Resin composition, film, and multilayer structure

Abstract

To provide a resin composition excellent in gas barrier properties, especially oxygen barrier properties even when exposed to high humidity for a long period of time SOLUTION: The resin composition contains a hydrophilic resin and a metal compound and satisfies the following condition (A): Condition (A): When the resin composition is made into a 10 wt% aqueous solution or aqueous dispersion, and the obtained cast film is allowed to stand for 1 week under conditions of 23 °C. and 80% RH, the following formula (1) is satisfied when the contact angle (°) of water before treatment is α and the contact angle (°) of water after treatment is β. (β - α) ≥ 10 (1) SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition, and more particularly to a resin composition which exhibits high resistance to moisture even when exposed to high humidity for a long period of time. The present invention relates to a resin composition that can provide a film having excellent gas barrier properties. [Background technology]

[0002] Hydrophilic resins such as polyvinyl alcohol resins are excellent in strength, transparency, gas barrier properties, etc. Therefore, it is necessary to form it into a film and use it in various packaging materials, 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 humidity because they have many hydroxyl groups. The gas barrier properties are easily lost in high humidity environments.

[0003] As a film with improved gas barrier properties, for example, Patent Document 1 discloses a film having an average particle diameter of 500 nanometers or less of poorly water-soluble inorganic fine particles and a water-soluble or water-dispersible polymer compound, The hardly soluble inorganic fine particles are selected from 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 The 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, its hydrolyzate, and tin chloride. and at least one of the general formula (R 1 Si(OR 2 )3)n(However, 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 containing at least one of a metal alkoxide and a hydrolyzate thereof, and a water-soluble polymer. 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] Japanese Patent Application Laid-Open No. 2002-338821 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-221864 [Patent Document 3] Japanese Patent Application Publication No. 2018-089567 DISCLOSURE 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 under high humidity conditions. However, the gas barrier properties of the film are insufficient, and further improvement is required.

[0008] Therefore, in this invention, under such circumstances, it is possible to obtain a gas even when exposed to high humidity for a long time. The object of the present invention is to provide a resin composition having excellent barrier properties, particularly excellent oxygen barrier properties. do. [Means for solving the problem]

[0009] However, the present inventors have developed a resin composition containing a hydrophilic resin and a specific metal compound, By using a coating film, it can provide a gas barrier even when exposed to high humidity for a long time. It was found to be superior in

[0010] That is, the present invention provides a resin composition containing a hydrophilic resin and a metal compound, which satisfies the following conditions ( The first aspect of the present invention is a resin composition that satisfies A). Condition (A): The resin composition was made into a 10% by weight aqueous solution or dispersion, and the resulting cast film was The sample was left standing for one week under the conditions of 3°C and 80% RH. The contact angle (°) of water before treatment was α, and the contact angle (°) of water after treatment was α. When the contact angle (°) is β, the following formula (1) is satisfied. (β-α)≧10 (1)

[0011] The present invention also provides, as 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 of the second aspect is also provided as a third aspect. This is what we do. [Effects of the Invention]

[0012] The resin composition of the present invention is a resin composition containing a hydrophilic resin and a metal compound, and satisfies the above conditions. Therefore, a film containing this resin composition can be easily used in high humidity environments. Even when exposed to low temperatures for a long period of time, the gas barrier properties, particularly the oxygen barrier properties, are excellent. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, the embodiments of the present invention will be specifically described, 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 and a metal compound. The constituent components will be explained.

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

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

[0017] [Vinyl alcohol resin] The vinyl alcohol resin is usually an ethylene-vinyl alcohol copolymer resin (ethylene This excludes resins known as those containing 20 to 60 mol% polyethylene, e.g., poly Examples include vinyl alcohol (hereinafter referred to as "PVA")-based resins.

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

[0019] The unmodified PVA resin is usually prepared by polymerizing vinyl ester monomers and then It can be produced by silylating. The modified PVA resin is a polymer of a vinyl ester monomer and another unsaturated monomer. It can be produced by saponifying a polymer or by post-modifying an unmodified PVA resin. 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, caprylic / capric acid Vinyl phosphate, vinyl laurate, vinyl stearate, vinyl versatate, triflate 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 needed.

[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, or the like 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 and polyoxyalkylene (meth)allyl ethers such as polyoxypropylene (meth)allyl ethers. ether, polyoxyethylene (meth)acrylate, polyoxypropylene (meth) Polyoxyalkylene (meth)acrylates such as acrylates, polyoxyethylene (meth)acrylates, Polyoxyalkenyls such as (meth)acrylamide and polyoxypropylene (meth)acrylamide Xylene (meth)acrylamide, Polyoxyethylene (1-(meth)acrylamide-1 ,1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxypropyl Propylene vinyl ether, polyoxyethylene allylamine, polyoxypropylene allylamine Examples of 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" refers to acrylic or methacrylate. Each of these means a different rule.

[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 hydroxybenzoates are appropriately set, but are usually 15 mol % or less, particularly 10 mol % or less. If the amount of modification is too great, the crystallinity of the PVA resin will decrease, and the gas barrier properties will decrease when the film is made. 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 will increase under high humidity conditions. The average degree of saponification mentioned above is measured in accordance with JIS K 6726. do.

[0025] The average degree of polymerization of the PVA resin is usually 100 to 4,000, preferably 200 The average degree of polymerization is preferably 250 to 2500, more preferably 3000 to 3000, and particularly preferably 250 to 2500. If the concentration is too high, 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, amounts, average saponification degrees, average polymerization degrees, etc. Two or more types may be used in combination.

[0027] [Polysaccharide] 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 include modified starches such as thorin, pregelatinized starch, and oxidized starch. Examples of the 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 their sodium salts Examples include metal salts.

[0028] [Acrylic resin] Examples of the acrylic resin include polyacrylamide, polyacrylic acid, and the like. and metal salts such as sodium salts of the above.

[0029] [Polyether resin] Examples of the polyether resin include polyethylene glycol and polypropylene. glycol, etc.

[0030] 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 are more preferred. The preferred are soluble starch and hydroxypropyl methylcellulose, and most preferably unmodified PVOH. A resin.

[0031] 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.

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

[0033] The structural unit may be a metal, a hydroxyl ligand, or an anionic ligand other than a hydroxyl ligand. and is represented by the following chemical formula (1): M a (OH) b A n- (2a-b) / n···(1) (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.)

[0034] In the above chemical formula (1), M may be, for example, Na, K, Ca, Mg, Si, or Al. , Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, etc. These metal species are These may be contained alone or in combination of two or more. From the viewpoint of superiority, Al, Si, Mg, Ni, Co, and Zn are preferable, and Ni, Co, and Zn are particularly preferable. Of these, Zn is particularly preferred.

[0035] In the above chemical formula (1), A may be, for example, RO (alkoxy ligand), ROCO (carboxylic acid ligand), CO3, NO3, SO3, PO4, BO3, F, Br, Cl (R is an alkyl chain, C m H 2m+1 ;m=1~20 in general chemical formula However, the alkyl chain may contain a functional group such as an OH group as long as it does not impair the effects of the present invention. However, A does not include O (oxo ligand). The ionic ligand may be contained alone or in combination with two or more kinds of the hydrophilic resin. From the viewpoint of interaction, NO3, Cl, RO, and ROCO are preferred, and ROCO is particularly preferred. Among these, CH3OCO is particularly preferred.

[0036] The metal compound used in the present invention may contain water molecules.

[0037] Furthermore, when the above metal compounds are measured by wide-angle X-ray diffraction using CuKα rays, they usually exhibit a 2θ It has a main X-ray diffraction peak at 2θ=2 to 15°. It is particularly preferable that the main peak is at 2θ=3 to 8°.

[0038] The wide-angle X-ray diffraction is measured under the following conditions. [Measurement conditions] Equipment used: D8 DISCOVER (manufactured by Bruker Japan) Detector: 2D detector VANTEC-500 (manufactured by Bruker Japan) Voltage: 50kV ·Current: 100mA Camera length: 100mm ·Measurement method: Reflection method Accumulation time: 30 minutes Wavelength: CuKα line (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-dimensional azimuth direction: Azimuth angle (chi)=-180~0° When converting to one-dimensional data in the azimuthal direction, the peak with the strongest diffraction intensity is in the range of 2θ = 2 to 15°. The azimuth angle is made one-dimensional in the range of 1.0° so that it includes the If a peak is observed in the range of 0 to 0°, a diffraction peak is observed in the range of 2θ = 2 to 15°. For example, if a diffraction peak is observed at 2θ=6.8°, it is judged that the peak is observed at 2θ= When the azimuth angle is one-dimensional in the range of 6.0 to 7.0 degrees, the azimuth angle is in the range of -180 to 0 degrees. If a peak is observed in this range, it can be determined that a diffraction peak is observed in the range of 2θ = 2 to 15°. That's fine.

[0039] The interlayer distance (distance between layers) of the metal compound is determined by the interaction with the hydrophilic resin molecules and water molecules. From the viewpoint of function, the thickness is preferably 0.01 to 50 nm, and more preferably 0.1 to 30 nm. The interlayer distance of the metal compound is more preferably 2θ=2 to 1 when analyzed by X-ray diffraction. Calculated from the Bragg equation based on the diffraction position of the strongest peak within a 5° range It is possible.

[0040] The molecular weight of the layered structural unit peeled off from the metal compound is the molecular level of the hydrophilic resin. 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.

[0041] In addition, the layered structural unit is hydrophilic in terms of interaction with the molecules of the hydrophilic resin. It is preferable. Furthermore, the layered structural unit was left standing for 1,000 hours in an environment of 20°C and 90% RH. It is preferable that the polymer does not decompose even when heated.

[0042] Specific examples of the metal compound include a metal layer compound containing Zn as a metal species. Among them, the compound having the chemical formula [Zn5 A Zn-containing layered compound represented by the formula (OH)8(CH3CO2)2·2H2O) is preferred.

[0043] In the present invention, the metal compound and the hydrophilic resin interact with each other to increase the polarity of the hydrophilic resin. It is assumed that this will result in excellent oxygen barrier properties under high humidity conditions. do.

[0044] The metal content of the metal compound in the resin composition of the present invention is 100 parts by weight of hydrophilic resin. The amount is usually 0.01 to 20 parts by weight, preferably 0.1 to 18 parts by weight, particularly preferably If the content of the metal compound is too small, the resin may deteriorate under high humidity conditions. If the content of metal compounds is too high, the oxygen barrier property tends to decrease. When the coating is applied, the coating tends to whiten and lose transparency. In addition, when the resin composition contains a plurality of metal compounds with different metal species, The total amount of all metal compounds contained in the material is the content. The content of the above metal compounds can be determined by the standard addition method using ICP-MS. can be done.

[0045] The metal compound can be prepared by, for example, (I) reacting a metal-containing compound in the presence of a base; (II) It can be obtained by a method of heating a metal-containing compound to cause a reaction.

[0046] Examples of the metal-containing compounds used in the above methods include organic acid metal salts, inorganic metal salts, etc. Examples include:

[0047] Examples of the organic acid constituting the organic acid metal salt include monocarboxylic acids such as acetic acid, Dicarboxylic acids such as citric acid, oxalic acid, and tartaric acid, citric acid, and ethylenediaminetetraacetic acid These may be used alone or in combination of two or more kinds. The organic acid metal salt may be a hydrate or an anhydride. As the organic acid metal salt, monovalent carbohydrate is preferred because it has excellent oxygen barrier properties under high humidity. Metal phosphates are preferred, metal acetates are particularly preferred, and zinc acetate or is its hydrate.

[0048] Examples of the inorganic metal salts include metal fluorides, chlorides, bromides, iodides, and oxides. These may be used alone or in combination of two or more. The metal salt may be a hydrate or anhydrous. As the inorganic metal salt, metal chlorides, etc., are preferred because they have excellent oxygen barrier properties under high humidity conditions. Oxoacids are preferred, and zinc chloride, zinc nitrate, or hydrates thereof are particularly preferred. Each method will be described in detail below.

[0049] [Method (I)] The above method (I) is a method in which a metal-containing compound is reacted in the presence of a base.

[0050] The base used in the above method (I) is, for example, an alkali metal or alkaline earth metal. Among them, the following are preferred because of their excellent reactivity with metal-containing compounds: Alkali metal hydroxides are preferred, with sodium hydroxide being particularly preferred.

[0051] In the reaction of the metal-containing compound with a base, the metal-containing compound and the base are usually reacted in a solution. The hydrophilic resin may be dissolved or dispersed in the above solution. It is preferable to keep the temperature at a constant level from the viewpoint of workability. The method for mixing the metal-containing compound and the base is not particularly limited. For example, a method of mixing a solution in which a metal-containing compound is dissolved with a solution in which a base is dissolved; For example, a method of mixing a slurry liquid in which the substance is dispersed with a solution in which a base is dissolved is exemplified. Among these, from the viewpoint of reaction efficiency, a solution in which a metal-containing compound is dissolved and a solution in which a base is dissolved are preferred. Furthermore, a method in which an organic acid metal salt is used as the metal-containing compound is preferred. In this case, a solution containing a dissolved organic acid metal salt is added to a solution containing a dissolved base and mixed. When an inorganic metal salt is used, a base is dissolved in the solution in which the inorganic metal salt is dissolved. A preferred method is to add the solution containing the hydroxybenzoates and mix them.

[0052] The solvent for dissolving the metal-containing compound and the base is a solvent that can dissolve the metal-containing compound and the base. There are no particular limitations as long as the solvent can be dissolved, and examples thereof include water, methanol, ethanol, 1-propanol, Lower alcohols with 1 to 5 carbon atoms, such as 1-propanol, 2-propanol, 1-butanol, and 2-butanol These may be used alone or in combination of two or more. Among these, water is preferred from the viewpoint of ease of post-treatment.

[0053] The concentration of the metal-containing compound in the solution in which the metal-containing compound is dissolved is usually 0.5 to The concentration is 3 mol / L, preferably 1 to 2 mol / L. The concentration of the base in the solution in which the base is dissolved in the solvent is usually 0.01 to 100 mo 1 / L, preferably 0.1 to 30 mol / L, particularly preferably 1 to 10 mol / L . If the concentrations of the metal-containing compound and the base are lower than the above ranges, the reaction will not proceed sufficiently. Furthermore, if the concentrations of the metal-containing compound and the base are higher than the above ranges, side reactions may occur. tends to occur.

[0054] The molar ratio of the metal-containing compound to the base (metal-containing compound:base) is usually 0.5:2 The ratio is 0.8:1.5 to 1.5:0.8, preferably 0.8:1.5 to 1.5:0.8, and particularly preferably If the molar ratio is outside the above range, the reaction will not proceed sufficiently. There tends to be no

[0055] The pH when reacting the metal-containing compound with the base is usually 4 to 9, preferably If the pH is lower than the above range, the reaction tends not to proceed sufficiently. If the pH is too high, the metal-containing compound produced will decompose. The pH is adjusted by mixing a solution containing a metal-containing compound and a solution containing a base. This is done by the amount of solution used.

[0056] 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 The compound contained tends to decompose due to heat, making it impossible to obtain the desired metal compound. The reaction time is usually 0.5 to 5 hours, preferably 1 to 3 hours. The reaction may be carried out at normal pressure.

[0057] [Method (II)] The above method (II) is a method in which a metal-containing compound is heated to cause a reaction.

[0058] The above method (II) is usually carried out by heating a solution in which a metal-containing compound is dissolved while stirring. In addition, the hydrophilic resin may be dissolved or dispersed in the solution. This is preferable from the viewpoint of workability.

[0059] As the solvent for dissolving the metal-containing compound, the solvents listed in the above method (I) are used. Of these, water and alcohols are preferred, with water being particularly preferred.

[0060] The heating conditions are as follows: the temperature of the solution is usually 20 to 100°C, preferably 50 to 95°C. It is particularly preferable to heat at 70 to 90°C. If the reaction temperature is too low, the reaction may not proceed sufficiently. If the reaction temperature is too high, the metal-containing compound will decompose due to heat, and the desired reaction will not proceed. However, it tends not to be possible to obtain a metal compound having the above properties. The reaction time is usually 0.1 to 100 hours, preferably 0.5 to 30 hours, particularly preferably The reaction time is preferably 1 to 10 hours, and the reaction may be carried out under normal pressure.

[0061] Metal compounds can be obtained by the above methods. Among them, method (II) is preferred from the viewpoint of workability. is preferred. The metal compounds obtained by the above methods are, as described above, compounds represented by the chemical formula (1). The layered structural units are layered at specific interplanar spacings. When hydrophilic resin molecules or water molecules are present around the compound, the metal compound layers are peeled off. These exfoliated fine layered structural units interact with the hydrophilic resin at the molecular level, resulting in It is believed that excellent oxygen barrier properties can be obtained.

[0062] [Other ingredients] The resin composition of the present invention generally contains a resin composition containing a hydroxyl group as long as the effect of the present invention is not impaired. Compounding agents to be added to the product, such as heat stabilizers, antioxidants, antistatic agents, colorants, and ultraviolet absorbers agents, lubricants, plasticizers, light stabilizers, surfactants, antibacterial agents, drying agents, antiblocking agents, Flame retardant, crosslinking agent, curing agent, foaming agent, nucleating agent, anti-fogging agent, biodegradable additive, silane coupling agent These may be used alone or in combination of two or more kinds. You can be there.

[0063] The resin composition of the present invention is a mixture of a hydrophilic resin, a metal compound, and, if necessary, other components. This can be obtained by:

[0064] The resin composition of the present invention contains a hydrophilic resin and a metal compound and satisfies the following condition (A): That is why. Condition (A): The resin composition was made into a 10% by weight aqueous solution or dispersion, and the resulting cast film was The sample was left standing for one week under conditions of 3°C and 80% RH, and the contact angle of water before the treatment (°) was measured. When the contact angle (°) of water after the treatment is α and the contact angle (°) of water after the treatment is β, the following formula (1) is satisfied. (β-α)≧10 (1)

[0065] The difference (β-α) between the contact angle of water after the treatment and the contact angle of water before the treatment is From the viewpoint of excellent gas barrier properties, especially oxygen barrier properties, the value is 10 or more, and 15 or more. The water contact angle is preferably 20 or more at 23°C and 50% Under the condition of RH, 2 μL of purified water was dropped onto the above-mentioned casting film to form a water droplet, and the contact angle Total (DropMaster 500: KYOWA INTERFACE SCIENCE) The contact angle between a water droplet and the surface of the cast film was measured 10 times using a measuring instrument manufactured by Epson Corporation, and the average value was calculated.

[0066] In addition, the contact angle of water after treatment was found to be excellent in gas barrier properties, especially oxygen barrier properties, under high humidity conditions. From this viewpoint, the angle is usually 60° or more, preferably 70° or more, and particularly preferably 75° or more.

[0067] <Film containing resin composition> The film containing the resin composition of the present invention is obtained by forming the resin composition into a film. It is something that can be done.

[0068] The film can be formed by, for example, dissolving a solution ( a method using a coating liquid, a method using an extruder to extrude pellets containing the resin composition of the present invention, Among them, a method using a solution containing a resin composition (coating) In addition, when the coating liquid is used, the solid content concentration is is usually 0.5 to 30% by weight, preferably 5 to 20% by weight.

[0069] The coating solution can be prepared, for example, by adding all the components to a solvent at once and mixing them. and a method in which some components are dissolved in a solvent and other components are added and mixed. Among them, from the viewpoint of workability, it is preferable to add other components to a solution in which a hydrophilic resin is dissolved in a solvent. The method of mixing the components in the above-mentioned order is preferred. From the viewpoint of workability, in the above-mentioned methods (I) and (II) for obtaining metal compounds, When reacting the containing compound, the hydrophilic resin is dissolved or dispersed in the solvent, and after the reaction, the solution is It is also preferable to use the liquid as a coating liquid, and in particular, when a metal compound is obtained by the method (II), In some cases it is preferable. As the solvent, the solvents exemplified for the metal compounds can be used.

[0070] Examples of the film-forming method include a melt extrusion method, an endless belt method, a drum method, and a coating method. Among them, known methods such as a method using a casting method can be used. The method is preferred.

[0071] After forming the film by the above film forming method, the film is dried by heat treatment at 60 to 105°C for 0.5 to 10 minutes, for example. By drying, a film containing the resin composition can be obtained. The film may be stretched uniaxially or biaxially as required.

[0072] The film may be a single-layer structure film or a multi-layer structure film. The multilayer structure preferably has at least one layer made of the film. Furthermore, the multilayer structure may be formed by laminating a film formed by film formation, or by laminating another base resin. It may be possible.

[0073] The thickness of the film containing the resin composition of the present invention is usually 1 to 200 μm, preferably 1 The thickness of the film formed above is preferably from 1 to 100 μm, and particularly preferably from 1 to 50 μm. In the case of a structure, the total thickness of all films containing the resin composition is used as the film thickness. The thickness of the film.

[0074] Examples of the base resin include linear low-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, and polyethylene terephthalate. Low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-propylene (Block and random) copolymers, ethylene-α-olefins (α- with 4 to 20 carbon atoms) Polyethylene resins such as olefin copolymers, polypropylene, propylene-α-olefin Polypropylene resins such as polyolefin (α-olefin with 4 to 20 carbon atoms) copolymers, Polyolefin, polypentene, polycyclic olefin resin (cyclic olefin structure in the main chain and side chain) (Unmodified) polyolefin resins such as polymers having at least one of these Unsaturated carboxylic acids obtained by graft-modifying olefins with unsaturated carboxylic acids or their esters Polyolefin resins in a broad sense, including modified olefin resins such as acid-modified polyolefin resins Fat, ionomer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, Styrene-acrylic ester copolymer, polyester resin, polyamide resin (copolymer (including polyamide), polyvinyl chloride, polyvinylidene chloride, acrylic resin, polystyrene Polyethylene, vinyl ester resin, polyester elastomer, polyurethane elastomer halogenated polyethylene, polystyrene elastomer, chlorinated polypropylene, etc. Examples of the polyolefins include hydroxylated polyolefins, aromatic or aliphatic polyketones, etc. These base resins may be used singly or in combination of two or more. Surface treatment may also be performed.

[0075] The film made of the resin composition of the present invention has excellent properties even when exposed to high humidity for a long period of time. The principle by which such an effect is achieved is not clear. However, when exposed to high humidity for a long time, the molecules of the hydrophilic resin plasticize, causing the film to The metal compounds dispersed in the film interact with the hydrophilic resin or localize on the surface of the film. It is assumed that this is to In the present invention, "long-term exposure to high humidity" refers to exposure to high humidity at 20±5°C and 90±10%RH. This means exposure to an H environment for 70 hours or more.

[0076] In addition, the oxygen permeability of the film after long-term exposure to the above high humidity was 80cc·3μm / m 2 ·day·atm or less is preferable, and 70cc·3μm / m 2 ·day·a It is more preferable that it is tm or less, and 55cc·3μm / m 2 ·day·atm or less It is more preferable to use 30cc 3μm / m 2 ·day·atm or less The oxygen permeability was measured in an environment of 23°C and 80% RH. The lower limit of oxygen permeability is usually 0cc 3μm / m 2 ·day·atm. Also, above The oxygen permeability can be determined by an oxygen permeability measuring device.

[0077] The film containing the resin composition of the present invention is very transparent, and its transparency is 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 0.3% or less, and particularly preferably 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.). The average value is taken as the haze (%).

[0078] The resin composition of the present invention and a film made of the resin composition are useful as packaging materials. It can be suitably used as a packaging material for food, medicines, etc. [Example]

[0079] The present invention will be explained 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.

[0080] Prior to the examples, the following hydrophilic resins were prepared.

[0081] [Hydrophilic resin] [PVA resin] PVA1 (unmodified PVA resin, average degree of polymerization 300, average degree of saponification 99 mol%) PVA2 (modified PVA resin, average degree of polymerization 450, average degree of saponification 98 mol%) PVA3 (unmodified PVA resin, average degree of polymerization 400, average degree of saponification 88 mol%) [Polysaccharide] Starch (water-soluble starch, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., starch (soluble)) Hydroxypropyl methylcellulose (Mitsubishi Chemical Foods, Hypromellose AW) -4)

[0082] Example 1 Add 100 parts of PVA1 and 1 part of Zn acetate (metal equivalent) to 900 parts of water and mix while stirring. The temperature was raised to 90°C and dissolved. After that, the mixture was stirred for 3 hours while maintaining the temperature at 90°C. The mixture was cooled to room temperature (23°C) to prepare a solution of the resin composition. After adjusting the solid content to 10% by weight using water, a film was formed by a casting method and heated at 120°C for 5 minutes. The resin composition film (thickness: 3 μm) was obtained by drying in a hot air dryer for 1 minute. . The resin composition film is laminated to a thickness of 30 μm or more, and then the laminate is subjected to the above-mentioned method. Wide-angle X-ray diffraction was performed according to the method described in Example 1. As a result, a diffraction peak was observed at 2θ=6.2°.

[0083] <Example 2> In Example 1, PVA1 was changed to PVA2, and the amount of Zn acetate added was A resin composition film (thickness 3 μm) was prepared in the same manner as in Example 1, except that the total weight of the resin composition was 1.5 parts. ) was obtained. In addition, wide-angle X-ray diffraction was carried out in the same manner as in Example 1. As a result, Diffraction peaks were observed.

[0084] Example 3 In Example 2, the same procedure was repeated except that the amount of Zn acetate added was 10 parts in terms of metal. A resin composition film (thickness: 3 μm) was obtained in the same manner as in Example 2. Similarly, wide-angle X-ray diffraction was performed, and a diffraction peak was observed at 2θ=6.2°.

[0085] Example 4 In Example 1, except that PVA1 was changed to hydroxypropyl methylcellulose. A resin composition film (thickness: 3 μm) was obtained in the same manner as in Example 1. Similarly, wide-angle X-ray diffraction was performed, and a diffraction peak was observed at 2θ=6.2°.

[0086] <Example 5> A resin composition was prepared in the same manner as in Example 1, except that PVA1 in Example 1 was changed to starch. A composite film (thickness: 3 μm) was obtained. Wide-angle X-ray diffraction was also performed in the same manner as in Example 1. As a result, a diffraction peak was observed at 2θ=6.2°.

[0087] Example 6 Resin was prepared in the same manner as in Example 1, except that PVA1 was changed to PVA3. A resin composition film (thickness: 3 μm) was obtained. In addition, wide-angle X-ray diffraction was performed in the same manner as in Example 1. As a result, a diffraction peak was observed at 2θ=6.2°.

[0088] <Comparative Example 1> P was prepared in the same manner as in Example 1, except that Zn acetate was not added. A film of VA1 (thickness: 3 μm) was obtained. In addition, wide-angle X-ray diffraction was performed in the same manner as in Example 1. As a result, no diffraction peaks were observed at 2θ=2 to 15°.

[0089] <Comparative Example 2> In Example 2, P was prepared in the same manner as in Example 2, except that Zn acetate was not added. A film of VA2 (thickness: 3 μm) was obtained. In addition, wide-angle X-ray diffraction was performed in the same manner as in Example 1. As a result, no diffraction peaks were observed at 2θ=2 to 15°.

[0090] <Comparative Example 3> In Example 4, the same procedure as in Example 4 was carried out except that Zn acetate was not added. A hydroxypropylmethylcellulose film (thickness: 3 μm) was obtained. As a result, no diffraction peaks were observed in the range of 2θ = 2 to 15°. Ta.

[0091] <Comparative Example 4> The same procedure as in Example 5 was repeated except that Zn acetate was not added. A powder film (thickness: 3 μm) was obtained. Wide-angle X-ray diffraction was also performed in the same manner as in Example 1. As a result, no diffraction peak was observed at 2θ=2 to 15°.

[0092] <Comparative Example 5> In Example 6, P was prepared in the same manner as in Example 6, except that Zn acetate was not added. A VA3 film (thickness: 3 μm) was obtained. Wide-angle X-ray diffraction was performed in the same manner as in Example 1. As a result, no diffraction peaks were observed at 2θ=2 to 15°.

[0093] [Contact angle] The films of Examples 1 to 6 and Comparative Examples 1 to 5 obtained above were subjected to a temperature of 23°C and 50% RH. Then, 2 μL of purified water was dropped onto the film to form a water droplet, and a contact angle meter (DropMast er 500: manufactured by KYOWA INTERFACE SCIENCE) The contact angle with the rubber surface was measured 10 times, and the average value was taken as the contact angle (α) of water before treatment. The contact angle of water after leaving these films under high humidity conditions of 23°C and 80%RH for one week ( The results are shown in Table 1 below.

[0094] [Oxygen barrier properties] Oxygen permeability of the films of Examples 1 to 6 and Comparative Examples 1 to 5 after standing for one week under the above-mentioned high humidity conditions The oxygen permeability was measured using an oxygen permeability measuring device (OX-TRAN100A, manufactured by MOCON Co., Ltd.). The measurements were carried out under the conditions of °C and 80% RH. The results are shown in Table 1 below.

[0095] [Table 1]

[0096] As can be seen from Table 1 above, the product contains hydrophilic resin and metal compound, and is processed for a long time under high humidity. The difference between the contact angle of water after treatment (β) and the contact angle of water before treatment (α) is 10 or more. 1 to 6 were excellent in oxygen barrier properties under high humidity conditions. On the other hand, in Comparative Examples 1 to 5, the difference between the water contact angles (β) and (α) was less than 10. The barrier properties were poor. [Industrial Applicability]

[0097] 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 for film coating, comprising a polyvinyl alcohol resin and a metal layer compound, wherein the metal species of the metal layer compound is at least one selected from the group consisting of Ni, Co, and Zn.

2. 2. The resin composition for film coating according to claim 1, wherein the polyvinyl alcohol resin is an unmodified polyvinyl alcohol resin.

3. 3. The resin composition for film coating according to claim 2, wherein the content of said metal layer compound in terms of metal is 0.01 to 20 parts by weight per 100 parts by weight of said unmodified polyvinyl alcohol resin.

4. A resin composition for film coating according to claim 1 or 2, characterized in that the interlayer distance of the metal layered compound is 0.01 to 50 nm.

5. A resin composition for film coating according to claim 1 or 2, characterized in that the metal layered compound is a Zn-containing layered compound.

6. A film comprising the resin composition for film coating according to any one of claims 1 to 5.

7. A film for packaging materials, characterized by containing a resin composition for film coating described in any one of claims 1 to 5.

8. The oxygen permeability of the film under an environment of 23°C and 80% RH is 80cc.3µm / m 2 8. The film according to claim 6, wherein the film has a viscosity of not more than 1000 sq. m.day atm.

9. A multilayer structure having at least one layer made of the film of claim 6.