JP3228362B2 - Packaging material and package for dried food - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention has excellent gas barrier properties,
Snack foods such as potato chips and popcorn, rice crackers such as rice crackers and oysters, instant ramen and sprinkles, shaved knots, dried products such as laver, green tea, coffee, tea, etc., flour, rice The present invention relates to a packaging material and a package for dried foods suitable for preservation of cereals such as wheat and wheat.

[0002]

2. Description of the Related Art As a packaging material and a package for dried food having excellent gas barrier properties, various plastic films laminated thereon are used. For example, OPP
(Stretched polypropylene) film and PE (polyethylene) film, or PET (polyester) film and CPP (unstretched polypropylene) film laminated. Further, using a packaging material obtained by laminating a PET film or a film obtained by coating vinylidene chloride or an ethylene vinyl alcohol copolymer on a PET film or by laminating with a PE or CPP film, , Trays, etc. are manufactured and used. Recently, a film using a thin film of silicon oxide or the like as a barrier film has been proposed.

[0003]

The conventional packaging material and package for a dried food have the following problems. Aluminum foil or aluminum-deposited aluminum foil has excellent gas barrier properties, but is opaque and has a drawback that the contents at the time of packaging cannot be seen.
In addition, when aluminum is included in a part of the structure of the packaging material for dried food and the package, there is a problem that the plastic film cannot be collected and reused. Those containing vinylidene chloride or ethylene vinyl alcohol copolymer in a part of the composition of the packaging material for dry food and the package have insufficient gas barrier properties such as water vapor and oxygen,
The storage period of the contents is short. In addition, vinylidene chloride is easily thermally decomposed and is not easily recycled.
There are also concerns about the impact on the global environment, such as the generation of chlorine gas during incineration. In addition, although the ethylene vinyl alcohol system has excellent barrier properties at the time of drying, under high humidity, the oxygen barrier properties are significantly reduced and the storage period is shortened.

Japanese Patent Publication No. 51-48511 discloses a synthetic resin.
Si on body surface_xO_y(Eg SiO _TwoGas deposited)
Although barrier films have been proposed,
Good SiO_xThe system (x = 1.3-1.8) has a brown color
And its coating is brittle, and it
Handling of dry food packaging materials and packaging
Gas barrier property is greatly reduced
There is a point. Aluminum oxide deposited film
(JP-A-62-101428)
However, the initial oxygen barrier properties are not so high. More bending
Oxygen barrier property is greatly deteriorated when dried,
When part or all of the composition of the packaging material and package
It is sufficient for protecting the contents from oxidation and for long-term storage
However, it has both oxygen barrier properties and water vapor barrier properties.
Fortunately, it cannot withstand severe handling.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a packaging material for dry foods comprising a gas barrier film part or all of which is excellent in gas barrier properties, high in bending resistance, and economically advantageous. And packaging are not provided. That is, the present invention is characterized in that a thin film having a composition mainly composed of aluminum oxide and silicon oxide is provided on at least one surface of a plastic base material, and 20 to 99% by weight of aluminum oxide is contained in the composition of the thin film. A dry food packaging material and a package having a gas barrier film as a whole or a part of the structure, and preferably, a gas barrier film characterized by the specific gravity of the thin film satisfying the following formula. It is a packaging material and a package for dried food which are all or a part. D = 0.01A + b (where D: specific gravity of the thin film, A: weight% of aluminum oxide in the thin film, 1.6 ≦ b ≦ 2.
2)

The plastic substrate referred to in the present invention is a film obtained by melt-extruding an organic polymer and stretching, cooling, and heat setting in the longitudinal direction and / or the width direction as necessary. Organic polymers include polyethylene, polypropylene, polyethylene terephthalate, polyethylene-2,6-naphthalate, nylon 6, nylon 4,
Nylon 66, nylon 12, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, wholly aromatic polyamide, polyamide imide, polyimide, polyether imide, polysulfone, polyphenylene sulfide, polyphenylene oxide and the like. These (organic polymer) organic polymers may be copolymerized or blended in small amounts with other organic polymers.

Further, known additives such as an ultraviolet absorber, an antistatic agent, a plasticizer, a lubricant,
A coloring agent or the like may be added, and the transparency 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 film of the present invention may be subjected to corona discharge treatment, glow discharge treatment, or other surface roughening treatment prior to laminating the thin film layer, as long as the object of the present invention is not impaired. Also, a known anchor coat treatment, printing, and decoration may be applied. The thickness of the plastic film of the present invention is preferably in the range of 5 to 500 μm, more preferably 8 to 300 μm.

It is considered that the aluminum oxide / silicon oxide thin film is composed of a mixture or a compound of aluminum oxide and silicon oxide. The aluminum oxide here is composed of a mixture of various aluminum oxides such as Al, AlO, and Al ₂ O ₃ , and the content of each of the aluminum oxides in the aluminum oxide differs depending on the production conditions. Silicon oxide is considered to be composed of Si, SiO, SiO _{2 and the} like, and their ratios also differ depending on the preparation conditions. In the present invention, the ratio of aluminum oxide in the thin film is 20% by weight or more and 99% by weight or less, preferably 30% by weight or more and 95% by weight or less. Also, this component may contain a trace amount (up to 3% of all components) of other components as long as the characteristics are not impaired. The thickness of the thin film is not particularly limited, but is preferably from 50 to 8000 A, more preferably from 70 to 5000 A, from the viewpoint of gas barrier properties and flexibility.

In order to form such an aluminum oxide / silicon oxide based thin film, a vacuum evaporation method, a sputtering method, an ion
PVD method (physical vapor deposition method) such as ting, or C
A VD method (chemical vapor deposition method) or the like is appropriately used. For example,
In the vacuum evaporation method, Al ₂ O ₃ and SiO ₂ or a mixture of Al and SiO ₂ is used as an evaporation source material, and the heating method includes resistance heating, high frequency induction heating, electron beam heating, and the like. Can be used. Further, oxygen, nitrogen, water vapor, or the like may be introduced as a reactive gas, or reactive vapor deposition 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, such as applying a bias to the substrate, increasing the substrate temperature, or cooling. The same applies to other production methods such as a sputtering method and a CVD method. The product of the present invention may be used as it is, or may be used by laminating or coating another organic polymer film or a thin layer.

The specific gravity referred to in the present invention refers to the ratio of the mass of a substance occupying a certain volume at a certain temperature to the mass of a standard substance having the same volume (water at 4 ° C.). The measurement of specific gravity is
Normally, the mass and volume of the object may be measured, and the ratio of the mass to the same volume of water at 4 ° C. may be obtained. However, it is difficult to measure the volume in the measurement of the thin film of the present invention. Then, first, the thin film is peeled off from the substrate or only the substrate is dissolved to form a single film consisting of only the thin film.
It is desirable to use a specific gravity measurement method as described in 7112). For example, in the flotation method, a sample is immersed in a solution having a known specific gravity, and the specific gravity of the thin film can be measured from the flotation state. As this solution, a mixed solution of carbon tetrachloride and bromoform, methylene iodide, or the like can be used. The specific gravity value can also be measured by a density gradient tube method in which a single film is immersed in a solution having a continuous density gradient.

The relationship between the specific gravity of the thin film thus obtained and the weight percentage of aluminum oxide in the thin film is expressed by D
= 0.01A + b (D: specific gravity of the thin film, A: weight% of aluminum oxide in the thin film), when the value of b is less than 1.6, the structure of the aluminum oxide / silicon oxide thin film Becomes coarse and sufficient gas barrier properties cannot be obtained. Further, the value of the specific gravity of the thin film is a b value,
In the case of a region larger than 2.2, the initial gas barrier properties after film formation are excellent, but the film is too hard, the mechanical properties, particularly the gelbo properties, are inferior, and the gas barrier properties after treatment are greatly reduced. Not suitable for use as a conductive film. For the above reasons, the specific gravity of the aluminum oxide / silicon oxide thin film, which is preferable as a packaging material and a package for aquatic foods, is obtained by calculating the relationship between the specific gravity of the thin film and the aluminum oxide composition ratio in the thin film as D = 0.01A + b (D: thin film And the specific gravity of A: A: wt% of aluminum oxide in the thin film), the value of b is 1.6 to 2.2,
More preferably, it is 1.7 to 2.1. (Fig. 1)

The dry food packaging material of the present invention may be laminated using various films or papers according to the required characteristics of the contents to be packaged. A typical laminating composition is a gas barrier film (on PET). / PE, gas barrier film (on PET) / CPP, NY / gas barrier film (on PET) / PE, gas barrier film (NY
Top) / PE etc. are conceivable. As a laminating method,
Although there is no particular limitation, dry laminating, extrusion laminating and the like are preferred. Furthermore, it may be decorated or printed for explanation of the contents, or may be laminated with a design film or a reinforcing agent. Examples of the package according to the present invention include bags, lids, cups, tubes, standing packs, trays, and the like. There are no particular restrictions on the shape and type. , Three-way seals, four-way seals and the like can be used.
A gas barrier film is used as all or a part of the configuration of these packaging materials and packages. The contents to which the package for dried foods of the present invention can be applied include snacks such as potato chips and popcorn, rice crackers such as rice crackers and oysters, instant lamen and sprinkles, shaved knots, dried articles such as laver and green tea. , Coffee, tea, etc., and flour, rice, wheat, etc., grains, etc., and are not limited thereto.

Next, the present invention will be described with reference to examples.

Example 1 Flake-like Al ₂ O ₃ (purity 99.5%) and SiO _{2 having} a size of about 3 to 5 mm were used as evaporation sources.
(Purity: 99.9%), using electron beam evaporation method
μm thick PET film (Toyobo Co., Ltd .: 5100
0) An aluminum oxide / silicon oxide based thin film was formed thereon. The deposition conditions were such that the emission current of the electron gun (EB gun) was 1.2 A, the heating ratio was 30:10, and the composition ratio was Al ₂ O ₃ : SiO ₂ = 60: 40. The thickness of the deposited film is 500A (angstrom), laminated with PE (polyethylene) 30μm,
Example 1 was produced. The oxygen barrier property of this packaging film was measured. As comparative examples, 1-PET,
A film of -K-PET (vinylidene chloride PET film) -Al foil was laminated with PE (30 µm) in the same manner as in the example. This packaging film was also measured for oxygen barrier properties in the same manner as in the examples.

Next, a method for measuring the oxygen permeability will be described. -Oxygen transmission rate measurement method The oxygen transmission rate of the prepared gas barrier film is measured by an oxygen transmission rate measuring apparatus (OX-TRANS manufactured by Modern Controls).
100). As shown in Table 1, this example shows an excellent oxygen barrier property of 1 cc or less, whereas Comparative Example 1 is inferior in the barrier property. Next, the film of Example 1 was placed in a vertical pillow-type bag making and filling machine, and the instant lamen were filled into small bags. The sample was left in a room at 40 ° C. and 90% RH for one month, opened, and tasted, but the taste and flavor of the instant ramen did not change. The film of Comparative Example 1 was also filled with instant ramen using a bag making and filling machine in the same manner as in the Example, left to stand under the same conditions, opened, and tasted. However, the ramen was oxidized and tasted. Was determined to be inferior. Similarly, the film of Example 1 was set in a gas-filled bag-filling machine, and green tea was filled in small bags. After leaving this sample in a room at 40 ° C. and 90% RH for 6 months, the sample was opened and tasted, but there was no change in the aroma and taste of green tea. The film of Comparative Example 1 was also filled with green tea using a gas-filled bag-making and filling machine in the same manner as in the example, opened after being allowed to stand under the same conditions, and tasted. Was. Comparative Example 1 had no change in taste and flavor in both instant lamen and green tea.
When these were incinerated, in Comparative Example 1 there was a problem that the Al metal remained unburned, whereas in this example, no particular problem occurred. In addition, the recycling of the base film in this example was easy.

[0015]

[Embodiment 2] A vapor deposition source having a size of about 3 to 5 mm was used.
Flaky Al_TwoO_Three(Purity 99.5%) and SiO_Two
(Purity: 99.9%), using electron beam evaporation method
μm thick PET film (Toyobo Co., Ltd .: E510
0) An aluminum oxide / silicon oxide based thin film is formed on
Was. The deposition conditions include the electron gun (EB gun)
The heating current was 1.5 A, the heating ratio was changed, and the composition was changed.
The thickness of the deposited film is 600, 2000A (Angstrom
And laminated with PE (polyethylene) 40μm
Thus, Examples 2 to 12 were produced. This packaging film
Or oxygen barrier properties after gelbo treatment
Specified. As a comparative example, 2-Al_TwoO_Three+ SiO_Two
Composition ratio (10:90), Al _TwoO_Three, SiO composition
Film into PET film by the same method as in the example.
Evaporated, further laminated with PE, Comparative Examples 2- ~
Produced. This packaging film or gelbo treatment
After the application, the oxygen barrier property was measured. The specific gravity of the membrane is
After dissolving the PET film, the measurement is performed by the floatation method.

Next, a method for testing bending fatigue resistance will be described. Test method for flex fatigue resistance (hereinafter referred to as gelbo property) The flex fatigue resistance was evaluated using a so-called gelbo flex tester (manufactured by Rigaku Corporation). The conditions are (MIL-B131H) 11.2 inches × 8 inches
The sample piece of the channel is cylindrical with a diameter of 3 (1/2) inch, the both ends are held, the initial holding interval is 7 inches, and the stroke is 3 (1/2) inch and a twist of 400 degrees is applied. Reciprocating motion 40 times / m
The test was conducted at a speed of 20 ° C. and a relative humidity of 65%.

In Comparative Examples 2 to 5, the oxygen barrier property was
In contrast to 5 cc or more, this embodiment shows good characteristics at 2.0 cc or less. Further, in the characteristics after molding, Comparative Example 2 was also inferior in large, whereas in this example, it was excellent at 2.5 cc or less even after molding. In the case of Examples 2-, ..., 10, 11 in which the specific gravity is within the specified range, the results are particularly excellent. In Comparative Examples 2- to, while the properties after the gelbo treatment were 7 cc or more,
This embodiment is excellent at 2.5 cc or less. When the specific gravity is within the specified range, it is particularly excellent at about 1 cc.

[0018] The film of Examples 2 to 12 was set on a bag making machine, and seaweed was packaged while being formed into a bag. After leaving this sample in a room at 40 ° C. and 90% RH for 3 months, the sample was opened and tasted, but the glue was not wet at all, and the taste and flavor did not change. The films of Comparative Examples 2 to 5 were formed by a bag making machine in the same manner as in the Examples, and the laver was packaged. After being left under the same conditions as in the example, the sample was opened and tasted. However, the seaweed was slightly damp, and the taste was judged to be inferior. Examples 2- to 12
The OPP film printed on the non-evaporated PET surface of this film was dry-laminated and heat-sealed to form a bag (20 × 30 cm).
It was created. After the bag was subjected to gelbo treatment (100 times), potato chips were packaged and the opening was heat-sealed to seal the bag. 25% of this sample, 65%
After being left in the RH room for 6 months, it was opened and tasted, but the color, taste, and dryness of the potato chips did not change. The films of Comparative Examples 1 to 6 were also formed into bags in the same manner as in Examples, wrapped with potato chips, and opened after being left under the same conditions.
After a taste test, the potato chips were slightly discolored, had an oxidizing odor, were slightly moist, and had a reduced crispy feeling.

[0019]

According to the present invention, in a dry food packaging material and a package using a gas barrier film in which an aluminum oxide / silicon oxide thin film is formed on a plastic substrate, the aluminum oxide in the thin film is from 20% by weight to 99%. % Or more of the gas barrier film, or 20 to 99% by weight of aluminum oxide in the thin film, and the specific gravity of the thin film and the content in the thin film. Is expressed by a relational expression of D = 0.01A + b (D: specific gravity of the thin film, A: weight% of aluminum oxide in the thin film), the specific gravity of the thin film is 1.6 ≦ b. By setting the gas barrier film within the range represented by ≦ 2.2 as a whole or a part of the configuration, the gas barrier film is excellent in gas barrier properties,
It is possible to provide a packaging material and a package for dried foods that are environmentally friendly and have excellent practical characteristics.

[0020]

[Table 1]

[0021]

[Table 2]

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshiyuki Otani 2-1-1 Katata, Otsu-shi, Shiga Prefecture Toyo Spinning Co., Ltd. (72) Inventor Yozo Yamada 2-1-1 Katata, Otsu-shi, Shiga Prefecture Examiner Hiroaki Hirai in the Research Laboratory of Toyobo Co., Ltd. (56) References JP-A-4-99165 (JP, A) JP-A-60-23037 (JP, A) JP-A-3-23934 (JP, A) ( 58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (2)

(57) [Claims] 1. A method according to claim 1, wherein at least one side of the plastic substrate has
A thin film having a composition mainly composed of aluminum oxide and silicon oxide is provided.
A dry food packaging material comprising 0 to 99% by weight and comprising, as a whole or a part, a gas barrier film having a specific gravity of the thin film satisfying the following formula. D = 0.01A + b, where D: specific gravity of the thin film, A: weight% of aluminum oxide in the thin film 1.6 ≦ b ≦ 2.2 2. A package for a dried food, comprising using the packaging material for a dried food according to claim 1.