine particles. The poorly soluble inorganic fine particles are selected from the group consisting of aluminum, silicon, zinc, zirconium, silver, and tin. Inorganic compounds or their salts containing one or more essential components, organic acids, inorganic acids and their salts A gas barrier is an ionic crystal synthesized by reacting with one or more compounds selected from the salts of Materials for film are disclosed.

[0004] In addition, Patent Document 2 discloses a method for producing a water-soluble polymer, a metal alkoxide, a hydrolyzate thereof, and tin chloride. and at least one of the general formula (R 1 Si(OR 2 )3)n(where R 1 is an organic functional group, R 2 teeth A gas barrier layer forming composition containing a compound represented by the formula (CH3, C2H5, or C2H4OCH3). The composition is disclosed.

[0005] Furthermore, in Patent Document 3, zinc ions are applied to the surface of a substrate film or a laminate containing the same. and a coating material comprising at least one of a metal alkoxide and a hydrolyzate thereof, and a water-soluble polymer. A method for manufacturing a gas barrier laminate comprising the steps of forming a film and forming a gas barrier layer on the surface of the film. A method for manufacturing the body is disclosed. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2002-338821 A [Patent Document 2] JP 2016-221864 A [Patent Document 3] JP 2018-089567 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the gas barrier films disclosed in the above Patent Documents 1 to 3 are difficult to withstand high humidity conditions. Therefore, the gas barrier properties are insufficient and further improvement is required.

[0008] In the present invention, under such circumstances, the gas barrier property under high humidity, particularly The object of the present invention is to provide a resin composition having excellent oxygen barrier properties. [Means for solving the problem]

[0009] However, the present inventors have discovered a resin composition containing a hydrophilic resin and a metal compound, and the second virial coefficient of the resin composition is smaller than the second virial coefficient of the hydrophilic resin. Only when the solubility is large, the gas barrier property, especially the oxygen barrier property, is excellent under high humidity. Found it.

[0010] That is, the present invention provides a composition comprising a hydrophilic resin (X) and a metal compound and satisfying the following formula (1): The first aspect of the present invention is a resin composition comprising: ΔA2=A2-A 2,0 >0 (1) (A2 above is a static solubility test of the resin composition using hexafluoroisopropanol as a solvent. represents the second virial coefficient when quantitative light scattering measurement was performed, and A 2,0 is the same as the above resin composition represents the second virial coefficient of the hydrophilic resin (X), and ΔA2 is A2-A 2,0 It is a value expressed as: )

[0011] The present invention also provides, in a second aspect, a film containing the resin composition according to the first aspect, A multilayer structure having at least one layer made of the film according to the second aspect of the present invention is also provided as a third aspect of the present invention. This is what we do. Effect of the Invention

[0012] The resin composition of the present invention contains a hydrophilic resin (X) and a metal compound and satisfies the above formula (1). Therefore, a film containing this resin composition is resistant to gases under high humidity conditions. This film has excellent barrier properties, particularly oxygen barrier properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments of the present invention will be described in detail, but the present invention is not limited to these. It is not something that can be determined.

[0014] The resin composition of the present invention contains a hydrophilic resin (X) and a metal compound. Each component will be described.

[0015] <Hydrophilic resin (X)> Specific examples of the hydrophilic resin (X) include vinyl alcohol resins, polysaccharides, Examples of the hydrophilic resin include water-soluble resins such as acrylic resins and polyether resins. X) may be used alone or in combination of two or more kinds.

[0016] Furthermore, the hydrophilic resin (X) has the following properties when made into a film: It is preferable to do so. A film having a thickness of 30 μm was prepared using the hydrophilic resin (X) and was immersed in water at 25° C. for 2 hours. The area change rate when the sample is left to stand for a period of time is 105% or more. It can be calculated using the formula: Area change rate (%) = film area after immersion / film area before immersion × 100 Specific examples of the hydrophilic resin (X) will be described in detail below.

[0017] [Vinyl alcohol resin] The vinyl alcohol resin is usually an ethylene-vinyl alcohol copolymer resin. (ethylene content 20-60 mol%), excluding resins known as , polyvinyl alcohol (hereinafter referred to as "PVA")-based resins, etc.

[0018] The PVA resin is preferably an unmodified PVA resin. A resin may also be used.

[0019] The unmodified PVA resin is usually prepared by polymerizing vinyl ester monomers and then kenolizing them. It can be produced by The modified PVA resin is a polymer of vinyl ester monomer and other unsaturated monomer. It can be produced by saponifying copolymers or by post-modifying unmodified PVA resins. Cut.

[0020] Examples of the vinyl ester monomer include vinyl formate, vinyl acetate, and propionate. Vinyl phosphate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, Vinyl phosphate, vinyl laurate, vinyl stearate, vinyl versatate, trifluoroacetate Aliphatic vinyl esters such as vinyl acetate, aromatic vinyl esters such as vinyl benzoate, etc. Among these, preferred are those having 3 to 20 carbon atoms, more preferably those having 4 to 10 carbon atoms, Particularly preferred are aliphatic vinyl esters having 4 to 7 carbon atoms, and particularly preferred is vinyl acetate. These are usually used alone, but multiple types may be used simultaneously as necessary.

[0021] Examples of the other unsaturated monomers include ethylene, propylene, isobutylene, α- Olefins such as octene, α-dodecene, α-octadecene, acrylic acid, methacrylic acid unsaturated acids such as crotonic acid, maleic acid, maleic anhydride, itaconic acid, etc. Salts or mono- or di-alkyl esters, etc., acrylonitrile, methacrylonitrile, etc. nitriles, amides such as acrylamide and methacrylamide, ethylene sulfonic acid, Olefin sulfonic acids such as allyl sulfonic acid and methallyl sulfonic acid or their salts, Alkyl vinyl ethers, N-acrylamidomethyltrimethylammonium chloride , Allyltrimethylammonium chloride, Dimethylallyl vinyl ketone, N-vinyl Pyrrolidone, vinyl chloride, vinylidene chloride, polyoxyethylene (meth)allyl ether , polyoxyalkylene (meth)allyl ether, etc. ether, polyoxyethylene (meth)acrylate, polyoxypropylene (meth) Polyoxyalkylene (meth)acrylates such as acrylates, polyoxyethylene (meth)acrylates, Polyoxyalkylenes such as polyoxypropylene (meth)acrylamide and polyoxypropylene (meth)acrylamide Kylene (meth)acrylamide, Polyoxyethylene (1-(meth)acrylamide-1 ,1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxyprop Propylene vinyl ether, polyoxyethylene allylamine, polyoxypropylene aryl Examples of the vinyl amine include polyoxyethylene vinyl amine and polyoxypropylene vinyl amine. These can be used alone or in combination of two or more. "(Meth)allyl" refers to allyl or methallyl, and "(meth)acrylate" refers to acrylate. "(Meth)acrylic" means acrylic or methacrylate. Each of these refers to a different

[0022] The PVA resin can be obtained by any known polymerization method, saponification method, or post-modification method. can.

[0023] The amount of the other unsaturated monomer introduced and the amount of modification by post-modification depend on the type of monomer. The amount of introduction and the amount of the aryl group are appropriately set, but are usually 15 mol % or less, and particularly 10 mol % or less. If the amount of modification is too large, the crystallinity of the PVA resin decreases, and the gas barrier properties of the film are deteriorated. tends to decrease.

[0024] The average saponification degree of the PVA resin is usually 70 to 100 mol %, preferably 80 to 10 0 mol %, particularly preferably 85 to 100 mol %, and further preferably 90 to 99.99 mol %. If the average saponification degree is less than 70 mol %, the oxygen permeability becomes large under high humidity conditions. The above average saponification degree is based on JIS K 6726 3.5. To be measured.

[0025] The average degree of polymerization of the PVA resin is usually 100 to 4,000, and preferably 200 The average degree of polymerization is preferably from 300 to 2,500, and more preferably from 300 to 2,500. If the concentration is too high, the mechanical properties such as film strength tend to decrease, and if the concentration is too high, it becomes difficult to form an aqueous solution. The above average degree of polymerization is based on JIS K 6726 It is measured in accordance with.

[0026] In addition, PVA resins are available in a wide range of types and amounts of modification, average saponification degree, average polymerization degree, etc. Two or more types may be used in combination.

[0027] The hydrophilic resin (X) is preferably the main component of the resin composition of the present invention. The content of the hydrophilic resin in the entire composition is usually 80% by weight or more, preferably 90% by weight or more. More preferably, the content is 95% by weight or more. The upper limit is usually 99.99% by weight.

[0028] [Polysaccharides] Examples of the polysaccharides include starch and cellulose. Examples of the starch include natural starches such as corn starch and potato starch, and etherified starches. Starch, esterified starch, cross-linked starch, grafted starch, roasted dextrin, enzyme-modified dextrin Examples of modified starches include thorin, pregelatinized starch, oxidized starch, and the like. Examples of the cellulose include carboxymethyl cellulose, methyl cellulose, Ethyl cellulose, hydroxymethyl cellulose, hydroxypropyl methyl cellulose , Hydroxyethyl cellulose, Hydroxyethyl methyl cellulose, Hydroxypropyl cellulose, nitrocellulose, cationic cellulose, etc., and their sodium salts Examples of such salts include

[0029] [Acrylic resin] Examples of the acrylic resin include polyacrylamide, polyacrylic acid, and the like. and metal salts such as the sodium salt of the above.

[0030] [Polyether resin] Examples of the polyether resin include polyethylene glycol and polypropylene. glycol, etc.

[0031] Among the above hydrophilic resins (X), those having gas barrier properties, particularly oxygen barrier properties, under high humidity conditions are preferred. From the viewpoint of excellent properties, vinyl alcohol resins and polysaccharides are preferred, and PVA resins are particularly preferred. Resins, cellulose, most preferably unmodified PVA resins.

[0032] <Metal compounds> The metal compound used in the present invention has a structure in which metal complexes are layered with a specific interplanar spacing. For example, a metal-containing layered compound such as a layered compound containing Zn as a metal species is used. Some examples include:

[0033] Examples of the metal species contained in the metal compound include Zn, Co, Ni, and Si. These metal species may be contained alone or in combination. In view of its excellent gas barrier properties, particularly oxygen barrier properties, Zn is preferred.

[0034] The metal compound is, for example, at least one metal selected from Zn, Co, Ni, and Si. The metal-containing compound is a compound having a metal group (hereinafter referred to as a "metal-containing compound"). It is obtained by the method. Examples of the metal-containing compound include organic acid salts of metals and inorganic salts of metals. .

[0035] Examples of the organic acid constituting the organic acid salt of the metal include monovalent carboxylic acids such as acetic acid, Dicarboxylic acids such as succinic acid, oxalic acid, and tartaric acid, citric acid, and ethylenediaminetetraacetic acid These may be used alone or in combination of two or more. Good too. The organic acid salt of the metal may be a hydrate or an anhydride. The organic acid salts of the above metals have excellent gas barrier properties, particularly oxygen barrier properties, under high humidity conditions. From this viewpoint, a monovalent metal carboxylate is preferred, and particularly preferred is zinc acetate or a hydrate thereof. It is an object.

[0036] Examples of inorganic salts of the above metals include fluorides, chlorides, bromides, iodides, etc. of metals. These may be used alone or in combination of two or more. The inorganic acid salts of the above metals are excellent in gas barrier properties, particularly oxygen barrier properties, under high humidity conditions. From this viewpoint, metal chlorides are preferred, and zinc chloride or its hydrate is particularly preferred.

[0037] As described above, the metal compound used in the present invention is a compound in which the metal complex is layered with a specific interplanar spacing. Therefore, the hydrophilic resin (X) molecules and the like are present around the metal compound. In the presence of water molecules, the layers of the metal compound are peeled off, and the peeled fine metal complexes The molecules interact with the hydrophilic resin (X) at the molecular level, resulting in excellent gas barrier properties, especially acid resistance. It is presumed that this provides a barrier against water.

[0038] The interlayer distance (the distance between layers) of the metal compound is set to be equal to or smaller than that of the hydrophilic resin (X) or water molecules. From the viewpoint of the interaction, the thickness is preferably 0.01 to 50 nm, and more preferably 0.1 to 30 nm. It is more preferable to do so.

[0039] The molecular weight of the metal complex peeled off from the metal compound is determined based on the molecular level of the hydrophilic resin (X). From the viewpoint of the possibility of interaction, it is preferable that the molecular weight is 100 to 10,000, and more preferably 200 to 2, 000 is particularly preferred.

[0040] In addition, the metal complex is preferably hydrophilic in terms of the interaction with the hydrophilic resin (X). It is preferably aqueous.

[0041] Furthermore, the above metal complexes were not observed even after being left to stand for 1,000 hours at 23°C and 80% RH. It is preferable not to solve the problem.

[0042] The content of the metal compound in terms of metal is 0.01 to 20% by weight based on the resin composition. It is preferable that the content of the ion exchange medium is 0.1 to 8% by weight, more preferably 0.1 to 8% by weight, and particularly preferably 0.2 to 5% by weight. If the content of the metal compound is too low, the gas barrier properties, especially the oxygen barrier properties, under high humidity conditions are poor. The barrier properties tend to decrease, and if the content is too high, the film-forming properties when made into a film, etc. Transparency tends to decrease. In addition, when the resin composition contains a plurality of metal compounds with different metal species, The total amount of metal compounds contained in the material is taken as the content. The content of the above metal compounds is determined by the standard addition method using ICP-MS. can be done.

[0043] [Other ingredients] The resin composition of the present invention generally contains a hydrophilic resin within a range that does not impair the effects of the present invention. Additives to be added to fats, such as heat stabilizers, antioxidants, antistatic agents, colorants, and UV absorbers agents, lubricants, plasticizers, light stabilizers, surfactants, antibacterial agents, drying agents, antiblocking agents, Flame retardant, crosslinking agent, hardener, foaming agent, crystal nucleating agent, anti-fogging agent, biodegradable additive, silane coupling agent The composition may contain a blocking agent, an oxygen absorber, etc. These may be used alone or in combination of two or more kinds. There can be.

[0044] <<Resin composition>> The resin composition of the present invention contains the hydrophilic resin (X) and a metal compound, and is represented by the following formula (1): The present invention is characterized in that it satisfies the following: ΔA2=A2-A 2,0 >0 (1) (A2 above is a static solubility test of the resin composition using hexafluoroisopropanol as a solvent. represents the second virial coefficient when quantitative light scattering measurement was performed, and A 2,0 is the same as the above resin composition represents the second virial coefficient of the hydrophilic resin (X), and ΔA2 is A2-A 2,0 It is a value expressed as: )

[0045] Above A2 and A 2,0 is determined by the following: The resin composition was mixed in hexafluoroisopropanol as a solvent to a solids concentration of 0.1 Five levels of measurement solutions were prepared in the range of up to 1mg / mL, and static light scattering measurements were performed at a temperature of 25°C. The second virial coefficient A2 and weight average of the resin composition obtained from the Zimm plot are Molecular weight Mw b Request. In the same way, the second virial coefficient A of the hydrophilic resin (X) x and weight average molecular weight Mw a of demand. The hydrophilic resin (X) is the same as the hydrophilic resin (X) contained in the resin composition. That is, the resin composition is a hydrophilic resin before containing a metal compound. The resin composition of the present invention contains a hydrophilic resin (X) and a metal compound. The weight average molecular weight of the hydrophilic resin (X) in the composition is the apparent weight average molecular weight of the hydrophilic resin (X). Molecular weight (Mw a ), the second virial obtained by static light scattering measurement of hydrophilic resin (X) is Coefficient A x The second virial coefficient A of the hydrophilic resin (X) in the resin composition 2,0 It is not possible to Therefore, the second virial coefficient A of the hydrophilic resin (X) in the resin composition can be calculated by the following procedure. 2,0 Request. 1) Calculate the constant q from the following equation (2). q=A X / Mw a ν (2) A x : Second virial coefficient obtained by static light scattering measurement of hydrophilic resin (X) Mw a : Weight average molecular weight of hydrophilic resin (X) obtained by static light scattering measurement ν :-0.25 Here, since ν in a good solvent is usually -0.25, calculations are performed assuming ν = -0.25. . 2) The constant q thus obtained and the weight average molecular weight Mw obtained by static light scattering measurement of the resin composition b Using The second virial coefficient A of the hydrophilic resin (X) in the resin composition is calculated from the following formula (3). 2,0 Looking for In addition, the following v is -0.25, the same as in formula (2). A 2,0 =q × Mw b ν (3)

[0046] In the present invention, from the viewpoint of excellent gas barrier properties, particularly oxygen barrier properties, at high humidity, It is necessary that ΔA2 is greater than 0 (ΔA2>0). Preferably, ΔA2>0.0000 5, more preferably ΔA2>0.0001, and particularly preferably ΔA2>0.00 The upper limit is usually 0.01, and preferably 0.1.

[0047] The second virial coefficient indicates the affinity between the polymer chain and the solvent. The second virial coefficient A2 of the resin composition is the second virial coefficient A2 of the hydrophilic resin (X) in the resin composition. Coefficient A 2,0 Since the polymer chain of the resin composition is larger than that of the hydrophilic resin (X), In other words, it has a high affinity with fluoropropanol, which is a highly polar solvent. The resin composition of the present invention has a high affinity with fluorohexane, and is more hydrophilic than the hydrophilic resin (X). Therefore, the resin composition of the present invention has a high gas barrier property under high humidity. This provides the effect of providing excellent barrier properties, particularly excellent oxygen barrier properties.

[0048] The resin composition of the present invention having the above-mentioned characteristics can be prepared, for example, by the following preparation method (i) etc. You can get more.

[0049] <Preparation method (i)> (i-1) a step of mixing a hydrophilic resin (X), a metal-containing compound, and a solvent, and heating and stirring the mixture; (i-2) A step of forming a film from the heated solution and drying it to obtain a film; (i-3) A step of leaving the film at rest under high humidity. Each step will be described in detail below.

[0050] [Step (i-1)] In the above step (i-1), the metal-containing compound reacts in the solvent and undergoes a structural change. This produces a metal compound.

[0051] The amount of the metal-containing compound is usually calculated as metal for 100 parts by weight of the hydrophilic resin (X). The amount is 0.01 to 20% by weight, preferably 0.1 to 8% by weight, and particularly preferably 0.2 to 5 Weight percentages.

[0052] The solvent is not particularly limited as long as it dissolves the hydrophilic resin (X). In order to shorten the drying time after the film formation, for example, methanol, ethanol, etc. Lower alcohols having 1 to 5 carbon atoms, such as n-butanol, propanol, and isopropanol. Coal or the like may be used to the extent that it can dissolve the hydrophilic resin (X). The amount of the solvent is usually 100 to 9.90 parts by weight per 100 parts by weight of the hydrophilic resin (X). 0 part by weight, preferably 400 to 1,900 parts by weight.

[0053] The order in which the hydrophilic resin (X), the metal-containing compound, and the solvent are mixed is not particularly limited. In addition, all of the components may be mixed at once or sequentially. It is preferable to combine (X) with a metal-containing compound from the viewpoint of reactivity.

[0054] The heating temperature is usually 20 to 100°C, preferably 40 to 95°C, and particularly preferably 80 to 100°C. If the heating temperature is too low, the hydrophilic resin (X) tends not to dissolve completely. If the heating temperature is too high, the metal-containing compound tends to decompose.

[0055] The reaction time is usually 0.5 to 5 hours, preferably 1 to 4 hours, and particularly preferably 2 to 3 hours. If the reaction time is too short, the reaction will not proceed sufficiently. However, the reaction yield does not improve and the economic efficiency tends to decrease. The pressure during heating may be normal pressure.

[0056] The metal compound is obtained by the above step (i-1). Then, a hydrogen bond is formed between the hydroxyl group of this metal compound and the hydroxyl group of the hydrophilic resin (X), Or, the metal species of the metal compound interacts with the hydrophilic resin (X) to reduce the amount of gas released under high humidity. It is presumed that this provides the effect of excellent barrier properties, particularly oxygen barrier properties.

[0057] [Step (i-2)] In the step (i-2), a solution containing a hydrophilic resin (X) and a metal compound is formed into a membrane. This is the process of obtaining a film.

[0058] The solid concentration of the solution containing the hydrophilic resin (X) and the metal compound is usually 0.5 to 30 by weight. % by weight, preferably 5 to 20% by weight.

[0059] The film-forming method may be a known method such as a melt extrusion method, a casting method, or a coating method. Any method suitable for forming a film of the hydrophilic resin (X) to be used may be used. For example, when the hydrophilic resin (X) is a PVA-based resin, it is difficult to apply the resin in terms of the accuracy of the film thickness. The method by coating and the casting method are preferred. In addition, the film after the film formation may be stretched uniaxially or biaxially as necessary. It is also possible.

[0060] The coating method may be a bar coater, roll coating, die coating, or graft coating. Known methods such as via coating, comma coating, and screen printing can be used.

[0061] The film may be a single-layer structure film or a multi-layer structure film. The layer structure preferably has at least one layer made of the above-mentioned film. The multilayer structure may be formed by laminating the formed film or by laminating it with another base resin. stomach.

[0062] Examples of the base resin include linear low-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, and Low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-propylene (Block and random) copolymers, ethylene-α-olefins (α- Polyethylene resins such as propylene-α-olefin copolymers, polypropylene, propylene-α-olefin copolymers, etc. Polypropylene resins such as polyolefin (α-olefin with carbon number of 4 to 20) copolymers, Polypentene, polycyclic olefin resins (cyclic olefin structures in the main chain and side chains) (Unmodified) polyolefin resins such as those having at least one of the following properties: Unsaturated carboxylic acids are graft-modified olefins with unsaturated carboxylic acids or their esters. Polyolefin resins in the broad sense, including modified olefin resins such as acid-modified polyolefin resins Fatty acids, ionomers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, Styrene-acrylic acid ester copolymer, polyester resin, polyamide resin (copolymer (including polyamide), polyvinyl chloride, polyvinylidene chloride, acrylic resin, polystyrene Polyethylene, vinyl ester resin, polyester elastomer, polyurethane elastomer Polystyrene elastomers, chlorinated polyethylene, chlorinated polypropylene and other halogenated and substituted polyolefins, aromatic or aliphatic polyketones. The base resin may be subjected to a surface treatment such as a corona treatment.

[0063] The thickness of the film is usually 1 to 200 μm, preferably 1 to 100 μm, and particularly preferably In addition, when the film formed above is a multi-layer structure, the hydrophilic The thickness of all the films obtained by casting a solution containing the reactive resin (X) and a metal compound was The total thickness of the film is determined as the thickness of the film.

[0064] [Step (i-3)] The step (i-3) is a step of leaving the film obtained above under high humidity. By going through this process, the film has excellent gas barrier properties, especially oxygen barrier properties, even under high humidity conditions. The principle by which such an effect is obtained is unclear, but By leaving the film in a humid environment, the metal compounds dispersed in the film react with the hydrophilic resin. It is speculated that they interact or localize at the surface of the film.

[0065] In the present invention, "high humidity" means 20±5° C. and 90±10% RH. The standing time is usually 70 hours or more, preferably 300 hours or more, and more preferably 6 The upper limit of the standing time is usually 1,000 hours.

[0066] By going through the above steps, the resin composition of the present invention (resin composition) that satisfies the above formula (1) can be obtained. A film consisting of the material is obtained. The method for preparing the resin composition is not limited to the above-mentioned preparation method (i), and may be, for example, the following preparation method (i-1 In the process of catalysis, a metal organic acid salt and a strong base (e.g., an alkali metal, an alkaline earth metal The metal compound is first generated by reacting with the hydroxide of the metal, and then the hydrophilic compound is reacted with the hydroxide of the metal. Resin (X) may also be blended.

[0067] The oxygen permeability of the film containing the obtained resin composition was 80cc·3μm / m 2 d ay·atm or less is preferable, and 70cc·3μm / m 2 ·day · atm or less It is more preferable that the density is 55cc·3μm / m 2 ·day·atm or less More preferably, 40cc·3μm / m 2 ·day·atm or less is preferable. 35cc·3μm / m 2 It is more preferable that the temperature is 30 cc·3μm / m 2 ·day·atm or less is more preferable, and 25cc·3μ m / m 2 ·day·atm or less is more preferable, and 20cc·3μm / m 2 d ay·atm or less is more preferable, and 10cc·3μm / m 2 ·day·at It is particularly preferable that the oxygen permeability is less than or equal to 1.0 μm. The lower limit of oxygen permeability is usually 0cc 3μm / m 2 ·day·a tm, and the above oxygen permeability can be determined by an oxygen permeability measuring device.

[0068] The film containing the resin composition of the present invention is very transparent. It is far superior to films containing organic layer compounds or fillers. The film containing the resin composition of the present invention preferably has a haze of 1% or less. More preferably, it is 0.6% or less, even more preferably, it is 0.3% or less, and particularly preferably, it is 0. The haze is 2% or less. The haze is measured in accordance with the JIS K7361-1 standard. For example, ten test pieces of 50 mm x 50 mm are cut from a film. The haze was measured using a haze meter (NDH-4000, manufactured by Nippon Denshoku Co., Ltd.) and the average of 10 sheets was The average value is taken as the haze (%).

[0069] The resin composition of the present invention and a film containing the resin composition are useful as packaging materials. It can be particularly suitably used as a packaging material for food, medicines, etc. EXAMPLES

[0070] The present invention will be described in more detail below with reference to examples, but the present invention will not go beyond the gist of the invention. The present invention is not limited to the following examples unless otherwise specified. In the following, "parts" are based on weight. It means standard.

[0071] Prior to the examples, the following hydrophilic resin (X) was prepared.

[0072] [Hydrophilic resin (X)] PVA-1 (unmodified PVA resin, average degree of polymerization 300, average degree of saponification 99 mol%)

[0073] <Example 1> Add 100 parts of PVA-1 and 0.3 parts of zinc acetate (metal equivalent) to 900 parts of water and stir. The mixture was then heated to 90°C while stirring to dissolve the mixture. The temperature was then maintained at 90°C for 3 hours. After that, it was cooled to room temperature (23°C) to prepare a solution containing the hydrophilic resin (X) and the metal compound. Made. The solution prepared above was applied to a corona-treated PET film with a thickness of 38 μm using a bar coater. The coating was then dried in a hot air dryer at 120°C for 5 minutes. The film was left to stand for 72 hours in an environment of 23° C. and 80% RH to obtain the resin composition film of Example 1. A film (thickness 3 μm) was obtained.

[0074] The second virial coefficients of the resin composition film and PVA-1 obtained above were calculated using the following static It was determined by light scattering measurement.

[0075] [Static Light Scattering Measurement of Resin Composition and Hydrophilic Resin (X)] Only the resin composition film was peeled off from the coating film obtained above. The resin composition film and PVA-1 were each dissolved in hexafluoroisopropanol. Then, five levels of measurement solutions with concentrations ranging from 0.1 to 1 mg / mL were prepared. The mixture was filtered three times using a PTFE membrane filter with a pore size of 0.2 μm. passed. Thereafter, the filtrate was analyzed using a static light scattering photometer (Otsuka Electronics Co., Ltd., SLS-6500). Static light scattering measurements were performed at 25°C for the scattering angle θ of 20 to 150° in 10° intervals. Toluene was used to calibrate the device. The refractive index concentration increment (d n / dc) was measured using a static light scattering measurement solution and a differential refractive index meter (Otsuka Electronics Co., Ltd., DRM-3 The values ​​measured at 25°C were used.

[0076] [Static light scattering analysis] A Zimm plot was created from the scattering intensity obtained by static light scattering measurement, and The weight average molecular weight (Mw b ) and the second virial coefficient A2 were calculated. The weight average molecular weight (Mw) of 1 obtained from static light scattering measurement a ) and the second virial coefficient A x from, The second virial coefficient A of PVA-1 was calculated by the above method. 2,0 asked for. As a result, the second virial coefficient A2 of the resin composition was 0.006532, and PVA-1 The second virial coefficient A 2,0 The second virial coefficient of the resin composition was 0.004822. A2 and the second virial coefficient A of PVA-1 2,0 The difference between A2 and A2 is ΔA2=A2-A 2,0 is 0.00171 It was 0.

[0077] [Oxygen Barrier Properties] The oxygen permeability of the obtained resin composition film was measured using an oxygen permeability measuring device (OX-TRAN1 The measurements were taken at 23°C and 80% RH using a 00A thermocouple (MOCON). The details are shown in Table 1.

[0078] <Example 2> In Example 1, the same procedure was repeated except that the amount of Zn acetate added was 1 part in terms of metal. A resin composition film of Example 2 was obtained in the same manner as in Example 1. The second virial coefficient A2 of the composition was determined in the same manner as in Example 1. The second virial coefficient A 2,0 The difference ΔA2 between Example 1 and The oxygen barrier property was evaluated in the same manner, and the results are shown in Table 1 below.

[0079] <Example 3> In Example 1, the same procedure was repeated except that the amount of Zn acetate added was 5 parts in terms of metal. A resin composition film of Example 3 was obtained in the same manner as in Example 1. The second virial coefficient A2 of the composition was determined in the same manner as in Example 1. The second virial coefficient A 2,0 The difference ΔA2 between Example 1 and The oxygen barrier property was evaluated in the same manner, and the results are shown in Table 1 below.

[0080] <Comparative Example 1> A comparative example was prepared in the same manner as in Example 1, except that Zn acetate was not added. A hydrophilic resin (PVA-1) film of Example 1 was obtained. ΔA2 was 0. The oxygen barrier property was evaluated in the same manner, and the results are shown in Table 1 below.

[0081] <Comparative Example 2> In Example 1, Zn oxide was added in place of Zn acetate so that the amount was 1 part in terms of metal. Other than that, the same procedure as in Example 1 was carried out to obtain a resin composition film of Comparative Example 2. In addition, the second virial coefficient A2 of the resin composition was determined in the same manner as in Example 1. Second virial coefficient A of VA-1 2,0 The difference between them, ΔA2, was -0.004817. In addition, the oxygen barrier property was evaluated in the same manner as in Example 1. The results are shown in Table 1 below.

[0082] <Comparative Example 3> In Example 1, Zn chloride was added in place of Zn acetate so that the amount was 1 part in terms of metal. Other than the above, the resin composition film of Comparative Example 3 was obtained in the same manner as in Example 1. The resin composition film was not dissolved in hexafluoroisopropanol, so the second biphenyl was not dissolved in hexafluoroisopropanol. The real coefficient could not be obtained. The evaluation results are shown in Table 1 below.

[0083] [Table 1]

[0084] As can be seen from Table 1 above, the hydrophilic resin (X) and the metal compound are contained, and ΔA2 is greater than 0. Examples 1 to 3, in which the thickness was large, were excellent in oxygen barrier property under high humidity conditions. On the other hand, Comparative Example 1, which does not contain a metal compound, and Comparative Example 2, in which ΔA2 is 0 or less, All of them were inferior in oxygen barrier properties. In Comparative Example 3, hexafluoroisopropyl was probably produced due to the production of three-dimensional crosslinking reaction products. It was not possible to dissolve it in dopantol, and ΔA2 could not be calculated. The oxygen barrier property of Comparative Example 3 was even inferior to those of Comparative Examples 1 and 2. [Industrial Applicability]

[0085] The resin composition of the present invention has excellent gas barrier properties, particularly oxygen barrier properties, under high humidity conditions. Therefore, it is useful as a packaging material, and is particularly suitable for use as a packaging material for food, medicines, etc. This can be done.

Claims

1. A resin composition comprising a hydrophilic resin (X) and a metal compound, the resin composition being characterized in that the resin composition satisfies the following formula (1): Fat composition. ΔA 2 =A 2 -A 2,0 >0 ・・・(1) (Above A 2 The resin composition was statically mixed in hexafluoroisopropanol as a solvent. represents the second virial coefficient when quantitative light scattering measurement was performed, and A 2,0 is the same as the above resin composition represents the second virial coefficient of the hydrophilic resin (X), and ΔA 2 A 2 -A 2,0 It is a value expressed as: ）

2. The hydrophilic resin (X) is a polyvinyl alcohol resin.

2. The resin composition according to claim 1.

3. The content of the metal compound in terms of metal is 0.01 to 20% by weight based on the resin composition. The resin composition according to claim 1 or 2,

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

5. The oxygen permeability of the above film under an environment of 23°C and 80% RH is 80cc / 3μm / m 2 5. The film according to claim 4, characterized in that it has a viscosity of not more than 1.times.day.atm.

6. A multilayer structure having at least one layer made of the film of claim 4 or 5.

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