JPS62148532A - Gas-barriering transparent plastic film and its production - Google Patents

Abstract

PURPOSE:To obtain the titled film by coating a releasable base with a coating liquid of specific viscosity made up of a solvent and a resin composition prepared by incorporating a transparent thermoplastic resin with flaky mica fine powder, and drying followed by peeling off the base. CONSTITUTION:A coating liquid composition with a viscosity at 30 deg.C <=2,000 poises comprising a solvent and a resin composition prepared by incorporating 100pts.wt. of a transparent thermoplastic resin with 50-300pts.wt. of flaky mica fine powder is coated on a releasable base and dried. Thence, the resultant resin composition just dried is peeled off the base, thus obtaining the objective film with an average diameter along the flat surface of the mica flakes <=500mu, aspect ratio >=5 and said flat surface arranged almost parallel to the film surface, having such fine structure that the mica flakes are laminated in many tiers in the direction of film thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transparent glass film with excellent gas barrier properties and a method for grading the same. More specifically, the present invention relates to a plastic film that improves gas barrier and vapor barrier properties while maintaining transparency by filling a thermoplastic resin with mica, and a method for manufacturing the same using a solution casting method.

[Prior art]

Plastics have the advantage of being more flexible than metals, glass, ceramics, etc., but plastics generally consist of only amorphous parts or have a structure in which crystalline parts and non-crystalline parts coexist; The mobility of the polymer in the part is high, which makes it easy to diffuse various low-molecular substances,
Compared to metals, glass, ceramics, etc., it has the property of being more permeable to gases, water vapor, etc.

In order to improve the gas barrier properties of plastics, in the field of packaging materials, innovations such as laminating aluminum foil with high gas barrier properties to glass film are being carried out.

However, since aluminum foil blocks light, aluminum laminate cannot be used in applications that require transparency.

Glass is commonly used as a gas barrier material in applications that require transparency, but glass has the essential drawback of being easily broken when handled, and cannot be used in applications that require flexibility.

Among plastics, there are materials such as polyvinyl alcohol and polyvinylidene chloride that have excellent gas barrier properties, but their gas barrier properties are insufficient compared to aluminum foil and the like. Plastics with excellent water vapor barrier properties include polyethylene, polyvinylidene fluoride, polytetrafluoroethylene, and polychlorotrifluoroethylene, but their water vapor barrier properties are insufficient compared to aluminum foil and the like.

Recently, 8i0. Vapor deposition or coating of inorganic materials such as nitrates, etc. have been proposed, but these methods require extra processing steps and are therefore economically disadvantageous.

[Purpose of the invention]

The present invention was developed as a result of research into a method for improving the gas barrier and water vapor barrier properties of plastic films while maintaining transparency. By dispersing transparent flaky mica within the plastic film, gas permeability is reduced. I got the knowledge that.

Furthermore, based on this knowledge, various researches were carried out and the present invention was completed.

The purpose of the present invention is to maintain transparency while
To provide a plastic film with improved gas barrier properties and water vapor barrier properties, and a method for producing the same.

[Structure of the invention]

The gas barrier transparent plastic film of the present invention is a transparent plastic film whose main component is a resin composition in which 50 to 300 parts by weight of flaky mica fine powder is added to 100 parts by weight of a transparent thermoplastic resin. , the average diameter of the mica flakes along the flat surface is 5001nr1 or less, and the aspect ratio is 5 or more, and the flat surface of the mica flakes is relative to the film surface. The mica is arranged almost in parallel, and is characterized by having a fine structure in which the mica is laminated in multiple layers in the thickness direction of the film.

In the present invention, transparent thermoplastic resins include sterol resins, polyurethane resins, silicone resins, vinyl chloride resins, polycarbonate resins, vinylidene chloride resins, polyvinyl alcohol resins, ethylene-vinyl alcohol copolymer resins, and fluorocarbon resins. Vinylidene chloride resin, polychlorotrifluoroethylene resin, tetrafluoroethylene copolymer resin, polyethylene resin, polypropylene resin, polysulfone resin, polyethersulfone resin, etc., and are soluble in solvents, although not limited to C2. A resin is preferable.

50 to 300 parts by weight of flaky mica fine powder is added to 100 parts by weight of the thermoplastic resin. If the added acid of the mica is less than 50 parts by weight per 14 parts by weight of the resin, the gas and water vapor shielding effect due to mica filling becomes weak, and the difference from the case where mica is not filled becomes extremely small. If the mica addition difference is 300 parts or more relative to the resin 100 parts, the film becomes brittle and the transparency decreases.

The average diameter of the mica flakes along the flat surface is 500μ
m or less, and the aspect ratio is 5 or more.

If the average diameter is 500 μm or more, it is difficult to obtain a transparent film with good appearance.

The aspect ratio, which is the ratio of the average radius of curvature along the flat surface of the mica flake to the thickness, is 5 or more, particularly 10 to 5.
Mica fine powder having an aspect ratio varying by about 0 is preferred. If the aspect ratio is 5 or less, it becomes difficult for mica to be arranged along the film surface, and even if mica is arranged, the gas and water vapor shielding effect will be reduced.

In the film of the present invention, the flat surfaces of the mica flakes are arranged almost parallel to the surface of the film, and the film has a fine structure in which the mica is laminated in multiple layers in the thickness direction of the film. When the flat surfaces of the mica flakes are arranged parallel to the film surface and the mica is stacked in multiple layers in the thickness direction of the film, allowing gas, moisture, etc. to permeate through the film, mica It is thought that the layer acts as an effective barrier and improves gas barrier properties. When gas, moisture, etc. diffuse inside the film, the interior of the mica is almost impervious to gas, moisture, etc., so the diffusing gas molecules pass through the Jugetsuji layer in the gaps between the mica. I'm going to go. When mica is arranged parallel to the film surface and stacked, the path for the gas molecules to diffuse becomes longer than when mica is not present or when mica is arranged in a random arrangement, and therefore the gas barrier It is estimated that the performance will improve. The gas barrier properties improve as the bond Δ number of mica increases in the film thickness direction, but transparency decreases as the number of laminated layers increases.

The method for producing a gas barrier transparent plastic film of the present invention comprises a resin composition in which 50 to 300 parts by weight of flaky mica fine powder is added to 100 parts by weight of a transparent thermoplastic resin, and a solvent. This is a method in which a coating liquid composition is deposited on a releasable base layer and dried, and then the dried resin composition is peeled off from the releasable base layer. The viscosity at 30℃ is 2
,000 poise or less. In the coating liquid composition, the resin composition may be dissolved in a solvent, or may be dispersed in the form of an emulsion or suspension. It is coated and dried.The releasable base material is not particularly limited, and may be paper laminated with a film of polypropylene, polyester, etc., stainless steel, glass film, etc.The releasable base material is the same as the formed film. Appropriate mold releasability is required.If the formed and dried film easily peels off from the releasable base material, the film will float and detach from the releasable base material surface during the film forming process. Trouble may occur during the manufacturing process.If the formed film adheres too strongly to the releasable substrate, the film may be removed from the substrate surface during the process of peeling the formed film from the releasable substrate surface. There is a risk that it will tear without peeling.

The viscosity of the coating liquid composition at 30°C is 2,000 poise or less. When the coating liquid composition is applied to the mold release base Murakami and dried, the viscosity of the coating liquid is too high.

The fluidity of the coating liquid on the releasable base material deteriorates, and the arrangement of mica deteriorates.

The thickness of the film of the present invention is not particularly limited, but is 10 μm.
The thickness is preferably in the range of 500 μm to 500 μm. Thickness is lOtm=
Under IU, gas barrier properties decreased and the thickness decreased to 500 μm.
Above that, the transparency becomes low F.

〔Effect of the invention〕

The plastic film of the present invention is transparent and has excellent gas barrier properties and water vapor barrier properties. The gas and water vapor barrier properties of the film of the present invention are improved by about 2 to 5 times as compared to a film formed from only the resin material. When the resin material has high gas barrier properties and water vapor barrier properties, the film of the present invention is even more effective because it can improve the gas barrier properties and water vapor barrier properties while taking advantage of the inherent properties of the resin, such as transparency.

〔Example〕

1-6-hexane polycarbonate diol with a concentration of 30% polyurethane dendritic solution (Luxkin 83-3 manufactured by Seiko Kasei Co., Ltd.) For 100 heavy Kawabe = 25 parts by weight of fine mica powder, 60 parts by weight of dimethylformamide
@ part was added to prepare a coating solution. This φ2 liquid was applied to the upper surface of a release paper placed horizontally to the floor surface, dried to simulate a tear, and then peeled off to obtain a film with a thickness of 75 μm.

For comparison, a solution containing only the resin was prepared by removing the mica fine powder from the above two liquids, and a film with a thickness of 75 μm was prepared in the same manner.

Oxygen gas barrier properties and water vapor permeability (1 constant) were measured for the polyurethane film without mica added in the comparative example and the polyurethane film added with finely powdered mica in the example. The measured value of moisture permeability and the constant value of oxygen permeability (d11) are shown.

Table 1 The film of the present invention has improved water vapor barrier property by 3.4 times and oxygen gas barrier property by 475 times compared to the film of the comparative example. The film of the present invention has a light transmittance of 20%
As described above, the contact visibility is high, and characters, images, etc. can be clearly seen through the film.

Claims (3)

[Claims] (1) A transparent plastic film whose main component is a resin composition in which 50 to 300 parts by weight of flaky mica fine powder is added to 100 parts by weight of a transparent thermoplastic resin, and the mica The average diameter along the flat surface of the flakes is 500 μm or less, and the aspect ratio is 5.
The above gas barrier has a fine structure in which the flat surfaces of the mica flakes are arranged almost parallel to the film surface, and the mica is laminated in multiple layers in the thickness direction of the film. transparent plastic film. (2) Consisting of a resin composition containing 50 to 300 parts by weight of flaky mica fine powder to 100 parts by weight of a transparent thermoplastic resin and a solvent, the viscosity at 30°C is 2,000 poise or less. A gas barrier transparent plastic film characterized in that a coating liquid composition is applied onto a releasable base material, dried, and then the dried resin composition is peeled off from the releasable base material. Production method. (3) Production of a gas barrier transparent plastic film according to claim (2), wherein the fine mica powder has an average diameter of 500 μm or less along the flat surface of its flakes and an aspect ratio of 5 or more. Method.