Metallized film, multilayer structure, molded article, food container, and method for manufacturing a metallized film.

Abstract

To provide a vapor-deposited film with excellent surface smoothness of the vapor-deposited surface. [Solution] A vapor-deposited film comprising a base film having a layer containing a composition comprising an ethylene-vinyl alcohol copolymer, a compound having a conjugated polyene structure, and a titanium compound, and a metal vapor-deposited layer laminated on the base film, wherein the metal equivalent content of the titanium compound is 0.001 ppm or more and less than 3 ppm relative to the mass of the composition.

Description

Technical Field

[0001] The present invention relates to a vapor deposition film, a multilayer structure, a molded body, a food container, and a method for manufacturing a vapor deposition film. More specifically, it relates to a vapor deposition film, a multilayer structure, a molded body, a food container, and a method for manufacturing a vapor deposition film that are excellent in surface smoothness.

Background Art

[0002] Ethylene-vinyl alcohol copolymer (hereinafter sometimes referred to as "EVOH resin") has very strong intermolecular forces due to hydrogen bonding between hydroxyl groups present in the polymer side chains. Therefore, it has high crystallinity and high intermolecular forces even in the amorphous part. Thus, a film using EVOH resin is difficult for gas molecules etc. to pass through and exhibits excellent gas barrier properties. Therefore, EVOH resin is used as a gas barrier layer for imparting gas barrier properties to multilayer structures such as films and containers in a wide range of fields such as food packaging.

[0003] Also, conventionally, aluminum foil has been mainly used as a gas barrier material under high humidity conditions. However, since aluminum has a high thermal conductivity and is inferior in heat insulation performance etc., a high gas barrier film having a thin metal vapor deposition layer has been studied as an alternative to aluminum foil.

[0004] For example, in Patent Documents 1 and 2, as a vapor deposition film capable of suppressing the generation of pinholes and cracks during vapor deposition film processing such as lamination and suppressing a decrease in gas barrier properties, a substrate film containing EVOH resin is provided with a metal vapor deposition layer, and a vapor deposition film having an average particle size of such a metal vapor deposition layer within a specific range is disclosed. In such a technique, it is described that the EVOH resin may contain 0.001 to 1% by mass (equivalent to 10 to 10000 ppm in terms of conversion) of an inorganic oxide (Patent Documents 1 and 2: Paragraphs

[0017] ,

[0018] ).

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2017-100451 [Patent Document 2] International Publication No. 2013 / 125564 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, Patent Documents 1 and 2 do not consider the surface smoothness of the vapor-deposited film, and there is a risk that minute irregularities may occur on the surface of the vapor-deposited film. A vapor-deposited film with excellent surface smoothness can suppress stress concentration due to external stress during transportation, prevent the occurrence of cracks, suppress the deterioration of gas barrier properties, and maintain stable performance over a long period of time. Therefore, there was room to improve the surface smoothness of the vapor-deposited films in Patent Documents 1 and 2.

[0007] This invention has been made in view of the above problems, and aims to provide a vapor-deposited film with excellent surface smoothness of the vapor-deposited surface, a multilayer structure containing the same, a molded article, a food container, and a method for manufacturing a vapor-deposited film. [Means for solving the problem]

[0008] However, in view of these circumstances, the inventors conducted extensive research and found that by adding a compound having a conjugated polyene structure and a specific trace amount of titanium compound to the EVOH resin in the base film, the surface smoothness of the vapor-deposited surface of the resulting vapor-deposited film becomes smoother.

[0009] In other words, the present invention has the following aspects. [1] A vapor-deposited film comprising a base film having a layer containing a composition comprising an ethylene-vinyl alcohol copolymer, a compound having a conjugated polyene structure, and a titanium compound, and a metal vapor-deposited layer laminated on the base film, wherein the metal equivalent content of the titanium compound is 0.001 ppm or more and less than 3 ppm relative to the mass of the composition. [2] The vapor-deposited film according to [1], wherein the content of the compound having the conjugated polyene structure is 1 to 3000 ppm relative to the mass of the composition. [3] The vapor-deposited film according to [1] or [2], wherein the mass ratio of the content of the compound having the conjugated polyene structure to the metal equivalent content of the titanium compound is 0.3 to 1,000,000. [4] The vapor-deposited film according to any one of [1] to [3], wherein the base film is a multilayer film further having a layer containing a thermoplastic resin. [5] The vapor-deposited film according to any one of [1] to [4], wherein the metal of the metal vapor-deposited layer is at least one selected from the group consisting of aluminum, gold, silver, copper, titanium, nickel, chromium, tin, and indium. [6] A multilayer structure comprising a vapor-deposited film as described in any of [1] to [5]. [7] A molded article comprising a vapor-deposited film as described in any of [1] to [5]. [8] [6] A food container comprising the multilayer structure described above. [9] A method for manufacturing a vapor-deposited film according to any one of [1] to [5], comprising the step of laminating a metal vapor-deposited layer onto the base film. [Effects of the Invention]

[0010] The vapor-deposited film of the present invention exhibits excellent surface smoothness of the vapor-deposited surface. Furthermore, multilayer structures, molded articles, and food containers containing such vapor-deposited film also exhibit excellent surface smoothness of the vapor-deposited surface.

Mode for Carrying Out the Invention

[0011] The present invention will be described below based on examples of embodiments for carrying out the present invention. However, the present invention is not limited to the embodiments described below. In this specification, when expressed as "X to Y" (X and Y are arbitrary numbers), unless otherwise specified, it means "X or more and Y or less" and also includes the meaning of "preferably exceeding X" or "preferably less than Y". When expressed as "X or more" (X is an arbitrary number) or "Y or less" (Y is an arbitrary number), it also includes the meaning of "preferably exceeding X" or "preferably less than Y". In addition, "x and / or y" (x and y are arbitrary components) means at least one of x and y, and includes three cases: only x, only y, and x and y. Regarding the numerical ranges described stepwise in this specification, the upper limit value or lower limit value of the numerical range at a certain step can be arbitrarily combined with the upper limit value or lower limit value of the numerical range at other steps. Also, in the numerical ranges described in this specification, the upper limit value or lower limit value of the numerical range can be replaced with the value shown in the examples.

[0012] In this specification, "film" includes "tape" and "sheet".

[0013] Hereinafter, when the monomer units contained in EVOH resin or thermoplastic resin are simply referred to as "units", for example, the monomer unit based on ethylene may be referred to as "ethylene unit".

[0014] <<Evaporation Film>> The evaporation film which is one embodiment of the present invention (hereinafter sometimes referred to as "this evaporation film") includes a base film and a metal evaporation layer laminated on the base film. Each component will be described below.

[0015] <Base Film> The base film has a layer containing an EVOH resin, a compound having a conjugated polyene structure, and a titanium compound (hereinafter referred to as the "EVOH layer"). Hereinafter, each component of the base film will be described.

[0016] [EVOH layer] The EVOH layer is formed from a composition containing an EVOH resin, a compound having a conjugated polyene structure, and a titanium compound (hereinafter sometimes referred to as "this composition"). This composition will be described below.

[0017] This composition has an EVOH resin as the main component and contains a compound having a conjugated polyene structure and a specific trace amount of a titanium compound. That is, in this composition, the base resin is an EVOH resin, and the content of the EVOH resin in this composition is usually 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more. Hereinafter, each component will be described.

[0018] (EVOH resin) The EVOH resin used in this embodiment is usually a resin obtained by saponifying an ethylene-vinyl ester copolymer, which is a copolymer of ethylene and a vinyl ester monomer, and is a water-insoluble thermoplastic resin.

[0019] [[ID=2**6]]As the vinyl ester monomer, vinyl acetate is typically used from the viewpoints of good market availability and efficient impurity treatment during production. Examples of other vinyl ester monomers other than vinyl acetate include aliphatic vinyl esters such as vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprinate, vinyl laurate, vinyl stearate, vinyl versatate, and aromatic vinyl esters such as vinyl benzoate. Usually, aliphatic vinyl esters having 3 to 20 carbon atoms, preferably 4 to 10 carbon atoms, and particularly preferably 4 to 7 carbon atoms are used. These are usually used alone, but a plurality of types may be used simultaneously if necessary.

[0020] The polymerization method for copolymerizing the ethylene and vinyl ester monomer can be any known polymerization method, such as solution polymerization, suspension polymerization, or emulsion polymerization, but generally, solution polymerization using methanol as the solvent is used. Furthermore, the saponification of the obtained ethylene-vinyl ester copolymer can also be carried out by known methods. The EVOH resin produced in this manner mainly consists of ethylene-derived structural units and vinyl alcohol structural units, and contains a small amount of vinyl ester structural units that remain unsaponified.

[0021] The ethylene structural unit content in the EVOH resin is typically 20 to 60 mol%, preferably 25 to 50 mol%, and particularly preferably 25 to 35 mol%. The ethylene structural unit content can be controlled by the pressure of the ethylene when copolymerizing the vinyl ester monomer and ethylene. When the content is above the lower limit, the resin tends to exhibit excellent gas barrier properties and melt moldability under high humidity conditions, while when it is below the upper limit, the resin tends to exhibit excellent gas barrier properties. The content of such ethylene structural units can be measured in accordance with ISO 14663.

[0022] The degree of saponification in the EVOH resin is typically 90-100 mol%, preferably 95-100 mol%, and particularly preferably 99-100 mol%. The degree of saponification can be controlled by the amount of saponification catalyst (usually an alkaline catalyst such as sodium hydroxide) used to saponify the ethylene-vinyl ester copolymer, the temperature, the time, etc. When the degree of saponification is above the lower limit, the resin tends to exhibit excellent gas barrier properties, thermal stability, moisture resistance, etc. The degree of saponification of such EVOH resin can be measured according to JIS K6726 (provided that the EVOH resin is used as a solution uniformly dissolved in water / methanol solvent).

[0023] The melt flow rate (MFR) (210°C, 2160g load) of the EVOH resin is typically 0.5 to 100 g / 10 min, preferably 1 to 50 g / 10 min, and particularly preferably 3 to 35 g / 10 min. When the MFR is below the upper limit, the film tends to be stable, and when it is above the lower limit, it tends to have an appropriate viscosity and facilitate melt extrusion. The aforementioned MFR is an indicator of the degree of polymerization of the EVOH resin and can be adjusted by the amount of polymerization initiator and solvent used when copolymerizing ethylene and vinyl ester monomers. In this specification, MFR can be determined by measuring the rate at which the sample flows out through an orifice with a length of 8 mm and a hole diameter of 2.095 mm, using an automated melt flow rate tester (manufactured by Toyo Seiki Co., Ltd.) under conditions of a temperature of 210°C and a load of 2160 g.

[0024] Furthermore, the EVOH resin may contain structural units derived from the following comonomers, to the extent that they do not impede the effects of the present invention (for example, 10 mol% or less of the EVOH resin). Examples of the comonomers include olefins such as propylene, 1-butene, and isobutene; hydroxyl group-containing α-olefins such as 3-buten-1-ol, 3-buten-1,2-diol, 4-penten-1-ol, and 5-hexen-1,2-diol, and their esterified and acylated derivatives; hydroxyalkylvinylidenes such as 2-methylenepropane-1,3-diol and 3-methylenepentane-1,5-diol; 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane, and 1,3-dibuty Hydroxyalkylvinylidene diacetates such as lyloxy-2-methylenepropane; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, (anhydride) phthalic acid, (anhydride) maleic acid, (anhydride) itaconic acid, or their salts, or mono or dialkyl esters with 1 to 18 carbon atoms in the alkyl group; acrylamide, N-alkylacrylamide with 1 to 18 carbon atoms in the alkyl group, N,N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid, or their salts, acrylamidopropyldimethylamine, or its salts, or its quaternary salts Acrylamides such as methacrylamide, N-alkylmethacrylamide with 1 to 18 C1 of the alkyl group, N,N-dimethylmethacrylamide, 2-methacrylamidepropanesulfonic acid or its salts, methacrylamidopropyldimethylamine or its salts or its quaternary salts, etc.; N-vinylamides such as N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, etc.; vinyl cyanides such as acrylonitrile, methacrylnitrile, etc.; alkyl vinyl ethers with 1 to 18 C1 of the alkyl group, hydro Examples include vinyl ethers such as xyalkyl vinyl ethers and alkoxyalkyl vinyl ethers; vinyl halogenated compounds such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, and vinyl bromide; vinyl silanes such as trimethoxyvinylsilane; allyl halogenated compounds such as allyl acetate and allyl chloride; allyl alcohols such as allyl alcohol and dimethoxyallyl alcohol; and comonomers such as trimethyl-(3-acrylamido-3-dimethylpropyl)-ammonium chloride and acrylamide-2-methylpropanesulfonic acid.These can be used individually or in combination of two or more types.

[0025] Among these, hydroxyl group-containing α-olefins are preferred, and 3-butene-1,2-diol and 5-hexene-1,2-diol are particularly preferred. When the hydroxyl group-containing α-olefins are copolymerized, the resulting EVOH resin has primary hydroxyl groups in its side chains. Such EVOH resins having primary hydroxyl groups in their side chains, and especially EVOH resins having a 1,2-diol structure in their side chains, are preferred because they maintain gas barrier properties while exhibiting good secondary moldability.

[0026] When the EVOH resin has a primary hydroxyl group in its side chain, the content of structural units derived from the monomer having the primary hydroxyl group is typically 0.1 to 20 mol%, preferably 0.5 to 15 mol%, and particularly preferably 1 to 10 mol% of the EVOH resin.

[0027] Furthermore, as the EVOH resin, EVOH resins that have undergone "post-modification" such as esterification, urethaneization, acetalization, cyanoethylation, or oxyalkyleneization can also be used.

[0028] When using the post-modified EVOH resin described above, the modification rate is usually 10 mol% or less, preferably 4 mol% or less. When the modification rate of the EVOH resin is below the upper limit, thermal degradation is suppressed, and it tends to have excellent long-run performance.

[0029] Furthermore, the EVOH resin may be a mixture of EVOH resins with different ethylene structural unit content, degree of saponification, degree of polymerization, copolymer components, etc.

[0030] (Compounds having a conjugated polyene structure) The compound having a conjugated polyene structure used in this embodiment is a compound having a structure in which carbon-carbon double bonds and carbon-carbon single bonds are alternately linked, and the number of carbon-carbon double bonds is two or more, in other words, a compound having a so-called conjugated double bond. Compounds having a conjugated polyene structure may be conjugated diene compounds having a structure in which two carbon-carbon double bonds and one carbon-carbon single bond are alternately linked, conjugated triene compounds having a structure in which three carbon-carbon double bonds and two carbon-carbon single bonds are alternately linked, or conjugated polyene compounds having a structure in which a number of carbon-carbon double bonds and carbon-carbon single bonds are alternately linked. However, the compounds having the aforementioned conjugated polyene structure are excluded from aromatic carboxylic acids such as cinnamic acids and quinones such as hydroquinone and benzoquinone.

[0031] Furthermore, when a compound having the conjugated polyene structure has eight or more conjugated carbon-carbon double bonds, there is a concern that the molded product may become discolored due to the color of the conjugated polyene compound itself; therefore, it is preferable that the number of conjugated carbon-carbon double bonds be seven or less. Moreover, a compound having the conjugated polyene structure may have multiple sets of conjugated double bonds consisting of two or more carbon-carbon double bonds that are not conjugated to each other within a single molecule. For example, compounds with three conjugated trienes in the same molecule, such as tung oil, are also included in compounds having the conjugated polyene structure.

[0032] The molecular weight of the compound having the conjugated polyene structure is usually 30 to 500, preferably 50 to 400, and particularly preferably 100 to 300, from the viewpoint of productivity and ease of handling. Furthermore, the number of carbon atoms in one molecule of the compound having the conjugated polyene structure is usually 4 to 30, preferably 4 to 20, and particularly preferably 4 to 10, from the viewpoint of productivity and handling.

[0033] Examples of compounds having such a conjugated polyene structure include isoprene, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-t-butyl-1,3-butadiene, 1,3-pentadiene, 2,3-dimethyl-1,3-pentadiene, 2,4-dimethyl-1,3-pentadiene, 3,4-dimethyl-1,3-pentadiene, 3-ethyl-1,3-pentadiene, and 2-methyl-1,3-pentadiene. 3-methyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, 1,3-hexadiene, 2,4-hexadiene, 2,5-dimethyl-2,4-hexadiene, 1,3-octadiene, 1,3-cyclopentadiene, 1,3-cyclohexadiene, 1-phenyl-1,3-butadiene, 1,4-diphenyl-1,3-butadiene, 1-methoxy-1,3-butadiene, 2-methoxy-1,3-butadiene, 1-ethoxy-1, 3-Butadiene, 2-Ethoxy-1,3-Butadiene, 2-Nitro-1,3-Butadiene, Chloroprene, 1-Chloro-1,3-Butadiene, 1-Bromo-1,3-Butadiene, 2-Bromo-1,3-Butadiene, Fluben, Tropone, Ocimene, Phellandrene, Myrcene, Farnesene, Sembren; Sorbic acid, sorbate esters, sorbates, and other sorbic acids, abietic acid, and other sorbic acids with two carbon-carbon double bonds forming a conjugated structure. Examples include conjugated diene compounds; conjugated triene compounds consisting of a conjugated structure with three carbon-carbon double bonds, such as 1,3,5-hexatriene, 2,4,6-octatriene-1-carboxylic acid, eleostearic acid, tung oil, and cholecalciferol; and compounds having a conjugated polyene structure consisting of a conjugated structure with four or more carbon-carbon double bonds, such as cyclooctatetraene, 2,4,6,8-decatetraene-1-carboxylic acid, retinol, and retinoic acid. For compounds having multiple stereoisomers, such as 1,3-pentadiene, myrcene, and farnesene, any of the stereoisomers may be used. The aforementioned compounds having a conjugated polyene structure may be used alone or in combination of two or more.

[0034] Among these compounds having a conjugated polyene structure, those having a carboxyl group are preferred due to their high affinity for water, and more preferably are chain-like compounds having a carboxyl group, with sorbic acids being particularly preferred, and sorbic acid being especially preferred.

[0035] The content of the compound having the conjugated polyene structure is typically 1 to 3000 ppm, preferably 10 to 1000 ppm, more preferably 50 to 700 ppm, and particularly preferably 70 to 600 ppm, relative to the mass of the composition. When the content of the compound having the conjugated polyene structure is below the upper limit, the composition tends to have excellent thermal stability, and when it is above the lower limit, the composition tends to have excellent moldability.

[0036] The content of the compound having the aforementioned conjugated polyene structure can be measured, for example, using a liquid chromatograph-ultraviolet spectrometer, according to the following procedure. The following procedure is described using sorbic acid as an example, but other compounds having a conjugated polyene structure can be measured using a similar procedure by using an extraction solvent suitable for that compound. [Method for measuring the content of compounds having a conjugated polyene structure] (1) Add 8 mL of extraction solvent (distilled water:methanol = 1:1, volume ratio) to 1 g of powder obtained by freeze-drying the composition. (2) The solution is subjected to sonication at 20°C for 1 hour while standing to extract sorbic acid from the resin, and after cooling, the volume is reduced to 10 mL with the extraction solvent. Dilution to any desired ratio may also be performed as needed. (3) After filtering the solution through a filter with a pore size of 0.45 μm, the sorbic acid content in the extracted solution is measured using a liquid chromatograph-ultraviolet spectrometer. (4) A calibration curve is prepared from the standard solutions of sorbic acid prepared using the extraction solvent described above, and the sorbic acid content is quantified using the absolute calibration curve method. [HPLC measurement conditions] • LC System: Agilent 1260 / 1290 [Manufactured by Agilent Technologies] • Detector: Agilent 1260 Infinity Diode Array Detector [Manufactured by Agilent Technologies] • Column: Cadenza CD-C18 (100 x 3.0 mm, 3 μm) [Imtakt] Column temperature: 40℃ Mobile phase A: 5% acetonitrile aqueous solution containing 0.05% formic acid. Mobile phase B: 95% acetonitrile aqueous solution containing 0.05% formic acid. • Time program: 0.0 → 5.0 minutes B% = 30% 5.0→8.0 minutes B%=30%→50% 8.0→10.0 minutes B%=50% 10.0→13.0 minutes B%=50%→30% 13.0→15.0 minutes B%=30% ·Flow rate: 0.2mL / min UV detection wavelength: 190~400nm ·Quantitation wavelength: 262nm Note that "%" in the HPLC measurement conditions refers to volume percentage. Furthermore, if the amount of compound having a conjugated polyene structure added is known, the added amount may be used as the content.

[0037] The mass ratio of the content of the compound having the conjugated polyene structure to the metal equivalent content of the titanium compound described later is preferably 0.3 to 1,000,000, more preferably 1 to 50,000, and particularly preferably 10 to 2,500. When the mass ratio is within the aforementioned range, there is a tendency for improved thermal stability. Furthermore, when the mass ratio is below the upper limit, there is a tendency for superior thermal stability, and when it is above the lower limit, there is a tendency for superior moldability of the composition.

[0038] Although the reason why the compound having the conjugated polyene structure provides superior effects is not clear, it is presumed that adding an appropriate amount of the compound with the conjugated polyene structure improves thermal stability, suppresses the formation of streaks and microgels, and results in a smoother surface.

[0039] (Titanium compound) Examples of the titanium compounds include inorganic titanium compounds and organic titanium compounds. The titanium compounds may be used individually or in combination of two or more. Inorganic titanium compounds are preferred.

[0040] Examples of the inorganic titanium compound include titanium oxide, titanium hydroxide, titanium chloride, and inorganic salts of titanium. Examples of the aforementioned titanium oxides include titanium(II) oxide, titanium(III) oxide, titanium(IV) oxide, and titanium dioxide. Examples of the aforementioned titanium hydroxides include titanium 1 hydroxide and titanium 2 hydroxide. Examples of the aforementioned titanium chlorides include titanium chloride, titanium chloride, and the like. The inorganic salts of titanium mentioned above are those other than titanium chlorides, and include, for example, titanium phosphate and titanium sulfate. Of these, titanium oxide is preferred, titanium(IV) oxide is more preferred, and rutile-type titanium(IV) oxide is particularly preferred.

[0041] Examples of the aforementioned organic titanium compounds include titanium acetate, titanium butyrate, titanium carboxylate such as titanium stearate, and others.

[0042] In addition to existing as a titanium compound in this composition, the titanium compound may also exist in an ionized state or as a complex interacting with EVOH resin or other ligands.

[0043] The average particle size of the titanium compound is typically 0.001 to 100 μm, preferably 0.01 to 50 μm, and more preferably 0.015 to 20 μm. When the average particle size of the titanium compound is within this range, it tends to exhibit excellent surface roughness suppression. The average particle size of the titanium compound can be measured using a laser diffraction particle size distribution analyzer or the like. The average particle size referred to here is the median diameter.

[0044] The metallic content of the titanium compound is 0.001 ppm or more and less than 3 ppm relative to the mass of the composition. Preferably, it is 0.01 to 1 ppm, more preferably 0.03 to 0.5 ppm, and particularly preferably 0.05 to 0.2 ppm. By setting the titanium compound content within this range, the titanium compound fills in minute depressions on the surface of the EVOH film, resulting in excellent surface smoothness. Note that the metallic content of a titanium compound refers to the content of the element titanium.

[0045] By setting the metal equivalent content of the titanium compound within the aforementioned range, the formation of microgels due to thermal degradation during melt molding is suppressed, and the titanium compound tends to fill in minute depressions on the surface of the EVOH resin layer, resulting in superior film surface smoothness. Conversely, if the metal equivalent content of the titanium compound is too low, the effect of suppressing the formation of microgels decreases, and the titanium compound cannot fill in minute depressions on the surface of the EVOH resin layer, leading to a decrease in surface smoothness. If the metal equivalent content is too high, thermal decomposition of the EVOH resin is more likely to occur, leading to the formation of microgels, and the appearance of the titanium compound on the surface of the EVOH resin layer tends to create protrusions, resulting in a decrease in surface smoothness.

[0046] The metallic content of the titanium compound can be quantified by weighing the composition into a platinum crucible, sequentially ashing it with a burner and an electric furnace, thermally decomposing the ashed material with nitric acid and hydrofluoric acid, treating it with a mixed acid of dilute nitric acid and dilute hydrofluoric acid to obtain a fixed-volume solution, and measuring the titanium in the solution using an ICP mass spectrometer (Agilent 8800, manufactured by Agilent Technologies). Furthermore, if the amount of titanium compound added is known, that amount may be used as the content.

[0047] Normally, when a titanium compound is included in a composition containing EVOH resin, it is considered common technical practice for manufacturers to avoid using titanium compounds because the titanium ions cause thermal degradation of the composition and generate microgels. However, in this embodiment, contrary to this common technical practice, we have found that when a specific trace amount of titanium compound is used, the titanium in the titanium compound coordinates to the double bonds of the main chain of the EVOH resin, forming chelates, thereby improving thermal stability, suppressing the formation of microgels due to thermal degradation, and resulting in an EVOH film with excellent surface smoothness.

[0048] Furthermore, EVOH resin discolors due to thermal degradation. This is presumed to be because heat degrades the EVOH resin, generating radicals. These radicals dehydrate the hydroxyl groups in the EVOH resin, creating double bonds in the main chain of the EVOH resin. These sites act as reaction initiation points, further accelerating dehydration and forming a conjugated polyene structure in the main chain of the EVOH resin. In this composition, however, the titanium in the specific trace amount of titanium compound is stable as a tetravalent ion. Therefore, even in trace amounts, it is presumed to stabilize the EVOH resin by coordinating with the double bonds in the main chain and forming chelates, thereby suppressing the formation of the polyene structure.

[0049] (Other combination drugs) Furthermore, the composition may contain compounding agents (excluding titanium compounds) that are generally incorporated into EVOH resins, within a range that does not impair the effects of the present invention (for example, usually 30% by mass or less of the composition, preferably 20% by mass or less, more preferably 10% by mass or less, with the lower limit usually being 0% by mass). Examples of such compounding agents include inorganic double salts (e.g., hydrotalcite), plasticizers (e.g., ethylene glycol, glycerin, aliphatic polyhydric alcohols such as hexanediol), oxygen absorbers (e.g., inorganic oxygen absorbers such as aluminum powder and potassium sulfite; ascorbic acid, and further its fatty acid esters and metal salts, etc.), polyhydric phenols such as gallic acid and hydroxyl group-containing phenol aldehyde resins, terpene compounds, blends of tertiary hydrogen-containing resins and transition metals (e.g., combinations of polypropylene and cobalt), and carbon-carbon unsaturated bond-containing resins and transition metals. Blends with transfer metals (e.g., a combination of polybutadiene and cobalt), photo-oxidative degradable resins (e.g., polyketones), anthraquinone polymers (e.g., polyvinylanthraquinone), and polymeric oxygen absorbers such as those obtained by adding photoinitiators (e.g., benzophenone), antioxidants or deodorants other than those mentioned above (e.g., activated carbon), heat stabilizers, light stabilizers, ultraviolet absorbers, colorants, antistatic agents, surfactants (except those used as lubricants), antibacterial agents, antiblocking agents, fillers (e.g., inorganic fillers), etc. may also be incorporated. These compounds can be used individually or in combination of two or more.

[0050] (Method for producing this composition) This composition can be produced, for example, by mixing the EVOH resin, a compound having a conjugated polyene structure, and a titanium compound by known methods such as dry blending, melt mixing, solution mixing, or impregnation. Among these methods, it is preferable to produce the composition by including a step of melt mixing the composition raw materials containing the EVOH resin and the titanium compound. Furthermore, these production methods can be combined in any way.

[0051] Examples of the dry blending method include (i) a method of dry blending pelletized EVOH resin with a compound having a conjugated polyene structure and a titanium compound using a tumbler or the like.

[0052] Examples of the melt mixing method include (ii) a method of melting and kneading a dry blend obtained by dry blending pelletized EVOH resin, a compound having a conjugated polyene structure, and a titanium compound, and (iii) a method of melting and kneading by adding a compound having a conjugated polyene structure and a titanium compound to molten EVOH resin.

[0053] Examples of the solution mixing method include (iv) preparing a solution using a commercially available EVOH resin, blending a compound having a conjugated polyene structure and a titanium compound therein, solidifying and molding, and then separating the solid and liquid by known means and drying, and (v) during the EVOH resin manufacturing process, adding a compound having a conjugated polyene structure and a titanium compound to an ethylene-vinyl ester copolymer solution before saponification or a homogeneous solution of EVOH resin (water / alcohol solution, etc.), solidifying and molding, and then separating the solid and liquid by known means and drying.

[0054] Examples of the impregnation method include (vi) contacting pelletized EVOH resin with an aqueous solution containing a compound having a conjugated polyene structure and a titanium compound, thereby incorporating the compound having a conjugated polyene structure and the titanium compound into the EVOH resin, and then drying it. As the aqueous solution containing the titanium compound, an aqueous solution of a compound having a conjugated polyene structure and a titanium compound, or a solution obtained by immersing a compound having a conjugated polyene structure and a titanium compound in water containing various chemicals to elute titanium ions can be used.

[0055] In the aforementioned impregnation method, the content (in terms of metal) of compounds having a conjugated polyene structure and titanium compounds can be controlled by the concentration of titanium compounds in the aqueous solution into which the EVOH resin is immersed, as well as the immersion temperature and immersion time. The immersion temperature and immersion time are typically 0.5 to 48 hours, preferably 1 to 36 hours, and the immersion temperature is typically 10 to 40°C, preferably 20 to 35°C.

[0056] Various drying methods can be used in each of the above manufacturing methods, including static drying and fluidized bed drying. These methods can also be combined.

[0057] As described above, in this embodiment, it is possible to combine the different methods described above. Among them, the melt mixing method is preferred in that it yields a composition with greater productivity and more pronounced effects of the present invention, and method (ii) is particularly preferred. Furthermore, when using the other thermoplastic resins and other compounding agents, they may be compounded by conventional methods according to the above manufacturing method.

[0058] The shape of the composition obtained by each of the above manufacturing methods is arbitrary, but it is preferably in the form of pellets. The aforementioned pellets can be spherical, oval, cylindrical, cubic, or rectangular, but are usually oval or cylindrical. From the viewpoint of convenience when used later as a molding material, the size of the oval pellets is usually 1 to 10 mm in length, preferably 2 to 6 mm, and more preferably 2.5 to 5.5 mm in length, and the length is usually 1.5 to 30 mm, preferably 3 to 20 mm, and more preferably 3.5 to 10 mm. In the case of cylindrical pellets, the diameter of the base is usually 1 to 6 mm, preferably 2 to 5 mm, and the length is usually 1 to 6 mm, preferably 2 to 5 mm. Furthermore, it is preferable that the shape and size of the pelletized EVOH resin used in each of the above manufacturing methods are also the same.

[0059] The water content of this composition before melt molding is typically 0.01 to 0.5% by mass, preferably 0.05 to 0.35% by mass, and particularly preferably 0.1 to 0.3% by mass. Here, "melt molding" before melt molding refers to the process of melting a material to create a certain shape. Examples include melting a composition to form pellets or melting a composition to form a film.

[0060] The water content of this composition is measured and calculated by the following method. The mass of the composition before drying (W1) is weighed using an electronic balance, dried in a hot air dryer at 150°C for 5 hours, and then weighed after cooling in a desiccator for 30 minutes (W2). The result is then calculated using the following formula. Moisture content (mass%)=[(W1-W2) / W1]×100

[0061] Furthermore, if the composition is in the form of pellets, it is also preferable to attach a known lubricant to the surface of the pellets in order to stabilize the feedability during melt molding. Examples of lubricants include higher fatty acids with 12 or more carbon atoms (e.g., lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, etc.), higher fatty acid esters (methyl esters, isopropyl esters, butyl esters, octyl esters, etc. of higher fatty acids), higher fatty acid amides (e.g., saturated higher fatty acid amides such as lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, behenic acid amide; unsaturated higher fatty acid amides such as oleic acid amide, erucic acid amide; bis-higher fatty acid amides such as ethylenebis-stearic acid amide, ethylene-bis-oleic acid amide, ethylene-bis-erucic acid amide, ethylene-bis-lauric acid amide, etc.), low molecular weight polyolefins (e.g., low molecular weight polyethylene or low molecular weight polypropylene with a molecular weight of about 500 to 10000, or acid-modified products thereof), higher alcohols with 6 or more carbon atoms, ester oligomers, fluoroethylene resins, etc. These compounds can be used individually or in combination of two or more. The content of such lubricants is usually 5% by mass or less, preferably 1% by mass or less, of the composition. The lower limit is usually 0% by mass.

[0062] The composition thus obtained can be prepared in various forms, such as pellets, powder, or liquid, and provided as a molding material for various molded products. In particular, in this embodiment, it is preferable that the effects of the present invention be obtained more efficiently when the composition is provided as a material for melt molding. Furthermore, this composition also includes compositions obtained by mixing resins other than the EVOH resin used in this composition.

[0063] The base film may be, for example, a single-layer film (EVOH layer) molded from this composition, or a multi-layer film having at least one EVOH layer.

[0064] [Layer containing thermoplastic resin] The base film preferably has a layer containing a thermoplastic resin (hereinafter sometimes referred to as the "thermoplastic resin layer"). Having a thermoplastic resin layer in the base film tends to further enhance the mechanical strength and water vapor barrier properties of the vapor-deposited film. Furthermore, properties such as heat sealability and mechanical strength can be imparted depending on the type of thermoplastic resin constituting the thermoplastic resin layer.

[0065] The thermoplastic resins mentioned above are, excluding the EVOH resin, and include, for example, polyethylene such as linear low-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, medium-density polyethylene, and high-density polyethylene; ethylene-vinyl acetate copolymers, ionomers, ethylene-propylene (block or random) copolymers, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, polypropylene, propylene-α-olefin copolymers, polybutene, polypentene, and other olefins, either alone or in copolymer form, or those graft-modified with unsaturated carboxylic acids or their esters; polyolefins; polyesters; polyamides (including copolymerized polyamides); polyvinyl chloride; polyvinylidene chloride; acrylic resins; polystyrene; polyvinyl esters; polyester elastomers; polyurethane elastomers; chlorinated polystyrene; chlorinated polypropylene; aromatic polyketones or aliphatic polyketones, and polyalcohols obtained by reducing these; polyacetals; and polycarbonates. Among these, polyolefins are preferred from the viewpoint of excellent heat sealability and mechanical properties, polypropylene and polyethylene are more preferred, and polyethylene is particularly preferred. These can be used individually or in combination of two or more types. Linear low-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, medium-density polyethylene, and high-density polyethylene are all commonly used terms to describe different types of polyethylene.

[0066] When polyethylene is used as the thermoplastic resin, the melt flow rate (MFR) of the polyethylene, measured according to JIS K 7210:2014 (190°C, load 2.16 kg), is preferably 0.10 to 7.5 g / 10 min, more preferably 0.15 to 5.0 g / 10 min, and particularly preferably 0.2 to 2.5 g / 10 min. When the MFR of polyethylene is within the above range, the molding stability tends to be better.

[0067] The content of thermoplastic resin in the thermoplastic resin layer is not particularly limited, but it is preferable that the thermoplastic resin is the main component (i.e., the thermoplastic resin content in the thermoplastic resin layer is 50% by mass or more). A thermoplastic resin content of 60% by mass or more is more preferable, 70% by mass or more is even more preferable, and 80% by mass or more, 90% by mass or more, 95% by mass or more, and 100% by mass are particularly preferable.

[0068] The thermoplastic resin layer may contain components other than thermoplastic resins, such as blocking inhibitors, processing aids, resins other than thermoplastic resins, carboxylic acid compounds, phosphoric acid compounds, boron compounds, metal salts, stabilizers, antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, surfactants, desiccants, crosslinking agents, and reinforcing agents for various fibers, in a range that does not impair the effects of the present invention, generally in a range of 20% by mass or less. These may be used individually or in combination of two or more.

[0069] [Layer containing adhesive resin] The base film may have a layer containing an adhesive resin (hereinafter sometimes referred to as the "adhesive resin layer"). The presence of an adhesive resin layer in the base film tends to result in better appearance characteristics (film surface) of the vapor-deposited film.

[0070] The adhesive resin is not particularly limited, but it is preferable to use a polyolefin having a carboxyl group, a carboxylic acid anhydride group, or an epoxy group, and more preferably a polyolefin having a carboxylic acid anhydride group. Such adhesive resins tend to have excellent adhesion to the EVOH layer and / or thermoplastic resin layer.

[0071] Examples of polyolefins containing carboxyl groups include polyolefins copolymerized with acrylic acid or methacrylic acid. In this case, all or part of the carboxyl groups contained in the polyolefin may exist in the form of metal salts, as is the case with ionomers. Examples of polyolefins having carboxylic acid anhydride groups include polyolefins graft-modified with maleic anhydride or itaconic acid. Examples of polyolefins having epoxy groups include polyolefins copolymerized with glycidyl methacrylate. Among these, polyolefins having carboxylic acid anhydride groups such as maleic anhydride are preferred, and polyethylene having carboxylic acid anhydride groups is particularly preferred. These can be used individually or in combination of two or more.

[0072] The melt flow rate (MFR) of the adhesive resin, measured according to JIS K 7210:2014 (190°C, load 2.16 kg), is not particularly limited, but is preferably 0.1 to 20.0 g / 10 min, and more preferably 1.0 to 10.0 g / 10 min. When the MFR of the adhesive resin is within this range, the molding stability tends to be better.

[0073] The content of adhesive resin in the adhesive resin layer is not particularly limited, but it is preferable that the adhesive resin is the main component (i.e., the content of adhesive resin in the adhesive resin layer is 50% by mass or more). In particular, an adhesive resin content of 60% by mass or more is more preferable, 70% by mass or more is even more preferable, and 80% by mass or more, 90% by mass or more, 95% by mass or more, and 100% by mass are particularly preferable.

[0074] The adhesive resin layer may contain components other than the adhesive resin, such as blocking inhibitors, processing aids, resins other than the adhesive resin, in a range that does not impair the effects of the present invention, generally in a range of 20% by mass or less. These components may include, for example, antiblocking agents, processing aids, resins other than the adhesive resin, carboxylic acid compounds, phosphoric acid compounds, boron compounds, metal salts, stabilizers, antioxidants, ultraviolet absorbers, plasticizers, antistatic agents, lubricants, colorants, fillers, surfactants, desiccants, crosslinking agents, and reinforcing agents for various fibers. These may be used individually or in combination of two or more.

[0075] [Method for manufacturing base film] The base film can typically be manufactured by extruding the composition from a die, forming it into a film, and stretching it as needed. Furthermore, if the base film has a thermoplastic resin layer or an adhesive resin layer, it can be manufactured by conventional co-extrusion, in which each raw material composition forming the EVOH layer, thermoplastic resin layer, and adhesive resin layer is extruded and laminated from separate dies or a common die, and then stretched as needed. For example, an annular die or a T-die can be used as the die. Furthermore, examples of the molding methods include methods that involve melting and molding, such as extrusion molding, blow molding, injection molding, thermoforming, and inflation molding, as well as methods that involve molding in a solution, such as casting.

[0076] The base film only needs to have an EVOH layer, and the other layer configurations are not particularly limited, but it is preferable that the EVOH layer is at least one of the surface layers. Since the base film has an EVOH layer, a vapor-deposited film with excellent transparency can be obtained. The base film is preferably multilayered, and when the EVOH layer is referred to as "(A) layer", the thermoplastic resin layer as "(B) layer", and the adhesive resin layer as "(C) layer", examples of the layer configuration include (B) layer / (A) layer, (B) layer / (A) layer / (B) layer, (B) layer / (C) layer / (A) layer / (B) layer, (B) layer / (C) layer / (A) layer / (C) layer / (B) layer, (B) layer / (A) layer / (B) layer / (A) layer / (B) layer, (B) layer / (B) layer / (C) layer / (A) layer / (C) layer / (B) layer / (B) layer, (A) layer / (C) layer / (B) layer / (B) layer, (A) layer / (C) layer / (B) layer / (B) layer, and so on.

[0077] In the above examples, layers (B) and (C) are given as examples of layers other than layer (A), but layers other than layer (A) are not limited to these. Furthermore, it is preferable that the base film does not contain a layer formed from a composition mainly containing a polyamide resin (i.e., a composition containing 50% by mass or more of polyamide resin). Furthermore, the " / " shown in the above example means that the layers on both sides are directly stacked.

[0078] The base film obtained in this manner may be stretched as needed, and if stretched, uniaxial stretching is preferred. The stretching ratio in the aforementioned uniaxially oriented film is preferably 3 times or more, more preferably 4 times or more, and particularly preferably 5 times or more. If the stretching ratio is less than 3 times, there is a tendency for thickness unevenness due to stretching to occur and the gas barrier properties to decrease. Furthermore, the upper limit of the stretching ratio is preferably 12 times or less, more preferably 10 times or less, and particularly preferably 8 times or less. If the stretching ratio exceeds 12 times, the film surface after stretching tends to deteriorate. Uniaxially oriented films have advantages from an economic standpoint, such as being easy to tear (making it easier to open packaging materials when used as such), and having improved gas barrier properties.

[0079] The stretching direction of the uniaxially oriented film is not particularly limited and may be in the longitudinal direction (MD direction) or the width direction (TD direction), but uniaxial stretching in the longitudinal direction (MD direction) is preferred, and it is especially preferred that it is not substantially stretched in a direction other than the stretching direction. The stretched state of the base film (unstretched, uniaxially stretched, or biaxially stretched, etc.) can be confirmed by using general methods for analyzing the orientation of the resin (e.g., wide-angle X-ray scattering (WAXS)).

[0080] The stretching method for the uniaxially oriented film is not particularly limited, but examples include tenter stretching, tubular stretching, and roll stretching. Among these, uniaxial stretching by roll stretching is preferred from the viewpoint of manufacturing cost. Furthermore, if the base film is obtained by inflation molding, roll stretching is preferred.

[0081] The stretching temperature during uniaxial stretching is not particularly limited, but is generally between 50 and 130°C.

[0082] The overall thickness of the base film is not particularly limited and can be set appropriately depending on the application. The thickness of the base film is preferably 10 μm or more, and more preferably 15 μm or more. A base film thickness of 10 μm or more tends to improve industrial productivity and mechanical properties. Furthermore, the thickness of the base film is preferably 100 μm or less, and more preferably 50 μm or less. A base film thickness of 100 μm or less tends to improve industrial productivity and economic efficiency. Note that the thickness of the base film, which is a uniaxially oriented film, refers to the thickness after stretching.

[0083] Furthermore, when the base film is a multilayer film, the thickness of the EVOH layer is preferably 0.5 μm or more, more preferably 0.8 μm or more, and particularly preferably 1 μm or more. A thickness of 0.5 μm or more in the EVOH layer tends to improve gas barrier properties. On the other hand, the thickness of the EVOH layer is preferably 20 μm or less, more preferably 10 μm or less, and particularly preferably 5 μm or less. A thickness of 20 μm or less for the EVOH layer tends to result in good appearance characteristics (film surface). Note that the thickness of a uniaxially oriented multilayer film refers to the thickness after stretching. Furthermore, if the EVOH layer is provided in multiple layers on the base film, it is preferable that the sum of all EVOH layers is within the above range.

[0084] When the base film is a multilayer film, the ratio of the thickness of the EVOH layer to the total thickness of all layers is preferably 30% or less, more preferably 20% or less, and may also be 10% or less, or 5% or less, from the viewpoint of industrial productivity and mechanical properties.

[0085] If the base film has a thermoplastic resin layer, its thickness is preferably 7 to 100 μm, and more preferably 10 to 50 μm, from the viewpoint of industrial productivity and mechanical properties. In the case of a uniaxially oriented base film, the thickness of the thermoplastic resin layer refers to the thickness after stretching. Furthermore, if the thermoplastic resin layer is provided in multiple layers on the base film, it is preferable that the sum of all thermoplastic resin layers is within the above range.

[0086] If the base film has an adhesive resin layer, its thickness is preferably 0.5 to 20 μm, and more preferably 1 to 10 μm, from the viewpoint of industrial productivity and quality stability. In the case of a uniaxially oriented base film, the thickness of the adhesive resin layer refers to the thickness after stretching. Furthermore, if the adhesive resin layer is provided in multiple layers on the base film, it is preferable that the sum of all adhesive resin layers is within the above range.

[0087] The internal haze value of the base film is preferably less than 0.4%, more preferably 0.3% or less, even more preferably 0.2% or less, and particularly preferably 0%. Such measurement can be performed using a base film with a thickness of 33 μm and a haze meter in accordance with ASTM D1003.

[0088] <Metal deposition layer> The metal vapor-deposited layer laminated on the base film is obtained by vapor-depositing a single metal or two or more alloys. Furthermore, from the viewpoint of gas barrier properties, it is preferable that the metal vapor-deposited layer is laminated on the EVOH layer of the base film.

[0089] Examples of metals used in the aforementioned metal deposition layer include those classified as aluminum group elements (aluminum, gallium, indium, etc.), tin group elements (titanium, zirconium, tin, hafnium, etc.), precious metals (copper, silver, gold, etc.), chromium group elements (chromium, molybdenum, tungsten, etc.), iron group elements (iron, cobalt, nickel, etc.), and alloys thereof. Among these, at least one selected from the group consisting of aluminum, gold, silver, copper, titanium, nickel, chromium, tin, and indium is preferred due to its general availability and ease of handling, with aluminum being particularly preferred.

[0090] Furthermore, the metal used in the metal vapor deposition layer preferably contains metal compounds such as metal oxides, metal carbides, and metal nitrides, with metal oxides being preferred among these metal compounds. The content of such metal compounds is preferably 50% by mass or more of the metal used in the metal vapor deposition layer, more preferably 80% by mass or more, even more preferably 90% by mass or more, and may be 100% by mass.

[0091] Furthermore, the metal vapor deposition layer can be identified by analyzing the cross-section of the laminate using energy-dispersive spectroscopy (EDS).

[0092] <Method for manufacturing this vapor-deposited film> This vapor-deposited film can be manufactured by laminating the metal vapor-deposited layer onto the base film.

[0093] There are no particular restrictions on the method for laminating the metal vapor deposition layer onto the substrate film. For example, any known vapor deposition method such as vacuum deposition, sputtering, ion plating (PVD method), or chemical vapor deposition (CVD method) may be used as appropriate.

[0094] The thickness of the metal deposition layer is typically 1 to 100 nm, preferably 3 to 50 nm, and more preferably 5 to 20 nm. If the thickness of the metal deposition layer is less than 1 nm, the gas barrier properties tend to be insufficient. On the other hand, if the thickness exceeds 100 nm, no improvement in gas barrier properties is obtained, and flexibility and manufacturing costs tend to increase.

[0095] The vapor-deposited film obtained in this manner exhibits excellent surface smoothness of the vapor-deposited surface. The root mean square height (Sq) of the vapor-deposited surface of the vapor-deposited film is preferably 0.10 μm or less, more preferably 0.09 μm or less, and even more preferably 0.08 μm or less. A smaller root mean square height (Sq) indicates a smoother surface and is therefore preferable. The method for measuring the root mean square height (Sq) can be the method specified in ISO 25178, and specifically, it can be measured by the method described in the examples below.

[0096] This vapor-deposited film can be suitably used as a molded body or packaging material for packaging general foods, as well as condiments such as mayonnaise and dressings, fermented foods such as miso, oily foods such as salad oil, snack foods, beverages, cosmetics, pharmaceuticals, etc., or as part of a multilayer structure for forming these.

[0097] <<Multilayer structure>> The aforementioned multilayer structure is formed by laminating another layer onto the vapor-deposited film. The other layer laminated onto the vapor-deposited film is not particularly limited and may be a layer formed from a composition containing the thermoplastic resin exemplified above or the adhesive resin exemplified above.

[0098] Various known manufacturing methods can be used to produce multilayer structures, such as dry lamination, sand lamination, extrusion lamination, co-extrusion lamination, and solution coating.

[0099] <<Molded body>> Using this vapor-deposited film or the multilayer structure, it is possible to obtain cup- or tray-shaped molded articles. In such cases, a deep drawing method is usually employed, specifically including vacuum forming, pressure forming, vacuum pressure forming, and plug-assisted vacuum pressure forming. Furthermore, using the aforementioned multilayer structure, it is possible to obtain molded products such as tubes, bottles, multilayer containers (laminated structures), and food containers from multilayer parisons (hollow tubular premolded products before blowing). In such cases, blow molding is usually employed, and examples include extrusion blow molding (double-head type, mold movement type, parison shift type, rotary type, accumulator type, horizontal parison type, etc.), cold parison blow molding, injection blow molding, and biaxial stretch blow molding (extrusion cold parison biaxial stretch blow molding, injection cold parison biaxial stretch blow molding, injection molding in-line biaxial stretch blow molding, etc.). The resulting laminate can be subjected to heat treatment, cooling treatment, rolling treatment, printing treatment, dry lamination treatment, solution or molten coating treatment, bag making, deep drawing, box making, tube making, splitting, etc., as needed. [Examples]

[0100] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. In the examples, "parts" and "%" refer to mass.

[0101] <Example 1> [Preparation of composition pellets] As the EVOH resin, pellets of EVOH resin with an ethylene structural unit content of 29 mol% and a degree of saponification of 99.6 mol% were used. Furthermore, sorbic acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used as a compound having a conjugated polyene structure, and titanium dioxide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used as a titanium compound. The EVOH resin pellets were dry-blended with sorbic acid at a concentration of 200 ppm relative to the mass of the composition, and titanium dioxide at a concentration of 0.1 ppm relative to the mass of the composition (on a metal basis) to obtain a mixture. The mixture was supplied to a twin-screw extruder (20 mmΦ) equipped with a two-hole die, and the extruded strands were air-cooled and solidified on a belt conveyor under the following extrusion conditions. Next, pellets of the composition were obtained by cutting the solidified strands. (Extrusion conditions) Extruder setting temperature (℃): C1 / C2 / C3 / C4 / C5 / C6 =150 / 200 / 210 / 210 / 210 / 210

[0102] [Preparation of single-layer film] A melt-extruded single-layer film was obtained by extruding the resulting composition pellets under the following conditions. (Film production conditions) • Extruder: Brabender Plastograph EC-plus • Screw: Single shaft, 20mm diameter, full flight • Cylinder section temperature setting: 190~210℃ • Cooling roll setting temperature: 80℃ Film thickness: 30μm

[0103] [Formation of metal vapor deposition layer] Using a batch-type deposition equipment manufactured by Showa Vacuum Co., Ltd., the above single-layer film was used as a base film, and an aluminum metal deposition layer was laminated while the surface temperature of the base film was 40°C or lower to obtain the deposition film of Example 1.

[0104] <Example 2> In Example 1, the metallic content of titanium dioxide was changed to 1 ppm relative to the mass of the composition, and a vapor-deposited film was obtained in the same manner as in Example 1.

[0105] <Example 3> In Example 1, the sorbic acid content was changed to 1500 ppm relative to the mass of the composition, and a vapor-deposited film was obtained in the same manner as in Example 1.

[0106] <Comparative Example 1> In Example 1, a vapor-deposited film was obtained in the same manner as in Example 1, without using titanium dioxide.

[0107] <Comparative Example 2> In Example 1, the metallic content of titanium dioxide was changed to 10 ppm relative to the mass of the composition, and a vapor-deposited film was obtained in the same manner as in Example 1.

[0108] <Comparative Example 3> In Example 1, a vapor-deposited film was obtained in the same manner as in Example 1, but without using sorbic acid.

[0109] The surface smoothness of the vapor-deposited films obtained in Examples 1-3 and Comparative Examples 1-3 was measured as follows. The measurement results are shown in Table 1 below.

[0110] [Surface smoothness] The metal vapor deposition layer side surface (vapor deposition surface) of the vapor-deposited film was observed using a laser microscope (Olympus LEXTOLS5000) under the following conditions. • Light source: 405nm wavelength light source • Objective lens: 100x magnification • Optical zoom: 1.0x Image area: 129 μm × 129 μm • Resolution: 1024 x 1024 pixels The root mean square height (Sq) of the vapor-deposited surface was measured from an arbitrary point on the surface using the ISO 25178 method. A smaller root mean square height (Sq) indicates a smoother surface.

[0111] [Table 1]

[0112] From the results shown in Table 1 above, it can be seen that the vapor-deposited films of Examples 1 to 3, which contain a compound having a conjugated polyene structure and a specific trace amount of titanium compound, have a small root mean square height (Sq) and a smooth vapor-deposited surface. On the other hand, the vapor-deposited films of Comparative Example 1, which does not contain a titanium compound, Comparative Example 2, which contains a titanium compound beyond a specific range, and Comparative Example 3, which does not contain a compound having a conjugated polyene structure, all have a large root mean square height (Sq) and their vapor-deposited surfaces are not smooth.

[0113] Furthermore, even when the base film constituting the vapor-deposited films of Examples 1 to 3 is a multilayer film obtained by co-extruding the composition with a thermoplastic resin (such as polyethylene resin) instead of the single-layer film, the effect of excellent surface smoothness of the vapor-deposited surface can be obtained. Moreover, the effect of excellent surface smoothness of the vapor-deposited surface can also be obtained in multilayer structures, molded articles, and food containers formed using the vapor-deposited films of Examples 1 to 3. [Industrial applicability]

[0114] This vapor-deposited film can be suitably used as a molded body or packaging material for packaging general foods, as well as condiments such as mayonnaise and dressings, fermented foods such as miso, oily foods such as salad oil, snack foods, beverages, cosmetics, pharmaceuticals, etc., or as part of a multilayer structure for forming these.

Claims

1. A vapor-deposited film comprising a base film having a layer containing a composition comprising an ethylene-vinyl alcohol copolymer, a compound having a conjugated polyene structure, and a titanium compound, and a metal vapor-deposited layer laminated on the base film, wherein the metal equivalent content of the titanium compound is 0.001 ppm or more and less than 3 ppm relative to the mass of the composition.

2. The vapor-deposited film according to claim 1, wherein the content of the compound having the conjugated polyene structure is 1 to 3000 ppm relative to the mass of the composition.

3. The vapor-deposited film according to claim 1 or 2, wherein the mass ratio of the content of the compound having the conjugated polyene structure to the metal equivalent content of the titanium compound is 0.3 to 1,000,000.

4. The vapor-deposited film according to claim 1 or 2, wherein the base film is a multilayer film further having a layer containing a thermoplastic resin.

5. The vapor-deposited film according to claim 1 or 2, wherein the metal of the metal vapor-deposited layer is at least one selected from the group consisting of aluminum, gold, silver, copper, titanium, nickel, chromium, tin, and indium.

6. A multilayer structure comprising the vapor-deposited film according to claim 1 or 2.

7. A molded article comprising the vapor-deposited film according to claim 1 or 2.

8. A food container comprising the multilayer structure described in claim 6.

9. A method for manufacturing a vapor-deposited film according to claim 1 or 2, comprising the step of laminating a metal vapor-deposited layer onto the base film.

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