JP2682315B2 - Inner seal material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner seal material for sealing the mouth of a container, and more particularly to an inner seal material for high frequency sealing.

[0002]

2. Description of the Related Art Generally, an inner seal material is provided at the mouth of a container for storing powdered or granular contents such as coffee, milk powder, seasonings, etc. in order to protect the contents from deterioration due to moisture or oxidation. It is used. This inner seal material is composed of a laminate of a reseal layer (reseal layer) whose main material is an elastic sheet such as cardboard and a membrane layer (seal layer) whose main material is an aluminum foil or other metal foil, and is a cap. When the cap is removed, the reseal layer and the membrane layer are separated from each other, the reseal layer remains inside the cap, and the membrane layer remains at the mouth of the container. When it is attached to the part, the reseal layer is a membrane layer (
This membrane layer may be removed), and serves to prevent re-invasion of moisture, oxygen, etc. into the inside of the container together with the cap.

Conventionally, an emulsion adhesive or the like has been used to bond the membrane layer to the container mouth. However, when the membrane layer is peeled from the container mouth and opened, paper mess may occur or it may be peeled off cleanly. Because there were problems such as difficulty,
In order to improve this, a high-frequency sealing method has been developed as a method of sealing the container mouth with a sealing thin film that can be quickly and easily adhered to the container mouth and can be peeled off cleanly later (for example, , JP-B-61-9181, 63-28019
No., Tokuhei 3-2754 etc.)

This high-frequency seal is one in which the metal layer contained in the inner seal material is placed in a magnetic field to cause the metal layer itself to generate heat, and this heat is utilized for sealing.

[0005]

However, when high-frequency sealing is performed using the conventional inner seal material, the peeling layer, which is the uppermost layer of the membrane layer, loses its peeling function due to heat generation, or the resealing layer. The lowermost layer, the layer to be adhered, is melted by heating and the peel strength is not stable.
There was a problem that good peelability could not be obtained stably.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide an inner seal material suitable for performing high-frequency sealing, which can obtain stable and good peeling property even when high-frequency heating is performed. Especially.

[0007]

In order to achieve the above object, the inner seal material of the present invention comprises a membrane layer having at least a moisture-proof material layer and a resealing layer having at least an elastic sheet layer, In an inner seal material in which a membrane layer and the resealing layer are releasably laminated, the uppermost layer of the membrane layer is a chlorinated polypropylene on a release layer made of a mixture of an acrylic resin and a chlorinated vinyl acetate resin. It has an adhesive layer made of resin
The lowermost layer of the resealing layer is a polypropylene resin layer.

[0008]

In the present invention as described above, since the peeling layer, which is the uppermost layer of the membrane layer, has heat resistance, it maintains a good peeling function even after high frequency heating, and is the lowermost layer of the resealing layer. Since the adherend layer is also made of a material having heat resistance, the layer does not dissolve even when high frequency heating is performed, stable peel strength is maintained, and stable and good peelability is obtained as a whole.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the inner seal material of the present invention.

A thermoplastic glass sealing material layer 13 is provided on the lower surface of the moisture-proof material layer 12 such as aluminum foil, and a printed pattern layer 11 is provided on the upper surface of the moisture-proof material layer 12 if necessary.
Furthermore, a release layer 9 made of a mixture of an acrylic resin and a chlorinated vinyl acetate resin, which has a low affinity for polypropylene resin and is transparent, and an adhesive layer 10 made of a chlorinated polypropylene resin are laminated on top of this. The entire laminated body constitutes the membrane layer 15.

A polypropylene resin layer 8 serving as an adherend layer is provided on the upper surfaces of the peeling layer 9 and the adhesive layer 10, and a coextrusion film layer 7 including a polyethylene layer 5 and a polypropylene layer 6 and a polyethylene layer. The elastic sheet layer 3 obtained by polymerizing the paperboard material 1 and the foamed polyethylene layer 2 is laminated via 4 and the whole laminated body constitutes the resealing layer 14.

With such a structure, the inner seal material of the present invention is formed so that the resealing layer 14 and the membrane layer 15 can be separated between the peeling layer 9 and the polypropylene resin layer 8.

Since a high-frequency seal is applied as the moisture-proof material used for the moisture-proof material layer 12, it is preferable to use a metal material that prevents the permeation of moisture and oxygen into the container, such as the above-mentioned aluminum foil. Besides, an aluminum foil reinforced with a synthetic resin, a synthetic resin film obtained by vapor deposition of aluminum, or the like is used.

Although the release layer 9 is made of a mixture of an acrylic resin and a chlorinated vinyl acetate resin, a silicone resin or the like may be added in an amount of about several percent. The mixing ratio of the acrylic resin and the chlorinated vinyl acetate resin is not particularly limited, but from the viewpoint of heat resistance and peelability, it is 7: 3 to.
It is preferably in the range of 9: 1.

<Experiment> The resins shown in Table 1 were examined as the resin used for the release layer having the above-mentioned structure. Each of the following resins was applied on an aluminum foil, and a polypropylene film was overlaid thereon and heat-sealed, and the sealing temperature was changed to determine the sealing temperature at which sufficient peelability was not obtained.

[0017]

[Table 1]

From the above results, it can be seen that the use of the acrylic / vinyl chloride according to the present invention causes a small decrease in peelability even when sealing is performed at a high temperature.

Further, when a similar experiment was conducted by replacing the polypropylene film of the above experiment with a polyethylene film, the polyethylene film was melted and fused with the resin of the release layer, and sufficient release property was not obtained. .

The adhesive layer 10 is made of a chlorinated polypropylene resin, but a graft-polymerized chlorinated polypropylene resin is particularly preferable, and an additive such as an antiblocking agent or a softening agent may be appropriately added.

In this embodiment, the paperboard material 1 and the polyethylene foam layer 2 are polymerized and used as the elastic sheet layer 3 constituting the resealing layer 14. However, an inner seal material is used for the mouth of the container. When attached, the membrane layer 15 should be pressed uniformly against the container mouth, and even if the membrane layer 15 is removed and a cap is capped, the resealing layer 14 can be completely adhered to the container mouth. Anything is acceptable as long as it is.

Further, in the constitution of the resealing layer 14, the coextrusion film layer 7 heat-melts the polypropylene resin layer 8 which is the adhered layer and the expanded polyethylene layer 2 of the elastic sheet layer 3 through the layer. It is for stabilizing the adhesion by wearing.

FIG. 2 is a sectional view showing a state in which the inner seal material is loaded in a cap and the cap is capped on the mouth of the container. In the figure, 16 is a cap, 17 is a container body, 18 is a rib projecting from the inside of the cap side, 21
Is the neck of the container, 20 is the thread on the outside of the container neck, and 19 is the thread on the inside of the cap side. When the cap 16 is attached to the container mouth, the elastic force of the elastic sheet layer 3 causes the inner sealing material in the cap 16 to contact the container mouth, and allows the inner sealing material to pass through the magnetic field by the high-frequency induction heating method. The glass sealing material layer 13 of the sealing material is completely bonded.

Next, when the cap 16 is removed, as shown in FIG. 3, peeling occurs between the polypropylene resin layer 8 and the peeling layer 9, the resealing layer 14 is built in the cap 16, and the membrane layer 15 is It remains at the mouth of the container.

According to the inner seal material of the present invention, even if high-frequency sealing is performed, the peeling function of the peeling layer is not lost, and the peeling strength becomes unstable due to the dissolution of the adherend layer. A stable and good peeling property can be obtained.

The membrane layer 15 may be removed from the container opening or may be left as it is in the container opening.
After the membrane layer 15 is removed, the cap 16 is again attached to the mouth of the container, so that the elasticity of the elastic sheet layer 3 can close the container opening.

Next, a method of manufacturing the inner seal material according to the present invention will be described. First, a web of aluminum foil is unwound from a roll of aluminum foil (moisture-proof material), and polyethylene is extruded on one surface of the web as a glass sealing material layer and laminated by a laminating method. Next, a printed pattern layer, a release layer made of a mixture of an acrylic resin and a chlorinated vinyl acetate resin, and an adhesive layer made of a chlorinated polypropylene resin are sequentially applied to the other surface of the aluminum foil by a gravure printing method. To form a membrane layer. On the other hand, extruded molten polypropylene in a film shape between the polypropylene / polyethylene co-extrusion film produced in advance and the membrane layer produced above,
Both are laminated (sand lamination). Molten polyethylene is extruded in the form of a film between the paperboard material / foamed polyethylene laminated in advance with wax and the above laminated body to laminate (sand laminate) both. Further, by punching the laminated body into a circular shape having a diameter corresponding to the inner diameter of the cap 16, an inner seal material as a final product can be obtained.

[0028]

As described in detail above, according to the inner seal material of the present invention, a good peeling function is maintained and stable peeling strength is maintained even when high frequency heating is performed, so that it is stable as a whole. It has an excellent effect that excellent peelability can be obtained.

Therefore, the inner seal material of the present invention has an effect that it is particularly suitable for high-frequency sealing.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an inner seal material of the present invention.

FIG. 2 is a cross-sectional view showing a state in which an inner seal material according to an embodiment of the present invention is loaded in a cap, and the cap is capped on the container mouth.

FIG. 3 is a cross-sectional view showing a state in which, when the cap is removed from the container body from the state shown in FIG. 2, the resealing layer remains in the cap and the membrane layer remains in the container mouth.

[Explanation of symbols]

 1 Paperboard Material 2 Foamed Polyethylene Layer 3 Elastic Sheet Layer 4, 5 Polyethylene Layer 6 Polypropylene Layer 7 Coextrusion Film Layer 8 Polypropylene Resin Layer 9 Release Layer 10 Adhesive Layer 11 Printed Picture Layer 12 Moisture-Proof Material Layer 13 Glass Seal Material Layer 14 Resealing layer 15 Membrane layer 16 Cap 17 Container body

Claims (1)

(57) [Claims] 1. An inner seal material comprising a membrane layer having at least a moisture-proof material layer and a resealing layer having at least an elastic sheet layer, wherein the membrane layer and the resealing layer are releasably laminated. The uppermost layer of the membrane layer has an adhesive layer made of a chlorinated polypropylene resin on a release layer made of a mixture of an acrylic resin and a chlorinated vinyl acetate resin, and the bottom layer of the resealing layer. Is a polypropylene resin layer, which is an inner seal material.