JPH0769369A - Sealing film - Google Patents

Abstract

PURPOSE:To provide a sealing film which is fused to the opening part of a container by a high frequency induction heating process and is excellent in sealing and unsealing ability and which avoids the danger at the time of fusion by providing the sealing film with a minor diameter part and a major diameter part intersecting the minor diameter part perpendicularly. CONSTITUTION:A sealing film has at least a high frequency fusing layer formed on its aluminum foil layer and has a minor diameter part 2 and a major diameter part 3 intersecting the minor diameter part 2 perpendicularly. The center of a sealing film 1 is placed over the center of a circular opening part 11 of a container 10 with the center point of the film matching with that of the container opening part. At this time, both the end parts 2a and 2b of the minor diameter part 2 are made to extend from the edge part 12 of the container opening by 0.1-3mm. Both the end parts 3a and 3b of the major diameter part 3 are made to extend longer than the extended end parts 2a and 2b of the minor diameter part 2 by 2-5mm. The extending length of the peripheral film edge 4 is gradually decreased from the end parts 3a and 3b of the major diameter part 3 toward the end parts 2a and 2b of the minor diameter part 2. Therefore, the edge of the major diameter part becomes weaker in fusion than that of the minor diameter part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing film, and more particularly to a sealing film which is welded to a container opening by a high frequency induction heating method and is excellent in sealing property and unsealing property with respect to the container opening.

[0002]

2. Description of the Related Art Conventionally, as a sealing film for sealing a container opening by a high frequency induction heating method, a sealing film which is welded to the container opening and improves the unsealing property is used. There is a so-called picking tongue attached. When the sealing film with such a tongue attached is welded to the container opening by the high-frequency induction heating method, the outer peripheral portion of the sealing film becomes hot and the portion to be welded is compared to other welded portions. Then, since the temperature becomes low, there is a problem that the welding at the portion to be welded becomes incomplete. Therefore, in order to deal with such a problem, a plurality of score lines are made in the tongue piece so that the heat generated by the high frequency induction heating method is not collected in the outer peripheral portion of the tongue piece (Actually, Sho 60). -27053).

However, in the seal lid described in Japanese Utility Model Laid-Open No. 60-27053, the metal of the cut line portion of the tongue piece is exposed when it is welded to the container opening by the high frequency induction heating method. However, there is a risk that sparks may be generated from the cut line portion, and the welding stability of the seal lid, that is, the sealing performance is poor. Further, the seal lid as described above has a high sealing property when it is welded by using a strong high frequency, but has a defect that the unsealing property is poor, and when a strong high frequency is used, the contents of the container are May be adversely affected.

Therefore, an object of the present invention is to provide a sealing film which is welded to a container opening by a high frequency induction heating method, has excellent sealing property and openability, and is free from danger at the time of welding.

[0005]

According to the present invention, at least a high-frequency welding layer is laminated on an aluminum foil layer, and the high-frequency welding layer is provided in the circular opening of a container having a circular opening which is substantially a perfect circle. In a sealing film that is welded by a high frequency induction heating method to seal the circular opening, the sealing film has a short diameter portion and a long diameter portion orthogonal to the short diameter portion, and the sealing film is the center point thereof. Is placed on the circular opening in conformity with the center point of the circular opening of the container to be sealed, both ends of the short-diameter portion are 0 from the opening edge of the circular opening. 0.1 to 3 mm, and at least one end of the long diameter part further projects 2 to 5 mm from the projection length of both ends of the short diameter part,
The projecting length of the film peripheral edge portion from one end of the long diameter portion to both ends of the short diameter portion is gradually reduced from one end of the long diameter portion to both ends of the short diameter portion. Sealing film characterized by the above (first invention)
The above object is achieved by providing

Further, according to the present invention, at least a high frequency welding layer is laminated on an aluminum foil layer, and the high frequency welding layer is provided in the circular opening of a container having a circular opening such as an ellipse or an oval. In the sealing film which is welded by a high frequency induction heating method to seal the circular opening, the sealing film has a short diameter portion passing through the center point and a long diameter portion orthogonal to the short diameter portion, When the point is placed on the circular-shaped opening by aligning the central point of the circular-shaped opening of the container to be sealed and aligning the long-diameter portion with the long-diameter opening of the circular-like opening, Both ends of the short diameter part are 0.1 to 3 mm from the opening edge of the circular opening.
While projecting, and at least one end of the long diameter portion further projects 2 to 5 mm from the projection length of both ends of the short diameter portion, and a film peripheral edge portion extending from one end of the long diameter portion to both ends of the short diameter portion. By providing a sealing film (second invention), the protruding length of which is gradually reduced from one end of the long diameter portion to both ends of the short diameter portion. It has been achieved.

[0007]

When the sealing film of the present invention is welded to the container opening by the high frequency induction heating method, the projecting length of the peripheral edge of the film is gradually reduced from one end of the long diameter portion to both ends of the short diameter portion. From the edge of the long diameter portion of the container opening, the welding becomes weaker than the edge of the short diameter portion,
In addition, the welding gradually decreases from one end of the long diameter portion to both ends of the short diameter portion. Therefore, if the long diameter portion is pinched and opened, the opening can be smoothly performed.

In the sealing film of the present invention, both ends of the short diameter portion may be projected by 0.1 to 3 mm from the opening edge of the circular opening of the container to be sealed, preferably by 1 to 2 mm. ing. If the protruding length of each of the both ends of the short-diameter portion is less than 0.1 mm, heat due to the high frequency induction heating method is applied too strongly to the opening edge portion of the container, which may dissolve contents such as hand cream,
Further, if it exceeds 3 mm, the influence of heat applied to the peripheral portion of the film is small, the heating between the container opening and the high frequency welding layer becomes insufficient, and the high frequency output must be increased unnecessarily in order to enhance the heating and the welding. I won't. In addition, in the sealing film of the present invention, at least one end of the long diameter portion may further project by 2 to 5 mm from the projecting length of both ends of the short diameter portion, and preferably 3 to 4 mm. If the difference in the protruding length of at least one end of the long diameter portion is less than 2 mm, the strength of welding of the edges of the short diameter portion and the long diameter portion becomes small, and smooth opening properties cannot be obtained.
If it exceeds mm, the welding temperature difference at the edges is too large, the welding at the edges of the long diameter portion becomes insufficient, or the contents near the edges of the short diameter portion are melted.

The projecting length of each of the short diameter portion and the long diameter portion of the sealing film is appropriately changed according to the size of the opening portion (can diameter) of the container to be sealed, and the opening portion (can diameter) of the container is changed.
It is preferable that the larger the protrusion length is within the above range, the larger the protrusion length is. For example, when the can diameter is 108 mm, the protrusion length of each of the both ends of the minor diameter portion is 1.5 m.
m, the difference in the protruding length of at least one end of the long diameter part is 4 mm
When the can diameter is 78 mm, it is preferable that the protruding lengths of both end portions of the short diameter portion are 1 mm and the difference between the protruding lengths of at least one end portion of the long diameter portion is 3.5 mm.

[0010]

Embodiments of the sealing film of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a main part of a first embodiment (embodiment of the first invention) of a sealing film of the present invention, and FIG. 2 is welded to a circular opening of a container by using the sealing film of the present invention. It is a perspective view which shows the external appearance of the sealed container.

<Example 1> Sealing film 1 of the present example
Is a lamination of at least a high frequency welding layer on an aluminum foil layer, and as shown in FIG. 2, the circular opening 1 of the container 10 having a circular opening (can diameter 108 mm) 11 which is substantially a perfect circle.
1 is welded by a high frequency induction heating method through the high frequency welding layer to seal the circular opening 11. These points are similar to the conventional sealing film.

Thus, as shown in FIG. 1, the sealing film 1 of this embodiment has a short diameter portion 2 and a long diameter portion 3 orthogonal to the short diameter portion 2, and the sealing film 1 has its center point at the center point. When the container 10 to be sealed is placed on the circular opening 11 so as to be aligned with the center point of the circular opening 11, both ends 2a and 2b of the minor diameter portion 2 are respectively the circular openings. 1
1.5 mm projecting from the opening edge portion 12 of 1 and both ends 3a and 3b of the long diameter part 3 further projecting 4 mm from the projecting lengths of the both ends 2a and 2b of the short diameter part 2, and the long diameter part. 3 from the both end portions 3a and 3b to the both end portions 2a and 2b of the short diameter portion 2 respectively, the protruding lengths of the film peripheral edge portions 4 and 4 are the both end portions 3a of the long diameter portion 3,
It has a shape that gradually decreases from 3b toward the both ends 2a, 2b of the short diameter portion 2.

The sealing film of this embodiment will be further described. The sealing film 1 has a bilaterally symmetrical shape with the minor axis portion 2 as the axis of symmetry, and the aluminum foil layer is Formed from aluminum foil with a thickness of 30 μm,
The high frequency welding layer is formed of a polyester hot melt having a thickness of 20 μm. The aluminum foil layer and the polyester hot melt are laminated by an extrusion laminating method.

<Embodiment 2> FIG. 3 is a plan view showing a main part of a second embodiment (embodiment of the first invention) of the sealing film of the present invention. As shown in FIG. 3, in the sealing film 1'of this embodiment, one end portion 3c of the long diameter portion 3'is further protruded by 4 mm from both end portions 2c and 2d of the short diameter portion 2'and the above long diameter portion is formed. The protruding length of the other end portion 3d of 3'is the same as the protruding length of each of the both end portions 2c, 2d of the short diameter portion 2 ', and the other end portion 3d to the short diameter portion 2' The film has the same shape as that of the first embodiment except that the film peripheral edge portions 4 ′ extending over both ends 2 c and 2 d have the same protruding length.

<Embodiment 3> FIG. 4 is a plan view showing the essential parts of a third embodiment (embodiment of the second invention) of the sealing film of the present invention. The sealing film 21 of the present embodiment is formed by laminating at least a high-frequency welding layer on an aluminum foil layer, and the container 30 having an elliptical opening (long diameter 94 mm, short diameter 80 mm) 31 has the above elliptical opening 31 with The circular opening is sealed by a high frequency induction heating method through a high frequency welding layer.

Thus, the sealing film 21 of this embodiment is
As shown in FIG. 4, a short diameter portion 22 passing through the center point of the sealing film 21 and a long diameter portion 23 orthogonal to the short diameter portion 22 are provided.
The center point is aligned with the center point of the elliptical opening 31 of the container 30 to be sealed, and the long diameter portion 23 is aligned with the long diameter opening of the elliptical opening 31. When mounted on the short-diameter portion 22, both end portions 22a and 22b of the short-diameter portion 22 protrude 1 mm from the opening edge portion 32 of the elliptical opening portion 31, and both end portions 23a and 23b of the long-diameter portion 23 have the short-diameter portion. Both ends 22 of the portion 22
3.5 mm more than the protruding length of a, 22b, and the projection of the film peripheral edge portions 24, 24 extending from the both end portions 23a, 23b of the long diameter portion 23 to the both end portions 22a, 22b of the short diameter portion 22, respectively. Length is the long diameter part 2
3 has a shape that gradually decreases from the both end portions 23a, 23b of No. 3 toward the both end portions 22a, 22b of the short diameter portion 22, respectively.

The sealing film of this embodiment will be further described. In the sealing film 21, the aluminum foil layer is made of an aluminum foil having a thickness of 30 μm, and the high frequency welding layer is a polyester hot melt having a thickness of 20 μm. Has been formed. The aluminum foil layer and the polyester hot melt are laminated by an extrusion laminating method.

<Embodiment 4> FIG. 5 is a plan view showing an essential part of a fourth embodiment (embodiment of the second invention) of the sealing film of the present invention. In the sealing film 21 'of this embodiment, as shown in FIG. 5, one end 23c of the major diameter portion 23' has a minor diameter portion 22 '.
4 mm further than the projecting length of both end portions 22c and 22d of the above, and the projecting length of the other end portion 23d of the above long diameter portion 23 ′ is the same as the above both end portions 22c and 22d of the above short diameter portion 22 ′.
d has the same protrusion length as each other, and has the other end 2
3d to both ends 22c, 22d of the short diameter portion 22 '.
The shape is the same as that of the third embodiment except that the protruding lengths of the film peripheral edge portion 24 ′ are the same.

The circular opening to which the sealing film of the present invention (second invention) can be welded by the high frequency induction heating method through the high frequency welding layer is not limited to the elliptical opening, but is an oval or the like. It may be a circular opening.

The present invention is not limited to the above-mentioned embodiment, and the gradual reduction rate of the projecting length of the film peripheral edge portion from both ends of the long diameter portion to both ends of the short diameter portion can be appropriately selected. . Further, the sealing film of the present invention is not limited to the aluminum foil layer and the high-frequency welding layer forming the sealing film, and as the aluminum foil layer and the high-frequency welding layer, those forming a normal sealing film may be used. However, a sealing film having the following structure is particularly preferable.

The thickness of the aluminum foil layer of the sealing film of the present invention is preferably 6 to 50 μm, more preferably 12 to 40 μm, most preferably 20 to 30 μm. The thickness of the high frequency welding layer is preferably 5 to 40 μm, more preferably 7 to 30 μm, and most preferably 10 to 20 μm.

The high frequency welding layer is preferably composed of a polyester hot melt, and the preferable composition of the polyester hot melt includes the following compositions. In addition, the numerical value in () shows especially preferable composition. Dicarboxylic acid component; terephthalic acid 15-25 wt%
(21-23 wt%), isophthalic acid 10-15 wt% (10-14 wt%)
%), Adipic acid 10 to 25 wt% (14 to 19 wt%), diol component; 1,4 butanediol 50 wt%.

The physical properties of the polyester hot melt having the above composition are as follows. In addition, the numerical value in () is
It is a numerical value corresponding to a particularly preferable composition. Glass transition point -40 to -10 ° C (-40 to -15
℃), melting point 78-130 ℃ (80-110
℃), softening point 105-140 ℃ (110-131
° C).

Further, as the sealing film of the present invention, in the above-mentioned preferable sealing film, a polyethylene terephthalate layer (hereinafter referred to as a PET layer) is provided between the aluminum foil layer and the high frequency welding layer (polyester hot melt layer). It is more preferable to interpose. And P
When the ET layer is interposed, the thickness of the aluminum foil layer is preferably 7 to 40 µm, more preferably 9 to 40 µm.
It is 20 μm, most preferably 12 to 15 μm. The thickness of the PET layer is preferably 5 to 40 μm, more preferably 9 to 20 μm, and most preferably 1
2 μm. The thickness of the polyester hot melt layer is preferably 5 to 40 μm, more preferably 10 to 30 μm, and most preferably 20 μm.

[0025]

EFFECTS OF THE INVENTION The sealing film of the present invention is welded to the opening of a container by a high frequency induction heating method, has excellent sealing property and opening property, and there is no danger at the time of welding.

[Brief description of drawings]

FIG. 1 is a plan view showing a main part of a first embodiment (embodiment of the first invention) of a sealing film of the present invention.

FIG. 2 is a perspective view showing an outer appearance of a container which is welded and sealed in a circular opening of the container using the sealing film of the present invention.

FIG. 3 is a plan view showing a main part of a second embodiment (embodiment of the first invention) of the sealing film of the present invention.

FIG. 4 is a plan view showing a main part of a third embodiment (embodiment of the second invention) of the sealing film of the present invention.

FIG. 5 is a plan view showing a main part of a fourth embodiment (embodiment of the second invention) of the sealing film of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing film 2 Short diameter part 2a End part 2b End part 3 Long diameter part 3a End part 3b End part 4 Peripheral part 10 Container 11 Opening part 12 Opening edge part

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[Procedure amendment]

[Submission date] December 9, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

The high frequency welding layer is preferably composed of a polyester hot melt, and the preferable composition of the polyester hot melt includes the following compositions. In addition, the numerical value in () shows especially preferable composition. Dicarboxylic acid component; terephthalic acid 15 to 25% (21
~ 2%), isophthalic acid 10 to 1 5% (10 to 1 4%), 10 to 2 5% adipic acid (14-1 9%), the diol component; 1,4-butanediol 50%.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

Of the polyester hot melt having the above composition
The physical property values are as follows. In addition, the numerical value in () is
It is a numerical value corresponding to a particularly preferable composition. Glass transition point -40 to -10 ° C (-40 to -15
℃, melting point 78-130 ℃ (80-120
℃), softening point 105-140 ℃ (110-131
° C).

Claims (6)

[Claims] 1. A container formed by laminating at least a high-frequency welding layer on an aluminum foil layer and having a circular opening which is a substantially perfect circle in the circular opening through the high-frequency welding layer by a high-frequency induction heating method. A sealing film that is welded to seal the circular opening, wherein the sealing film has a short diameter portion and a long diameter portion orthogonal to the short diameter portion, and the container is intended to seal the center point of the sealing film. When placed on the circular opening in conformity with the center point of the circular opening, both ends of the short diameter portion are each 0.1 to 3 m from the opening edge of the circular opening.
m, and at least one end of the long diameter part further projects by 2 to 5 mm from the projection length of both ends of the short diameter part, and a film peripheral edge extending from one end of the long diameter part to both ends of the short diameter part. A sealing film having a shape in which a protruding length of the portion gradually decreases from one end of the long diameter portion toward both ends of the short diameter portion. 2. The sealing film according to claim 1, wherein the sealing film has a bilaterally symmetrical shape with the minor axis portion as a symmetry axis. 3. The projecting length of the other end of the long diameter portion is the same as the projecting length of both end portions of the short diameter portion, and extends from the other end portion to both end portions of the short diameter portion. The sealing film according to claim 1, wherein the protruding lengths of the film peripheral portion are the same. 4. A high-frequency induction layer is formed by laminating at least a high-frequency welding layer on an aluminum foil layer and having a circular-shaped opening such as an ellipse or an oval in the circular-shaped opening through the high-frequency welding layer. A sealing film which is welded by a heating method to seal the circular opening, wherein the sealing film has a short diameter portion passing through a center point and a long diameter portion orthogonal to the short diameter portion, and the center point is sealed. The minor diameter portion is placed on the circular shaped opening portion in alignment with the center point of the circular shaped opening portion of the container and the long diameter portion is aligned with the long diameter opening portion of the circular shaped opening portion. Both ends of the circular opening are 0.
It extends from 1 to 3 mm, and at least one end of the long diameter portion further projects from the length of both ends of the short diameter portion by 2 to 5 mm, and extends from one end of the long diameter portion to both ends of the short diameter portion. A sealing film having a shape in which a projecting length of a peripheral portion of the film is gradually reduced from one end of the long diameter portion to both ends of the short diameter portion. 5. The sealing film according to claim 4, wherein the sealing film has a left-right symmetrical shape with the minor axis portion as an axis of symmetry. 6. The projecting length of the other end of the long diameter portion is the same as the projecting length of both end portions of the short diameter portion, and extends from the other end portion to both end portions of the short diameter portion. The sealing film according to claim 4, wherein the protrusion lengths of the peripheral portions of the film are the same.