JP4190868B2 - Easy-open packaging for containers and retort foods - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention comprises a container and For retort food The present invention relates to an easily openable package.
[0002]
[Background]
2. Description of the Related Art Conventionally, a packaging body including a container formed by thermoforming a sheet for packaging foods and the like, and a flange portion formed on the periphery of an opening for storing an object to be packaged, and a lid member that closes the opening. Is used. This package is obtained by inserting a food or the like into a container and then heat-sealing a lid material on the flange portion of the container. Such a package preferably has a high heat seal strength and a high sealing property from the viewpoint of preservation of an article to be packaged. However, from the viewpoint of opening at the time of use, it is desirable that it can be easily opened, and a package having such contradictory performance is required.
[0003]
In order to satisfy this requirement, there is a method of adjusting the seal strength by selecting the resin of the seal layer of the flange portion of the container and the seal layer of the lid, mixing the resin, and the like. However, in this method, there is a problem that the seal strength is low and it is difficult to stabilize due to influences such as heat sealing conditions and adhesion of the package to the flange portion.
In order to solve this problem, a container in which the delamination strength between the innermost layer and the next layer of the container is controlled to about 5 to 15 N / 15 mm has been proposed (conventional example 1).
In this container, an annular cut is formed in the innermost layer of the flange portion of the container, and a lid is sealed on the outer peripheral side of the cut. At the time of opening, a part of the innermost layer of the container sealed by the lid material is peeled off together with the lid material.
In addition, the innermost layer of the multilayer film or sheet and the next layer (intermediate layer) adjacent to the innermost layer are used as a cohesive fracture resin layer, and the cohesive fracture strength of the next layer is made lower than the cohesive fracture strength of the innermost layer. A method has also been proposed (see Conventional Example 2: Patent Document 1). The multilayer film and sheet can be used as a lid, container, and bag. For example, when the multilayer film and sheet are used as a lid, the innermost layer is brought into contact with the flange portion of the container and sealed. To do. Then, when the lid member is peeled off, the edge is cut off, and the portion of the innermost layer and the next layer of the lid member that is heat sealed to the flange portion of the container remains on the flange portion and is opened.
[0004]
[Patent Document 1]
Japanese Patent No. 2869136 (page 1 to page 6, FIG. 4)
[0005]
[Problems to be solved by the invention]
However, in the method of opening by delamination as in Conventional Example 1, there is a problem that the peel strength is likely to change due to changes in heating conditions during sheet forming and container thermoforming.
Further, in the method of Conventional Example 2, since the innermost layer is a cohesive failure layer, there is a limit to the sealing performance. Moreover, the resin which can be used for an innermost layer etc. is limited and there exists a problem that the selection range of resin is narrow. Therefore, for example, it is difficult to improve chemical resistance, oil resistance, and heat resistance according to applications.
Further, in the method of Conventional Example 2, since the peeling is performed due to the edge cut, it is necessary to reduce the thickness of the lid material or to consider the material of the lid material. There is also the problem of being narrow.
[0006]
The object of the present invention is to have a high sealing performance and easy opening, satisfy the performance according to the application, and cover a wide range of materials. The Containers that can be selected and used and For retort food It is to provide an easy-open packaging body.
[0007]
[Means for Solving the Problems]
Therefore, the present invention intends to achieve the object by adopting the following configuration.
Specifically, the container of the present invention is A container having a bottom surface and a side surface which is integrally formed by rising from the bottom surface and has an opening at the top, and a flange portion extending outward is integrally formed on the periphery of the opening, Base material layer, formed on this base material layer, containing polyolefin resin and soft resin or elastomer And the layer thickness is not less than 20 μm and not more than 200 μm A cohesive breakable resin layer and a polyolefin resin formed on the cohesive breakable resin layer And the layer thickness is not less than 40 μm and not more than 200 μm A non-cohesive and destructible resin layer, the non-cohesive and destructible resin layer is positioned on the inner surface of the container, and the non-cohesive and destructible resin layer of the flange portion is formed with an annular cut. Features.
[0008]
Here, the cohesive fracture resin layer means that when this layer is firmly adhered to another strong film and then subjected to a peel test, this layer breaks in the layer, and the peel strength is 25 N / 15 mm or less. (JIS K 6854).
The soft resin or elastomer of the cohesive fracture resin layer preferably has an elastic modulus of 200 MPa or less, particularly 150 MPa or less.
Examples of the soft resin of the cohesive fracture resin layer include an ethylene-polar vinyl compound copolymer. For example, ethylene-acrylic acid copolymer (EAA), ethylene-methyl acrylate copolymer (EMA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl Known ethylene-acrylic acid copolymers such as acrylate copolymer (EEA), ethylene-ethyl acrylate-maleic anhydride copolymer (EEA-MAH), ionomer resin, or ethylene-vinyl acetate copolymer Can be illustrated.
[0009]
The elastomer of the cohesive fracture resin layer is an olefin elastomer (density 900 kg / m between amorphous ethylene and α-olefin such as propylene and butene). ^Three Examples thereof include the following copolymers), styrene elastomers (styrene-butadiene block copolymers, styrene-butadiene random copolymers, etc.), hydrogenated products thereof, and the like.
The polyolefin resin of the cohesive fracture resin layer is not particularly limited, and polypropylene resins such as homopolypropylene, random polypropylene, block polypropylene, high density polyethylene, high pressure method low density polyethylene, linear low density polyethylene, etc. The polyethylene resin can be illustrated. In the present invention, since this cohesive fracture resin layer is not a surface layer, there is no need to consider heat resistance and the like, and the degree of freedom in selection is high.
[0010]
When a cover material is welded to the container and a force for peeling the cover material is applied, cohesive failure occurs in the cohesive failure resin layer. In addition, since a cut is formed in the non-cohesive breakable resin layer, if a lid is welded to the outer peripheral side of the cut, the outer peripheral portion of the non-cohesive breakable resin layer is cut together with the cover material. And the cohesive breakable resin layer that has caused cohesive failure can be easily peeled off. Therefore, easy-openability can be satisfied.
Since the non-cohesive and destructible resin layer is formed on the cohesive and destructible resin layer, by changing the resin used for the non-cohesive and destructible resin layer, it is possible to make a container having performance according to the application. . For example, when a container having chemical resistance, oil resistance, and heat resistance is desired, the non-cohesive breakable resin layer may be formed of a chemical resistance, oil resistance, and heat resistant resin.
Further, as described above, the non-cohesive fracture resin layer may be changed according to the use of the container, and the resin used for the cohesive fracture resin layer is not limited to the use of the container. The range of selection can be expanded.
[0011]
Further, since the non-cohesive breakable resin layer is formed on the cohesive breakable resin layer, it is possible to prevent the generation of a soft resin or elastomer odor in the cohesive breakable resin layer.
Furthermore, as described above, in the case of delamination, the delamination strength tends to change due to thermal history, molding such as stretching, layer thickness, and the like. Therefore, it may be difficult to control the peel strength to be constant. On the other hand, since this invention raise | generates cohesive failure within a cohesive failure resin layer, and peels, it can make peeling strength constant. Further, the peel strength can be further stabilized by preventing the interface between the cohesive fracture resin layer and the base material layer from peeling off.
[0012]
In addition, since the cut is formed in the non-cohesive breakable resin layer, it is possible to increase the thickness of the non-cohesive breakable resin layer or use a resin with a high melting point, high strength, and high rigidity. It is.
Further, when the cut is not formed in the non-cohesive breakable resin layer, it is necessary to perform peeling by cutting off the edge of the heat seal portion between the lid member and the non-cohesive breakable resin layer. In this case, it is necessary to reduce the thickness of the lid material or to consider the material of the lid material. On the other hand, in the present invention, since the cut is formed in the non-cohesive fracture resin layer, it is not necessary to consider the peeling due to edge breakage, the thickness of the lid can be increased, and the aluminum foil A lid material containing a layer or the like can also be used. Therefore, the range of selection of the lid material can be expanded.
[0013]
In this case, the base material layer is a polyolefin resin, and the cohesive failure resin layer has an ethylene-polar vinyl compound copolymer that is a soft resin, and the non-cohesive fracture resin layer polyolefin resin. Is preferably a polypropylene resin having a melting point of 140 ° C. or higher.
Since a polypropylene resin having a melting point of 140 ° C. or higher is used for the non-cohesive breakable resin layer serving as the inner surface of the container, the heat resistance can be improved.
Further, since the ethylene-polar vinyl compound copolymer is contained as the soft resin of the cohesive failure resin layer, the cohesive peelability can be improved.
[0014]
Furthermore, the cohesive failure resin layer preferably contains 50 to 95 wt% of a polypropylene resin and 5 to 50 wt% of an ethylene-polar vinyl compound copolymer.
If the ethylene-polar vinyl compound copolymer is less than 5 wt%, the opening strength will be too high. In addition, when the ethylene-polar vinyl compound copolymer is more than 50 wt%, the adhesive strength between the base material layer and the cohesive fracture resin layer is lowered, and the peeling becomes unstable. Can not do. Therefore, easy-openability and sealing performance can be satisfied by setting the content of the ethylene-polar vinyl compound copolymer to 5 to 50 wt%.
[0015]
The ethylene-polar vinyl compound copolymer of the cohesive failure resin layer is preferably an ethylene-acrylic acid copolymer or an ethylene-vinyl acetate copolymer.
By using an ethylene-acrylic acid copolymer or an ethylene-vinyl acetate copolymer as the ethylene-polar vinyl compound copolymer, it is possible to make it particularly excellent in cohesive failure.
[0016]
Furthermore, it is preferable to have a gas barrier layer on the side opposite to the cohesive fracture resin layer side of the base material layer.
Here, as the gas barrier layer, for example, materials such as polyamide, polyethylene terephthalate, ethylene-vinyl alcohol copolymer, and polyvinylidene chloride can be used.
By forming the gas barrier layer, it is possible to improve the oxidation resistance, i.e., storage stability, of the article to be packaged in the container.
[0017]
Of the present invention For retort food The easy-open packaging body includes any of the containers described above and a lid material that closes the opening of the container. For retort food The easy-open packaging body is characterized in that the lid material is heat-sealed on the outer peripheral side of the cut of the flange portion of the container.
Here, the lid member is preferably provided with a gas barrier property.
By heat-sealing the lid material on the outer peripheral side of the cut, the portion of the flange portion sealed by the lid material can be easily peeled off together with the lid material.
[0018]
At this time, the lid member of the flange portion of the container Above It is preferable that 0.5 mm or more from the notch is heat sealed to the outer peripheral side.
When the lid material is heat-sealed to the outer peripheral side by 0.5 mm or more from the notch of the flange portion of the container, For retort food When the internal pressure of the easy-packaging package increases, the sealed part between the lid and flange of Among them, stress concentrates on the inner peripheral side portion. Since almost no stress acts on the cut, it can be prevented that the non-cohesive fracture resin layer is peeled off from the cut by internal pressure, and the pressure resistance is excellent. For retort food It can be set as an easily openable package.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
[0020]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a multilayer sheet 1 used for forming the container 3 of the present embodiment. The multilayer sheet 1 includes a first base material layer 11, an adhesive layer 12, a gas barrier layer 13, an adhesive layer 14, a second base material layer 15, a cohesive fracture resin layer 16, and a non-cohesive failure. It has a seven-layer structure including a conductive resin layer 17.
[0021]
The first base material layer 11 and the second base material layer 15 are mainly composed of a polyolefin resin, for example, a polypropylene resin. The thickness dimension of each base material layer 11 and 15 is 100-2000 micrometers, Most preferably, it is 200-1000 micrometers.
As the adhesive layers 12 and 14, for example, an unsaturated carboxylic acid or a derivative-modified polyolefin resin thereof can be used.
As the gas barrier layer 13, it is preferable to use materials such as polyamide, polyethylene terephthalate, ethylene-vinyl alcohol copolymer, and polyvinylidene chloride. Among them, it is preferable to use ethylene-vinyl alcohol copolymer.
[0022]
The cohesive fracture resin layer 16 contains 50 to 95 wt% of a polypropylene resin and 5 to 50 wt% of an ethylene-polar vinyl compound copolymer. Especially, it is preferable to contain a polypropylene resin 60 to 95 wt% and an ethylene-polar vinyl compound copolymer 5 to 40 wt%.
As the ethylene-polar vinyl compound copolymer, it is preferable to use an ethylene-acrylic acid copolymer or an ethylene-vinyl acetate copolymer. Examples of the ethylene-acrylic acid copolymer include ethylene-acrylic acid copolymer (EAA), ethylene-methyl acrylate copolymer (EMA), ethylene-methacrylic acid copolymer (EMAA), and ethylene-methyl methacrylate copolymer. Well-known things, such as a polymer (EMMA), an ethylene-ethyl acrylate copolymer (EEA), an ethylene-ethyl acrylate-maleic anhydride copolymer (EEA-MAH), an ionomer resin, can be illustrated.
Examples of the polypropylene resin include homopolypropylene, random polypropylene, and block polypropylene.
The thickness dimension of the cohesive fracture resin layer 16 is preferably about 20 to 200 μm, particularly preferably 80 to 120 μm.
The non-cohesive breakable resin layer 17 contains a polypropylene resin having a melting point of 140 ° C. or higher. At this time, the polypropylene resin may be, for example, homopolypropylene or random polypropylene. The thickness dimension of the non-cohesive breakable resin layer 17 is preferably, for example, about 40 to 200 μm, and particularly preferably 80 to 120 μm.
[0023]
Such a multilayer sheet 1 is formed by a multilayer extrusion method using a T die. That is, five types of extruders corresponding to each layer 11 to 17 are used, and each layer 11 to 17 extruded from each extruder is merged and laminated by a special block provided immediately before entering the T die.
[0024]
Next, with reference to FIG. 2, the easy-open packaging body 2 which concerns on this invention is demonstrated.
The easy-open packaging body 2 includes a container 3 and a lid 4.
The container 3 includes a circular bottom surface 31 and a cylindrical side surface 33 which is integrally formed by rising from the bottom surface 31 and has an opening 32 at the upper portion. An extended ring-shaped flange portion 34 is integrally formed.
[0025]
As shown in FIG. 3, the container 3 is obtained by thermoforming the multilayer sheet 1 so that the non-cohesive breakable resin layer 17 is on the inner surface side of the container. Examples of a method for forming the container 3 include a method in which the multilayer sheet 1 is pre-stretched with a plug in a cavity formed in an outer shape of the container, and then plug assist molding is used to form a container by pressure forming or vacuum forming. .
An annular cut 35 is formed in the non-cohesive fracture resin layer 17 of the flange portion 34 of the container 3 so as to surround the opening 32. As shown in FIG. 4, the cut 35 has a V-shaped cross section, and the depth dimension thereof preferably does not reach the cohesive fracture resin layer 16.
[0026]
Returning to FIG. 3, the lid member 4 will be described. The lid 4 closes the opening 32 of the container 3 and has an outer diameter larger than the outer diameter of the flange portion 34 of the container 3. The lid member 4 includes a first PP (polypropylene) layer 41 made of polypropylene resin, an adhesive layer 42, a gas barrier layer 43, an adhesive layer 44, and a second PP layer 45. The lid 4 is in contact with the container 3 with the second PP layer 45 serving as a heat seal layer.
Here, the gas barrier layer 43 can be made of a material such as polyamide, polyethylene terephthalate, ethylene-vinyl alcohol copolymer, polyvinylidene chloride, as in the gas barrier layer 13 of the multilayer sheet 1.
The adhesive layer 42 can also be made of the same material as the adhesive layers 12 and 14 of the multilayer sheet 1.
[0027]
Such an easy-open packaging body 2 is obtained by heat-sealing the lid 4 to the flange portion 34 of the container 3 using an annular seal ring. The lid 4 is sealed to the outer peripheral side of 0.5 mm to 10 mm, particularly preferably 1 to 5 mm from the cut 35 of the container 3.
In opening the easy-open packaging body 2, if a force is applied in the direction in which the lid 4 is peeled off, cohesive failure occurs in the cohesive failure resin layer 16. Of the cohesive fracture resin layer 16 and the non-cohesive fracture resin layer 17, the outer peripheral side portion of the cut 35 heat-sealed to the lid member 4 is peeled off together with the lid member 4, whereby the easy-open packaging body 2 is formed. It will be opened.
[0028]
Therefore, according to this embodiment, the following effects can be produced.
A cut 35 is formed in the non-cohesive breakable resin layer 17, and the lid 4 is welded to the outer peripheral side of the cut 35, so that the cohesive breakable resin layer 16 that has caused cohesive failure at the time of opening, A portion welded to the lid member 4 in the non-cohesive breakable resin layer 17 can be peeled off together with the lid member 4. Therefore, easy-openability can be satisfied.
[0029]
Since the non-cohesive and destructible resin layer 17 is formed on the cohesive and destructible resin layer 16, by changing the resin used for the non-cohesive and destructible resin layer 17, can do. For example, when the container 3 having chemical resistance and heat resistance is desired, the non-cohesive fracture resin layer 17 may be formed of a chemical resistance and heat resistant resin. In this embodiment, since the polypropylene resin having a melting point of 140 ° C. or higher is used for the non-cohesive breakable resin layer 17, the container 3 having high heat resistance can be obtained.
In addition, since the non-cohesive fracture resin layer 17 may be changed according to the use of the container 3, the resin used for the cohesive fracture resin layer 16 is not limited to the use of the container 3. Can be widened.
[0030]
Further, since the non-cohesive breakable resin layer 17 is formed on the cohesive breakable resin layer 16, the odor of the ethylene-acrylic acid copolymer or ethylene-vinyl acetate copolymer of the cohesive breakable resin layer 16. Can be prevented.
Furthermore, in the case of a material that causes delamination, the delamination strength is likely to change due to thermal history, molding such as stretching, layer thickness, and the like. Therefore, it may be difficult to control the peel strength to be constant. On the other hand, in this embodiment, since peeling occurs by causing cohesive failure in the cohesive fracture resin layer 16, the peel strength is constant. Moreover, by preventing the interface between the cohesive fracture resin layer 16 and the second base material layer 15 from peeling, the peel strength can be further stabilized.
[0031]
Further, since the cuts 35 are formed in the non-cohesive breakable resin layer 17, the thickness dimension of the non-cohesive breakable resin layer 17 is increased to 40 to 200 μm as in this embodiment, or a high melting point, It is possible to use a resin with high strength and high rigidity.
Further, when the cut 35 is not formed in the non-cohesive breakable resin layer 17, it is necessary to perform peeling by cutting off the edge of the heat seal portion between the lid member 4 and the non-cohesive breakable resin layer 17. is there. In this case, it is necessary to reduce the thickness of the lid member 4 or to consider the material of the lid member 4. On the other hand, in this embodiment, since the notch 35 is formed in the non-cohesive fracture resin layer 17, it is not necessary to consider peeling due to edge breakage, and the thickness of the lid member 4 can be increased. is there.
[0032]
Moreover, since the ethylene-acrylic acid copolymer or the ethylene-vinyl acetate copolymer is used as the soft resin of the cohesive fracture resin layer 16, the cohesive peelability can be improved.
[0033]
When the ethylene-acrylic acid copolymer or the ethylene-vinyl acetate copolymer of the cohesive breakable resin layer 16 is less than 5 wt%, the opening strength becomes too high. Further, when the amount of the ethylene-acrylic acid copolymer or ethylene-vinyl acetate copolymer is more than 50 wt%, the adhesive strength between the second base material layer 15 and the cohesive fracture resin layer 16 is lowered. However, since peeling becomes unstable, smooth opening cannot be performed. Therefore, by setting the content of the ethylene-acrylic acid copolymer or the ethylene-vinyl acetate copolymer to 5 to 50 wt%, it is possible to satisfy the easy opening property and the sealing property of the container 3.
Moreover, since the container 3 has the gas barrier layer 13, the oxidation resistance of the filler in the container 3, that is, the storage stability can be improved.
[0034]
The lid 4 is heat-sealed from the notch 35 of the flange portion 34 of the container 3 to the outer peripheral side of 0.5 mm to 10 mm. When the internal pressure of the easy-open packaging body 2 increases, stress concentrates on the inner peripheral side portion of the seal portion between the lid member 4 and the flange portion 34. Since almost no stress acts on the cut 35, it is possible to prevent the non-cohesive breakable resin layer 17 from being peeled from the cut 35 due to internal pressure, and the easy-open packaging body 2 having excellent pressure resistance can be obtained.
[0035]
It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.
In the above embodiment, an ethylene-vinyl alcohol copolymer is used as the gas barrier layer 13. However, the present invention is not limited to this, and polyamide, polyethylene terephthalate, polyvinylidene chloride, or the like may be used.
However, if the gas barrier layer 13 is formed of an ethylene-vinyl alcohol copolymer, the moldability is good and the sealing property is higher.
[0036]
Furthermore, although the container 3 was provided with the gas barrier layer 13, if the to-be packaged object has oxidation resistance, it does not need to have the gas barrier layer 13. In this way, the container 3 can be made inexpensive.
Further, the ethylene-polar vinyl compound copolymer of the cohesive fracture resin layer 16 is an ethylene-acrylic acid copolymer or an ethylene-vinyl acetate copolymer. Copolymers and other soft resins can be used.
Further, it is not a soft resin such as an ethylene-polar vinyl compound copolymer, but an elastomer such as an olefin elastomer (density 900 kg / m between amorphous ethylene and an α-olefin such as propylene and butene). ^Three The following copolymers), styrene elastomers (styrene-butadiene block copolymers, styrene-butadiene random copolymers, etc.), hydrogenated products thereof and the like may be used.
[0037]
The cohesive fracture resin layer 16 contains 50 to 95 wt% polypropylene resin and 5 to 50 wt% ethylene-polar vinyl compound copolymer, but is not limited to this ratio.
The cohesive breakable resin layer 16 contains a polypropylene resin, but may contain other polyolefin resins. A non-cohesive and destructible resin layer is formed on the cohesive and destructible resin layer, and the cohesive and destructible resin layer is not a surface layer. Can be selected. For example, it may be replaced with a polypropylene resin instead of a polypropylene resin.
The polyolefin resin of the non-cohesive breakable resin layer 17 is a polypropylene resin having a melting point of 140 ° C. or higher. However, when heat resistance is not required, for example, polyethylene may be adopted.
[0038]
In the said embodiment, although the resin-made cover materials 4 were used, you may use the cover material which has not only this but metal stays, such as aluminum, a metal vapor deposition film, an inorganic vapor deposition film, etc. In the container 3 of the present invention, the notch 35 is formed in the non-cohesive breakable resin layer 17, and it is not necessary to consider peeling due to edge breakage, and thus such a lid material can be used.
[0039]
The lid 4 is heat-sealed to the outer peripheral side of 0.5 mm to 10 mm from the notch 35 of the flange portion 34 of the container 3, but is not limited to this range, and may be heat-sealed to the outer peripheral side from 10 mm. Good. Moreover, it may be less than 0.5 mm.
Moreover, in the said embodiment, although the thickness dimension of the non-cohesive fracture resin layer 17 was 40-200 micrometers, it is not restricted to this thickness dimension.
Furthermore, in the said embodiment, although the shape of the flange part 34 of the container 3 was made into the flat flange extended to the outer side horizontally with the surface to which the opening part 32 belongs, it extends to the outer side horizontally with the surface to which the opening part belongs, A skirt flange having a U-shaped cross section depending on the outermost edge or a curled flange may be used. In this case, it is possible to make a cut in the hanging portion of the flange portion.
[0040]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.
[Multilayer sheet 1]
The multilayer sheet 1 shown in the embodiment was formed by coextrusion molding.
(1) First base material layer 11
Raw material resin: Polypropylene (E-203GK, manufactured by Idemitsu Petrochemical Co., Ltd.)
Layer thickness: 200 μm
[0041]
(2) Adhesive layer 12
Raw material resin: Adhesive resin (Admer QF-500, manufactured by Mitsui Chemicals, Inc.)
Layer thickness: 20 μm
(3) Gas barrier layer 13
Raw material resin: ethylene-vinyl alcohol copolymer (Eval, Kuraray Co., Ltd. J-102B)
Layer thickness: 50 μm
[0042]
(4) Adhesive layer 14
Raw material resin: Adhesive resin (Admer QF-500, manufactured by Mitsui Chemicals, Inc.)
Layer thickness: 20 μm
(5) Second base material layer 15
Raw material resin: Polypropylene (E-203GK, manufactured by Idemitsu Petrochemical Co., Ltd.)
Layer thickness: 350 μm
[0043]
(6) Cohesive fracture resin layer 16
Raw material resin: Polypropylene (E-105GM, manufactured by Idemitsu Petrochemical Co., Ltd.) 70 wt%, ethylene / acrylic acid ester / maleic anhydride copolymer resin (EMA) manufactured by Nippon Polyolefin Co., Ltd., flexural modulus 80 MPa) 30 wt% % Blended resin
Melting point (measured by DSC method) 99 ° C
MFR (measured according to JIS K6760) 8 g / 10 min
Layer thickness: 200 μm
[0044]
(7) Non-cohesive fracture resin layer 17
Raw material resin: Random polypropylene
Melting point 145 ° C
Layer thickness: 40 μm
[0045]
[Container 3]
Using the multilayer sheet 1, a container 3 having a diameter of the opening 32 of 64 mm, a diameter of the bottom surface 31 of 50 mm, and a width of the flange 34 of 8 mm was obtained by plug-assisted pressure air thermoforming. An annular cut 35 was formed in the flange portion 34 of the container 3.
[0046]
[Cover 4]
The lid material 4 was molded by coextrusion molding.
(1) PP layer 41
Raw material resin: Random polypropylene
Layer thickness: 200 μm
(2) Adhesive layer 42
Raw material resin: Adhesive resin (Admer QF-500, manufactured by Mitsui Chemicals, Inc.)
Layer thickness: 30 μm
(3) Gas barrier layer 43
Raw material resin: ethylene-vinyl alcohol copolymer (Eval, Kuraray Co., Ltd. J-102B)
Layer thickness: 40 μm
(4) Adhesive layer 44
Raw material resin: Adhesive resin (Admer, manufactured by Mitsui Chemicals, Inc.)
Layer thickness: 30 μm
(5) PP layer 45
Raw material resin: Random polypropylene
Layer thickness: 40 μm
[0047]
[Easy opening packaging 2]
After filling the container 3 with jelly, the lid 4 was welded. Specifically, a first seal portion was formed at 190 ° C., 15 MPa, 1.5 seconds from the notch 35 of the flange portion 34 to the outer peripheral side of 2 mm using an annular seal ring having a width of 5 mm. Furthermore, the 2nd seal part was formed so that the center part of the width direction of a 1st seal part might be followed using the ring seal of width 2mm. The second seal portion has an overhanging seal portion protruding outward at a position corresponding to the back surface of the opening tab of the lid member 4.
Furthermore, the easy-open packaging body 2 obtained in this way was subjected to a retort treatment at 120 ° C. for 30 minutes.
[0048]
[Evaluation methods and results]
The peel strength and internal pressure strength of the easy-open packaging body 2 were measured.
The peel strength was measured by performing a 180 ° peel test (JISK 6854) using a test piece cut out with a width of 15 mm.
The internal pressure strength was measured by a method in which air was injected into the easy-open packaging body 2 and measured.
The peel strength before retorting of the easy-open packaging body 2 was 15 N / 15 mm, and the internal pressure strength was 0.05 MPa. Further, the peel strength after the retort treatment was 14 N / 15 mm, and the internal pressure strength was 0.05 MPa.
From the above, it was confirmed that the package was an ideal easy-open packaging body with low opening strength while maintaining sufficient internal pressure strength.
[0049]
Next, in order to confirm the effect of the present invention, the following comparative experiment was performed.
(Comparative example)
It is the same as that of an Example except the point which did not form the non-cohesive fracture resin layer 17 of a container.
[Evaluation methods and results]
The internal pressure strength and peel strength were measured by the same measurement method as in the examples.
In the comparative example, the peel strength before the retort treatment was 14 N / 15 mm, the internal pressure strength was 0.03 MPa, the peel strength after the retort treatment was 13 N / 15 mm, and the internal pressure strength was 0.03 MPa.
Thus, in the comparative example, it was revealed that the pressure resistance is low and sufficient sealing performance cannot be obtained.
[0050]
【The invention's effect】
According to the present invention, it has a high sealing performance and an easy-opening property, and can satisfy the performance according to the application. The Containers that can be selected and used and For retort food There exists an effect that an easy-open packaging body can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a multilayer sheet according to an embodiment of the present invention.
FIG. 2 is a perspective view showing the easy-open packaging body of the embodiment.
FIG. 3 is a cross-sectional view of the easy-open packaging body.
FIG. 4 is a cross-sectional view showing a main part of the container.
[Explanation of symbols]
1 Multi-layer sheet
2 Easy-open packaging
3 containers
4 Lid
13 Gas barrier layer
15 Base material layer
16 Cohesive fracture resin layer
17 Non-cohesive fracture resin layer
32 opening
34 Flange
35 depth of cut

Claims (7)

A container having a bottom surface and a side surface which is integrally formed by rising from the bottom surface and has an opening at the top, and a flange portion extending outward is integrally formed on the periphery of the opening,
A base material layer , a cohesive failure resin layer formed on the base material layer, containing a polyolefin resin and a soft resin or elastomer, and having a layer thickness of 20 μm or more and 200 μm or less, and the cohesive failure resin layer And a non-cohesive and destructible resin layer containing a polyolefin resin and having a layer thickness of 40 μm to 200 μm ,
The non-cohesive breakable resin layer is located on the inner surface side of the container,
An annular cut is formed in the non-cohesive fracture resin layer of the flange portion. The container according to claim 1,
The base material layer is a polyolefin resin,
The cohesive failure resin layer has an ethylene-polar vinyl compound copolymer that is a soft resin,
The polyolefin resin of the non-cohesive fracture resin layer is a polypropylene resin having a melting point of 140 ° C. or higher. The container according to claim 2,
The cohesive failure resin layer contains 50 to 95 wt% of a polypropylene resin and 5 to 50 wt% of an ethylene-polar vinyl compound copolymer. The container according to claim 2 or 3,
The container, wherein the ethylene-polar vinyl compound copolymer of the cohesive failure resin layer is an ethylene-acrylic acid copolymer or an ethylene-vinyl acetate copolymer. In the container according to any one of claims 1 to 4,
A container having a gas barrier layer on the side opposite to the cohesive failure resin layer side of the base material layer. An easy-open packaging for retort food comprising the container according to any one of claims 1 to 5 and a lid member that closes the opening of the container,
An easily openable package for retort food , wherein the lid material is heat-sealed on the outer peripheral side of the cut of the flange portion of the container. In the easy-open packaging for retort food according to claim 6,
The cover material, retort food easily openable package, characterized in that it is heat-sealed to 0.5mm above the outer peripheral side from the notch of the flange portion of the container.

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