Resin composition, film and multilayer structure

Abstract

To provide a resin composition that has excellent gas barrier properties, especially oxygen barrier properties under high humidity conditions.SOLUTION: A resin composition contains a polyvinyl alcohol resin. When the resin composition is made into a film, a degree of oxygen permeation (cc 3 μm / m2 day atm) at 23°C and 80%RH satisfies the following formula (1): degree of oxygen permeation (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 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] Polyvinyl alcohol resins are excellent in strength, transparency, and gas barrier properties. It is molded into a film and used as a packaging material for various products, especially for food and medicines that need to be protected from deterioration due to oxygen. It is widely used as a packaging material for items such as food. However, polyvinyl alcohol resins have many hydroxyl groups and are easily damaged by humidity. It is highly susceptible to the effects of moisture, and its gas barrier properties deteriorate significantly in high humidity environments.

[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 CH 3 , C 2 H5 , or C 2 H 4 OCH 3 A gas barrier layer-forming composition comprising a compound represented by the formula (I) 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 DISCLOSURE OF THEINVENTION [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. 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 under high humidity conditions. do. [Means for solving the problem]

[0009] However, the present inventors have found that in a resin composition containing a polyvinyl alcohol resin, By suppressing the molecular mobility of the amorphous structure of polyvinyl alcohol resin, It was found that the film has excellent oxygen barrier properties.

[0010] That is, the present invention relates to a resin composition containing a polyvinyl alcohol-based resin, When the resin composition was made into a film, the oxygen permeability (cc·3μ) was measured at 23°C and 80% RH. m / m 2 According to a first aspect of the present invention, there is provided a resin composition in which the modulus of elasticity (MPa) of the resin composition satisfies the following formula (1): Oxygen permeability (cc 3μm / m 2 ·day·atm)≦80 ···(1)

[0011] The present invention also provides a resin composition containing a polyvinyl alcohol-based resin, When the solid-state NMR of the product was measured under the following conditions, the T 1C ( 13 A resin composition consisting of two components with a C spin-lattice relaxation time of 50 seconds or less. The composition is the second gist of the present invention. conditions: The resin composition was packed into a 4 mm diameter zirconia rotor and then subjected to a 9.4 T static NMR. Under magnetic field ( 1 H: Resonance frequency 400MHz, 13 C: Resonance frequency 100MHz) 23℃, Seriously The sample was rotated at 5,000 Hz under high-angle spinning conditions.

[0012] The present invention relates to a resin composition according to the first aspect or a resin composition according to the second aspect. The third aspect of the present invention is a film containing the above-mentioned The fourth gist of the present invention is a multilayer structure having at least one layer. Effect of the Invention

[0013] The present invention relates to a resin composition containing a polyvinyl alcohol-based resin, When made into a film, oxygen permeability (cc 3μm / m 2 · day·atm) satisfies the following formula (1). Oxygen permeability (cc 3μm / m 2 ·day·atm)≦80 ···(1) Therefore, when this resin composition is made into a film, it has excellent oxygen barrier properties under high humidity conditions. It is possible to obtain a film having excellent properties.

[0014] The present invention also provides a resin composition containing a polyvinyl alcohol-based resin, When the solid-state NMR measurement of the product was performed under the above conditions, the T 1C ( 13 C spin-lattice relaxation time) consists of two components, one of which is less than 50 seconds. Therefore, when this resin composition is formed into a film, it has excellent oxygen barrier properties under high humidity conditions. It can be a film. Above T 1c The components with a melting point of 50 seconds or less are derived from the amorphous structure of polyvinyl alcohol resin. Polyvinyl alcohol resins, which are made up of a large number of components derived from an amorphous structure, have molecular transport properties. Therefore, the resin composition of the present invention is generally In the polyvinyl alcohol resin having two or more components as an amorphous structure, By suppressing the molecular mobility of the structure, the component derived from the amorphous structure is reduced to one component. On the other hand, T 1C All resin compositions contain components with a viscosity greater than 50 seconds. This is attributed to the crystalline components of polyvinyl alcohol resins. [Brief description of the drawings]

[0015] [Figure 1] 1 shows T1C (13C spin-lattice relaxation time) measured in Examples 1 and 2 and Comparative Example 1 by solid-state NMR. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] 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.

[0017] The resin composition of the present invention contains a polyvinyl alcohol-based resin. The components contained in the oil composition will be described.

[0018] [Polyvinyl alcohol resin] The polyvinyl alcohol resin used in the present invention (hereinafter, polyvinyl alcohol is referred to as "PVA") ") is usually preferably an unmodified PVA resin, but modified PVA resins are also preferred. It may be used.

[0019] The unmodified PVA resin is usually prepared by polymerizing vinyl ester monomers and then It can be produced by polymerization. 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 means

[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 average degree of saponification is measured according to JIS K 6726. do.

[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 250 to 2,500, and more preferably from 250 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] Among the above PVA-based resins, unmodified PVA is the most suitable because of its excellent oxygen barrier properties under high humidity conditions. PVA resin and modified PVA-based resin are preferred, and unmodified PVA resin is most preferred.

[0028] The PVA-based resin is preferably the main component of the resin composition of the present invention. The content of the PVA resin in the total is usually 80% by weight or more, preferably 90% by weight or more. More preferably, the content is 95% by weight or more, and the upper limit is usually 99.99% by weight.

[0029] [Metal compound] The resin composition of the present invention interacts with the PVA resin, and has a gas barrier property, particularly an oxygen barrier property. In terms of being more excellent in adhesive properties, it is preferable that the composition contains a metal compound. Preferably, the polymer has a structure in which specific structural units are arranged in layers with specific interplanar spacing.

[0030] The structural units are metals, hydroxyl ligands, anionic ligands other than hydroxyl ligands, and is represented by the following chemical formula (2): M a (OH) b A n- (2a-b) / n (2) (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.)

[0031] In the above chemical formula (2), 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 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.

[0032] In the above chemical formula (2), A is, for example, RO (alkoxy ligand), ROCO (Carboxylic Acid Ligand), CO 3 , NO 3 , S.O. 3 , P.O. 4 , B.O. 3 , 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 be a functional group such as an OH group, as long as it does not impair the effect 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. From the viewpoint of interaction, NO 3 , Cl, RO, and ROCO are preferred, and ROCO is particularly preferred. Among them, CH 3 OCO is especially preferred.

[0033] The metal compound used in the present invention may contain water molecules.

[0034] In addition, when the above metal compounds were measured by wide-angle X-ray diffraction using CuKα radiation, the 2θ=2 It is preferable that the main X-ray diffraction peak is at 2θ=2 to 9°. It is preferable that the main peak is at 2θ=3 to 8°, and it is particularly preferable that the main peak is at 2θ=3 to 8°. .

[0035] 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 radiation (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=0~35°, azimuth angle (chi)=-95~-85° ·Azimuth direction one-dimensional: Azimuth angle (chi)=-180~0° When converting the diffraction intensity to one-dimensional in the azimuth 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 azimuth angle of -18 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 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 the range of 2θ = 2 to 15°, it can be judged that a diffraction peak is observed in the range of 2θ = 2 to 15°. Good.

[0036] The interlayer distance (distance between layers) of the above metal compounds is determined by the interaction with the molecules of PVA resin and water molecules. From the viewpoint of interaction, the thickness is preferably 0.01 to 50 nm, and more preferably 0.1 to 30 nm. It is more preferable that the interlayer distance of the metal compound is 2θ=2 to 100 nm when analyzed by X-ray diffraction. Based on the diffraction position of the strongest peak in the range of 15°, the Bragg equation was used to calculate It can be put out.

[0037] The molecular weight of the layered structural unit peeled off from the above metal compound is at the molecular level of the PVA resin. From the viewpoint of enabling interaction, it is preferable that the number is 100 to 10,000, and more preferably 200 to 2 It is particularly preferred that the number is 1,000.

[0038] In addition, the layered structural unit is hydrophilic in terms of interaction with the PVA-based resin molecules. It is preferred. Furthermore, the layered structural unit was left to stand for 1,000 hours in an environment of 20°C and 90% RH. It is preferable that the polymer does not decompose even if it is heated.

[0039] A specific example of the metal compound is a layered compound containing Zn as a metal species. Among them, the chemical formula [Zn 5 (O H) 8 (CH 3 CO 2 ) 2 2H 2 O] is preferred.

[0040] In the present invention, the metal compound and the PVA resin interact with each other to increase the polarity of the PVA resin. By increasing the oxygen barrier property under high humidity, it is possible to obtain an effect of improving the oxygen barrier property under high humidity. It is speculated.

[0041] The metal content of the metal compound in the resin composition is based on 100 parts by weight of the PVA resin. The amount is usually 0.01 to 10 parts by weight, preferably 0.1 to 8 parts by weight, and particularly preferably 0. If the metal compound content is too low, oxygen barrier properties may be impaired under high humidity conditions. If the content of metal compounds is too high, the adhesiveness tends to decrease when it is made into a film, etc. It tends to become white 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 taken as the content. The content of the above metal compounds is determined by the standard addition method using ICP-MS. can be done.

[0042] The above metal compounds can be prepared, for example, by (I) reacting a metal-containing compound in the presence of a base; It can be obtained by a method of heating a metal-containing compound to cause a reaction, or the like.

[0043] Examples of the metal-containing compound used in each of the above methods include organic acid metal salts, inorganic metal salts, etc. Examples include:

[0044] Examples of the organic acid constituting the organic acid metal salt include monovalent carboxylic acids such as acetic acid, cobalt, etc. Dicarboxylic acids such as cisic acid, oxalic acid, tartaric acid, citric acid, ethylenediaminetetraacetic acid, etc. These may be used alone or in combination of two or more. In addition, the organic acid metal salt may be a hydrate or an anhydride. As the organic acid metal salt, monovalent carbohydrates are preferred because of their excellent oxygen barrier properties under high humidity conditions. Metal phosphates are preferred, metal acetates are particularly preferred, and zinc acetate or is its hydrate.

[0045] Examples of the inorganic metal salt 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., which have excellent oxygen barrier properties under high humidity conditions, are preferred. Oxoacids are preferred, and zinc chloride, zinc nitrate, or hydrates thereof are particularly preferred. Each method will be described in detail below.

[0046] The metal compound can be prepared by, for example, (I) converting the metal-containing compound into a salt. (II) a method of reacting a metal-containing compound under heating, etc. This can be done. Each method will be described in detail below.

[0047] [Method (I)] The above method (I) is a method in which a metal-containing compound is reacted in the presence of a base.

[0048] The base used in the above method (I) is, for example, an alkali metal or alkaline earth metal. Among them, the hydroxides of metals are preferred because of their excellent reactivity with metal-containing compounds. Alkali metal hydroxides are preferred, with sodium hydroxide being particularly preferred.

[0049] In the reaction of the metal-containing compound with a base, the metal-containing compound and a salt are usually reacted in a solution. The group may be mixed and reacted. 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 can be mentioned. Among them, 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 preferably used. A method of mixing the metal-containing compound with an organic acid metal salt is preferred. In this case, a solution containing a dissolved base and a solution containing a dissolved organic acid metal salt are added 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 method in which the solution is added and mixed is preferred.

[0050] 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 is no particular limitation as long as it can be dissolved, and examples thereof include water, methanol, ethanol, 1-propanol, etc. 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.

[0051] 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, and 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 does not proceed sufficiently. In addition, if the concentrations of the metal-containing compound and the base are higher than the above ranges, side reactions tend to occur. tends to occur.

[0052] The molar ratio of the metal-containing compound to the base (metal-containing compound:base) is usually 0.5:2. 0.8:1.5 to 1.5:0.8, and particularly preferably If the molar ratio is outside the above range, the reaction does not proceed sufficiently. There is a tendency that

[0053] 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 higher than the above range, 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 adjusting the amount of the solution used.

[0054] 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 will not proceed sufficiently, and if the reaction temperature is too high, the metal The compound contained therein tends to decompose due to heat, making it difficult to obtain the desired metal compound. The reaction time is usually 0.5 to 5 hours, preferably 1 to 3 hours, and the reaction pressure is may be carried out at normal pressure.

[0055] After the above reaction, the metal compound is obtained as a precipitate. The obtained metal compound can be used as it is. However, it is preferable to purify the metal compound by washing, crushing, or the like before use.

[0056] [Method (II)] The above method (II) is a method in which a metal-containing compound is reacted by heating.

[0057] The above method (II) usually involves heating a solution in which a metal-containing compound is dissolved while stirring. This is done by:

[0058] 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, and water is particularly preferred.

[0059] 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 the reaction 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, and particularly preferably The reaction time is preferably 1 to 10 hours, and the reaction pressure may be normal pressure.

[0060] After the above reaction, the metal compound is obtained as a precipitate. The obtained metal compound can be used as it is. Alternatively, the metal compound may be purified by washing, pulverization, or the like before use.

[0061] In general, metal compounds include, for example, metal salts, metal oxides, metal complexes, metal elements or mixtures. However, the metal compounds obtained by the above methods are, as described above, A metal having a layered structure in which the layered structural units represented by formula (1) are arranged at a specific interplanar spacing. It is a layered compound. Therefore, PVA resin molecules and water molecules exist around the metal compound. In this case, the layers of the metal compound are peeled off, and the peeled fine layered structural units are converted into PVA-based It is speculated that excellent oxygen barrier properties are achieved as a result of interaction with the resin at the molecular level. .

[0062] [Other ingredients] The resin composition of the present invention generally contains a resin composition having a resin composition other than that described above, as long as the effect of the present invention is not impaired. Additives to be added to the product, such as heat stabilizers, antioxidants, antistatic agents, colorants, and ultraviolet absorbing agents 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.

[0063] The resin composition of the present invention is preferably a PVA-based resin to which a metal compound is added, and further, if necessary, If necessary, other components may be mixed to obtain the desired composition.

[0064] <Resin composition> The resin composition of the present invention contains a PVA-based resin, and when the resin composition is made into a film, Oxygen permeability (cc 3μm / m 2 ·day·atm) It satisfies the following formula (1). Oxygen permeability (cc 3μm / m 2 ·day·atm)≦80 ···(1)

[0065] The oxygen permeability is 80cc·3μm / m 2 ·day·atm or less is required The preferred value is 70cc 3μm / m 2 ·day·atm or less, preferably 55c c 3μm / m 2 ·day·atm or less, more preferably 30cc·3μm / m 2 ·da y·atm or less, and 20cc·3μm / m is particularly preferable. 2 ·day · atm or less, Particularly preferably, 15cc·3μm / m 2 ·day·atm or less, especially preferred is 10cc·3μm / m 2 ·day·atm or less, most preferably 5cc·3μm / m 2 · The lower limit of oxygen permeability is usually 0cc 3μm / m 2 d ay·atm. In the present invention, the oxygen permeability can be determined by an oxygen permeability measuring device. .

[0066] The resin composition of the present invention contains the PVA resin, and is subjected to solid-state NMR measurement under the following conditions. When this was done, the T of methylene carbon (44-46 ppm) 1c ( 13 C spin-lattice relaxation time) is 2 It is characterized by being composed of components, one of which is 50 seconds or less.

[0067] The solid-state NMR measurement conditions were as follows: the resin composition was filled in a 4 mmφ zirconia rotor. Then, measurements are performed under a static magnetic field of 9.4 T. In addition, the resin composition used for solid-state NMR measurements is The resin composition is not particularly limited as long as it is a solid resin composition, but a film-like resin composition described later is also suitable. It is preferable to use [Solid state NMR measurement conditions] Measurement temperature: 23℃ Sample tube rotation speed: 5,000Hz Observed kernel / decoupling kernel: 13 C(100.7MHz) / 1 H(400.3MHz) Pulse sequence: Inversion Recovery 1 H90° Pulse: 4.2μs×1.6dB(54W / 300W) 13 C90° Pulse: 4.2μs×1.6dB(103W / 500W) Contact time: 350μs Delay time τ: 0.05 to 1,000 s Pulse Delay: 60s Decoupling sequence: TPPM15 Decoupled power: 60kHz (54W / 300W) Accumulation count: 64

[0068] Above T 1c The horizontal axis represents the delay time τ (s) and the vertical axis represents the 44–4 The height of the peak at 6 ppm (the methylene carbon that is the main chain of PVA resin) is plotted on the vertical axis. , Curve fitting is performed according to the following formula (3), and the T 1c By separating Required.

number

[0069] T calculated by the above formula (3) 1c This makes it possible to know the crystalline state of the resin composition. , 50s <T 1c The component with T 1c Components with a value of ≦50s represent an amorphous structure. That is, the resin composition of the present invention has only one amorphous structure as an amorphous structure. Also, T 1c Among the components with a value of ≦50s, those with a value of 20s <T 1c The components that are ≦50s are motion The amorphous structure is easy to dissolve, 1c Components with a value of ≦20s represent amorphous structures that are difficult to move. The structure is T 1c The fact that the film has only an amorphous structure that is difficult to move and has a viscosity of 20 seconds or less under high humidity conditions This is preferred from the viewpoint of excellent oxygen barrier properties. Generally, the gas barrier properties of crystalline polymers such as PVA resins are largely determined by the amorphous structure. Therefore, the present invention suppresses the molecular motion of the amorphous structure portion, thereby preventing the crystallization under high humidity conditions. This provides the effect of providing excellent oxygen barrier properties.

[0070] In the present invention, the T 1c of 50 The components below seconds are T 1c It is preferable that the ratio is 20% or more, and more preferably 25% or more. Particularly preferably, it is at least 30%. The upper limit is usually 50%.

[0071] In the present invention, the molecular mobility of the amorphous structure of the PVA resin is suppressed, Formula (1) and the above T 1c Since it satisfies the above conditions, it has a gas barrier effect under high humidity. In order to obtain such a resin composition, for example, Examples of the method include a method of placing an object under high humidity. Among these methods, a method of placing a film containing a resin composition A method of leaving the material to stand under high humidity is preferred.

[0072] <Film Containing Resin Composition> The film containing the resin composition of the present invention is formed by forming a composition containing the resin composition. The resin composition is preferably formed into a film. It is possible to do so.

[0073] The film can be formed, for example, by dissolving a solution or dispersion (copolymer) of the resin composition in water. A method using a coating liquid, a pellet-shaped composition containing the resin composition of the present invention, Among them, the method of melt molding using a solution or a dispersion machine of the resin composition is particularly preferred. A method using a spray liquid (coating liquid) is preferred. In addition, when using the above coating liquid, In this case, the solid content is usually 0.5 to 30% by weight, and preferably 5 to 20% by weight.

[0074] The coating solution can be prepared, for example, by mixing all the components in a solvent at once. 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 PVA resin is dissolved in a solvent. The preferred method is to add and mix the components. In the method for obtaining the metal compound, the metal-containing compound is reacted in the presence of a solvent. It is also preferable to dissolve a PVA-based resin in the mixture, and from the viewpoint of workability, it is particularly preferable to use the above-mentioned (II). This is preferred when a metal compound is obtained by the method. As the solvent, the solvents listed for the metal compound can be used, and among them, water is preferred. I wish.

[0075] Examples of the film-forming method include a melt extrusion method, an endless belt method, a drum method, and a coating method. In particular, known methods such as a method using a casting method can be used. The method is preferred, and the coating method is particularly preferred.

[0076] Examples of the coating method include bar coating, roll coating, die coating, etc. Examples of the coating method include known methods such as coating, gravure coating, comma coating, and screen printing. can be.

[0077] After coating, the coating is dried by heating at 60 to 105°C for 0.5 to 10 minutes. In this way, a film made of the resin composition can be obtained. Depending on the circumstances, a stretching operation such as uniaxial stretching or biaxial stretching may be carried out.

[0078] 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.

[0079] 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 more preferably from 1 to 50 μm. In the case of a structure, the total thickness of all films containing the resin composition is taken as the film thickness. The thickness of the film.

[0080] 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 Examples of the polyolefins include substituted polyolefins, aromatic and aliphatic polyketones. These base resins may be used alone or in combination of two or more. Surface treatment may also be performed.

[0081] As described above, by leaving the film containing the resin composition of the present invention under high humidity, The film is represented by the formula (1) and the T 1c Since the condition of high humidity is met, The gas barrier properties, especially the oxygen barrier properties, are excellent at low temperatures. Although the mechanism is unclear, polyvinyl alcohol resin may become unstable when left in a high humidity environment. The molecules of the film are plasticized, and the metal compounds dispersed in the film are transferred to the polyvinyl alcohol resin. It is speculated that this is due to interaction with the fat or localization at the surface of the film.

[0082] 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.

[0083] 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 (%).

[0084] The resin composition of the present invention and a film made of the resin composition are useful as packaging materials. It can be particularly suitably used as a packaging material for food, medicines, etc. EXAMPLES

[0085] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the description of the examples. In the examples, "parts" and "%" are by weight unless otherwise specified.

[0086] Prior to the examples, the following polyvinyl alcohol-based resins were prepared.

[0087] [Polyvinyl alcohol resin] [PVA resin] PVA (unmodified PVA resin, average degree of polymerization 300, average degree of saponification 99 mol%)

[0088] <Example 1> 900 parts of water, 100 parts of PVA, Zn(CH 3 COO) 2 2H 2 0.3 parts of O in terms of metal was added, and the mixture was heated and stirred at 90°C for 3 hours to form a resin composition (coating). The obtained coating solution was applied to a 38 μm-thick PE Apply to the corona-treated surface of the substrate using wire bar #18 and dry at 80°C for 5 minutes. A two-layer film in which a film layer made of a resin composition having a thickness of 3 μm is laminated on a PET substrate. The obtained film was left to stand under the humidity control conditions of 23°C and 80% RH for 200 hours. A room was prepared.

[0089] <Example 2> In Example 1, the added Zn(CH 3 COO) 2 2H 2 The amount of O is 100 parts PVA A film was prepared in the same manner as in Example 1, except that the amount of the metal was changed to 1 part per 100 parts. The samples were prepared under the same humidity control conditions.

[0090] <Comparative Example 1> In Example 1, Zn(CH 3 COO) 2 2H 2 Except for the absence of O, A film was prepared in the same manner as in Example 1 and under the same humidity control conditions.

[0091] [Wide-angle X-ray diffraction (XRD) measurement] The films obtained in Examples 1 and 2 and Comparative Example 1 were analyzed by wide-angle X-ray diffraction (X RD) measurements were performed. [Measurement conditions] Equipment used: D8 DISCOVER (manufactured by Bruker Japan) Voltage: 50kV Current: 100mA Camera length: 150mm Measurement method: Reflection method Accumulation time: 20 minutes

[0092] As a result of the measurement, the films of Examples 1 and 2 had 2θ=6.8°, 13.5°, and 20.2°. The main peak was detected. These are shown in Inorg.Chem.2013,52,95-10. Since the compound coincided with the Zn-containing layered compound described in Example 2, it was found that the compound was not included in the films of Examples 1 and 2. The metal compounds that can be used are Zn-containing layered compounds [Zn 5 (OH) 8 (CH 3 CO 2 ) 2 2H 2 Same as O It was determined. In addition, when the films of Examples 1 and 2 were measured by wide-angle X-ray diffraction, Based on the diffraction position at 2θ=6.8°, the interlayer distance was calculated from the Bragg equation. The Zn-containing layered compound [Zn 5 (OH) 8 (CH 3 CO 2 ) 2 2H 2 O] has a layer spacing of 1.3 It was a layered compound of nm. On the other hand, in the film of Comparative Example 1, the main peak detected in the films of Examples 1 and 2 was not detected. It was not done.

[0093] <Oxygen barrier properties> From the two-layer films of the examples and comparative examples obtained above, a film made of a resin composition The layer was removed and the oxygen permeability of the removed film layer was measured using an oxygen permeability measuring device (OX-TR The measurements were taken using a meter (AN100A, manufactured by MOCON) at 23°C and 80% RH. The results are shown in Table 1 below.

[0094] <Solid state NMR measurement> From the two-layer films of the examples and comparative examples obtained above, a film made of a resin composition The layer was taken out and cut with scissors into pieces measuring 1 to 3 mm on each side. After filling the mixture in a Conia rotor, the solid-state NMR was used to measure the amount of the mixture in a static magnetic field of 9.4 T ( 1 H: Resonance frequency 4 00MHz, 13C: Resonance frequency 100MHz) 23℃, magic angle spinning condition Rotate at 5000Hz and 1C ( 13 C nuclear spin-lattice relaxation times were measured. From the obtained spectrum, the delay time τ (s) is plotted on the horizontal axis, and the 70 ppm ( The peak height of the methylene carbon of the main chain of the PVA-based resin was plotted on the vertical axis, and the following formula (3 ) and perform curve fitting using Microsoft Excel solver. T 1C Each component was separated.

number

[0095] [Table 1]

[0096] As can be seen from Table 1 above, the films of Examples 1 and 2 had an oxygen permeability of 80cc / 3 μm / m 2 The oxygen barrier properties of Comparative Example 1 were excellent. The film has an oxygen permeability of 100cc·3μm / m 2 ·day·atm, oxygen balance It was inferior in quality.

[0097] Furthermore, when solid-state NMR was measured, T 1c It consists of two components, one of which is less than 50 seconds. The films of Examples 1 and 2 of Tsunomi were excellent in oxygen barrier properties under high humidity conditions. On the other hand, T 1c The film of Comparative Example 1, which is made up of three components and has two components with a melting time of 50 seconds or less, However, the oxygen barrier properties under high humidity conditions were poor. [Industrial Applicability]

[0098] The resin composition of the present invention has excellent oxygen barrier properties under high humidity conditions, and is therefore useful as a packaging material. It is particularly useful as a packaging material for food, medicines, etc.

Claims

1. A resin composition containing a polyvinyl alcohol resin, the resin composition being formed into a film. The oxygen permeability (cc 3 μm / m) under a 23°C, 80% RH environment 2 ・day・a tm) satisfies the following formula (1): Oxygen permeability (cc・3μm / m 2 ・dayatm)≦80・・・(1)

2. A resin composition containing a polyvinyl alcohol resin, the resin composition being subjected to the following conditions: When solid-state NMR was measured, the T 1C ( 13 C spin - case A resin composition comprising two components, one of which has a molecular relaxation time of 50 seconds or less. Composition. conditions: The resin composition was filled into a 4 mmφ zirconia rotor, and then subjected to static NMR at 9.4 T using a solid-state NMR. Under magnetic field ( 1 H: resonance frequency 400MHz, 13 C: Resonance frequency 100MHz) 23℃, seriously The sample is rotated at 5,000 Hz under double angle spinning conditions.

3. The above T 1c The components below 50 seconds are T 1c 2. The method according to claim 1, wherein the ratio of the thickness of the first electrode to the thickness of the second electrode is 20% or more. The resin composition described above.

4. The polyvinyl alcohol further contains a metal compound, and the metal content of the metal compound is The content of the binder resin is 0.01 to 10 parts by weight based on 100 parts by weight of the base resin.

4. The resin composition according to any one of claims 3 to 4.

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

6. The oxygen permeability of the above film under an environment of 23°C and 80% RH is 80cc.3μm / m 2 6. The film according to claim 5, characterized in that it has a viscosity of not more than 1000 sq. day atm.

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

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