JP7357435B2 - Easy-to-peel lid material - Google Patents

Description

The present invention relates to an easily peelable lid material.

BACKGROUND ART Packaging bodies such as lids and bags are made of a laminate including at least two layers: an outer layer and an inner layer that is releasably laminated to the outer layer. In this laminate, an easily peelable layer is usually provided at the interface between the outer layer and the inner layer to make them easy to peel off, and by peeling off at least a part (separable part) of the outer layer, The inner layer can be exposed. Various laminates having such configurations have been proposed.

In Patent Document 1, the lid is composed of at least two layers, an inner layer and an outer layer, the lower surface of the inner layer is processed with a thermoplastic resin that enables heat sealing with the main body of the container, and the upper surface of the inner layer is coated with a partially A shakeout paper container is disclosed in which a peelable portion other than the opening is treated with a release agent, and a lid treated with an adhesive is used on the lower surface of the outer layer. Patent Document 1 states that the cut forming the partial opening may be perforated.

Note that Patent Document 2 discloses an easily peelable laminate comprising a first base layer and an easily peelable layer present on the first base layer, the easily peelable layer being discloses an easily peelable laminate, which is a layer of amorphous polyester having a glass transition temperature of 25° C. or less. Patent Document 2 also discloses a lid material having this easily peelable laminate.

Japanese Patent Application Publication No. 9-110077 Japanese Patent Application Publication No. 2017-144714

When lidded containers with lidding materials using half-cut lines are stacked, the weight of the lidded containers applies a load in the surface direction of the lidding materials, resulting in peeling between the layers of the laminate that makes up the lidding materials. or floating may occur.

Therefore, there is a need to provide an easily peelable lid material that suppresses interlayer peeling and/or lifting of the laminate that constitutes the lid material due to loads in the surface direction of the lid material.

After intensive study, the present inventors found that the above-mentioned problem could be solved by the following means, and completed the present invention. That is, the present invention is as follows:
<Aspect 1> An easily peelable lid material having a first base layer, an easily peelable layer, and a second base layer in this order in the lamination direction,
It is equipped with a main body part and a peeling tab protruding from the main body part in the surface direction,
The boundary between the main body portion and the peeling tab is defined by a peeling trigger half cut line formed from the second base layer side,
The first base layer can be peeled off from the second base layer by pinching the peeling tab and pulling in a peeling direction from the peeling tab toward the main body portion,
Half-cut for opening formation from the second base layer side so that an opening is formed in a part of the main body portion when the first base layer is peeled off from the second base layer. A line is formed,
The above half cut line for opening formation is
a first portion that is convex in the direction from the main body portion toward the peeling tab and is at least partially discontinuous; and a first portion that is convex and continuous in the peeling direction and that is continuous and at least partially consisting of a second portion that is formed to cross an area closer to the center of the main body portion than the first portion;
Easy-to-peel lid material.
<Aspect 2> A shape in which the second portion is at least partially included in a region surrounded by an imaginary line located at a position where the first portion is reversed to the second portion side. The easily peelable lid material according to aspect 1.
<Aspect 3> The easily peelable lid material according to aspect 1 or 2, wherein the second portion is formed of a curved line.
<Aspect 4> Aspects 1 to 3, wherein the first portion is formed along the inner periphery of an area where the easily peelable lid and the container are to be adhered. The easily peelable lid material according to any one of the items.
<Aspect 5> The region to be bonded is circular, the radius of curvature of the first portion is smaller than the radius of curvature of the inner circumference of the region to be bonded, and the radius of curvature of at least a portion of the second portion is , larger than the radius of curvature of the first part,
The easily peelable lid material according to aspect 4.
<Aspect 6> The first and second base material layers are a single layer of a resin layer or a metal layer, or a laminate having at least a resin layer or a metal layer, and the resin layer or The metal layer is in contact with the easily peelable layer, and the easily peelable layer is an amorphous polyester layer having a glass transition temperature of 60° C. or lower.
The easily peelable lid material according to any one of aspects 1 to 5.
<Aspect 7> Container having a flange part,
The easily peelable lid material according to any one of aspects 1 to 6, wherein the main body portion of the easily peelable lid material is joined to the flange portion of the container, whereby the container the lid material is sealed, and the outer periphery of the flange portion has a shape corresponding to the main body portion of the lid material;
Container with lid.
<Aspect 8> The lidded container according to aspect 7, further comprising the contents contained in the container.
<Aspect 9> The lidded container according to aspect 7 or 8, wherein the container is a paper container.

According to the present invention, the peeling and/or lifting of the layers of the laminate constituting the lid due to the load in the surface direction of the lid, and the layer remaining on the container side of the lid when the layers are partially peeled off. It is possible to provide an easily removable lid material with suppressed tearing.

FIG. 1 is a schematic diagram of a container with a lid having an easily peelable lid according to one embodiment of the present invention. FIG. 2 is a conceptual diagram when lidded containers having easily peelable lidding materials of the present invention are stacked. FIG. 3 is a diagram showing various aspects of the half-cut line for forming an opening in the lid material of the present invention. FIG. 4 is a diagram showing the shapes of half-cut lines for opening formation in Examples and Comparative Examples.

《Easy-peelable lid material》
As shown in FIG. 1, the easily peelable lid material 100 of the present invention has a first base layer 110, an easily peelable layer 130, and a second base layer 120 in this order in the lamination direction,
It includes a main body portion 102 and a peeling tab 104 protruding from the main body portion 102 in the surface direction,
The boundary between the main body portion 102 and the peeling tab 104 is defined by a peeling trigger half cut line 122 formed from the second base layer 120 side,
By pinching the peeling tab 104 and pulling in the peeling direction from the peeling tab 104 toward the main body portion 102, the first base layer 110 can be peeled off from the second base layer 120,
A half cut for opening formation is made from the second base layer 120 side so that an opening is formed in a part of the main body portion 102 when the first base layer 110 is peeled off from the second base layer 120. A line 124 is formed,
The opening forming half cut line 124 is
A first portion 124a that is convex in the direction from the main body portion 102 toward the peeling tab 104 and is at least partially discontinuous; A second portion 124b is formed to cross a region closer to the center of the main body portion 102 than the first portion 124a.
It consists of

In the present invention, "peeling the first base layer from the second base layer" refers to the separation between the first base layer and the easily peelable layer, or between the easily peelable layer and the second base layer. This means that the first base layer and the second base layer are separated due to delamination between the first base layer and the second base layer or cohesive failure of the easily peelable layer. After the first base layer is peeled off from the second base layer, the easily peelable layer may remain on at least one of the first base layer and the second base layer. .

When containers with lids having half-cut lines for opening are stacked as shown in FIG. 2, tensile stress may be applied in the plane direction. If the half cut line for opening formation is formed as a solid line as a whole, as a result of this stress, peeling or lifting may occur between the first base material layer and the second base material layer. Ta.

Furthermore, if an easily peelable lid is attached to a hygroscopic container, such as a paper container, and the lidded container is stored in a hot and humid environment during the summer, the shape of the container changes slightly due to moisture absorption, and as a result, Stress is applied to the lid material in the plane direction. At this time, the degree of stress applied is different between the second base material layer that is directly adhered to the container and the first base material layer that is present on the outside air side. As a result, a displacement occurs between the first base material layer and the second base material layer in the surface direction, and a portion of the second base material layer may be exposed from the outer periphery of the lid material. Ta. Such exposure will result in an unfavorable appearance, especially if the second substrate layer has a metal layer, such as an aluminum foil.

On the other hand, the present inventors have developed a half-cut line for forming an opening, as shown in FIG. 1(a).
A first portion 124a that is convex in the direction from the main body portion 102 toward the peeling tab 104 and is at least partially discontinuous; A second portion 124b is formed to cross a region closer to the center of the main body portion 102 than the first portion 124a.
We have found that the above problems can be solved by configuring the following.

More specifically, at least a portion of the first portion of the half-cut line that is convex in the direction from the main body toward the peeling tab is discontinuous, so that the second base layer itself Changes in shape in the planar direction are suppressed, and as a result, misalignment in the planar direction between the first base layer and the second base layer can be suppressed. Therefore, even if stress is generated in the surface direction of the lid material due to stacking of containers with lids and/or moisture absorption of the containers, peeling between the first base material layer and the second base material layer may occur. It is thought that it is possible to suppress floating and/or exposure of the second base material layer. In addition, in this first part, due to the adhesive force between the first base material layer and the second base material layer and the way stress is applied during peeling, the layer is easily peelable due to discontinuous points. And it is considered that the second base layer is less likely to break.

Furthermore, by making the second portion of the half-cut line that is convex in the peeling direction continuous, it is possible to suppress breakage of the second base material layer caused by discontinuous points. . Furthermore, by forming the second part so as to cross the area closer to the center of the main body than the first part, the second part is placed in the area closer to the center where external stress in the plane direction is less likely to be applied. As a result, the influence of the above-mentioned stress on the second part is suppressed, and as a result, even around the second part, there is a gap between the first base material layer and the second base material layer. It is thought that peeling and lifting can be suppressed.

Below, each component in the surface direction of the lid material of the present invention will be explained.

<Body part>
The main body portion is the portion of the easily peelable lid material of the present invention excluding the peeling tab and the opening tab. In particular, the main body portion can be a portion that occupies within the outer periphery of the flange portion of the container when joined to the container, that is, a portion that has a shape corresponding to the shape of the outer periphery of the flange portion of the container to be sealed.

The shape of the main body portion may be, for example, a polygon such as a square or a rectangle, a rounded polygon such as a rounded square or a rounded rectangle, a circle, an ellipse, or the like.

<Peeling tab>
The peeling tab protrudes from the main body portion. The boundary between the main body portion and the peeling tab is defined by a peeling trigger half cut line formed from the second base layer side. By pinching this peeling tab and pulling it in the peeling direction from the peeling tab toward the main body part, the peelable layer can be removed between the easily peelable layer and the second base layer, or between the easily peelable layer and the first base layer. The layers can be peeled off.

<Half cut line>
The half cut line is a cut formed from the surface of the easily peelable lid material to a depth less than the thickness of the easily peelable lid material.

For example, the half cut line can be formed by inserting a cutting machine such as a cutter into the surface of the easily peelable lid material. Further, the half-cut line can be formed on the first base layer side and/or the second base layer side.

For example, the half-cut line on the second base layer side is carved from the surface of the second base layer of the easily peelable lid material to a depth that penetrates at least a portion or all of the second base layer. ing.

The half-cut line on the second base layer side is carved at a depth that penetrates at least a portion or all of the second base layer in the thickness direction of the second base layer of the easily peelable lid material. has been done. Therefore, the depth of the second base layer half cut line is approximately equal to the thickness of the second base layer of the easily peelable lid material.

For example, the half-cut line on the second base layer side can be formed to a depth that reaches the easily peelable layer from the surface of the second base layer. In this case, the first base layer can be peeled off at the interface between the second base layer and the easily peelable layer. Further, the half-cut line on the second base layer side can be formed from the surface of the second base layer until it penetrates the easily peelable layer. In this case, the first base layer can be peeled off at the interface between the first base layer and the easily peelable layer.

Below, various aspects of the half-cut line will be described in the case where the first base layer is used as the outer layer and the second base layer is used as the inner layer in the easily peelable lid material.

(Half cut line for opening formation)
The half cut line for opening formation is formed from the second base layer side so that when the first base layer is peeled off from the second base layer, an opening is formed in a part of the main body part. has been done. When the first base layer is peeled off from the second base layer, this part of the region is separated from the other part of the second base layer together with the first base layer, and the second base layer is separated from the second base layer. An opening is formed in the material layer.

The opening forming half-cut line is composed of a first part and a second part. Below, the first part and the second part will be explained.

(Half cut line for opening formation: first part)
The first portion is convex in the direction from the main body portion toward the peeling tab, and is at least partially discontinuous. The first portion may be entirely discontinuous perforations, as shown in FIGS. 3(a), (c) and (d), or may be perforated, as shown in FIG. 3(b). A portion may be discontinuous.

As shown in FIG. 1(a), the first portion is formed along the inner periphery of a region 126 to be bonded where the easily peelable lid material and the container are to be bonded. is preferable from the viewpoint of ensuring a sufficient area for the opening. Here, "along" means that the distance between the inner periphery of the area to be bonded and the first portion is 10 mm or less, 8 mm or less, or 5 mm or less. This distance may be greater than 0 mm, greater than or equal to 1 mm, or greater than or equal to 2 mm.

In particular, when the area to be bonded is circular, the radius of curvature of the first portion may be smaller than the radius of curvature of the inner circumference of the area to be bonded.

(Half cut line for opening formation: second part)
The second portion is convex in the peeling direction, is continuous, and is formed so that at least a portion thereof crosses a region closer to the center of the main body portion than the first portion.

Specifically, the second portion has a shape that is at least partially included in a region that is surrounded by an imaginary line that exists at a position where the first portion is reversed to the second portion side. It's fine. For example, the second portion 124b is a trapezoid included in a region surrounded by a virtual line 124a' located at a position where the first portion is reversed, as shown in FIG. 3(c). Alternatively, as shown in FIG. 3(d), it may be a triangle included in such a region.

Among other things, the second portion is composed of a curved line as shown in FIGS. 3(a) and (b), so that when the first base layer is peeled off from the second base layer, This is preferable from the viewpoint of suppressing the concentration of force for peeling and, as a result, suppressing breakage of the lid material. In this case, as shown in FIGS. 3(a) and 3(b), the second part has both ends overlapping the line 124a' which is the inversion of the first part, and the center part of the second part overlaps with the line 124a' which is the reverse of the first part. It may be a curved line that crosses an area closer to the center of the main body portion than the line 124a' that is the inversion of the line 124a'.

In particular, when the area to be bonded is circular, the radius of curvature of at least a portion of the second portion may be larger than the radius of curvature of the first portion.

(Half cut line for triggering peeling)
The half-cut line for triggering peeling is generally a half-cut line used as an element for peeling off one base layer from another base layer, especially as an element for peeling an outer layer from an inner layer, that is, as a trigger for peeling. be. In particular, in the lid material of the present invention, this half-cut line is a half-cut line formed from the second base layer side.

Next, the layer structure of the lid material of the present invention will be explained.

<First base material layer>
The first base layer is a layer that is present on the easily peelable layer. The first base material layer can be used as a single layer or as a stack of arbitrary layers.

In particular, when the easily peelable layer mentioned below is a layer of amorphous polyester, the first base layer is a single layer of resin layer or metal layer, or at least one resin layer or metal layer. From the viewpoint of affinity with amorphous polyester, it is preferable that the laminate has the following properties. In this case, in particular, the layer in contact with the easily peelable layer of the first base layer can be a resin layer or a metal layer.

When the first base layer is a laminate, the first base layer may include an optional sealant layer and other layers as layers not in contact with the easily peelable layer.

(resin layer)
As the resin layer, commercially available films, extruded resins, and the like can be used as appropriate.

For example, the films include polyethylene terephthalate film (PET), low density polyethylene film (LDPE), medium density polyethylene film (MDPE), high density polyethylene film (HDPE), linear low density polyethylene film (LLDPE), and polypropylene film. (PP), nylon film (Ny), etc. may be used alone or in combination.

Examples of extruded resins include low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), ethylene methacrylic acid copolymer (EMAA), and ethylene acrylic acid copolymer. Polymers (EAA) and the like may be used alone or in combination.

Furthermore, the resin layer may include other layers such as an adhesive layer, an inorganic vapor deposited layer, and a barrier coat layer.

(metal layer)
As the metal layer, for example, metal foil such as aluminum foil, copper foil, or titanium foil, or alloy foil such as aluminum alloy foil or stainless steel foil can be used.

(Sealant layer)
The sealant layer is a layer for heat-sealing the easily peelable lid to other structures such as containers. In particular, in the first base material layer and the second base material layer of the present invention, it is a layer that is not in contact with the easily peelable layer among the outermost layers.

The material of the sealant layer is selected depending on the material to be sealed, and examples include LDPE, LLDPE, PP, ethylene methacrylic acid copolymer (EMAA), ethylene acrylic acid copolymer (EAA), ionomer resin, ethylene acetic acid. A resin such as vinyl copolymer (EVA) may be used. These resins may be in the form of, for example, stretched or unstretched films, molten resins for extrusion lamination, paints for hot melt, and the like.

Further, as the sealant layer, a commercially available easy-peel resin or easy-peel sealant film that is not composed of these resins may be used.

(other layers)
Other layers include a paper layer, an adhesive layer, a printing layer, and the like. Lamination of other layers can be performed by, for example, extrusion lamination such as sand lamination or back lamination, dry lamination, or the like.

As the paper layer, coated paper, art paper, etc. can be used.

As the adhesive layer, for example, a dry laminating adhesive, an anchor coat adhesive, a hot melt adhesive, a water-soluble adhesive, an emulsion adhesive, a non-solvent laminating adhesive, a thermoplastic resin for extrusion lamination, etc. can be used. I can do it.

The printed layer may be, for example, a printed layer showing character information, a mark printed layer, a light-shielding printed layer, a pattern printed layer, a photographic printed layer, or the like. Further, the printed layer can be formed by gravure printing, flexographic printing, or the like.

<Easily peelable layer>
The easily peelable layer may be an easily peelable resin layer formed of an easily peelable resin, a layer of amorphous polyester, or a combination thereof. In particular, when imparting good peelability and resealability to the easily peelable layer, the easily peelable layer is a layer of amorphous polyester, particularly an amorphous polyester having a glass transition temperature of 60°C or lower. It is preferable that the layer is . Regarding such an easily peelable layer having easy peelability and resealability, the description in Patent Document 2 can be referred to.

(Easy peelable resin)
The easily peelable resin may be, for example, a single polyolefin, or a resin obtained by mixing a polyolefin with a cyclic olefin copolymer (COC) at a predetermined ratio.

Examples of the polyolefin include polyethylene resin, polypropylene resin, etc., and low density polyethylene (LDPE) is preferred. Examples of the LDPE include "Petrosen" (trade name) manufactured by Tosoh Corporation, "Suntec" (trade name) manufactured by Asahi Kasei Chemicals Corporation, and the like.

The MFR (Melt Flow Rate) of polyolefin is 0.01 g/10 minutes or more, 0.1 g/10 minutes or more, or It may be 1.0 g/10 minutes or more, and may be 60 g/10 minutes or less, 20 g/10 minutes or less, or 10 g/10 minutes or less.

The density of the polyolefin may be greater than or equal to 0.89 g/cm ³ , and the density may be less than or equal to 0.94 g/cm ³ .

Cyclic olefin copolymer (COC) is made by combining an α-olefin and a cyclic olefin in a hydrocarbon solvent such as hexane, heptane, octane, cyclohexane, benzene, toluene, or xylene, using a so-called Ziegler catalyst, a metallocene It refers to a copolymer that can be obtained by preparing a catalyst such as a catalyst. Examples of such copolymers include "APEL" (trade name) manufactured by Mitsui Chemicals, Inc., and the like.

The MFR of COC is based on JIS K7210 and is 0.1 g/10 minutes or more, 1.0 g/10 minutes or more, or 2.0 g/10 when measured under the conditions of temperature 190 ° C / load 2.16 kg. The MFR may be 40 g/10 min or less, 20 g/10 min or less, or 10 g/10 min or less at a temperature of 190°C.

The interfacial peel strength of the easily peelable resin layer can be adjusted by changing the mixing ratio of LDPE and COC. The content of COC in the easily peelable resin may be 1% by mass or more, or 3% by mass or more, and this content may be 24% by mass or less, 20% by mass or less, 15% by mass or less, 10% by mass or less. It may be less than 7% by mass, or less than 7% by mass. Within this range, the COC content facilitates interfacial peeling between the first or second base layer and the easily peelable resin layer, and also facilitates control of the peel strength of both. preferable.

(Amorphous polyester)
The amorphous polyester may have a glass transition temperature of 60°C or less. This glass transition temperature can be 60°C or less, 55°C or less, or 50°C or less, and can be -50°C or more, -40°C or more, -30°C or more, or -20°C or more. . Within the above range, it is possible to ensure easy peelability and resealability without any practical problems, but from the viewpoint of not causing peeling with abnormal noise or catching (pulse peeling), that is, from the viewpoint of producing smooth peeling. Therefore, the glass transition temperature is preferably 45°C or lower. In addition, from the viewpoint of obtaining good peelability at room temperature, the glass transition temperature may be -20°C or higher, -10°C or higher, 0°C or higher, 10°C or higher, 20°C or higher, or higher than 25°C. preferable.

Here, "amorphous" in the present invention means that there is no clear melting peak when the temperature is raised from -100°C to 300°C at a rate of 20°C/min using a differential scanning calorimeter (DSC). It means that.

In addition, the glass transition temperature (Tg) in this specification is determined by heat flux differential scanning calorimetry (heat flux DSC) at a heating rate of 10°C/min in accordance with JIS K7121 (1987). It refers to the glass transition temperature (°C) at the midpoint of the test piece, and JIS K7121 ``Measuring the glass transition temperature after a certain heat treatment'' shall be adopted for conditioning the test piece.

The number average molecular weight of the amorphous polyester is preferably 100,000 or less, 90,000 or less, 80,000 or less, 70,000 or less, 60,000 or less, or 50,000 or less from the viewpoint of preventing stickiness of the easily peelable layer after peeling. It is preferable that it is 5000 or more, 6000 or more, 7000 or more, 8000 or more, 9000 or more, or 10000 or more from the viewpoint of ensuring appropriate peel strength.

Here, the number average molecular weight in this specification means the number average molecular weight measured by gel permeation chromatography using a tetrahydrofuran solvent and a polystyrene standard.

Such an amorphous polyester is an amorphous polyester containing 50 mol% dicarboxylic acid component and 50 mol% diol component, 30 mol% or more of terephthalic acid, and 25 mol% or more of ethylene. Amorphous polyesters containing glycol and 5 to 45 mol % of other dicarboxylic acid components and/or other diol components can be used.

Other dicarboxylic acid components include isophthalic acid, orthophthalic acid, 1,5-naphthalic acid, 2,6-naphthalic acid, 4,4'-diphenyldicarboxylic acid, 2,2'-diphenyldicarboxylic acid, 4,4' - Aromatic dibasic acids such as diphenyl ether dicarboxylic acid, adipic acid, azelaic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 4-methyl-1 , 2-cyclohexanedicarboxylic acid, dimer acid, and other aliphatic and alicyclic dicarboxylic acids.

Other diol components include propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1 , 5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, cyclohexane Dimethanol, neopentyl hydroxypivalic acid ester, 1,9-nonanediol, 2-methyloctanediol, 1,10-dodecanediol, 2-butyl-2-ethyl-1,3-propanediol, tricyclodecane dimethanol etc.

When the easily peelable layer is an amorphous polyester layer, the easily peelable layer is preferably present in an amount of 4.0 g/m ² or less from the viewpoint of achieving good easy peelability and resealability. . This amount can be 3.8 g/m ² or less, or 3.5 g/m ² or less, and 0.1 g/m ² or more, 0.3 g/m ² or more, or 0.5 g/m ² It can be more than that.

<Second base material layer>
The second base layer is a layer that is present on the easily peelable layer on the side where the first base layer is not present. The second base material layer can be used as a single layer or in a laminated form.

In particular, when the above-mentioned easily peelable layer is an amorphous polyester layer, the second base layer is a single layer of a resin layer or a metal layer, or has at least a resin layer or a metal layer. From the viewpoint of affinity with the amorphous polyester, it is preferable that the laminate be a laminate that has the following properties. In either case, the layer in contact with the easily peelable layer of the second base layer is a resin layer or a metal layer. The second base layer may be the same as or different from the first base layer.

As the resin layer, metal layer, and optional sealant layer and other layers, those listed for the first base layer can be used.

《Container with lid》
The container with a lid of the present invention includes a container having a flange portion and the above-mentioned easily peelable lid material. The main body portion of the easily peelable lid member is joined to the flange portion of the container, thereby sealing the container.

A container with a lid can be opened by peeling off the easily peelable lid material from the container.

The lidded container may further include contents contained in the container.

<container>
The container has a flange.

The outer periphery of this flange portion has a shape corresponding to the main body portion of the lid member.

The material of the container can be arbitrarily selected depending on the contents of the container.

For example, to prevent the contents of the container from seeping out of the container, the container can be formed of a material that is impermeable to the contents. More specifically, the container may be formed from a resin such as polypropylene or polystyrene.

Further, the container may be a paper container. Here, the paper container may be a container made only of paper, or may be a container in which a resin such as polyolefin is laminated on the surface of a paper container base material formed into the shape of the container. . As mentioned above regarding the easily peelable lid material, when a paper container is used, by using the easily peelable lid material of the present invention, the first base material layer and the second base material layer are separated due to moisture absorption of the container. This makes it possible to suppress displacement in the plane direction between the material layer and the material layer.

<Contents>
The contents may be contained in a container.

The contents may be, for example, solids, gels, etc., and may be, for example, chemicals, cosmetics, detergents, fragrances, medicines, non-edible items such as wet tissues, etc.

Moreover, examples of the contents include heated foods such as instant noodles, chilled foods, and frozen foods, and non-heated foods such as snacks and gummy candies.

The present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

《Opening test and moisture absorption test》
<Production of container with lid>
(Example)
Prepared the materials shown below:
Paper (basis weight: 79.1 g/m ² ): Tokubishi Art, Mitsubishi Paper Mills Co., Ltd. PET (thickness: 12 μm): PET, Unitika Co., Ltd. Easy peeling layer: Vylon 55SS, Toyobo Co., Ltd., Tg: -15 ℃
PET (thickness: 12 μm): PETB, Unitika Co., Ltd. Aluminum foil (thickness: 6.5 μm): 1N30, Toyo Aluminum Co., Ltd. Dry laminating adhesive: Takelac A-620/Takenate A-65, Mitsui Chemicals Co., Ltd. EMAA (Thickness: 18μm): Nucrel AN4225C, Mitsui DuPont Polychemical Co., Ltd. Sealant layer (thickness: 15μm): Toyomelt ER, Toyo Adre Co., Ltd.

The laminate obtained here was paper (basis weight: 79.1 g/m ² )//PET (12 μm)/easy peel layer (1.0 g)/PET (12 μm)//AL (6.5 μm)/ It had a layer configuration of EMAA (18 μm)/sealant (15 μm) (where “//” represents a dry lamination adhesive).

1. Using a dry laminator, set the amount of dry laminating adhesive applied to a dry weight of 2.5 g/m2 or ^more , and then attach paper "Tokubishi Art" and PET film "PET" to dry laminating adhesive "Takelac A-620". /Takenate A-65" to obtain member a (paper (basis weight: 79.1 g/m ² )//PET (12 μm)) as the first base layer.

2. Using a dry laminator, set the amount of dry laminating adhesive applied to a dry weight of 2.5 g/m2 or ^more , and then attach the aluminum foil and PET film "PETB" to the dry laminating adhesive "Takelac A-620/Takenate A-". 65'' to obtain member b (PET (12 μm)//AL (6.5 μm)).

3. Amorphous polyester "Vylon 55SS" as an easily peelable layer dissolved in a solvent was diluted with ethyl acetate so that the content of amorphous polyester was 15% by mass to prepare a solution of amorphous polyester. did. Using a dry laminator, set the coating amount to a dry weight of 1.5 g/ ^m2 or less, apply this amorphous polyester solution to the PET film "PET" side of member a, and then apply it to member b. The "PETB" side of the PET film was crimped to obtain member c.

4. Using an extrusion laminator, EMAA "Nucrel AN4225C" was extruded onto aluminum foil "1N30" of member c at a temperature of about 280° C. with a film thickness setting of 18 μm to obtain member d.

5. Using an extrusion laminator, set the film thickness to 15 μm at a temperature of approximately 240°C, extrude "Toyomelt ER" as a sealant layer onto EMAA "Nucrel AN4225C" of member d, and form the evaluation laminate e. Obtained.

In the above evaluation laminate e, paper (basis weight: 79.1 g/m ² )//PET (12 μm) corresponds to the first base layer in the present invention, and PET (12 μm)//AL( 6.5 μm)/EMAA (18 μm)/Sealant (15 μm) corresponds to the second base material layer in the present invention.

As shown in FIG. 4(a), the produced laminate e for evaluation was coated with a rotary die cutter to form an opening and a peel trigger at a depth from the sealant layer to the easily peelable layer of the laminate e for evaluation. A half-cut line was carved and the outer periphery of the lid was fully cut to obtain an easily peelable lid material with a diameter of 112 mm.

The above-mentioned easily peelable lid material was heat-sealed to a paper container with a diameter of φ108.5 mm whose inner surface was laminated with LDPE under conditions of a temperature of 150°C, a time of 0.7 seconds, and a pressure of 65 kg to obtain a container with a lid of the example. Obtained.

(Comparative Examples 1 to 3)
The lids of Comparative Examples 1 to 3 were prepared in the same manner as in the example except that the shape of the half-cut line for opening formation shown in FIG. 4(a) was changed to the shape shown in FIGS. 4(b) to 4(d). I got a container with it.

<Evaluation: Opening test>
The first base layer was peeled off from the second base layer by pinching the peeling tab of each lidded container produced and pulling in the peeling direction, and the presence or absence of breakage of the lid material was visually confirmed. In Table 1 below, five samples were evaluated in the same manner, and the number of samples with no breakage is listed.

<Evaluation: Moisture absorption test>
Each container with a lid was stored alternately for 3 hours each in a normal temperature environment (temperature 25°C, relative humidity 50%) and a high temperature and humid environment (temperature 40°C, relative humidity 90%). It was stored for 12 hours. Next, whether or not the second base material layer was exposed from the outer peripheral side of the lid material was visually evaluated. The evaluation was performed by checking whether the aluminum foil of the second base layer was exposed. In Table 1, cases in which the second base material layer was exposed are marked as ×, and cases in which the second base material layer was not exposed are marked as ○.

The results are shown in Table 1. In Table 1, the "first part" means the part of the opening forming half-cut line that is convex in the direction from the main body part of the lid material toward the peeling tab, and the "second part" means the part of the opening forming half cut line that is convex in the peeling direction. Regarding the "second part" in Table 1, whether or not at least a part is formed so as to cross an area closer to the center of the main body part than the first part is determined by "presence or absence of crossing on the center side." ” is mentioned.

From Table 1, the first part is discontinuous, and the second part is continuous and is formed so that at least a part thereof crosses a region closer to the center of the main body part of the lid than the first part. The container with a lid having a half-cut line for forming an opening according to the embodiment, which is composed of two parts, is well suppressed from breaking the lid material due to opening and from exposing the second base material layer due to moisture absorption. You can understand that.

On the other hand, it can be seen that in the containers with lids of Comparative Examples 1 and 2, in which both the first part and the second part are continuous, the second base layer was exposed due to moisture absorption. From this, it can be seen that in the containers with lids of these comparative examples in which both the first part and the second part are continuous, the difference in the plane direction between the first base material layer and the second base material layer is It can be seen that the deviation has not been sufficiently suppressed.

Furthermore, in the lidded container of Comparative Example 3 in which both the first portion and the second portion were discontinuous, the lower layer of the lid material was broken due to peeling near the second portion.

《Press test》
In order to easily confirm the effect that the difference in the shape of the half-cut line for opening formation has on the pressing strength, we conducted a test by changing the laminated configuration used in the above evaluation (opening test, moisture absorption test). Ta.
However, the shape of the half-cut line for forming the opening was the same as in the example, comparative example 1, comparative example 2, and comparative example 3.

<Preparation of container with lid for pressure test>
(Container with lid A)
Prepared the materials shown below:
Paper (basis weight: 79.1 g/m ² ): Tokubishi Art, Mitsubishi Paper Mills Co., Ltd. LDPE (thickness: 15 μm): Petrocene 205, Tosoh Corporation Aluminum foil (thickness: 6.5 μm): 1N30, Toyo Aluminum EMAA Co., Ltd. (thickness: 18 μm): Nucrel AN4225C, Mitsui DuPont Polychemical Co., Ltd. Sealant layer (thickness: 15 μm): Toyomelt ER, Toyo Adre Co., Ltd.

The laminate obtained here had a layer structure of paper (basis weight: 79.1 g/m ² )/LDPE (15 μm)/AL (6.5 μm)/EMAA (18 μm)/sealant (15 μm). .

1. Using an extrusion laminator, set the film thickness to 15 μm at a temperature of about 320°C to about 340°C, extrude LDPE between the paper “Tokubishi Art” and the aluminum foil “1N30”, and sand laminate. Thus, member a was obtained.

2. Using an extrusion laminator, EMAA "Nucrel AN4225C" was extruded onto the aluminum foil "1N30" side of member a at a temperature of about 280° C. with a film thickness setting of 18 μm to obtain member b.

3. Using an extrusion laminator, set the film thickness to 15 μm at a temperature of approximately 240°C, extrude "Toyomelt ER" as a sealant layer onto "Nucrel AN4225C" on EMAA of member b, and form laminate c for evaluation. Obtained.

As shown in FIG. 4(a), a half-cut line for forming an opening and for triggering peeling is formed on the produced laminate for evaluation at a depth from the sealant layer to the LDPE layer of the laminate for evaluation c using a rotary die cutter. was engraved and the outer periphery of the lid was fully cut to obtain a lid material for pressure testing with a diameter of 112 mm.

A paper container with a diameter of φ108.5 mm whose inner surface was laminated with LDPE was heat-sealed with the lid material for the pressure test at a temperature of 150°C, a time of 0.7 seconds, and a pressure of 65 kg to form an opening similar to that in the example. A container A with a lid having a shape of a half-cut line was obtained.

Containers with lids B~ I got a D.

<evaluation>
Using a PP jig with a bottom surface of 72 mm in diameter, the lid material of each lidded container produced was pressed for 5 seconds under loads of 1 kg, 2 kg, 3 kg, 4 kg, and 5 kg, respectively. After pressing, the presence or absence of breakage of the lid material caused by the half cut line for forming the opening was visually observed. In Table 2 below, the maximum load at the time of breakage is listed.

From Table 2, the first part is discontinuous, and the second part is continuous and is formed so that at least a part thereof crosses a region closer to the center of the main body part of the lid material than the first part. It can be seen that the container with a lid having the half-cut line for forming the opening of the example, which is composed of two parts, is prevented from breaking due to pressure.

On the other hand, it can be confirmed that in the lidded containers of Comparative Examples 1 and 2 in which both the first portion and the second portion are continuous, the lid material may break due to pressure even under a weak load. From this, it can be understood that the fact that either the first portion or the second portion is discontinuous has a significant effect on the compressive strength.

100 Easily peelable lid material 102 Main body portion 104 Peeling tab 106 Opening tab 110 First base layer 120 Second base layer 130 Easily peelable layer 122 Half cut line for peeling trigger 124 Half cut line for opening formation 124a First part 124a' Virtual line existing at the position where the first part is reversed 124b Second part 126 Area to be bonded 200 Container 202 Flange part 204 Storage part 300 Container with lid

Claims (9)

An easily peelable lid material comprising a first base layer, an easily peelable layer, and a second base layer in this order in the lamination direction,
A main body portion and a peeling tab protruding from the main body portion in the surface direction,
The boundary between the main body portion and the peeling tab is defined by a peeling trigger half cut line formed from the second base layer side,
The first base layer can be peeled off from the second base layer by pinching the peeling tab and pulling in a peeling direction from the peeling tab toward the main body portion,
A half-cut for opening formation from the second base layer side so that an opening is formed in a part of the main body portion when the first base layer is peeled from the second base layer. A line is formed,
The half cut line for forming the opening is
a first portion that is convex in the direction from the main body portion toward the peeling tab and is at least partially discontinuous; and a first portion that is convex in the peeling direction, continuous, and at least partially discontinuous; consisting of a second portion that is formed to cross a region closer to the center of the main body portion than the first portion;
Easy-to-peel lid material. The second portion has a shape that is at least partially included in a region that is surrounded by an imaginary line that is located at a position where the first portion is reversed to the second portion side. Item 1. The easily peelable lid material according to item 1. The easily peelable lid material according to claim 1 or 2, wherein the second portion has a curved line. Any one of claims 1 to 3, wherein the first portion is formed along the inner periphery of a region where the easily peelable lid material and the container are to be bonded. Easily removable lid material described in section. The area to be bonded is circular, the radius of curvature of the first portion is smaller than the radius of curvature of the inner circumference of the area to be bonded, and the radius of curvature of at least a portion of the second portion is smaller than the radius of curvature of the inner circumference of the area to be bonded. is larger than the radius of curvature of the part of
The easily peelable lid material according to claim 4. The first and second base material layers are a single resin layer or a metal layer, or a laminate having at least a resin layer or a metal layer, and the resin layer or the metal layer is , the easily peelable layer is in contact with the easily peelable layer, and the easily peelable layer is an amorphous polyester layer having a glass transition temperature of 60° C. or lower.
The easily peelable lid material according to any one of claims 1 to 5. a container having a flange;
The easily peelable lid according to any one of claims 1 to 6, wherein the main body portion of the easily peelable lid is joined to the flange portion of the container, whereby the container a lid material that seals the lid material, and an outer periphery of the flange portion has a shape corresponding to the main body portion of the lid material;
Container with lid. The lidded container according to claim 7, further comprising a content contained in the container. The lidded container according to claim 7 or 8, wherein the container is a paper container.

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