JP2024008560A - Resealable heat-seal laminate and resealable packaging container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resealable heat-seal laminate and a resealable packaging container that are configured to, when a lid material is peeled off the container, prevent a part of a heat-seal resin layer from remaining on a heat-sealed part on the lid material side or being pulled out stringily (trailing threads), exhibit sufficient initial opening strength, be resealable with practically sufficient strength by pressing the lid material and the container together even after opened, cause no bleeding of liquid components on a laminate surface even after the elapse of time, and cause no loss of reopening strength.

SOLUTION: The resealable heat-seal laminate comprises a substrate (A), an adhesive layer (B) and a heat-seal resin layer (C) in this order. The adhesive layer (B) contains an acrylic copolymer (D). The heat-seal resin layer (C) contains a polyethylene-based resin and also at least one of a polypropylene-based resin and a polybutene-based resin.

SELECTED DRAWING: None

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a resealable heat seal laminate. Furthermore, the present invention relates to a resealable packaging container provided with the resealable heat seal laminate.

Conventionally, plastic containers such as polyethylene containers, polypropylene containers, polystyrene containers, and paper containers coated with polyethylene resin have been used as packaging containers for cup noodles, cup soups, snack foods, and frozen desserts such as yogurt and jelly. , containers made of metal such as iron or aluminum are used. The lid material for these containers usually uses a laminate that uses an adhesive resin layer (heat seal resin layer) that exhibits adhesive properties by heat sealing on the surface that is bonded to the container body. Examples of the structure of this laminate include paper/polyethylene film/aluminum foil/polyethylene film/heat seal resin layer, polyethylene terephthalate (PET) film/aluminum foil/polyethylene film/heat seal resin layer, and the like. In the lid material of the above configuration example, since the heat-sealing resin layer was adhered to the container body by heat sealing (thermal fusion), once it was peeled off, it could not be adhered to the container body again.

In order to re-preserve leftover food, there is a demand in the market for lids and packaging containers that have the property of being able to be re-attached once opened (hereinafter also referred to as resealability). has been considered. A lid material that can be resealed using a multilayer film provided with a layer having resealability has been disclosed.

Specifically, Patent Document 1 discloses a multilayer film lid material consisting of a base material/hot melt adhesive/hot melt adhesive. By heat-sealing this to a paper container coated with polyethylene resin, sealing properties are obtained, and when the lid material is peeled off, there is no breakage or stringiness, and the hot melt adhesive layer is exposed and reused. A sealable lid material has been proposed.

Patent Document 2 discloses a lid with excellent productivity and high resealing strength by coextrusion laminating an adhesive layer consisting of a styrene monomer, a styrene block copolymer, a tackifier, and a sealant layer to a base material in this order. material has been proposed.

However, since the lidding materials described in Patent Document 1 and Patent Document 2 contain liquid components such as mineral oil and styrene monomer, they may bleed into the hot melt adhesive layer and sealant layer over time depending on the storage environment. There was a problem in that the resealing strength decreased.

Japanese Patent Application Publication No. 2013-082914 JP2018-051926A

The present invention was made in view of the above-mentioned problems, and when the lid material is peeled off from the container, a part of the heat-sealed resin layer may remain on the heat-sealed part of the lid material side or be pulled out in the form of threads ( It has sufficient initial opening strength to resist stringing (stringing), and can be resealed with sufficient strength for practical use by pressing the lid and container after opening, and there is no bleeding of liquid components on the surface of the laminate over time. The object of the present invention is to provide a resealable heat-sealable laminate and a resealable packaging container that do not reduce resealing strength.

As a result of intensive studies to solve the above problems, the inventors of the present invention found that
A laminate in which a base material (A), an adhesive layer (B), and a heat-sealing resin layer (C) are arranged in this order, and the adhesive layer (B) is made of an acrylic copolymer (D). Contains
The heat-sealing resin layer (C) contains a polyethylene resin and further contains at least one of a polypropylene resin and a polybutene resin.
We have found that the above problems can be solved by creating a resealable heat-sealable laminate.

That is, the present invention is a laminate in which a base material (A), an adhesive layer (B), and a heat-sealing resin layer (C) are sequentially laminated,
The adhesive layer (B) contains an acrylic copolymer (D),
The heat-sealing resin layer (C) contains a polyethylene resin and further contains at least one of a polypropylene resin and a polybutene resin.
The present invention relates to a resealable heat-sealable laminate.

The present invention relates to a resealable heat-sealable laminate in which the adhesive layer (B) further contains a curing agent (E).

The present invention relates to a resealable heat-sealable laminate in which the adhesive layer (B) further contains a tackifier (F).

The present invention relates to a resealable heat-sealable laminate, wherein the tackifier (F) includes a rosin-based tackifier (F1) or a terpene-based tackifier (F2).

The present invention relates to a resealable packaging container comprising the resealable heat seal laminate and a container body.

With the laminate of the present invention, when the lid material is peeled off from the container, a part of the heat-sealed resin layer does not remain on the heat-sealed part of the lid material side or is difficult to be pulled out in the form of threads (stringing). In addition to exhibiting opening strength, it is possible to reseal with sufficient strength for practical use by pressing the lid and container even after opening, and there is no bleeding of liquid components on the surface of the laminate over time, making it possible to reseal without decreasing resealing strength. A sealable heat seal laminate as well as a resealable packaging container can be obtained.

Before describing the present invention in detail, some terms will be defined. Sheet, film and tape are synonyms. (Meth)acrylic acid includes acrylic acid and methacrylic acid. (Meth)acrylate includes acrylate and methacrylate. The monomer is an ethylenically unsaturated double bond containing monomer.
Further, in this specification, a numerical range specified using "~" includes the numerical values written before and after "~" as the lower limit value and upper limit value range.

The resealable heat-sealable laminate of the present invention includes a base material (A), an adhesive layer (B), and a heat-sealable resin layer (C) arranged in this order. The heat-sealing resin layer (C) develops adhesive properties by applying heat, and can be bonded to the container body. Thereafter, the container can be opened by peeling off the laminate of the present invention from the container. At this time, the heated and bonded portion of the heat-sealing resin layer (C) is designed to transfer to the container side and peel off between the layer and the adhesive layer (B). Therefore, in the peeled off laminate, the adhesive layer (B) is exposed (limited to the portion heat-sealed to the container), and the heat-sealing resin layer (C) is transferred to the container. When the container is resealed, the exposed adhesive layer (B) and the heat-sealing resin layer (C) transferred to the container come into contact, causing a gap between the adhesive layer (B) and the heat-sealing resin layer (C). Appropriate adhesive strength is developed. The laminate of the present invention has a resealing function due to such a mechanism.

<Base material (A)>
The base material (A) in the present invention may be any material as long as it can support the adhesive layer (B) and the heat-sealing resin layer (C), and paper, plastic film, metal foil, etc. can be used. Examples of plastic films include polyester resin films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; fluorine resin films such as polyvinyl fluoride, polyvinylidene fluoride film, polytetrafluoroethylene film, and ethylene-tetrafluoroethylene copolymer film. acrylic film; cellulose-based films such as triacetylcellulose film. Among these, polyester resin films are preferred from the viewpoints of film rigidity, water vapor and oxygen barrier properties, and cost, and polyethylene terephthalate (also referred to as "PET") films are more preferred. Examples of the metal foil include aluminum foil. These base materials may be used in a single layer, or may be laminated into two or more layers using an adhesive or the like. Further, the base material may include an inorganic layer on which a metal oxide or a non-metallic inorganic oxide is deposited or sputtered.

The thickness of the base material (A) is not particularly limited as long as it can be used as a lid material, but it is preferably 10 to 1000 μm.

<Adhesive layer (B)>
The adhesive layer (B) of the present invention is formed by applying an adhesive containing the acrylic copolymer (D) to the base material (A) and drying the solvent such as water or solvent as necessary. I can do things. The adhesive and the acrylic copolymer (D) may or may not contain water or a solvent as a solvent.

[Acrylic copolymer (D)]
The acrylic copolymer (D) can be obtained by polymerizing monomers using a radical polymerization initiator according to a conventional method. The polymerization method is not particularly limited, but when a solvent is used, it is preferable to use solution polymerization. When water is used as a solvent, it is preferable to use emulsion polymerization because a resin dispersion with a high molecular weight, low viscosity, and high solid content can be easily obtained. Examples of monomers include (meth)acrylate monomers, hydroxyl group-containing monomers, carboxyl group-containing monomers, amide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, aromatic ring-containing monomers, alicyclic hydrocarbon group-containing monomers, Examples include vinyl ester.

(Meth)acrylate monomers include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, 2 - Ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n -dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, and the like. Among these, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate are preferred.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

Examples of the carboxyl group-containing monomer include maleic acid, fumaric acid, itaconic acid, citraconic acid, alkyl or alkenyl monoesters thereof, acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, and the like.

Examples of amide group-containing monomers include (meth)acrylamide, N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N'-methylenebisacrylamide, N-methylol (meth)acrylamide, N-ethylol (meth)acrylamide, N-methoxyethyl (meth)acrylamide, N-vinylpyrrolidone, diacetone acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, (meth)acryloyl Examples include morpholine and the like.

Examples of the amino group-containing monomer include N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate.

Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate, methylglycidyl (meth)acrylate, and allylglycidyl ether.

Examples of the aromatic ring-containing monomer include phenyl acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, biphenyl (meth)acrylate, styrene, vinyltoluene, and α-methylstyrene.

Examples of the alicyclic hydrocarbon group-containing monomer include cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and isobornyl (meth)acrylate.

Examples of the vinyl ester include vinyl acetate, vinyl propionate, vinyl laurate, and the like.

The number of monomers constituting the acrylic copolymer (D) may be one type, or two or more types may be used in combination. Among these, it is preferable to contain a (meth)acrylate monomer and further contain at least one of a hydroxyl group-containing monomer and a carboxyl group-containing monomer. When a (meth)acrylate monomer is included, it is preferably contained in 30 to 99 parts by mass out of 100 parts by mass of the total monomer. When at least one of a hydroxyl group-containing monomer and a carboxyl group-containing monomer is included, the total amount of these monomers is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the total monomer.

As the radical polymerization initiator used in the polymerization reaction, known oil-soluble polymerization initiators and water-soluble polymerization initiators can be used, and these may be used alone or in combination of two or more. You may also use it.

The oil-soluble polymerization initiator is not particularly limited, and examples thereof include benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl hydroperoxide, tert-butyl peroxy (2-ethylhexanoate), and tert-butyl peroxide. Organic peroxides such as oxy-3,5,5-trimethylhexanoate, di-tert-butyl peroxide, dilauroyl peroxide;
2,2'-azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 1,1 Examples include azobis compounds such as '-azobis-cyclohexane-1-carbonitrile;

In emulsion polymerization, it is preferable to use a water-soluble polymerization initiator, and examples of the water-soluble polymerization initiator include ammonium persulfate (APS), sodium persulfate (NPS), potassium persulfate (KPS), hydrogen peroxide, Conventionally known compounds such as 2,2'-azobis(2-methylpropionamidine) dihydrochloride can be suitably used.

[Reducing agent]
Furthermore, in emulsion polymerization, a reducing agent may be used in combination with a polymerization initiator. By using a reducing agent in combination, the rate of emulsion polymerization can be accelerated and emulsion polymerization can be easily carried out at low temperatures. Examples of reducing agents include reducing organic compounds such as metal salts such as ascorbic acid, ersorbic acid, tartaric acid, citric acid, glucose, formaldehyde sulfoxylate, Rongalite, and thiourea dioxide;
Reducing inorganic compounds such as sodium thiosulfate, sodium sulfite, sodium bisulfite, sodium metabisulfite, ferrous chloride;
can be mentioned.

[Basic compound]
During monomer polymerization, a basic compound may be used as a neutralizing agent in order to increase the stability of the acrylic copolymer (D). Examples of the basic compound include aqueous ammonia;
Various organic amines such as dimethylaminoethanol, diethanolamine, triethanolamine;
Inorganic alkaline agents such as alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, and potassium hydroxide;
From the viewpoint of water resistance, ammonia water is preferable.

The glass transition temperature (Tg) of the acrylic copolymer (D) is preferably -80 to -10°C, more preferably -75 to -20°C, even more preferably -70 to -30°C. When the glass transition temperature is within this range, the adhesive strength of the adhesive can be increased. Although the glass transition temperature may be two or more, it is preferable that at least one of them is within the above range.
Note that the glass transition temperature in the present invention refers to the glass transition temperature measured by differential scanning calorimetry (DSC) of a resin that has been dried to a nonvolatile content of 100% by mass.
For example, the glass transition temperature can be determined by setting an aluminum pan containing a weighed sample of about 10 mg and an aluminum pan containing no sample in a DSC apparatus, and then measuring the temperature at -100 by using liquid nitrogen in a nitrogen stream. The sample is rapidly cooled to 0.degree. C., then heated to 200.degree. C. at a rate of 20.degree. C./min, and a DSC curve is plotted. The slope of the straight line extending the low-temperature side baseline of this DSC curve (the part of the DSC curve in the temperature range where no transition or reaction occurs in the test piece) to the high-temperature side and the curve of the stepped change part of the glass transition are maximum. The extrapolated glass transition start temperature (Tig) can be determined from the intersection with the tangent line drawn at such a point, and this can be determined as the glass transition temperature.

The weight average molecular weight (Mw) of the acrylic copolymer (D) is preferably 50,000 to 2,000,000, more preferably 100,000 to 1,500,000, 300,000 to 1,000, 000 is more preferred. When the weight average molecular weight is within this range, the adhesive strength of the adhesive becomes higher.
Note that the weight average molecular weight is a polystyrene equivalent value determined by gel permeation chromatography (GPC) of the resin. For example, the temperature of the column (KF-805L, KF-803L, and KF-802 manufactured by Showa Denko K.K.) was set to 40°C, THF (tetrahydrofuran) was used as the eluent, and the flow rate was set to 0.2 ml/min. It can be measured using RI, sample concentration of 0.02% by mass, and polystyrene as a standard sample.

Note that if the weight average molecular weight of the acrylic copolymer (D) is large, it may not dissolve in THF, which is the eluent. In such a case, since measurement is not possible, the weight average molecular weight is determined to be greater than 2,000,000.

When using a solvent for the adhesive or acrylic copolymer (D), examples of the solvent include alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol methyl ether, and diethylene glycol methyl ether; acetone, methyl ethyl ketone, and methyl isobutyl ketone. Ketones such as , cyclohexanone; Ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether; Hydrocarbons such as hexane, heptane, octane; Aromatics such as benzene, toluene, xylene, cumene; Esters such as ethyl acetate, butyl acetate ; etc.

Note that the acrylic copolymer (D) can be used without containing water or solvent, but in that case, it is preferable that the acrylic copolymer (D) is a block copolymer. A block copolymer is, for example, a polymer block containing a structural unit derived from an alkyl methacrylate having an alkyl group of 1 to 3 carbon atoms and a structure derived from an alkyl acrylate having an alkyl group of 1 to 8 carbon atoms. Acrylic copolymers having polymer blocks containing units can be used. By using such a block copolymer, the cohesive force within the acrylic copolymer (D) is increased, and the effect of improving adhesive strength can be expected.

The block copolymer is formed from a hard segment (AH) formed from an alkyl methacrylate ester in which the alkyl group has 1 to 3 carbon atoms, and an alkyl acrylate ester in which the alkyl group has 1 to 8 carbon atoms. Examples include a triblock polymer in which a soft segment (AS) is bonded to -AH-AS-AH-, a diblock polymer in which a soft segment (AS) is bonded to -AS-AH-, and the like. A triblock polymer and a diblock polymer may be used together.

As the methacrylic acid alkyl ester having an alkyl group having 1 to 3 carbon atoms for forming the hard segment of the block copolymer, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, and isopropyl methacrylate are preferable.
Examples of acrylic acid alkyl esters having an alkyl group having 1 to 8 carbon atoms for forming the soft segment of the block copolymer include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, and acrylic acid. Examples include n-butyl, isobutyl acrylate, isoamyl acrylate, hexyl acrylate, and 2-ethylhexylate acrylate.

Specific examples of the block copolymer include Clarity LA2140E (, Clarity LA2250, Clarity LA2330, Clarity LA3320, Clarity LA3170, Clarity LA2270, Clarity LA4285, Clarity LA1892, Clarity LK9243, Clarity KL-LK9333, etc.

The adhesive layer (B) contains an acrylic copolymer (D), and may contain a curing agent (E) and a tackifier (F) as necessary.

[Curing agent (E)]
Examples of the curing agent (E) include isocyanate curing agents, epoxy curing agents, aziridine curing agents, and chelate type curing agents.

As the isocyanate curing agent, diisocyanate or polyisocyanate having a trifunctional or higher functional isocyanate group obtained by modifying diisocyanate is preferred.
Examples of diisocyanates include aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates.
Aromatic diisocyanates include, for example, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzylisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, Examples include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, and tolylene diisocyanate.
Examples of aliphatic diisocyanates include butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, m-tetramethylxylylene diisocyanate, and the like. It will be done.
Examples of alicyclic diisocyanates include cyclohexane-1,4-diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, and the like. Can be mentioned.

The polyisocyanate is preferably a so-called adduct obtained by modifying a diisocyanate with a trifunctional polyol component, a burette obtained by reacting a diisocyanate with water, or a trimer having an isocyanurate ring formed from three molecules of diisocyanate (isocyanurate). Examples of the polyisocyanate include a trimethylolpropane adduct of xylylene diisocyanate, a trimethylolpropane adduct of tolylene diisocyanate, a burette of hexamethylene diisocyanate, an allophanate of hexamethylene diisocyanate, an isocyanurate of isophorone diisocyanate, and the like. .

Examples of the epoxy curing agent include 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-m-xylylenediamine, ethylene glycol diglycidyl ether, Examples include 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidylaniline, and diglycidylamine.

Examples of the aziridine curing agent include diphenylmethane-4,4'-bis(1-aziridine carboxamide), trimethylolpropane tri-β-aziridinylpropionate, and tetramethylolmethanetri-β-aziridinylpropionate. , toluene-2,4-bis(1-aziridinecarboxamide), triethylenemelamine, bisisophthaloyl-1-(2-methylaziridine), tris-1-(2-methylaziridine)phosphine, trimethylolpropane Examples include tri-β-(2-methylaziridine)propionate.

Examples of the chelate type curing agent include compounds consisting of a polyvalent metal and a ligand, and examples of the polyvalent metal include nickel, aluminum, chromium, iron, titanium, zinc, cobalt, manganese, and zirconium. Examples of the ligand include acetylacetone and acetoacetate.

When a curing agent is used, its content is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 7.5 parts by mass, and more preferably 0.5 to 7.5 parts by mass, based on 100 parts by mass of nonvolatile content of the adhesive layer. 5 parts by mass is more preferred. When the curing agent is within these ranges, effects such as improved adhesive strength and improved durability can be expected.

[Tackifier (F)]
Examples of the tackifier (F) include rosin-based tackifier (F1), terpene-based tackifier (F2), coumaron-based tackifier, styrene-based tackifier, petroleum-based tackifier, etc. .

Examples of the rosin-based tackifier (F1) include rosin-based resins, polymerized rosin-based resins, rosin ester-based resins, and polymerized rosin ester-based resins. Examples of the terpene tackifier (F2) include terpene resins and terpene phenol resins. When using a tackifier (F), it is preferable to include a rosin-based tackifier (F1) or a terpene-based tackifier (F2), and more preferably to include a rosin-based tackifier (F1). By using these tackifiers (F), the effect of improving adhesive strength can be expected.

When using a tackifier (F), its content is preferably 1 to 40 parts by weight, more preferably 5 to 40 parts by weight, and 15 to 30 parts by weight based on 100 parts by weight of nonvolatile content of the adhesive layer. More preferred. By falling within these ranges, it is possible to easily improve the adhesive strength and provide a laminate with excellent resealability.

The adhesive layer of the present invention further includes a flame retardant, a heat stabilizer, a weather stabilizer, an anti-aging agent, an ultraviolet absorber, a leveling agent, an antistatic agent, a slip agent, an anti-blocking agent, an anti-fogging agent, and a lubricant as optional components. , dyes, waxes, etc.

<Heat seal resin layer (C)>
The heat-sealing resin layer (C) contains a polyethylene resin, and further contains at least one of a polypropylene resin and a polybutene resin. Since polyethylene resin is not compatible with polypropylene resin or polybutene resin, incompatible resins coexist in the heat seal resin layer (C).
By the way, as described above, after the heat-sealed resin layer (C) is bonded to the container by heat-pressing, the heat-sealed portion is transferred to the container after the laminate is unsealed. In other words, when opening the package, the heat-sealing resin layer (C) will be torn between the heat-sealed part and the other parts, and if the tearability of the layer is not sufficient, the heat-sealing resin layer (C) will be torn on either the laminate side or the container side. Part (C) may remain partially, or stringiness may occur where it is stretched into a string. By containing a polyethylene resin and at least one of a polypropylene resin and a polybutene resin that are incompatible with the polyethylene resin, tearability is improved and such a phenomenon becomes less likely to occur.

Polyethylene-based resins include, for example, low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymers (EVA), and from the group consisting of ethylene and alkenes of propylene, butene, pentene, hexene, or higher carbon chains. A copolymer consisting of a monomer mixed with at least one selected monomer in an arbitrary ratio can be used. Regarding copolymers of ethylene and propylene and copolymers of ethylene and butene, those in which the content of propylene or butene is less than 50% by mass in 100% by mass of the total monomers are included in polyethylene resins. shall be taken as a thing. Among these, low-density polyethylene and ethylene-vinyl acetate copolymer (EVA) are preferred, and low-density polyethylene is more preferred, from the viewpoint of extrusion lamination processability. Particularly preferred is low-density polyethylene produced by a high-pressure method.

Polypropylene resin is a copolymer consisting of a monomer of propylene, or a mixture of propylene and at least one member selected from the group consisting of ethylene, butene, pentene, hexene, or alkenes with higher carbon chains. Polymers can be used. Regarding copolymers of ethylene and propylene, those containing 50% by mass or more of propylene in a total of 100% by mass of monomers are considered to be included in polypropylene resins. Among these, polypropylene-ethylene copolymer is preferred from the viewpoint of coatability by extrusion lamination.

Examples of the polybutene resin include polymers obtained by homopolymerization or copolymerization of 1-butene, 2-butene, and isobutylene. In addition, a monomer consisting of a mixture of these monomers and at least one selected from the group consisting of ethylene, propylene, pentene, hexene, or an alkene with a carbon chain longer than that in any ratio. Polymers can be used. Regarding copolymers of ethylene and butene, those containing 50% by mass or more of butene in a total of 100% by mass of monomers are considered to be included in polybutene-based resins.
Among these, 1-butene-ethylene copolymer is preferred from the viewpoint of coatability by extrusion lamination.

The melt flow rate (hereinafter referred to as MFR) of the polyethylene resin is preferably 0.1 to 30 g/10 minutes, more preferably 0.1 to 20 g/10 minutes, and even more preferably 0.1 to 10 g/10 minutes. Within the above range, coating by extrusion lamination can be made more stable. In addition, the MFR of polyethylene resin is JIS. This is a value measured under the conditions of 190°C and 21.168N according to K7210.

The MFR of polypropylene resin and polybutene resin is preferably 0.1 to 10 g/10 minutes, more preferably 0.5 to 8 g/10 minutes. Within the above range, coating by extrusion lamination can be made more stable. In addition, the MFR of polypropylene resin and polybutene resin is JIS. This is a value measured under the conditions of 230°C and 21.168N according to K7210.

The content of the polyethylene resin is preferably 35 to 70% by mass, more preferably 40 to 65% by mass, and 45 to 60% by mass based on 100% by mass of the heat seal resin layer (C). Even better. When the polyethylene resin is 35% by mass or more, coating by extrusion lamination can be more stabilized. In addition, when the content is 70% by mass or less, the tearability and adhesiveness of the heat-sealing resin layer (C) can be easily maintained.

The total content of polypropylene resin and polybutene resin is preferably 15 to 40% by mass, more preferably 18 to 35% by mass, and 20% by mass in 100% by mass of the heat seal resin layer (C). More preferably, the amount is 30% by mass. It is preferable that it is within the above range from the viewpoint of tearability of the heat-sealing resin layer (C).

The heat-sealing resin layer (C) may contain other resins and tackifiers within a range that does not impair its performance. Other resins include, specifically, ethylene-unsaturated monocarboxylic acid copolymers such as maleic acid modified products, ethylene-acrylic acid copolymers, ethylene-(meth)acrylic acid copolymers, and metal salts thereof; Examples include various elastomers such as styrene-butadiene copolymer elastomers and hydrogen adducts thereof. The same tackifier as the tackifier (F) that may be included in the adhesive layer (B) can be used as the tackifier. The content of other resins and tackifiers is preferably 15% by mass or less, more preferably 10% by mass or less, and preferably 5% by mass or less in 100% by mass of the heat seal resin layer (C). It is even more preferable.

Wax can be further added to the heat-sealing resin layer (C) in order to improve adhesion to the adhesive layer (B) and improve stringiness. Examples of the wax include polyethylene wax, polypropylene wax, ethylene-vinyl acetate copolymer wax, Fischer-Tropsch wax, paraffin wax, oxidized wax, and maleic acid-modified wax. Among these, polyethylene wax is preferred. When containing wax, the content thereof is preferably 8 to 40% by mass, more preferably 12 to 30% by mass, and 15 to 25% by mass based on 100% by mass of the heat seal resin layer (C). It is more preferable that The viscosity of the wax at 140° C. is preferably 50 to 10,000 mPa·s, more preferably 60 to 8,000 mPa·s. The viscosity is a value measured using a B-type viscometer (measurement conditions: 140° C., rotor No. 3, 12 rpm, 30 seconds).

The heat-sealing resin layer (C) may further contain additives in order to prevent thermal deterioration, thermal decomposition, and blocking, and to provide suitability for film processing and extrusion lamination processing, within a range that does not impair its performance. Examples of additives include organic lubricants such as erucic acid amide, inorganic lubricants such as calcium carbonate, antioxidants such as hindered phenol, other antiblocking agents, antistatic agents, fillers, and pigments. Additives can be mixed, for example, by putting each component used in the heat-sealing resin layer (C) into a mixing device such as a Henschel mixer or a tumbler mixer, mixing for 5 to 20 minutes, then putting it into an extruder and heating it. This is done by pushing out the kneaded mixture. The extrudate is usually formed into pellets for later use. Preferred examples of the extruder include, but are not limited to, a twin-screw extruder. Furthermore, extrusion is usually carried out at 140 to 200°C.

≪Resealable heat seal laminate≫
The resealable heat-sealable laminate of the present invention can be produced by, for example, laminating a heat-sealing resin layer (C) on the adhesive layer (B) of a base material (A) on which an adhesive layer (B) is laminated. It can be obtained by etc.
The adhesive layer (B) can be formed by applying an adhesive onto the base material (A) by a conventionally known coating method, and if water or a solvent is included, further performing a drying step. Examples of coating methods include known coating methods such as spin coating, spray coating, bar coating, knife coating, roll coating, roll knife coating, blade coating, die coating, and gravure coating. Can be used. In the drying process, a known device such as a hot air oven, electric oven, or infrared heater can be used. If the adhesive does not contain water or solvent, the adhesive may be heated to lower its viscosity, applied to the base material (A) using a coating method such as die coating, and then subjected to a cooling process. An example of this method is to form the adhesive layer (B) in the following manner. After forming the adhesive layer (B), you can proceed to the next process as is on the same line, or you can laminate release paper or release film on the adhesive layer (B) and wind it up, and then proceed to the next process on the same line. The release paper or release film may be peeled off to expose the adhesive layer (B) before proceeding to the next step.
As a method for laminating the heat-sealing resin layer (C) on the adhesive layer (B), for example, each component used for the heat-sealing resin layer (C) is mixed, heated and kneaded using an extruder, and then extruded. The material is finely chopped into pellets, and the pellets are used to form a single-layer film using an inflation method or a casting method. Next, a method may be mentioned in which this single layer film is laminated by bonding it onto the adhesive layer (B). Alternatively, the above pellets may be melted and coated directly onto the adhesive layer (B) using a T-die extrusion device.

≪Resealable packaging container≫
The resealable packaging container of the present invention uses the resealable heat-sealable laminate of the present invention as a lid material, is cut to match the opening shape of the container body, and is sealed by heat-pressing and bonding it to the opening of the container body. This is what was done. That is, by bringing the heat sealing resin layer (C) of the resealable heat sealing laminate of the present invention into contact with the adhesive surface (also referred to as a flange) of the opening of the sealed container and heating (heat sealing), Glue both together. The bonding conditions are preferably 130 to 170°C.

As the container main body, a container main body made of polyethylene resin and a container main body whose inner surface is covered with polyethylene resin are preferable.

When the container body is a PET container, it is preferable to thermally bond the container body and the lid material at a thermal bonding temperature of 130 to 170° C., and it is preferable that the opening strength at room temperature is in the range of 10 to 20 N. The resealable packaging container of the present invention can package, for example, jelly, pudding, yogurt, frozen desserts, dried sweets, cup noodles, and the like.

The present invention will be described below based on examples, but the present invention is not limited thereto. In the examples, "parts" and "%" represent "parts by mass" and "% by mass," respectively.

The glass transition temperature and weight average molecular weight of the acrylic copolymer (D) were measured as follows.

<Measurement of glass transition temperature (Tg)>
The glass transition temperature was determined by the differential scanning calorimetry (DSC) method described above.
Note that the sample for Tg measurement used was one obtained by heating the resin solution to be measured at 150° C. for about 15 minutes and drying it.

<Measurement of weight average molecular weight>
The weight average molecular weight was measured by the method described above, and a polystyrene equivalent value determined by gel permeation chromatography (GPC) was used.

<Synthesis of acrylic copolymer (D1)>
Monomers include 3.15 parts of methyl methacrylate, 32 parts of 2-ethylhexyl acrylate, 64 parts of butyl acrylate, 0.85 parts of acrylic acid, and "Aqualon KH-10" (polyoxyethylene-1-(allyloxy 1.0 part of methyl)alkyl ether sulfate ammonium salt (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 25.1 parts of deionized water were added and stirred to obtain an emulsion. The resulting emulsion was placed in a dropping funnel.
Separately, 45.6 parts of deionized water and 1.0 part of the above emulsion were charged into a four-necked flask equipped with a stirrer, a cooling tube, a thermometer, and the above-mentioned dropping funnel, and the inside of the flask was filled with nitrogen gas. The inside temperature was heated to 70°C while stirring. Thereafter, 10% ammonium persulfate was added to start the reaction. The above emulsion was added dropwise over 180 minutes while the internal temperature was maintained at 70°C, and the reaction was continued for 1 hour while the internal temperature was maintained at 70°C with further stirring. Thereafter, the internal temperature was cooled to 65°C, and 1.0 part of a 10% aqueous solution of the oxidizing agent "Perbutyl H-69" (manufactured by Nippon Oil & Fats Co., Ltd.) and the reducing agent "Elvit N" (manufactured by Fuso Chemical Industries, Ltd.) were added. 1.0 part of a 10% aqueous solution was added three times at 10 minute intervals, and the reaction was continued for an additional hour. Thereafter, it was cooled and neutralized by adding 25% ammonia water at 30°C to obtain an acrylic copolymer (D1) solution with a nonvolatile content concentration of 50% and a Tg of -45°C. Since the acrylic copolymer (D1) was not dissolved in THF, the weight average molecular weight was determined to be greater than 2,000,000.

<Synthesis of acrylic copolymer (D2)>
5 parts of methyl methacrylate, 90.5 parts of 2-ethylhexyl acrylate, and 4.5 parts of acrylic acid were used as monomers, and "Hitenol NF-08" (polyoxyethylene alkyl ether sulfate, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was used as an emulsifier. was synthesized in the same manner as the acrylic copolymer (D1) except that acrylic copolymer (D1) was used, and an acrylic copolymer (D1) solution with a nonvolatile content concentration of 50% and a Tg of -46°C was obtained. Since the acrylic copolymer (D1) was not dissolved in THF, the weight average molecular weight was determined to be greater than 2,000,000.

<Synthesis of acrylic copolymer (D3)>
Using a polymerization apparatus equipped with a stirrer, thermometer, dropping tube, and reflux condenser, 1 part of methyl methacrylate, 4 parts of isobutyl methacrylate, 4 parts of vinyl acetate, 85.3 parts of butyl acrylate, 5 parts of 2-methoxyethyl acrylate, Half of the raw material mixture containing 0.7 parts of 2-hydroxyethyl acrylate, 10 parts of methyl ethyl ketone, 60 parts of ethyl acetate, and 0.1 part of benzoyl peroxide was charged into a reaction tank under a nitrogen atmosphere. Separately, the remaining half of the raw material mixture was charged into the dropping layer. Then heating of the reaction vessel was started. After confirming the start of the polymerization reaction, the raw material mixture was added dropwise from the dropping tube over a period of 1 hour. After the dropwise addition was completed, solution polymerization was further continued for 7 hours under reflux. After the reaction was completed, it was cooled to obtain an acrylic copolymer (D3) solution with a nonvolatile content of 58.8%. The obtained acrylic copolymer (D3) had a Tg of -47°C and a weight average molecular weight of 708,000.

<Synthesis of acrylic copolymers (D4) and (D5)>
Acrylic copolymer (D4) and (D5) solutions with a non-volatile content of 58.8% were obtained in the same manner as the synthesis of acrylic copolymer (D3), except that the monomer composition was changed to the composition shown in Table 1. . Their Tg and weight average molecular weight are shown in Table 1.

<Synthesis of acrylic copolymer (D6)>
The non-volatile content was 58 in the same manner as in the synthesis of acrylic copolymer (D3), except that the monomer composition was changed to the composition shown in Table 1, the amount of methyl ethyl ketone used was changed to 7 parts, and the amount of ethyl acetate was changed to 63 parts. A .8% acrylic copolymer (D6) solution was obtained. Tg and weight average molecular weight are shown in Table 1.

<Acrylic copolymer (D7), (D8)>
The following acrylic copolymers (D7) and (D8) were used, respectively.
Acrylic copolymer (D7): Clarity LK9243 (manufactured by Kuraray Co., Ltd., methyl methacrylate-2-ethylhexyl acrylate-methyl methacrylate block copolymer, MFR93g/10min)
Acrylic copolymer (D8): Clarity LA3320 (manufactured by Kuraray Co., Ltd., methyl methacrylate-butyl acrylate-methyl methacrylate block copolymer, MFR6g/10min)
Note that all of the above MFRs are values at 190° C. and a load of 2.16 kg.

In addition, the abbreviations in Table 1 are as follows.
MMA: methyl methacrylate EA: ethyl acrylate 2EHA: 2-ethylhexyl acrylate IBMA: isobutyl methacrylate VAc: vinyl acetate BA: n-butyl acrylate 2MTA: 2-methoxyethyl acrylate AA: acrylic acid 2HEA: 2-hydroxyethyl acrylate

[Example 1: Production of laminate]
<Manufacture of adhesive>
A pressure-sensitive adhesive was produced by blending 79.1 parts of acrylic copolymer D3, 1.1 parts of curing agent E1, and 19.8 parts of tackifier F1-1. However, the ratios in Table 2 indicate solid content ratios.

<Manufacture of single layer film of heat seal resin layer (C)>
53 parts of polyethylene resin PE1, 26 parts of polypropylene resin PP1, and 21 parts of additive C1 were mixed and preblended for 5 minutes using a Henschel mixer. The preblend was placed in a hopper and fed to the extruder described below using a screw feeder to produce a resin mixture for the heat-sealing resin layer (C).
≪Extruder conditions≫
Extruder: Co-rotating twin-screw extruder PMT32-40.5 manufactured by I.K.G.
Barrel temperature: 180℃ (supply port 160℃)
Screw rotation speed: 200rpm
Supply rate: 10kg/hr

The obtained mixture was subjected to inflation molding using an inflation molding machine manufactured by Labtech (Dice diameter: 40 mmφ, molding temperature: 130° C.) to produce a single-layer film of a heat-sealable resin layer (C) having a thickness of 20 μm.
≪Single layer molding conditions≫
Inflation molding machine: Labtech Resin temperature: 130℃
Barrel temperature: 180℃ (supply port 170℃)
Screw rotation speed: 60rpm
Pulling speed: 5m/min Cooling roll surface temperature: 20℃

<Manufacture of laminate>
The obtained adhesive was applied with a roll coater to the corona-treated surface of a 12 μm biaxially stretched PET film as the base material (A), and the solvent was removed in an oven at 100°C to form a 20 μm thick adhesive layer ( B) was formed. Next, a single-layer film of the heat-sealing resin layer (C) is laminated on the surface of the adhesive layer (B) to form the base material (A)/adhesive layer (B)/heat-sealing resin layer (C). A laminate of Example 1 was obtained in which the layers were stacked in order.

In addition, each component in Tables 2 and 3 shows the following.

<Styrenic copolymer (S)>
S1: Kraton G-1657 (manufactured by Kraton Polymer Japan, styrene-ethylene-butadiene-styrene block copolymer, MFR22g/10min)
S2: Kraton G-1652 (manufactured by Kraton Polymer Japan, styrene-ethylene-butadiene-styrene block copolymer, MFR5g/10min)
Note that all of the above MFRs are values at 230°C and a load of 5 kg.

<Curing agent (E)>
E1: Trimethylolpropane adduct of xylylene diisocyanate diluted with ethyl acetate to a nonvolatile content of 50%: Isocyanate curing agent E2: Trimethylolpropane adduct of tolylene diisocyanate diluted with ethyl acetate to a nonvolatile content of 40% Item: Isocyanate curing agent E3: TETRAD-X (manufactured by Mitsubishi Gas Chemical Co., Ltd., multifunctional epoxy resin) diluted with MEK to a non-volatile content of 10%: Epoxy curing agent

<Tackifier (F)>
F1-1: Pine Crystal KE-359 (manufactured by Arakawa Chemical Co., Ltd., rosin derivative)
F1-2: Pencell D-125 (manufactured by Arakawa Chemical Co., Ltd., rosin ester)
F2-1: YS resin PX-1000 (manufactured by Yasuhara Chemical Co., Ltd., terpene resin)
F3: Alcon P-100 (manufactured by Arakawa Chemical Co., Ltd., hydrogenated petroleum resin)
F4: Kristalex F-100 (manufactured by Eastman Chemical Co., styrene-α methylstyrene copolymer)

<Liquid component (L)>
L1: Diana Process PW-32 (manufactured by Idemitsu Kosan, mineral oil)
L2: Styrene monomer (manufactured by Kanto Kagaku Co., Ltd.)

<Other additives (P)>
P1: MS-P (manufactured by Nippon Talc Co., Ltd., inorganic material, average particle size 14 μm)

<Polyethylene resin>
PE1: Petrocene 213 (manufactured by Tosoh Corporation, low density polyethylene, MFR8g/10min)
PE2: Ultracene 526 (manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer, vinyl acetate content 7%, MFR 25g/10min)
Note that all of the above MFRs are values at 190° C. and a load of 2.16 kg.

<Polypropylene resin and polybutene resin>
PP1: SB-520 (manufactured by LOTTE, polypropylene-polyethylene copolymer, MFR1.8g/10min)
PB1: Tafmer BL-4000 (manufactured by Mitsui Chemicals, butene-ethylene copolymer, MFR1.8g/10min)
Note that all of the above MFRs are values at 190° C. and a load of 2.16 kg.

<Additive (C)>
C1: L-C121N (manufactured by LIONCHEMTECH, polyethylene wax, melting point 109°C)

[Example 1: Production of resealable packaging container]
After overlapping the flange (width approximately 4 mm) around the opening of a cylindrical paper container (outer diameter: 95 mmφ) with a polyethylene film laminated on the inside, the sealing temperature was 150°C using MODEL 2005 (manufactured by Towa Techno). The laminate obtained in Example 1 was heat-sealed under the conditions of sealing pressure: 100 kgf/cup and sealing time: 1 second to obtain a resealable packaging container.

(1) Opening strength A resealable packaging container was tested at an opening angle of 90 degrees using a tensile tester (Autograph AGS-X, manufactured by Shimadzu Corporation) in an environment of 23°C and 65% relative humidity (65% RH). The adhesive strength was measured when approximately 50% of the laminate was peeled off at an opening speed of 300 mm/min, and the maximum value was read.
◎: 12N or more and less than 20N: Very good ○: 9N or more and less than 12N, or 20N or more and less than 23N: Good △: 6N or more and less than 9N, or 23N or more and less than 26N: Usable ×: Less than 6N, or 26N or more: Not usable

(2) Stringing After measuring the opening strength of the resealable packaging container, the peeled portion between the laminate and the container was visually observed to confirm the occurrence of stringing.
◎: There is no stringing (the area where stringing occurs is 0% of the area of the peeled part): Very good ○: The area where stringing occurs is larger than 0% of the area of the peeled part 10% or less: Good △: Of the area of the peeled part, the area of the part where stringing occurs is greater than 10% and 30% or less: Usable ×: Of the area of the peeled part, the area of the part where stringy occurs is 30% Greater than %: Unusable

(3) Zipping Occurrence of zipping was confirmed when measuring the opening strength of resealable packaging containers ◎: No zipping (out of the area of the peeled part, the area where zipping occurred is 0%): Very good ○: Peeled Of the area of the part, the area of the part where zipping occurs is greater than 0% and less than 10%: Good △: Of the area of the peeled part, the area of the part where zipping occurs is more than 10% and less than 30%: Usable ×: The area of the area where zipping occurs is larger than 30% of the area of the peeled part: Unusable

(4) Resealing After measuring the unsealing strength of the resealable packaging container, the laminate and the peeled part of the container were placed on top of each other, and the laminate was pressed back and forth with a finger twice to seal it, and then the unsealing strength was measured again. This was repeated five times, and the maximum value was read at the fifth time.
◎: 4N or more and less than 7N: Very good ○: 2N or more and less than 4N, 7N or more and less than 10N: Good △: 1N or more and less than 2N, 10N or more and less than 13N: Usable ×: Less than 1N, or 13N or more: Not usable

(5) Bleeding on the surface of the heat seal resin layer (C) after aging After aging the laminate at 40° C. for 24 hours, it was visually compared with the laminate before aging to confirm changes in the surface condition.
○: No change: Good ×: Surface wet and sticky: Unusable

(6) Resealing after aging The laminate and a cylindrical paper container with a polyethylene film laminated inside were heated in the same manner as above, except that the laminate was aged at 40°C for 24 hours. It was sealed to obtain a resealable packaging container. This resealable packaging container was tested at an opening angle of 90 degrees and an opening speed of 300 mm using a tensile tester (Autograph AGS-X, manufactured by Shimadzu Corporation) in an environment of 23°C and 65% relative humidity (65% RH). About 50% of the laminate was peeled off at 1/min. Next, the unsealed laminate of the resealable packaging container and the peeled portion of the container were placed on top of each other, and the laminate was pressed back and forth with fingers twice to seal it, and then the unsealing strength was measured again. This was repeated 5 times and the maximum value was read at the 5th time. Using this value and the reseal evaluation value when using a laminate that has not been aged, the following relative ratios were determined and evaluated as follows.

Relative ratio (%) = 100 x (reseal evaluation value when using a laminate that has not been aged) / (reseal evaluation value when using a laminate that has been aged at 40°C for 24 hours)

○: Relative ratio 70% or more: Usable ×: Relative ratio less than 70%: Unusable

[Examples 2 to 15]
In Examples 2 to 15, laminates and resealable packaging containers were produced and evaluated in the same manner as in Example 1, except that the composition and ratio of the adhesive were changed as shown in Tables 2 and 3.

[Example 16: Production of laminate]
<Manufacture of adhesive>
In a Henschel mixer, 65 parts of acrylic copolymer D7, 15 parts of tackifier F3, and 20 parts of tackifier F4 were mixed and preblended for 5 minutes. The preblend was placed in a hopper and fed to the extruder described below using a screw feeder to produce an adhesive.
≪Extruder conditions≫
Extruder: Co-rotating twin screw extruder PMT32-40.5 manufactured by IKG Co., Ltd.
Barrel temperature: 180℃ (supply port 160℃)
Screw rotation speed: 200rpm
Supply rate: 10kg/hr

<Manufacture of laminate>
An adhesive is extruded from a T-die to a thickness of 20 μm onto the corona-treated surface of a 12 μm biaxially stretched PET film as a base layer, and at the same time a heat seal resin layer (C) is applied to the surface of the adhesive layer (B). A laminate in which the base material (A)/adhesive layer (B)/heat-sealing resin layer (C) were laminated in this order was obtained by a sandwich lamination method in which monolayer films were laminated.

[Example 16: Production of resealable packaging container]
A resealable packaging container was manufactured and evaluated in the same manner as in Example 1.

[Example 17]
In Example 17, a laminate and a resealable packaging container were produced and evaluated in the same manner as in Example 16, except that the composition and ratio of the adhesive were changed to those shown in Table 3.

[Examples 18-20]
In Examples 18 to 20, laminates and resealable packaging containers were prepared and evaluated in the same manner as in Example 1, except that the composition and ratio of the adhesive and heat seal resin layer (C) were changed as shown in Table 3. did.

[Comparative Example 1: Production of laminate]
<Manufacture of adhesive>
35 parts of liquid component L1 (mineral oil) was added to a stainless steel beaker equipped with a stirrer and heated and stirred to 160°C. While stirring, 30 parts of styrene elastomer S1 and tackifier F3 were blended and stirred for 3 hours to obtain a hot melt adhesive.

<Manufacture of adhesive layer>
A hot melt adhesive heated to 160°C is applied with a hand coater to the corona-treated surface of a 12 μm biaxially stretched PET film as the base material (A) to form a 30 μm thick adhesive layer (B). A laminate of material (A)/adhesive layer (B) was obtained.

<Manufacture of laminate>
A single layer film of the heat-sealing resin layer (C) is laminated on the surface of the adhesive layer (B) of the laminate of the base material (A)/adhesive layer (B), and the base material (A)/adhesive layer A laminate was obtained in which (B)/heat seal resin layer (C) were laminated in this order.

[Comparative Example 1: Production of resealable packaging container]
A cup seal product was produced and evaluated in the same manner as in Example 1.

[Comparative example 2]
A laminate and a cup seal were produced and evaluated in the same manner as in Example 16, except that the composition and ratio of the adhesive were changed as shown in Table 3.

[Comparative Examples 3 and 4]
In Comparative Examples 3 and 4, laminates and cup seals were produced and evaluated in the same manner as in Example 1, except that the composition and ratio of the adhesive and heat seal resin layer (C) were changed to those shown in Table 3.

As shown in Tables 2 and 3, for Comparative Examples 1 to 4, the adhesive layer (B) contains an acrylic copolymer (D), the heat seal resin layer (C) contains a polyethylene resin, Furthermore, in Examples 1 to 20 containing at least one of polypropylene resin and polybutene resin, a part of the heat-sealing resin layer (C) was heat-sealed to the lid material side when the lid material was peeled off from the container. In addition to exhibiting sufficient initial opening strength to prevent residue from remaining in the sealed portions or being pulled out in the form of strings (stringing), by pressing the lid and container after opening, it can be resealed with sufficient strength for practical use. It was shown that there was no bleeding of liquid components on the surface of the laminate.

Claims (5)

A laminate in which a base material (A), an adhesive layer (B), and a heat-sealing resin layer (C) are arranged in this order,
The adhesive layer (B) contains an acrylic copolymer (D),
The heat-sealing resin layer (C) contains a polyethylene resin, and further contains at least one of a polypropylene resin and a polybutene resin.
Resealable heat seal laminate. The resealable heat-sealable laminate according to claim 1, wherein the adhesive layer (B) further contains a curing agent (E). The resealable heat-sealable laminate according to claim 1, wherein the adhesive layer (B) further contains a tackifier (F). The resealable heat-sealable laminate according to claim 3, wherein the tackifier (F) includes a rosin-based tackifier (F1) or a terpene-based tackifier (F2). A resealable packaging container comprising the resealable heat seal laminate according to any one of claims 1 to 4 and a container body.