JP5237654B2 - Multi-layer sheet, container and package - Google Patents

Description

  The present invention relates to a multilayer sheet, a container formed using the multilayer sheet, and a package using the container.

Conventionally, metal cans are often used as containers for filling and sales manufacturers that handle processed marine products and desserts.
The advantages of metal cans are: (1) Large liquid, gas, and light blocking properties, long-term storage (more than one year), (2) Good heat and electrical conductivity, heating and cooling efficiency It is good, (3) it is strong and rigid, so that it can be loaded and transported in large quantities, and (4) it can be molded at high speed and high accuracy at room temperature.

On the other hand, the disadvantages of metal cans are: (1) the specific gravity is large and heavy, making it difficult to transport and handle; (2) the metal reacts with the contents and external moisture; (3) The container shape is constant (for example, a cylindrical shape), the consumer is bored, (4) the contents are not visible at all, and the consumer may be anxious.
In addition to these problems, manufacturers who are turning to demetalization are spreading with an emphasis on recent environmental considerations.
For example, Patent Document 1 discloses a technique for improving a sealing property by providing a gas barrier layer on a laminate made of a resin and covering an end portion of the gas barrier layer.

JP 2000-25731 A

However, in Patent Document 1, although the sealing performance is somewhat improved, an oxygen barrier property that can achieve a substitute for a metal can is not realized.
Therefore, an object of the present invention is to provide a multilayer sheet, a container, and a package that have an oxygen barrier property comparable to that of a metal can and that have easy-openability, sealing properties, and heat resistance.

The multilayer sheet of the present invention is a multilayer sheet including a base material layer and an outermost layer laminated on one surface side of the base material layer, and the base material layer includes a first layer It is formed of at least three layers including a polyolefin layer, a barrier layer, and a second polyolefin layer in this order, and the outermost layer is a moisture absorbing adhesive layer provided on the side in contact with the base material layer, the moisture absorbing adhesive layer The base material layer is formed of at least three layers including a barrier layer provided on the side opposite to the base material layer, and a polyolefin layer provided on the barrier layer on the side opposite to the moisture absorbing adhesive layer. Talc is added to the first polyolefin layer and the second polyolefin layer of the layer .

The multilayer sheet of the present invention is formed of a base material layer and an outermost layer, and when this multilayer sheet is used as a container, the base material layer is formed so as to be positioned on the contents side. The base material layer is formed of at least three layers including a first polyolefin layer, a barrier layer, and a second polyolefin layer in this order . Further, the outermost layer is formed of at least three layers, and is formed such that a moisture absorbing adhesive layer is formed on the side in contact with the base material layer, a barrier layer is formed on the outer side of the moisture absorbing adhesive layer, and a polyolefin layer is formed on the outer side of the barrier layer. Is done. Further, talc is added to the first polyolefin layer and the second polyolefin layer of the base material layer. In addition, between these layers, the layer which has another function, for example, the layer which has fragrance retention property, chemical resistance, light-shielding property, UV cut property, etc., may be provided.
According to this invention, since the moisture-absorbing adhesive layer is provided on the side that contacts the outermost base material layer, moisture entering from the outside is absorbed by the moisture-absorbing adhesive layer in the boil / retort heat treatment. Reaching the material layer can be prevented.
Further, the barrier layer recovers the barrier performance by releasing moisture over time after moisture absorption in the boil / retort heat treatment. Therefore, the barrier performance of the barrier layer is quickly recovered by providing the barrier layer outside the moisture-absorbing adhesive layer.
As described above, a multilayer sheet having excellent oxygen barrier properties can be provided.
Talc works to physically block the entry of oxygen and water molecules. Therefore, by adding talc to the base material layer, oxygen barrier properties are improved, and moisture can be prevented from entering the base material layer.
Further, the rigidity of the multilayer sheet can be increased, and a container comparable to that of a metal can can be formed.

Barriers layers may preferably be provided as a base layer and the outermost layer of the intermediate layer, when the multilayer sheet with the container, it is preferable that the center of the base layer is provided on the outer side. Thereby, when a notch (cut) is processed in the container, the barrier layer can be prevented from being broken.
According to this invention, since the barrier layer is provided on each of the base material layer and the outermost layer, high oxygen barrier properties can be exhibited.

In the multilayer sheet of the present invention, it is preferable that a moisture-absorbing adhesive layer is provided on the outermost layer in contact with the base material layer.
According to this invention, since the moisture-absorbing adhesive layer is provided on the side that contacts the outermost base material layer, moisture entering from the outside is absorbed by the moisture-absorbing adhesive layer in the boil / retort heat treatment. Prevents reaching the barrier layer of the material layer. Therefore, it is possible to prevent a decrease in oxygen barrier properties due to moisture absorption by the barrier layer.
Therefore, the oxygen barrier property of the multilayer sheet can be further improved.

In the multilayer sheet of the present invention, it is preferable that a moisture absorbing adhesive layer is provided between the polyolefin layer and the barrier layer.
In the present invention, the barrier layer is sandwiched between the moisture-absorbing adhesive layers. If it is such a structure, the water | moisture content permeating from the outside will be absorbed by the water | moisture-content absorption adhesive layer, and it can prevent that a water | moisture content reaches | attains a barrier layer. That is, the oxygen barrier property of the barrier layer can be further improved.

The barrier layer in the multilayer sheet of the present invention is preferably formed of metaxylenediamine (MXD) nylon or ethylene / vinyl alcohol copolymer (EVOH).
According to this invention, since MXD nylon or EVOH is used as the barrier layer, a multilayer sheet excellent in oxygen barrier properties can be provided.

In the multilayer sheet of the present invention, a release layer is preferably laminated on the other surface side of the base material layer.
The adhesive strength between the release layer and the base material layer is made smaller than the adhesive strength by heat sealing between the container formed from the multilayer sheet and the lid. Thereby, when opening a cover material, it can be made to delaminate between a peeling layer and a base material layer. Therefore, it is excellent in easy-openability and the peeled surface can be made beautiful.
Moreover, since the heat seal part of a container and a cover material can be adhere | attached firmly, it is excellent also in sealing performance.

In the multilayer sheet of the present invention, the outermost layer is preferably a lamination film.
Since the outermost layer can be separately manufactured as a lamination film, the manufacturing process can be simplified.

The container of this invention is a container which has a flange part for adhere | attaching a cover material, Comprising: The multilayer sheet in any one of Claim 1-8 is shape | molded, It is characterized by the above-mentioned.
According to this invention, since the above-mentioned multilayer sheet is used, a container that can exhibit the same effect can be provided.

The package of the present invention is a package comprising the container according to claim 9 and a lid material that closes the opening of the container, wherein the lid material is bonded to a flange portion of the container. And
According to this invention, since the multilayer sheet and the container described above are used, it is possible to provide a package that can achieve the same effect.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, a first embodiment of the present invention will be described based on FIG. 1 and FIG.
[First Embodiment]
(I) Configuration of multilayer sheet 1A:
FIG. 1 is a cross-sectional view showing a multilayer sheet 1A according to the first embodiment of the present invention.
The multilayer sheet 1A is a base material layer comprising an outermost layer 11 having a polyolefin layer 111, a barrier layer 112, and a moisture absorbing adhesive layer 113, a first polyolefin layer 121, a barrier layer 122, and a second polyolefin layer 123. 12 and a release layer 13.

(I-1) Configuration of outermost layer 11:
The outermost layer 11 is a layer formed using a lamination film, and has a three-layer structure including a polyolefin layer 111, a barrier layer 112, and a moisture absorbing adhesive layer 113.
Examples of the resin that can be used for the polyolefin layer 111 include polypropylene and polyethylene.

  The barrier layer 112 is a layer having gas barrier properties, and examples of the raw material include ethylene / vinyl alcohol copolymer (EVOH), metaxylenediamine (MXD) nylon, and the like. When EVOH is used as the barrier layer 112, it is preferably formed with a thickness of 4% or more and 20% or less with respect to the total thickness of the multilayer sheet 1A. More preferably, the thickness is 8% or more and 15% or less with respect to the total thickness of the multilayer sheet 1A. In this case, if the thickness of the barrier layer 112 is less than 4% of the total thickness, long-term storage becomes impossible due to insufficient barrier performance. On the other hand, if the thickness of the barrier layer 112 is larger than 20% of the total thickness, it becomes unfavorable due to poor stretching during container molding.

When MXD nylon is used as the barrier layer 112, it is preferably formed with a thickness of 4% or more and 10% or less with respect to the layer thickness of the multilayer sheet 1A. More preferably, the thickness is 5% or more and 9% or less with respect to the thickness of the multilayer sheet 1A. In this case, if the thickness of the barrier layer 112 is less than 4% of the total thickness, long-term storage becomes impossible due to insufficient barrier performance. It is. Moreover, when the thickness of the barrier layer 112 is larger than 10% with respect to the total thickness, it becomes unfavorable due to poor stretching during container molding.
In this embodiment, MXD nylon is used for the barrier layer 112 of the outermost layer 11.

  The moisture-absorbing adhesive layer 113 is a layer that forms a surface in contact with the base material layer 12, absorbs moisture, and has a function as an adhesive. For example, a “water vapor barrier admer” manufactured by Mitsui Chemicals, Inc. is used can do. The moisture-absorbing adhesive layer 113 preferably has a thickness of 5 μm to 300 μm, more preferably 10 μm to 120 μm.

  The outermost layer 11 having such a three-layer structure is laminated. Specifically, known methods such as dry lamination, heat lamination, and extrusion lamination can be used.

(I-2) Configuration of the base material layer 12:
The base material layer 12 has a three-layer configuration including a first polyolefin layer 121, a barrier layer 122, and a second polyolefin layer 123.
Examples of the resin constituting the first polyolefin layer 121 and the second polyolefin layer 123 include HDPE (high density polyethylene), L-LDPE (low density polyethylene), LDPE (low density polyethylene), and HPP (homopolypropylene). , BPP (block polypropylene), RPP (random polypropylene), PET (polyethylene terephthalate), PBT (polybutylene terephthalate), maleic anhydride-modified PP, styrene-isoprene copolymer, modified polyester thermoplastic elastomer, EVA (ethylene-) Vinyl acetate copolymer), ethylene-propylene copolymer, and the like, and mixtures thereof. The resin used for the first polyolefin layer 121 and the second polyolefin layer 123 may be the same type of resin or a different type of resin.

In addition, the resin used for the first polyolefin layer 121 or the second polyolefin layer 123 may contain talc. Talc is a master batch raw material of hydrous magnesium silicate, and specifically, “S-U3” manufactured by Shinwa Plastic Co., Ltd., “MP465-2” manufactured by Calp Industry Co., Ltd., and the like can be used.
The barrier layer 122 is a layer having gas barrier properties like the barrier layer 112 described above, and examples of the raw material include EVOH and MXD nylon. The thickness of the barrier layer 122 is also the same as that of the barrier layer 112 described above. In the present embodiment, EVOH is used as the barrier layer 122 of the base material layer 12.
If the raw material of the barrier layer 122, the first polyolefin layer 121 and the second polyolefin layer 123 is the same resin, the barrier layer 122 and the first polyolefin layer 121, and the barrier layer 122 and the second polyolefin layer are used. Since it is excellent in adhesive strength with 123, it is preferable.

(I-3) Configuration of release layer 13:
The release layer 13 is laminated so as to be peelable from the base material layer 12. Alternatively, the release layer 13 itself may cause cohesive failure. In any case, when a peel test is performed after firmly bonding another film to the release layer 13, the peel strength is preferably 25 N / 15 mm or less (JIS K 6854). Thus, it can use suitably as multilayer sheet 1A for shape | molding the container for packaging bodies mentioned later that it is low peel strength.

Examples of the resin constituting the release layer 13 include HDPE, L-LDPE, LDPE, HPP, BPP, RPP, PET, PBT, ethylene maleic anhydride methyl acrylate copolymer, and a mixture of this copolymer and polyolefin. Etc. Further, when utilizing cohesive failure of the release layer constituting resin as the release mechanism, it is preferable to use a soft resin or elastomer having an elastic modulus of 200 MPa or less, particularly 150 MPa or less. Examples of the soft resin include an ethylene-polar vinyl compound copolymer. Examples of the elastomer include olefin elastomer, styrene elastomer, and hydrogenated products thereof. In this embodiment, HDPE is used.
The thickness of the release layer 13 is preferably 30 to 120 μm when an annular cut described later is provided on the outer surface of the flange portion, and is preferably 5 to 40 μm when no cut is provided.

  When providing the cut, if the thickness of the release layer 13 is less than 30 μm, it becomes difficult to process the depth of the cut in the release layer 13. If the thickness of the release layer 13 exceeds 120 μm, the thickness after the container is formed, particularly the thickness of the flange portion, becomes too thick, making it difficult to apply as a thin container. In the case where no notch is provided, if the thickness of the release layer 13 is less than 5 μm, the internal pressure resistance may deteriorate after the container is sealed with a lid. If the thickness of the release layer 13 exceeds 30 μm, one of the merits in the case of not providing the cut (providing easy opening while achieving thinning of the container) may be impaired.

  When the peeling between the base material layer 12 and the peeling layer 13 is used as a peeling mechanism, the adhesive strength (peeling strength) between the base material layer 12 and the peeling layer 13 is selected by appropriately selecting the type of each constituent resin. Can be controlled. For example, when the sealant of the lid material described later is polypropylene, it is preferable that the release layer 13 is made of random polypropylene, and the base material layer 12 is made of a mixture of polypropylene and polyethylene (the ratio of polyethylene is increased). When the sealant of the lid is polyethylene such as linear low density polyethylene (LLDPE), the release layer 13 is made of polyethylene, and the base layer 12 is made of a mixture of polypropylene and polyethylene (polypropylene). The ratio is preferably increased). When it is desired to cause cohesive failure inside the release layer 13 or the base material layer 12, it is preferable to use a composition in which the above-mentioned elastomer is appropriately mixed as a raw material for the layer desired to be cohesive.

(I-4) Manufacturing method of multilayer sheet 1A:
First, the film-like outermost layer 11 manufactured by the above-described coextrusion molding method is slit into a predetermined width and wound up in a roll shape. And the multilayer sheet 1A is manufactured by extruding the base material layer 12 and the peeling layer 13 which were laminated | stacked on the film-like outermost layer 11 extended | stretched from the roll in the predetermined order from the extruder, and laminating | stacking in a molten state (extrusion). Lamination). In addition, it can also be carried out by coextrusion, thermal lamination, dry lamination or the like, and can also be carried out by combining these steps.
Then, the sheet thickness is adjusted by cooling and solidifying by a touch roll or an air knife method and simultaneously adjusting the take-up speed. Thereafter, the sheet solidified with a roll is passed through a slit (width reduction), a continuous thickness meter, and a foreign object detector, and then the sheet is wound into a roll with a large winder. Finally, the roll of the multilayer sheet having a specified length is packed with an aluminum film (moisture-proof) or kraft paper (foreign matter adhesion prevention) to obtain a final product.

(II) Configuration of package 2:
The package 2 will be described with reference to FIGS. 2 and 3. FIG. 2 is a perspective view of the package according to the first embodiment of the present invention, and FIG. 3 is a cross-sectional view of the main part of the package according to the first embodiment of the present invention.
The package 2 shown in FIG. 2 includes a container 3 that is thermoformed using the multilayer sheet 1A and a lid 4 that covers the opening of the container 3.
(II-1) Configuration of container 3:
The container 3 includes a recess 31 for storing an object to be packaged and a flange portion 32 formed on the opening periphery of the recess 31. The concave portion 31 is a bottomed cylindrical shape, and the flange portion 32 is a flat flange that extends outward from the opening of the concave portion 31 in the horizontal direction. The flange portion 32 is provided with an annular cut portion 33 in the vicinity of the opening of the main body of the container 3. The cut portion 33 penetrates the release layer 13 and reaches the base material layer 12.

(II-2) Configuration of lid member 4:
The lid member 4 has an outer diameter larger than the outer diameter of the flange portion 32 of the container 3. The cover 4 is composed of a multilayer structure having a transparent vapor-deposited PET film 41 having an oxygen barrier property and a biaxially stretched nylon film (ONy film) 42 as a front substrate and an L-LDPE film 43 as a sealant. A portion of the outer surface 32 (the surface of the release layer 13) located on the outer periphery from the annular notch 33 is firmly heat-sealed. In addition, it is preferable that the adhesive strength of this heat seal is larger than the adhesive strength of the peeling layer 13 and the base material layer 12.
When the end portion of the lid member 4 attached to the container 3 is pulled up by hand in this manner, the release layer 13 of the flange portion 32 and the lid member 4 are firmly bonded, so that the release layer has a relatively low adhesive strength. Peeling begins at the interface between the base material layer 13 and the base material layer 12, and the lid 4 is separated from the container 3 when it reaches the notch 33. In addition, you may be comprised so that a cohesive failure may arise in the peeling layer 13. FIG.
Here, when the package 2 is configured, it is preferable that the lid member 4 also has an oxygen barrier property comparable to that of the multilayer sheet 1A. For example, in addition to using a surface base material having an oxygen-barrier silica film such as a transparent vapor-deposited PET film, an EVOH layer or an aluminum foil may be used as an intermediate layer.

(II-3) Manufacturing method of package 2:
A method for manufacturing the package 2 of the present embodiment will be described.
First, as a method for forming the container 3, plug assist molding is considered in which the multilayer sheet 1A is pre-stretched with a plug into a cavity formed in the outer shape of the container, and then subjected to pressure forming, vacuum forming, or the like.
Specifically, the multilayer sheet 1A manufactured by the above-described method is sent between a concave mold (not shown), a flange presser and a plug, and in this state, the flange presser and the plug are moved to the mold side. The container 3 in which the concave portion 31 for storing P and the flange portion 32 are formed is manufactured.
Thereafter, a cutting blade (not shown) is pressed against the flange portion 32 of the container 3 so that the cutting portion 33 is formed in an annular shape.
And the lid | cover material 4 is mounted on the flange part 32 of the container 3 in which the content P was accommodated, and the outer peripheral side of the notch part 33 is heat-sealed. An annular seal portion (not shown) is formed between the flange portion 32 and the lid member 4. The heat sealing is performed by pressing a seal bar (not shown) from the top of the lid member 4 to the flange portion 32.

(III) Effects of the first embodiment:
Therefore, according to this embodiment, the following effects can be produced.
(1) The barrier layer 112 made of EVOH was provided on the outermost layer 11 of the multilayer sheet 1A, and the barrier layer 122 made of MXD nylon was provided on the base material layer 12.
Since the multilayer sheet 1A is provided with two barrier layers of the barrier layer 112 and the barrier layer 122, the multilayer sheet 1A is excellent in oxygen barrier properties. Therefore, the container 3 and the package 2 excellent in oxygen barrier properties can be provided. That is, contents such as food can be stored for a long time.

(2) In the present embodiment, the moisture absorbing adhesive layer 113 is provided on the outermost layer 11 on the base material layer 12 side, and the barrier layer 112 is further provided outside the moisture absorbing adhesive layer 113. The barrier property can be further improved.
In addition, by providing the moisture-absorbing adhesive layer 113, when the container made of this multi-layer sheet is retorted, it absorbs and blocks the moisture reaching the barrier layer to suppress the retort shock and has excellent water resistance. It can be.

(3) Furthermore, in this embodiment, since the first polyolefin layer 121 and the second polyolefin layer 123 of the base material layer 12 contain talc, a container having excellent rigidity can be provided.

(4) In this embodiment, the multilayer sheet 1A is provided with the release layer 13, and the adhesive strength between the release layer 13 and the base material layer 12 is made smaller than the adhesive strength between the release layer 13 and the lid material 4. Therefore, when the package 2 is opened, delamination is performed between the release layer 13 and the base material layer 12.
Therefore, since the space between the release layer 13 and the lid 4 is firmly heat-sealed, the sealing performance is excellent.

(5) Since the annular cut portion 33 is formed in the flange portion 32 of the container 3, the peeling of the release layer 13 is cut when the lid 4 heat-sealed in the container 3 is opened. When the part 33 is reached, the lid 4 and the container 3 are easily separated. That is, it is excellent in easy openability.

[Second Embodiment]
Except for the difference in the layer structure of the multilayer sheet, the structure is the same as that of the first embodiment, and a description thereof will be omitted.
(I) Configuration of multilayer sheet 1B:
FIG. 3 is a cross-sectional view showing a multilayer sheet 1B according to the second embodiment of the present invention.
The multilayer sheet 1 </ b> B includes an outermost layer 11 having a polyolefin layer 111, a barrier layer 112, and a moisture absorbing adhesive layer 113, a base material layer 12, and a release layer 13.

Since the outermost layer 11 and the release layer 13 have the same configuration as in the first embodiment, description thereof is omitted.
The base material layer 12 is a single layer and is formed of a resin such as polyolefin. Resins similar to those used in the first polyolefin layer 121 and the second polyolefin layer 123 of the first embodiment can be used.

(II) Effects of the second embodiment:
Therefore, according to 2nd embodiment, there can exist an effect similar to 1st embodiment.

[Third embodiment]
Except for the difference in the layer structure and the manufacturing method of the multilayer sheet, the structure is the same as that of the first embodiment, and a description thereof will be omitted.
(I) Configuration of multilayer sheet 1C:
FIG. 5 is a cross-sectional view showing a multilayer sheet 1C according to the third embodiment of the present invention.
The multilayer sheet 1 </ b> C includes an outermost layer 14 having a polyolefin layer 141, a first moisture absorbing adhesive layer 142, a barrier layer 143, and a second moisture absorbing adhesive layer 144, a base material layer 12, and a release layer 13. It is equipped with.

Since the base material layer 12 and the peeling layer 13 are the same structures as 1st embodiment, description is abbreviate | omitted. In addition, the base material layer 12 can be designed appropriately, such as having the same configuration as in the second embodiment.
The outermost layer 14 is the same as the outermost layer 11 of the first embodiment except that the first moisture-absorbing adhesive layer 142 is provided between the barrier layer 143 and the polyolefin layer 141.
As the first moisture absorbing adhesive layer 142 and the second moisture absorbing adhesive layer 144, the same materials as those used for the moisture absorbing adhesive layer 113 of the first embodiment can be used.

(II) Method for Producing Multilayer Sheet 1C In the third embodiment, the outermost layer 14 is not used as a lamination film, and is produced by extrusion using an extruder in the same manner as the base material layer 12 and the release layer 13. In addition, thermal lamination, dry lamination, or the like can be performed, and further, these can be performed in a stepwise combination.
The processing after extrusion is performed in the same manner as in the first embodiment to obtain a final product.

(III) Effects of the third embodiment:
Therefore, according to the third embodiment, the same effect as that of the first embodiment can be obtained, and the moisture absorbing adhesive layer (the first moisture absorbing adhesive layer 142 and the second moisture absorbing adhesive layer 142 on the both surfaces of the barrier layer 143). Since the moisture absorbing adhesive layer 144) is provided, it is possible to reliably prevent moisture from entering the barrier layer 143 from the outside, and to further improve the oxygen barrier property of the barrier layer 143.

[Modification]
The aspect described above shows one aspect of the present invention, and the present invention is not limited to the above-described embodiment, and within the scope of achieving the objects and effects of the present invention. Needless to say, the modifications and improvements are included in the contents of the present invention. In addition, the specific structure, shape, and the like when carrying out the present invention may be other structures, shapes, and the like as long as the objects and effects of the present invention can be achieved.

For example, in the first embodiment described above, the moisture absorbing adhesive layer 113 is provided on the base layer 12 side of the outermost layer 11, but the moisture absorbing adhesive layer 113 may not be provided. In this case, it is preferable to provide a polyolefin layer on the base layer 12 side of the outermost layer 11.
In the first embodiment, MXD nylon is used for the barrier layer 112 of the outermost layer 11 and EVOH is used for the barrier layer 122 of the base layer 12. However, EVOH is used for the barrier layer 112 of the outermost layer 11 and the barrier of the base layer 12. MXD nylon may be used for the layer 122. Further, EVOH may be used for both barrier layers, or MXD nylon may be used for both barrier layers.
Furthermore, in the first embodiment, the outermost layer 11 has a three-layer structure, but a two-layer structure including a barrier layer and a polyolefin layer may be used.

And in above-mentioned embodiment, although talc was contained in resin which forms the polyolefin layer which comprises the base material layer 12, it is good also as a structure which does not contain a talc.
A moisture absorbing adhesive layer may be provided on the front and back of the barrier layer 122. According to this, it is possible to further improve the oxygen barrier property.
Furthermore, in the above-described embodiment, an adhesive layer may be provided between the layers. Thereby, the adhesive strength between each layer further improves.

  In the embodiment described above, the container 3 is provided with one notch 33, but the annular second notch is provided at a position away from the notch 33 on the outer peripheral side of the notch 33. It may be provided. In this case, the easy-openability of the package 2 is further improved by heat-sealing between the cut portion 33 and the second cut portion.

  Moreover, you may shape | mold the multilayer sheet of the said embodiment so that an outermost layer may become a container inner surface. According to this, when the polyolefin layer of the outermost layer is heat-sealed with the lid material and opened, the polyolefin layer is agglomerated and peeled off.

  EXAMPLES Next, although an Example and a comparative example are given and this invention is demonstrated in more detail, this invention is not restrict | limited at all to description content, such as these Examples.

[Examples 1 to 3, Reference Examples 1 to 12 , Comparative Examples 1 to 5]
Multilayer sheets of Examples 1 to 3, Reference Examples 1 to 12 and Comparative Examples 1 to 5 were prepared with the layer configurations and materials shown in Table 1 to be described later, and containers and packaging bodies made of this multilayer sheet were prepared.
(1) Production of multilayer sheet Examples 1 to 3, Reference Examples 1 to 10 and Comparative Examples 1 to 5 produced multilayer sheets having the following layer structure.
(Peeling layer)
/ (Base material layer) (polyolefin layer A2 / polyolefin layer A1 / adhesive layer / barrier layer B / adhesive layer / polyolefin layer C1 / polyolefin layer C2)
/ (Outermost layer) (Polyolefin layer D / Barrier layer E / Polyolefin layer F)

For Reference Examples 11 and 12 , a multilayer sheet composed of a release layer and a base material layer among the above layers was produced.

  First, each layer was melt-extruded and molded with a dedicated extruder (Mitsubishi Heavy Industries, Ltd.) using the materials shown below. As the outermost layer, a layer obtained by performing dry lamination using the following materials at Taisei Lamic Co., Ltd. was used.

(Base material layer: Polyolefin layers A and C)
Polypropylene (“E105GM” “E100GV” “E154G” manufactured by Prime Polymer Co., Ltd.) and polyethylene (“HE30” manufactured by Nippon Polyethylene Co., Ltd. “engage 8200” manufactured by Dow Co., Ltd.) are mixed, and white M / B (manufactured by Tokyo Ink “ W190078 "). The blending ratio was PP: PE: white M / B = 80: 16: 4 by mass ratio.
When talc is contained, “S-U3” (trade name, manufactured by Shinwa Plastic Co., Ltd.), “MP465-2” (trade name, manufactured by Calp Kogyo Co., Ltd.), and the like are mixed. The compounding ratio in this case is PP: PE: white M / B: talc = 56: 10: 4: 30 by mass ratio.

(Barrier layers B and E)
Any of the resins shown below can be used.
EVOH (“SP-521B” manufactured by Kuraray Co., Ltd.), thickness: 12% with respect to the total thickness.
MXD nylon ("S7007" manufactured by Mitsubishi Gas Chemical Company), thickness: 6% of the total thickness.

(Outermost layer: Polyolefin layers D, F)
Resins similar to those used for the polyolefin layers A and B described above can be used.
In addition, when making the polyolefin layer D into a water | moisture-content absorption adhesive layer, water vapor | steam barrier adma (made by Mitsui Chemicals) is used.

(Adhesive layer)
“Modic P604V” (trade name, manufactured by Mitsubishi Chemical Corporation) was used as the adhesive layer.
In Reference Examples 11 and 12 , a vapor barrier adma (manufactured by Mitsui Chemicals), which is a moisture absorbing adhesive, was used as the adhesive layer.

Next, the multilayer sheet was laminated.
After laminating each layer in the order described above, it was widened with a T-type die (Mitsubishi Heavy Industries, Ltd.). And the film for lamination which comprises an outermost layer was inserted | pinched in parallel with the lower surface of the molten sheet extruded from the T type | mold die, the thermal lamination was implemented continuously, and the multilayer sheet was shape | molded.
After molding, the multilayer sheet was cooled and solidified by a touch roll or air knife method, and at the same time, the take-up speed was adjusted to adjust the thickness of the sheet.
The thickness of each layer was as follows.

(2) Manufacture of container After heating the multilayer sheet described above, it is introduced into a continuous vacuum / pressure forming machine (such as a CM forming machine manufactured by Sumitomo Heavy Industries, manufactured by iLLig, and manufactured by Morning Research Laboratories, etc.), and plug-assisted vacuum compressed air is introduced. And thermoformed into a container. And after forming the cyclic | annular cut | notch part (notch) in the flange part of the container, container punching was performed.

(3) Manufacture of packaging body As a cover material, the thing of the following multilayer structure was used, and it heat-sealed and sealed the flange part of the container, and created the packaging body.
Structure of lid material: Polyethylene terephthalate (PET) 12 μm / biaxially stretched nylon film (ONy) 15 μm / aluminum (Al) 7 μm / Mitsui Chemicals “Omak CPP sealant” 70 μm

<Evaluation of oxygen barrier properties>
The oxygen barrier property of the container was evaluated by the following procedure.
(1) A reducing solution (Pyrogirl / alkaline solution) was prepared in advance under an oxygen removal environment.
(2) The reducing solution of (1) was filled and sealed in the containers of Examples 1 to 3, Reference Examples 1 to 12, and Comparative Examples 1 to 5 in an oxygen-removing environment , and the entire container was retorted.
Here, the absorbance of the reducing solution was measured as a blank (reference).
(3) After retorting, store in a constant temperature and humidity chamber under accelerated conditions of 30 ° C. × 75% RH, measure the absorbance of the reducing solution in the container after a specified number of days, and measure the cumulative oxygen permeation rate Was measured.

The contents of evaluation are as follows.
◎: Very good ○: Excellent △: Good ×: Inferior (unusable)

(result)
The results of evaluation of Examples 1 to 3, Reference Examples 1 to 12, and Comparative Examples 1 to 5 are shown in Table 2 below.

Examples 1 to 3 and Reference Examples 1 to 12 had good oxygen barrier properties. Among these, Example 2 was particularly excellent in oxygen barrier properties.
On the other hand, Comparative Examples 1 to 5 were not practical due to insufficient oxygen barrier properties.

  The present invention can be widely used as packaging containers for various foods such as retort foods, medicines, cosmetics, and the like.

It is sectional drawing which shows the multilayer sheet which concerns on 1st embodiment of this invention. It is a perspective view which shows the package which concerns on 1st embodiment of this invention. It is principal part sectional drawing which shows the package which concerns on 1st embodiment of this invention. It is sectional drawing which shows the multilayer sheet which concerns on 2nd embodiment of this invention. It is sectional drawing which shows the multilayer sheet which concerns on 3rd embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A, 1B ... Multilayer sheet 2 ... Package 3 ... Container 31 ... Concave part 32 ... Flange part 33 ... Notch part 4 ... Cover material

Claims (11)

A multilayer sheet comprising a base material layer and an outermost layer laminated on one surface side of the base material layer,
The base material layer is formed of at least three layers including a first polyolefin layer, a barrier layer, and a second polyolefin layer in this order ,
The outermost layer is a moisture absorbing adhesive layer provided on the side in contact with the substrate layer, a barrier layer provided on the opposite side of the moisture absorbing adhesive layer from the substrate layer, and the barrier layer Formed of at least three layers including a polyolefin layer provided on the opposite side of the moisture-absorbing adhesive layer,
Talc is added to the first polyolefin layer and the second polyolefin layer of the base material layer. The multilayer sheet, wherein The multilayer sheet according to claim 1,
A multilayer sheet, wherein a moisture absorbing adhesive layer is provided between the polyolefin layer and the barrier layer. In the multilayer sheet according to claim 1 or 2,
The barrier layer is formed of metaxylenediamine (MXD) nylon or ethylene / vinyl alcohol copolymer (EVOH). In the multilayer sheet according to claim 3,
The barrier layer is formed of meta-xylenediamine (MXD) nylon.   In the multilayer sheet according to any one of claims 1 to 3,
  The barrier layer included in the base material layer is formed of an ethylene / vinyl alcohol copolymer (EVOH),
  The barrier layer included in the outermost layer is formed of an ethylene / vinyl alcohol copolymer (EVOH).
  A multilayer sheet characterized by that.   In the multilayer sheet according to any one of claims 1 to 3,
  The barrier layer included in the base material layer is formed of an ethylene / vinyl alcohol copolymer (EVOH),
  The barrier layer included in the outermost layer is formed of meta-xylenediamine (MXD) nylon.
  A multilayer sheet characterized by that.   In the multilayer sheet according to any one of claims 1 to 3,
  The barrier layer included in the base material layer is formed of meta-xylenediamine (MXD) nylon,
  The barrier layer included in the outermost layer is formed of an ethylene / vinyl alcohol copolymer (EVOH).
  A multilayer sheet characterized by that. In the multilayer sheet according to any one of claims 1 to 7 ,
A multilayer sheet, wherein a release layer is laminated on the other surface side of the base material layer. In the multilayer sheet according to any one of claims 1 to 8 ,
The outermost layer is a film for lamination. A container having a flange for bonding to a lid,
A container formed by molding the multilayer sheet according to any one of claims 1 to 9 . A package comprising the container according to claim 10 and a lid member that closes the opening of the container,
A packaging body, wherein the lid member is bonded to a flange portion of the container.

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