JP3641981B2 - Gas barrier film - Google Patents

Description

【００３０】
評価
実施例１〜３及び比較例１〜３で得られた各ガスバリアフィルムを４０℃、９０ＲＨ％の雰囲気化に１ヶ月保存し、保存前後の（１）酸素透過度、（２）水蒸気透過度を次のように測定した。
【００３１】
酸素透過度
酸素透過度測定装置（モダンコントロール社製、ＯＸＴＲＡＮ １０／４０Ａ）を用いて、３０℃・７０ＲＨ％および３０℃・１００ＲＨ％雰囲気下で測定した。
【００３２】
水蒸気透過度
水蒸気透過度測定装置（モダンコントロール社製、ＰＥＲＭＡＴＲＡＮ Ｗ６）を用いて、４０℃・９０ＲＨ％雰囲気下および４０℃・１００ＲＨ％雰囲気下で測定した。
結果を表１に示す。これから分かるように、ポリビニルアルコールと層状化合物を一定の比率で混合した場合、硼酸を添加しない系よりも、硼酸を添加した系の方がガスバリア性が良好である。
【００３３】
実施例４〜６
表２のような配合比でテトラエトキシシラン加水分解物を添加したこと以外は実施例１〜３と同様にガスバリアフィルムを作成した。
【００３４】
比較例４〜６
表２に示すように、硼酸を添加しないこと以外は実施例４〜６を繰り返すことによりガスバリアフィルムを作成した。
【００３５】
【表２】

【００３６】
表２から分かるように、硼酸を添加した実施例は、硼酸を用いない比較例よりもバリア性が高い。
【００３７】
このように、張力をかけた後でも、従来のガスバリアフィルムよりも高いガスバリア性を維持し、加工適性に優れると言える。
【００３８】
【発明の効果】
本発明によれば、酸素透過度、水蒸気透過度が低く、湿度劣化が抑制され、保存適性に優れたガスバリアフィルムを得ることが可能である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas barrier film. More specifically, the present invention relates to a gas barrier film suitable as a packaging film that suppresses deterioration, deterioration, or the like of foods, pharmaceuticals, electronic members, electronic devices, optical members, and the like due to oxygen, water vapor, and the like.
[0002]
[Prior art]
Various functions are required for the packaging material. The alteration and deterioration of the contents are promoted mainly by the influence of oxygen, moisture, light, heat and the like. In particular, the influence of oxygen and moisture is great, and it is important to consider blocking the contents, that is, the presence of a high-performance gas barrier film is required.
[0003]
In addition, in today's diverse preferences and various additives are subject to legal regulations, not only external blocking, but also inert gas-filled packaging, and prevention of flavor and aroma degeneration For example, it is necessary to block transmission from the inside to the outside.
[0004]
However, plastic films are generally poor in gas barrier properties alone, and some plastic films that retain gas barrier properties even under high humidity are not excluded. In addition, some examples include chlorinated polymers such as polyvinylidene chloride, which are suspected of generating harmful dioxins during incineration and are not necessarily optimal. .
[0005]
Therefore, a method of producing a gas barrier film by laminating other layers having excellent gas barrier properties is employed.
[0006]
A film having a layer containing polyvinyl alcohol as a component is known to have excellent crystallinity and excellent oxygen barrier properties in a dry state. The problem is that it drops significantly.
[0007]
Various methods have been devised to improve the problem. As a non-hydroxyl group, a gas barrier film provided with a polyvinylidene chloride layer has been put into practical use, but has the disadvantage of generating harmful dioxins during disposal as described above. Moreover, in order to improve the water resistance of polyvinyl alcohol, the result of poly (vinyl alcohol-co-ethylene) in which an ethylene unit is introduced into polyvinyl alcohol is also known.
[0008]
In recent years, methods for producing a composite film of polyvinyl alcohol and a layered compound have been considered (Japanese Patent Laid-Open Nos. 7-41685, 7-33909, 7-251475, etc.), and the effects thereof are also known. Its resistance to humidity is still not sufficient.
[0009]
[Problems to be solved by the invention]
The conventional gas barrier film containing polyvinyl alcohol as a component has a drawback that the barrier property is remarkably lowered in a high humidity state.
[0010]
The object of the present invention is to maintain a higher barrier property than conventional gas barrier films even under high humidity conditions.
[0011]
[Means for Solving the Problems]
As a result of diligent studies to solve the above problems, the present invention provides a gas barrier film in which a composite coating layer formed of a mixture mainly composed of polyvinyl alcohol, an inorganic layered compound and boric acid is provided on at least one side of a substrate. It is an invention that has been found to be created.
[0012]
Moreover, the gas barrier film whose inorganic layered compound in a composite film is a montmorillonite is provided.
[0013]
Further, the ratio of polyvinyl alcohol (A), inorganic layered compound (B) and boric acid (C) in the composite coating layer is (A) / (B) = 10/90 to 99/1 and (C) / {( A) + (B) + (C)} = 1/1000 to 1/2 A gas barrier film is provided.
[0014]
In addition, the present invention provides a gas barrier film characterized in that the substrate is a plastic film or a ceramic deposited film provided with a ceramic deposited layer thereon.
[0015]
As a more preferred embodiment, there is provided a gas barrier film in which the ceramic is silicon oxide, aluminum oxide or titanium oxide.
[0016]
The present invention also provides a gas barrier film characterized in that a hydrolyzate of a metal alkoxide is further contained in the composite coating layer.
[0017]
Furthermore, as a preferred embodiment thereof, a gas barrier film is provided in which the metal forming the metal alkoxide is silicon, aluminum, or titanium.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The layered compound in the present invention refers to a crystalline inorganic compound having a layered structure. The particle size, aspect ratio, type, and the like can be appropriately selected according to the purpose of use of the gas barrier film, and include chalcogenite, pnictide, transition metal oxides and halides, swelling properties, complex formation, etc. As a high chemical activity, clay minerals such as smectite, hectorite, saponite, mica, montmorillonite, or zinc phosphate, cobalt phosphate, vanadium oxide salt, aluminum phosphate, vanadium phosphate, oxovanadium phosphate, Metal salts such as zinc bisphosphonate are preferred.
[0019]
Montmorillonite is particularly preferred. However, it is not limited to the above example.
[0020]
In the present invention, the ratio between the polyvinyl alcohol (A) and the layered compound (B) is (A) / (B) = 10/90 to 99/1. If it is lower than 10/90, the stability of the formed film is lowered, and if it is higher than 99/1, the action of the layered compound on polyvinyl alcohol is not sufficient, and the barrier property is not excellent at high humidity.
[0021]
The amount of boric acid (C) added is (C) / {(A) + (B) + (C)} = 1/1000 to 1/2. More preferably, it is 1/20 to 1/4, but is not limited thereto. When the ratio is larger than 1/2, the liquid becomes unstable. Conversely, when the ratio is smaller than 1/1000, the effect is hardly exhibited.
[0022]
The base material to which this liquid mixture is applied is not particularly limited, and a known film such as polyolefin, nylon, or polyester may be appropriately used depending on the application. Moreover, when using a ceramic vapor deposition film for a base material, although the kind of ceramic is not specifically limited, a silicon oxide type, an aluminum oxide type, a titanium oxide type etc. are suitable in view of ease of handling and economy.
[0023]
Examples of the deposition method include a vacuum deposition method, a sputtering method, a plasma vapor deposition method (CVD method), and the like, but are not limited thereto. As a coating method, a known coating method such as a dipping method, a roll coating method, a screen printing method, or a spray method can be used. This is then dried. Thereby, a composite film layer can be formed on a base material.
[0024]
Here, when the composite coating layer is formed on one side of the substrate, it is preferable to coat the composite coating layer so that the thickness of the composite coating layer after drying is about 0.01 to 100 μm. It is preferable to set the thickness to 01 to 50 μm. If it is thinner than this, it is difficult to form a coating film, and even if it is formed, it is unstable. Conversely, if it is too thick, it is uneconomical.
[0025]
【Example】
Polyvinyl alcohol (A), montmorillonite (B), and boric acid (C) (A) / (B) = 10/90 to 99/1, (C) / {(A) + (B) + (C)} = The container was charged at a ratio of 1/1000 to 1/2. Subsequently, water was added so that the total solid content was 3.5%.
[0026]
Moreover, according to a use, solvents, such as alcohol, a metal alkoxide hydrolyzate, etc. were added. In mixing, stirring was performed while heating to 100 ° C. or lower.
[0027]
Examples 1-3
A biaxially stretched polypropylene film having a thickness of 20 μm provided with a urethane-based undercoat layer was used as a base material. Further, a coating agent was prepared from montmorillonite, polyvinyl alcohol, and boric acid so as to have the composition shown in Table 1. The coating agent was applied onto a substrate using a gravure coater and dried by passing through an oven at 100 ° C. to form a composite coating layer having a dry film thickness of 0.3 μm to obtain a gas barrier film.
[0028]
Comparative Examples 1-3
As shown in Table 1, gas barrier films were prepared by repeating Examples 1 to 3 except that boric acid was not used.
[0029]
[Table 1]

[0030]
Each gas barrier film obtained in Evaluation Examples 1 to 3 and Comparative Examples 1 to 3 was stored in an atmosphere of 40 ° C. and 90 RH% for 1 month, and (1) oxygen permeability and (2) water vapor permeability before and after storage. Was measured as follows.
[0031]
Oxygen permeability The oxygen permeability was measured in an atmosphere of 30 ° C./70 RH% and 30 ° C./100 RH% using an oxygen permeability measuring device (manufactured by Modern Control, OXTRAN 10 / 40A).
[0032]
Water vapor permeability The water vapor permeability was measured in a 40 ° C./90 RH% atmosphere and a 40 ° C./100 RH% atmosphere using a water vapor permeability measuring apparatus (PERMATRAN W6, manufactured by Modern Control).
The results are shown in Table 1. As can be seen from this, when polyvinyl alcohol and the layered compound are mixed at a certain ratio, the gas barrier property is better in the system in which boric acid is added than in the system in which boric acid is not added.
[0033]
Examples 4-6
A gas barrier film was prepared in the same manner as in Examples 1 to 3 except that the tetraethoxysilane hydrolyzate was added at a blending ratio as shown in Table 2.
[0034]
Comparative Examples 4-6
As shown in Table 2, gas barrier films were prepared by repeating Examples 4 to 6 except that boric acid was not added.
[0035]
[Table 2]

[0036]
As can be seen from Table 2, the examples with boric acid added have higher barrier properties than the comparative examples without boric acid.
[0037]
Thus, even after tension is applied, it can be said that the gas barrier property higher than that of the conventional gas barrier film is maintained and the processability is excellent.
[0038]
【The invention's effect】
According to the present invention, it is possible to obtain a gas barrier film having low oxygen permeability and water vapor permeability, suppressed humidity deterioration, and excellent storage stability.

Claims (7)

A gas barrier film in which a composite coating layer formed of a mixture mainly composed of polyvinyl alcohol, an inorganic stratiform compound and boric acid is provided on at least one surface of a substrate. The gas barrier film according to claim 1, wherein the inorganic layered compound is montmorillonite. The weight ratio of polyvinyl alcohol (A), inorganic layered compound (B) and boric acid (C) in the composite coating layer is (A) / (B) = 10/90 to 99/1, and (C) / {( The gas barrier film according to claim 1, wherein A) + (B) + (C)} = 1/1000 to 1/2. The gas barrier film according to any one of claims 1 to 3, wherein the substrate is a plastic film or a ceramic vapor-deposited film provided with a ceramic vapor-deposited layer thereon. The gas barrier film according to claim 4, wherein the ceramic is silicon oxide, aluminum oxide, or titanium oxide. The gas barrier film according to any one of claims 1 to 5, wherein a hydrolyzate of a metal alkoxide is further contained in the composite coating layer. The gas barrier film according to claim 6, wherein the metal forming the metal alkoxide is silicon, aluminum, or titanium.