JP2003145690A - Oxygen gas barrier film and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxygen gas barrier film having high oxygen gas barrier properties, capable of developing excellent oxygen gas barrier properties especially even under a high humidity condition and having good sealant adhesiveness, and a method for manufacturing the film having excellent oxygen gas barrier properties from an easily obtainable material at a low cost. SOLUTION: An oxygen gas barrier layer, which comprises a mixture of a polyvinyl alcohol resin (A) with a polymerization degree of 200-2,600 and a saponification value of 90-99.7 mol% and a urethane resin (B), is laminated on at least one surface of a biaxially stretched polypropylene resin film through an adhesive layer to obtain the oxygen gas barrier film. The oxygen permeability of this film under an atmosphere with a temperature of 23 deg.C and a relative humidity of 85% is not more than 1,000 ml/m<2> .day.MPa.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxygen gas barrier film and a method for producing the same, and more particularly to an oxygen gas barrier film suitable for packaging and further as a food packaging film, which is excellent even under high humidity, and a method for producing the same. More specifically, the present invention relates to a film that does not generate hydrogen chloride gas when burned and has excellent oxygen gas barrier properties and sealant adhesion under high humidity, and a method for producing the film.

[0002]

2. Description of the Related Art Conventionally, food and drink, pharmaceuticals, chemicals,
Various resin films are used as packaging materials for filling and packaging various items such as daily sundries.For example, polypropylene films have excellent properties such as processability, transparency, and heat resistance, and are widely used. ing. However,
A high gas barrier property (oxygen barrier property) is required to protect and preserve the quality of these items to be packaged, and packaging materials for products such as foods and pharmaceuticals whose quality deteriorates due to oxygen. It was difficult to apply a polypropylene film having no property.

Therefore, as a means for imparting an oxygen gas barrier property, a material having an oxygen gas barrier property is coated. One of them is a PVDC coated film obtained by coating a polyvinylidene chloride resin (hereinafter sometimes abbreviated as "PVDC") film, which has almost no hygroscopic property and has a good oxygen gas barrier property even under high humidity. Therefore, it is currently used in large quantities.

However, since the PVDC coated film contains chlorine, it has become a problem that it pollutes the global environment by generating toxic hydrogen chloride gas and dioxin by burning. Therefore, there is a strong demand for an oxygen gas barrier film made of a material that does not use chlorine, and its development is being studied.

As such a material having a high oxygen gas barrier property, a polyvinyl alcohol resin (hereinafter referred to as "PVA") is used.
Sometimes abbreviated. ) And ethylene / vinyl alcohol copolymer resin (hereinafter sometimes abbreviated as “EVOH”) are well known. A film coated with such a resin shows an extremely excellent oxygen gas barrier property under low humidity, but since it has a high hygroscopic property, the oxygen gas barrier property decreases as the relative humidity increases, and it is considered to be poor in practicality. It was being done.

Further, Japanese Patent Laid-Open No. 3-30944 discloses "PV
A method of adding a colloidal hydrous layered silicate compound having swelling property to the coating liquid of A ", Japanese Patent No. 27897.
No. 05, "Polyvinyl alcohol modified with at least one colloidal hydrous layered silicate compound having a swelling property and a compound having a silyl group in the molecule".
Is disclosed. However, the films using these all have excellent oxygen gas barrier properties under high humidity, but there is a problem that the cost becomes high.

As described above, at present, a film which can substitute for the PVDC coated film has not yet been obtained due to insufficient oxygen gas barrier property under high humidity and high cost. Further, these films are used by being laminated with a sealant for forming a packaging bag, but there is also a problem that the adhesiveness with the sealant is not sufficient.

[0008]

The conventional oxygen gas barrier film as described above has the above-mentioned problems.

In view of the problems of the conventional oxygen gas barrier film, the present invention selects PVA as an inexpensive material as a substitute for the PVDC-coated biaxially oriented polypropylene resin film, and is a problem of PVA. As a result of diligent studies on improving the oxygen gas barrier property and the sealant adhesive property under high humidity, a biaxially oriented polypropylene resin film was used as a base film, and a specific polyvinyl alcohol resin and urethane were used via an adhesive layer. Oxygen gas barrier property under high humidity and sealant by laminating an oxygen gas barrier layer made of a mixture of system resins and increasing the crystallinity of the oxygen gas barrier layer made of a mixture of a specific polyvinyl alcohol resin and a urethane resin. It was found that the adhesiveness can be greatly improved.

That is, the present invention has a high oxygen gas barrier property,
In particular, an oxygen gas barrier film that can exhibit excellent oxygen gas barrier properties even under high humidity, and has good sealant adhesion, and an oxygen gas barrier property that is easily available and at low cost can be used. It is an object of the present invention to provide a method for producing a film having the same.

[0011]

In order to achieve the above object, the oxygen gas barrier film of the present invention comprises a biaxially stretched polypropylene resin film on at least one surface thereof,
Through the adhesive layer, the degree of polymerization is 200 to 2600, the degree of saponification is 9
An oxygen gas barrier layer composed of a mixture of 0 to 99.7 mol% of a polyvinyl alcohol resin (A) and a urethane resin (B) is laminated, and in an atmosphere of 23 ° C. and a relative humidity of 85%. Oxygen permeability of 1000mL / m
It is characterized in that it is ² · day · MPa or less.

The oxygen gas barrier film of the present invention having the above constitution can exhibit a high oxygen gas barrier property, particularly an excellent oxygen gas barrier property even under high humidity,
Further, it is an oxygen gas barrier film having good sealant adhesion.

In this case, the mixing weight ratio of the polyvinyl alcohol resin (A) and the urethane resin (B) constituting the oxygen gas barrier layer is (A) / (B) = 90/10.
It can be 99.5 / 0.5.

In this case, the crystallinity parameter (CP (M //) ⊥) of the oxygen gas barrier layer can be 0.8 or more.

Here, the crystallinity parameter is the crystallinity parameter (CP (M / M / C) obtained by the polarization ATR spectrum in the infrared polarization ATR method (total reflection measurement method).
/) ⊥), specifically, this crystallinity parameter utilizes the absorption band of polyvinyl alcohol-based resin, and is 1140 for the absorption intensity near 1095 cm ^-1.
It means the ratio of absorption intensity around cm ^-1 .

Furthermore, in this case, the thickness of the oxygen gas barrier layer can be set to 1 μm or less.

In this case, the adhesive layer may be a layer made of acid-modified polyolefin.

Further, in the method for producing an oxygen gas barrier film of the present invention, an unstretched film having an adhesive layer laminated on at least one surface is stretched in one direction, and then a polyvinyl alcohol-based film is applied to the surface of the adhesive layer. An oxygen gas barrier layer made of a mixture of a resin and a urethane resin is formed, and then stretched in a direction perpendicular to the stretching direction.

According to the method for producing an oxygen gas barrier film of the present invention having the above-mentioned constitution, a film exhibiting a high oxygen gas barrier property, particularly an excellent oxygen gas barrier property even under high humidity is produced from an easily available resin. be able to.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the oxygen gas barrier film and the method for producing the same of the present invention will be described below.

The biaxially stretched polypropylene resin film used in the present invention is a known biaxially stretched polypropylene resin film, and its raw materials and mixing ratio are not particularly limited. For example, polypropylene homopolymer (propylene homopolymer), ethylene containing propylene as a main component,
Random copolymers and block copolymers with one or more selected from α-olefins such as butene, pentene and hexene, or a mixture of two or more of these polymers. Good. Antioxidants, antistatic agents, plasticizers, etc. for the purpose of modifying physical properties,
Known additives may be added, for example, petroleum resin, terpene resin, etc. may be added.

The biaxially oriented polypropylene resin film used in the present invention may be of any film thickness depending on the desired purpose such as mechanical strength and transparency. Although not particularly limited, it is usually 10 to 250.
μm is recommended, and the range of use as a packaging material is preferably 15 to 60 μm.

The biaxially oriented polypropylene resin film used in the present invention may be a single layer film,
Alternatively, it may be a laminated film in which a plurality of resin films including a biaxially oriented polypropylene resin film are laminated. Type of laminate when using a laminated film,
The number of layers and the method of layering are not particularly limited, and can be arbitrarily selected from known methods according to the purpose.

In the oxygen gas barrier film of the present invention, the polyvinyl alcohol resin (A) and the urethane resin (B) are provided on at least one surface of such a biaxially stretched propylene resin film with an adhesive layer interposed therebetween. It is necessary that the oxygen gas barrier layer composed of the mixture of 1) is laminated. Without the adhesive layer, the adhesive force between the layer of the biaxially stretched propylene-based resin film and the oxygen gas barrier layer made of a mixture of polyvinyl alcohol-based resin and urethane-based resin would be weakened.

The raw material of the adhesive layer is not particularly limited, but the adhesive layer is preferably made of an adhesive containing an acid-modified polyolefin. For example, a polyolefin-based polymer is (meth) acrylic acid, maleic acid,
Those containing acid-modified polyolefin modified with unsaturated carboxylic acids such as maleic anhydride and fumaric acid are recommended,
In particular, those containing a graft copolymer obtained by graft copolymerizing 0.01 to 5 mol% of maleic acid or maleic anhydride with an olefin polymer are preferably used as the adhesive layer.

Further, the thickness of the adhesive layer is not particularly limited, but the thickness of the adhesive layer is 0.
The thickness is preferably 5 to 5 μm. Further, additives such as an antistatic agent may be added to the adhesive layer depending on the purpose.

A degree of polymerization of 2 is provided on at least one surface of such a biaxially oriented propylene resin film with an adhesive layer interposed.
An oxygen gas barrier layer made of a mixture of polyvinyl alcohol resin (A) and urethane resin (B) having a saponification degree of 0 to 2600 and a saponification degree of 90 to 99.7 mol% is laminated. The polyvinyl alcohol-based resin (A) alone has insufficient sealant adhesion, and the urethane-based resin (B) alone
The oxygen gas barrier property under high humidity is insufficient. Preferably, the mixing weight ratio of the polyvinyl alcohol resin (A) and the urethane resin (B) is (A) / (B) = 90/10.
˜99.5 / 0.5.

The degree of polymerization and the degree of saponification of the polyvinyl alcohol resin (A) used in the present invention depend on the desired characteristics of the film, particularly the oxygen gas barrier property and the P during film production.
It is determined from the viscosity of the VA aqueous solution and the stretchability of the coat layer after coating. Regarding the stretchability, the higher the degree of polymerization, the slower the degree of crystallization and the better the stretchability. However, if the degree of polymerization is too high, the coating becomes difficult because the viscosity of the aqueous solution is high and gelation easily occurs. Therefore, it is necessary that the degree of polymerization is 200 or more from the viewpoint of the stretchability of the coat layer and 2600 or less from the viewpoint of coating workability. It is preferably 500 to 2000. Regarding the degree of saponification, if it is less than 90%, the required oxygen gas barrier property under high humidity cannot be obtained, and if it exceeds 99.7%, it is difficult to prepare an aqueous solution and it easily gels, which is not suitable for industrial production. Therefore, the saponification degree is required to be 90 to 99.7%, preferably 93 to 99%.

On the other hand, the urethane resin (B) is preferably a water-soluble or water-dispersible urethane resin because of its miscibility with the polyvinyl alcohol resin, and a polyol compound,
It is produced by subjecting a hydrophilic group-containing polyol compound and a polyisocyanate component to a polyaddition reaction by a known method.

As the polyol compound, ethylene glycol, propylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,4- Bis (hydroxymethyl) cyclohexane, bisphenol A, hydrogenated bisphenol A, hydroxypivalic acid neopentyl glycol ester, trimethylolethane, trimethylolpropane, pentaerythritol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol,
Polyether such as silicone-modified polyether and urethane-modified polyether, epoxy resin-modified polyol, polycarbonate diol, acrylic polyol, polybutadiene polyol and the like can be used alone or in combination of two or more kinds.

A hydroxyl group-containing polyester resin can also be used as the polyol compound. The hydroxyl group-containing polyester resin is obtained by a polycondensation reaction of a polycarboxylic acid compound and a polyol compound, and is obtained by making the polyol compound excessive with respect to the polycarboxylic acid compound. As the polycarboxylic acid compound, succinic acid, adipic acid,
Sebacic acid, azelaic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic anhydride, tetrahydrophthalic acid, hexahydrophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, dimer acid, trimellitic acid, pyromellitic acid , Ε-caprolactone and the like can be used alone or in combination of two or more, and maleic acid containing a reactive unsaturated bond, fumaric acid, citaconic acid, chloromaleic acid, allyl succinic acid, mesaconic acid and It is not possible to use those anhydrides and the like. The same polyol compound as described above can be used as the polyol compound.

Examples of the hydrophilic group-containing polyol compound include glyceric acid, glycolic acid, lactic acid, malic acid, dihydroxytartaric acid, 2,2-dimethylolvaleric acid, 2,2-dimethylolpropionic acid propionic acid and dimethylolbutanoic acid. It is used, especially from the economical point of view.
Preference is given to using 2-dimethylolpropionic acid and dimethylolbutanoic acid.

As the polyisocyanate compound, for example, tolylene diisocyanate, diphenylmethane-
Aroma such as 4,4-diisocyanate, xylylene diisocyanate, naphthalene-1,5-diisocyanate, p-phenylene diisocyanate, dibenzyl diisocyanate, diphenyl ether diisocyanate, m- or p-tetramethyl xylylene diisocyanate, or triphenylmethane triisocyanate. Group di- or triisocyanate compounds, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane-4,4-diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, or isophorone Aliphatic or alicyclic diisocyanates such as diisocyanate are used. Examples of trifunctional or higher polyisocyanate compounds based on these various monomers include polyisocyanurate type polyisocyanates, and various modified polyisocyanates such as burette type polyisocyanates.

The crystallinity parameter (CP (M //) ⊥) obtained by the deflection ATR spectrum of the oxygen gas barrier layer made of a mixture of the polyvinyl alcohol resin (A) and the urethane resin (B) in the present invention is 0. It is preferably 0.8 or more. Crystallinity parameter (CP (M
If the value of //) ⊥) is 0.8 or more, excellent oxygen gas barrier properties can be exhibited even under high humidity.

In the present invention, the crystallinity parameter is a value measured by the infrared polarization ATR method (total reflection measurement method) for the oxygen gas barrier layer of the oxygen gas barrier film,
Specifically, the crystallinity parameter (CP (M //) obtained by the polarized ATR spectrum in the infrared polarized ATR method was used.
⊥). When the crystallinity of polyvinyl alcohol resin is evaluated by IR spectrum, it is usually 11
It is evaluated by the absorption intensity near 40 cm ^-1, but it is infrared polarized AT
Since the spectral absorption intensity by the R method is strongly influenced by the measurement area, thickness and surface condition of the sample, it is preferably evaluated by the relative intensity with other absorption intensities. Therefore, the crystallinity parameter in the present invention is 1095 cm ^−1.
The ratio of the absorption intensity in the vicinity of 1140 cm ^{-1 to} the absorption intensity in the vicinity was defined. The higher the crystallinity parameter (CP (M //) ⊥), the more excellent the oxygen gas barrier property is obtained. Therefore, it is preferably 1.0 or more, more preferably 1.2 or more, and most preferably 1.9 or more. Is.

As a method for laminating the oxygen gas barrier layer made of a mixture of polyvinyl alcohol resin and urethane resin, a coating method is particularly preferable. The coating method is not limited, but an optimum method may be selected depending on the coating amount and viscosity of the coating liquid used. A reverse roll coating method, a roll knife coating method, a die coating method or the like may be adopted.

The conditions of drying and heat treatment during coating depend on the thickness of the coating and the conditions of the apparatus, but they are immediately sent to the drawing process in the perpendicular direction without a drying process and dried in the preheating zone or drawing zone of the drawing process. Preferably. In such a case, it is usually performed at about 80 to 170 ° C. If necessary, a corona discharge treatment is performed on the polypropylene resin film before forming the oxygen gas barrier layer made of a mixture of polyvinyl alcohol resin and urethane resin,
Other surface activation treatment or anchor treatment using a known adhesive may be performed. Further, it is an object of the present invention to add various known inorganic and organic additives such as an antistatic agent, a slip agent, and an antiblocking agent in an oxygen gas barrier layer composed of a mixture of polyvinyl alcohol resin and urethane resin. It is optional unless it inhibits.

The thickness of the oxygen gas barrier layer made of a mixture of polyvinyl alcohol resin and urethane resin varies depending on the polypropylene resin film and the required oxygen gas barrier property, but the minimum thickness for exerting the oxygen gas barrier property is good, Usually, a dry thickness of 1 μm or less is preferable in terms of transparency, handleability, and economy.

In the oxygen gas barrier film of the present invention, a heat sealable resin layer called a sealant is usually laminated on an oxygen gas barrier layer made of a mixture of polyvinyl alcohol resin and urethane resin. The heat-sealable resin layer is usually formed by an extrusion laminating method or a dry laminating method.

The thermoplastic polymer for forming the heat-sealable resin layer used in the present invention may be any one as long as it can sufficiently exhibit sealant adhesiveness, such as HDPE and LDP.
E, polyethylene resin such as LLDPE, PP resin,
An ethylene-vinyl acetate copolymer, an ethylene-α olefin random copolymer, an ionomer resin, etc. can be used. In general, it is preferable that the heat seal resin is not a chlorine-containing resin in view of environmental problems during incineration treatment.

According to the present invention, it is inexpensive and has excellent oxygen gas barrier property and sealant adhesive property under high humidity, and further, does not contain dioxin and hydrogen chloride gas in the incineration exhaust gas. Can provide a film that is effective.

[0042]

EXAMPLES The present invention will now be specifically described with reference to the following examples and comparative examples, but the present invention is not limited to these. The concentration in the liquid is displayed on a weight basis unless otherwise specified, and the characteristic value evaluation was performed by the following method.

(1) Oxygen permeability The oxygen permeability is "MOCON OX-TRA" manufactured by Modern Control.
N 2/20 ”was used, and the measurement time was 30 minutes in an atmosphere controlled at 23 ° C. and a relative humidity of 85%. The unit of oxygen permeability is mL / m ² · day · MPa.

(2) Lamination Strength Lamination strength is obtained by using a polyether polyurethane polyurethane adhesive (trade name: Toyo Morton Co., Ltd.) as a laminating adhesive on the surface of an oxygen gas barrier layer composed of a mixture of polyvinyl alcohol resin and urethane resin. : Ad Court)
The after 3 g / m ² coating, cast polypropylene film (thickness 40 [mu] m, manufactured by Toyobo Co., Ltd.: P1128) bonding the corona discharge treated surface of the performs 72 hours aging at 40 ° C., to obtain a laminate film. The strength of this laminated film (15 mm width) when peeled at 90 ° at room temperature is shown.

(3) Crystallinity parameter Bio-Rad FT-IR (FTS-60A / 896) ATR measurement accessory (Perkin-Elmer), polarizer and internal reflection having symmetrical edges Element (Ge, incident angle 4
The crystallinity of each test piece (length 45 mm x width 17 mm) was measured by the infrared polarization ATR method using an ATR device equipped with 5 degrees, thickness 2 mm x length 50 mm x width 20 mm). In addition, the infrared light at the end portions was blocked so that the infrared light was incident only on the central portion (width 12 mm) of the internal reflection element.

The test piece has a lengthwise direction taken in the width direction of the film (a direction perpendicular to the flow direction), and an oxygen gas barrier layer made of a mixture of polyvinyl alcohol resin (A) and urethane resin (B) is provided. Internal Reflection Elem
The measurement was performed by bringing the reflective surface of the test piece into contact with ent and irradiating it with vertically polarized light. Spectra obtained spectrum
rum (M //) ⊥

In the obtained polarized ATR spectrum,
1140cm Request absorption and 1095 cm ^-1 vicinity absorbance of absorption of around ^-1. At this time, a peak portion near 1140 cm ⁻¹ in the polarized ATR spectrum and a valley portion on the high wave number side are
The line connecting the two points of the valley on the low wave number side of the peak near 5 cm ^-1 is used as the baseline, and the height from the baseline to the peak of the absorption band is the polyvinyl alcohol resin (A) and the urethane resin (B ) Is the absorbance of the oxygen gas barrier layer absorption band consisting of a mixture of The absorbance of the peak near 1140 cm ^-1 is A1140 and the absorbance of the peak near 1095 cm ^-1 is A1095. When no clear peak was observed, the absorbances at the positions of 1140 cm ⁻¹ and 1095 cm ⁻¹ were A1140 and A1095.

For the spectrum of Spectrum (M //) ⊥, the ratio of A1140 to A1095 (A114
0 / A1095) was calculated. This value is used as a crystallinity parameter and is shown by CP (M //) ⊥.

(Example 1) Preparation of coating liquid 900 g of an aqueous solution containing 7% of isopropyl alcohol
While stirring, 97 g of polyvinyl alcohol-based resin (saponification degree: 98.5 mol%, polymerization degree: 1000) powder was gradually added to the aqueous solution. After heating to about 80 ° C. to completely dissolve it, it was cooled to 40 ° C. Then, 3 g of a solid content of the water-dispersed polyester urethane resin (a) was added.

Coating on film and evaluation Polypropylene resin 9 as polypropylene resin layer
A resin obtained by mixing 3% by weight of a petroleum resin (ESCOLETS E5300: manufactured by Tonex Co.) containing substantially no polar group in 7% by weight, an acid-modified polyolefin as an adhesive layer, a polypropylene resin film layer / adhesive layer = 19 / 1
The resin layer was coextruded in a two-layer state at a ratio of (weight ratio) to a resin temperature of 260 ° C., cast with a casting roll at a temperature of 25 ° C., and then stretched 4 times in the longitudinal direction to obtain a film having a thickness of 180 μm I got a film. Next, after applying the coating liquid on the adhesive layer surface of the obtained laminated film by the reverse roll coating method, it was stretched 9 times in the transverse direction. The oxygen permeability and the crystallinity parameter of this coated film were measured.

Next, a polyether type polyurethane adhesive (manufactured by Toyo Morton Co., Ltd .:
After applying 3 g / m ^{2 of a} product name: ADCOAT, it is laminated with a corona-treated surface of an unstretched polypropylene film (thickness 40 μm, manufactured by Toyobo Co., Ltd .: P1128), 4
Aging was performed at 0 ° C. for 72 hours to obtain a laminated film. The laminate strength of this laminate film was evaluated.

(Examples 2 and 3, Comparative Examples 4 and 5) Samples were produced in the same manner as in Example 1 except that the degree of polymerization of the polyvinyl alcohol resin in the coating solution was changed as shown in Table 1. An evaluation was made.

(Examples 4 and 5, Comparative Examples 6 and 7) Samples were prepared in the same manner as in Example 1 except that the saponification degree of the polyvinyl alcohol resin in the coating solution was changed as shown in Table 1. An evaluation was made.

Example 6 A sample was prepared in the same manner as in Example 1 except that the urethane resin of the coating solution was changed to the water-dispersed polyether urethane resin (b) as shown in Table 1. An evaluation was made.

(Examples 7 and 8 and Comparative Example 8) Samples were prepared in the same manner as in Example 1 except that the mixing ratio of the polyvinyl alcohol resin and the urethane resin in the coating liquid was changed as shown in Table 1. And evaluated.

Comparative Example 1 A sample was prepared and evaluated in the same manner as in Example 1 except that the coating liquid was directly applied to the biaxially oriented polypropylene resin film on which the adhesive layer was not laminated.

(Comparative Example 2) The coating solution was prepared by mixing the urethane resin with the polyvinyl alcohol resin (saponification degree: 9).
A sample was manufactured and evaluated in the same manner as in Example 1 except that only 8.5 mol% and a polymerization degree of 1000) were used.

(Comparative Example 3) A sample was prepared and evaluated in the same manner as in Example 1 except that the coating liquid used was not a polyvinyl alcohol resin but only a urethane resin. It was

Comparative Example 9 An isocyanate adhesive was dried as an adhesive on the corona discharge treated surface of a biaxially stretched polypropylene resin film having a thickness of 20 μm, and the coating amount was 3
Gravure coating was performed so as to be g / m ² . The same coating liquid as in Example 1 was gravure-coated on the anchor layer to give 1
It dried at 40 degreeC and the laminated film was obtained.

Table 1 shows the coating compositions and evaluation results of the above Examples and Comparative Examples.

[0061]

[Table 1]

[0062]

EFFECTS OF THE INVENTION According to the oxygen gas barrier film of the present invention, it is possible to exhibit a high oxygen gas barrier property, in particular, an excellent oxygen gas barrier property even under high humidity, and a good sealant adhesive property.

Further, according to the method for producing an oxygen gas barrier film of the present invention, it can be produced from easily available materials at low cost.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsuya Ito             2-1-1 Katata, Otsu City, Shiga Prefecture Toyobo             Koki Co., Ltd. (72) Inventor Ishi Nakatani             344 Maebata, East Inuyama, Inuyama City, Aichi Prefecture             Inuyama Factory, Yobo Co., Ltd. (72) Inventor Ichiro Kitaura             344 Maebata, East Inuyama, Inuyama City, Aichi Prefecture             Inuyama Factory, Yobo Co., Ltd. (72) Inventor Yutaka Matsumura             344 Maebata, East Inuyama, Inuyama City, Aichi Prefecture             Inuyama Factory, Yobo Co., Ltd. F term (reference) 4F100 AK03G AK07A AK21B AK51B                       AL05B AL06G BA02 EH20                       EJ38A GB15 JA11B JD03                       JD04 JL11 YY00 YY00B                 4J002 BE02W CK02X GF00 GG02

Claims (6)

[Claims] 1. A polymerization degree of 2 is provided on at least one surface of a biaxially oriented polypropylene resin film with an adhesive layer interposed therebetween.
An oxygen gas barrier layer made of a mixture of polyvinyl alcohol resin (A) and urethane resin (B) having a saponification degree of 90 to 29.7 and a saponification degree of 90 to 99.7 mol%, and
An oxygen gas barrier film having an oxygen permeability of not more than 1000 mL / m ² · day · MPa in an atmosphere of 23 ° C. and a relative humidity of 85%. 2. A mixing weight ratio of the polyvinyl alcohol resin (A) and the urethane resin (B) constituting the oxygen gas barrier layer is (A) / (B) = 90/10 to 99.5 /.
It is 0.5, The oxygen gas barrier film of Claim 1 characterized by the above-mentioned. 3. The oxygen gas barrier film according to claim 1 or 2, wherein the oxygen gas barrier layer has a crystallinity parameter (CP (M //) ⊥) of 0.8 or more. 4. The oxygen gas barrier film according to claim 1, 2 or 3, wherein the oxygen gas barrier layer has a thickness of 1 μm or less. 5. The oxygen gas barrier film according to claim 1, wherein the adhesive layer is made of an acid-modified polyolefin. 6. The method for producing an oxygen gas barrier film according to claim 1, 2, 3, 4 or 5, wherein an unstretched film having an adhesive layer laminated on at least one surface is stretched in one direction. Then, an oxygen gas barrier layer made of a mixture of polyvinyl alcohol resin (A) and urethane resin (B) is formed on the surface of the adhesive layer, and then stretched in a direction perpendicular to the stretching direction. A method for producing an oxygen gas barrier film.