JPH11240117A - Vapor-deposited polypropylene film for packaging and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize a vapor-deposited film and to enhance close adhesion and gas barrier properties in a vapor deposited polypropylene film for packaging food, medicines or the like. SOLUTION: In a vapor-deposited polypropylene film 1 for packaging wherein a vapor deposition film 20 comprising silicon oxide or the like is laminated to the single surface of a polypropylene film 10, the half value width of the Cls waveform separation spectrum of the polypropylene main chain C-C bond of the interfacial layer of the polypropylene film on the surface side of the vapor deposition film 20 is set to 1.30-1.15 eV. This film is produced by continuously applying low temp. plasma treatment and the formation of the vapor deposition film to the single surface of the polypropylene film in the same vapor deposition machine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor-deposited polypropylene film suitable for packaging foods and medicines, and more particularly to a vapor-deposited polypropylene film for gas barrier packaging.

[0002]

2. Description of the Related Art Conventionally, a polypropylene film is excellent in transparency, moisture-proof property, mechanical strength (strength), etc., and is suitably used for packaging of foods and the like, and in particular, a vinylidene chloride resin is coated on the surface. Polypropylene films have been widely used as films having excellent oxygen barrier properties and water vapor barrier properties. However, due to the recent widespread use of packaging materials, higher levels of oxygen barrier properties and water vapor barrier properties have been required, and chlorine-based gas generated during incineration has caused corrosion of incinerators and air pollution. Recently, vinylidene chloride coated polypropylene films tend to be repelled due to environmental problems and the like, and there has been a strong demand for a film that can be used instead.

In order to meet this demand, a vapor-deposited polypropylene film for packaging, in which a thin film of an inorganic compound (metal oxide or the like) such as silicon oxide or aluminum oxide is provided on a polypropylene film by a vacuum vapor deposition method or the like, has been developed.

Here, a conventional vapor-deposited polypropylene film for packaging is obtained by subjecting a polypropylene film to a dry surface treatment such as a corona treatment or a plasma treatment and then applying a vapor-deposited film of an inorganic compound (eg, a metal oxide) to the polypropylene film. There is a problem that the effect changes and the barrier properties and adhesion vary. In addition, UV light (U
V) Irradiation treatment, electron beam (EB) treatment, flame treatment, chemical treatment and the like have a problem that the treatment degree becomes excessive, destroys the surface structure of the polypropylene film, and deteriorates the adhesion.

[0005] As described above, in the case where the polypropylene film is used as the base and the inorganic compound layer is provided thereon, the inorganic film is more inorganic than the polyester film such as polyethylene terephthalate (PET). The adhesion between the compound layer and the base film is also poor, and the barrier properties against oxygen and water vapor are inferior. It is difficult to obtain a material that can withstand practical use, and the development is behind that of a PET film-based film. .

Therefore, recently, a polypropylene film base has been developed.
Many studies have been conducted to improve the adhesion and barrier properties of steel. For example, JP-A-7-329258 discloses that a layer B made of a mixed resin of a polypropylene copolymer and an ethylene copolymer is laminated on an layer A made of crystalline polypropylene, and a metal oxide is formed on the layer B. Japanese Patent Application Laid-Open No. 7-329235 discloses a layer containing a syndiotactic polypropylene polymer on an A layer mainly containing a polypropylene polymer.
A structure in which layers are stacked and a metal oxide is provided on the B layer is disclosed. Although it is not limited to a polypropylene film, Japanese Patent Publication No. 63-54541 discloses 2
By providing an adhesive layer made of a random copolymer of ethylene and an α-olefin on a base layer of an α-olefin having up to 6 carbons, and by providing a metal layer on the adhesive layer, An improved adhesiveness between the base layer and the metal layer is disclosed.

However, the invention described in the above-mentioned application is:
In each case, the heat resistance (softening point, melting point, etc.) of the polypropylene film surface is reduced. If the heat resistance of the surface is reduced, the heat load when the inorganic compound layer is provided by a vacuum deposition method or the like is reduced. The surface is softened, and a part of the particles forming the inorganic compound layer is taken in to form a film, so that the adhesiveness is improved, but stress is applied to the inorganic compound layer when the softened outermost surface is cooled and solidified again. As a result, the barrier property was not improved, and on the contrary, it deteriorated.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art. It is an object of the present invention to provide a vapor-deposited polypropylene film for packaging foods and medicines, wherein the vapor-deposited film is stable. An object of the present invention is to provide a vapor-deposited polypropylene film for packaging having adhesion and gas barrier properties.

[0009]

In order to achieve the above object, the present invention first provides a method in which a deposited film made of a metal or a metal oxide is laminated on at least one surface of a polypropylene film. The polypropylene main chain C of the interface layer of the polypropylene film in contact with the vapor-deposited film
-Half width of C1s waveform separation spectrum of C bond is 1.3.
This is a vapor-deposited polypropylene film for packaging, which is characterized by having a voltage of 0 to 1.15 eV.

[0010] In the invention of claim 2, the vapor-deposited film is made of a vapor-deposited polypropylene film for packaging according to claim 1, wherein the vapor-deposited film is made of silicon oxide, aluminum oxide, magnesium oxide or aluminum. It is.

[0011] In the invention of claim 3, the low-temperature plasma treatment and the formation of a deposited film are continuously performed on one side of the polypropylene film in the same vapor deposition machine. This is a method for producing a vapor-deposited polypropylene film for packaging.

[0012]

Embodiments of the present invention will be described below. As shown in FIG. 1, the vapor-deposited polypropylene film for packaging according to the present invention has a vapor-deposited film (20) made of metal or metal oxide laminated on at least one surface of a polypropylene film (10). (2
0) a vapor-deposited polypropylene film for packaging, comprising a thermo-adhesive resin layer (40) laminated on a coating layer (30) alone or on the same;
Vapor-deposited polypropylene film (1) for packaging in which the half-width of the C1s waveform separation spectrum of the polypropylene main chain CC bond of the interface layer (10a) of the polypropylene film (10) in contact with is 1.30 to 1.15 eV. is there.

The vapor-deposited film (20) is a vapor-deposited polypropylene film (1) for packaging made of silicon oxide, aluminum oxide, magnesium oxide or aluminum.

As a method for producing the above-mentioned vapor-deposited polypropylene film for packaging (1), as shown in FIG. 2, one side of the above-mentioned polypropylene film (10) is subjected to low-temperature plasma treatment in a vapor-deposition apparatus (100), and is continuously processed. To form a deposited film (20). More specifically, the unwinding roll (62) unwinds the polypropylene film (10).
And a take-up roll (64) via a cooling drum (60)
And a low-temperature plasma processing gas (for example, carbon dioxide gas) is introduced into the low-temperature plasma processing apparatus (70) in the upper vacuum chamber (102), and the polypropylene film (10) is unwound from the unwinding roll (62). While the low-temperature plasma processing is performed by the low-temperature plasma processing apparatus (70), the deposition processing is continuously performed by the evaporation source (22) such as silicon oxide in the lower vacuum chamber (64).
One side of a polypropylene film (10) has a vapor-deposited film (2
0).

Subsequently, in order to form a vapor-deposited polypropylene film for packaging of foods and the like, foods and the like come into direct contact only with a film formed by depositing a metal oxide or the like on the polypropylene film (10). Vapor deposition film (2
0), the coating layer (30) made of an anchoring agent or the like as shown in FIG. Generally, a vapor-deposited polypropylene film (1) for packaging is obtained by applying a heat-sealable resin layer (40) such as polyethylene which is heat-sealable through (or alone).

The vapor-deposited polypropylene film for packaging obtained above has a vapor-deposited film (20) having stable adhesiveness and gas (oxygen or water vapor) barrier properties, and also has improved productivity.

Hereinafter, the present invention will be described in detail including materials used for the vapor-deposited polypropylene film for packaging according to the present invention. First, the polypropylene film (10) may be any of a biaxially oriented polypropylene film (OPP) and a non-oriented polypropylene film, but a biaxially oriented polypropylene film is preferably used from the viewpoint of mechanical stability and the like. Although the thickness is not particularly limited, it is 5 to 50 in view of suitability as a packaging material, that is, suitability for processing including lamination and lamination with other layers (such as films).
The range is preferably 0 μm, and more preferably 6 to 30 μm, depending on the ease of winding and the application.

The structure of the interface layer (10a) in contact with the deposited film (20) of the polypropylene film (10) is as follows:
When the waveform separation analysis of the interface layer (10a) is performed by X-ray photoelectron spectroscopy (XPS), the full width at half maximum (FWHM) of the C1s waveform separation spectrum of the polypropylene main chain CC bond is 1.30 to 1.15 eV. There is a vapor deposition film (20)
Is preferable for improving the stable adhesion and the gas barrier property of oxygen and water vapor, and 1.25 to 1.20 eV is a more preferable value. When the half width is larger than 1.30 eV, adhesion and gas barrier properties are poor, and
If it is less than 5 eV, the adhesiveness and gas barrier properties are similarly deteriorated, which is not preferable.

The conditions for the waveform separation analysis (measurement) of the interface layer (10a) are as follows: an X-ray source MgKα, an output of 100 W, and an energy resolution of a half width of an Ag3d5 / 2 peak of 0.90 ± 0.01 eV. It is possible to analyze the types of atoms in the depth direction of the interface layer (10a) of the polypropylene film (10) in the depth direction and the bonding state of the atoms bonded to the atoms.

Examples of the deposited film (20) include metals such as silicon, aluminum, titanium, zinc, zirconium, magnesium, strontium, copper and iron, and oxides, nitrides, sulfides and fluorides thereof. For packaging, aluminum and silicon oxides, aluminum oxides and magnesium oxides are preferably used.

As a discharge electrode for the low-temperature plasma processing, a direct current (DC) magnetron electrode is preferably used in terms of stability and processing strength. In performing low-temperature plasma processing using this electrode, a vapor deposition apparatus (100) is used. Examples of the gas to be introduced into the low-temperature plasma processing apparatus (70) in the upper vacuum chamber (104) include rare gases such as argon, oxygen, nitrogen, carbon dioxide, or a mixed gas thereof. From the viewpoint, carbon dioxide gas is preferably used.

The low-temperature plasma treatment can be performed stably by, for example, introducing carbon dioxide gas under a pressure of about 5.0 × 10 ⁻² Pa.

The processing degree of the low-temperature plasma processing is represented by power per unit area (W / m ² ) × unit time (min), preferably 10 to 1000 W · min / m ^2.
The vicinity of 00 W · min / m ² is a preferable treatment degree due to the improvement of the adhesion and the gas barrier property of the vapor-deposited film (20). However, since the treatment state changes depending on the distance between the polypropylene and the electrode in each apparatus, It is not specified.

When performing the deposition process following the low-temperature plasma process, an oxygen gas or a mixed gas of an oxygen gas and a rare gas such as argon or helium is placed in a lower vacuum chamber (102) of the deposition apparatus (100). The metal or its oxide is evaporated in an oxidizing atmosphere with
2) to form a vapor-deposited film (20) on the polypropylene film (10).

As a method for forming the above-mentioned deposited film (20), a method of directly depositing a metal oxide or the like, a reactive deposition method of evaporating the metal and reacting it with oxygen or the like in vapor, or an ion plating method. No problem. Similarly, in the case of a CVD method such as a sputtering method or a reactive sputtering method, a thermal CVD method, a plasma CVD method, or the like can be freely selected.

The thickness of the deposited film (20) is slightly different depending on the kind of the metal or its oxide, but it is generally from 5 to 5.
It is desirable to be within the range of 500 nm. This means that if it is thinner than 5 nm, the deposited film (20) does not form a film, and sufficient oxygen barrier properties and water vapor barrier properties cannot be exhibited, and if it is thicker than 500 nm, the internal stress of the deposited film (20) causes This is because the film is peeled off and the gas barrier property is reduced, and the metal oxide vapor-deposited film (20), which requires transparency, may be reduced in transparency.

[0027]

Next, the present invention will be described in detail with reference to examples. <Example 1> A vapor-deposited polypropylene film for packaging was produced under the following conditions. 1) Polypropylene film (10)-an untreated biaxially stretched polypropylene film having a thickness of 20 µm in a rolled shape. 2) evaporated film (20)-thickness 5 by electron beam heating method
A 0 nm silicon oxide deposited film was continuously formed on the polypropylene film (10). 3) A thermo-adhesive resin layer (40)-a non-stretched polypropylene film having a thickness of 30 µm is formed by dry lamination,
The coating layer (30) was omitted. 4) Low temperature plasma treatment-titanium cathode, DC magnetron method, pressure of the upper vacuum chamber (104) in the vapor deposition device (100) at the time of introducing carbon dioxide gas is 5.0 × 10 ^-2 Pa.
The plasma treatment was performed at 300 W · min / m ² below.

Comparative Example 1 A vapor-deposited polypropylene film for packaging was produced under the same conditions as in Example 1 except that the low-temperature plasma treatment was not performed.

Comparative Example 2 A vapor-deposited polypropylene film for packaging was produced under the same conditions as in Example 1 except that the treatment degree of the low-temperature plasma treatment was 2000 W · min / m ² .

Example 2 A vapor-deposited polypropylene film for packaging was produced under the same conditions as in Example 1 except that aluminum oxide was used for the vapor deposition film (20).

Comparative Example 3 A vapor-deposited polypropylene film for packaging was produced under the same conditions as in Comparative Example 1 except that aluminum oxide was used for the vapor-deposited film (20).

Comparative Example 4 A vapor-deposited polypropylene film for packaging was produced under the same conditions as in Comparative Example 2 except that the deposited film (20) was changed to aluminum oxide.

Example 3 A vapor-deposited polypropylene film for packaging was produced under the same conditions as in Example 1 except that the vapor-deposited film (20) was made of aluminum.

Comparative Example 5 A vapor-deposited polypropylene film for packaging was produced under the same conditions as in Comparative Example 1 except that the vapor-deposited film (20) was made of aluminum.

Comparative Example 6 A vapor-deposited polypropylene film for packaging was produced under the same conditions as in Comparative Example 2 except that the vapor deposition film (20) was made of aluminum.

With respect to the vapor-deposited polypropylene films for packaging obtained in Examples 1 to 3 and Comparative Examples 1 to 6, the structure of the interface layer (10a) of the polypropylene film (10) was subjected to waveform separation analysis under the following conditions, and the results were obtained. Are shown in Table 1. At the same time, the peel strength indicating the adhesiveness, the oxygen permeability and the water vapor permeability indicating the gas barrier properties were measured, and the results are shown in Table 1. [Waveform separation analysis] X-ray photoelectron spectroscopy (XPS), using a JSP-90MXVmicro (manufactured by JEOL Ltd.) as an apparatus, peeling off at the interface between the vapor-deposited polypropylene film (10) and the vapor-deposited film (20) for packaging. Ag (10a) interface layer of polypropylene film (10)
The 3d5 / 2 peak was measured under the condition of a half width of 0.90 ± 0.01 eV.
The half-width (FWHM) of the -C bond was determined. [Peeling strength] The vapor-deposited polypropylene film for packaging (sample width 15 mm) obtained above was subjected to T-peeling (peeling speed 30) using a tensile tester (Tensilon RTM250).
0 mm / min), and used as a substitute property of the adhesion. The unit is g / 15 mm. [Oxygen permeability] MOCON: 25 ° C.10 by the MOCON method using PERMATRAN (manufactured by Modern Control)
It is measured under 0% and its unit is g / m ² · day. [Water vapor permeability] MOCON: OX-TRAN (Modern Control Co., Ltd.) 40 ° C / 90% by Mocon method
Measured below, the unit is cc / m ² · day.

[0037]

[Table 1]

From Table 1, the half-width (FWHM) of the waveform separation spectrum in the interface layer (10a) of the vapor-deposited polypropylene film for packaging obtained in Examples 1 to 3 was 1.21.
It was around eV and was stable and excellent in adhesion and gas barrier properties irrespective of the type of the deposited film (20).
On the other hand, the FWHM of the vapor-deposited polypropylene films for packaging obtained in Comparative Examples 1, 3, and 5 was around 1.35 eV, and the adhesion and gas barrier properties were significantly poor regardless of the type of the vapor-deposited film (20). Was. Comparative Example 2,
The FWHM of the vapor-deposited polypropylene film for packaging obtained in 4 and 6 is around 1.12 eV, and the adhesion and gas barrier properties are irrespective of the type of the vapor-deposited film (20).
It was inferior to three.

[0039]

As described above, the present invention has the following effects. That is, a vapor-deposited film (20) made of metal or metal oxide is laminated on one side of the polypropylene film (10), and the heat-adhesive resin layer (4) is laid on the vapor-deposited film via a coating layer (30) or alone.
0), the polypropylene main chain CC of the interfacial layer (10a) of the polypropylene film in contact with the vapor-deposited film.
The half width of the combined C1s waveform separation spectrum is 1.30 to
1.15 eV, the polypropylene film (1
It is possible to provide a vapor-deposited polypropylene film for packaging excellent in adhesion between the film (0) and the vapor-deposited film (20) and gas barrier properties of the film.

The polypropylene film (1)
0), one side is subjected to low-temperature plasma treatment in the same vapor deposition machine, that is, in-line, and a vapor deposition film (20) is continuously applied, so that the polypropylene film (10) and the vapor deposition film (2)
0) It is possible to provide a vapor-deposited polypropylene film for packaging, which is more stable and excellent in the adhesiveness and gas barrier property of the film and has high production efficiency. Therefore, the present invention
It has excellent practical effects in applications such as food and pharmaceutical packaging.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a vapor-deposited polypropylene film for packaging according to an embodiment of the present invention in a side cross section.

FIG. 2 is a schematic diagram illustrating an example of an apparatus for producing a vapor-deposited polypropylene film for packaging according to the present invention.

[Explanation of symbols]

 1 evaporated polypropylene film for packaging 10 polypropylene film 10a interface layer 20 evaporated film 22 evaporation source 22a evaporation flow 24 crucible 30 coating layer 40 thermal adhesive resin layer 60 cooling drum 62 unwinding roll 64 winding roll 70 low-temperature plasma processing apparatus 100 vapor deposition apparatus 102 lower vacuum chamber 104 upper vacuum chamber

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C23C 14/20 C23C 14/20 Z

Claims (3)

[Claims] 1. A vapor-deposited polypropylene film for packaging in which a vapor-deposited film made of metal or metal oxide is laminated on at least one surface of a polypropylene film, wherein a polypropylene main chain C of an interface layer of the polypropylene film in contact with the vapor-deposited film is provided. A vapor-deposited polypropylene film for packaging, wherein the half-width of a C1s waveform separation spectrum of -C bond is from 1.30 to 1.15 eV. 2. The vapor-deposited polypropylene film for packaging according to claim 1, wherein the vapor-deposited film is made of silicon oxide, aluminum oxide, magnesium oxide or aluminum. 3. The vapor-deposited polypropylene film for packaging according to claim 1, wherein low-temperature plasma treatment and formation of a vapor-deposited film are successively performed on one surface of the polypropylene film in the same vapor deposition device. Production method.