JP2015024842A - Double wall bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double wall bag having high light shielding property and having a low content of residual solvent.SOLUTION: The double wall bag is formed by overlapping two pair of overlapping films, in each of which an outside film 10 and an inside film 20 are overlapped to each other, to each other so that the inside films face each other, and heat-sealing the peripheral edge part. The outside film comprises a linear low-density polyethylene film 12 having a light shielding ink layer 11 formed in the outer surface side, and the inside film comprises a laminate film formed by laminating linear low-density polyethylene films 22 and 23 on both surfaces of a metallized nylon film 21.

Description

  The present invention relates to a double wall bag. In particular, the present invention relates to a double-walled bag with a spout that contains a liquid used in an inner bag of a bag-in-box.

  Containers for filling and sealing foods such as food ingredients, beverages, dairy products, alcoholic beverages, seasonings, and non-foods such as photographic processing agents, wax for floors, detergents, toiletries, etc. In general, a packaging form called a bag-in-box is used.

  The bag-in-box is composed of an inner bag in which a cap made of a cap and a spout is attached to a bag made of a plastic film, and a cardboard box for exteriorizing the inner bag. In some cases, the inner bag is a double-walled bag without bonding the outer film and the inner film to improve impact resistance.

  On the other hand, not only oxygen barrier properties but also light shielding properties have been required for packaging materials in order to prevent deterioration due to the oxidation of contents. For this reason, packaging bags having improved light shielding properties, such as providing a metal vapor deposition layer or printing ink with high light shielding properties on the entire surface, have come to be used.

  Even in a bag-in-box, an outer corrugated cardboard box cannot be expected to have a light-shielding property to prevent the contents from being deteriorated. For the inner bag of a bag-in-box, a metal vapor deposition layer is provided. A double film in which a polyethylene film is laminated on the aluminum vapor deposition layer side of a composite film in which a polyethylene film is provided on both sides of a nylon film with aluminum vapor deposition on one side. There was a double bag in which the composite film was placed inside and the surroundings were heat sealed (Patent Document 1).

  However, the metal vapor deposition layer has cracks or cracks in the vapor deposition film, so that sufficient light shielding properties cannot always be obtained. On the other hand, the light shielding by the ink layer has a problem such as odor because the solvent used in the ink remains in the packaging bag.

  Known documents are shown below.

Japanese Utility Model Publication No. 58-56184

  This invention is made | formed in view of the above situations, and makes it a subject to provide the double wall bag with high light-shielding property and few residual solvents.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in the invention of claim 1, two sets of overlapping films in which an outer film and an inner film are overlapped are overlapped with the inner films facing each other, and a peripheral portion. In the double-walled bag heat-sealed,
The outer film is composed of a linear low density polyethylene film provided with a light-shielding ink layer on the outer surface side, and the inner film is a laminated film in which linear low density polyethylene films are laminated on both sides of a metal-deposited nylon film. It is the double wall bag characterized by becoming.

  The double wall bag of the present invention has high light shielding properties and little residual solvent. Therefore, it is easy to deteriorate under the influence of light and is suitable for packaging of contents sensitive to smell. Moreover, if it is used as a back-in box in combination with an external cardboard box, it has impact resistance and is suitable for liquid packaging.

It is explanatory drawing which showed typically the layer structure of an example of the double wall bag of this invention in the cross section. It is explanatory drawing which showed typically an example of the double wall bag of this invention with the plane. It is explanatory drawing which showed typically the cross section of an example of the double wall bag of this invention.

Hereinafter, embodiments for carrying out the present invention will be described.
FIG. 1 is an explanatory view schematically showing in cross section the layer structure of an example of the double-wall bag of the present invention.

  As shown in the cross-sectional view of FIG. 1, the outer wall film 10 and the inner film 20 are overlapped in each layer structure of the double wall of the double wall bag 100 of this example. The outer film 10 is composed of a linear low-density polyethylene film 12 having a light-shielding ink layer 11 provided on the outer surface side that becomes the outside as a bag.

  The inner film 20 is made of a laminated film in which a linear low density polyethylene film 22 is laminated on the outer film 10 side of the metal-deposited nylon film 21 and a linear low density polyethylene film 23 is laminated on the inner surface side as a bag. Yes.

  FIG. 2 is an explanatory view schematically showing an example of the double wall bag of the present invention in a plan view. FIG. 3 is an explanatory view schematically showing a cross section of an example of the double wall bag of the present invention.

  And the double wall bag 100 of this example heat-seal | wraps the overlapping peripheral part by making two sets of the superimposition film which overlap | superposed the outer film 10 and the inner film 20 oppose the inner films 20, and FIG. Thus, the peripheral seal portion 1 is provided to form a double-walled bag.

  At this time, not only the opposing inner films 20 are heat-sealed, but also the outer film 10 and the inner film 20 are heat-sealed to form a bag.

  As shown in FIG. 3, the double wall bag 100 has a hole penetrating the outer film 10 and the inner film 20 of one of the overlapping films, and the spout 31 of the plug 30 is attached to this hole. The spout 31 is hollow and serves as a flow path for contents, and serves as a spout. The outer tip of the spout 31 is blocked by the cap 32.

  The ink used for the light-shielding ink layer 11 provided on the linear low-density polyethylene film 12 of the outer film 10 is preferably an inorganic pigment ink from the viewpoint of weather resistance. Depending on the content of the pigment, brown or green pigments can be used. However, in the case of the present invention, the pigment is stored in a cardboard box and cannot be seen from the outside. It is preferable to print using a printing ink using carbon black as a pigment, and to provide the light-shielding ink layer 11.

  The printing method for providing the light-shielding ink layer 11 is not particularly limited, and the light-shielding ink layer 11 can be provided by a known printing method such as gravure printing, flexographic printing, or silk screen printing.

  The linear low density polyethylene film 12 is preferably a single-sided corona-treated film, and a light-shielding ink layer 11 is provided on the corona-treated surface. Then, the non-treated surface is directed to the inner film 20 side, and heat sealing is performed simultaneously with the linear low density polyethylene film 22 of the inner film 20 and the bag making.

  As the metal vapor-deposited nylon film 21 of the inner film 20, a vapor-deposited film obtained by vapor-depositing metal on a biaxially stretched nylon film is used. A nylon film that has been subjected to double-sided corona treatment can be preferably used. Aluminum is generally used as the metal, but other metals may be used as long as the metallic luster is obtained without using aluminum. The metal-deposited nylon film 21 may be provided with a deposition anchor layer or a deposition film protective layer.

  For the linear low density polyethylene film 22 and the linear low density polyethylene film 23 laminated on both surfaces of the metal vapor-deposited nylon film 21, a single-sided corona-treated film is used, and the corona-treated surface is the metal vapor-deposited nylon film 21 side. Laminate. Although the laminating method is not particularly limited, it can be laminated by a dry laminating method using a two-component curable urethane adhesive.

  At this time, the vapor-deposited surface of the metal-deposited nylon film 21 is preferably laminated toward the outer linear low-density polyethylene film 22.

  The use of a linear low density polyethylene film for the outer film 10 and the inner film 20 has heat resistance and stiffness compared to low density polyethylene, and in particular, a linear low density synthesized using a single site catalyst. This is because a polyethylene film has few low-melting substances, has stable heat resistance, and is suitable with almost no odor component.

  Since the spout 31 of the spout 30 is fused to the front and back of the laminated film, linear low-density polyethylene and low-density polyethylene that can be heat-sealed can be preferably used. The cap can be made of a soft material such as an elastomer.

  The double wall bag of the present invention as described above has high light shielding properties and little residual solvent. Therefore, it is easy to deteriorate under the influence of light and is suitable for packaging of contents sensitive to smell. Moreover, if it is used as a back-in box in combination with an external cardboard box, it has impact resistance and is suitable for liquid packaging.

  Specific examples of the present invention will be described below.

<Example 1>
As the linear low density polyethylene film 12 for the outer film 10, a single-sided corona-treated linear low density polyethylene film having a thickness of 75 μm is prepared, and a gravure is used on the corona-treated surface using black ink with a pigment of carbon black. Printing was performed, and a light-shielding ink layer 11 having a coating amount of 6 g / m ² was provided on the entire surface of the linear low-density polyethylene film 12.

  As the metal vapor-deposited nylon film 21 for the inner film 20, a vapor-deposited film in which an aluminum vapor-deposited layer 50 nm was provided on one side of a biaxially-stretched nylon film 15 μm subjected to double-sided corona treatment was prepared.

  Moreover, as the linear low density polyethylene film 22 and the linear low density polyethylene film 23, single-sided corona-treated linear low density polyethylene films having thicknesses of 40 μm and 55 μm were prepared, respectively.

  The linear low density polyethylene film 22 having a thickness of 40 μm is disposed on the vapor deposition layer side of the metal-deposited nylon film 21, and the linear low density polyethylene film 23 having a thickness of 55 μm is disposed on the opposite side thereof. The surface side was laminated. The laminating method was performed by a dry laminating method using a two-component curable urethane adhesive. After lamination, aging was performed at 40 ° C. for 5 days.

  Using the outer film 10, the inner film 20, and the cap 30 formed separately as described above, the double wall bag of Example 1 was created by making bags as shown in FIGS. 2 and 3. .

  Below, the comparative example of this invention is demonstrated.

<Comparative Example 1>
A double wall bag of Comparative Example 1 was prepared in the same manner as in Example 1 except that the light-shielding ink layer 11 was not provided on the outer film 10.

<Comparative example 2>
Instead of the metal-deposited nylon film 21 of the inner film 20, a double-sided corona-treated biaxially-stretched nylon film 15 μm without a vapor-deposited layer is used, and a black ink black ink is used on one side of the biaxially-stretched nylon film. Comparative Example as in Example 1 except that gravure printing was performed, a light-shielding ink layer having a coating amount of 6 g / m ² was provided on the entire surface of one surface of the nylon film, and a linear low-density polyethylene film 22 was laminated. Two double wall bags were made.

<Comparative Example 3>
The light shielding ink layer 11 is not provided on the outer film 10, and gravure printing is performed on the vapor deposition layer side of the metal vapor-deposited nylon film 21 of the inner film 20 using black ink with a pigment of carbon black. A double wall bag of Comparative Example 3 was prepared in the same manner as in Example 1 except that a light-shielding ink layer having a coating amount of 6 g / m ² was provided and a linear low density polyethylene film 22 was laminated.

<Test method>
The double wall bags of the example and the comparative example were tested by the following method and comparatively evaluated.

<Light shielding>
Samples were cut out from the double-wall bags of Examples and Comparative Examples, and the light transmittance at a wavelength of 800 nm was measured in a state where the outer film 10 and the inner film 20 were overlapped, and the light shielding property was evaluated.

<Residual solvent>
Samples were cut into a size of 100 mm × 100 mm from the double-wall bags of the example and the comparative example, set in GC (product number 7890N) manufactured by Agilent, and the residual solvent was extracted at 80 ° C. for 20 minutes. Was measured.

以下に、実施例と比較例との比較結果について説明する。

Below, the comparison result of an Example and a comparative example is demonstrated.

<Comparison result>
The double wall bag of Example 1 had good light shielding properties, and the amount of residual solvent was also lower and better than Comparative Examples 2 and 3. On the other hand, since the double-wall bag of Comparative Example 1 was not provided with the light-shielding ink layer 11, the residual solvent was 0 mg / m ² , but the light-shielding property was lighter than that of the other Comparative Examples and Examples. It is an order of magnitude higher and it is judged that the deterioration of food by light cannot be prevented sufficiently.

  Further, the double wall bags of Comparative Example 2 and Comparative Example 2 had good light shielding properties, but the amount of residual solvent was larger than that of Example 1 and was suitable for packaging of odor sensitive contents. Not. In addition, when the double wall bags of these examples and comparative examples are filled with the liquid contents, put in the outer cardboard box, and used as a bag-in-box, there is no bag breakage or tearing, impact resistance The properties were equally good.

DESCRIPTION OF SYMBOLS 100 ... Double-wall bag 1 ... Perimeter seal part 10 ... Outer film 20 ... Inner film 11 ... Light-shielding ink layers 12, 22, 23 ... Linear low density polyethylene film 21 ... Metal-deposited nylon film 30 ... Mouth 31 ... Spout 32 ... Cap

Claims (1)

In the double-walled bag in which two sets of superposed films obtained by superimposing the outer film and the inner film are superposed with the inner films facing each other, and the peripheral part is heat-sealed,
The outer film is composed of a linear low density polyethylene film provided with a light-shielding ink layer on the outer surface side, and the inner film is a laminated film in which linear low density polyethylene films are laminated on both sides of a metal-deposited nylon film. A double-walled bag characterized by

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