JPH10235778A - Laminated film of high barrier property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a laminated film provided with superior moistureproofness, gas barrier properties and transparency and also provided with the static preventing effect, which is used suitably for packaging foods, pharmaceuticals and the like. SOLUTION: At least one face of a transparent base film of polyester or the like is coated with a barrier resin layer containing a vinyl vinilidene chloride copolymer and the like through an inorganic vapor-deposited layer of transparent aluminum oxide or silicon oxide, and a static preventing layer is formed on the barrier resin layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-barrier laminated film, and more particularly, it has transparency, excellent moisture-proof properties and gas-barrier properties, and has an antistatic effect required as a packaging film for foods, pharmaceuticals and the like. To a laminated film.

[0002]

2. Description of the Related Art Conventionally, packaging films used for packaging foods, pharmaceuticals, etc., require high transparency in view of the visibility and aesthetics of the contents, and prevent moisture absorption and oxidation of the contents. Therefore, moisture-proof properties and gas barrier properties are required. In addition, static electricity often becomes an obstacle at the time of film processing or after packaging of contents, and thus, measures against static electricity of the film are required.

[0003] As a transparent gas barrier film, a plastic film such as biaxially oriented polyester or biaxially oriented polypropylene is coated or laminated with a resin having excellent gas barrier properties such as vinylidene chloride or ethylene-vinyl alcohol copolymer on the surface thereof. Films are known. However, the film on which the gas barrier polymer is laminated has insufficient gas barrier properties against water vapor, oxygen and the like, and the gas barrier particularly at high temperatures is significantly reduced.

A film in which an inorganic thin film is formed on a base film includes, for example, silicon oxide (JP-A-49-41469).
No. JP-A-62-10) or aluminum oxide
No. 1428) is known. However, such a transparent inorganic vapor-deposited film easily generates scratches and pinholes due to friction and bending, and deteriorates gas barrier properties. In addition, a film on which silicon oxide or aluminum oxide is deposited has insufficient measures for preventing static electricity and is easily charged.

Providing a transparent resin layer on the transparent inorganic vapor-deposited layer has effects such as protection of the vapor-deposited film from external stress, moisture-proof property and gas barrier property. US Patent No. 34426
No. 86, Japanese Utility Model Publication No. 57-34034, and Japanese Patent Application Laid-Open No. 7-80986 are disclosed by coating a plastic film having a transparent inorganic vapor-deposited layer with a resin such as vinylidene chloride on the transparent inorganic vapor-deposited surface. In addition, there is a description in which protection of a deposited film, gas barrier properties, heat sealing properties, and the like are provided.

[0006] On the other hand, plastic films and laminates thereof are used in various fields, but have the drawback that the film is charged by contact or peeling due to the dielectric properties of the plastic itself. When the plastic film or its laminate is charged, dust and dirt adhere to it, which is not preferable as a packaging material for foods, medicines and the like. In addition, when performing processing such as printing on a plastic film, there is a problem that the suitability for paper feeding and paper discharging deteriorates. Conventionally, as a method for preventing static charge of a plastic film or a laminate thereof, a charge neutralization method using ionized air, a method of mixing an antistatic agent with a resin or applying the film to a film are known. However, the charge neutralization method requires a device for this purpose, and has disadvantages such as poor sustainability of the effect. Also, the method of mixing the antistatic agent with the resin or applying it to the film,
There is a problem that the antistatic performance is not stable, or the antistatic agent falls off during printing, lamination, or bag making, and the antistatic performance is reduced.

[0007] JP-A-7-252456 discloses an adhesive primer comprising a crosslinkable polymer, wherein the outer surface of the film is the base film itself and which can maintain high antistatic performance, and the primer. A laminated film having layers is described. This can improve the drawbacks caused by the charge neutralization method using ionized air and the method of mixing or applying an antistatic agent to the film resin, but cannot improve the moisture resistance and gas barrier properties.

As described above, the transparent inorganic vapor-deposited plastic film has a high moisture-proof property and a gas barrier property. In addition to the transparency, it is possible to control the decrease in the moisture-proof property and the gas barrier property due to mechanical external force accompanying processing and use. It is still insufficient to provide an antistatic effect and printability.

[0009]

OBJECTS OF THE INVENTION Accordingly, an object of the present invention is to provide a high barrier laminated film having excellent moisture proofing properties, gas barrier properties and transparency, and having an antistatic effect.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention has been studied as a result, and as a result, an inorganic vapor-deposited layer formed on the surface of a substrate film layer is coated with a barrier resin, and an antistatic effect is further formed thereon. By laminating a resin with a layer, a moisture-proof property and a gas barrier property are further improved than a laminated film in which only a barrier resin layer is provided on a transparent inorganic vapor-deposited plastic film, and a film having transparency and an antistatic effect can be obtained. Was found.

According to the present invention, at least one side of the base film (a) is coated with a barrier resin layer (c) via an inorganic vapor-deposited layer (b) having transparency,
The laminated film further includes an antistatic layer (d) provided on the barrier resin layer (c).

The base film (a) is a transparent sheet-like or film-like material, such as polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamide (Nylon-6, nylon-66, etc.), polyvinyl chloride, polyimide, etc., or a copolymer thereof,
Unstretched or stretched films can be used. The substrate is appropriately selected from the above materials depending on the application, but a biaxially stretched polyethylene terephthalate film is preferable from the viewpoint of deposition suitability.

The base film can be formed by a conventional film forming method, for example, a melt forming method such as a T-die method or an inflation method, or a casting method using a solution. The base film may be unstretched or uniaxially or biaxially stretched. As the stretching method, a conventional stretching method, for example, tenter stretching, tube stretching, roll stretching, rolling stretching, belt stretching, or a combination thereof can be applied.

The thickness of the substrate film is not particularly limited and is appropriately selected in consideration of packaging suitability, mechanical strength, flexibility and the like, but is usually 3 μm to 200 μm, preferably 5 μm to
It is about 100 μm.

Known additives such as an antistatic agent, an ultraviolet absorber, a plasticizer, a lubricant, and a coloring agent are appropriately added to the resin material used for the base film (a) as necessary.

Further, at least one surface of the base film (a) may be surface-treated or anchor-coated.
Examples of the surface treatment include corona discharge treatment, plasma treatment, glow discharge treatment, reverse sputtering treatment, flame treatment, chromic acid treatment, solvent treatment, and surface roughening treatment. The anchor coat agent can be composed of various resins, for example, a thermoplastic resin, a thermosetting resin, a light-curable resin, and a coupling agent. By these surface modifications, the inorganic vapor deposition layer (d)
It is possible to improve the adhesion of the film.

The inorganic vapor-deposited layer (b) is composed of silicon, aluminum, titanium, zirconium, tin, magnesium, or an oxide, nitride, or fluoride alone, or a composite thereof, and is formed by a vacuum deposition method or a sputtering method. ,
It is formed by a vacuum process such as a plasma vapor deposition method (CVD method). In particular, aluminum oxide and silicon oxide are colorless and transparent, have excellent properties such as boiling and retort resistance, and can be used in a wide range of applications.

The thickness of the inorganic vapor-deposited layer (b) varies depending on the application, and is generally in the range of several tens to 5,000 angstroms. However, in view of the continuity of the thin film, the possibility of occurrence of cracks, and the flexibility. , Preferably 50 to 3000 angstroms.

The barrier resin layer (c) is generally made of a resin having a high gas barrier property, for example, a vinylidene chloride-based copolymer, an ethylene-vinyl alcohol-based copolymer, a polyamide-based polymer, a polyvinyl alcohol-based polymer, Although it is composed of an acrylonitrile-based polymer, a urethane-based polymer, or the like, a preferred barrier resin is a vinylidene chloride-based copolymer.

The thickness of the barrier resin layer (c) is appropriately selected within a range that does not impair the properties of the film, but is preferably about 0.2 μm to 4.0 μm.

In the case of the vinylidene chloride copolymer used for the barrier resin layer (c), it is preferably applied to the inorganic vapor-deposited layer in the form of a solution or a dispersion.

The function of the antistatic layer (d) is based on a function completely different from that of the conventional antistatic agent, which dissipates the charge due to the low surface resistivity of the antistatic agent, and is based on the function of preventing static induction (dielectric). . Such a film having an effect of preventing electrostatic induction is provided on a film substrate, and a composite film adhered to another film substrate is formed on the outer surface of the film so that the layer having the effect of preventing electrostatic induction is located inside. Despite the high surface resistivity of the material film, it is possible to obtain a composite film that does not generate friction or peeling charge. Therefore, the antistatic layer (d) is composed of a material having an effect of preventing electrostatic induction, for example, a resin containing conductive inorganic particles, a conductive inorganic thin film, an olefin-based ionomer, an acrylic-based ionomer, and the like. An acrylic ionomer having an effect of preventing electrostatic induction is preferred from the viewpoint of transparency and adhesiveness. More preferably,
It is desirable that the acrylic ionomer is an adhesive primer that is a crosslinkable copolymer having at least a carboxyl group and a quaternary ammonium base in the side chain. For example, an adhesive primer which is a crosslinkable copolymer of an acrylic ionomer uses a water / isopropanol mixed solution containing 30 to 40% by weight of an acrylic ionomer as a main component, and water / isopropanol containing 2 to 8% by weight of an epoxy resin. The mixed solution is used as a curing agent. After mixing and diluting the main agent / curing agent at 1/1 to a predetermined concentration, a coating is formed by a conventional coating method and dried to form a film. A layer having a prevention effect can be formed.

The thickness of the antistatic layer (d) is appropriately selected within a range that does not impair the properties of the film. However, from the viewpoint of obtaining a sufficient antistatic effect and being economical, the thickness is preferably 0.05 μm to 1 μm. It is about 0.0 μm.

The coating method is not particularly limited, and conventional methods such as a gravure coating method, a reverse coating method, a roll coating method, a bar coating method, a spray coating method, and an air knife coating method can be employed.

The thickness of the high barrier laminated film of the present invention is not particularly limited and is appropriately selected in consideration of packaging suitability, mechanical strength, flexibility, etc., and is usually 3 μm to 200 μm, preferably about 5 μm to 100 μm. is there.

Although the light transmittance of the high barrier laminated film of the present invention can be appropriately selected, the total light transmittance in white light is preferably
It is usually at least 40%, preferably at least 60%, more preferably at least 80%.

The barrier properties of the high-barrier laminated film of the present invention may be any degree necessary to prevent the contents from being deteriorated due to moisture absorption or oxidation.
01-5.0 cc / m ² / day, preferably 0.01
~2.0cc / m ² / day, more preferably 0.01
１．０1.0 cc / m ² / day. The moisture permeability is
0.01 to 5.0 g / m ² / day, preferably 0.0
1 to 2.0 g / m ² / day, more preferably 0.01
１．０1.0 g / m ² / day.

The antistatic performance of the high barrier laminated film of the present invention can be represented by the surface resistivity of the antistatic layer. It is usually 10 ¹² Ω or less, preferably 10 ¹⁰ Ω or less.

The heat seal layer can be formed by a conventional method, for example, a dry lamination method, depending on the type of the heat-adhesive polymer.
It can be formed by an extrusion lamination method, a coating method, or the like.

Further, in the laminated film of the present invention, various laminated layers may be further formed according to the type and use of the film.

[0031]

The laminated film of the present invention has a transparent inorganic vapor-deposited layer (b), a barrier resin layer (c), and an antistatic layer (d) provided on a base film layer (a). Therefore, transparency, moistureproofness and gas barrier properties are extremely high, and are not easily affected by charging.

[0032]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 Vinylidene chloride copolymer emulsion (trade name: Kurehalon latex DoAX-, manufactured by Kureha Chemical Industry Co., Ltd.)
Water was added to 2) to adjust to 15% by weight. This coating solution was coated on one side of a 12 μm-thick biaxially stretched polyethylene terephthalate film with aluminum oxide by vacuum deposition (manufactured by Toyo Metallizing Co., Ltd., trade name: BA
RRIALOX 1011HG) was applied onto the inorganic vapor-deposited surface at an application amount of 1.0 g / m ^2, and then dried in an oven at 90 ° C. for 10 seconds to obtain a laminated film. On the vinylidene chloride copolymer coated surface of this laminated film,
Antistatic coating agent made of acrylic ionomer (Konishi Co., Ltd., trade name: Bondip PA100)
Was mixed with a main agent / curing agent = 1/1 (weight ratio) and diluted with a water / isopropanol-based mixed solvent to adjust the resin concentration to 4% by weight. After each application so that the application amount becomes 0.2 g / m ² , 90
Drying in an oven at a temperature of 15 ° C. for 15 seconds gave a laminated film. Further, a composite film obtained by dry lamination with a non-stretched polypropylene film (# 25CP GHC manufactured by Tosello Co., Ltd.) was also obtained.

Example 2 The film obtained by vacuum-depositing aluminum oxide of Example 1 (manufactured by Toyo Metallizing Co., Ltd., trade name: BARRIA)
LOX 1011HG) in the same manner as in Example 1 except that silicon oxide was vacuum-deposited on one surface of a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm (GT1000N, manufactured by Toyo Ink Co., Ltd.). Thus, a laminated film of Example 2 was obtained. Furthermore, a non-stretched polypropylene film (# 25CP manufactured by Tocelo Co., Ltd.)
A composite film dry-laminated with GHC) was also obtained.

Example 3 A vinylidene chloride resin (trade name: Saran Resin F216, manufactured by Asahi Kasei Corporation) was diluted with a tetrahydrofuran / toluene-based mixed solvent to adjust the resin concentration to 10% by weight. This coating solution was applied on the evaporation surface of the aluminum oxide evaporation film used in Example 1 so as to have an application amount of 0.6 g / m ^2, and then dried in an oven at 90 ° C. for 10 seconds. Then, the coating solution of the antistatic coating agent used in Example 1 was further coated on the coated surface with a coating amount of 0.2 g /
After coating so that the m ^2, 1 at 90 ° C. in an oven
After drying for 5 seconds, a laminated film was obtained. Furthermore, a non-stretched polypropylene film (# 25CP manufactured by Tocelo Co., Ltd.)
A composite film dry-laminated with GHC) was also obtained.

Example 4 Vinylidene chloride copolymer emulsion (Kureha Chemical Industry Co., Ltd., trade name: Klehalon latex Do821)
Water was added to S) to adjust to 30% by weight. This coating solution was applied on the evaporation surface of the aluminum oxide evaporation film used in Example 1 so as to have an application amount of 1.0 g / m ^2, and then dried in an oven at 90 ° C. for 10 seconds. And
Further, on the coated surface, a coating solution of the antistatic coating agent used in Example 1 was applied so as to have a coating amount of 0.2 g / m ^2, and then dried in an oven at 90 ° C. for 15 seconds.
A laminated film was obtained. Further, a composite film obtained by dry lamination with a non-stretched polypropylene film (# 25CP GHC manufactured by Tosello Co., Ltd.) was also obtained.

Comparative Example 1 A film obtained by vacuum-depositing aluminum oxide on one surface of a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm (trade name: BARR, manufactured by Toyo Metallizing Co., Ltd.)
IALOX 1011HG) was used as is. Furthermore, a non-stretched polypropylene film (manufactured by Tocelo Corporation #
25CP GHC) and a composite film that was dry-laminated.

Comparative Example 2 A film obtained by vacuum-depositing silicon oxide on one surface of a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm (trade name: GT1000N, manufactured by Toyo Ink Co., Ltd.) was used as it was. Further, a composite film obtained by dry lamination with a non-stretched polypropylene film (# 25CP GHC manufactured by Tosello Co., Ltd.) was also obtained.

Comparative Examples 3 and 4 Vinylidene chloride copolymer emulsion (trade name: Krehalon latex DoAX-, manufactured by Kureha Chemical Industry Co., Ltd.)
Water was added to 2) to adjust to 15% by weight. An amount of 1.0 g of this coating solution was applied to the deposition surface of the aluminum oxide deposited film used in Comparative Example 1 (Comparative Example 3) or the deposited surface of the silicon oxide deposited film used in Comparative Example 2 (Comparative Example 4).
/ M ^2, and dried in an oven at 90 ° C. for 10 seconds to obtain a laminated film. Furthermore, a non-stretched polypropylene film (# 25C manufactured by Tocelo Co., Ltd.)
A composite film dry-laminated with (PGHC) was also obtained.

Comparative Examples 5 and 6 An antistatic coating agent (manufactured by Konishi Co., Ltd., trade name: Bondip PA100) was mixed with a base agent / curing agent = 1/1 (weight ratio), and a mixed solvent of water / isopropanol was used. To adjust the resin concentration to 4% by weight. The coating amount of 0.2 g of this coating solution was applied to the vapor deposition surface of the aluminum oxide vapor-deposited film used in Comparative Example 1 (Comparative Example 5) or the silicon oxide vapor-deposited film used in Comparative Example 2 (Comparative Example 6). / M ²
And dried in an oven at 90 ° C. for 15 seconds to obtain a laminated film. Further, a non-stretched polypropylene film (# 25CP G manufactured by Tosero Co., Ltd.)
A composite film dry-laminated with HC) was also obtained.

The laminated films obtained in Examples and Comparative Examples were evaluated for oxygen permeability, water vapor permeability, ash test, and surface resistivity as follows.

Oxygen permeability: same pressure method (measurement machine: MORCON)
OXTRAN 2/20) at 20 ° C. and 80% RH. The unit is cc / m ² / day. Comparative Examples 1 and 2
Is a non-stretched polypropylene film (manufactured by Tocelo Co., Ltd.)
# 25CP GHC) and measured.

Moisture permeability: Dry-laminated with a non-stretched polypropylene film (# 25CP GHC manufactured by Tosello Co., Ltd.), and measured by using a bag method at 40 ° C. and 90% RH. The unit is g / m ² / day.

Ash test (Evaluation method for practicality of antistatic): Non-stretched polypropylene film (# 2 manufactured by Tocelo)
After dry lamination with 5CP GHC) and rubbing with polyester fiber 10 times, adhesion of ash was examined. Condition is 2
Performed at 0 ° C. and 50% RH. Evaluation: ○: No adhesion ×:
Violent adhesion.

Surface specific resistance: Ultra high resistance meter (ADVANTEST
R8340A), the coating surface was measured at 20 ° C. and 60% RH. The unit is Ω.

Table 1 shows the results. As is clear from the table, Comparative Example 1 has insufficient moisture-proof properties, gas barrier properties, and antistatic properties. In Comparative Example 3, the moisture-proof property and the gas barrier property were good, but the antistatic property was poor. Comparative Example 5 has an antistatic effect, but has a lower moisture-proof property and gas barrier property than Comparative Example 1. The laminated film of Example 1 has gas barrier properties,
High antistatic effect. Further, the barrier property was improved as compared with Comparative Example 3.

[0047]

[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B65D 65/18 B65D 65/18

Claims (6)

[Claims] (1) at least one surface of (a) of a substrate film is coated with a barrier resin layer (c) via a transparent inorganic vapor deposition layer (b), and further on the barrier resin layer (c); A transparent laminated film provided with an antistatic layer (d). 2. The laminated film according to claim 1, wherein a heat seal layer is further laminated on the antistatic layer (d). 3. The laminated film according to claim 1, wherein the inorganic vapor-deposited layer (b) having transparency is aluminum oxide or silicon oxide. 4. The laminated film according to claim 1, wherein the barrier resin layer (c) is a vinylidene chloride copolymer. 5. The laminated film according to claim 1, wherein the antistatic layer (d) comprises a substance having an antistatic property. 6. The antistatic layer (d) is an adhesion primer composed of a crosslinkable polymer having antistatic induction properties, wherein the crosslinkable polymer has at least a carboxyl group and a quaternary ammonium base in a side chain. The laminated film according to claim 1, wherein the laminated film is a polymer having the following formula: