JP3892246B2 - Method for producing gas barrier film - Google Patents

Description

【００３４】
表−１におけるコーテイング樹脂（ａ），（ｂ）,（ｃ）は以下の通りである。
＜水溶性アクリル樹脂（ａ）＞
アクリル1：日本純薬（株）製『ジュリマーＦＣ−８０』（配合量は固形分濃度３０％として計算）
＜水溶性ウレタン樹脂（ｂ）＞
ウレタン1：ゼネカ（株）製『ＮｅｏＲｅｚ Ｒ−９６０３』（配合量は固形分濃度３４％として計算）
ウレタン2：大日本インキ化学工業（株）製『ハイドラン ＡＰ−３０』（配合量は固形分濃度２０％として計算）
＜ポリビニルアルコール（ｃ）＞
PVA1：日本合成化学工業（株）製『ゴーセノールＮ−３００（重合度１６５０〜１７００ 鹸化度９８〜９９ｍｏｌ％）』
PVA2：日本合成化学工業（株）製『ゴーセノールＧＭ−１４（重合度１６５０〜１７００ 鹸化度８６.５〜８９ｍｏｌ％）』
上記PVA1,PVA2（顆粒状）の水への溶解方法は同製品のカタログを参照し、（ｃ）を溶解させた水溶液に（ａ）液と（ｂ）液を追加して水溶性樹脂コーティング液を調整した。
【００３５】
【表２】

【００３６】
【発明の効果】
本発明により得られる、ガスバリア性フィルム、即ち、無機酸化物薄膜が蒸着されたポリプロピレン系樹脂成形品は、低湿側のみならず高湿側でもガスバリア性に優れ、更に、これの二次加工時や使用時に金属酸化物薄膜が剥離してガスバリア性が低下するようなことがなく、併せて透視性、耐溶剤性に優れるので、ＰＶＤＣコートＯＰＰに代わる安価な包装材料として食品、工業用品及び医薬品等を保護するために用いられる包装用樹脂成形品として広く供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a gas barrier film having excellent oxygen gas barrier properties, water vapor barrier properties, transparency, solvent resistance, and laminate strength, which is used for protecting foods, industrial articles, pharmaceuticals, and the like.
[0002]
[Prior art]
Many gas barrier films and packaging materials using the same are already known. Aluminum foil has the most perfect gas barrier property, but it has a low pinhole strength by itself and cannot be used except for special cases, and is almost used as an intermediate layer of a laminate film. The gas barrier property of this laminate film is almost perfect, but there are drawbacks such as the fact that the contents cannot be seen due to the opaqueness, and that it is difficult to determine whether the heat sealing has been reliably performed.
[0003]
As another gas barrier film, a polyvinylidene chloride (hereinafter “PVDC”) film and a coating film are well known. In particular, a coating film of PVDC is well known, and is frequently used as a base film for lamination when oxygen and water vapor barrier properties are required. Since PVDC has almost no hygroscopic property and has a good gas barrier property even under high humidity, various substrates are used regardless of moisture permeability. For example, films such as biaxially stretched polypropylene (OPP), biaxially stretched nylon (ONy), biaxially stretched polyester (in the case of biaxially stretched polyethylene terephthalate (OPET)), and cellophane are used. The laminated film makes use of gas barrier properties and is used for various food packaging regardless of whether it is dry or water. However, after these packaging materials are used, they are discarded as household waste from households. However, since PVDC generates hydrogen chloride gas by combustion, there is a strong demand for the transition to other materials.
[0004]
On the other hand, as a gas barrier film, a metal film such as aluminum or aluminum oxide or silicon oxide is vapor-deposited on a plastic film, and food, industrial goods, pharmaceuticals, etc. are wrapped in a container and the contents are controlled by suppressing oxygen permeation. It has been proposed to prevent oxidation and to maintain the quality for a long time. For example, in Japanese Patent Publication No. 53-12953 and Japanese Patent Application Laid-Open No. 4-353532, a general formula SixOy (x) is formed on at least one surface of a flexible plastic film such as polyethylene terephthalate, cellophane, nylon, polypropylene, polyethylene, etc. = 1, 2, y = 0, 1, 2, 3) A transparent flexible film having a high degree of air resistance and moisture resistance provided with a transparent glassy thin film layer having a thickness of 100 to 3000 angstroms of silicon oxide composition A plastic film is disclosed.
[0005]
Of these, generally, when the film material is a resin having a polar group such as polyester, nylon, and cellophane, the adhesion strength between the film and the inorganic oxide film is generally high, and the gas barrier property is also good. However, even if a vapor-deposited film made of an inorganic oxide is formed on the surface of a film such as polypropylene that does not have a polar group, a stable gas barrier property that can withstand practical use cannot be obtained. That is, since the adhesion between the polypropylene film and the deposited film is not sufficient, when laminating a heat-sealable resin to impart heat sealability to the deposited product, the laminate is used for bag making and lid sealing. When secondary processing is performed, when these bags are used, the contents are filled in the container, or when boil and retort are sterilized, external stress and heat are applied to the molded product, and the inorganic oxide thin film becomes a polypropylene film. There is a problem that the film is more peeled, the gas barrier property is lowered, and cannot be practically used.
[0006]
For example, as described in JP-A No. 2000-263722, such a problem tends to be improved by using an organic solvent-based resin coating solution such as ethyl acetate, toluene, and methyl ethyl ketone. However, environmental problems, effects on the human body, In view of cost and the like, development of a water-based coating agent is desired. JP-A-7-126419 and JP-A-8-245816 show examples in which a metal or inorganic compound is deposited after a water-soluble resin coating solution containing polyvinyl alcohol (PVA) is applied to a polypropylene film. . However, in these examples, since the resin component forming the coating layer after drying is mainly composed of polyvinyl alcohol, even if the oxygen barrier performance on the low humidity side is good, the barrier performance is significantly lowered on the high humidity side. Furthermore, problems such as insufficient adhesion strength between the polypropylene film and the coating layer or between the coating layer and the deposited thin film layer remain.
Japanese Patent Application Laid-Open No. 8-92400 discloses a case where an ethylene / vinyl alcohol copolymer (hereinafter referred to as “EVOH”) is used instead of PVA. In the case of EVOH, barrier properties under high humidity are also disclosed. However, on the other hand, the adhesion between the olefinic resin layer and the AC layer is lowered, which does not satisfy both the gas barrier property and the adhesion.
[0007]
[Problems to be solved by the invention]
The present invention is based on the present state of the gas barrier film as described above, and is an inexpensive packaging material that replaces PVDC-coated OPP (so-called K-OP). It is a gas barrier film coated with an agent and deposited with an inorganic oxide thin film, which has excellent gas barrier properties not only on the low-humidity side but also on the high-humidity side. In addition, the inorganic oxide thin film peels off during secondary processing and use. It is an object of the present invention to provide a gas barrier film that does not deteriorate gas barrier properties and is excellent in transparency and solvent resistance.
[0008]
[Means for Solving the Problems]
The present invention has been achieved as a result of diligent investigations for the above-mentioned purpose, and an unstretched film obtained by melt-extrusion of a polypropylene resin is stretched in the machine direction, subjected to corona discharge treatment, and then The corona-treated surface of the longitudinally stretched film comprises a water-soluble acrylic resin (a), a water-soluble urethane resin (b), and polyvinyl alcohol (c), and the weight ratio in solid content is represented by the following formulas (1) to (3). The present invention relates to a method for producing a gas barrier film, characterized in that a water-soluble resin coating solution satisfying the above condition is applied and stretched in the transverse direction, and then an inorganic oxide vapor deposition film is formed on the coating surface.
[Formula 2]
50 wt% ≦ (a) + (c) ≦ 70 wt% (1)
30 wt% ≤ (b) ≤ 50 wt% (2)
1 ≦ (a) / (c) ≦ 3 (3)
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail. In the present invention, a specific water-soluble coating solution is applied to a polypropylene base film by a so-called in-line coating method and stretched, and finally an inorganic oxide is deposited. Good gas barrier properties can be obtained by combining a water-soluble acrylic resin (a), polyvinyl alcohol (c) and an inorganic oxide. In addition, by combining the water-soluble urethane resin (b) and the polyvinyl alcohol (c), a strong bond between the hydroxyl group or peroxide group on the corona discharge-treated polypropylene surface and the polar group contained in the (b) or (c) And a strong bond between the inorganic atom or oxygen atom in the deposited thin film and the polar group contained in (b) or (c) is obtained, and finally the sufficient adhesion strength between the substrate and the deposited inorganic oxide film is obtained. can get.
[0010]
The polypropylene resin for the base material layer is a propylene resin such as propylene homopolymer, propylene / ethylene copolymer, propylene / butene-1 copolymer, propylene / 4-methylpentene-1 copolymer, branched low density polyethylene, etc. An ethylene resin such as linear polyethylene or a polypropylene resin modified with an α, β-unsaturated carboxylic acid can be used. Two or more of these may be used in combination, or may be used in a stacked manner. Further, depending on the purpose, lubricants, antioxidants, ultraviolet absorbers, antistatic agents, antiblocking agents, antibacterial agents, nucleating agents, and the like may be contained from a very small amount to several tens of percent.
[0011]
The water-soluble acrylic resin (a) used in the water-soluble resin coating solution is not particularly limited, but in terms of wettability, the colloidal dispersion type or the water-soluble type has a smaller particle diameter than the emulsion type. preferable. Specifically, hydroxyl groups such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and 3-hydroxypropyl (meth) acrylate are used. Or a water-dispersed (co) polymer containing one or more monomer units selected from those having an epoxy group such as glycidyl (meth) acrylate. (Meth) acrylic acid-based monomer units such as (meth) acrylamide, (meth) acrylic acid, (meth) acrylic acid soda, and (meth) acrylic acid potassium may be included. Moreover, you may use together and use 2 or more types of the (co) polymer from which a structural component differs.
[0012]
The water-soluble acrylic resin (a) contributes to oxygen barrier properties together with polyvinyl alcohol (c) described later, and both are preferably 50 to 70 wt% in terms of the weight ratio of the solid content. If it is less than 50 wt%, sufficient gas barrier performance cannot be obtained. Conversely, if it exceeds 70 wt%, the gas barrier performance is good, but the solvent resistance in printing on an inorganic oxide vapor-deposited film is poor.
[0013]
The blending ratio of the water-soluble acrylic resin (a) and the polyvinyl alcohol (c) is preferably 1 ≦ (a) / (c) ≦ 3 in terms of the weight ratio of the solid content, and the ratio of (a) / (c) If the value is less than 1, it becomes the main component of polyvinyl alcohol (c), which not only deteriorates the oxygen barrier property on the high humidity side, but also causes peeling at the time of boil / retort heating in bag-made products. On the other hand, if it exceeds 3, sufficient adhesion strength between the substrate and the inorganic oxide vapor deposition film cannot be obtained.
[0014]
The water-soluble urethane resin (b) used in the water-soluble resin coating liquid is not particularly limited, but is preferably a dispersion type, aliphatic or aromatic polyether urethane, aliphatic or aromatic polyester urethane, Aliphatic or aromatic polycarbonate urethane can be used. One or two or more of these may be used in combination.
The water-soluble urethane resin (b) contributes to solvent resistance and is preferably 30 to 50 wt% in terms of the weight ratio of the solid content concentration. If it is less than 30 wt%, not only the solvent resistance in the case of printing on an inorganic oxide vapor-deposited film will be inferior, but also the effect of suppressing bleed from the substrate will be weak. On the other hand, if it exceeds 50 wt%, not only a sufficient gas barrier performance cannot be obtained, but also the resin coating film becomes hard.
[0015]
The polyvinyl alcohol used in the water-soluble resin coating liquid is not particularly limited, but the polymerization degree is 300 to 2000 and the saponification degree is 85 to 85 from the viewpoint of the viscosity of the coating liquid and the oxygen barrier property of the coating film containing polyvinyl alcohol. What is 99.5 mol% is preferable.
The solid content concentration in the above water-soluble resin coating solution is not particularly limited as long as it can be uniformly applied, but is usually 1 to 10 wt%, preferably 2 to 5 wt%. In addition, you may add suitably various additives, such as an antifoamer, an emulsifier, an antistatic agent, an antiblocking agent, a viscosity modifier, to this water-soluble resin coating liquid according to the objective.
[0016]
Application of the water-soluble resin coating liquid to the substrate is, for example, a spray coating method, an air knife coating method, a metering bar coating method, a Mayer bar coating method, a gravure roll coating method, a reverse roll coating method, a kiss roll coating method, or Various coating methods based on these combinations can be employed. When it is difficult to maintain the proper viscosity of the water-soluble resin coating liquid, or when uniform application is difficult, the coating liquid may be heated to, for example, 30 to 90 ° C.
[0017]
The coating thickness is usually in the range of 10 to 60 μm in terms of WET film thickness, and is usually 0.01 to 2 μm, preferably 0.03 to 1 μm in the state of being rolled up after transverse stretching and heat setting. Selected as If the thickness is less than 0.01 μm, the surface of the polypropylene resin with severe irregularities cannot be sufficiently smoothed, and therefore sufficient oxygen barrier properties cannot be obtained. Moreover, the effect which suppresses the bleed material etc. from a base material will become weak. On the other hand, when it becomes thicker than 2 μm, when it is wound up in a roll shape, it is not only easy to cause blocking, but also the cost becomes high.
[0018]
The stretched film before vapor deposition in the present invention is produced as follows. That is, the polypropylene-based resin is melt-extruded into a single-layer or multi-layer film, and the unstretched film is heated to 120 to 140, and usually 3 to 8 times in the vertical direction using the difference in peripheral speed of the roll group. After stretching, a corona discharge treatment is performed, a water-soluble resin coating solution is applied to the corona-treated surface of the longitudinally stretched film, and it is usually stretched 4 to 12 times in the transverse direction with a tenter, and heat-fixed as necessary. In general, the film is manufactured by trimming both ends of the film and winding it into a roll.
[0019]
The amount of the corona discharge treatment is usually 30 to 100 w · min / m ² . If it is less than 30 w · min / m ² , it is difficult to sufficiently modify the surface of the polypropylene resin, and sufficient adhesion strength with the water-soluble resin coating solution cannot be obtained. On the other hand, if it exceeds 100 w · min / m ² , the discharge spark becomes large, and when a whitening streak pattern is formed on the coating film, this causes uneven coating. The surface tension level of the corona discharge treated film surface is 35 dynes / cm or more, preferably 40 to 50 dynes / cm.
[0020]
The stretched film is preferably a biaxially stretched polypolypropylene film having a base layer thickness of 10 to 100 μm and a uniaxially stretched film of a water-soluble resin coating liquid film having a thickness of 0.01 to 2 μm on at least one surface. Is a laminated structure. Further, the transparency is good, and the total light transmittance of the film is usually 85% or more, preferably 90% or more.
[0021]
An inorganic oxide is deposited on the coating surface of the above stretched film. The inorganic oxide in this case is a metal, non-metal, or sub-metal oxide, and specific examples include aluminum oxide, zinc oxide, antimony oxide, indium oxide, calcium oxide, cadmium oxide, silver oxide, and gold oxide. , Chromium oxide, silicon oxide, cobalt oxide, zirconium oxide, tin oxide, titanium oxide, iron oxide, copper oxide, nickel oxide, platinum oxide, palladium oxide, bismuth oxide, magnesium oxide, manganese oxide, molybdenum oxide, vanadium oxide, Although barium oxide etc. are mentioned, a silicon oxide and aluminum oxide are especially preferable at the point which has high oxygen gas barrier property, water vapor | steam barrier property, and transparency, and is industrially cheap. Such silicon oxide and aluminum oxide may be used alone or as a mixture. The inorganic oxide may contain trace amounts of metals, non-metals, sub-metals or their hydroxides, and carbon or fluorine as appropriate for the purpose of improving flexibility.
[0022]
For the formation of the deposited film, a vacuum deposition method is preferable from the viewpoint of film uniformity and adhesion to the substrate, and examples thereof include a resistance heating method, a high frequency induction heating method, and an electron beam method. When silicon oxide is formed by a vacuum deposition method, a reactive deposition method in which SiO, SiO ₂ , or a mixture thereof, and a mixture of Si and SiO ₂ are employed as an evaporation source material and oxygen gas is supplied simultaneously. Can also be adopted. In addition, when aluminum oxide is formed by vacuum deposition, aluminum oxide powder or solid material is adopted as a deposition source material. However, reactive vapor deposition using an aluminum metal with oxygen gas introduced is preferred. It is more preferable in that an amorphous and flexible aluminum oxide thin film layer can be formed. Although there is no restriction | limiting in particular in the thickness of a vapor deposition film, Although it changes also with kinds, etc. of inorganic oxides, from points, such as oxygen gas barrier property and water vapor | steam barrier property, transparency, and cost, Usually 50-2000angstrom, Preferably it is 100-500angstrom. It is.
[0023]
The gas barrier film obtained by the production method of the present invention may be used as it is depending on the application, or a heat seal layer or a protective layer may be further provided on the deposited film. The heat seal layer is not particularly limited, and is usually unstretched polypropylene, polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, or ethylene-vinyl acetate copolymer, ethylene-acrylic acid system. And ethylene ionomers such as copolymers. The heat seal layer is usually provided by a dry lamination method or an extrusion method. The thickness is usually 20 to 100 μm, preferably 40 to 80 μm. The protective layer is provided by laminating a film of polyester, nylon, ethylene-vinyl alcohol copolymer, or by coating with a heat-resistant epoxy resin, melamine resin, urethane resin, polyester resin, or the like. It is done.
[0024]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this does not specifically limit the scope of the present invention.
The film obtained in the following examples was evaluated by the following method. Note that the laminate film means that an unstretched polypropylene film having a thickness of 50 μm is dry-laminated using a two-component curable polyurethane adhesive on the inorganic oxide thin film surface of the gas barrier film of the present invention at 40 ° C. It means a resin molded product that has been aged for 3 days and has a gas barrier property provided with a heat seal layer.
[0025]
<MFR [g / 10 min]>
Measured according to JIS K-6758 at a load of 2160 g and a measurement temperature of 190 ° C. <Thickness of water-soluble resin coating layer [μm]>
The cross section of the wound stretched film was observed with a transmission electron microscope (H-600 type manufactured by Hitachi, Ltd.) and measured.
<Thickness of deposited film [Angstrom]>
Using a fluorescent X-ray apparatus manufactured by Rigaku Denki Kogyo Co., Ltd., the thickness of the deposited film as Si was measured.
<Total light transmittance [%] and haze>
It measured using the Nippon Denshoku Industries haze meter NDH300A type.
<Yellowness>
Measurement was performed using a color difference meter Z-Σ80 manufactured by Nippon Denshoku Industries Co., Ltd.
<Solvent resistance>
Using a cotton swab soaked with ethyl acetate, the surface of the inorganic oxide thin film was rubbed lightly 5 times in a fixed direction, and the peeling state of the inorganic oxide thin film was observed with an optical microscope (200 times). Judged.
○: The rubbed part is not peeled off.
Δ: The rubbed part is slightly peeled off.
× ··· The rubbed part is peeled off.
[0026]
<Oxygen permeability [cc / m ² · 24h · atm]>
Using an OX-TRAN 2/20 type oxygen permeability measuring device manufactured by Modern Control Co., Ltd. using a laminate film, under conditions of a temperature of 25 ° C. and a relative humidity of 80%, and a temperature of 25 ° C. and a relative humidity of 90% It was measured.
<Water vapor permeability (moisture permeability) [g / m ² · 24h]>
A bag with a surface area of about 100 cm ² was made with the heat seal layer of the laminate film as the inner surface, and after putting an appropriate amount of calcium chloride, it was sealed. This was left in an atmosphere of 40 ° C. and 90% RH for 7 days, and the water vapor permeability was determined from the weight increase.
<Lamination strength [g / 15mm]>
Using a strip-shaped test piece having a width of 15 mm and a length of 10 cm cut out from the laminate film, Shimadzu Autograph AG-I type was used, and the 180 ° peel strength at a load cell of 5 kg and a test speed of 300 mm / min was obtained.
[0027]
Example 1 and Comparative Example 1
Using “NOVATEC PP FL6CK” (MFR 2.4, melting point 161 ° C.) manufactured by Nippon Polychem Co., Ltd. as a polypropylene resin, it is melted at an extruder temperature of 220 ° C. and extruded into a sheet form from a T die, which is cast at 30 ° C. An unstretched sheet was obtained by closely contacting the roll. Next, using a longitudinal stretching machine composed of a group of heating rolls having different peripheral speeds, this unstretched sheet is stretched in multiple stages so as to be finally 5 times at a temperature of 130 ° C., and then the surface side to be coated is 90 w · min. Corona discharge treatment was performed under the conditions of / m ² . Next, a water-soluble resin coating solution (solid content concentration of about 2.5 wt%) adjusted so that the weight ratio of the solid content becomes Example 1 and Comparative Example 1 in Table 1 was measured using a metalling bar coater. The film was coated to a thickness of about 15 μm, subsequently introduced into a tenter oven at 150 ° C., stretched 10 times in the transverse direction, and heat-set at 158 ° C. to obtain a coating film having a thickness of 20 μm. The thickness of each coating layer was about 0.04 μm.
[0028]
A high vacuum of 1 × 10 ⁻⁵ Torr was applied to the water-soluble resin-coated surface of each of the above films, and oxygen was introduced to create a vacuum of 4 × 10 ⁻⁵ Torr. The purity was 99.9% by electron beam heating. The silicon monoxide (SiO) was evaporated by heating to obtain a vapor-deposited laminated stretched film. The obtained film was left as it was, and the thickness, total light transmittance, haze, and yellowness of the deposited film were measured to evaluate the solvent resistance. Next, after forming a laminate film, oxygen permeability, water vapor permeability, and laminate strength were measured. The results are shown in Example 1 and Comparative Example 1 in Table-2. In the composition of Comparative Example 1, the fundamental oxygen barrier performance is not sufficient.
[0029]
Example 2 and Comparative Example 2
In Example 1, the solid content weight ratio of the water-soluble resin coating solution was changed to the composition shown in Example 2 and Comparative Example 2 of Table 1, and 8 × 10 ⁻⁵ Torr on the water-soluble resin coating surface. Vapor deposition of the deposited film was carried out in the same manner as in Example 1 except that oxygen was introduced and the vacuum was set to 3 × 10 ⁻⁴ Torr and the aluminum metal with a purity of 99.99% was heated and evaporated. A film was obtained. The measurement results of each physical property are shown in Example 2 and Comparative Example 2 in Table-2. In the composition of Comparative Example 2, the oxygen barrier performance on the high humidity side (25 ° C. × 90% RH) is not preferable.
[0030]
Example 3 and Comparative Example 3
As a polypropylene resin, “NOVATEC PP FL6CK” (MFR 2.4, melting point 161 ° C.) manufactured by Nippon Polychem Co., Ltd. and maleic anhydride grafted polypropylene (MFR 2.3; maleic anhydride graft ratio 0.05 wt%; melting point 138 ° C.) These were melted at 220 ° C. in separate extruders, layered in a feed block, and extruded from a T-die to produce an unstretched sheet (the maleic anhydride grafted polypropylene layer had a total thickness of 13 %), And the solid content weight ratio of the water-soluble resin coating solution was changed to the compositions shown in Example 3 and Comparative Example 3 in Table 1 in the same manner as in Example 1 except that the deposited film was laminated. A stretched film was obtained. The measurement results of each physical property are shown in Example 3 and Comparative Example 3 in Table 2. In the composition of Comparative Example 3, the solvent resistance is not preferred.
[0031]
Example 4 and Comparative Example 4
In Example 2, the weight ratio of the solid content of the water-soluble resin coating liquid was changed to the composition shown in Example 4 and Comparative Example 4 in Table 1, and the solid content concentration of the coating liquid was about 5 wt% ( A vapor-deposited laminated stretched film was obtained in the same manner as in Example 2 except that the thickness of each coating layer was about 0.08 μm. The measurement results of each physical property are shown in Example 4 and Comparative Example 4 in Table-2. In the composition of Comparative Example 4, the oxygen barrier properties, solvent resistance, and laminate strength are not sufficient.
[0032]
Comparative Example 5
In Example 1, the vapor deposition film lamination | stacking stretched film was obtained like Example 1 except the point which does not coat a water-soluble resin coating liquid. The measurement results of each physical property are shown in Comparative Example 5 in Table-2. In this configuration, oxygen barrier properties, solvent resistance, and laminate strength are not preferable.
Comparative Example 6
In Example 1, the coating film before vapor deposition was used as a sample. The measurement results of each physical property are shown in Comparative Example 6 of Table-2. In this configuration, the oxygen barrier property is not particularly preferable.
[0033]
[Table 1]

[0034]
The coating resins (a), (b) and (c) in Table 1 are as follows.
<Water-soluble acrylic resin (a)>
Acrylic 1: “Jurimer FC-80” manufactured by Nippon Pure Chemicals Co., Ltd.
<Water-soluble urethane resin (b)>
Urethane 1: “NeoRez R-9603” manufactured by Zeneca Co., Ltd. (calculated based on a solid content concentration of 34%)
Urethane 2: “Hydran AP-30” manufactured by Dainippon Ink & Chemicals, Inc. (calculated as a solid content of 20%)
<Polyvinyl alcohol (c)>
PVA1: “GOHSENOL N-300 (degree of polymerization 1650 to 1700 saponification degree 98 to 99 mol%)” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.
PVA2: “GOHSENOL GM-14 (degree of polymerization 1650 to 1700 saponification degree 86.5 to 89 mol%)” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.
For the method of dissolving PVA1 and PVA2 (granular) in water, refer to the catalog of the product, and add (a) and (b) to the aqueous solution in which (c) is dissolved to add a water-soluble resin coating solution. Adjusted.
[0035]
[Table 2]

[0036]
【The invention's effect】
A gas barrier film obtained by the present invention, that is, a polypropylene resin molded article on which an inorganic oxide thin film is deposited, has excellent gas barrier properties not only on the low humidity side but also on the high humidity side. Since the metal oxide thin film does not peel off during use and the gas barrier property is not lowered, and it has excellent transparency and solvent resistance, food, industrial goods, pharmaceuticals, etc. can be used as an inexpensive packaging material to replace PVDC-coated OPP. It can be widely used as a resin molded product for packaging that is used to protect the film.

Claims (2)

An unstretched film obtained by melt extrusion of a polypropylene resin is stretched in the machine direction and subjected to corona discharge treatment. Next, a water-soluble acrylic resin (a), a water-soluble urethane resin ( b) and polyvinyl alcohol (c), and a water-soluble resin coating solution having a weight ratio in solid content satisfying the following formulas (1) to (3) is applied and stretched in the transverse direction, and then on the coating surface A method for producing a gas barrier film, comprising forming a vapor-deposited film of an inorganic oxide on the substrate.
[Formula 1]

A method for producing a gas barrier laminate film, comprising a heat seal layer provided on the gas barrier film of claim 1.