JP3215933B2 - Pull tab - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid paper container such as a liquid or a powder, more specifically, sake, shochu, wine, whiskey, seasoning, juice, liquid detergent, hair setting solution, emulsion wax, bathing. The present invention relates to a pull-tab of a paper container used for sealing a spout portion of a paper container filled with an agent, antifreeze, or the like.

[0002]

2. Description of the Related Art In a conventional fluid paper container such as liquid or powder, a pull tab provided at an opening has an adhesive layer inside the container, a single heat-meltable resin film, and a pull tab provided outside the container has a sealed portion. Laminated films have been used which have a workability at the time, heat resistance, a barrier property against water vapor or oxygen gas that gives the suitability for preserving the contents, a strength giving easy opening, and the like. Laminated films including aluminum foil have been widely used as materials satisfying these conditions.

A portion provided outside the container of a pull tab (hereinafter, referred to as an outer tape), which is heat-sealed with a heat-meltable resin film (hereinafter, referred to as an inner tape) as an adhesive layer inside the container.
For the adhesive layer, the same type of polyethylene as the heat-fusible resin film of the inner tape was used. And this polyethylene film is a conventional film manufacturing method,
It was manufactured by an inflation method, a T-die method, or the like. The adhesive layer provided on the outer tape is coated with a material that can be heat-sealed with the inner tape on the aluminum foil surface, or
It was composed by laminating the film.

[0004]

In the conventional pull tab, since the adhesive layer in contact with the contents of the container is formed of a polyethylene resin, organic compounds such as fragrances, medicinal ingredients, alcohols and surfactants are used. Also, since alkaline components such as amines penetrate and pass through the adhesive layer and are blocked by the aluminum foil, they stay at the interface between the adhesive layer and the aluminum foil, softening or dissolving the adhesive layer of the outer tape to the outside. In some cases, the adhesive strength of the tape adhesive layer was reduced and peeling was caused. And when opening, only the pull tab is separated, leaving the inner tape and the adhesive layer in the opening of the container,
There was a problem of being peeled off.

According to the present invention, the pull tab of the paper container does not decrease the adhesive strength of the outer tape adhesive layer due to a content component filled with a fragrance, a medicinal component, an alcohol, a surfactant, an alkaline component and the like. Then, it is an object of the present invention to provide a pull tab which is removed in a state including the inner tape and the adhesive layer in the opening at the time of opening and is completely opened.

[0006]

In order to achieve the above object, a pull tab of the present invention is provided on a part of a container,
In the pull tab that seals the opening, the inner tape provided on the inner surface of the container is formed of a heat-meltable resin film, and the outer tape provided on the outer surface of the container is formed of an adhesive layer formed of the heat-meltable resin from the inner tape side. An adhesive resin comprising a copolymer with an unsaturated monomer containing a carboxyl group, and an aluminum foil are sequentially laminated, and the adhesive layer has a melting temperature containing the ethylene / carboxyl group. It is configured to be higher than the melting temperature of the copolymer with the unsaturated monomer, and the inner tape and the adhesive layer of the outer tape are heat-sealed. Further, the aluminum foil has a reinforcing film bonded to the surface opposite to the adhesive resin made of a copolymer with an unsaturated monomer containing an ethylene / carboxyl group via an adhesive layer. You may.

A copolymer with an unsaturated monomer containing an ethylene / carboxyl group is an ethylene / acrylic acid copolymer,
Ethylene / methacrylic acid copolymer, ethylene / acrylic acid / ethyl acrylate copolymer, or ethylene /
It is one of a methacrylic acid / ethyl acrylate copolymer, and the melting temperature of the adhesive layer is higher than the melting temperature of a copolymer with an unsaturated monomer containing an ethylene / carboxyl group. The adhesion between these copolymers and aluminum is subject to thermal history because the carboxyl groups are adsorbed on the metal surface and ionized and the two oxygen atoms of RCOO- coordinate with the surface metal to form chelates. In this case, the adhesive strength is increased, and chemically stable adhesive strength can be maintained.

The heat-fusible resin film used for the inner tape is made of heat-fusible plastic film.
It can be selected appropriately. For example, if the density is 0.91
A film made of a copolymer of ethylene and propylene, a film made of a copolymer of ethylene and propylene, a copolymer of ethylene with an α-olefin such as propylene, butene, pentene, octene and 4-methylpentene-1. There is a film made of a copolymer of ethylene and an unsaturated monomer having a carbonyl group such as vinyl acetate, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, and ethyl acrylate. These films may be coextruded multilayer films of two or more types. In this case, it is preferable to lower the melting temperature of the resin on the heat sealing portion side.

In order to easily tear the film of the inner tape, another resin, an organic filler,
An inorganic filler may be added.
5 to 60% by weight is suitable. The thickness of the inner tape is determined by the rigidity required for the workability at the time of sealing and the tearability at the time of opening. 20 to 200 μm, depending on the material
Is preferred.

The adhesive layer used for the outer tape needs to be heat-sealed with the inner tape, and is basically made of the same material as the heat-fusible resin film of the inner tape. However, the materials are not necessarily limited to the same material for the following reasons. That is, it is a necessary condition that the outer tape be removed from the container at the time of opening, and for that purpose, it is necessary to avoid using an additive for making the outer tape easy to tear like the inner tape.

The lamination of the aluminum foil and the adhesive layer resin is as follows:
A method in which an adhesive resin and an adhesive layer are simultaneously provided on the aluminum foil surface by co-extrusion coating, or an adhesive resin in the first unit and an adhesive layer resin in the second unit are provided on the same line by tandem extrusion coating. You can also. Further, the film of the adhesive layer produced in another step can be subjected to sandwich lamination by extrusion coating using an adhesive resin. The thickness of the adhesive layer of the outer tape is suitably 5 to 100 μm.

The adhesive resin between the aluminum foil and the adhesive layer according to the present invention is a copolymer of ethylene and a monomer containing a carboxyl group. And the monomer containing a carboxyl group is acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid and the like. It is necessary to select the minimum thickness of the adhesive layer of the outer tape that has a sufficient adhesive strength to cut the inner tape, and it is appropriately 5 to 50 μm depending on the material.

The aluminum foil used for the outer tape has a thickness of 5 to 50 μm, and it is preferable that the aluminum foil is annealed to remove oils and fats in order to stabilize the adhesion with the adhesive resin.
The heat-resistant base material is a biaxially stretched nylon film,
Axial stretched polyester film and paper are used. The lamination of the heat-resistant base material and the aluminum foil can be performed by extrusion coating with polyethylene in between, or sandwich lamination by co-extrusion coating, in addition to lamination by ordinary dry or wet lamination.

[0014]

According to the present invention, the melting temperature of the adhesive layer is higher than the melting temperature of the adhesive resin. Therefore, at the temperature at which the inner tape and the outer tape are heat-sealed, the copolymer of ethylene as the adhesive resin and the monomer containing a carboxyl group is subjected to a heat history higher than its melting temperature. It works to make the adhesive strength with the foil stronger. This is because the adhesion between aluminum and the adhesive layer is based on the fact that the carboxyl groups are adsorbed on the metal surface and ionized to RCOO.
This is because two oxygen atoms of-are coordinated with the surface metal so as to form a chelate, so that chemically stable adhesive strength can be maintained. Therefore, even if a fragrance, a medicinal component, an alcohol, a surfactant, an alkaline component, or the like contained in the contents of the container softens the adhesive resin, the adhesive strength is not reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, the container 1 shown in FIG. 1 is not shown in the drawing, but low-density polyethylene 30 μm / paper 340 g / m ² / low-density polyethylene 30 μm / anchor Coating material / biaxially oriented polyester film 12μm / adhesive / aluminum foil 9μm
/ 20 μm ethylene / methacrylic acid copolymer / 40 μm low density polyethylene. And
A govel top type paper container having a side of 75 mm is formed, and a pentagonal opening is provided as a spout. The outer tape is as shown in FIG.
Biaxially stretched polyester film 12 μm / adhesive / aluminum foil 30 μm / ethylene-methacrylic acid copolymer 20 μm (adhesive resin 5) / low-density polyethylene film 30 μm (adhesive layer 4) (melting temperature: 108 ° C.) Were laminated in the configuration described above. The laminate of the aluminum foil and the polyethylene film was formed by sandwich lamination by extrusion coating using an ethylene / methacrylic acid copolymer (melting temperature: 102 ° C.). Adhesion strength between aluminum foil and ethylene / methacrylic acid copolymer is 420g / 1
It was 5 mm wide. As the inner tape, a low-density polyethylene film of 100 μm (melting temperature: 108 ° C.) was used. At the opening of the paper container, the inner tape and the outer tape were heat-sealed at 170 ° C. for 2 seconds and 3 kg / cm ^{2 in} the shape shown in FIG. The adhesive strength between the aluminum foil and the ethylene / methacrylic acid copolymer was increased to 630 g / 15 mm width.

Comparative Example As a comparative example, as shown in FIG. 4, a biaxially stretched polyester film (which is a heat-resistant substrate 8) 12 μm / adhesive / aluminum foil 30 μm / anchor coating material / low density polyethylene 30 μm / low An outer tape of 30 μm in density polyethylene (melting temperature: 108 ° C.) was constructed. The difference from this embodiment of the laminate is that the adhesive layer 5a is formed by extrusion coating of polyethylene using a polyester-type polyurethane anchor coat material as an adhesive. The adhesive strength between the aluminum foil and the polyethylene was 500 g / 15 mm width. Further, the materials of the paper container and the inner tape were used in accordance with Example 1. At the opening of the paper container, the inner tape and the outer tape were heat-sealed at 170 ° C. for 2 seconds and 3 kg / cm ^{2 in} the shape shown in FIG. The adhesive strength between the aluminum foil and the low-density polyethylene was almost unchanged at 530 g / 15 mm width.

The paper containers of the above Examples and Comparative Examples were filled with a test solution having the following composition, stored at 50 ° C. for 30 days so that the opening was in contact with the contents, and opened with a pull tab. The state of the spout was observed. [Test liquid 1] Non-ionic surfactant 20 parts by weight Ethanolamine 30 parts by weight Sodium hydroxide 2 parts by weight Water 48 parts by weight [Test liquid 2] Ethanol 40 parts by weight Water 60 parts by weight [Test liquid 3] Magnesium sulfate 20 Parts by weight Limonene 2 parts by weight Synthetic alcohol 2 parts by weight Ethanol 12 parts by weight Water 64 parts by weight As a result, even in the case of any of the test liquids filled, the polyethylene film can be peeled off from the aluminum foil surface. And the contents could be poured out from the opening. On the contrary, in all of the comparative examples, the pull tab was removed from the aluminum foil surface at the opening while leaving the peeled polyethylene film, and the contents could not be poured out.

[0018]

As described above, the present invention is constructed as described above, so that fragrances, medicinal components, alcohols, surfactants, alkaline components and the like contained in the contents of the container penetrate and pass through the adhesive layer. Thus, even if the adhesive stays at the interface between the adhesive layer and the aluminum foil, the adhesive strength of the adhesive layer of the outer tape is reduced and the tape does not peel off. Therefore, when the pull tab is opened, the outer tape and the inner tape can be removed simultaneously, so that the opening can be made completely and easily.

[Brief description of the drawings]

FIG. 1 is a basic sectional view in which a paper container is heat-sealed with a pull tab of the present invention.

FIG. 2 is an enlarged conceptual diagram showing a configuration of a pull tab in FIG.

FIG. 3 is a cross-sectional view of an outer tape to which the heat-resistant base material of the present invention is bonded.
FIG .

FIG. 4 is a conceptual sectional view showing a configuration of an outer tape of a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Pull tab 3 Inner tape 34 Thermal bonding part 4 Adhesive layer 5 Adhesive resin 5a Adhesive resin in a comparative example 6 Aluminum foil 7 Outer tape 8 Heat resistance_base material 9 Adhesive layer 10 Anchor coat material

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B65D 53/04 B65D 53/00 B32B 15/08

Claims (3)

(57) [Claims] 1. A pull tab provided on a part of a container for sealing an opening, wherein an inner tape provided on an inner surface of the container is made of a heat-fusible resin film, and an outer tape provided on an outer surface of the container is an inner tape. from the side, the adhesive layer comprising a thermofusible resin is composed adhesive resin comprising a copolymer of an unsaturated monomer containing an ethylene / carboxyl group, an aluminum foil are laminated in this order, and the adhesive layer Is the melting temperature
The degree is an unsaturated monomer containing an ethylene / carboxyl group.
Is configured to be higher than the melting temperature of the copolymer with the body
The inner tape and the adhesive layer of the outer tape
A pull tab which is heat-sealed . 2. The method according to claim 1, wherein the aluminum foil is ethylene / calcium.
Contact consisting of a copolymer with an unsaturated monomer containing a boxyl group
Pull tab according to claim 1, characterized in that it is laminated a film of reinforced through an adhesive layer on the opposite surface of the wearing resin. 3. An ethylene / carboxyl group containing ethylene / carboxyl group.
Copolymer with saturated monomer is ethylene / acrylic acid copolymer
Coalescence, ethylene / methacrylic acid copolymer, ethylene / a
Crylic acid / ethyl acrylate copolymer or ethyl
Any of len / methacrylic acid / ethyl acrylate copolymer
The pull tab according to claim 1, wherein the pull tab is any one of the following.