JP6218490B2 - Lid and manufacturing method thereof - Google Patents

Description

  The present invention relates to a lid for sealing an opening of a container, and more particularly to a lid for sealing an opening of a polypropylene container and a method for manufacturing the same.

Conventionally, containers for storing or moving foods, cosmetics, pharmaceuticals and the like have been used.
Generally, a container has an opening and is shaped so that an object can be put into the opening. Further, the opening of the container can be sealed with a lid.

In order to seal the opening of the container with the lid, for example, the peripheral edge of the opening of the container and at least a part of the lid can be combined. An example of this coupling means is a heat sealing method.
Moreover, in order to couple | bond a container and a cover material easily, a flange part may be provided in the periphery of the opening part of a container.

  The material of the container can be arbitrarily selected depending on the contents of the container. For example, the material of the container can be determined to have properties such as impermeability to the contents, resistance to the contents, low odor, non-solubility after molding, heat insulation, and barrier properties.

In recent years, at least the innermost layer of a resin-based container or a fiber molded product such as a paper cup has been coated with the resin.
Examples of the resin for forming or coating the container include polyethylene and polypropylene. In particular, in the field of packaging materials, attention has been paid to applying polypropylene to containers in order to give the containers properties such as shielding against odor, oxygen and water vapor, heat insulation, and heat resistance.

  As containers containing polypropylene (hereinafter referred to as “polypropylene containers”), for example, containers made of polypropylene, containers coated with a film mainly composed of polypropylene, and the like are known.

On the other hand, the material of the lid can also be selected depending on the type of resin contained or coated in the container.
In general, the lid is a laminate in which a plurality of layers such as a base material layer, a metal foil layer, and a sealant layer are laminated. In particular, as the innermost layer of the laminate, a sealant layer is disposed to seal the periphery of the opening of the container.

Conventional sealant layers include linear (linar) low density polyethylene (LLDPE) films. The LLDPE film can be laminated on the substrate by a sand lamination method.
However, a lid material in which a film sealant such as an LLDPE film is laminated by sand lamination has a drawback that curling of the lid material is difficult because the lid material is curled.

  Therefore, in order to determine the layer structure of the lid material, the adhesiveness between the resin used in the container and the sealant layer of the lid material and the adhesiveness between the sealant layer and other layers in the lid material should be considered. is there.

  For example, in patent document 1, it is an easily openable sealant film for a polypropylene container, and is adjacent to the resin layer (A) formed on the surface to be heat sealed to the adherend and the resin layer (A). The resin layer (A) is composed of 20 layers of high pressure method low density polyethylene (high pressure method LDPE) or ethylene copolymer with respect to 100 parts by mass of a mixed resin of polypropylene and polybutene-1. The resin layer (B) is formed of an ethylene / α-olefin copolymer, high density polyethylene or polypropylene polymerized using a single site catalyst. Sealant films have been proposed.

In order to form a packaging material using the sealant film described in Patent Document 1, it is easy to form a resin layer (A) and a resin layer (B) by coextrusion and inflation molding (extrusion temperature: 230 ° C.). An openable sealant film is obtained, and then a laminated film in which PET film / high pressure method LDPE layer / aluminum foil / adhesive layer / PET film are laminated in this order from the outside is used as the base material, and the inner PET film surface ( After the anchor coat is applied to the corona discharge treatment), the anchor coat surface and the resin layer (B) of the easy-open sealant film are opposed to each other, and the laminate is extruded using a high-pressure LDPE as an adhesive layer therebetween There is a description of a specific example in which a laminated body having the following layer structure is manufactured by laminating by a method (sand lamination method).
“PET film / high pressure method LDPE layer / aluminum foil / adhesive layer / PET film / high pressure method LDPE layer / resin layer (B) / resin layer (A)”

  In patent document 2, it is an easily openable packaging material formed with the laminated body which has a base material and a sealant layer, Comprising: As for a sealant layer, polybutene-1 is 33-82 with respect to 100 weight part of low density polyethylene (LDPE). It is formed by co-extrusion and laminating a first resin layer mixed in a weight part ratio and a second resin layer made of an ethylene / unsaturated carboxylic acid copolymer, and the second resin layer of the sealant layer is A packaging material is proposed that is laminated so as to face the substrate and has an average dispersion diameter of 1 to 10 μm in the thickness direction of the polybutene-1 film in the transverse (TD) cross section of the first resin layer. Yes.

  Specifically, the packaging material described in Patent Document 2 has a layer configuration of “paper / LDPE layer / aluminum foil layer / second resin layer / first resin layer”. The second resin layer concentrates the cohesive failure of the first resin layer in the vicinity of the interface between the first resin layer and the second resin layer, stabilizes the peel strength, and prevents the occurrence of stringing. Can do. Further, the presence of the second resin layer between the substrate and the first resin layer can suppress curling that occurs when the first resin layer is laminated on the substrate.

  In patent document 3, it is a lid | cover material for paper cups, Comprising: It has the layer structure of "printing base material layer / first adhesion auxiliary layer / barrier layer / second adhesion auxiliary layer / cushion layer / sealant layer", and As a resin constituting the cushion layer, a lid material that is LDPE having a melt flow rate (MFR) of 40 or less has been proposed.

Specifically, in the lid described in Patent Document 3, LDPE is used as the second adhesion auxiliary layer, LDPE is used as the cushion layer, and the second adhesion auxiliary layer and the cushion layer are coextruded laminates. Is done.
Moreover, the cover material described in Patent Document 3 is welded to a paper cup coated with polyethylene.

JP 2005-263277 A JP 2002-128128 A JP 2003-182759 A

  However, as described in Patent Document 1, a laminate in which a sealant film formed by a co-extrusion inflation method is used as a sealant layer, and the sealant layer and a base material layer are bonded together by a sand lamination method is a sealant. Since the layer is a film, it curls. Therefore, the laminate described in Patent Document 1 still has room for study from the viewpoint of suppressing the occurrence of curling.

  Furthermore, the sealant film described in Patent Document 1 contains polypropylene in the innermost layer in order to enable welding with a polypropylene container. As a result, when the laminate and the polypropylene container described in Patent Document 1 are sealed, the sealing temperature becomes high and the sealing time becomes long. Therefore, economics, safety and handling are sacrificed in the production of the lidded polypropylene container.

Moreover, as a manufacturing method of the cover material described in Patent Document 2, a sealant layer including a first resin layer and a second resin layer and a base material are laminated by a coextrusion laminating method, or a first Only the method of coextruding and laminating one resin layer and the second resin layer to form a sealant layer, and then dry laminating or extrusion laminating the sealant layer and the substrate is described.
In any case, since the first resin layer and the second resin layer have poor adhesion to each other, sufficient interlayer laminate strength cannot be obtained unless the co-extrusion method is used.

  Furthermore, the co-extrusion lamination of the sealant layer including the first resin layer and the second resin layer and the base material is achieved by a dedicated machine, and is widely distributed in the production of general films. Not achieved with laminating machines. A special machine is also required for coextrusion lamination of the sealant layer.

  Moreover, the cover material described in Patent Document 3 is a cover material for a paper cup coated with polyethylene, and is not suitable for a polypropylene container.

  Furthermore, as the method for producing the lid material described in Patent Document 3, only the coextrusion lamination of the second adhesion auxiliary layer and the cushion layer is described. There is still room for consideration.

  In Comparative Example 1 of Patent Document 3, a lid material having a layer configuration of “base material / aluminum foil / EMAA layer / sealant layer” and a container with a lid using the lid material are described. However, a container with a lid material having this layer structure can be achieved because the surface of the container is coated with polyethylene. Since a polypropylene container is not excellent in adhesiveness with the sealant layer described in Patent Document 3, it should be understood that the lid described in Comparative Example 1 cannot be bonded to the polypropylene container.

Therefore, this invention aims at providing the lid | cover material of following (1)-(3), and the container with a lid | cover using them:
(1) Cover material that can be manufactured by a single laminate method;
(2) A lid that reduces curling and can be accommodated in a single wafer; and (3) Can be sealed to a polypropylene container at a lower temperature (for example, about 140 ° C.) than a conventional lid, and has a wide range A lid that exhibits good openability while having good sealability over a temperature range (for example, about 140 ° C. to about 180 ° C.).

  In the lid material, the inventors make the laminate strength between the metal foil and the intermediate layer and the laminate strength between the intermediate layer and the sealant layer higher than the opening strength between the polypropylene container and the sealant layer of the lid material. Thus, the inventors have found that the above problems can be solved and completed the present invention. That is, the present invention is as follows:

[1] A lid for sealing the opening of the container,
Including a substrate, a metal foil, an intermediate layer and a sealant layer laminated in order,
The intermediate layer includes a first polyethylene and an ethylene / methacrylic acid copolymer or an ethylene / acrylic acid copolymer, and the sealant layer includes a second polyethylene and an α-olefin copolymer.
A lid for sealing the opening of the container.

  [2] The lid material according to [1], wherein the content of the acid component in the ethylene / methacrylic acid copolymer or the ethylene / acrylic acid copolymer is 4% by weight or less.

[3] a mixture of said first polyethylene and said ethylene-methacrylic acid copolymer or the ethylene-acrylic acid copolymer is, when measured in accordance with JIS K 7112, 895kg / ^{m 3} or more and 904 kg / ^{m 3} or less The lid according to [1] or [2], having a density of

  [4] Any of [1] to [3], wherein a weight ratio of the α-olefin copolymer to the mixture of the second polyethylene and the α-olefin copolymer is 0.01 or more and less than 0.7. The lid material according to claim 1.

  [5] The lid material according to any one of [1] to [4], wherein the α-olefin copolymer is a copolymer of ethylene and an alkene having 3 or 4 carbon atoms.

  [6] The lid according to any one of [1] to [5], wherein the first polyethylene and the second polyethylene are linear low-density polyethylene.

  [7] The lid material according to any one of [1] to [6] and the container are provided, and the sealant layer side of the lid material and the flange portion of the container are heat-sealed. , Containers with lids.

  [8] The lidded container according to [7], wherein the container is made of polypropylene, contains polypropylene, or is coated with polypropylene.

  [9] With the lid according to [7] or [8], obtained by heat-sealing the sealant layer side of the lid material and the flange portion of the container at a temperature of 140 ° C. or higher and 180 ° C. or lower. container.

[10] A first laminating step of laminating a metal foil on a substrate to obtain a first laminate;
Applying a mixture of polyethylene and ethylene / methacrylic acid copolymer or ethylene / acrylic acid copolymer to the metal foil side of the first laminate, forming an intermediate layer on the metal foil, Applying a mixture of polyethylene and α-olefin copolymer to the intermediate layer side of the second laminate, forming a sealant layer on the intermediate layer, and The manufacturing method of the cover material for sealing the opening part of a container including the 3rd lamination process of obtaining a laminated body.

  [11] The method according to [10], wherein the second laminating step and the third laminating step are each performed by a single laminating method.

  According to the present invention, the resin contained in the intermediate layer is excellent in adhesion to the metal foil, and the resin contained in the intermediate layer and the resin contained in the sealant layer are compatible. Can be manufactured.

  Further, according to the present invention, since the sealant layer may be an extruded resin layer, not a film, there is no step of sand laminating the film with the base material layer, no curling occurs when sand laminating, and as a laminate The cover material suitable for sheet storage can be manufactured.

  Furthermore, according to the present invention, the sealant layer containing polyethylene and an α-olefin copolymer has improved adhesion to polypropylene as compared to a sealant layer containing only LLDPE, and LLDPE is a conventional polypropylene sealant. Since the melting point is lower than that of the conventional sealing temperature, the sealing temperature of the lid and the polypropylene container can be made lower than that of the conventional sealing temperature, and the sealing temperature range in which good sealability can be obtained can be expanded from the conventional temperature range.

It is a schematic cross section of a lid material according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail.

  The present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist of the present invention.

<Cover material>
A lid | cover material is an element for sealing the opening part of a container.
A lidded container and a flange part of a container can be heat-sealed to obtain a container with a lid.

  As shown in FIG. 1, the lid member (1) includes a base material (2), a metal foil (3), an intermediate layer (4), and a sealant layer (5) that are sequentially laminated.

<Constituent elements of the lid>
Hereinafter, the “base material”, “metal foil”, “intermediate layer”, and “sealant layer” that are components of the lid member will be described.

<Base material>
The base material is an element that gives the lid member a predetermined strength or rigidity.

  In general, since the lid member is formed by punching a laminated body such as a sheet or a roll, the base material can have sufficient strength or rigidity to keep the laminated body in a predetermined form.

  Moreover, it is preferable that a base material provides predetermined | prescribed dead hold property or hardness to a cover material.

  Examples of the base material include paper, metal, resin, natural or synthetic fiber.

  The resin for forming the base material preferably contains polyester as a main component. As resin which has polyester as a main component, polyethylene terephthalate (PET) etc. are mentioned, for example.

  Examples of the paper for forming the base material include high-quality paper, coated paper, and art paper. If desired, the paper can be hardened by applying a varnish to the surface of the paper.

<Metal foil>
The metal foil is formed by stretching the metal until it is in the form of a foil.
Examples of the metal foil include an aluminum foil.

  By including the metal foil in the lid member, the hardness, gas barrier property or dead hold property of the lid member can be ensured.

<Intermediate layer>
The intermediate layer is a layer located between the metal foil and the sealant layer. As shown in FIG. 1, the intermediate layer (4) is located between the metal foil (3) and the sealant layer (5).

  The intermediate layer includes a first polyethylene and an ethylene / methacrylic acid copolymer or an ethylene / acrylic acid copolymer.

An intermediate | middle layer can be adhere | attached on metal foil by including the combination of specific resin as mentioned above. Further, as will be described later, since the sealant layer also includes polyethylene, the intermediate layer is compatible with the sealant layer and can be adhered to the sealant layer.
Therefore, the metal foil and the sealant layer can be bonded via the intermediate layer.

  For example, the higher the laminate strength between the metal foil and the intermediate layer, the better, but it is measured with an extrusion single laminator at a line speed of 100 m / min (MD direction), a screw speed of 80 rpm, and a die of 300 to 305 ° C. The proportion of ethylene / methacrylic acid copolymer or ethylene / acrylic acid copolymer in the intermediate layer (first polyethylene and ethylene / methacrylic acid copolymer or ethylene / acrylic acid copolymer) to improve laminate strength under the processing conditions of extrusion temperature If it is increased, surging tends to occur or the followability of the resin tends to deteriorate. Therefore, the present inventors adjust the blending ratio of the mixed resin of the intermediate layer, the surging does not occur, the followability of the resin is good, and the blending of the intermediate layer having a laminate strength that exhibits a function as a lid The ratio was found. The laminate strength at the blending ratio was in the range of 2.5 N / 15 mm to 3.1 N / 15 mm.

In general, “surging” refers to a phenomenon in which the extruded resin greatly shakes in the left-right direction and the width direction is not stable. The occurrence of “surging” causes thickness unevenness.
In general, “poor resin followability” refers to a phenomenon in which, when a resin is extruded, the resin does not flow smoothly and the resin flow is divided.

  The higher the laminate strength of the intermediate layer and the sealant layer, the better. However, in order to improve the laminate strength, the ethylene / methacrylic acid copolymer in the intermediate layer (first polyethylene and ethylene / methacrylic acid copolymer or ethylene / acrylic acid copolymer) is used. Alternatively, when the ratio of the ethylene / acrylic acid copolymer is increased, surging occurs or the followability of the resin tends to deteriorate. Therefore, the present inventors adjust the blending ratio of the mixed resin of the intermediate layer, the surging does not occur, the followability of the resin is good, and the blending of the intermediate layer having a laminate strength that exhibits a function as a lid The ratio was found. The laminate strength at the blending ratio was in the range of 3.0 N / 15 mm to 3.7 N / 15 mm.

  The first polyethylene will be described later.

Moreover, since the ethylene content increases as the content of the acid component in the ethylene / methacrylic acid copolymer or ethylene / acrylic acid copolymer is adjusted to 4% by weight or less, the first polyethylene and the ethylene / methacrylic acid copolymer or Compatibility with ethylene / acrylic acid copolymer is improved.
Therefore, when the content of the acid component in the ethylene / methacrylic acid copolymer or the ethylene / acrylic acid copolymer is 4% by weight or less, surging is prevented and the followability of the resin is prevented when the intermediate layer is formed by the extrusion method. Can be secured.

  In the present specification, the “acid component” refers to a structural unit derived from methacrylic acid or acrylic acid in an ethylene / methacrylic acid copolymer or ethylene / acrylic acid copolymer.

The intermediate layer is composed of a mixture of the first polyethylene and ethylene / methacrylic acid copolymer or ethylene / acrylic acid copolymer, and the blending ratio of the mixture is set so that surging does not occur during extrusion lamination and the followability of the resin can be secured. density when the adjustment is when measured in accordance with JIS K 7112, is preferably 895kg / ^{m 3} or more and is 904 kg / ^{m 3} or less.
Furthermore, for the same purpose, it is preferable that the melt flow rate (MFR) of the mixture of the first polyethylene and the ethylene / methacrylic acid copolymer or the ethylene / acrylic acid copolymer is closer to the MFR of the first polyethylene.
Specifically, the MFR of the mixture of the first polyethylene and the ethylene / methacrylic acid copolymer or ethylene / acrylic acid copolymer is preferably about 12 (g / 10 min) (190 ° C.).

<Sealant layer>
The sealant layer is a layer for heat-sealing the lid material to the container to be sealed with the lid material.

  The sealant layer includes a second polyethylene and an α-olefin copolymer. Since polyethylene and an α-olefin copolymer are compatible with each other, they are preferable for forming a sealant layer.

  As described above, since the intermediate layer also includes polyethylene, the sealant layer has compatibility with the intermediate layer and can be bonded to the intermediate layer.

  In addition, since the sealant layer includes the α-olefin copolymer, the adhesiveness to polypropylene is improved, so that the sealant layer side of the lid can be heat sealed to the polypropylene container.

  The second polyethylene will be described later.

An α-olefin copolymer is a copolymer containing an α-olefin as a copolymerization component.
The α-olefin may be an alkene having a carbon-carbon double bond at the α-position, that is, an alkene having a carbon-carbon double bond at the terminal, but is preferably an alkene having 3 or 4 carbon atoms.

  Moreover, in order to control the range of the sealing temperature of the lid and the polypropylene container, the α-olefin copolymer is preferably a copolymer of ethylene and an alkene having 3 or 4 carbon atoms, and is composed of ethylene and propylene or butene. More preferably, it is a copolymer.

  Further, in the lidded container having the lid material of the present invention, in order to ensure the openability and peelability of the lid, the weight ratio of the α-olefin copolymer to the mixture of the second polyethylene and the α-olefin copolymer is It is preferably about 0.01 or more. On the other hand, this weight ratio is preferably less than about 0.7 in order to suppress the stickiness of the resin for forming the sealant layer and facilitate the processing of the resin. Furthermore, in order to control the range of the sealing temperature between the lid and the polypropylene container, the weight ratio is more preferably about 0.3.

<Polyethylene>
In the present specification, the polyethylene contained in the intermediate layer is referred to as “first polyethylene”, and the polyethylene contained in the sealant layer is referred to as “second polyethylene”.
Examples of the first polyethylene or the second polyethylene include LDPE, LLDPE, and high density polyethylene (HDPE).

  In order to ensure the compatibility between the resin contained in the intermediate layer and the resin contained in the sealant layer and to improve the laminate strength of the intermediate layer and the sealant layer, both the first polyethylene and the second polyethylene are LLDPE. It is preferable that

<Method for producing lid material>
The lid for sealing the opening of the container can be manufactured by a method comprising the following steps:
A first laminating step of laminating a metal foil on a substrate to obtain a first laminate;
Applying a mixture of polyethylene and ethylene / methacrylic acid copolymer or ethylene / acrylic acid copolymer to the metal foil side of the first laminate, forming an intermediate layer on the metal foil, Applying a mixture of polyethylene and α-olefin copolymer to the intermediate layer side of the second laminate, forming a sealant layer on the intermediate layer, and A third lamination step for obtaining a laminate.

The first lamination process can be performed by, for example, sand lamination, dry lamination, or the like.
When the first laminating step is performed by dry lamination, the dry laminate adhesive is preferably a two-component urethane adhesive, and more preferably a combination of polyester polyol and aromatic isocyanate.

  The second laminating step can be performed by single laminating a mixture of polyethylene and ethylene / methacrylic acid copolymer or ethylene / acrylic acid copolymer on the metal foil side of the first laminate.

  In general, “single laminate” refers to extrusion lamination of one kind of resin composition on a certain base material.

  The third lamination step can be performed by single laminating a mixture of polyethylene and α-olefin copolymer on the intermediate layer side of the second laminate.

  The second lamination step and the third lamination step are each preferably performed by a single lamination method. In that case, in the second lamination step, the line speed in the flow direction (MD direction) is 100 m / min, the screw rotation speed is 80 rpm, and the extrusion temperature under the die is preferably 300 to 305 ° C. . Moreover, in a 3rd lamination process, it is preferable that a line speed (MD direction) is 110 m / min, screw rotation speed is 80 rpm, and the extrusion temperature under die | dye is 320-325 degreeC.

If desired, the manufacturing method of the lid member may include a punching step of punching the obtained third laminated body into a predetermined shape after the third stacking step to obtain a lid member.
The punching process is performed, for example, by cutting the third laminated body into a sheet form with a rotary cutter, forming a plurality of sheets with a cutting machine, and then individually punching the sheets into the shape of a lid with a punching device. Can be.

<Container>
A container is a container which has an opening part and can put an object in an opening part. Further, the opening of the container can be sealed with a lid.

  In consideration of properties such as shielding against odor, oxygen and water vapor, heat insulation, heat resistance and the like, the container is preferably made of polypropylene, containing polypropylene, or coated with polypropylene.

  The container may have, for example, a flange portion that is used to bond the lid member to the periphery of the opening of the container.

  The container can store contents such as solid, liquid, gas, and gel. For example, food items such as beverages, pot noodles, yakisoba, pasta, honey beans, kuzukiri, tokoten, apricot tofu; chemicals, cosmetics, detergents, fragrances, pharmaceuticals, etc .; gaseous substances such as air and oxygen in containers Can be stored.

<Container with lid>
The container with a lid is obtained by heat-sealing the periphery of the lid material and the container.
Specifically, it is preferable that the sealant layer side of the lid member and the flange portion of the container are heat sealed.

In order to prevent feathering, it is preferable to heat seal the sealant layer side of the lid material and the flange portion of the container at a temperature of 140 ° C. or higher and 230 ° C. or lower to form a lidded container.
In general, “feathering” means a phenomenon in which a resin derived from a lid material remains in a fibrous form on a peeled surface when the lid is peeled from a lidded container, and is also referred to as “string drawing”.

  Furthermore, in order to prevent the generation of blisters (bubbles), the sealing temperature range between the sealant layer side of the lid and the flange portion of the container is preferably 140 ° C. or higher and 230 ° C. or lower, and 140 ° C. or higher and 180 ° C. The following is more preferable.

  In embodiments of the present invention, when the lidded container is in the form of a cup, the preferred opening strength range for the lid is preferably from about 0.9 kg / cup to about 2.0 kg / cup.

  In the embodiment of the present invention, when the lidded container is in the form of a cup, the preferable peel strength range for the lid is preferably about 0.15 kg / cup to about 0.5 kg / cup.

  Further, in the embodiment of the present invention, curling can be reduced and the cover material can be adapted for sheet storage.

  Furthermore, in the embodiment of the present invention, the laminate strength between the metal foil and the intermediate layer and the laminate strength between the intermediate layer and the sealant layer are stronger than the opening strength between the polypropylene container and the sealant layer. When peeling, the peeling between the plurality of layers constituting the lid can be suppressed.

  EXAMPLES The present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to the examples.

Test for confirming extrudability of intermediate layer As shown in Table 1 below, the type of linear low density polyethylene (LLDPE), the type of ethylene / methacrylic acid copolymer (EMAA), and the blending ratio based on the mass of LLDPE and EMAA The resin compositions for intermediate layers of Reference Examples 1 to 19 were prepared from LLDPE and / or EMAA.

MFR of the resin composition for intermediate | middle layers of Reference Examples 1-19 was measured using the melt flow rate measuring apparatus (Tateyama Scientific Industrial Co., Ltd. make, model number: Melt indexer L248).
Moreover, the density of the resin composition for intermediate | middle layers of Reference Examples 1-19 was measured according to JISK7112 using the density measuring apparatus (Alpha Mirage Co., Ltd. make, model number: Electronic hydrometer MD-300S).
The MFR and density of the intermediate layer resin compositions of Reference Examples 1 to 19 are shown in Table 1 below.

  Reference Examples 1-19 under the processing conditions of 100 m / min line speed (MD direction), screw speed of 80 rpm, and extrusion temperature measured under a die of 300 to 305 ° C. or higher using an extrusion single laminator. The intermediate layer resin composition was extruded and visually observed.

  Specifically, the presence / absence of surging and the presence / absence of followability of the resin were observed. The observation results are shown in Table 1 below.

(Description of model numbers in Table 1)
SP00108C: LLDPE having an MFR of 12 (g / 10 min) and a density of 904 (kg / m ³ ) (“Evolu P [SP00108C]” manufactured by Prime Polymer Co., Ltd.)
SP1071C: LLDPE having an MFR of 10 (g / 10 min) and a density of 911 (kg / m ³ ) (“Evolue [SP1071C]” manufactured by Prime Polymer Co., Ltd.)
AN4228C: EMAA containing 4% by weight of acid component (“Nucrel [AN4228C]” manufactured by Mitsui DuPont Polychemical Co., Ltd.)
N0908C: EMAA containing 9% by weight of acid component (“Nucrel [N0908C]” manufactured by Mitsui DuPont Polychemical Co., Ltd.)
N1108C: EMAA containing 11% by weight of acid component (“Nucrel [N1108C]” manufactured by Mitsui DuPont Polychemical Co., Ltd.)

From Table 1, it can be seen that the resin composition that achieves good extrusion without surging at a blending ratio of LLDPE: EMAA = 7: 3 is a combination of LLDPE (SP00108C) and EMAA (AN4228C).
In addition, since the MFR values of SP00108C and AN4228C are close to each other, it is considered that the mixture of both is less likely to cause surging.

  Further, from Table 1, it is considered that EMAA with a small amount of acid component (4% by weight) contains a large amount of ethylene component, so that it is easily compatible with LLDPE. Therefore, it is considered that the surging phenomenon occurs when EMAA containing a large amount of acid component (9% by weight or 11% by weight) is used, but the surging phenomenon does not occur when EMAA containing a small amount of acid component (4% by weight) is used.

Measurement of laminate strength between metal foil and intermediate layer As shown in Table 2 below, the compounding ratio based on the mass of LLDPE and EMAA was determined, and the intermediate of Reference Examples 20 to 28 from LLDPE and / or EMAA A layer resin composition was prepared.

Reference Examples 20-28 under processing conditions of 100 m / min line speed (MD direction), screw speed of 80 rpm, and extrusion temperature measured under a die of 300-305 ° C. or higher using an extrusion single laminator. The intermediate layer resin composition was extruded and laminated to the aluminum foil (model number: 1N30 manufactured by Toyo Aluminum Chiba Co., Ltd.) side of the first laminate obtained by laminating the aluminum foil on the base material to produce a laminate having a width of 788 mm. did.
In addition, during extrusion lamination, the extruded resin was visually observed to check for surging and resin follow-up. The observation results are shown in Table 2 below.

  70% by mass of LLDPE (“Evolue P [SP00108C]” manufactured by Prime Polymer Co., Ltd.) and 30% by mass of α-olefin copolymer (“Tuffmer [A-1070S]” manufactured by Mitsui Chemicals, Inc.) are mixed to form a sealant layer. Resin composition A was obtained.

  Resin composition A for sealant layer under processing conditions of 110 m / min line speed (MD direction), screw rotation speed of 80 rpm, and extrusion temperature measured under a die of 300 ° C. or higher using an extrusion single laminator Was extruded into an intermediate layer to obtain a sealant layer B.

  The obtained laminate was cut to a width of 15 mm, and using a tensile tester (manufactured by Toyo Seiki Seisakusho, Model No .: Strograph VES1D), the laminate strength between the aluminum foil of the section and the intermediate layer according to JIS K6854-3 Was measured. The measurement results are shown in Table 2 below.

(Description of model numbers in Table 2)
SP00108C: LLDPE having an MFR of 12 (g / 10 min) and a density of 904 (kg / m ³ ) (“Evolu P [SP00108C]” manufactured by Prime Polymer Co., Ltd.)
AN4228C: EMAA containing 4% by weight of acid component (“Nucrel [AN4228C]” manufactured by Mitsui DuPont Polychemical Co., Ltd.)

Measurement of laminate strength between intermediate layer and sealant layer <When changing the composition of the intermediate layer using the same sealant layer>
As shown in Table 3 below, the mass ratio of LLDPE and EMAA was determined, and the resin compositions for intermediate layers of Reference Examples 29 to 37 were prepared from LLDPE and / or EMAA.

  Using an extruded single laminator, under the processing conditions of 100 m / min line speed (MD direction), screw speed of 80 rpm, and extrusion temperature measured under a die of 300-305 ° C., each of Reference Examples 29-37 The intermediate layer resin composition was extruded and laminated to the aluminum foil (model number: 1N30 manufactured by Toyo Aluminum Chiba Co., Ltd.) side of the first laminate obtained by laminating the aluminum foil on the base material to produce a laminate having a width of 788 mm. .

  70% by mass of LLDPE (“Evolue P [SP00108C]” manufactured by Prime Polymer Co., Ltd.) and 30% by mass of α-olefin copolymer (“Tuffmer [A-1070S]” manufactured by Mitsui Chemicals, Inc.) are mixed to form a sealant layer. Resin composition A was obtained.

  Resin composition for sealant layer under processing conditions of 110 m / min line speed (MD direction), screw speed of 80 rpm, and extrusion temperature measured under a die of 320-325 ° C. using an extruded single laminator A was extruded into the intermediate layer to obtain a sealant layer B.

  The obtained laminate was cut to a width of 15 mm, and using a tensile tester (manufactured by Toyo Seiki Seisakusho, model number: Strograph VES1D), the laminate strength between the intermediate layer and the sealant layer according to JIS K6854-3 Was measured. The measurement results are shown in Table 3 below.

(Description of model numbers in Table 3)
SP00108C: LLDPE having an MFR of 12 (g / 10 min) and a density of 904 (kg / m ³ ) (“Evolu P [SP00108C]” manufactured by Prime Polymer Co., Ltd.)
AN4228C: EMAA containing 4% by weight of acid component (“Nucrel [AN4228C]” manufactured by Mitsui DuPont Polychemical Co., Ltd.)

  It should be understood that “Unable to peel” in Table 3 indicates a good observation result.

<When changing the composition of the sealant layer using the same intermediate layer>
70% by mass of LLDPE (“Evolue P [SP00108C]” manufactured by Prime Polymer Co., Ltd.) and 30% by mass of EMAA (“Nucleel [AN4228C]” manufactured by Mitsui DuPont Polychemical Co., Ltd.) are mixed to obtain a resin composition for the intermediate layer Product C was obtained.

  Using an extruded single laminator, a resin composition for an intermediate layer under processing conditions of a line speed (MD direction) of 100 m / min, a screw speed of 80 rpm, and an extrusion temperature measured under a die of 300 to 305 ° C. C was extruded to the aluminum foil layer side of the first laminate in which the aluminum foil was laminated on the base material to obtain an intermediate layer D.

  As shown in Table 4 below, the type of α-olefin copolymer and the mass ratio of LLDPE and α-olefin copolymer were determined, and the resin for the sealant layer of Reference Examples 38 to 46 was obtained from LLDPE and / or α-olefin copolymer. A composition was prepared.

  Using the extruded single laminator, under the processing conditions of a line speed of 110 m / min (MD direction), a screw speed of 80 rpm, and an extrusion temperature measured under a die of 320 to 325 ° C., each of Reference Examples 38 to 46 Each of the resin compositions for the sealant layer was extruded and laminated on the intermediate layer D to prepare a laminate having a width of 788 mm.

  The obtained laminate was cut to a width of 15 mm, and using a tensile tester (manufactured by Toyo Seiki Seisakusho, model number: Strograph VES1D), the laminate strength between the intermediate layer and the sealant layer according to JIS K6854-3 Was measured. The measurement results of the laminate strength and the situation of the resin composition for the sealant layer at the time of extrusion are shown in Table 4 below.

(Description of model numbers in Table 4)
SP00108C: LLDPE having an MFR of 12 (g / 10 min) and a density of 904 (kg / m ³ ) (“Evolu P [SP00108C]” manufactured by Prime Polymer Co., Ltd.)
A-1070S: α-olefin copolymer (“Tuffmer [A-1070S]” manufactured by Mitsui Chemicals, Inc.)
P-0480: α-olefin copolymer (“Tafmer [P-0480]” manufactured by Mitsui Chemicals, Inc.)

  In Tables 2 to 4, in order for the lid material to be recognized as “good”, the laminate strength between the aluminum foil and the intermediate layer and the laminate strength between the intermediate layer and the sealant layer are both 2.5. It should be understood that it is required to be (N / 15 mm) or more.

  Moreover, since the stickiness of the resin composition for sealant layers is suppressed when the content rate of the alpha-olefin copolymer in the resin composition for sealant layers is less than about 70 mass% from Table 4, the resin composition for sealant layers is suppressed. It can also be seen that it becomes easier to process.

Production of lid material and lidded container, and peeling test of lid material [Example 1]
In view of the results shown in Tables 1-4, the following materials were prepared:
Paper: Basis weight 80 g / m ² Made by Daio Paper Co., Ltd. (model number: Ryuo Coat 80 g / m ² )
PET film: ASTOLOL POLYESTER FILM made by KOLON Co., Ltd.
PE: manufactured by Tosoh Corporation (model number: Petrocene 205)
Aluminum foil: Toyo Aluminum Chiba Co., Ltd. (model number: 1N30)
Adhesive: manufactured by DIC Corporation (model number: main agent LX-500 / curing agent KW-75)
Intermediate layer resin composition: mixture of LLDPE (70% by mass) and EMAA (30% by mass) Sealant layer resin composition: mixture of LLDPE (70% by mass) and α-olefin copolymer (30% by mass) LLDPE: Stock Made by company Prime Polymer (model number: Evolue P [SP00108C])
EMAA: Mitsui DuPont Polychemical Co., Ltd. (model number: Nucrel [AN4228C])
α-olefin copolymer: manufactured by Mitsui Chemicals, Inc. (model number: Toughmer [A-1070S])
Container: Paper cup with polypropylene sheets laminated on the inner surface

<Production of lid material>
Using a laminator, an adhesive was applied to the PET film, and aluminum foil was dry-laminated to produce a laminate a.

  Using a laminator, PE was extruded and laminated between the paper and the PET film side of the laminate a to produce a laminate b.

  Aluminum foil of laminate b under processing conditions of 100 m / min line speed (MD direction), screw speed of 80 rpm, and extrusion temperature measured under a 300-305 ° C die using an extruded single laminator On the side, the intermediate layer resin composition was extruded and laminated (back lamination) to prepare a laminate c.

  Intermediate layer of laminate c under processing conditions of 110 m / min line speed (MD direction), screw speed of 80 rpm, and extrusion temperature measured under a die of 320-325 ° C. using an extruded single laminator On the side, the resin composition for the sealant layer was extruded and laminated (back lamination) to produce a laminate d.

  The obtained laminate d was cut into a sheet with a rotary cutter, and was cut into sheets with a cutter. Then, the sheet | seat was pierced in the shape of a cover material with the individual punching apparatus, and the cover material was obtained.

The obtained cover material has a layer structure of “paper (80) / PE (18) / PET (8) // aluminum foil (6.5) / intermediate layer (25) / sealant layer (25)”. It was.
In the above layer structure, “/” represents an extruded laminate, “//” represents a dry laminate, and a numerical value in parentheses represents a thickness (μm).

<Production of container with lid>
Using a heat seal tester, heat seal the sealant layer side of the obtained lid material and the flange part of the container at a seal bar temperature of about 140 ° C. to about 230 ° C. as shown in Table 5 below. A container with a lid was obtained.

<Confirmation of blister>
The heat-sealed part of the obtained container with a lid was observed visually, and the presence or absence of blisters was evaluated according to the following criteria. The evaluation of blisters is shown in Table 5 below.
(Blister evaluation criteria)
○: Blister generation is not visually confirmed.
Δ: Blister generation is visually confirmed.

<Peel test>
Using a measuring stand, a tensile jig, and a tensile tester, a peel test was performed on each of the containers with lids obtained at the seal bar temperatures shown in Table 5 below, and the unsealing strength (kg / cup) and peel strength (kg / Cup) and the peeled portion of the lidded container was visually observed, and the presence or absence of feathering was evaluated according to the following criteria. The results of the peel test are shown in Table 5 below.

(Feathering evaluation criteria)
○: The occurrence of feathering is not visually confirmed.
X: The occurrence of feathering is visually confirmed.

  In addition, the unsealing strength (kg / cup) and peel strength (kg / cup) in Table 5 represent average values of five measurements.

[Examples 2 to 8]
<Production of lid material>
As shown in the columns of Examples 2 to 8 in Table 6, the mixing ratio of LLDPE and α-olefin copolymer was changed, and / or “Tafmer [P-0480]” manufactured by Mitsui Chemicals, Inc. was used as the α-olefin copolymer. A cover material was obtained in the same manner as in Example 1 except that was used.

<Production of container with lid>
Using a heat seal tester, the sealant layer side of the obtained lid material and the flange portion of the container were heat sealed at a seal bar temperature of about 160 ° C. to obtain a container with a lid.
In the same manner as in Example 1, a blister evaluation, a peel test, and a feathering evaluation of a container with a lid were performed. The results are shown in Table 6 below.

[Comparative Example 1]
<Production of lid material>
As shown in the column of Comparative Example 1 in Table 6, as in Example 1 except that a sealant layer was obtained using only LLDPE (“Evolue P [SP00108C]” manufactured by Prime Polymer Co., Ltd.). A lid was obtained.

<Production of container with lid>
Using a heat seal tester, the sealant layer side of the obtained lid material and the flange portion of the container were heat sealed at a seal bar temperature of about 160 ° C. to obtain a container with a lid.
In the same manner as in Example 1, a blister evaluation, a peel test, and a feathering evaluation of a container with a lid were performed. The results are shown in Table 6 below.

  The present invention can be used for manufacturing a lid for sealing a container having an opening.

1 Lid material 2 Base material 3 Metal foil 4 Intermediate layer 5 Sealant layer

Claims (11)

A lid for sealing the opening of the container,
Including a substrate, a metal foil, an intermediate layer and a sealant layer laminated in order,
The intermediate layer includes a linear low density polyethylene and an ethylene / methacrylic acid copolymer or an ethylene / acrylic acid copolymer, and the sealant layer includes a linear low density polyethylene and an ethylene / propylene copolymer or an ethylene / 1-butene copolymer . ,
A lid for sealing the opening of the container.   The lid material according to claim 1, wherein the content of the acid component in the ethylene / methacrylic acid copolymer or the ethylene / acrylic acid copolymer is 4% by weight or less. Mixture of the Riniya low-density polyethylene and the ethylene-methacrylic acid copolymer or the ethylene-acrylic acid copolymer, when measured in accordance with JIS K 7112, a density of 895kg / ^{m 3} or more and 904 kg / ^{m 3} or less The lid material according to claim 1 or 2, comprising: The weight ratio of the ethylene-propylene copolymer or the ethylene-1-butene polymer to a mixture of the Riniya low-density polyethylene and the ethylene-propylene copolymer or the ethylene-1-butene polymer, 0.01 or more and less than 0.7 The cover material according to any one of claims 1 to 3, wherein A container with a lid, comprising the lid material according to any one of claims 1 to 4 and the container, wherein the sealant layer side of the lid material and a flange portion of the container are heat-sealed. The container with a lid according to claim 5 , wherein the container is made of polypropylene, contains polypropylene, or is coated with polypropylene. The container with a lid according to claim 5 or 6 , which is obtained by heat-sealing the sealant layer side of the lid material and the flange portion of the container at a temperature of 140 ° C or higher and 180 ° C or lower. A first laminating step of laminating a metal foil on a substrate to obtain a first laminate;
Applying a mixture of linear low density polyethylene and ethylene / methacrylic acid copolymer or ethylene / acrylic acid copolymer to the metal foil side of the first laminate to form an intermediate layer on the metal foil, Applying a mixture of linear low density polyethylene and ethylene / propylene copolymer or ethylene / 1-butene copolymer to the intermediate layer side of the second laminate; The manufacturing method of the cover material for sealing the opening part of a container including the 3rd lamination process which forms a sealant layer on a layer and obtains a 3rd laminated body. The method according to claim 8 , wherein the second laminating step and the third laminating step are each performed by a single laminating method. The method according to claim 8 or 9, wherein the content of the acid component in the ethylene / methacrylic acid copolymer or the ethylene / acrylic acid copolymer is 4% by weight or less. When the mixture of the linear low density polyethylene and the ethylene / methacrylic acid copolymer or the ethylene / acrylic acid copolymer is measured according to JIS K 7112, 895 kg / m ³ And 904kg / m ³ 11. A method according to any one of claims 8 to 10 having the following density.

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