JPH06106669A - Package - Google Patents

Abstract

PURPOSE:To provide a package composed of a gas barrier film excellent in bending resistance and food preservability. CONSTITUTION:A package is entirely or partially constituted of a gas barrier film wherein a transparent membrane consisting of 50-80wt.% of magnesium oxide and silicon oxide is provided to at least one surface of a plastic base material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a package which has excellent gas barrier properties and is suitable for long-term storage of foods, pharmaceuticals, electronic parts and the like.

[0002]

2. Description of the Related Art As a package having an excellent gas barrier property, a laminate of aluminum on a plastic film, a coat of vinylidene chloride or an ethylene vinyl alcohol copolymer, and a thin film of silicon oxide, aluminum oxide, etc. Laminated packages are known.

[0003]

The conventional gas barrier film has the following problems. Alminim laminated products have excellent economical efficiency and gas barrier properties, but have the drawback that the contents are not visible during packaging because they are opaque. Furthermore, if aluminum is included as part of the packaging structure, plastic film or paper There is also a problem that collection and reuse (recycling) is not possible. Those containing vinylidene chloride or ethylene vinyl alcohol copolymer as a part of the constitution of the package have insufficient gas barrier properties against water vapor, oxygen, etc., and the storage period of the package is short. Further, vinylidene chloride-based ones are easily decomposed by heat and difficult to recycle, and there is also a concern that the generation of chlorine gas during incineration may affect the global environment. The ethylene vinyl alcohol type has a low oxygen barrier property at high humidity and a short storage period.

Japanese Patent Publication No. 51-48511 discloses a synthetic resin.
Six Oy (eg SiO ₂) Vapor deposited gas
A barrier film has been proposed, but it has a gas barrier property.
A good SiOx system (x = 1.3-1.8) has a brown color
The coating is brittle, and it can be used as part or all of the composition.
Gas barrier properties when the package is handled harshly
Has the drawback of being significantly reduced. Also, MgO and S
iO₂Moisture-permeable transparent synthetic resin body vapor-deposited with
As found in JP-A-61-297137
Although some have been obtained, this barrier film is a water vapor barrier.
Although it has excellent rear properties, it has poor oxygen barrier properties. This
When the film is used as part or all of the packaging structure
Is sufficient to protect the contents from oxidation and preserve it for a long time.
However, it has both oxygen barrier and water vapor barrier properties.
It cannot be a package that is equipped and can withstand harsh handling.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a package having a gas barrier film which is excellent in oxygen and water vapor barrier properties, has high flex resistance, and is economically advantageous, as a part or the whole of the constitution. Is intended to be provided. That is, the present invention is characterized in that a thin film having a composition mainly composed of magnesium oxide and silicon oxide is provided on at least one surface of a plastic substrate, and the thin film contains 50 to 80% by weight of magnesium oxide. The present invention relates to a packaging body having the gas barrier film as a whole or a part of the constitution.

The plastic substrate referred to in the present invention is a film obtained by melt-extruding an organic polymer and, if necessary, stretching, cooling and heat setting in the longitudinal direction and / or the width direction, As the organic polymer, polyethylene, polypropylene, polyethylene terephthalate, polyethylene-2,6-naphthalate, nylon 6, nylon 4,
Examples thereof include nylon 66, nylon 12, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, wholly aromatic polyamide, polyamideimide, polyimide, polyetherimide, polysulfone, polyphenylene sulfide, and polyphenylene oxide. Further, these (organic polymer) organic polymers may be copolymerized or blended with a small amount of another organic polymer.

Further, known additives such as an ultraviolet absorber, an antistatic agent, a plasticizer, a lubricant and a coloring agent may be added to the organic polymer, and the transparency thereof is not particularly limited. However, when used as a transparent gas barrier film, a film having a transmittance of 50% or more is preferable. The plastic substrate in the present invention may be subjected to corona discharge treatment, glow discharge treatment, or other surface roughening treatment prior to laminating thin film layers, as long as the object of the present invention is not impaired. Well, well-known anchor coat treatment, printing, and decoration may be applied. The thickness of the plastic substrate in the present invention is preferably in the range of 5 to 500 μm, more preferably 8 to 300 μm.

It is considered that the magnesium oxide / silicon oxide thin film is composed of a mixture of magnesium oxide and silicon oxide, a compound, or the like. The magnesium oxide referred to here is composed of a mixture of various magnesium oxides such as Mg, MgO, and MgO ₂ , and the content ratio of each in magnesium oxide varies depending on the preparation conditions. It is considered that silicon oxide is composed of Si, SiO, SiO _{2 and the} like, and the ratio of these also differs depending on the forming conditions. The ratio of magnesium oxide in the thin film in the present invention is 50.
It is preferably not less than 80% by weight and more preferably not less than 55% by weight and not more than 75% by weight. Further, a small amount (up to 3% with respect to all the components) of other components may be contained in this component as long as the characteristics are not impaired. Although the thickness of the thin film is not particularly limited, it is preferably 50 to 8000 Å, more preferably 70 to 5,000 Å, from the viewpoint of gas barrier property and flexibility.

A thin layer containing magnesium oxide or silicon oxide as a main component is laminated on at least one surface of such a plastic substrate. Various methods are known for forming such an inorganic thin film, and in the present invention, Is not particularly limited. For example, vacuum deposition method, sputtering method,
PVD method (physical vapor deposition method) such as ion plating,
Alternatively, a CVD method (chemical vapor deposition method) or the like is appropriately used. In the vacuum vapor deposition method, MgO and SiO ₂ or MgO and Si are used as the vapor deposition source material, and resistance heating, high frequency induction heating, electron beam heating or the like can be used as the heating method. Further, as the reactive gas, oxygen, nitrogen, water vapor, or the like may be introduced, or a reactive vapor deposition method using means such as ozone addition or ion assist may be used. Further, the production conditions may be changed as long as the object of the present invention is not impaired by applying a bias or the like to the substrate, raising the substrate temperature, or cooling. Spatter
The same applies to other preparation methods such as the CVD method and the CVD method.

The package in the present invention is a package in which a gas barrier film having a thin film of a composition mainly composed of magnesium oxide and silicon oxide is provided on at least one surface of a plastic substrate as a part or the whole of the constitution. The body,
The gas barrier film as it is or laminated with another organic polymer film or paper and molded into a package such as a container, bag or paper carton. Next, the present invention will be described with reference to examples.

[0011]

EXAMPLE As a vapor deposition source, particulate MgO having a size of about 3 to 5 mm (purity 99.5%) and SiO ₂ (purity 9) were used.
9.5%) was used to form a magnesium oxide / silicon oxide-based gas barrier thin film on a 12 μm-thick PET film (Toyobo Co., Ltd .: E5007) by an electron beam vapor deposition method. The film thickness is 700, 1500Å, and
~ 6 were produced.

Further, with respect to this composite film on PET, an unstretched polypropylene film (C
The PP film) was dry-laminated using a two-component curing type polyurethane adhesive (thickness 2 μm) to obtain a plastic film for packaging. The gas barrier film thus obtained and the oxygen barrier property after the bending fatigue resistance test were measured. The methods for measuring oxygen and water vapor permeability and the flex fatigue resistance test are shown below.

Method for measuring oxygen permeability The oxygen permeability of the prepared gas barrier film is measured by an oxygen permeability measuring device (Modern Controls OX-TRA).
N100). -Measurement method of water vapor transmission rate The water vapor transmission rate of the prepared gas barrier film was measured by a water vapor transmission rate tester (L80-4000 type manufactured by Lissie).
Was measured using. -Test method for flex fatigue resistance (hereinafter gelbo property) Flex fatigue resistance was evaluated using a so-called gelbo flex tester (manufactured by Rigaku Kogyo Co., Ltd.). The condition is (MIL-B131H) 112 inch x 8 inc.
The sample piece of h was made into a cylindrical shape with a diameter of 3 (1/2) inch,
Both ends are held, the initial gripping interval is set to 7 inches, a twist of 400 degrees is applied at a stroke of 3 (1/2) inch, and this reciprocating motion is repeated 40 times / min.
At a temperature of 20 ° C. and a relative humidity of 65%.
The oxygen transmission rate measured in this way was extremely excellent, about 1 cc. Furthermore, the result after 100 gelvo tests was only about 1 cc increase, and a gas barrier film having excellent gelbo characteristics was obtained.

[0014]

Comparative Example As a comparative example, SiO ₂ , MgO + SiO ₂
(30:70), MgO + SiO ₂ (90:10), M
A metal oxide having a composition of gO, SiO, Al ₂ O ₃ , and Al and a metal were vapor-deposited on a PET film in the same manner as in the example, and laminated with CPP. The oxygen permeability of the film of the comparative example is higher than that of the example as shown in Table 1.
Further, when the gel film tester was bent 100 times, the oxygen barrier property of the film of Comparative Example was significantly lowered. The film of Example 4, namely MgO (70%) and SiO ₂ (30
%) Was vapor-deposited on a PET film having a thickness of 12 μm for 700Å, and a CPP film having a thickness of 40 μm was dry-laminated with a urethane adhesive, and a non-vapor-deposited PET surface was dry-laminated with a printed OPP film. 30cm by heat-sealing
A bag with a size of × 20 cm was produced. The bag was bent 100 times with a gel bot tester, then potato chips were packaged, and the opening was heat-sealed to seal the bag. These were left in a room at 25 ° C. and 65% RH for 6 months, and a taste test was conducted after the standing, but the color, taste and dryness of the potato chips were not changed.

Similarly to the films of Comparative Examples 1 to 7, the printed OPP was dry-laminated to produce a bag of 30 cm × 20 cm, which was bent 100 times with a gel votester, and then potato chips were put therein and adhered thereto at 25 ° C. The sample was left in a room of 65% RH for 6 months and a taste test was conducted. In each case, a slight discoloration, an odor of oxidation and moisture absorption were observed, and the crispy feeling was deteriorated.

The film of Example 4, namely MgO (55
%) And SiO ₂ (45%) were vapor-deposited on a 12 μPET film in an amount of 1500 Å, and a 40 μC thick CPP film was dry-laminated, and further laminated on a paper laminated with polyethylene (PE). In this way, PE / paper / MgO-SiO ₂ vapor deposited PET / C
A sheet of PP construction was produced and heat sealed to form a paper carton. The oxygen permeability of this paper carton was 0.5 cc, which was equivalent to that of a conventional paper carton laminated with a 7 μm aluminum foil, and the liquid food could be stored for 6 months without oxidative deterioration. Further, although it is difficult to recycle the paper from the conventional paper carton laminated with 7 μm aluminum foil, the paper could be easily recycled from the paper carton of the example.

[0017]

As a composition of the gas barrier layer, a transparent thin film having a composition of magnesium oxide and silicon oxide is provided, and 50 to 80% by weight of magnesium oxide is contained in the composition of the thin film. As a result, a package having excellent gas barrier properties and excellent bending resistance (gelbo property) could be obtained.

[0018]

[Table 1]

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location B65D 85/50 Z 7445-3E C08J 7/04 P (72) Inventor Yoshiharu Morihara 2 Katata, Otsu, Shiga Prefecture No. 1 Toyobo Co., Ltd., Research Institute (72) Inventor Toru Kotani 1-1, Katata, Otsu City, Shiga Prefecture Toyobo Co., Ltd., Research Institute (72) Inventor Yozo Yamada 2-chome Katata, Otsu, Shiga Prefecture No. 1 Toyobo Co., Ltd. Research Institute

Claims (1)

[Claims] 1. A thin film having a composition mainly composed of magnesium oxide and silicon oxide is provided on at least one surface of a plastic base material, and 50 to 80% by weight of magnesium oxide is contained in the composition of the thin film. A package having a gas barrier film as a whole or a part of the structure.