JP2009184717A - Lid member for packaging container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet-shaped lid member for a cup-shaped container wherein the shape-retainability is ensured without having an aluminum layer by a method being different from conventionally known ones. <P>SOLUTION: This sheet-shaped lid member has a tab 21 for opening on the outer peripheral edge, and is peelably fixed on the outer peripheral edge of an opening of the cup-shaped container body 10. The sheet-shaped lid member is formed of a laminate including at least a seal layer for the fixation on the outer peripheral edge of the operning, a polylactic acid-based film layer, and a base material layer made of a paper layer and a film layer. In the base material layer, a plurality of half-cuts 50a and 50b are made, and the lid member is constituted in such a manner that the lid member has a strength reduced in a region where the half-cuts are made. The polylactic acid base film layer has shape-retainability by itself, and by the synergistic effect between the shape-retainability and the half-cuts, the shape-retainability on opening and closing can be achieved without the aluminum layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sheet-like lid material used for packaging containers such as cup ramen and other instant foods.

  For example, as shown in FIG. 1, it is preferable that the sheet-like lid member 20 used for a cup ramen container can maintain an open state well while pouring hot water. For this reason, usually, the shape retention is improved by forming the lid member 20 as a laminated structure including a paper layer, an adhesive layer, an aluminum layer, and a heat-sealable plastic layer. That is, by including an aluminum layer in the laminated structure, the aluminum layer retains the flatness of the individual cover members 20 stacked in the manufacturing plant at the time of production. When pouring hot water into the body, the curved unsealed state of the partially opened lid member 20 is maintained.

However, when the lid 20 includes an aluminum layer, there are the following disadvantages.
(1) It becomes impossible to perform a foreign matter contamination inspection using a metal detector for a cup ramen as a final product. This is because the aluminum layer reacts to the metal detector.
(2) During waste incineration, aluminum remains in the incinerator and adheres to the inner wall of the incinerator.
(3) When cooking by a microwave oven is performed, sparks may occur at the outer periphery of the aluminum layer.

  In order to solve such a problem, it is necessary to omit the aluminum layer in the laminated structure of the lid material. From this point of view, the applicant of the present application has already developed a cover material that ensures shape retention while omitting the aluminum layer, and has applied for a patent (Patent Documents 1 and 2).

In Patent Documents 1 and 2, the aluminum layer is omitted from the laminated structure of the sheet-like lid material, and a plastic substrate layer is provided. And the easily-curved belt | band | zone area | region is provided in the opening direction substantially intermediate part of the sheet-like cover material.
This easily curved belt-like region is composed of a plurality of parallel half cuts penetrating the plastic substrate layer, thereby ensuring good shape retention.

JP 2002-104513 A JP 2003-095336 A

  An object of the present invention is to provide a lid member that has a shape retaining property without having an aluminum layer, by a method different from the above-described conventional technique.

Means for Solving the Problems and Effects of the Invention

According to the present invention, a sheet-like lid member having the following characteristics is provided.
The sheet-like lid material of the present invention has an opening tab on the outer peripheral edge, and is fixed to the outer peripheral edge of the cup-shaped container body so as to be peeled off. The sheet-like lid member is composed of a laminate including at least a “seal layer for fixing to the outer periphery of the opening”, a “polylactic acid film layer”, and a “base layer composed of a paper layer and a film layer”.
Furthermore, a plurality of half cuts are provided in the base material layer, and the lid material strength in the area where the half cuts are provided is reduced.

In the sheet-like lid material of the present invention having the above-described configuration, shape retention is realized using “half cut” and “polylactic acid film layer (PLA layer)”.
The polylactic acid-based film layer (PLA layer) is a plant-derived resin collected from corn or the like, and itself has shape retention. By adopting a PLA layer having such shape retaining properties and using a half cut in combination, effective shape retaining properties are realized while omitting the aluminum layer. In the area where the half-cut is formed, the lid material strength is relatively lower than in other areas. Therefore, using this area, the sheet-like lid material can be `` curved upward and opened ''. Can be maintained. That is, shape retention can be realized while omitting the aluminum layer.

  The polylactic acid film layer only needs to be present at an arbitrary position in the laminated structure, but when placed on the uppermost layer (upper surface), the uppermost polylactic acid layer contributes to shape retention, It is considered that the shape retaining property of the sheet-like lid material is most enhanced by the lower layer acting so as to follow it.

  Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The sheet-like lid material 20 of the present invention has a tab 21 for opening on the outer peripheral edge and is fixed to the outer peripheral edge 11 of the cup-like container 10 so as to be peeled off. In this respect, as shown in FIG. This is the same as the conventional example.

<< First Embodiment >>
FIG. 2 is a perspective view showing the cup-shaped container 10 provided with the sheet-like lid member 20 of the present invention, and FIG. 4 shows a cross section taken along line 4-4 in FIG. In the present invention, shape retention without an aluminum layer is realized by using a polylactic acid film layer (PLA layer) and a half cut.

The polylactic acid-based film layer (PLA layer) is a plant-derived resin collected from corn or the like, and itself has shape retention. Therefore, a certain degree of shape retention can be obtained even without an aluminum layer. In the present invention, in addition to this, an effective shape retention is realized by using a half cut in combination. Furthermore, when considering disposal, the PLA layer is a natural component, so it is superior in environmental problems as compared with the aluminum layer.
In the area where the half-cut is formed, the lid material strength is relatively lower than in other areas, so this area is used to make the sheet-like lid material `` curved upward and opened '' Can be maintained.

In the example shown in FIG. 2, half-cut groups 50 a and 50 b are formed in two regions on the sheet-like lid member 20. The half cut group 50a is composed of four half cuts, and the interval between them is relatively small. On the other hand, the half cut group 50b is composed of five half cuts, and the interval between them is relatively large.
As can be seen from the unsealed state shown in FIG. 3, in the region corresponding to the half-cut group 50a, the sheet-like lid material curves in a relatively small arc. Therefore, in the half cut group 50a, the interval between the half cuts is reduced.
On the other hand, in the region corresponding to the half-cut group 50b, the sheet-like lid material curves in a relatively large arc. Accordingly, in the half cut group 50b, the interval between the half cuts is increased.

However, the number and arrangement of the half-cut groups as described above, and the number and interval of the half-cuts included therein are not limited to those illustrated, and can be set as appropriate. However, from the viewpoint of ease of pouring hot water and high shape retention, it is preferable to provide a half cut at least at the position of the half cut group 50a in FIG.
In the example of FIG. 2, the half-cut group 50 a is at a position opposite to the opening tab 21 with respect to the center C of the lid, and is substantially orthogonal to the virtual line connecting the opening tab 21 and the lid center C. (I.e., extending substantially orthogonal to the opening direction indicated by arrow A). Alternatively, the half cut group may extend substantially orthogonal to the imaginary line at a position passing through the center C of the sheet-like lid member.

As a result, a large spout is secured, and the weight ratio of the lid member positioned on the opening tab 21 side is larger than that of the half-cut group 50a, and the shape retaining property at the time of opening and closing is affected by gravity. Rise.
That is, in the opened state shown in FIG. 3, the ratio of the lid part that curves upward and warps increases, and a favorable open state can be maintained under the influence of gravity. Moreover, even when steaming men, it is easy to maintain a closed state by the action of gravity.

≪Laminated structure of sheet-like lid material≫
As shown in the cross-sectional view of FIG. 4, the sheet-like lid member 20 includes, in order from the front side, “PLA layer”, “paper layer”, “PET (polyethylene terephthalate) substrate layer”, “PE (polyethylene) layer”. And “seal layer”.
The half cut group 50a is formed from the “PET base material layer” to the middle of the “paper layer”. And after forming the half cut 50a, a "PE layer" and a "seal layer" are laminated so that this may be covered. Although not shown, the half cut group 50b is the same.

  The “PLA layer” only needs to be present at an arbitrary position in the laminated structure. However, as shown in FIG. 4, when placed on the uppermost layer (upper surface), the shape retaining material of the sheet-like lid 20 is retained. It is considered that the sex is the highest. This is because the uppermost polylactic acid layer contributes to shape retention and the lower layers act to follow it.

≪Modification (Fig. 5) ≫
When putting the half cut on the back side of the sheet-like lid member, it is preferable to cover (close) the half cut with the lowermost heat seal layer as shown in the cross-sectional view of FIG. The reason is oil spot countermeasures. In other words, when the half-cut is exposed on the back side, especially in the case of contents containing oil, the oil will enter the exposed half-cut, and this will be visually recognized as a stain from the front side, reducing the commercial value. Because it does.

However, if there are film layers on both the front and back sides of the paper layer as shown in FIG. 4, bubbling problems may occur.
That is, when the sheet-like lid member is heat-sealed by the seal head, the moisture contained in the paper layer in the sheet-like lid member evaporates and tends to escape. At this time, if the film layers are laminated on both the front and back sides of the paper layer, the water vapor pushes up the film layer, causing a so-called bubbling phenomenon, and unevenness is generated on the surface of the sheet-like lid.

  In the modification shown in FIG. 5, in order to solve such problems of bubbling and oil spots, the half cut group 50a 'is inserted from the upper surface side of the sheet-like lid member 20'. Since the half cut is not exposed on the back side of the sheet-like lid member 20 ', oil spots can be effectively prevented. In addition, the moisture in the paper layer can escape from the half-cut group 50a 'to reduce the bubbling problem.

≪Paper layer in laminated structure≫
As the paper layer, those having at least a white surface and suitable for multicolor printing are preferred, and both art paper, piece art paper having a basis weight of about 50 g / m @ 2 to about 120 g / m @ 2, preferably about 75 g / m @ 2 to 100 g / m @ 2 or Double-sided or single-sided coated paper can be suitably used. If the paper layer is too thin, the paper layer itself may be torn at the time of peeling, or if a colored light-shielding layer is provided, for example, it may appear dark from the surface, resulting in poor commercial value. There is a risk that the dead hold property will be poor. Moreover, in addition to the paper layer, polyethylene terephthalate, stretched nylon, stretched polypropylene, polyethylene terephthalate obtained by ceramic vapor deposition of metal oxides such as aluminum oxide and silicon oxide, and the strength and various barrier properties of stretched polypropylene, etc. are excellent. A resin film can also be laminated.

≪Sealing layer in laminated structure≫
Examples of the sealing layer include polyolefin resins such as linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), high-density polyethylene (HDPE), and unstretched polypropylene (CPP) that are excellent in heat sealability, or ethylene / vinyl acetate. Films of ethylene copolymer resins such as copolymers (EVA), ethylene / acrylic acid copolymers (EAA), ethylene / methacrylic acid copolymers (EMAA) are preferably used, and polystyrene and polybutadiene are used as these polyolefin resins. It is also possible to mix an incompatible component with a polyolefin resin. Further, a hot melt adhesive made of ethylene / vinyl acetate copolymer resin, ethylene / acrylic acid copolymer resin or the like may be provided at a coating amount of about 15 to 25 g / m @ 2, and the container body (10 ) Can be sufficiently sealed with the flange portion (12) and can be peeled open.

The perspective view explaining the conventional cup container. The perspective view which shows the cup-shaped container provided with the sheet-like lid | cover material which concerns on 1st Embodiment of this invention. The perspective view which shows the opening state of the cup-shaped container of FIG. 4-4 sectional drawing in FIG. The figure explaining a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cup-shaped container 11 Opening outer periphery 20, 20 'Sheet-like lid | cover material 21 Opening tab 50a, 50b, 50a' Half cut group

Claims (4)

A sheet-like lid member having a tab (21) for opening on the outer peripheral edge and detachably fixed to the outer peripheral edge (11) of the cup-shaped container body (10),
The sheet-like cover material is composed of a laminate including at least a sealing layer for fixing to the outer periphery of the opening (11), a polylactic acid film layer, and a base material layer composed of a paper layer and a film layer,
A sheet-like lid material, wherein a plurality of half-cuts (50a, 50b, 50a ′) are provided on the base material layer, and the lid material strength is weakened in a region where the half-cuts are provided.   The half-cut is performed at a position passing through the center (C) of the sheet-like lid member or at a position opposite to the opening tab (21) with respect to the center (C). The sheet-like lid member according to claim 1, wherein the sheet-like lid member extends substantially orthogonal to a virtual line connecting the two.   3. The sheet-like lid material according to claim 1, wherein in the laminate, the polylactic acid layer-based film layer is located in the uppermost layer.   The sheet-like lid member according to any one of claims 1 to 3, wherein the half cut (50a ') is formed from an upper surface of the sheet-like lid member.

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