JP4808752B2 - Gas barrier film and laminate thereof - Google Patents

Description

  The present invention relates to a method for producing a gas barrier film suitable for a packaging material having transparency and excellent gas barrier properties such as oxygen and water vapor, particularly gas barrier properties under high humidity.

In recent years, as a barrier material against oxygen or water vapor, inorganic oxides such as silicon oxide and aluminum oxide have been formed on film substrates by vacuum deposition, sputtering, ion plating, chemical vapor deposition, etc. A transparent gas barrier film is attracting attention. Such a transparent gas barrier film is a film obtained by depositing an inorganic oxide on a base material surface made of a biaxially stretched polyester film that is generally excellent in transparency and rigidity. When used as a packaging film, the inorganic oxide may be cracked by rubbing or stretching during post-processing printing or laminating or filling the contents, and the gas barrier property may be lowered.
On the other hand, a method of laminating a polyvinyl alcohol having a gas barrier property and an ethylene / vinyl alcohol copolymer on a biaxially stretched film substrate (for example, Patent Document 1), or a composition of polyvinyl alcohol and poly (meth) acrylic acid A method of coating a biaxially stretched film substrate (for example, Patent Document 2) has been proposed. However, the gas barrier film formed by laminating polyvinyl alcohol has a reduced oxygen barrier property under high humidity, and the composition of polyvinyl alcohol and poly (meth) acrylic acid has sufficiently advanced esterification, In order to improve the gas barrier property of the film, heating at a high temperature for a long time is required, which causes a problem in productivity, and the gas barrier property under high humidity is insufficient. Further, since the film is colored by reacting at high temperature for a long time and the appearance is impaired, improvement for food packaging is necessary.
On the other hand, since a composition of polyvinyl alcohol and poly (meth) acrylic acid requires a long reaction at a high temperature for esterification, a method of adding a crosslinking agent component such as an isocyanate compound to polyacrylic acid (for example, a patent) Document 3) and a method of reacting with a metal ion (for example, Patent Document 4) have been proposed. In this method, polyacrylic acid is crosslinked with a crosslinking agent component as described in Examples. As shown, it requires treatment at 180 to 200 ° C. for 5 minutes and at a high temperature.

JP-A-60-157830 (Claims) Japanese Patent No. 3203287 (Claim 1) JP 2001-310425 A (Claim 1, Example 1) JP 2003-171419 A (Claim 1, Table 1)

  Therefore, the present invention provides an excellent transparency and gas barrier property under high humidity without crosslinking the unsaturated carboxylic acid compound by heat treatment at a high temperature of 180 to 200 ° C., and a gas barrier under low humidity. The purpose was to develop a method for stably obtaining a gas barrier film having good properties.

  In the present invention, after applying a polyvalent metal salt solution of an unsaturated carboxylic acid compound having a polymerization degree of less than 20 to the base material layer, an electron beam is applied to the polyvalent metal salt of the unsaturated carboxylic acid compound in the presence of a solvent. A method for producing a gas barrier film characterized by irradiation is provided.

  In the present invention, the base layer is coated with a solution containing an unsaturated carboxylic acid compound having a polymerization degree of less than 20 and a polyvalent metal compound to form a polyvalent metal salt of the unsaturated carboxylic acid compound. The present invention also provides a method for producing a gas barrier film characterized by irradiating an electron beam in the presence of a solvent.

  When polymerizing an unsaturated carboxylic acid compound polyvalent metal salt having a degree of polymerization of less than 20, the solution of the unsaturated carboxylic acid compound polyvalent metal salt is irradiated with an electron beam to produce an unsaturated carboxylic acid compound polyvalent metal salt. By polymerizing, a gas barrier film having excellent transparency and gas barrier properties can be produced.

Unsaturated carboxylic acid compound The unsaturated carboxylic acid compound according to the present invention is a carboxylic acid compound having an α, β-ethylenically unsaturated group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, and the like. Less than, preferably a monomer or 10 or less polymer. A polymer obtained by polymerizing a polymer (polymer compound) having a degree of polymerization exceeding 20 with a polyvalent metal compound described later may not have improved gas barrier properties under high humidity.
Among these unsaturated carboxylic acid compounds, a salt in which a monomer is completely neutralized with a polyvalent metal compound is easy to form, and a film obtained by polymerizing the salt is excellent in gas barrier properties, which is preferable.

Polyvalent metal compound The polyvalent metal compound according to the present invention specifically includes magnesium (Mg), calcium (Ca), barium (Ba), zinc (Zn), copper (Cu), cobalt (Co), nickel (Ni), aluminum (Al), iron (Fe) and other divalent or higher metals, oxides, hydroxides, halides, carbonates, phosphates, phosphites, hypophosphorous acid of these metals Salt, sulfate or sulfite. Among these metal compounds, divalent metal compounds are preferable, and magnesium oxide, calcium oxide, barium oxide, zinc oxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, zinc hydroxide, and the like are particularly preferable. When these divalent metal compounds are used, the gas barrier property under high humidity of the film obtained by polymerizing the salt with the unsaturated carboxylic acid is particularly excellent. At least 1 type is used for these, and even 1 type may be used or 2 or more types may be used together.

Polyvalent metal salt of unsaturated carboxylic acid compound The polyvalent metal salt of the unsaturated carboxylic acid compound according to the present invention is a salt of an unsaturated carboxylic acid compound having a polymerization degree of less than 20 and the polyvalent metal compound. These unsaturated carboxylic acid compound polyvalent metal salts may be one kind or a mixture of two or more kinds. Among these unsaturated carboxylic acid compound polyvalent metal salts, the gas barrier film from which zinc (meth) acrylate is obtained is particularly excellent in hot water resistance, which is preferable.

Base Material Layer The base material layer according to the present invention is not particularly limited as long as it can be applied with a solution of the polyvalent metal salt of the unsaturated carboxylic acid compound, and is not limited to thermosetting resin, thermoplastic resin or paper. Examples of organic materials such as glass, porcelain, ceramics, cement or inorganic materials such as metals such as aluminum, iron, copper, and stainless steel, and base materials with a multilayer structure composed of organic materials or combinations of organic materials and inorganic materials can do.
Further, the shape of the base material layer is not particularly limited, and examples thereof include a sheet or film-like material, a tray, a cup, and a hollow body.
When an organic material such as a thermosetting resin, a thermoplastic resin, or paper is used as a material for these base material layers, a laminate having a gas barrier film made of a polyvalent metal salt polymer of an unsaturated carboxylic acid compound Can be used as
Examples of the thermosetting resin include various known thermosetting resins such as epoxy resins, unsaturated polyester resins, phenol resins, urea / melamine resins, polyurethane resins, silicone resins, and polyimides.
As the thermoplastic resin, various known thermoplastic resins such as polyolefin (polyethylene, polypropylene, poly-4-methyl / 1-pentene, polybutene, etc.), polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamide (Nylon-6, nylon-66, polymetaxylene adipamide, etc.), polyvinyl chloride, polyimide, ethylene / vinyl acetate copolymer or saponified product thereof, polyvinyl alcohol, polyacrylonitrile, polycarbonate, polystyrene, ionomer, fluororesin Or the mixture etc. can be illustrated. Of these, thermoplastic resins having good stretchability and transparency, such as polypropylene, polyethylene terephthalate, and polyamide, are preferable. The base material layer made of these thermoplastic resins may be a single layer or a laminate made of two or more kinds of thermoplastic resins depending on the use of the gas barrier film. In addition, an inorganic compound such as aluminum, zinc or silica or an oxide thereof may be deposited on the surface of the base material layer, polyvinylidene chloride, polyvinyl alcohol, ethylene / vinyl alcohol copolymer, acrylic resin, A urethane-based resin or the like may be coated.
In addition, in order to improve the adhesion with the gas barrier film, these base material layers have surface activity such as corona treatment, flame treatment, plasma treatment, undercoat treatment, primer coat treatment, flame treatment, etc. It is also possible to carry out the conversion process.

Method for Producing Gas Barrier Film In the method for producing a gas barrier film of the present invention, after applying a polyvalent metal salt solution of an unsaturated carboxylic acid compound having a degree of polymerization of less than 20 to a base material layer, A method for producing a gas barrier film, comprising irradiating a polyvalent metal salt with an electron beam in the presence of a solvent.
As a method for preparing a solution of an unsaturated carboxylic acid compound polyvalent metal salt, after previously reacting the unsaturated carboxylic acid and the polyvalent metal compound to obtain a polyvalent metal salt of an unsaturated carboxylic acid compound, The unsaturated carboxylic acid compound polyvalent metal salt may be dissolved in a solvent such as water to form a solution, or the unsaturated carboxylic acid compound and the polyvalent metal compound may be directly dissolved in a solvent to form a polyvalent metal salt solution. Good.
As a method for producing a gas barrier film of the present invention, when the unsaturated carboxylic acid compound and the polyvalent metal compound are directly dissolved in a solvent, that is, a solution containing the unsaturated carboxylic acid compound and the polyvalent metal compound is used. In this case, it is preferable to add the polyvalent metal compound in an amount exceeding 0.3 chemical equivalents relative to the unsaturated carboxylic acid compound. When a mixed solution having a polyvalent metal compound addition amount of 0.3 chemical equivalent or less is used, a gas barrier film having a large content of free carboxylic acid groups may be formed, resulting in a film having a low gas barrier property. is there. The upper limit of the amount of polyvalent metal compound is not particularly limited, but when the amount of polyvalent metal compound exceeds 1 chemical equivalent, the amount of unreacted polyvalent metal compound increases. Preferably, 2 chemical equivalents or less are sufficient.
In addition, when a mixed solution of an unsaturated carboxylic acid compound and a polyvalent metal compound is used, the unsaturated carboxylic acid compound is usually added while the unsaturated carboxylic acid compound and the polyvalent metal compound are dissolved in a solvent. Although a valent metal salt is formed, it is preferable to mix for 1 minute or more in order to ensure the formation of the polyvalent metal salt.
Examples of the solvent used for preparing the solution of the polyvalent metal salt of the unsaturated carboxylic acid compound include water, lower alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, organic solvents such as acetone and methyl ethyl ketone, or a mixed solvent thereof. Water is most preferred.
As a method of applying a solution of an unsaturated carboxylic acid compound polyvalent metal salt to the base material layer, a method of applying the solution to the surface of the base material layer, a method of immersing the base material layer in the solution, Various known coating methods such as a method of spraying on the surface of the base material layer can be adopted.
Examples of a method for applying a polyvalent metal salt solution of an unsaturated carboxylic acid compound to the base material layer include gravure coaters such as an air knife coater, direct gravure coater, gravure offset, arc gravure coater, gravure reverse and jet nozzle method. , Reverse roll coaters such as top feed reverse coater, bottom feed reverse coater and nozzle feed reverse coater, 5-roll coater, lip coater, bar coater, bar reverse coater, die coater, etc. What is necessary is just to apply | coat so that it may become 0.05-10 g / m < ² > in the quantity (solid content) in the solution (solid content) of a saturated carboxylic acid compound polyvalent metal salt, Preferably it is 0.1-5 g / m < ² >.

When dissolving the polyvalent metal salt of the unsaturated carboxylic acid compound or when dissolving the unsaturated carboxylic acid compound and the polyvalent metal compound, methyl (meth) acrylate, as long as the object of the present invention is not impaired, Ethyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, PEG # 200 • di (meth) acrylate, PEG # 400 • di ( Acrylic acid divalent esters of glycols such as (meth) acrylate, PEG # 600 • di (meth) acrylate, neopentyl glycol • di (meth) acrylate, 1,4-butanediol • di (meth) acrylate, and other Vinyl esthetics such as saturated carboxylic acid (di) ester compounds and vinyl acetate Monomers such as compounds or low molecular weight compounds, polyvinyl alcohol, ethylene / vinyl alcohol copolymers, polyvinyl pyrrolidone, polyvinyl ethyl ether, polyacrylamide, polyethyleneimine, starch, gum arabic, methylcellulose and other water-soluble polymers, acrylic High molecular weight compounds such as acid ester polymers, ethylene / acrylic acid copolymers, polyvinyl acetate, ethylene / vinyl acetate copolymers, polyesters and polyurethanes may be added.
Further, when the unsaturated carboxylic acid compound polyvalent metal salt is dissolved, or when the unsaturated carboxylic acid compound and the polyvalent metal compound are dissolved, the lubricant, slip agent, -Various additives such as blocking agents, antistatic agents, antifogging agents, pigments, dyes, inorganic or organic fillers may be added, and in order to improve the wettability with the base material layer, Various surfactants and the like may be added.

When the unsaturated carboxylic acid compound polyvalent metal salt is irradiated with an electron beam to polymerize the unsaturated carboxylic acid compound polyvalent metal salt, it is preferable that the coating liquid is partially dried. In addition, the drying of the coating liquid does not completely remove the solvent, but an appropriate solvent (water if an aqueous solution is used) in the coating liquid, preferably in a state containing the solvent in the range of 20 to 60% by weight. It is preferable to irradiate an electron beam. When the solvent contained in the coating liquid is less than 20% by weight, the oxygen barrier property of the resulting gas barrier film may be lowered, and when the solvent contained in the coating liquid is 60% by weight or more, the obtained gas barrier property. There is a possibility that the oxygen barrier property and appearance of the film, particularly transparency, may be lowered.
Further, the temperature at which the unsaturated carboxylic acid compound polyvalent metal salt is irradiated with an electron beam in the presence of a solvent is not particularly limited as long as the solvent is not at a boiling temperature, but is usually 60 ° C. or less, particularly from room temperature to 50 ° C. It is preferable to carry out in the range of ° C. If the temperature when irradiating the electron beam is too high, the evaporation of the solvent is accelerated and crystals of the unsaturated carboxylic acid compound polyvalent metal salt are likely to precipitate, whereas if the temperature is too low, the unsaturated carboxylic acid is It is necessary to lengthen the time for drying the solvent after polymerizing the acid compound polyvalent metal salt and lengthen the production line of the gas barrier film.

  The electron beam (electron beam; EB) applied to the solution of the unsaturated carboxylic acid compound polyvalent metal salt is not particularly limited as long as the unsaturated carboxylic acid compound polyvalent metal salt is polymerized. It is preferable to use an electron beam having an acceleration voltage of 30 kV to 300 kV and a dose of 10 to 300 kilogray (kGy). If the acceleration voltage is increased too much, the penetration depth of the electron beam becomes deep, and the base material layer may be deteriorated. On the other hand, if the acceleration voltage is reduced too much, the penetration depth of the electron beam becomes shallow, which is not good. The polymerization of the saturated carboxylic acid compound polyvalent metal salt may be insufficient. In addition, if the dose is increased too much, the line speed may be slowed and productivity may be reduced. If the dose is decreased too much, polymerization of the unsaturated carboxylic acid compound polyvalent metal salt may be insufficient. is there.

The polymerization rate of the unsaturated carboxylic acid compound polyvalent metal salt in the present invention was determined by the following measuring method.
Polymerization rate: (B ₁ / B) _{After EB} / (B ₁ / B) _monomer × 100
* _(B 1 / B) _{EB after:} after electron beam irradiation (after polymerization) _(B 1 / B)
* _(B 1 / B) _Monomer: Monomer (before polymerization) of _(B 1 / B)
(B ₁ / B) was defined as described below.
Ratio of absorbance B ₁ based on δC—H of hydrogen bonded to a vinyl group near 830 cm ⁻¹ to absorbance B based on νC═O of carboxylate ions near 1520 cm ⁻¹ in the infrared absorption spectrum (B ₁ / B) Cut out a measurement sample of 1 cm × 3 cm from the (preliminary) polymerized film, and obtained the infrared absorption spectrum of the surface (polymer (A) layer) by infrared total reflection measurement (ATR method). First, absorbance B ₁ and absorbance B are determined.
830 cm ^-1 vicinity absorbance based .delta.C-H of hydrogen binding to vinyl groups _{B 1:} bear and the absorbance of the infrared absorption spectrum of 800 cm ^-1 and 850 cm ^-1 in a straight line (P), between 800～850Cm ^-1 A straight line (Q) is dropped vertically from the maximum absorbance (near 830 cm ⁻¹ ), and the distance (length) of the absorbance between the intersection of the straight line (Q) and the straight line (P) and the maximum absorbance is defined as absorbance B ₁ .
1520 cm ^-1 absorbance based νC = O of carboxylate ions in the vicinity of B: the absorbance of the infrared absorption spectrum of 1480 cm ^-1 and 1630 cm ^-1 connected by a straight line (L), 1480~1630cm maximum absorbance between ^-1 (1520 cm ^The straight line (M) was dropped vertically from the vicinity of ⁻¹ ), and the absorbance distance (length) between the intersection of the straight line (M) and the straight line (L) and the maximum absorbance was defined as absorbance B. The peak position of maximum absorbance (near 1520 cm ⁻¹ ) may vary depending on the metal species of the counter ion. For example, calcium is near 1520 cm ⁻¹ , zinc is near 1520 cm ⁻¹ , and magnesium is near 1540 cm ⁻¹ . is there. Next, the ratio (B ₁ / B) is determined from the absorbance B ₁ and absorbance B determined by the above method. The polymerization rate is determined by measuring the monomer absorbance ratio (B ₁ / B) after the _monomer and electron beam irradiation (after polymerization) (B ₁ / B) _{after EB} .
In addition, the measurement of the infrared spectrum (infrared total reflection measurement: ATR method) in the present invention uses an FT-IR350 apparatus manufactured by JASCO Corporation, and a KRS-5 (Thallium Bromide-Iodide) crystal is attached, and the incident angle is 45. Degree, room temperature, resolution of 4 cm ⁻¹ , and 150 times of integration.

Gas barrier film The gas barrier film obtained by the production method of the present invention usually has an absorbance A ₀ based on νC = O of a carboxylic acid group near 1700 cm ⁻¹ in an infrared absorption spectrum and νC of a carboxylate ion near 1520 cm ^−1. It consists of a polymer of a polyvalent metal salt of an unsaturated carboxylic acid compound in which the ratio (A ₀ / A) to the absorbance A based on ═O is less than 0.25, preferably less than 0.20.
A gas barrier film made of a polymer of a polyvalent metal salt of an unsaturated carboxylic acid compound has a carboxylate ion formed by ionic crosslinking of a carboxylic acid group and a polyvalent metal, and a free carboxylic acid group. Thus, the absorption based on νC═O of the free carboxylic acid group is around 1700 cm ⁻¹ , and the absorption based on νC═O of the carboxylate ion is around 1520 cm ⁻¹ .
Therefore, in the gas barrier film obtained by the production method of the present invention, (A ₀ / A) being less than 0.25 indicates that there are no or few free carboxylic acid groups. A film exceeding .25 has a large content of free carboxylic acid groups, and there is a possibility that the gas barrier resistance is not improved.
Ratio of absorbance A ₀ based on νC═O of a carboxylic acid group near 1700 cm ⁻¹ in the present invention to absorbance A based on νC═O of a carboxylate ion near 1520 cm ⁻¹ in an infrared absorption spectrum (A ₀ / A) Cuts out a measurement sample of 1 cm × 3 cm from a gas barrier film (gas barrier laminate), and measures the infrared absorption spectrum of the surface (unsaturated carboxylic acid compound polyvalent metal salt polymer layer) by infrared total reflection measurement (ATR method). First, the absorbance A ₀ and absorbance A were determined by the following procedure.
1700cm absorbance based νC = O ^-1 vicinity of the carboxylic acid groups _{A 0:} a absorbance of the infrared absorption spectrum of 1660 cm ^-1 and 1760 cm ^-1 connected by a straight line (N), 1660~1760cm maximum absorbance between ^-1 ( The straight line (O) was dropped vertically from around 1700 cm ^−1, and the absorbance distance (length) between the intersection of the straight line (O) and the straight line (N) and the maximum absorbance was defined as absorbance A ₀ .
1520 cm ^-1 vicinity of carboxylate ion of νC = O based upon the absorbance A: connected by a straight line (L) and the absorbance of the infrared absorption spectrum of 1480 cm ^-1 and 1630 cm ^-1, the maximum absorbance between 1480~1630cm ^{-1 (1520cm The} straight line (M) was dropped vertically from the vicinity of ⁻¹ ), and the absorbance distance (length) between the intersection of the straight line (M) and the straight line (L) and the maximum absorbance was defined as absorbance A. The peak position of maximum absorbance (near 1520 cm ⁻¹ ) may vary depending on the metal species of the counter ion. For example, calcium is near 1520 cm ⁻¹ , zinc is near 1520 cm ⁻¹ , magnesium is near 1540 cm ⁻¹ , and In sodium (Na), it is around 1540 cm ⁻¹ .
Next, the ratio (A ₀ / A) was determined from the absorbance A ₀ and the absorbance A determined by the above method.
In addition, the measurement of the infrared spectrum (infrared total reflection measurement: ATR method) in the present invention uses an FT-IR350 apparatus manufactured by JASCO Corporation, and a KRS-5 (Thallium Bromide-Iodide) crystal is attached, and the incident angle is 45. Temperature, room temperature, resolution of 4 cm ⁻¹ , and accumulation of 150 times.

  The gas barrier film obtained by the production method of the present invention can be peeled from the base material layer and used as a gas barrier film single layer, but is usually used as a laminate in which the gas barrier film is laminated on the base material layer. Such a gas barrier laminate can take various shapes such as a laminate film, a laminate sheet, a tray, a cup, and a hollow body (bottle) depending on the shape of the base material layer and the use.

If the laminated body is a laminated film, the gas barrier laminate obtained by the production method of the present invention is a laminated film suitable as a packaging film that can be heat-sealed by laminating a heat fusion layer on at least one side thereof. Is obtained. As such a heat-fusible layer, a homo- or copolymer of α-olefin such as ethylene, propylene, butene-1, hexene-1, 4-methylpentene-1, octene-1, etc., which are generally known as heat-fusible layers , High pressure method low density polyethylene, linear low density polyethylene (so-called LLDPE), high density polyethylene, polypropylene, polypropylene random copolymer, polybutene, poly-4-methyl pentene-1, low crystalline or amorphous ethylene Polypropylene random copolymer, ethylene / butene-1 random copolymer, polyolefin such as propylene / butene-1 random copolymer, or a composition of two or more, ethylene / vinyl acetate copolymer (EVA), ethylene・ (Meth) acrylic acid copolymer or metal salt thereof, EVA and polyolefin A layer obtained from the object or the like.
Among these, a heat-sealing layer obtained from an ethylene-based polymer such as high-pressure method low-density polyethylene, linear low-density polyethylene (so-called LLDPE), or high-density polyethylene is preferable because it has excellent low-temperature heat sealability and heat seal strength.

  EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist.

The physical property values and the like in Examples and Comparative Examples were obtained by the following evaluation methods.
<Evaluation method>
(1) Polymerization rate [%]: Measured by the method described above.
(2) Oxygen permeability [ml / (m ² · day · MPa)]: Using OX-TRAN 2/21 ML manufactured by Mocon Co., Ltd., according to JIS K 7126, temperature: 20 ° C., humidity: 90 It was measured under the conditions of% RH and 0% RH.
(3) Absorbance ratio (A ₀ / A): measured by the method described above.
(4) Haze [%]: Based on JIS K7136, the haze (%) of one film was measured. A Haze Meter (NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd.) was used as a measuring device.
(5) Water content [% by weight] of coating solution (coating film): 120 × 297 mm measurement sample from laminated film coated with unsaturated carboxylic acid compound polyvalent metal salt solution or laminated film after polymerization After cutting and measuring its weight (Wg), it is dried for 10 minutes in a hot air drier at a temperature of 130 ° C. and its weight (W _dry g) is measured. Separately, a sample for measurement of 120 × 297 mm is cut out from a substrate film (film to which an unsaturated carboxylic acid compound polyvalent metal salt solution is applied), and the weight (W _substrate g) is measured. And the moisture content in a coating film was calculated | required with the following formula | equation using the weight of each said film.
Water content (% by weight) = [(W-W _substrate )-(W _dry- W _substrate )] / (WW _substrate )

<Preparation of solution (X)>
Zinc acrylate (Zn salt of acrylic acid) aqueous solution (manufactured by Asada Chemical Co., Ltd., concentration 30 wt% (acrylic acid component: 20 wt%, Zn component 10 wt%)) and photopolymerization diluted to 25 wt% with methyl alcohol Initiator [1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one (trade name; Irgacure 2959, manufactured by Ciba Specialty Chemicals)] and A surfactant (trade name; Emulgen 120, manufactured by Kao Corporation) was mixed so that the molar fractions were 98.5%, 1.2%, and 0.3%, respectively, and consisted of a Zn acrylate solution (X). An unsaturated carboxylic acid compound polyvalent metal salt solution was prepared.

Example 1
The coating amount of the acrylic acid Zn salt solution (X) is a solid content on a corona-treated surface of a base film made of a biaxially stretched polyester film having a thickness of 12 μm (trade name; Emblet PET12, manufactured by Unitika). After coating to 3.5 g / m ² , immediately using an EB irradiation apparatus (Iwasaki Electric Co., Ltd. model: CB250 / 30/20) with the water content in the coating solution being 28% by weight. Then, a gas barrier laminated film was obtained in which a gas barrier film formed by polymerizing Zn acrylate was irradiated by irradiating an electron beam under the conditions of an acceleration voltage of 110 kV and a dose of 30 kGy.
Polymerization rate [%], oxygen permeability (90% RH and 0% RH) [ml / (m ² · day · MPa)], absorbance ratio (A ₀ / A) and haze [ %] Is shown in Table 1.

Example 2
In the same manner as in Example 1, after applying the Zn acrylate solution (X) to a base film made of a biaxially stretched polyester film, the water content in the coating solution was 44% by weight. A gas barrier laminate film was obtained by irradiating with an electron beam under the same conditions as in FIG.
Polymerization rate [%], oxygen permeability (90% RH and 0% RH) [ml / (m ² · day · MPa)], absorbance ratio (A ₀ / A) and haze [ %] Is shown in Table 1.

Example 3
In the same manner as in Example 1, after applying the Zn acrylate solution (X) to a base film made of a biaxially stretched polyester film, the water content in the coating solution was 54% by weight. A gas barrier laminate film was obtained by irradiating with an electron beam under the same conditions as in FIG.
Polymerization rate [%], oxygen permeability (90% RH and 0% RH) [ml / (m ² · day · MPa)], absorbance ratio (A ₀ / A) and haze [ %] Is shown in Table 1.

Example 4
The coating amount of the above-described Zn acrylate solution (X) is a solid content on a corona-treated surface of a base film made of a biaxially stretched polypropylene film (trade name; OP HE-1 manufactured by Tosero Co., Ltd.) having a thickness of 20 μm. After coating to 3.5 g / m ² , an electron beam was irradiated under the same conditions as in Example 1 with a moisture content in the coating solution of 44% by weight to obtain a gas barrier laminated film. It was.
Polymerization rate [%], oxygen permeability (90% RH and 0% RH) [ml / (m ² · day · MPa)], absorbance ratio (A ₀ / A) and haze [ %] Is shown in Table 1.

Example 5
On the corona-treated surface of a base film made of a 15 μm thick biaxially stretched polyamide film (trade name; Emblem ON15, manufactured by Unitika Ltd.), the coating amount of the acrylic acid Zn salt solution (X) is 3 with a Mayer bar. After coating to 0.5 g / m ² , an electron beam was irradiated under the same conditions as in Example 1 with a moisture content in the coating solution of 44% by weight to obtain a gas barrier laminated film.
Polymerization rate [%], oxygen permeability (90% RH and 0% RH) [ml / (m ² · day · MPa)], absorbance ratio (A ₀ / A) and haze [ %]
Is shown in Table 1.

Reference example 1
The coating amount of the above-described Zn acrylate solution (X) is a solid content on the corona-treated surface of a base film made of a biaxially stretched polyester film (trade name; Emblet PET12, manufactured by Unitika) with a thickness of 12 μm. in after coating to be 3.5 g / ^{m 2,} with moisture content of 28% by weight state in the coating liquid, using a UV irradiation apparatus (eye graphic Co. eYE GRANDAGE model ECS 301G1) immediately, UV A gas barrier laminate film was obtained by polymerizing by irradiation with ultraviolet rays under the conditions of an intensity of 189 mW / cm ² and an integrated light amount of 190 mJ / cm ² .
The polymerization rate [%], oxygen permeability (90% RH) [ml / (m ² · day · MPa)], absorbance ratio (A ₀ / A) and haze [%] of the obtained gas barrier laminate film are shown. It is shown in 2.

Reference example 2
In the same manner as in Reference Example 1, the above-described Zn acrylate solution (X) was applied to a base film made of a biaxially stretched polyester film, and then the temperature; 60 ° C., time; 8 seconds using a hot air dryer Then, the water content of the coating liquid before polymerization is set to 44% by weight, and using a UV irradiation device (EYE GRANDAGE model ECS 301G1 manufactured by Eye Graphic Co., Ltd.), the UV intensity is 189 mW / cm ² , the integrated light quantity is 190 mJ / A gas barrier laminated film was obtained by polymerizing by irradiating ultraviolet rays under the condition of cm ² and laminating the gas barrier film.
The polymerization rate [%], oxygen permeability (90% RH) [ml / (m ² · day · MPa)], absorbance ratio (A ₀ / A) and haze [%] of the obtained gas barrier laminate film are shown. It is shown in 2.

Reference example 3
In the same manner as in Reference Example 1, the above-described Zn acrylate solution (X) was applied to a base film composed of a biaxially stretched polyester film, and then the temperature; 60 ° C., time; 16 seconds using a hot air dryer Then, the water content of the coating liquid before polymerization is set to 54% by weight. Then, using a UV irradiation device (EYE GRANDAGE model ECS 301G1 manufactured by Eye Graphic Co., Ltd.), the UV intensity is 189 mW / cm ² , the integrated light quantity is 190 mJ / Ultraviolet rays were irradiated under the condition of cm ² to obtain a gas barrier laminated film in which a gas barrier film was laminated by polymerization.
The polymerization rate [%], oxygen permeability (90% RH) [ml / (m ² · day · MPa)], absorbance ratio (A ₀ / A) and haze [%] of the obtained gas barrier laminate film are shown. It is shown in 2.

  As can be seen from Table 1 and Table 2, the polyvalent metal salt solution of the unsaturated carboxylic acid compound coated on the base layer is irradiated with an electron beam to polymerize the polyvalent metal salt of the unsaturated carboxylic acid compound. The obtained gas barrier laminate films (Examples 1 to 5) were obtained by irradiating the polyvalent metal salt solution of the unsaturated carboxylic acid compound coated on the base layer with ultraviolet rays to obtain the polyvalent metal salt of the unsaturated carboxylic acid compound. It turns out that it is excellent in oxygen barrier property especially in low humidity (0% RH) compared with the gas barrier property laminated | multilayer film (Reference Examples 1-3) obtained by superposing | polymerizing.

  Since the gas barrier film made of the polymer of the unsaturated carboxylic acid compound polyvalent metal salt of the present invention and the gas barrier laminate formed with such a gas barrier property are excellent in oxygen permeation resistance (gas barrier property), this is required. Taking advantage of the characteristics, it can be suitably used as a packaging material, particularly a food packaging material having a high gas barrier property, as well as various packaging materials such as medical use and industrial use.

Claims (5)

1700 cm in an infrared absorption spectrum comprising a polymer of a polyvalent metal salt of an unsaturated carboxylic acid compound having a degree of polymerization of less than 20 on one surface of a base material layer. ^-1 Absorbance A based on νC = O of nearby carboxylic acid group ₀ And 1520cm ^-1 The ratio of the nearby carboxylate ion to the absorbance A based on νC = O (A ₀ / A) is a gas barrier laminated film excellent in transparency formed by laminating a gas barrier film having 0.10 or less. The gas barrier laminate film having excellent transparency according to claim 1, wherein the haze is 5.3% or less. The gas barrier laminate film according to claim 1 or 2, wherein the unsaturated carboxylic acid compound is an unsaturated carboxylic acid monomer or a polymer having a polymerization degree of 10 or less. An unsaturated carboxylic acid compound is (meth) acrylic acid, The gas-barrier laminated film excellent in transparency in any one of Claims 1-3. The gas barrier laminate film according to claim 1, wherein the polymer of the polyvalent metal salt of the unsaturated carboxylic acid compound having a degree of polymerization of less than 20 is a polymer of zinc (meth) acrylate.