JP6987288B1 - Container with lid containing composite film, lid material, and contents - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of defects such as tearing and residual holes during peeling for forming an opening in a lid material capable of forming an opening in a partially peeled portion before fully opening, and reliable peeling is possible. Provided are a composite film that realizes excellent peel strength, a lid material formed from the composite film, and a container with a lid containing contents. SOLUTION: As a composite film forming a lid material, an easily peelable resin layer and a polyester film arranged on both sides thereof have a specific configuration. Specifically, in the composite film 1 containing the first polyester film layer 8a, the easily peelable resin layer 10, and the second polyester film layer 8b in this order, the first polyester film layer 8a is both sides thereof. It is assumed that neither of them has been subjected to corona treatment, and that at least the surface of the second polyester film layer 8b in contact with the easily peelable resin layer 10 has been subjected to corona treatment, and the components and composition of the easily peelable resin layer are determined. It shall be in a specific range. [Selection diagram] Fig. 1

Description

The present invention relates to a composite film, a lid material, and a container with a lid containing contents. More specifically, the present invention relates to a composite film for forming a lid material, a lid material formed from the composite film, and a container with a lid containing contents. Here, the lid material may be a lid material capable of forming an opening for discharging the liquid in the partially peeled portion before the entire lid is removed and the package is fully opened.

Conventionally, it is used for packaging instant foods such as yakisoba, which is cooked by pouring hot water into a container with a lid and then draining it, and boiled vegetables and eggs that are taken out after draining water. A lid material having a partially peeled portion for forming an opening before opening is applied.

Examples of such a lid material include, in Patent Document 1, a laminate having a structure of a paper layer / polyester layer (PET layer) / easily peelable resin layer / adhesive layer / intermediate layer / sealant layer, and a paper layer / adhesive layer. A laminate having a structure of / easily peelable resin layer / PET layer / intermediate layer / sealant layer has been proposed.

Further, for example, in Patent Document 2, the paper layer / polyester layer / easily peelable resin layer / polyester layer / barrier layer / sealant layer are laminated in this order from the outer surface side, and are arranged so as to sandwich the easily peelable resin layer. One of the polyester layers is laminated with the easily peelable resin layer through the surface that has been roughened, and the interface between the other polyester layer and the easily peelable resin layer can be peeled off as a peeling surface. Moreover, there has been proposed a lid material characterized in that the paper layer is cured by applying a varnish. In Patent Document 2, the surface wetting tension of the polyester layer (PET layer) forming the peelable surface at the interface with the easily peelable resin layer is 3.5 × 10 ^-2 N / m (35 dyn /). cm) to 6.0 × 10 ^-2 N / m (60 dyn / cm) or less, and when the surface wetting tension is ^{less than 3.5 × 10 -2} N / m, the adhesive strength is excessively reduced. Inadvertent peeling is likely to occur, and if it ^{exceeds 6.0 × 10-2} N / m, the adhesive strength is too improved and it becomes difficult to peel from the easily peelable resin layer 10.

All of these lid materials form openings for hot water drainage and drainage by peeling off the interface between the polyester layer such as the PET layer and the easily peelable resin layer as a peeling surface.

Japanese Unexamined Patent Publication No. 2007-320580 International Publication No. 2012/073274

Conventionally, depending on the material used, the lid material that forms an opening for hot water draining or draining has an appearance due to the lid material being torn or the peeled surface becoming cloudy when peeling to form an opening. In some cases, defects occurred. That is, in the lid material that forms openings for draining and draining water, the difference in peel strength has a great effect on the product. For example, if the peel strength is too strong, the lid material is torn, while peeling. If the strength is too weak, the opening may not appear well, and problems such as hole residue and hole dropout may occur.

The present invention has been made in view of the above background, and is a lid material capable of forming an opening in a partially peeled portion before being fully opened. It is an object of the present invention to provide a composite film that suppresses the occurrence of such defects and realizes peeling strength capable of reliable peeling, a lid material formed from the composite film, and a container with a lid containing contents.

The present inventors have conducted diligent studies to solve the above problems. Then, they have found that the above problems can be solved if the easily peelable resin layer and the polyester films arranged on both sides thereof are configured as the composite film for forming the lid material, and have completed the present invention. That is, the present invention is as follows.

<< Aspect 1 >>
The first polyester film layer, the easily peelable resin layer, and the second polyester film layer are included in this order.
The first polyester film layer and the second polyester film layer are adhered to each other by the easily peelable resin layer.
The first polyester film layer is not corona-treated on both sides thereof.
In the second polyester film layer, at least the surface in contact with the easily peelable resin layer is subjected to corona treatment.
The easily peelable resin layer is composed of a mixture of polyethylene and a cyclic olefin copolymer.
The ratio of the cyclic olefin copolymer to the total of the polyethylene and the cyclic olefin copolymer is 1 to 10% by mass, and the interface between the first polyester film layer and the easily peelable resin layer is used as a peeling surface. Can be peeled off,
Composite film.
<< Aspect 2 >>
A heat seal layer is provided on the side of the first polyester film layer opposite to the easily peelable resin layer, or on the side of the second polyester film layer opposite to the easily peelable resin layer. The composite film according to aspect 1.
<< Aspect 3 >>
The composite film according to aspect 1 or 2, wherein the polar component of the surface free energy of the surface of the first polyester film layer in contact with the easily peelable resin layer is 9.0 mN / m or less.
<< Aspect 4 >>
The composite film according to any one of aspects 1 to 3, wherein the polar component of the surface free energy of the peeled surface of the first polyester film layer after the peeling is 2.0 mN / m or less.
<< Aspect 5 >>
A lid material formed from the composite film according to any one of aspects 1 to 4.
<< Aspect 6 >>
A first half-cut having a depth that reaches the easily peelable resin layer from the side of the first polyester film layer.
A second depth that penetrates the easily peelable resin layer from the side of the second polyester film layer in the thickness direction and reaches at least the interface between the easily peelable resin layer and the first polyester film layer. Half-cut and third half-cut, as well as peripheral stripping tabs,
Equipped with
The first half-cut and the partial peeling tab define the outer edge of the partial peeling portion.
The second half cut defines the outer edge of the liquid flow hole.
The third half-cut defines a tab for partial peeling, and the liquid flow hole is arranged in the partial peeling portion.
As a result, when the partial peeling tab is picked and the partial peeling portion is peeled off, the part other than the liquid flow hole is peeled off at the interface between the first polyester film layer and the easily peelable resin layer. In addition, at the location of the liquid flow hole, the second polyester film accompanies the first polyester film layer without peeling at the interface between the first polyester film layer and the easily peelable resin layer. Removed to form the liquid flow hole,
The lid material according to aspect 5.
<< Aspect 7 >>
A container body with a storage part and a flange part,
The contents contained in the container body and
With the lid material according to aspect 5 or 6,
Equipped with
The lid material is heated to the side of the first polyester film layer opposite to the easily peelable resin layer, or to the side of the second polyester film layer opposite to the easily peelable resin layer. Equipped with a sealing layer,
The lid material is heat-sealed to the flange portion via the heat-sealing layer.
A container with a lid containing the contents.

According to the composite film of the present invention, when a lid material capable of forming an opening in a partially peeled portion is formed before full opening, a lid material capable of reliable peeling for forming the opening is realized. be able to. That is, it is possible to suppress the occurrence of appearance defects such as breakage of the lid material and cloudiness of the peeled surface at the time of peeling for forming an opening.

It is sectional drawing of the composite film and the lid material which concerns on one Embodiment of this invention. It is a top view of the lid material which concerns on one Embodiment of this invention. It is explanatory drawing of the use example of the cover material which concerns on one Embodiment of this invention.

《Composite film》
The composite film of the present invention contains at least a first polyester film layer, an easily peelable resin layer, and a second polyester film layer in this order, and includes a first polyester film layer and a second polyester film layer. Are adhered to each other by an easily peelable resin layer. The surfaces of the first polyester film layer and the second polyester film layer, and the easily peelable resin layer have a specific configuration.

Specifically, in the composite film of the present invention, the first polyester film layer is not subjected to corona treatment on both sides thereof, and the second polyester film layer is at least on the surface in contact with the easily peelable resin layer. , Corona treatment is applied, the easily peelable resin layer is composed of a mixture of polyethylene and a cyclic olefin copolymer, and the ratio of the cyclic olefin copolymer to the total of polyethylene and the cyclic olefin copolymer is 1 to 10 mass. %.

In the composite film of the present invention, the easily peelable resin layer and the first and second polyester film layers arranged on both sides thereof have such a specific configuration, so that the composite film can be easily peeled off from the first polyester film layer. Delamination is possible at the interface with the sex resin layer.

In the easily peelable resin layer, the peel strength at the interface between the first polyester film layer and the easily peelable resin layer can be controlled by changing the mixing ratio of polyethylene and the cyclic olefin copolymer.

Generally, when the content of the cyclic olefin copolymer is high, the peel strength becomes small, and when the content exceeds a certain level, the interlayer strength becomes too weak and unintended peeling occurs, making it difficult to maintain the lamination. On the other hand, when the content of the cyclic olefin copolymer is low, the peel strength at the interface between the first polyester film layer and the easily peelable resin layer becomes high, and peeling becomes difficult.

In the easily peelable resin layer in the composite film of the present invention, the ratio of the cyclic olefin copolymer to the total of polyethylene and the cyclic olefin copolymer is as small as 1 to 10% by mass, and the content of the cyclic olefin copolymer is relatively low. Generally, in such a case, the peel strength tends to be high and the peeling tends to be difficult. However, in the present invention, it is assumed that the first polyester film layer is not corona-treated on both sides thereof, and at least the surface of the second polyester film layer in contact with the easily peelable resin layer is corona-treated. By assuming that, the peeling at the interface between the first polyester film layer and the easily peelable resin layer can be surely performed.

Also, corona treatment is generally performed to increase the polar groups on the surface of the polymer film, thereby improving the adhesion to adjacent layers. Therefore, when peeling at the interface between the first polyester film layer and the easily peelable resin layer as in the present invention, the surface of the first polyester film layer opposite to the easily peelable resin layer is formed on the surface of the first polyester film layer on the opposite side to the easily peelable resin layer. Corona treatment is applied to improve adhesion with other layers, and the surface of the first polyester film layer on the easily peelable resin layer side is not subjected to corona treatment and is easily peeled off from the first polyester film layer. It is carried out to promote peeling at the interface with the sex resin layer.

However, the inventors of the present invention consider that the first polyester film layer is not corona-treated on both sides thereof, so that the content of the cyclic olefin copolymer in the easily peelable resin is relatively low. Also, it was found that the peeling at the interface between the first polyester film layer and the easily peelable resin layer can be surely performed.

Without being bound by theory, this is because the first polyester film layer is easily peeled off even when only the surface opposite to the easily peelable resin layer of the first polyester film layer is subjected to corona treatment. It is considered that the corona treatment also affects the surface on the resin layer side.

In the lid material that forms openings for draining and draining water, the difference in peel strength has a great effect on the product. For example, if the peel strength is too strong, the lid material is torn, while the peel strength is high. If it is too weak, the opening may not appear well, and problems such as hole residue and hole dropout may occur. For this reason, in the lid material for forming the pores, control for achieving the desired peel strength has become an important matter.

In general, when the laminate is formed, a corona treatment is applied to ensure the adhesiveness between the layers. However, the present inventors have found that a slight deviation from the desired peel strength is peeled off. It was found that the corona treatment on the surface on the non-surface side had an effect.

In addition, the corona treatment varies depending on the treatment equipment, treatment conditions, etc., and often differs depending on the lot. Therefore, even if the same resin is selected, different peel strengths are obtained, which is difficult to control. I was in a situation.

Therefore, if a polyester film that has not been subjected to corona treatment on both sides as in the present invention is used, the peel strength does not vary and the corona treatment process can be reduced, which is advantageous in terms of production cost. ..

Hereinafter, the configuration of the composite film of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a composite film according to an embodiment of the present invention.

The composite film 1 according to the embodiment of the present invention shown in FIG. 1 has a paper layer 7, a first polyester film layer 8a, an easily peelable resin layer 10, a second polyester film layer 8b, and a barrier from the outer surface side. It is a laminated body in which the layer 11 and the heat seal layer 12 are laminated in this order.

In the composite film 1 according to one embodiment, the interface between the first polyester film layer 8a adjacent to the paper layer 7 and the easily peelable resin layer 10 can be peeled off, and this interface is the peeling surface 13 at the time of peeling. Is to form. That is, in the composite film 1 according to the embodiment, the paper layer 7 and the first polyester film layer 8a adjacent to the paper layer 7 form the outer surface layer 9 with the peeling surface 13 as a boundary, and the peelability is easy. The resin layer 10, the second polyester film layer 8b, the barrier layer 11, and the heat seal layer 12 constitute the inner surface layer 14. The outer surface layer 9 and the inner surface layer 14 are laminated so as to be peelable, with the interface between the two as the peeling surface 13.

The composite film of the present invention includes a first polyester film layer, an easily peelable resin layer, and a second polyester film layer in this order, and the first polyester film layer and the second polyester film layer are Any layer other than these may be provided as long as they are adhered to each other by the easily peelable resin layer.

The composite film 1 according to the embodiment shown in FIG. 1 includes a paper layer 7 as an arbitrary outer surface layer 9, and a barrier layer 11 and a heat seal layer 12 as an arbitrary inner surface layer 14.

The thickness and the like of each layer constituting the composite film of the present invention can be appropriately determined according to the use and the like of the composite film. Hereinafter, each layer will be described.

<First polyester film layer>
The first polyester film layer is an essential constituent layer in the composite film of the present invention. The first polyester film layer is a layer adjacent to the easily peelable resin layer and laminated on the second polyester film layer via the easily peelable resin layer.

(material)
The polyester resin used as the material of the first polyester film layer is not particularly limited. For example, general resins such as polyethylene terephthalate (PET), polyethylene terephthalate (PEN), polybutylene terephthalate (PBT), polybutylene terephthalate (PBN), polycyclohexane terephthalate (PCT), and polycarbonate (PC). good.

The polyester resin used as the material of the first polyester film layer may be one kind alone or two or more kinds of compositions. Further, the first polyester film layer contains, if necessary, a small amount of a resin or the like other than the polyester resin or an additive or the like, for example, 20% by mass or less, 10% by mass or less, 5% by mass or less, or 3% by mass. It may be blended in the following amounts.

The polyester resin used as the material of the first polyester film layer and the polyester resin used as the material of the second polyester film layer described later may be the same or different. When the polyester resin forming the first polyester film layer and the second polyester film layer are the same, it becomes easier to adjust the adhesiveness with the easily peelable resin layer depending on the presence or absence of the corona treatment.

The polyester resin used as the material of the first polyester film layer is polyethylene terephthalate (PET) because it is cheaper than other polyester films and is a general material used for food packaging materials. Is preferable.

In the composite film of the present invention, the first polyester film layer is formed from a film preformed using a polyester resin as a material. The polyester film may be unstretched or may be uniaxially or biaxially stretched. From the viewpoint of heat resistance and low shrinkage, a biaxially stretched film is preferable.

(Thickness)
The thickness of the first polyester film layer is not particularly limited. For example, it may be 5 μm or more, 8 μm or more, 10 μm or more, 12 μm or more, or 15 μm or more, and may be 30 μm or less, 25 μm or less, or 20 μm or less. When it is 5 μm or more, it is preferable because it imparts rigidity that can withstand use as a packaging material to the composite film.

(Corona processing)
In the composite film of the present invention, the first polyester film layer is characterized in that both sides thereof are not subjected to corona treatment. That is, in the composite film of the present invention, the first polyester film layer is a corona on an adjacent surface in contact with an easily peelable resin layer having a specific component and a specific composition, and vice versa. No treatment has been applied. The surface in contact with the easily peelable resin layer is a surface that forms an interface to be a peelable surface in the composite film of the present invention.

In the composite film 1 according to the embodiment shown in FIG. 1, the first polyester film layer 8a is subjected to corona treatment on both the surface adjacent to the paper layer 7 and both sides of the easily peelable resin layer 10. No. In the composite film 1, the interface between the first polyester film layer 8a and the easily peelable resin layer 10 is the peeling surface 13.

(Polar component of surface free energy on the surface in contact with the easily peelable resin layer)
The polar component of the surface free energy of the surface of the first polyester film layer in contact with the easily peelable resin layer may be 9.0 mN / m or less. Here, the value of the polar component of the surface free energy is a value before laminating the first polyester film layer on the easily peelable resin layer.

The polar components of the surface free energy of the surface of the first polyester film layer in contact with the easily peelable resin layer are 8.5 mN / m or less, 8.0 mN / m or less, 7.5 mN / m or less, and 7.25 mN / m. Hereinafter, it may be 7.0 mN / m or less, 6.75 mN / m or less, or 6.5 mN / m or less. Further, this value may be 2.0 mN / m or more, 3.0 mN / m or more, 4.0 mN / m or more, 5.0 mN / m or more, or 6.0 mN / m or more.

If the polar component of the surface free energy of the surface of the first polyester film layer in contact with the easily peelable resin layer before laminating the first polyester film layer on the easily peelable resin layer is within the above range, the package is fully opened. When a lid material capable of forming an opening by peeling off the partially peeled portion is formed, it is possible to realize a peeling strength that enables reliable peeling.

Regarding the present invention, the polar component of the surface free energy of the surface of the first polyester film layer in contact with the easily peelable resin layer before laminating the first polyester film layer on the easily peelable resin layer is used as an apparatus. , Double titration Handy contact angle / surface free energy analyzer MSA (KRUSS) is used to measure the contact angle between water and diiodomethane, and the polar component of surface free energy is measured by the OWRK method (Owens, Wendt, Rebbel, Kaelble method). Was analyzed.

(Polar component of surface free energy on the peeled surface)
The composite film of the present invention is peeled off with the interface between the first polyester film layer and the easily peelable resin layer as a peeling surface. The polar component of the surface free energy of the peeled surface of the first polyester film layer after peeling may be 2.0 mN / m or less.

The polar component of the surface free energy of the peeled surface of the first polyester film layer after peeling may be 1.8 mN / m or less, 1.6 mN / m or less, or 1.5 mN / m or less. Further, this value may be 0.5 mN / m or more, 1.0 mN / m or more, or 1.25 mN / m or more.

If the polar component of the surface free energy of the peeled surface of the first polyester film layer after peeling is within the above range, a lid material capable of peeling the partially peeled portion to form an opening before fully opening is provided. When formed, it is possible to realize a peeling strength that enables reliable peeling.

Regarding the present invention, the polar component of the surface free energy of the peeled surface of the first polyester film layer after peeling can be measured as follows:
(1) Peel off at the interface between the first polyester film layer and the easily peelable resin layer.
(2) The peeled surface of the first polyester film layer is wiped with toluene 10 times by moving it in one direction without applying force using a waste cloth moistened with toluene.
(3) After wiping with toluene, in order to dry the toluene, dry it 10 times by moving it in one direction without applying force using a new waste cloth.
(4) After wiping with a dry cloth, the contact angle between water and diiodomethane is measured using a double titration handy contact angle / surface free energy analyzer MSA (KRUSS), and the OWRK method (Owens, Wendt, Rebbel, Kaelble method) is used. The polar component of the surface free energy is analyzed by.

<Second polyester film layer>
The second polyester film layer is an essential constituent layer in the composite film of the present invention. The second polyester film layer is a layer adjacent to the easily peelable resin layer and laminated on the first polyester film layer via the easily peelable resin layer.

(material)
The polyester resin used as the material of the second polyester film layer is the same as the polyester resin used as the material of the first polyester film layer described above.

(Thickness)
The thickness of the second polyester film layer is the same as the thickness of the first polyester film layer described above.

(Corona processing)
In the composite film of the present invention, at least the surface of the second polyester film layer in contact with the easily peelable resin layer is subjected to corona treatment. At least the surface in contact with the easily peelable resin layer may be corona-treated, and both sides may be corona-treated.

<Easy peelable resin layer>
The easily peelable resin layer is an essential constituent layer in the composite film of the present invention, and is a layer located between the first polyester film layer and the second polyester film layer described above and adhering these layers to each other. be.

The easily peelable resin layer is composed of a mixture of polyethylene and a cyclic olefin copolymer, and these are mixed in a predetermined ratio. The mixture constituting the easily peelable resin layer may contain polyethylene and a cyclic olefin copolymer as essential components, and may contain other resins, additives and the like to the extent that the effects of the present invention are not impaired. ..

(polyethylene)
Examples of the polyethylene constituting the easily peelable resin layer of the present invention include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE) and the like. Be done.

Among them, low density polyethylene (LDPE) or linear low density polyethylene (LDPE) or linear low density from the viewpoint that it is easy to process, inexpensive, stable in supply, and is a resin generally used for food packaging. It is preferable to use density polyethylene (LLDPE).

Low-density polyethylene (LDPE) or linear low-density polyethylene (LLDPE) contains 80 mol% or more, 90 mol% or more, 95 mol% or more, or 98 mol% or more of repeating units of methylene groups, including branched chains, or A polyethylene having ^{a density of less than 0.930 g / cm 3} in which substantially all repeating units are methylene groups.

When the polyethylene constituting the easily peelable resin layer of the present invention is low density polyethylene (LDPE) or linear low density polyethylene (LLDPE), the density is 0.925 g / cm ³ or less, or 0. .923g / cm ³ may be less, 0.870 g / cm ³ or more, 0.875 g / cm ³ or more, 0.880 g / cm ³ or more, 0.900 g / cm ³ or more, 0.910 g / cm ³ The above, or 0.915 g / cm ³ or more may be used.

Low density polyethylene (LDPE) or linear low density polyethylene (LLDPE) may have a long-chain or short-chain branched structure. The short-chain branched structure is derived from α-olefins having 4 to 18, 4 to 10 or 4 to 8 carbon atoms, such as 1-butene, 1-hexene, 4-methylpentene-1, 1-octene and the like. It may have a branched structure.

The thermal properties of the polyethylene constituting the easily peelable resin layer of the present invention are not particularly limited, but for example, the melt mass flow rate thereof is JIS at a temperature of 190 ° C. and a load of 21.18 N. When measured in accordance with K6922-1 and -2 and JIS K7210-1, preferably 0.1 g / 10 min or more, 0.5 g / 10 min or more, 1.0 g / 10 min or more, 2.0 g / 10 min or more. It may be 3.0 g / 10 min or more, 5.0 g / 10 min or more, 100 g / 10 min or less, 50 g / 10 min or less, 30 g / 10 min or less, 20 g / 10 min or less, or 10 g / 10 min or less. ..

(Cyclic olefin copolymer)
The cyclic olefin copolymer is a polymer in which a cyclic olefin is used as a monomer, and has a saturated hydrocarbon ring structure in the main chain or side chain of the polymer.

The cyclic olefin copolymer constituting the easily peelable resin layer of the present invention is preferably a copolymer containing at least one cyclic olefin and at least one vinyl compound other than the cyclic olefin as monomers.

Further, the cyclic olefin copolymer may be a cyclic olefin-based random copolymer (COC) by addition polymerization using at least one cyclic olefin and at least one vinyl compound other than the cyclic olefin as a monomer. A cyclic olefin ring-opening polymer by ring-opening polymerization or a hydrogenated product thereof using at least one compound having a double bond in the fused ring skeleton and at least one unsaturated compound other than the compound as a monomer (ring-opening polymerization). COP) may be used.

When the cyclic olefin copolymer constituting the easily peelable resin layer of the present invention is a cyclic olefin-based random copolymer (COC) by addition polymerization, the cyclic olefin as a monomer is not particularly limited. , For example, cyclobutene, 3-methylcyclobutene, 3,4-diisopropenylcyclobutene, cyclopentene, 1-methylcyclopentene, 3-methylcyclopentene, cyclohexene, cyclooctene, 1-methylcyclooctene, 5-methylcyclooctene, Examples thereof include monocyclic cycloolefins such as cyclooctatetraene and cyclododecene, polycyclic cycloolefins such as tetracyclododecene and norbornene, and derivatives thereof.

The vinyl compound other than the cyclic olefin, which is a comonomer of the cyclic olefin-based random copolymer (COC), is not particularly limited, and is, for example, ethylene, propylene, 1-butane, 1-pentene, 1 Α-olefins such as −hexene, 1-pentene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, and 1-decene, cyclo Monocyclic diene such as pentadiene, 1,3-cyclohexadiene, 1,4-cyclohexadiene, polycyclic diene having norbornene ring having two unsaturated bonds, linear or branched diene such as butadiene and isoprene, etc. Can be mentioned.

When the cyclic olefin copolymer constituting the easily peelable resin layer of the present invention is a cyclic olefin ring-opening polymer by ring-opening polymerization or a hydrogenated product thereof (COP), it is double-bonded to the fused ring skeleton as a monomer. The compound having the above is not particularly limited as long as it can be polymerized by a metasense polymerization catalyst. For example, compounds having a norbornene-based skeleton such as tetracyclododecene, norbornene, or derivatives thereof can be mentioned.

Further, the unsaturated compound other than the compound having a double bond in the condensed ring skeleton, which is a comonomer of the cyclic olefin ring-opening polymer, is not particularly limited as long as it can be polymerized by a metasense polymerization catalyst. For example, a cyclic olefin which is a monomer of the above-mentioned cyclic olefin-based random copolymer (COC), a cyclic diene, a monomer having a carbon-carbon double bond in the main chain, and derivatives thereof can be mentioned. ..

The cyclic olefin ring-opening polymer has a carbon-carbon double bond (C = C) in the main chain. Then, when hydrogenation is carried out, a hydrogenated product (COP) in which the double bond of the main chain becomes a carbon-carbon single bond (CC) can be obtained. From the viewpoint of heat resistance, weather resistance and the like, a polymer in which at least a carbon-carbon double bond of the main chain is hydrogenated may be used.

(composition)
In the mixture constituting the easily peelable resin layer, the composition of polyethylene and the cyclic olefin copolymer, which are essential components, is such that the ratio of the cyclic olefin copolymer to the total of polyethylene and the cyclic olefin copolymer is 1 to 10% by mass.

The ratio of the cyclic olefin copolymer to the total of polyethylene and the cyclic olefin copolymer is 2% by mass or more, 3% by mass or more, 4% by mass or more, 5% by mass or more, 6% by mass or more, 7% by mass or more, 8% by mass or more, Alternatively, it may be 9% by mass or more, less than 10% by mass, 9% by mass or less, 8% by mass or less, 7% by mass or less, 6% by mass or less, 5% by mass or less, 4% by mass or less, 3% by mass or less, Alternatively, it may be 2% by mass or less.

(Thickness)
The thickness of the easily peelable resin layer is preferably 10 μm or more, 12 μm or more, in order to obtain stable peelability with the first polyester film layer and stable adhesiveness with the second polyester film layer. It may be 14 μm or more, 16 μm or more, 18 μm or more, 20 μm or more, 22 μm or more, or 24 μm or more, and may be 30 μm or less, 28 μm or less, 26 μm or less, 24 μm or less, 22 μm or less, or 20 μm or less.

<Other layers>
The composite film of the present invention may optionally include other layers in addition to the first polyester film layer, the easily peelable resin layer, and the second polyester film layer.

The other layers can be arranged on the side opposite to the easily peelable resin layer of the first polyester film layer, or on the side opposite to the easily peelable resin layer of the second polyester film layer.

Above all, heat is applied to the outermost surface of the first or second polyester film layer on the side opposite to the easily peelable resin layer, particularly on the outermost surface of the second polyester film layer on the side opposite to the easily peelable resin layer. It is preferable that the seal layer is arranged. By providing the heat-sealing layer on the outermost surface, it is possible to heat-seal the composite films or between the composite films and other materials when forming a package or the like using the composite film of the present invention.

Further, on the outermost surface of the first or second polyester film layer on the side opposite to the easily peelable resin layer, particularly on the outermost surface of the first polyester film layer on the side opposite to the easily peelable resin layer. It is preferable that the base material layer is arranged. Since the base material layer is the surface layer of the composite film, it becomes the outer layer of the package or the like when the composite film of the present invention is used to form the package or the like. When the innermost layer is provided with a heat-sealing layer, it can also serve as a protective layer when heat-sealing to form a package or the like. Further, the base material layer can be printed for displaying the contents of the package or the like.

The other layers are not particularly limited, and other than the base material layer and the heat seal layer, for example, a barrier layer for imparting barrier properties, a reinforcing layer for reinforcing strength, or a layer and a layer. Examples thereof include an adhesive layer for adhering between the spaces. Although not shown in FIG. 1, in the composite film 1 according to the embodiment of the present invention shown in FIG. 1, the first polyester film layer 8a and the paper layer 7, the second polyester film layer 8b and the barrier layer 11 Are bonded together by an adhesive layer. The first polyester film layer 8a, the easily peelable resin layer 10, and the second polyester film layer 8b are directly bonded to each other by sand laminating. Further, the barrier layer 11 and the heat seal layer 12 are directly bonded to each other by extrusion laminating.

In the composite film 1 according to the embodiment of the present invention shown in FIG. 1, as another layer, the paper layer 7 is on the outermost surface of the first polyester film layer 8a on the side opposite to the easily peelable resin layer 10. , The barrier layer 11 and the heat seal layer 12 are arranged on the side of the second polyester film layer 8b opposite to the easily peelable resin layer 10.

(Base layer)
In the composite film of the present invention, the base material layer, which is an arbitrary constituent layer, may be a single layer or a laminated body composed of a plurality of layers.

When the base material layer is a single layer, the base material layer may be a resin, particularly a resin layer made of a resin that serves as a protective layer and enables printing. When the base material layer is a resin layer, a commonly used resin can be used as the material, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (). Examples thereof include polyesters such as PBT), polyethylenes (PE), polypropylenes (PP), polyolefins such as polystyrene (PS), polyamides (PA) such as nylon-6 and nylon-66, and polycarbonates (PC).

The above resin may be blended with not only one type but also two or more types, and if necessary, an additive or the like for imparting functionality or the like may be blended.

When the base material layer is a resin layer, a preformed resin film may be applied. The resin film to be the base material layer may be a film formed from the above resin or the like, and may be unstretched or may be uniaxially or biaxially stretched. Among them, a biaxially stretched film is preferable.

Alternatively, the base material layer may be a layer made of a material other than resin, for example, a paper layer or the like. Examples of the paper layer include high-quality paper, coated paper, art paper, and the like. When the paper layer is the outermost layer of the composite film, the paper layer may be printed with gravure printing, flexographic printing, or the like.

Further, the base material layer may be formed with an inorganic material vapor-deposited film on which a metal such as aluminum or an inorganic substance such as silicon oxide or aluminum oxide is vapor-deposited. Alternatively, it may have a barrier coat layer such as a vinylidene chloride coat layer and a polyvinylidene fluoride coat layer. Further, when the base material layer is composed of a resin film, a roughening treatment or the like for roughening the surface thereof may be performed.

When the base material layer is a laminated body of two or more layers, a plurality of layers made of the resin in the case of the above-mentioned single layer may be provided, or a layer made of a material other than the resin may be provided. You may.

(Heat seal layer)
In the composite film of the present invention, the heat seal layer, which is an arbitrary constituent layer, is a layer used for heat seal when forming a package or the like using the composite film of the present invention. Therefore, the heat seal layer is arranged so as to be the innermost layer of the composite film.

The material constituting the heat-sealing layer is not particularly limited as long as it can be heat-sealed and can impart sufficient sealing strength to a package or the like formed from the composite film of the present invention. Known materials can be applied, such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), polypropylene (PP), ethylene- Examples thereof include propylene copolymer (EP), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ionomer resin, ethylene-vinyl acetate copolymer (EVA) and the like.

For example, when forming a packaging bag or the like to be filled with contents, the heat seal layer is a layer forming a space for filling the contents. Therefore, when it is desired to impart content resistance, it is preferable to use, for example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), or the like.

The heat seal layer may be formed by using a film preformed from the above materials, or may be formed by melting and extruding the material for forming the heat seal layer and cooling and solidifying the material.

Further, the resin or the like constituting the heat seal layer may be blended with not only one kind but also two or more kinds, and if necessary, an additive or the like for imparting functionality or the like is blended. May be good.

Further, the heat seal layer may be a single layer or may be composed of a plurality of layers.

The heat seal layer may have an easy peeling property (easy opening property) so that the joint portion can be easily opened at the time of use. If the heat seal layer has an easy peel property, for example, when a lid material is formed from the composite film of the present invention and heat-sealed with the container body to form a package, the contents can be opened for taking out the contents. It will be easy.

(Barrier layer)
The barrier layer is a layer for imparting barrier properties to the composite film.

The barrier layer includes, for example, ethylene-vinyl alcohol copolymer (EVOH), nylon (NY), polyvinylidene chloride (PVDC), or polyacrylonitrile (PAN), which exhibits a function of blocking gases such as oxygen and water vapor. Examples thereof include a resin layer made of the above.

The above resin may be blended with not only one type but also two or more types, and if necessary, an additive or the like for imparting functionality or the like may be blended.

Alternatively, for example, an inorganic vapor-deposited film layer, a metal foil layer, an organic coat layer, or the like may be used.

Examples of the inorganic thin-film vapor deposition film layer to be the barrier layer include a silica-film-deposited film, an aluminum-film-deposited film, an alumina-deposited film, and a silica-alumina-deposited film.

Examples of the metal foil serving as the barrier layer include metal foils such as aluminum foil, copper foil, and titanium foil, and alloy foils such as aluminum alloy foil and stainless steel foil.

The organic coat layer to be the barrier layer may be a barrier coat layer such as a vinylidene chloride coat layer or a polyvinylidene fluoride coat layer.

When an inorganic vapor-deposited film layer or an organic coat layer is present as the barrier layer, the thickness of the barrier layer should be 100 nm or more, 200 nm or more, 300 nm or more, 500 nm or more, 700 nm or more, or 1 μm or more. It is preferable from the viewpoint of ensuring the barrier property, and 5 μm or less, 4 μm or less, 3 μm or less, or 2 μm or less is preferable from the viewpoint of improving the handleability when the composite film is used as a packaging material or the like.

When a metal foil is present as the barrier layer, the thickness of the barrier layer is preferably 5 μm or more, 7 μm or more, 10 μm or more, or 15 μm or more from the viewpoint of ensuring strength and barrier properties. Further, it is preferable that the thickness is 100 μm or less, 80 μm or less, 60 μm or less, 55 μm or less, 50 μm or less, 45 μm or less, 40 μm or less, or 35 μm or less from the viewpoint of improving the handleability when the composite film is used as a packaging material or the like.

(Reinforcing layer)
The reinforcing layer is a layer for reinforcing the strength of the composite film. Examples of the material of the reinforcing layer include coated paper, paper such as art paper, synthetic paper, non-woven fabric and the like. When a paper or the like as a reinforcing layer is present on the outermost surface of the composite film, printing such as gravure printing or flexographic printing may be performed on the surface thereof.

(Adhesive layer)
The adhesive layer exists between layers and is a layer for adhering layers to each other. Examples of the adhesive layer include a layer made of an ethylene-acrylic acid copolymer (EAA), an ethylene-methacrylic acid copolymer (EMAA), and an ionomer.

Further, the adhesive layer may be a layer made of an adhesive. For example, it may be a dry laminate adhesive, a hot melt adhesive, a water-soluble adhesive, an emulsion adhesive, a non-solvent laminate adhesive, a thermoplastic resin for extrusion lamination, or the like.

<< Manufacturing method of composite film >>
The method for producing the composite film of the present invention is not particularly limited, and a known method can be applied. For example, a dry lamination method, a hot melt lamination method, an extrusion lamination method, a sandwich lamination method and the like can be mentioned.

<< Applications of composite film >>
The use of the composite film of the present invention is not particularly limited. For example, it may be used as a packaging material to form a packaging bag, a lid material, or the like.

<Packaging bag>
The composite film of the present invention may be used as a packaging material to form a packaging bag. When the composite film of the present invention includes a heat-sealing layer, the sheet-sealing layers can be heat-sealed with each other to form a three-way sealing bag, a four-way sealing bag, a gusset packaging bag, a pillow packaging bag, or the like.

<Cover material>
A lid material may be molded from the composite film of the present invention. For example, it can be a lid material for sealing the upper end opening of the container body.

(half cut)
The lid material obtained from the composite film of the present invention may have a half cut. The half cut may be appropriately provided depending on the use of the composite film.

For example, when the composite film of the present invention is used as a lid material in which the interface between the first polyester film layer and the easily peelable resin layer is used as a peeling surface and holes can be formed in the partially peeled portion before opening. The first half-cut having a depth reaching the easily peelable resin layer from the side of the first polyester film layer and the easily peelable resin layer penetrating from the side of the second polyester film layer in the thickness direction. It may have a second half-cut and a third half-cut at a depth that at least reaches the interface between the easily peelable resin and the first polyester film layer. Here, the second half-cut and the third half-cut may be at a depth reaching the first polyester film layer.

Such a lid material is provided with a tab for opening and a tab for partial peeling on the peripheral portion, a first half cut and a tab for partial peeling define an outer edge of the partial peeling portion, and a second half cut is provided. , The outer edge of the liquid flow hole is defined, and the third half cut defines the tab for partial delamination. A liquid flow hole is arranged in the partially peeled portion.

Specifically, at least one second half-cut and a third half-cut were provided in the vicinity of the partial peeling tab, and the second half-cut was formed on both sides of the partial peeling tab. A first half-cut connecting the perimeters is provided to cover the area.

According to this, when the partial peeling tab is picked and the partial peeling portion is peeled off, the part other than the liquid flow hole is peeled off at the interface between the first polyester film layer and the easily peelable resin layer, and the liquid is peeled off. At the location of the flow hole, the second polyester film is removed along with the first polyester film layer without peeling at the interface between the first polyester film layer and the easily peelable resin layer, and the liquid flow hole is formed. Can be formed.

The half-cut of the lid material of the present invention formed from the composite film of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a cross-sectional view of a composite film according to an embodiment of the present invention. FIG. 2 is a plan view of the lid material according to the embodiment of the present invention. FIG. 3 is an explanatory diagram of an example of using the lid material according to the embodiment of the present invention.

The composite film 1 according to the embodiment of the present invention shown in FIG. 1 is also a cross-sectional view of the lid material 1 shown in FIG. The structure of each layer of the composite film 1 is as described above.

The lid material 1 shown in FIG. 2 is composed of a composite film 1, and the composite film 1 is punched into a required lid shape. In the lid material 1 according to one embodiment, a part of a substantially circular peripheral edge extends outward to form an opening tab 2, and a part of the peripheral edge opposite to the opening tab 2. Also extends outward to form a tab 3 for partial peeling.

Further, the lid material 1 has a first half cut 5 as a half cut for partial peeling, a second half cut 4 as a half cut for opening holes, and a third half as a half cut for forming tabs. It has a cut 6.

In the lid material 1, the shape of the second half cut 4 as the half cut for opening is annular, and the lid material 1 has two second half cuts 4 as the half cut for opening. It is provided individually.

In the lid material of the present invention formed from the composite film of the present invention, the tab for partial peeling peels off the outer surface layer (partially peeled portion) covering the formation region of the second half cut as the half cut for opening. This is for facilitating, and is provided on the outer edge of the outer surface layer (partially peeled portion) that covers the formation region of the second half cut. Further, the opening tab is for making it easy to pull the lid material when the entire lid material is peeled off from the container body to be sealed, and is a region for forming a second half cut as a half cut for opening. It may be provided on the outer edge of the outer surface layer other than the outer surface layer (partially peeled portion) covering the above.

In the composite film 1 according to the embodiment of the present invention shown in FIG. 1 and the lid material 1 according to the embodiment of the present invention shown in FIG. 2, the first half cut 5 as the partial peeling half cut is , The outer surface layer 9, that is, the paper layer 7 and the first polyester film layer 8a are penetrated in the thickness direction to reach the peeling surface 13, and the second half cut 4 as a half cut for opening. The third half-cut 6 as the tab-forming half-cut comprises the inner surface layer 14, that is, the heat seal layer 12, the barrier layer 11, the second polyester film layer 8b, and the easily peelable resin layer 10 in the thickness direction. It is a depth that penetrates and reaches the peeling surface 13, that is, the interface between the easily peelable resin layer and the first polyester film layer.

In the lid material 1 obtained from the composite film 1, the first half-cut 5 and the partial peeling tab 3 define the outer edge of the partial peeling portion. The second half cut 4 defines the outer edge of the liquid flow hole, and the liquid flow hole is arranged in the partial peeling portion. Further, the third half cut 6 defines the partial peeling tab 3. According to this, when the partial peeling tab 3 is picked and the partial peeling portion is peeled off, the part other than the liquid flow hole is peeled off at the interface between the first polyester film layer 8a and the easily peelable resin layer 10. It is possible to form a liquid flow hole.

Specifically, in the composite film 1 and the lid material 1, the shape of the second half-cut 4 which is a half-cut for opening is annular, and the formation region of the second half-cut 4 is formed. When the outer surface layer 9 is peeled from the inner surface layer 14 on the peeling surface 13 by the first half cut 5 which is a partial peeling half cut, the inner portion of the annular shape of the second half cut 4 becomes the outer surface layer. An opening can be formed by the accompanying removal in a state of being attached to 9.

Next, an example of using the lid material 1 according to the present invention will be described with reference to FIG.

As shown in FIG. 3A, the lid material 1 is usually used for sealing the container body 16. FIG. 3A is a container with a lid containing the contents, in which the lid material 1 is heat-sealed on the flange portion 17 of the container body 16 in which the contents (not shown) are stored. In the container with a lid containing the contents shown in FIG. 3A, the lid material 1 is covered on the container body 16 with the heat seal layer 12 located on the outermost surface of the inner surface layer 14 on the container body 16 side. The heat seal layer 12 is heat-sealed on the flange portion 17 projecting from the peripheral edge of the opening of the main body 16.

FIG. 3B is a diagram showing a state in which an opening is formed before the container with a lid containing the contents of FIG. 3A is fully opened. As shown in FIG. 3 (b), the tab 3 for partial peeling is picked up and pulled upward to cover the outer surface layer 9 (partially peeled portion) covering the forming region of the second half cut 4 which is a half cut for opening. , It is separated from the outer surface layer 9 of the other region through the third half cut 6 which is a tab forming half cut, and is peeled off from the inner surface layer 14 and removed. When the outer surface layer 9 is peeled off, the opening 15 is formed by removing the inner portion of the second half cut 4 of the inner surface layer 14 in a state of being attached to the outer surface layer 14.

By tilting the container body 16 toward the opening 15 after forming the opening 15, liquid such as water in the container body 16 can be discharged from the opening 15. By making the size of the opening 15 smaller than the size of the contents, it is possible to prevent the contents from flowing out.

FIG. 3C is a diagram showing a state in which the outer surface layer 9 is peeled off to form an opening 15 and then the lid material 1 is removed from the container with a lid to fully open the container. As shown in FIG. 3C, the opening tab 2 is pulled upward, the entire lid material 1 is peeled off from the flange portion 17 of the container body 16, the opening of the container body 16 is fully opened, and the contents are opened. Take out.

When the contents are instant fried noodles, etc., first, in the state of FIG. 3A, pull up the opening tab 2 to partially open the opening of the container body 16 to wrap the ingredients, sauce, etc. Remove from the inside of the container. Then pour hot water and reseal the container. Then, after a certain period of time, an opening 15 is formed as shown in FIG. 3 (b), hot water is drained through the opening 15, and then the opening of the container body 16 is fully opened as shown in FIG. 3 (c). Then, add ingredients and sauce.

In the lid material of the present invention formed from the composite film of the present invention, the shape of the second half-cut, which is a half-cut for opening, is not particularly limited as long as it is annular, and is circular or oval. , Rounded rectangle, oval, triangle, quadrangle, polygon more than pentagon, etc. can be set as appropriate. Since the inner portion of the annular shape of the half-cut for opening is less likely to be caught when the inner portion of the annular shape is attached to the outer surface layer and is removed, a circular shape having no corners, an elliptical shape, a rectangular shape with rounded corners, an oval shape, or the like is preferable. The second half cut may be singular or plural, but it is preferable to form a plurality of the second half cuts in order to facilitate the discharge of the liquid so as to prevent the contents from flowing out.

Further, the first half cut, which is a half cut for partial peeling, is usually formed in a continuous linear shape, and may be formed in a perforation or an intermittent line shape, for example.

The third half-cut, which is a tab-forming half-cut, is a partial peeling tab in order to exert a pulling force on the interface between the outer layer and the inner layer when the partial peeling tab is picked and pulled upward. It may be formed across the base portion from the inner surface side to the same depth as the second half cut which is a half cut for opening.

<Container with lid containing contents>
The container with a lid containing the contents includes a container body, the contents, and a lid material formed from the composite film of the present invention.
(Container body)
The container body for forming a container with a lid containing contents has a storage portion and a flange portion.

The material of the container body is not particularly limited, as long as the heat-sealing layer of the lid material formed from the composite film of the present invention can be heat-sealed. For example, a paper container whose surface is coated with a resin, a resin container, or the like can be mentioned.

{Storage unit}
The storage unit is a portion where the contents are stored. The shape of this portion is not particularly limited, and may be, for example, a substantially conical trapezoid, a polygonal pyramid trapezoid, a rectangular parallelepiped shape, a cube shape, or the like.

{Flange part}
The flange portion is a portion around the upper end opening of the storage portion of the container body. The shape is not particularly limited, and may be, for example, a brim shape. Further, the shape of the outer periphery of the flange portion can be appropriately selected according to the shape of the lid material.

When the container body is made of paper, the flange portion may have a coating with a polyethylene resin.

(Contents)
The contents are those housed in the storage unit. The contents are not particularly limited, and examples thereof include heated foods such as instant noodles, chilled foods, and frozen foods, and non-heated foods such as snack foods, gummy candy, and beverages.

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

<Material>
In the examples and comparative examples, the following were prepared as the materials constituting the layer.

(1) Paper layer-Paper (basis weight: 80 g / m ² )

(2) First polyester film layer-PET film 1 (Company A, thickness: 12 μm)
-PET film 2 (Company B, thickness: 12 μm)
-PET film 3 (Company C, thickness: 8 μm)
-PET film 4 (Company D, thickness: 12 μm)

(3) Easy-Removable Resin Layer Using the following polyethylene and the cyclic olefin copolymer, a mixture was prepared in which the ratio of the cyclic olefin copolymer to the total of the polyethylene and the cyclic olefin copolymer was less than 10% by mass.
-Polyethylene: (Low density polyethylene (LDPE))
・ Cyclic olefin copolymer

(4) Second polyester film layer-PET film 3 (Company C, thickness: 8 μm)

(5) Aluminum layer-Aluminum foil (thickness: 6.5 μm)

(6) Heat seal layer-Easy peeling polyolefin resin

<< Examples 1 to 3 and Comparative Examples 1 to 4 >>
<Making a composite film>
Laminating (paper layer // first polyester film layer / easily peelable resin layer / second polyester film layer // aluminum layer / heat seal layer) by the method shown below using the materials shown in Table 1. A composite film was produced as a constituent. The portion bonded by dry laminating is indicated by "//".

In Examples 1 to 3, the polyester film used as the first polyester film layer was not corona-treated on both sides. In the corresponding Comparative Examples 1 to 3 and Comparative Example 4, a polyester film having a corona treatment on one side is used as the polyester film to be the first polyester film layer, and the surface treated with the corona is a paper layer. A composite film was produced by using the side surface and the surface not subjected to the corona treatment as the surface on the easily peelable resin layer side.

As for the polyester film to be the second polyester film layer, those in which corona treatment was carried out on both sides thereof were used in all of Examples and Comparative Examples.

1. 1. The paper layer and the polyester film to be the first polyester film layer were bonded together by dry laminating to prepare a laminated body of (paper layer // first polyester film layer). As the dry laminating adhesive, a two-component curable dry laminating adhesive was used, and the coating amount was 2.5 g / m ² .

2. 2. The aluminum foil to be the aluminum layer and the polyester film to be the second polyester film layer were laminated by dry laminating to prepare a laminated body (second polyester film layer // aluminum layer). As the dry laminating adhesive, a two-component curable dry laminating adhesive was used, and the coating amount was 2.5 g / m ² .

3. 3. A composition that becomes an easily peelable resin layer is formed between the laminate of (paper layer // first polyester film layer) prepared above and the laminate of (second polyester film layer // aluminum layer). It was sandwiched and sand-laminated to prepare a laminated body of (paper layer // first polyester film layer / easily peelable resin layer / second polyester film layer // aluminum layer). The thickness of the easily peelable resin layer was set to 20 μm.

4. By extruding and laminating an easy-peel polyolefin resin, which is a material for the heat seal layer, on the aluminum layer so as to have a thickness of 20 μm (paper layer // first polyester film layer / easily peelable resin). A composite film having a laminated structure of a layer / a second polyester film layer // an aluminum layer / a heat seal layer) was obtained.

<Making lid material>
The obtained composite film was cut out and subjected to the necessary half-cut to prepare the lid material shown in FIG.

<Making a container with a lid>
The obtained lid material was placed in a foamed polystyrene cup (flange width: 6 mm, opening inner diameter: 157 mm square) using a heated heat seal bar, heat seal width 5 mm, temperature 130 ° C., pressure 0.3 Mpa, time 0. A container with a lid was prepared by heat-sealing under the condition of 3 seconds.

"evaluation"

(Opening test after hot water supply)
With respect to the containers with lids prepared in Examples 1 to 3 and Comparative Examples 1 to 4, the opening tab was picked up, pulled up and opened by about 1/3, then hot water at 98 ° C. was poured, and the tab was bent and resealed. Three minutes after resealing, the partial peeling tab was picked up and pulled up, the partial peeling portion was separated from the outer layer of the other region, and peeled from the inner layer to form an opening. It was visually confirmed whether the paper layer was torn during peeling and the peeled surface was not cloudy. The evaluation criteria are shown below.
〇: The paper layer of the partially peeled part did not remain on the inner surface layer, and there was no white turbidity on the peeled surface of the inner surface layer.

(Analysis of the polar component of the surface free energy of the surface of the first polyester film layer in contact with the easily peelable resin layer)
With respect to the polyester film used as the first polyester film layer of Examples 1 to 3 and Comparative Examples 1 to 4, the polar component of the surface free energy of the surface not subjected to the corona treatment was analyzed. As a device, a double titration handy contact angle / surface free energy analyzer MSA (KRUSS) is used to measure the contact angle between water and diiodomethane, and the surface free energy is measured by the OWRK method (Owens, Wendt, Rebbel, Kaelble method). The polar component was analyzed.

(Analysis of the polar component of the surface free energy of the peeled surface)
The lids prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were peeled off at the interface between the first polyester film layer and the easily peelable resin layer. The peeled surface of the first polyester film layer was wiped with toluene by moving it in one direction without applying force using a waste cloth moistened with toluene. Wiping was performed 10 times for each lid, and a new waste wipe was used for each lid.

After wiping with toluene 10 times, a dry wipe was performed to dry the toluene. The dry wiping was performed 10 times with each lid by moving it in one direction without applying force using a new waste cloth. For each lid after dry wiping, the polar component of the surface free energy was analyzed in the same manner as above.

1 Composite film 2 Opening tab 3 Partial peeling tab 4 Second half cut 5 First half cut 6 Third half cut 7 Paper layer 8a First polyester film layer 8b Second polyester film layer 9 Outer surface layer 10 Easy-to-peelable resin layer 11 Barrier layer 12 Heat-seal layer 13 Detachable surface 14 Inner surface layer 15 Open holes 16 Container body 17 Flange part

Claims (7)

The first polyester film layer, the easily peelable resin layer, and the second polyester film layer are included in this order.
The first polyester film layer and the second polyester film layer are adhered to each other by the easily peelable resin layer.
The first polyester film layer is not corona-treated on both sides thereof.
In the second polyester film layer, at least the surface in contact with the easily peelable resin layer is subjected to corona treatment.
The easily peelable resin layer is composed of a mixture of polyethylene and a cyclic olefin copolymer.
The ratio of the cyclic olefin copolymer to the total of the polyethylene and the cyclic olefin copolymer is 1 to 10% by mass, and the interface between the first polyester film layer and the easily peelable resin layer is used as a peeling surface. Can be peeled off,
Composite film. A heat seal layer is provided on the side of the first polyester film layer opposite to the easily peelable resin layer, or on the side of the second polyester film layer opposite to the easily peelable resin layer. The composite film according to claim 1. The composite film according to claim 1 or 2, wherein the polar component of the surface free energy of the surface of the first polyester film layer in contact with the easily peelable resin layer is 9.0 mN / m or less. The composite film according to any one of claims 1 to 3, wherein the polar component of the surface free energy of the peeled surface of the first polyester film layer after the peeling is 2.0 mN / m or less. A lid material formed from the composite film according to any one of claims 1 to 4. A first half-cut having a depth that reaches the easily peelable resin layer from the side of the first polyester film layer.
A second depth that penetrates the easily peelable resin layer from the side of the second polyester film layer in the thickness direction and reaches at least the interface between the easily peelable resin layer and the first polyester film layer. Half-cut and third half-cut, as well as peripheral stripping tabs,
Equipped with
The first half-cut and the partial peeling tab define the outer edge of the partial peeling portion.
The second half cut defines the outer edge of the liquid flow hole.
The third half-cut defines the partial peeling tab, and the liquid flow hole is arranged in the partial peeling portion.
As a result, when the partial peeling tab is picked and the partial peeling portion is peeled off, the part other than the liquid flow hole is peeled off at the interface between the first polyester film layer and the easily peelable resin layer. In addition, at the location of the liquid flow hole, the second polyester film accompanies the first polyester film layer without peeling at the interface between the first polyester film layer and the easily peelable resin layer. Removed to form the liquid flow hole,
The lid material according to claim 5. A container body with a storage part and a flange part,
The contents contained in the container body and
With the lid material according to claim 5 or 6.
Equipped with
The lid material is heated to the side of the first polyester film layer opposite to the easily peelable resin layer, or to the side of the second polyester film layer opposite to the easily peelable resin layer. Equipped with a sealing layer,
The lid material is heat-sealed to the flange portion via the heat-sealing layer.
A container with a lid containing the contents.

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