Composite film

Abstract

To provide a novel composite film having appropriate initial opening strength and resealability, while suppressing residue remaining on an adherend after peeling from the adherend.SOLUTION: As shown in Fig. 1, a composite film of the present invention includes a substrate layer 102, an adhesive layer 104, and a heat seal layer 106 in this order. The substrate layer 102 and the heat seal layer 106 are bonded to each other by the adhesive layer 104. The adhesive layer 104 contains a urethane resin adhesive and a tackifier, and the heat seal layer 106 contains a polyethylene resin.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a composite film, particularly a resealable composite film.

Background Art

[0002] As packaging means for cosmetics, sanitary products, or foods and pharmaceuticals in amounts that cannot be consumed all at once, which are repeatedly opened and resealed each time they are used, various packaging bodies with a resealing function have conventionally been used to prevent the contents remaining after opening from undergoing oxidative deterioration or spoilage due to moisture absorption, drying, etc. As such a packaging body, a multilayer film has been proposed that can impart a resealing function to the packaging body itself without attaching accessories such as a zipper.

[0003] Patent Document 1 discloses a resealable packaging material having a base material layer, an adhesive layer, and a heat seal layer in this order, wherein the adhesive layer contains a thermoplastic elastomer and a polyterpene. When at least a part of the heat seal layer is heat sealed to an adherend and another part of the resealable packaging material is pinched and the resealable packaging material is peeled from the adherend, the adhesive layer and the heat seal layer break, and the surface of the base material layer on the adhesive layer side is exposed at the heat sealed portion, whereby a resealing portion, which is a part of the adhesive layer, is exposed. When the surface of the base material layer on the adhesive layer side is pressed against the resealing portion, the surface of the base material layer on the adhesive layer side and the resealing portion can be adhered to each other.

[0004] Patent Document 2 discloses a composite film including a base material layer, a polyester resin layer, an adhesive layer, and a heat seal layer in this order, wherein the polyester resin layer and the heat seal layer are adhered to each other by the adhesive layer, the adhesive layer contains an amorphous polyester and a rosin ester, and the heat seal layer contains a polyethylene resin.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention provides a novel composite film that has appropriate initial opening strength and resealability, and further suppresses residue on the adherend when peeled off from the adherend.

Means for Solving the Problems

[0007] As a result of intensive studies, the present inventors have found that the above problems can be solved by the following means, and have completed the present invention. That is, the present invention is as follows: <Aspect 1> A composite film including a base material layer, an adhesive layer, and a heat-sealing layer in this order, wherein the base material layer and the heat-sealing layer are adhered to each other by the adhesive layer, the adhesive layer includes a urethane-based adhesive and a tackifier, and the heat-sealing layer includes a polyethylene resin. Composite film. <Aspect 2> The composite film according to Aspect 1, wherein the ratio of the mass of the urethane-based adhesive to the total mass of the urethane-based adhesive and the tackifier is 0.5 to 0.9. <Aspect 3> The composite film according to Aspect 1 or 2, wherein the urethane-based adhesive includes a urethane-urea resin. <Aspect 4> The composite film according to any one of Aspects 1 to 3, wherein the tackifier is a rosin ester. <Aspect 5> The composite film according to any one of Aspects 1 to 4, wherein the thickness of the adhesive layer is 5 μm or less. <Aspect 6> The composite film according to any one of Aspects 1 to 5, wherein the heat-sealing layer does not contain a polypropylene-based resin and a polybutene-based resin. <Aspect 7> The heat-sealing layer is a polyethylene resin layer with a density of 0.920 to 0.965 g / cm 3 The composite film according to any one of Aspects 1 to 6. <Aspect 8> The heat-sealing layer is composed of high-density polyethylene with a density of 0.942 to 0.965 g / cm 3 The composite film according to any one of Aspects 1 to 7. <Aspect 9> A lid material composed of the composite film according to any one of Aspects 1 to 8. <Aspect 10> The lid material according to Aspect 9, which is for resealing. <Aspect 11> The lid material according to Aspect 9 or 10, which does not have a half cut on the heat-sealing layer side. <Aspect 12> A container having a storage part and a flange part, The content stored in the container body, The lid material according to any one of Aspects 9 to 11, Comprising, The heat-sealing layer is heat-sealed to the flange part to form a resealable joint part, A container with a lid containing contents. <Aspect 13> The container with a lid containing contents according to Aspect 12, wherein the content is food.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a novel composite film that has appropriate initial opening strength and resealability, and further suppresses residue on the adherend when peeled off from the adherend.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0010] 《Composite Film》 As shown in FIG. 1, the composite film of the present invention includes a base material layer 102, an adhesive layer 104, and a heat seal layer 106 in this order, wherein the base material layer 102 and the heat seal layer 106 are adhered to each other by the adhesive layer 104, the adhesive layer 104 contains a urethane-based adhesive and a tackifier, and the heat seal layer 106 contains a polyethylene resin.

[0011] The inventors of the present invention have unexpectedly found that even when a urethane-based adhesive is used, by using a tackifier, it has appropriate initial opening strength and resealability. Further, according to the above-described aspect of the adhesive layer, it has been found that when the composite film of the present invention is peeled from an adherend, the remaining of the adhesive layer on the adherend can be suppressed. This is considered to be due to the fact that according to the adhesive layer of the composite film of the present invention, in a configuration for achieving a predetermined reseal strength, a relatively large breaking strength can be achieved. The remaining of the adhesive layer on the adherend will be described in the description of the lid material composed of the composite film of the present invention.

[0012] Hereinafter, each component of the present invention will be described.

[0013] 〈Base Material Layer〉 The base material layer may be a layer including a base material resin layer. Specifically, the base material layer may be a single-layer base material resin layer, or may be a laminate including a base material resin layer. In any aspect, it is preferable from the viewpoint of adhesiveness that the base material resin layer is in direct contact with the adhesive layer. Here, in the present specification, "in direct contact" means contact without intervening other layers, such as an adhesive layer or the like.

[0014] When the base material layer is a laminate including a base resin layer, the base material layer may have, in addition to the base resin layer, a barrier layer, a paper layer, other resin layers, an adhesive layer, etc. The base material layer in this aspect may have, for example, a paper layer, an adhesive layer, a barrier layer, an adhesive layer, and a base resin layer in this order, or may have other resin layers, an adhesive layer, a barrier layer, an adhesive layer, and a base resin layer in this order.

[0015] (Base resin layer) As the base resin layer, for example, thermoplastic resins such as polyolefin resins, vinyl polymers, polyesters, and polyamides can be used alone or in combination of two or more kinds in a multilayer. Such thermoplastic resins can be used in the form of a film or an extruded resin. Also, the film may be a stretched film or an unstretched film.

[0016] Among them, from the viewpoint of coordinating the interlayer peelability and adhesiveness between the base resin layer and the pressure-sensitive adhesive layer, it is preferable to use a polyester resin as the base resin layer.

[0017] As the polyolefin resin, for example, polyethylene resins and polypropylene resins can be used.

[0018] In this specification, the polyethylene resin is a resin containing a repeating unit of an ethylene group in the main chain of the polymer in an amount of more than 50 mol%, 60 mol% or more, 70 mol% or more, or 80 mol% or more, and is, for example, selected from the group consisting of low-density polyethylene (LDPE), high-density polyethylene (HDPE), ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), and derivatives thereof, and mixtures thereof.

[0019] In this specification, the polypropylene-based resin is a resin containing, in the main chain of the polymer, repeating units of propylene groups in an amount exceeding 50 mol%, 60 mol% or more, 70 mol% or more, or 80 mol% or more. Examples thereof include polypropylene (PP) homopolymer, random polypropylene (random PP), block polypropylene (block PP), chlorinated polypropylene, acid-modified polypropylene, and derivatives thereof, as well as mixtures thereof.

[0020] Examples of the vinyl-based polymer include polyvinyl chloride (PVC).

[0021] Examples of the polyester include polyethylene terephthalate (PET), polybutylene terephthalate, and the like.

[0022] Examples of the polyamide include nylon such as nylon (registered trademark) 6 and nylon MXD6.

[0023] Furthermore, the base resin layer may include other layers such as an inorganic vapor deposition layer, a barrier coat layer, and an adhesive layer. As the inorganic vapor deposition layer, a silica vapor deposition film, an aluminum vapor deposition film, an alumina vapor deposition film, or a silica-alumina vapor deposition film can be used. As the barrier coat layer, a vinylidene chloride coat layer or a polyvinylidene fluoride coat layer can be used.

[0024] (Barrier layer) As the barrier layer, for example, an inorganic vapor deposition layer, a metal foil layer, an organic coat layer, or the like can be used.

[0025] As the inorganic vapor deposition layer, for example, a silica vapor deposition film, an aluminum vapor deposition film, an alumina vapor deposition film, or a silica-alumina vapor deposition film can be used.

[0026] As the metal foil layer, for example, metal foils such as aluminum foil, copper foil, and titanium foil, and alloy foils such as aluminum alloy foil and stainless steel foil can be used.

[0027] As the organic coating layer, for example, a vinylidene chloride coating layer or a polyvinylidene fluoride coating layer can be used.

[0028] When an inorganic vapor deposition film or an organic coating layer is used as the barrier layer, the thickness of the barrier layer is preferably 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 from the viewpoint of ensuring strength and barrier properties, and is preferably 5 μm or less, 4 μm or less, 3 μm or less, or 2 μm or less from the viewpoint of improving the handleability as a lid material.

[0029] When a metal foil layer is used as the barrier layer, the thickness of the barrier layer is preferably 3 μm or more, 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, and is preferably 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 as a lid material.

[0030] (Paper layer) The paper layer may be, for example, a layer facing the outside of the lid material. As the paper layer, coated paper, art paper, etc. may be used. Further, the paper layer may be printed by gravure printing, flexographic printing, etc.

[0031] (Other resin layer) The other resin layer may be, for example, a resin layer facing the outside of the lid material. As such a resin layer, the resins mentioned for the base resin layer can be used.

[0032] (Adhesive layer) The adhesive layer can be an optional adhesive layer existing between the above-mentioned layers constituting the base layer. Such an adhesive layer may be, for example, a dry laminate adhesive, a hot melt adhesive, a water-soluble adhesive, an emulsion adhesive, a non-solvent laminate adhesive, and a thermoplastic resin for extrusion lamination, etc.

[0033] 〈Adhesive layer〉 The adhesive layer contains a urethane-based adhesive and a tackifier.

[0034] The ratio of the mass of the urethane-based adhesive to the total mass of the urethane-based adhesive and the tackifier may be, for example, 0.30 or more and 0.95 or less. This ratio may be 0.30 or more, 0.40 or more, or 0.50 or more, and may also be 0.95 or less, 0.90 or less, 0.85 or less, 0.80 or less, or 0.75 or less. In particular, it is preferable that this ratio is 0.50 or more from the viewpoint of improving the initial opening strength. Also, it is preferable that this ratio is 0.75 or less from the viewpoint of improving the opening strength at the time of resealing.

[0035] (Urethane-based adhesive) As the urethane-based adhesive, any commercially available urethane-based adhesive can be used as the "urethane-based adhesive" and the "urethane-based pressure-sensitive adhesive" (urethane-based pressure-sensitive adhesive).

[0036] It is preferable from the viewpoint of resealability that the urethane-based adhesive contains a urethane-urea resin. Here, in the present invention, the "urethane-urea resin" means a polymer having urethane bonds and urea bonds formed by randomly bonding polyamines in which a compound having an isocyanate group, a compound having a hydroxyl group, and a compound having an amino group are condensed via urethane bonds and urea bonds.

[0037] A two-component urethane-based adhesive may be used as the urethane-based adhesive. Here, in the present specification, the "two-component urethane-based adhesive" means a reaction-curing type urethane-based adhesive composed of a main agent and a curing agent.

[0038] When the urethane-based adhesive is a two-component urethane-based adhesive, the ratio of the curing agent to 100 parts by mass of the main agent constituting the two-component urethane-based adhesive may be 1.0 part by mass or more and 8.0 parts by mass or less. This ratio may be 1.0 part by mass or more, 2.0 part by mass or more, or 2.5 part by mass or more, and may also be 8.0 parts by mass or less, 7.0 parts by mass or less, 6.0 parts by mass or less, 5.0 parts by mass or less, 4.0 parts by mass or less, or 3.5 parts by mass or less.

[0039] (Two-component urethane-based adhesive: main agent) The main agent constituting the two-component urethane-based adhesive contains a polyol. Although not particularly limited, from the viewpoint of handleability, those that are liquid at normal temperature are preferred. For example, polyols and polyamines can be mentioned. The main agent may be used alone or in combination of two or more types. In particular, from the viewpoint of obtaining an adhesive layer containing a urethane-urea resin, it is preferable that the main agent is a mixture of a polyol and a polyamine. Further, the main agent may further contain a prepolymer having a hydroxyl group and / or an amino group at the terminal.

[0040] Examples of the polyol include polycarbonate polyol, polycaprolactone polyol, polyester polyol, polyether polyol, polyolefin polyol, acrylic polyol, silicone polyol, castor oil-based polyol, fluorine-based polyol, and the like.

[0041] Among them, polyester polyol or polyether polyol is preferably used, and more preferably at least one polyol selected from the group consisting of polyester polyurethane polyol and polyether polyurethane polyol from the viewpoint of rapid curing.

[0042] In particular, a polyether polyol capable of forming an ether-based resin layer is suitable, and the polyether polyol may be a polyether polyurethane polyol.

[0043] As the polyamine, aliphatic polyamines, alicyclic polyamines, etc. can be used.

[0044] As the aliphatic polyamine, 1,2-diaminoethane (ethylenediamine), 1,3-diaminopropane, 1,4-diaminobutane (1,4-tetramethylenediamine), 1,5-diaminopentane (1,5-pentamethylenediamine), 2-methyl-1,5-pentanediamine, 1,6-diaminohexane (1,6-hexamethylenediamine), 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,12-diaminododecane, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, tetramethylenediamine, 1,2,3-triaminopropane, triaminohexane, triaminononane, triaminododecane, 1,8-diamino-4-aminomethyloctane, 1,3,6-triaminohexane, 1,6,11-triaminoundecane, 3-aminomethyl-1,6-diaminohexane, diethylenetriamine, triethylenetetramine, etc. can be used.

[0045] As the alicyclic polyamine, diaminocyclobutane, isophoronediamine (3-aminomethyl-3,5,5-trimethylcyclohexylamine), 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, methyl-2,4-cyclohexanediamine, methyl-2,6-cyclohexanediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 4,4'-methylenebis(cyclohexylamine), 4,4'-methylenebis(2-methylcyclohexylamine), 2,5-bis(aminomethyl)bicyclo[2,2,1]heptane, 2,6-bis(aminomethyl)bicyclo[2,2,1]heptane, triaminocyclohexane, etc. can be used.

[0046] (Two-component urethane-based adhesive: curing agent) The curing agent constituting the two-component urethane-based adhesive is not particularly limited, but from the viewpoint of handleability, those in a liquid state at normal temperature are preferred. Examples of the curing agent include polyisocyanate.

[0047] Examples of the polyisocyanate include aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanatomethyl caproate; alicyclic diisocyanates such as 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), methyl 2,4-cyclohexane diisocyanate, methyl 2,6-cyclohexane diisocyanate, 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane; aromatic diisocyanates such as m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate or 2,6-tolylene diisocyanate or a mixture thereof, 4,4'-toluidine diisocyanate, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate; aromatic aliphatic diisocyanates such as 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, tetramethylxylylene diisocyanate or a mixture thereof, ω,ω'-diisocyanate-1,4-diethylbenzene; aromatic or aromatic aliphatic organic triisocyanates such as triphenylmethane-4,4'4''-triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene; organic tetraisocyanates represented by aromatic aliphatic tetraisocyanates such as 4,4'-diphenyldimethylmethane-2,2'-5,5'-tetraisocyanate, and polyisocyanate monomers such as these.As the polyisocyanate, derivatives or adducts obtained by reacting these monomers with other compounds, or derivatives such as dimers and trimers derived from these monomers may also be used.

[0048] As the derivative obtained by reacting a polyisocyanate monomer with another compound, it is a reaction product of the above polyol or the above polyamine and the above polyisocyanate, and a urethane prepolymer having isocyanate groups at both ends may be used.

[0049] (Adhesion promoter) As the adhesion promoter, rosin ester, polyterpene, etc. can be used, and among them, using rosin ester is preferable from the viewpoint of adhesiveness.

[0050] Generally, rosin ester is a compound obtained by esterifying rosin.

[0051] The type of resin acid (various isomers) that is the main component of the rosin to be esterified is not particularly limited, and it may be a conjugated resin acid having a conjugated double bond, a non-conjugated resin acid, or a mixture thereof.

[0052] The form of the rosin ester is not particularly limited, and for example, an ester of rosin or polymerized rosin and a polyhydric alcohol, an ester of hydrogenated rosin, or a maleic acid-modified rosin ester obtained by adding maleic acid to the ester may be used. Among them, using a maleic acid-modified rosin ester is preferable from the viewpoint of suppressing glue residue.

[0053] As such a rosin ester, those commercially available as "rosin ester" can be used.

[0054] The softening point of the rosin ester may be, for example, 70°C or higher and 200°C or lower. This softening point may be, for example, 70°C or higher, 80°C or higher, 90°C or higher, 100°C or higher, 110°C or higher, 120°C or higher, or 125°C or higher, and may also be 200°C or lower, 190°C or lower, 180°C or lower, 170°C or lower, 160°C or lower, 150°C or lower, or 145°C or lower. Here, the softening point is measured by the ring and ball method in accordance with JIS K 5601-2-2.

[0055] 〈Heat-sealing layer〉 The heat-sealing layer is a layer containing a polyethylene-based resin. The heat-sealing layer is a layer that can be heat-sealed to an adherend at at least a part thereof, and when a part of the composite film other than the heat-sealing layer is pinched and the composite film is peeled from the adherend, the heat-sealing layer can be broken.

[0056] As the polyethylene-based resin, the polyethylene-based resins mentioned for the base material layer can be used. Among them, it is preferable to use medium-density polyethylene or high-density polyethylene from the viewpoint of facilitating the breakage of the heat-sealing layer.

[0057] The heat-sealing layer may not contain polyolefin-based resins other than polyethylene-based resins, such as polypropylene-based resins and polybutene-based resins.

[0058] In the present invention, the density may be a value measured in accordance with JIS K7112-1999. The density of the heat-sealing layer is 0.920 g / cm 3 or more and 0.965 g / cm 3 or less. This density is 0.920 g / cm 3 or more, 0.923 g / cm 3 or more, 0.925 g / cm 3 or more, 0.927 g / cm 3 or more, 0.930 g / cm 3 or more, 0.933 g / cm 3 or more, or 0.935 g / cm 3 or more, and may also be 0.960 g / cm 3 or less, 0.958 g / cm3 Below, 0.955g / cm 3 Below, 0.952g / cm 3 Below, 0.950g / cm 3 or less than 0.948g / cm 3 In addition, when the polyethylene resin layer is a mixed resin layer of high density polyethylene and low density polyethylene, the above density may be a weighted average in which the density of each polyethylene is weighted by the content of each polyethylene.

[0059] In this specification, "at least" and "at most" indicate numerical ranges that include boundary values. In other words, "at least" and "at most" mean "or more than" and "or less than," respectively.

[0060] Among these, the polyethylene resin layer is made of medium density polyethylene, more specifically, a polyethylene having a density of 0.930 to 0.940 g / cm. 3 Polyethylene or high density polyethylene, more specifically having a density of 0.940 g / cm 3 Super 0.965g / cm 3 It is preferable that the film is composed of the following polyethylene from the viewpoint of improving film formability and ease of breaking.

[0061] The thickness of the heat seal layer may be, for example, 1 μm or more, 2 μm or more, or 3 μm or more. From the viewpoint of both ease of breaking and heat sealability, the thickness is preferably 30 μm or less, 25 μm or less, 20 μm or less, 15 μm or less, less than 10 μm, 7 μm or less, 6 μm or less, or 5 μm or less.

[0062] The heat seal layer may be a film made of a polyethylene resin, or may be obtained by extrusion laminating a polyethylene resin onto the adhesive layer.

[0063] (High density polyethylene) In this specification, high-density polyethylene means polyethylene having a density of 0.940 g / cm 3 or more, which 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 if any, or substantially all repeating units are methylene groups. In particular, it has a density of 0.942 g / cm 3 or more, 0.945 g / cm 3 or more, 0.948 g / cm 3 or more, 0.950 g / cm 3 or more, 0.952 g / cm 3 or more, or 0.955 g / cm 3 or more, and substantially has no long-chain branched structure and is obtained by radical polymerization of ethylene by a low-pressure method. This density may be 0.970 g / cm 3 or less, 0.967 g / cm 3 or less, 0.965 g / cm 3 or less, 0.962 g / cm 3 or less, or 0.960 g / cm 3 or less.

[0064] As preferable thermal properties of high-density polyethylene, for example, when its melt mass flow rate is measured in accordance with JIS K6922-1 and -2 and JIS K7210-1 under the conditions of a temperature of 190 °C and a load of 21.18 N, it is preferably 0.1 g / 10 min or more, 0.5 g / 10 min or more, 1.0 g or more, 3.0 g / 10 min or more, or 5.0 g / 10 min or more, and 100 g / 10 min or less, 50 g / 10 min or less, 30 g / 10 min or less, or 20 g / 10 min or less.

[0065] <<Cover Material>> The cover material of the present invention is a cover material composed of the above composite film.

[0066] More specifically, as shown in FIG. 2, the resealable cover material 100 of the present invention includes a base material layer 102, an adhesive layer 104, and a heat seal layer 106 in this order, The base material layer 102 and the heat-sealing layer 106 are adhered to each other by the adhesive layer 104. The adhesive layer 104 contains a urethane-based adhesive and a tackifier, and the heat-sealing layer 106 contains a polyethylene resin.

[0067] As mentioned in the composite film, the lid material of the present invention can be a re-sealable lid material.

[0068] The lid material of the present invention may have a tab for picking up and pulling up at the time of opening.

[0069] The lid material of the present invention can be obtained by punching the above composite film into the shape of a lid material by any means.

[0070] According to the above configuration, the lid material of the present invention can be broken well without providing a cut formed at a depth less than the thickness of the re-sealable lid material from the half-cut line, that is, the surface of the re-sealable lid material, particularly the surface on the heat-sealing layer side, and without providing it along the region intended to be heat-sealed with the container, that is, the region that becomes the flange seal portion. That is, the lid material of the present invention does not need to have a half-cut on the heat-sealing layer side.

[0071] More specifically, when the tab 110 of the re-sealable lid material 100 joined to the flange portion 202 of the container 200 at the flange seal portion 202a is picked up and the re-sealable lid material 100 is pulled up, as shown in FIG. 3(b), the heat-sealing layer 106 breaks at a position corresponding to the outer periphery of the flange seal portion 202a, and the break portion 120a corresponding to this position is exposed. When the re-sealable lid material 100 is further pulled up, the lid material peels off at the interface between the adhesive layer 104 and the heat-sealing layer 106. Subsequently, when the position corresponding to the inner periphery of the flange seal portion 202a is reached, the heat-sealing layer 106 breaks, and the break portion 120b corresponding to this position is exposed.

[0072] That is, as the adhesive layer 104 follows the substrate layer 102 side, the adhesive layer 104 remains on the heat seal layer 106 side.

[0073] In this way, a resealing portion 104a, which is a part of the adhesive layer 104, is exposed. When the resealing portion 104a is pressed against the heat seal layer 106, it can be resealed.

[0074] According to the above configuration, good resealability can be achieved even after the resealing portion 104a is exposed to a high-temperature and high-humidity environment.

[0075] In the resealable lid material, the thickness of the heat seal layer may be, for example, 1 μm or more, 2 μm or more, or 3 μm or more. From the viewpoint of facilitating breakage and heat sealability, this thickness is preferably 12 μm or less, 10 μm or less, 7 μm or less, 6 μm or less, or 5 μm or less.

[0076] 《Container with Lid Containing Contents》 The container with lid containing contents of the present invention comprises a container having a storage portion and a flange portion, contents accommodated in the container, the above-described lid material, and is provided with the heat seal layer is heat-sealed to the flange portion to form a resealable joint portion.

[0077] 〈Container〉 The container is a container having a storage portion and a flange portion.

[0078] The container is not particularly limited as long as it can heat-seal the lid material. As the container, for example, a paper container whose surface is coated with a resin, or a resin container can be used. In particular, at least the flange portion of the container may be a paper cup coated with a polyethylene-based resin.

[0079] (Storage portion) The storage part is the part where the contents are stored. The shape of this part can be, for example, a substantially frustum of a cone shape, a frustum of a polygonal pyramid shape, a rectangular parallelepiped shape, a cube shape, etc.

[0080] (Flange part) The flange part is the peripheral part of the storage part of the container and may be a flange-like part. The shape of the outer periphery of the flange part can be selected according to the shape of the lid material.

[0081] 〈Contents〉 The contents are the contents stored in the storage part. Such contents include, for example, heated foods such as soup, instant noodles, chilled foods, frozen foods, or non-heated foods such as snacks, gummy candies, etc. In particular, when using heated foods as the contents, since steam will be generated after heating, the application of the present invention is particularly beneficial.

Examples

[0082] The present invention will be specifically described by way of examples and comparative examples, but the present invention is not limited thereto.

[0083] 《Preparation of Composite Film》 〈Example 1〉 The following materials were prepared: Paper (basis weight: 65 g / m 2 ): N Coatrap L, manufactured by Nippon Paper Industries Co., Ltd. Aluminum foil (thickness 7 μm): 1N30, foil manufactured by UACJ Corporation Dry laminating adhesive: Takelac A-525 / Takenate A-52, manufactured by Mitsui Chemicals, Inc. PET (thickness 12 μm): PETB, manufactured by Unitika Ltd. Adhesive layer: A composition composed of 9 parts by mass of a two-component urethane-based adhesive containing a urethane urea resin (main component: curing agent = 1:0.03) and 1 part by mass of maleic acid-modified rosin ester (softening point 130 - 140 °C). Heat seal layer (thickness 7 μm): HDPE film (LW13D, manufactured by Tosoh Corporation, density 0.956 g / cm 3 )

[0084] The composite film obtained as the lid material in this example had a layer structure of paper (basis weight: 65 g / m 2 ) / / aluminum foil (7 μm) / / PET (12 μm) / adhesive layer / heat-sealing layer (where " / / " represents a dry laminate adhesive).

[0085] 1. Using a dry laminator, an aluminum foil "1N30" as the barrier layer and a PET film "PETB" as the base resin layer were adhered via a dry laminate adhesive "Takelac A-525 / Takenate A-52" as the adhesive layer to obtain a member a (aluminum foil (7 μm) / / PET (12 μm)) as the base layer.

[0086] 2. Using a dry laminator, the aluminum foil side of member a and paper "NM Art" as the paper layer were adhered via a dry laminate adhesive "Takelac A-525 / Takenate A-52" as the adhesive layer to obtain a member b (paper (basis weight: 65 g / m 2 ) / / aluminum foil (7 μm) / / PET (12 μm)) as the base layer.

[0087] 3. The above composition as the adhesive layer was coated on the PET film "PETB" side of member b so that the thickness of the adhesive layer was 4 μm to produce a member c (paper (basis weight: 65 g / m 2 ) / / aluminum foil (7 μm) / / PET (12 μm) / adhesive layer).

[0088] 4. A resin as the heat-sealing layer was extrusion-laminated on the adhesive layer of member c to a thickness of 5 μm to obtain a member d (paper (basis weight: 65 g / m 2 ) / / aluminum foil (7 μm) / / PET (12 μm) / adhesive layer / heat-sealing layer) as the laminate constituting the lid material.

[0089] 5. Member d was cut out into a circular shape as shown in Figure 2 to produce the lid material of Example 1.

[0090] 6. The produced lid material was heat-sealed to a PE-coated paper cup (flange width: 3 mm, opening inner diameter: 90 mm) using a heated heat-sealing bar under the conditions of a heat-sealing width of 3 mm, a pressure of 65 Mpa, and a time of 0.7 seconds to obtain a container with a lid.

[0091] Also, for the evaluation of the initial interlayer strength and resealing peel strength mentioned below, the above member d was cut into rectangles with a width of 15 mm × 150 mm, which was used as a laminated body for evaluation.

[0092] 〈Examples 2 to 5 and Comparative Examples 1 to 4〉 Composite films of Examples 2 to 6 and Comparative Examples 1 to 4 were produced in the same manner as in Example 1, except that the composition of the adhesive layer was changed as shown in Table 1.

[0093] 《Evaluation》 〈Initial Interlayer Strength〉 The above laminated body for evaluation was heat-sealed to a polyethylene film under the conditions of a temperature of 150°C, a pressure of 3 kgf / cm -2 , and a time of 1.5 seconds. Then, the portion corresponding to the heat-sealed portion was peeled off at 180° using a measuring instrument (Strograph VES1D, manufactured by Toyo Seiki Seisakusho Co., Ltd.) under the conditions of 300 mm / min and a peel length of 35 mm. At this time, the initial interlayer strength between the base material layer and the adhesive layer was calculated by calculating the average peel strength at a peel length of 10 to 30 mm of the portion corresponding to the heat-sealed portion.

[0094] 〈Flange Glue Remainder〉 The lid material of the produced container with a lid was opened about 1 / 3, 90°C hot water was poured in, and the lid was pressed with a finger. Then, after sealing the lid material for 5 minutes and opening it again, the presence or absence of tack on the flange of the container was confirmed with a finger.

[0095] The evaluation criteria are as follows. A: There was no tack at the flange portion. B: There was weak tack at the flange portion. C: There was strong tack at the flange portion.

[0096] <Peel strength after resealing at 50°C environment> Regarding the sample for which the above initial interlayer strength was calculated, the base material layer and the adhesive layer were overlapped, and a load was applied in the thickness direction of the laminated body for evaluation by reciprocating once with a 2 kg roller to re-bond the base material layer to the adhesive layer. Then, in an environment at a temperature of 50°C, the average peel strength at a peel length of 10 to 30 mm was calculated when the adhesive layer was peeled from the base material layer at 180° under the conditions of 300 mm / min and a peel length of 35 mm from the short side to the long side direction, thereby obtaining the peel strength after resealing.

[0097] <Resealability after pouring hot water> The prepared container with a lid was opened until 1 / 3 of the flange portion of the container was exposed, and 90°C hot water was poured into the container. Next, the base material layer and the adhesive layer were overlapped and resealed by pressing with a finger. It was measured for 5 minutes from the time of resealing, and whether the lid material opened during that time was visually observed.

[0098] The evaluation criteria are as follows: A: The lid material did not open for 5 minutes from the time of resealing. B: The lid material opened within 5 minutes from the time of resealing.

[0099] <Breakability> The prepared container with a lid was opened, and it was visually observed whether breakage of the heat seal layer and the adhesive layer occurred at the position corresponding to the flange seal portion after opening.

[0100] The evaluation criteria are as follows: A: Breakage of the heat seal layer and the adhesive layer occurred at the position corresponding to the flange seal portion. B: Breakage of the heat seal layer and the adhesive layer did not occur stably at the position corresponding to the flange seal portion, and a part of the layer remained beyond this position.

[0101] The configurations and evaluation results of the examples and comparative examples are shown in Table 1.

[0102]

Table 1

[0103] From Table 1, it can be understood that the composite film of the example in which the adhesive layer contains a urethane-based adhesive and a tackifier has appropriate initial unsealing strength and resealability, and furthermore, when peeled from the adherend, the residue on the adherend can be suppressed.

Explanation of Reference Numerals

[0104] 100 Composite film (lid material) 102 Base material layer 104 Adhesive layer 104a Reseal portion 106 Heat seal layer 110 Tab 120a, 120b Breaking portion 200 Container 202 Flange portion 202a Flange seal portion 250 Contents 300 Container with lid containing contents

Claims

1. It includes a base material layer, an adhesive layer, and a heat-sealing layer in this order, The base material layer and the heat-sealing layer are adhered to each other by the adhesive layer, The adhesive layer contains a urethane-based adhesive and an adhesion promoter, and The heat-sealing layer contains a polyethylene resin, A composite film.

2. The ratio of the mass of the urethane-based adhesive to the mass of the urethane-based adhesive and the adhesion promoter is 0.5 to 0.

9. The composite film according to Claim 1.

3. The urethane-based adhesive contains a urethane-urea resin. The composite film according to Claim 1 or 2.

4. The adhesion promoter is a rosin ester. The composite film according to Claim 1 or 2.

5. The thickness of the adhesive layer is 5 μm or less. The composite film according to Claim 1 or 2.

6. The heat-sealing layer does not contain a polypropylene-based resin and a polybutene-based resin. The composite film according to Claim 1 or 2.

7. The heat-sealing layer is a polyethylene resin layer with a density of 0.920 g / cm ３ or more and 0.965 g / cm ３ or less. The composite film according to Claim 1 or 2.

8. The heat-sealing layer is composed of high-density polyethylene with a density exceeding 0.940 g / cm ３ and 0.965 g / cm ３ or less. The composite film according to Claim 1 or 2.

9. A lid material composed of the composite film according to Claim 1 or 2.

10. It is for resealing. The lid material according to Claim 9.

11. The lid material according to claim 9, which does not have a half cut on the heat seal layer side.

12. A container having a storage portion and a flange portion, Contents accommodated in the container, The lid material according to claim 9, and comprising: wherein the heat seal layer is heat sealed to the flange portion to form a resealable joint. A container with a lid containing contents.

13. The container with a lid containing contents according to claim 12, wherein the contents are food.

Images