JP6984276B2 - Insulated double container - Google Patents

Description

The present invention relates to a heat insulating double container.

So-called paper cups having various forms have been developed and proposed for filling and packaging various liquid foods and drinks such as alcoholic beverages, fruit juices, soft drinks, dairy beverages, liquid seasonings, and the like. For example, a heat-insulating double container having a double-structured body of a paper cup to provide heat-insulating properties has been developed and proposed so that the contents can be easily held even at high temperatures (see, for example, Patent Document 1).

In recent years, there has been an increasing need to put the contents packaged in such a heat-insulated double container into a microwave oven together with the heat-insulated double container and cook them.

Japanese Unexamined Patent Publication No. 2003-112718

Although the current heat-insulated double container is manufactured assuming that the contents are hot, it is not supposed to be used for microwave cooking. Therefore, the current heat-insulated double container is used. When cooked in a microwave oven using it, in some cases, the adhesive layer constituting the heat-insulating double container may be deteriorated by heat, and the original function may not be fulfilled, such as deterioration of adhesiveness and barrier property. rice field.

In addition, when a heat-insulating double container containing contents containing an oil component is cooked in a microwave oven, heat is locally applied, and the layers constituting the heat-insulating double container, such as a seal layer and a barrier layer, are melted and pinholes are formed. May occur.

The present invention has been made in such a situation, and provides a heat-insulated double container that does not deteriorate in function even when used in a situation exposed to a higher temperature than before, such as microwave cooking. This is the main issue.

The present invention for solving the above problems includes a cup-shaped inner container including a tubular cup body member and a bottom member that seals the bottom of the tubular cup body member, and the cup of the cup-shaped inner container. A heat insulating double container comprising an exterior sleeve that covers the body member so as to form a heat insulating space between the outer surface of the body member, and the cup body member and the bottom member are both composed of at least paper. It is composed of a laminated body in which a base material layer, an adhesive layer, a barrier layer, and a seal layer are laminated, and the adhesive layer is composed of an epoxy group-containing compound, a silane group-containing compound, a carboxylic acid group-containing compound, and a carboxylic acid group-containing compound. It is a resin composition containing 1 or 2 or more selected from the group consisting of an acid anhydride-containing compound.

In the above invention, the thickness of the adhesive layer may be 15 μm or more and 50 μm or less.

Further, in the above invention, the barrier layer may be one in which an inorganic oxide-deposited film or a metal-deposited film is laminated on one surface of a resin film.

Further, in the above invention, the seal layer in either or both of the laminated body constituting the cup body member and the laminated body constituting the bottom member has a density of 0.900 or more and 0.925 or less. It may contain an ethylene-α / olefin copolymer resin polymerized using a single-site catalyst, having a melt index of 1.0 or more and 20.0 or less.

Further, in the above invention, a laminating layer may be provided between the barrier layer and the sealing layer.

Further, in the above invention, it is preferable that the melting point of the adhesive layer is higher than the melting point of the seal layer.

According to the heat-insulating double container of the present invention, an adhesive layer made of a resin composition containing a predetermined compound is used, so that even when exposed to a higher temperature than before, such as cooking in a microwave oven, the adhesive layer is used. The original function is not deteriorated, and the occurrence of pinholes can be suppressed.

It is schematic cross-sectional view which shows the layer structure of the laminated body which comprises the cup body member and the bottom member of the cup type inner container of the heat insulating double container which concerns on embodiment of this invention. It is a schematic sectional drawing which shows the structure of the heat insulating double container which concerns on embodiment of this invention.

Hereinafter, the heat-insulated double container according to the embodiment of the present invention will be described in detail with reference to drawings and the like.

(Laminated body)
The heat-insulating double container according to the embodiment of the present invention includes a cup-shaped inner container including a cylindrical cup body member and a bottom member that seals the bottom of the tubular cup body member, and the cup-shaped inner container. An exterior sleeve that covers the body member so as to form a heat insulating space between the cup body member and the outer surface thereof is provided. Both the cup body member and the bottom member are composed of at least a laminated body in which a base material layer made of paper, an adhesive layer, a barrier layer, and a seal layer are laminated. First, the laminated body constituting the cup body member and the bottom member of the cup-shaped inner container will be described below.

FIG. 1 is a schematic cross-sectional view showing a layer structure of a laminated body constituting a cup body member and a bottom member of a cup-shaped inner container of a heat-insulating double container according to an embodiment of the present invention.

As shown in FIG. 1, in the laminate 10 constituting the cup body member and the bottom member, at least the base material layer 11 made of paper, the adhesive layer 12, the barrier layer 13, and the seal layer 14 are laminated in this order. Being done.

In the present specification, when the cup-shaped inner container is formed by using the laminated body 10, the side located on the outside of the cup-shaped inner container is referred to as the "outer surface side" and is located inside the cup-shaped inner container. The side to be used is referred to as the "inner surface side". In FIG. 1, the upper side is the “outer surface side” and the lower side is the “inner surface side”.

Hereinafter, each layer constituting the laminated body 10 will be described.

-Base material layer The base material layer 11 is made of paper. Since this paper is a basic material constituting a heat insulating container, it can be used to have shapeability, bending resistance, rigidity, waist, strength and the like. As the paper, for example, a bleached or unbleached paper base material which is a main strength material and has a strong size property, or various paper base materials such as pure white roll paper, kraft paper, paperboard, processed paper, and milk base paper are used. can do. The base material layer 11 may be a stack of a plurality of these papers. Further, the paper has a basis weight of ^{about 80 to 600 g / m 2} , preferably about ^{100 to 450 g / m 2} , and a thickness of about 110 to 860 μm, preferably about 140 to 640 μm can be used. ..

-Adhesive layer In the heat-insulating double container according to the embodiment of the present invention, the adhesive layer 12 constituting the laminate 10 is an epoxy group-containing compound, a silane group-containing compound, a carboxylic acid group-containing compound, and an acid anhydride. It is characterized in that it is a resin composition containing 1 or 2 or more selected from the group consisting of contained compounds.

A resin composition containing one or more selected from the group consisting of an epoxy group-containing compound, a silane group-containing compound, a carboxylic acid group-containing compound, and an acid anhydride-containing compound is used as the adhesive layer 12 to be described later. The adhesive strength with the barrier layer 13 can be improved, and as a result, wrinkles may occur in the base material layer 11 and the barrier layer 13 described later even when exposed to high temperatures such as microwave cooking. It is possible to suppress the occurrence of peeling.

The resin constituting such an adhesive layer 12 is not particularly limited, and is selected from the group consisting of an epoxy group-containing compound, a silane group-containing compound, a carboxylic acid group-containing compound, and an acid anhydride-containing compound. It can be appropriately selected from the resins capable of containing 1 or 2 or more, and for example, a polyethylene-based resin or a polypropylene-based resin may be used.

When a polyethylene-based resin is used as the resin constituting the adhesive layer 12, the density is preferably in the range of 920 to 970 kg / m ³ and more preferably in the range of ^{920 to 965 kg / m 3 because of its excellent heat insulating properties.} .. By setting the density of the resin constituting the adhesive layer 12 within the above range, pinholes, peeling and wrinkles of the barrier layer 13 can be effectively prevented even when the adhesive layer 12 is overheated by a microwave oven or the like. It can be suppressed. In addition, it is possible to suppress the generation of thermal pinholes during container molding. The melting point of the resin constituting the adhesive layer 12 is preferably higher than the melting point of the seal layer described later. For example, when exposed to a high temperature such as microwave cooking, wrinkles and peeling may occur between the barrier layer 13 and the barrier layer 13, which will be described later. Therefore, the melting point is preferably 100 ° C. or higher, preferably 110 ° C. or higher. More preferably, 120 ° C. or higher is particularly preferable.

As the resin constituting the adhesive layer 12, a polyethylene-based resin is preferable in consideration of the adhesiveness to the base material layer 11 and the barrier layer 13. Such a polyethylene-based resin may be an ethylene homopolymer, an ethylene / α-olefin copolymer, or a composition thereof, and the form of the molecular chain thereof may be linear and has a length of 6 or more carbon atoms. It may have a chain branch.

Examples of the ethylene homopolymer include medium- and low-pressure ethylene homopolymers and high-pressure low-density polyethylene. Medium / Low Pressure Method Ethylene homopolymers can be obtained by conventionally known medium / low pressure ion polymerization methods. Further, the high-pressure method low-density polyethylene can be obtained by a conventionally known high-pressure radical polymerization method.

Examples of the α-olefin used in the ethylene / α-olefin copolymer include propylene, 1-butene, 4-methyl-1-pentene, 3-methyl-1-butene, 1-pentene, 1-hexene and 1-hexene. , 1-octene, 1-nonen, 1-decene, 1-undecene, 1-dodecene and the like, and one or more of these can be used. The method for obtaining the ethylene / α-olefin copolymer is not particularly limited, and examples thereof include high / medium / low pressure ion polymerization methods using a Ziegler-Natta catalyst, a Philips catalyst, and a single-site catalyst. can. Such a copolymer can be conveniently selected from commercially available products.

Examples of the epoxy group-containing compound contained in the resin constituting the adhesive layer 12 include epoxidized vegetable oil (epoxidation of unsaturated double bonds of natural vegetable oil), glycidyl ether type, glycidyl amine type, and glycidyl ester type. Can be mentioned. Of these, epoxidized vegetable oil is more preferable from the viewpoint of safety when used as a food packaging material. For example, epoxidized soybean oil, epoxidized flaxseed oil, epoxidized olive oil, epoxidized safflower oil, epoxidized corn oil and the like are used. The content of such an epoxy group-containing compound is, for example, 0.01 to 10 parts by weight, preferably 0.01 to 5.0 parts by weight, based on 100 parts by weight of the resin constituting the adhesive layer 12. If it is less than 0.01 parts by weight, the adhesive strength with the barrier layer 13 becomes insufficient, and if it exceeds 10 parts by weight, it is not preferable because it causes blocking and particularly odor when used for food packaging.

As the silane group-containing compound contained in the resin constituting the adhesive layer 12, a silane oligomer is preferably used. More specifically, in order to improve the adhesiveness, a silane oligomer containing any one of an epoxy group, a mercapto group and an alkoxy group in the molecule, or several kinds thereof is desirable. The silane oligomer is blended in an amount of 0.01 to 10 parts by weight, preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the resin constituting the adhesive layer 12. If the blending amount of the silane oligomer is less than 0.01 parts by weight, the adhesive strength with the barrier layer 13 is insufficient, and if it exceeds 10 parts by weight, the molding process is inferior, which is not preferable.

As the carboxylic acid group-containing compound contained in the resin constituting the adhesive layer 12, ethylene-unsaturated carboxylic acid or a copolymer with an esterified product thereof can be used. More specifically, examples thereof include an ethylene-acrylic acid copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methacrylic acid copolymer, and an ethylene-methyl methacrylate copolymer. It is also possible to use an ionomer resin in which the molecules of ethylene-unsaturated carboxylic acid are crosslinked with metal ions.

As the acid anhydride-containing compound contained in the resin constituting the adhesive layer 12, maleic acid-modified polyolefin-based resins such as maleic acid-modified polyethylene-based resin and maleic acid-modified polypropylene-based resin are preferable, and maleic acid-modified polyethylene anhydride-modified polyethylene is preferable. Anhydrous maleic acid-modified polyolefin-based resin such as a based resin or a maleic anhydride-modified polypropylene-based resin is more preferable. The maleic acid-modified polyolefin-based resin is obtained by graft-polymerizing maleic acid on the polyolefin-based resin.

Further, the thickness of the adhesive layer 12 is not particularly limited, but is preferably 15 μm or more and 50 μm or less. By setting the thickness of the adhesive layer 12 within the above range, it is effective to generate heat pinholes during container molding and to generate pinholes and wrinkles even when overheated by a microwave oven or the like. Can be suppressed. If the thickness exceeds 50 μm, the entire laminated body becomes hard and may cause molding defects.

In addition to the above-mentioned various compounds, the resin constituting the adhesive layer 12 is generally used as a polyolefin resin such as an antioxidant, a light stabilizer, an antistatic agent, a lubricant, and an antiblocking agent, if necessary. The additive may be added as long as the object of the present invention is not impaired.

The method for forming the adhesive layer 12 is not particularly limited, and for example, an extrusion coat, a laminated film prepared in advance, dry lamination, or the like can be used.

Barrier layer The laminate 10 constituting the cup body member and the bottom member is provided with the barrier layer 13 on the inner surface side of the adhesive layer 12. By providing the barrier layer 13, it is possible to impart high airtightness to the cup body member and the bottom member.

Such a barrier layer 13 is not particularly limited as long as it can block a gas such as oxygen, but for example, as shown in FIG. 1, inorganic oxidation is performed on one surface of the resin film 13a. It is preferable that the material vapor deposition film 13b or the metal vapor deposition film 13b is laminated.

Examples of the resin film 13a constituting the barrier layer 13 include a film made of polyester, polyamide, polypropylene, polyethylene terephthalate, stretched nylon, and the like, which include an ethylene-vinyl alcohol copolymer, a polyamide, and polyvinylidene chloride. , Polyacronitrile and other layers formed of a resin exhibiting gas barrier properties may be laminated. The thickness is preferably, for example, about 6 to 25 μm.

On the other hand, examples of the inorganic oxide-deposited film 13b constituting the barrier layer 13 include a film made of silicon oxide, aluminum oxide, magnesium oxide, and the like.

Further, as the metal vapor deposition film 13b constituting the barrier layer 13, for example, an aluminum vapor deposition film or the like can be mentioned.

The thickness of such a barrier layer is not particularly limited, but is preferably about 6 to 200 μm as a whole, and more preferably about 9 to 100 μm.

In FIG. 1, the resin film 13a constituting the barrier layer 13 is located on the outer surface side, and the inorganic oxide vapor deposition film 13b and the metal vapor deposition film 13b constituting the barrier layer 13 are located on the inner surface side. The present invention is not limited to this, and the opposite, that is, the resin film 13a may be located on the inner surface side, and the inorganic oxide vapor deposition film 13b or the metal vapor deposition film 13b may be located on the outer surface side.

-Seal layer In the laminated body 10 constituting the cup body member and the bottom member, the seal layer 14 is provided on the inner surface side of the barrier layer 13.

The seal layer 14 forms a cup body member and a bottom member using the laminated body 10, and further heat-seals a predetermined portion when forming a cup-shaped inner container using these cup body members and the bottom member. It is a necessary layer for. Various conventionally known seal layers 14 can be used. Specifically, for example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear (linear) low-density polyethylene, ethylene-α / olefin copolymer polymerized using a single-site catalyst, polypropylene. , Ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene Acid-modified polyolefin resin obtained by modifying a polyolefin resin such as a polymer, methylpentene polymer, polybutene polymer, polyethylene or polypropylene with an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid and itaconic acid. , Polyvinyl acetate resin, poly (meth) acrylic resin, polyvinyl chloride resin, and other resins can be used, and these may be used alone or in admixture of two or more. You may use it.

Among the above, from the viewpoint of sealing properties, low-density polyethylene, medium-density polyethylene, linear (linear) low-density polyethylene, and ethylene-α-olefin copolymers polymerized using a single-site catalyst are more suitable. preferable. Of these, an ethylene-α / olefin copolymer polymerized using a single-site catalyst having excellent low-temperature sealing properties and hot tack properties is more preferable.

Regarding the physical characteristics of the ethylene-α / olefin copolymer polymerized using the single-site catalyst that can be suitably used in the present invention, the density is in ^{the range of 0.900 to 0.925 g / cm 3} , and preferably 0. Use one in the range of 905 to 0.915 g / cm ^3. If the density is ^{less than 0.900 g / cm 3} , the slipperiness is poor and paper jams occur with a feeder or the like, and in the process of punching into a blank shape, the cutability is poor, and the processing suitability in each process is poor. Therefore, it is not preferable. On the other hand, if the density ^{exceeds 0.925 g / cm 3} , the low temperature sealing property deteriorates, which is not preferable. The melt flow rate (MFR) is preferably in the range of 1.0 to 20 g / 10 minutes. When the melt flow rate (MFR) is less than 1.0, the fluidity of the resin is poor. Missing occurs. Further, when the melt flow rate (MFR) exceeds 20.0, the fluidity of the resin becomes high, and the resin cannot stay at the stepped portion of the wrinkles of the bottom member, and the seal is similarly removed. In addition, it is not preferable because it is inferior in hot tackiness.

Further, in the seal layer 14 in the present embodiment, one or more of the above resins are used and melt-extruded using an extruder or the like, for example, via an anchor coating agent layer or the like. By melt-extruding and laminating a melt-extruded resin layer together with the bonded layer 17, or by using one or more of the above resins, a resin film or sheet is manufactured in advance from this, and the resin film or sheet is manufactured. The sheet may be sandwich-laminated using a melt-extruded resin as the bonding layer 17. In order to prevent the occurrence of cracks in the vapor-filmed film of the inorganic oxide, one or more of the above resins are used, and a resin film or sheet is manufactured from this in advance as the bonded layer 17. It is more preferable to perform dry laminate lamination via an adhesive layer for lamination or the like.

As the melt-extruded resin of the bonded layer 17, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear (linear) low-density polyethylene, and ethylene-α polymerized using a single-site catalyst are used. -Olefin copolymer, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer Polymers, ethylene-propylene copolymers, methylpentene polymers, polybutene polymers, polyethylene or polypropylene and other polyolefin resins are used as unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid and itaconic acid. Resins such as acid-modified polyolefin resin, polyvinyl acetate-based resin, poly (meth) acrylic-based resin, etc. modified with the above can be used.

The thickness of the bonded layer 17 is preferably 15 μm to 40 μm. If it is less than 15 μm, the laminating strength tends to decrease, and if it exceeds 40 μm, the entire layer becomes hard and the moldability is inferior, which is not preferable.

On the other hand, as the adhesive for laminating the bonding layer 17, for example, a one-component or two-component curable or non-curable type vinyl-based, (meth) acrylic-based, polyamide-based, polyester-based, polyether-based, or polyurethane-based adhesive is used. , Epoxy-based, rubber-based, and other solvent-based, water-based, or emulsion-based adhesives for dry laminating can be used. Examples of the coating method for the dry laminating adhesive include a direct gravure roll coating method, a gravure roll coating method, a kiss coating method, a reverse roll coating method, a fonten method, and a transfer roll coating method, such as a paper substrate and a gas barrier. It can be applied to the bonded surface of a sex film, a sealant film, or the like.

The coating amount is preferably 0.1 to 10 g / m ² (dry state), and more preferably 1 to 5 ^{g / m 2} (dry state). If it is thinner than this, sufficient adhesive strength cannot be obtained, and
If it is too thick, there is a concern about residual solvent.

The seal layer 14 is not limited to a single layer or a co-pressing specification.

The thickness of the seal layer is preferably about 10 to 100 μm, preferably 10 to 60 μm. If it is less than 10 μm, the resin cannot be buried in the wrinkled portion generated when the paper is squeezed, and a sealing defect occurs, which is not preferable. If it exceeds 100 μm, the heat generated during extrusion causes cracks in the vapor-filmed layer to lower the barrier, or the entire layer becomes hard and the moldability is poor, which is not preferable.

-Other layers The laminated body 10 constituting the cup body member and the bottom member may include layers exhibiting various functions in addition to the above-mentioned layers. For example, it is preferable that the bonding layer 17 described above is included.

(Insulated double container)
Hereinafter, the heat-insulating double container according to the embodiment of the present invention using the laminated body 10 described above will be described.

FIG. 2 is a schematic cross-sectional view showing the configuration of the heat insulating double container according to the embodiment of the present invention.

As shown in FIG. 2, the heat insulating double container 100 according to the embodiment of the present invention includes a cup body member 21 made of the laminated body 10 described above and a bottom member 22 also made of the laminated body 10. It is composed of an inner cup container 20 and an outer sleeve 30 that covers the outside of the cup body member 21, and a heat insulating space 40 is formed between the cup body member 21 and the outer sleeve 30.

The heat-insulating double container 100 shown in FIG. 2 is merely an example, and is not limited to this shape. That is, the heat insulating double container 100 shown in FIG. 2 has an outer winding opening edge portion 23 in which the peripheral edge of the opening portion of the body member 21 is curled outward, but this may not be necessary. It may have another shape. Further, the heat insulating double container 100 shown in FIG. 2 has an inner winding opening edge portion 31 in which the bottom edge of the outer sleeve 30 is curled inward, but this may not be necessary. Further, it may have another shape. Further, the method of fixing the outer sleeve 30 to the inner cup container 20 is not limited, and a method other than the method shown in FIG. 2 may be used. Further, the heat insulating double container 100 shown in FIG. 2 may be a so-called flat bottom type heat insulating double container in which the foot portion 50 is provided on the bottom side but the foot portion 50 is not provided.

Further, the method for manufacturing the heat-insulated double container according to the embodiment of the present invention is not particularly limited, and a conventionally known manufacturing method can be appropriately selected.

The outer sleeve 30 constituting such a heat insulating double container 100 is not particularly limited, and conventionally known ones can be used. As the material of the exterior sleeve 30, for example, cardboard having a basis weight of 150 to 450 g / m ² or paperboard such as coated cardboard can be used. If the basis weight is ^{less than 150 g / m 2} , the rigidity becomes too low, and especially at high heat, the bending becomes too large to obtain a sufficient heat insulating effect, and if it ^{exceeds 450 g / m 2} , the rigidity becomes high. It is not preferable because the workability is lowered and the material cost is high. Further, a printing layer may be appropriately provided on the exterior sleeve 30. The print layer is not particularly limited, and various conventionally known print layers can be appropriately selected.

(Example 1)
As the barrier layer, a silica-deposited film having a silica-deposited film formed on one surface of the PET film and a base material layer composed of paper were prepared.

Next, while applying corona treatment to one surface of the base material layer, EMAA (AN4214C, density: 0.930, melting point: 105 ° C.) as an adhesive layer was extruded by 30 μm to the silica-deposited surface side of the barrier layer. Sandwich lamination was performed while applying in-line corona treatment.

Next, a two-component curable ester-based anchor coating agent (Takeda Pharmaceutical Co., Ltd. Takerack (registered trademark) A3210 / Takenate (registered trademark) A3075) was applied to the PET film surface side of the barrier layer with a gravure coater. An anchor coat layer was formed by drying through a drying oven.

Next, the above-mentioned anchor-coated layer was polymerized with a low-density polyethylene resin (density: 0.923, melt index (MI): 3.7, melting point: 111 ° C.) and a single-site catalyst. Using an olefin copolymer resin (density: 0.906, melt index (MI): 13.0, melting point: 103 ° C.), these are co-extruded to form a laminated layer 20 μm made of a low-density polyethylene resin. A 20 μm seal layer made of an ethylene-α / olefin copolymer resin polymerized using a single-site catalyst was formed to produce a laminate used for a body member and a bottom member.

Next, using the laminated body, a cylindrical cup body member and a bottom member that closes the lower end of the cup body member are formed, and the lower end portion of the cup body member is bent inward to form a peripheral edge portion of the bottom member. The cup contents are joined so as to cover the outer surface of the bottom member, and a plurality of concave and convex portions are alternately formed on the joint portion that covers the outer surface of the bottom member, and at least the convex portions are at the same height position. Manufactured a vessel.

On the other hand, an exterior paper having been subjected to predetermined printing was prepared and punched in a fan direction to obtain an exterior sleeve.

The lower edge peripheral end of the outer sleeve is folded inward to form a folded portion, the cup inner container is fitted into the outer sleeve from the bottom thereof, and the upper edge peripheral end of the outer sleeve is the upper edge of the cup inner container. It entered the gap inside the curl portion at the peripheral end, and the folded portion at the peripheral edge of the lower edge was aligned with the outer surface of the lower end portion of the body portion. Then, by fixing the lower end of the outer sleeve and the body of the container in the cup with an adhesive, a heat-insulating double container according to the first embodiment of the present invention was obtained.

(Example 2)
Other than extruding 20 μm of an acid anhydride-containing compound resin (density: 0.900, melting point: 120 ° C.) in forming the adhesive layer of the laminated body in the heat-insulating double container according to the first embodiment. The same conditions as in Example 1 were obtained, and a heat-insulated double container according to Example 2 was obtained.

(Example 3)
Other conditions, etc., except that an ionomer resin (density: 0.960, melting point: 126 ° C.) was extruded by 20 μm in forming the adhesive layer of the laminated body in the heat insulating double container according to the first embodiment. In the same manner as in Example 1, a heat-insulated double container according to Example 3 was obtained.

(Example 4)
In forming the adhesive layer of the laminated body in the heat-insulating double container according to Example 1, except that a medium-density polyethylene resin containing a silane oligomer (density: 0.933, melting point: 126 ° C.) was extruded by 20 μm. All other conditions and the like were the same as in Example 1, and a heat-insulated double container according to Example 4 was obtained.

(Example 5)
In forming the adhesive layer of the laminated body in the heat-insulating double container according to Example 1, except that a medium-density polyethylene resin containing a silane oligomer (density: 0.940, melting point: 126 ° C.) was extruded by 10 μm. All other conditions and the like were the same as in Example 1, and a heat-insulated double container according to Example 5 was obtained.

(Example 6)
In forming the adhesive layer of the laminated body in the heat-insulating double container according to Example 1, a silane oligomer-containing low-density polyethylene resin (density: 0.918, melting point: 103 ° C.) was extruded by 30 μm, except that it was extruded. All other conditions and the like were the same as in Example 1, and a heat-insulated double container according to Example 6 was obtained.

(Example 7)
In forming the adhesive layer of the laminated body in the heat-insulating double container according to Example 1, a medium-density polyethylene resin containing a silane oligomer (density: 0.933, melting point: 126 ° C.) was extruded by 30 μm and was low. A laminated body made of a single layer of a density polyethylene resin (density: 0.923, melt index (MI): 3.7, melting point: 111 ° C.) is formed to form a seal layer 40 μm, which is used for a body member and a bottom member. A heat-insulated double container according to Example 7 was obtained in the same manner as in Example 1 except that it was manufactured.

(Example 8)
As a barrier layer, the silica-deposited surface of the silica-deposited film on which the silica-deposited film is formed on one surface of the PET film and the polyethylene film B25μ (density: 0.923, melting point: 111 ° C.) are opposed to each other, and a two-component curable urethane is used. Dry laminating was carried out using a system adhesive. Further, a polyethylene film A25μ (density: 0.930, melting point: 123 ° C.) was opposed to the PET surface side of the silica vapor-deposited film, and similarly, dry laminating was carried out using a two-component curable urethane-based adhesive to carry out a dry lamination of the polyethylene film. A laminate of A / silica vapor-deposited PET / polyethylene film B was obtained.

Next, while applying corona treatment to one surface of the paper constituting the base material layer, a silane oligomer-containing medium-density polyethylene resin (density: 0.933, melting point: 126 ° C.) as an adhesive layer was extruded by 15 μm. Sandwich lamination was performed with the polyethylene film A side of the barrier layer facing each other.

Next, from the ethylene-α / olefin copolymer resin (density: 0.906, melt index (MI): 13.0, melting point: 103 ° C.) polymerized on the polyethylene film B side using a single-site catalyst. The heat-insulated double container according to Example 8 is provided in the same manner as in Example 1 except that the laminate used for the body member and the bottom member is manufactured by forming the seal layer 20 μm. Obtained.

(Comparative Example 1)
An ethylene-α / olefin copolymer resin (density: 0.888, melt index) polymerized using a single-site catalyst in forming the adhesive layer of the laminate in the heat-insulating double container according to Example 1. (MI): 20.0, melting point: 101 ° C.) was extruded by 30 μm, and all other conditions and the like were the same as in Example 1 to obtain a heat-insulated double container according to Comparative Example 1.

(Comparative Example 2)
An ethylene-α / olefin copolymer resin (density: 0.920, melt index) polymerized using a single-site catalyst in forming the adhesive layer of the laminate in the heat-insulating double container according to Example 1. (MI): 10.5, melting point: 109 ° C.) was extruded by 30 μm, and all other conditions and the like were the same as in Example 1 to obtain a heat-insulated double container according to Comparative Example 2.

(Evaluation of the appearance of the inner surface of the container and evaluation of the amount of pinholes generated)
Fried chicken was placed in each of the heat-insulated double containers of Examples 1 to 8 and Comparative Examples 1 and 2 and warmed in a microwave oven at 600 W for 3 minutes, and then the inner surface of each heat-insulated double container was used. The appearance evaluation and the amount of pinholes generated were evaluated according to the following criteria.

(Evaluation of the appearance of the inner surface of the container)
The presence or absence of wrinkles and bubbling on the inner surface of the container was visually confirmed and evaluated according to the following criteria.
A: No wrinkles and good appearance B: Fine wrinkles of less than 5 mm occur C: Large wrinkles of 5 mm or more occur

(Evaluation of pinhole generation amount)
Ten heat-insulating double containers according to Examples 1 to 8 and Comparative Examples 1 to 2 are prepared, and after warming in a microwave oven, a penetrant is poured and the number of containers in which leakage from a pinhole occurs. Counted.

The evaluation results are shown in Table 1 below.

As is clear from Table 1 above, according to the heat-insulated double container according to the embodiment of the present invention, wrinkles, bubbling, and even pinholes occur even when exposed to high temperatures by a microwave oven or the like. Can be suppressed.

10 ... Laminated body 11 ... Base material layer 12 ... Adhesive layer 13 ... Barrier layer 14 ... Seal layer 17 ... Laminating layer 20 ... Cup inner container 21 ... Cup body member 22 ... Bottom member 30 ... Exterior sleeve 100 ... Insulation double container

Claims (6)

A cup-shaped inner container composed of a cylindrical cup body member and a bottom member that seals the bottom of the tubular cup body member.
A heat-insulating double container comprising an exterior sleeve that covers the body member so as to form a heat-insulating space between the cup-shaped inner container and the outer surface of the cup body member.
Both the cup body member and the bottom member are composed of at least a laminated body in which a base material layer made of paper, an adhesive layer, a barrier layer, and a seal layer are laminated.
A heat-insulating double container characterized in that the adhesive layer is a low-density polyethylene resin containing a silane oligomer. The heat-insulating double container according to claim 1, wherein the thickness of the adhesive layer is 15 μm or more and 50 μm or less. The heat-insulating double container according to claim 1 or 2, wherein the barrier layer is formed by laminating an inorganic oxide-deposited film or a metal-deposited film on one surface of a resin film. The seal layer in either or both of the laminate constituting the cup body member and the laminate constituting the bottom member has a density of 0.900 or more and 0.925 or less, and a melt index of 1.0 or more. The heat-insulating double container according to any one of claims 1 to 3, which is 20.0 or less and contains an ethylene-α / olefin copolymer resin polymerized using a single-site catalyst. The heat insulating double container according to claim 4, wherein a laminating layer is provided between the barrier layer and the sealing layer. The heat insulating double container according to claim 4 or 5, wherein the melting point of the adhesive layer is higher than the melting point of the sealing layer.

Images