WO2022270321A1

WO2022270321A1 - Layered body, and wrapping paper or container using such layered body

Info

Publication number: WO2022270321A1
Application number: PCT/JP2022/023221
Authority: WO
Inventors: 浩菊池; 肇榎本
Original assignee: Ｄｉｃグラフィックス株式会社
Priority date: 2021-06-24
Filing date: 2022-06-09
Publication date: 2022-12-29
Also published as: JPWO2022270321A1; JP7317262B2

Abstract

The present invention is a layered body that at least includes: a paper base material; a first layer disposed on at least a section of the paper base material, and a second layer disposed on top of the first layer. One of the first layer and the second layer is a coating layer that contains a resin containing a styrene-acrylic copolymer comprising styrene, α-methylstyrene, and (meth)acrylate; and the other thereof is a coating layer that contains a heat-sealing agent. According to the present invention, it is possible to provide: a paper-based layered body having excellent water resistance and oil resistance and having a heat-sealing property; and also a wrapping body and a container using such layered body.

Description

Laminate and wrapping paper or container using the laminate

The present invention relates to a laminate and a wrapping paper or container using the laminate.

Paper packaging materials such as paper bags, paper boxes, and paper cups have traditionally been used for various purposes and purposes. In recent years, as the problem of marine plastic litter such as microplastics has been drawing attention, it has become one of the materials with functions such as "reusable" and "biodegradable" as an alternative to plastic materials. There is a growing movement to use "paper" made from "wood" which is a possible resource.

One of the paper containers that are currently in widespread use are paper cups used for beverages, ice cream, yogurt, etc. Although paper cups are made of paper, water resistance is imparted by using a polyethylene film as part of the raw material. Such paper cups are obtained by laminating a polyethylene film, a polypropylene film, or the like, which is obtained by extruding a polyethylene resin, a polypropylene resin, or the like melted with heat, onto a paper substrate. When the polyethylene film is molded into a paper cup, it acts as an adhesive by being melted by indirect heating such as a burner or hot air, and since the polyethylene film exists inside the paper cup, the paper base does not come into direct contact with the contents and is waterproof. properties, moisture resistance and strength.

However, since the laminated polyethylene film does not dissolve in the alkaline solution used in the paper recycling process, it must be physically removed, leading to a decrease in recycling efficiency. In addition, marine pollution due to the outflow of plastic waste into the ocean has become a global problem. One of the Sustainable Development Goals (SDGs) is to "By 2025 prevent and significantly reduce marine pollution of all kinds, especially pollution from land-based activities, including marine debris and eutrophication." It has become an important global theme, with agreements to strengthen efforts at summits (summer meetings of major countries). Therefore, there is a need for polyethylene film substitutes that are applicable to these uses and that do not reduce paper recycling efficiency.

On the other hand, water-based heat sealing agents are known to serve as adhesives when molding bags, boxes, paper cups, and the like. For example, in Patent Document 1, an ethylene-based resin aqueous dispersion obtained by mixing and dispersing an olefin-α,β-unsaturated carboxylic acid copolymer neutralized with ammonia or an amine and an olefin-based thermoplastic resin other than this at a specific ratio It is disclosed that the liquid can be applied as a heat sealing agent.

Further, in Patent Document 2, an aqueous dispersion containing a polyolefin resin composed of an unsaturated carboxylic acid unit, an ethylene-based hydrocarbon, and an acrylic acid ester or a methacrylic acid ester, a natural wax, and an aqueous medium in a specific ratio can be applied as a heat sealing agent.

JP-A-2000-7860 JP-A-2006-45313

However, there are still many problems in using paper packaging as an alternative to plastic packaging, which is heat-sealable, has excellent packaging design, and has excellent oil and water resistance. Although heat sealing agents for paper such as those disclosed in Patent Document 1 and Patent Document 2 have existed so far, these documents only disclose performance as a so-called heat sealing agent such as heat sealing strength and blocking resistance. There is no description of the water resistance and oil resistance desired as a substitute for polyethylene films. In other words, since there is no heat sealing agent with oil resistance and water resistance, improvement of oil resistance and water resistance is required when converting various plastic packaging materials such as billows to paper packaging materials.

That is, the present invention has at least a paper substrate, a first layer provided on at least a part of the paper substrate, and a second layer provided on the first layer, and the first layer Alternatively, one of the second layers is a coating layer containing a resin containing a styrene acrylic copolymer of styrene, α-methylstyrene and (meth)acrylate, and the other is a coating layer containing a heat sealing agent. It is a laminate.

The present invention also provides a package or container using the laminate.

Since the laminate of the present invention is a laminate of paper having excellent water resistance, oil resistance, and heat sealability, it is useful as a substitute for paper laminated with a plastic film, and is useful for various purposes. Moreover, it can contribute to paper recycling efficiency. In addition, the laminate of the present invention can easily obtain a laminate having excellent water resistance, oil resistance, and heat sealability to paper simply by coating, and furthermore, a mold is used. Since it is possible to prevent the heat sealing agent from adhering to the mold even when heat sealing is performed using the heat sealing agent, it is possible to improve the productivity and the quality of the product after heat sealing.

The laminate of the present invention has at least a paper substrate, a first layer provided on at least part of the paper substrate, and a second layer provided on the first layer. In the laminate of the present invention, one of the first layer and the second layer is a coat layer containing a resin containing a styrene-acrylic copolymer of styrene, α-methylstyrene, and (meth)acrylate (hereinafter referred to as " The other is a coat layer containing a heat-sealing agent (hereinafter referred to as a "heat-sealable coat layer"). That is, the laminate of the present invention has a layer in which an oil- and water-resistant coat layer and a heat-sealable coat layer are laminated, but the order of these layers is not particularly limited.

[Oil and water resistant coating layer]
The laminate of the present invention has an oil- and water-resistant coating layer as either the first layer or the second layer on the paper substrate. The oil- and water-resistant coating layer is formed from a coating composition (CS) containing an emulsion containing a styrene-acrylic copolymer (A) of styrene, α-methylstyrene, and (meth)acrylate, and an aqueous medium. is preferred.

<Coating composition (CS) containing styrene acrylic copolymer (A)>
(Emulsion containing styrene acrylic copolymer (A))
First, an emulsion containing a styrene-acrylic copolymer (A) of styrene, α-methylstyrene and (meth)acrylate will be described. In the present invention, (meth)acrylate is a generic term for acrylate and methacrylate, and (meth)acrylic acid is a generic term for acrylic acid and methacrylic acid.

In the present invention, α-methylstyrene in the styrene-acrylic copolymer (A) represents either o-methylstyrene, m-methylstyrene, p-methylstyrene or a mixture thereof.

In addition, the styrene-acrylic copolymer (A) includes styrene and styrene derivatives other than α-methylstyrene (p-dimethylsilylstyxystyrene, p-tert-butyldimethylsiloxystyrene, p-tert-butylstyrene), vinyl Naphthalene, vinylanthracene, 1,1-diphenylethylene, etc. may be partially used within the scope of the present invention.

The (meth)acrylate is not particularly limited, and examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, iso-propyl (meth)acrylate, allyl (meth)acrylate, n-(meth)acrylate, Butyl, iso-butyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, n-amyl (meth)acrylate, iso-amyl (meth)acrylate, (meth)acrylate n-hexyl acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-lauryl (meth)acrylate, n-tridecyl (meth)acrylate, n-stearyl (meth)acrylate , phenyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, tricyclodecanyl (meth)acrylate , dicyclopentadienyl (meth)acrylate, adamantyl (meth)acrylate, glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-methoxyethyl (meth)acrylate, (meth)acrylic acid 2-ethoxyethyl, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, trifluoroethyl methacrylate, tetrafluoropropyl methacrylate, pentafluoropropyl methacrylate, octafluoropentyl methacrylate, pentadeca methacrylate fluorooctyl, heptadecafluorodecyl methacrylate, N,N-dimethyl(meth)acrylamide, acryloylmorpholine, (meth)acrylonitrile, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, polyethylene glycol-polypropylene glycol (meth) Acrylate, polyethylene glycol-polybutylene glycol (meth)acrylate, polypropylene glycol-polybutylene glycol (meth)acrylate, methoxypolyethyleneglycol (meth)acrylate, ethoxypolyethyleneglycol (meth)acrylate, butoxypolyethyleneglycol (meth)acrylate, octoxy Polyethylene glycol (meth)acrylate, lauroxypolyethyleneglycol (meth)acrylate, stearoxypolyethyleneglycol (meth)acrylate General-purpose (meth)acrylic monomers containing polyalkylene oxide groups such as lylate, phenoxypolyethyleneglycol (meth)acrylate, methoxypolypropyleneglycol (meth)acrylate, octoxypolyethyleneglycol-polypropyleneglycol (meth)acrylate, etc. Acrylates can be used. Among them, a homopolymer having an acrylate is preferable because it exhibits a lower glass transition temperature, and it is preferable that the main component is an acrylate having an alkyl group having 1 to 20 carbon atoms, and an alkyl group having 1 to 12 carbon atoms. It is preferable that the main component is an acrylate having a Examples of such acrylates having an alkyl group having 1 to 12 carbon atoms include methyl acrylate, ethyl acrylate, iso-propyl acrylate, allyl acrylate, n-butyl acrylate, iso-butyl acrylate, ( meth)sec-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, iso-amyl acrylate, n-hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, (meth)acrylic acid n - includes lauryl and the like.

The (meth)acrylate used as a constituent component of the styrene-acrylic copolymer (A) of the present invention may be one type or two or more types, but two or more types of (meth)acrylates may be used. Among them, it is preferable to use two or more acrylates having an alkyl group having 1 to 12 carbon atoms as main components.

The emulsion containing the styrene-acrylic copolymer (A) preferably further contains a copolymer of (meth)acrylic acid and (meth)acrylate. A copolymer of (meth)acrylic acid and (meth)acrylate is a copolymer of (meth)acrylic acid and the (meth)acrylate (hereinafter sometimes referred to as acrylic copolymer (B)). . The (meth)acrylate is not particularly limited, but is preferably an acrylate having an alkyl group having 1 to 20 carbon atoms. The main component is preferably an acrylate having an alkyl group of 1 to 20 atoms, and preferably an acrylate having an alkyl group of 1 to 12 carbon atoms. Examples of such acrylates having an alkyl group having 1 to 12 carbon atoms include methyl acrylate, ethyl acrylate, iso-propyl acrylate, allyl acrylate, n-butyl acrylate, iso-butyl acrylate, ( meth)sec-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, iso-amyl acrylate, n-hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, (meth)acrylic acid n - includes lauryl and the like.

The emulsion containing the styrene-acrylic copolymer (A) preferably contains the styrene-acrylic copolymer (A) and the acrylic copolymer (B). The emulsion of the styrene-acrylic copolymer (A) polymerized by a known polymerization method using an aqueous medium, and the acrylic copolymer polymerized by a known polymerization method using an aqueous medium such as emulsion polymerization or transfer emulsification It may be an emulsion obtained by appropriately mixing the emulsion of (B), or an emulsion of a resin in which the styrene-acrylic copolymer (A) and the acrylic copolymer (B) form a core-shell structure. good. The "resin containing the styrene-acrylic copolymer (A)" may be a resin composed of the styrene-acrylic copolymer (A), or a resin containing the styrene-acrylic copolymer (A) and the acrylic copolymer (A). It may be a resin that forms a core-shell structure with coalescing (B).

The core-shell structure is formed by having a region in which the "styrene-acrylic copolymer (A)" is abundant and a region in which the "acrylic copolymer (B)" is abundant. be. In the core-shell structure, for example, "acrylic copolymer (B)" may be present in a region where "styrene-acrylic copolymer (A)" is abundant, or these copolymers may It may be polymerized.

The emulsion containing the styrene-acrylic copolymer (A) preferably contains a resin containing at least the styrene-acrylic copolymer (A) and has a minimum film-forming temperature in the range of -30°C to 30°C. The range of 10 to 25°C is more preferred, and the range of -5 to 20°C is even more preferred. In the present invention, the minimum film-forming temperature is the minimum temperature required to form a continuous film when the synthetic rubber latex evaporates and dries, and is obtained by the temperature gradient plate method.

The glass transition temperature (hereinafter sometimes referred to as Tg) of the emulsion containing the styrene-acrylic copolymer (A) is preferably in the range of -40°C to 30°C, especially in the range of -35°C to 25°C. It is preferably in the range of -30 to 23°C. In the present invention, the glass transition temperature is obtained by measurement with a differential scanning calorimeter.

The acid value of the emulsion is preferably in the range of 30-80 mgKOH/g, more preferably in the range of 40-75 mgKOH/g, more preferably in the range of 50-70 mgKOH/g. In the present invention, the acid value is obtained by a measuring method based on JIS test method K 0070-1992.

The coating composition (CS) containing the emulsion of the styrene-acrylic copolymer (A) has fine film-forming properties without defects such as pinholes, and is therefore excellent in water resistance and oil resistance. Therefore, the water resistance and oil resistance of the laminate can be improved. In addition, since the coating composition (CS) also has adhesiveness, it is excellent in adhesiveness to the heat-sealable coat layer and/or the paper substrate, and does not impair the function of the heat-sealable coat layer. Excellent compatibility when used in combination with a heat-sealable coating layer.

In addition, since the composition of the present invention contains the styrene-acrylic copolymer (A), the heat resistance is improved. Therefore, it is applicable even when the contents are at high temperature such as heated food.

(Method for producing emulsion containing styrene-acrylic copolymer (A))
In the present invention, the emulsion can be obtained by polymerization using a known aqueous medium, such as known emulsion polymerization or transfer emulsification, without any particular limitation. Although there are various expressions such as emulsion, dispersion, suspension, etc. for the form in which a polymer is dispersed in an aqueous medium, the term "emulsion" is unified in the present invention.

For example, a monomer mixture is supplied in an aqueous medium, and the monomer mixture is polymerized in the presence of an initiator to polymerize an emulsion.

In the case of an emulsion obtained by appropriately mixing the emulsion of the styrene-acrylic copolymer (A) and the emulsion of the acrylic copolymer (B), it is obtained by mixing emulsions obtained by polymerizing the respective monomer mixtures.

In the case of an emulsion forming a core-shell structure, a step (1) of supplying a monomer mixture forming a core polymer and polymerizing the monomer mixture in the presence of an initiator to form a core polymer; to the core polymer of step (1) and polymerizing the monomer mixture in the presence of an initiator to form a shell on the core polymer (step (2)). In addition, step (i) of supplying a monomer mixture that forms a shell polymer and polymerizing the monomer mixture in the presence of an initiator to form a shell polymer; and polymerizing this monomer mixture in the presence of an initiator to form a shell on the core polymer (ii).

The initiator is not particularly limited, and peroxides, persulfates, azo compounds, redox compounds, or mixtures thereof used in the emulsion polymerization method may be used. Peroxides include, for example, hydrogen peroxide, ammonium peroxide, sodium or potassium peroxide, t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, and benzene peroxide. Persulfates include, for example, ammonium persulfate, sodium persulfate, or potassium persulfate. Examples of azo compounds include 2,2-azobisisobutyronitrile and 4,4'-(4-cyanovaleric acid). The redox system also consists of an oxidizing agent and a reducing agent, the oxidizing agent being, for example, one of the peroxides, persulfates or azo compounds listed above, or sodium chloride or potassium chloride, or sodium bromide or Potassium bromide may be mentioned. Examples of reducing agents include ascorbic acid, glucose, or ammonium, sodium or potassium hydrogen sulfate, sodium or potassium hydrogen sulfite, sodium thiosulfate or potassium thiosulfate, or sodium or potassium sulfide, or iron (II ) ammonium sulfate. Among them, persulfates, more preferably ammonium persulfate, are preferred.

The polymerization of the monomer mixture can be carried out in the presence of additives such as surfactants, chain transfer agents and chelating agents, for example in the presence of surfactants and chain transfer agents. These additives may be added in advance to the aqueous medium used in step (1), or may be mixed with the monomer mixture supplied in step (1) or step (2).

The surfactant is not particularly limited, but includes, for example, disodium dodecyldiphenyl oxide, disulfonate, and the like. Although the chain transfer agent is not particularly limited, examples thereof include α-methylstyrene dimer, thioglycolic acid, sodium hydrogen phosphite, 2-mercaptoethanol, N-dodecylmercaptan, and t-dodecylmercaptan. The chelating agent is not particularly limited, but includes, for example, ethylenediaminetetraacetic acid.

When forming a core-shell structure, in order to increase the stability in an aqueous medium, it is preferable that the acrylic copolymer (B) having an acidic group serves as the shell. There is no problem even if the emulsion has a structure in which (B) does not form a shell and part of the styrene-acrylic copolymer (A) forms a shell.

Also, when neutralization is required, bases such as ammonia, triethylamine, aminomethylpropanol, monoethanolamine, diethylaminoethanol, sodium hydroxide, and potassium hydroxide can be used as neutralizing agents.

(Other resins)
The coating composition (CS) of the present invention may contain resins other than the styrene-acrylic copolymer (A) and the acrylic copolymer (B). Materials for other resins are not particularly limited, but in order not to impair the properties of the coating composition (CS) of the present invention, such as oil resistance and heat resistance, it is preferably a styrene-acrylic copolymer. More preferably, it is the same material as the resin containing the styrene-acrylic copolymer (A). In addition, the content of other resins can be appropriately adjusted within a range that does not impair the effects of the present invention, but the weight ratio of the resin containing the styrene-acrylic copolymer (A) to the other resins (the styrene-acrylic copolymer (A)/other resin) is preferably 100/0 to 50/50, preferably 100/0 to 60/40.

(Aqueous solvent)
The coating composition (CS) contains water. As water, pure water such as ion-exchanged water, ultrafiltrated water, reverse osmosis water, distilled water, or ultrapure water can be used. As the water, it is preferable to use water that has been sterilized by ultraviolet irradiation, addition of hydrogen peroxide, or the like, because it can prevent the generation of mold or bacteria when the composition is stored for a long period of time. Among them, it is most preferable to use water.
A water-soluble organic solvent such as an alcohol that dissolves in water may be mixed and used. Examples of alcohols include methanol, ethanol, isopropyl alcohol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, butyl alcohol and pentyl alcohol. These alcohols can be used alone or in combination of two or more.

(Other additives)
The coating composition (CS) may also contain silica, alumina, polyethylene wax, antifoaming agents, leveling agents, tackifiers, preservatives, antibacterial agents, antirust agents, and the like.

The coating composition (CS) may contain wax. Waxes include waxes such as fatty acid amide wax, carnauba wax, polyolefin wax, paraffin wax, Fischer-Tropsch wax, beeswax, microcrystalline wax, polyethylene oxide-wax, amide wax, and the like. These may be used alone or in combination.

Among them, it is preferable to use fatty acid amide wax, carnauba wax, Fischer-Tropsch wax, polyolefin wax, and paraffin wax, and it is particularly preferable to use carnauba wax, polyolefin wax, and paraffin wax.

Specific examples of fatty acid amide waxes include pelargonic acid amide, capric acid amide, undecylic acid amide, lauric acid amide, tridecylic acid amide, myristic acid amide, pentadecylic acid amide, palmitic acid amide, heptadecylic acid amide, and stearic acid amide. , nonadecanic acid amide, arachidic acid amide, behenic acid amide, lignoceric acid amide, oleic acid amide, cetreic acid amide, linoleic acid amide, linoleic acid amide, mixtures thereof and animal and vegetable oil fatty acid amides.

Specific examples of the carnauba wax include MICROK LEAR 418 (manufactured by Micro Powders, Inc.) and refined carnauba wax No. 1 powder (Nippon Wax Co., Ltd.).

Specific examples of the olefin wax include polyethylene wax and polypropylene wax, such as MPP-635VF (Micro Powders, Inc.) and MP-620VF XF (Micro Powders, Inc.).

Specific examples of the paraffin wax include MP-28C, MP-22XF and MP-28C (Micro Powders, Inc.).

The blending amount of the wax is preferably 1.5 to 20% by mass with respect to the total amount of 100% by mass of the solid content in the coating composition (CS). If the total amount of wax is 3% by mass or more with respect to the total solid content of 100% in the coating composition (CS), the blocking resistance tends to be maintained, and the total amount of wax is the total amount of 100% solid content of the coating composition (CS). If it is 15% by mass or less, the heat-sealing property tends to be maintained.

Also, the melting point of the wax is preferably in the range of 80° C. to 130° C. from the viewpoint of oil resistance and heat resistance. The wax may be directly added to the resin emulsion containing the styrene-acrylic copolymer (A) and mixed and dispersed, or a wax dispersion may be prepared and then mixed with the emulsion. As a dispersion method, a known method such as a dispersion device using media such as a paint shaker, a ball mill, an attritor, a basket mill, a sand mill, a sand grinder, a Dyno mill, a Dispermat, an SC mill, a spike mill, and an agitator mill is used. Dispersion can be carried out by an ultrasonic homogenizer, a high-pressure homogenizer, a nanomizer, a dissolver, a disper, a high-speed impeller disperser, or the like, which does not use media.

When powdered wax is used, it is preferable to perform kneading using a media or mix after preparing a dispersion of wax in order to uniformly disperse the wax. The kneading method can be performed by a known method.

When using multiple types of waxes together, the multiple types of waxes may be added at the same time, or may be added in multiple steps.

In addition, the coating composition (CS) preferably uses a polymer-based antifoaming agent, a silicon-based antifoaming agent, or a fluorine-based antifoaming agent in order to prevent foaming of the composition during coating using various coaters. be done. As these antifoaming agents, both emulsifying and dispersing types and solubilizing types can be used. Among them, polymer antifoaming agents are preferred.

The amount of the antifoaming agent added is preferably 0.005% to 0.1% by weight of the total amount of the coating composition (CS).

[Heat-sealable coating layer]
The laminate of the present invention has a heat-sealable coating layer as either the first layer or the second layer on the paper substrate. A known heat-seal coating agent can be used for the heat-sealable coating layer. Composition examples of the heat sealing agent are described below.

<Heat sealing agent (HS)>
In order to improve water resistance, heat sealing agents (HS) are vinyl chloride vinyl acetate copolymer resins, (meth)acrylate resins, olefin-α,β unsaturated carboxylic acid copolymer resins, and polyolefin resins. Alternatively, it preferably contains at least one selected from polyester resins, and at least one selected from vinyl chloride vinyl acetate copolymer resins, (meth)acrylate resins, and olefin-α,β unsaturated carboxylic acid copolymer resins. It is more preferable to include

The vinyl chloride-vinyl acetate copolymer resin is not particularly limited as long as it is a copolymer of vinyl chloride and vinyl acetate. From the viewpoint of improving the heat-sealing property, it is preferably a vinyl chloride-vinyl acetate copolymer containing an acid group, and more preferably an acid-modified vinyl chloride-vinyl acetate copolymer-based resin. As the acid group, those using maleic acid or fumaric acid are preferred.

The (meth)acrylate resin is not particularly limited as long as it is a homopolymer or copolymer of (meth)acrylate. and copolymers. Further, when an aqueous solvent is used, it is preferably a copolymer having an acid value for the purpose of imparting water dispersibility and water solubility.

The (meth)acrylate used as a constituent component of the (meth)acrylate homopolymer or copolymer is not particularly limited, and is similar to the (meth)acrylate used in the styrene-acrylic copolymer (A) described above. is used.

Examples of (meth)acrylates and vinyl monomers copolymerizable with (meth)acrylates include aromatic (meth)acrylates such as benzyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, 2- hydroxyl group-containing monomers such as hydroxypropyl (meth)acrylate; alkylpolyalkylene glycol mono(meth)acrylates such as methoxypolyethylene glycol mono(meth)acrylate and methoxypolypropylene glycol mono(meth)acrylate; perfluoroalkylethyl (meth)acrylate, etc. fluorine-based (meth)acrylate; styrene, styrene derivatives (p-dimethylsilylstyrene, (p-vinylphenyl) methylsulfide, p-hexynylstyrene, p-methoxystyrene, p-tert-butyldimethylsiloxystyrene, o- methylstyrene, p-methylstyrene, p-tert-butylstyrene, α-methylstyrene, etc.), aromatic vinyl compounds such as vinylnaphthalene, vinylanthracene, 1,1-diphenylethylene; glycidyl (meth)acrylate, epoxy (meth ) acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylene glycol tetra(meth)acrylate, 2-hydroxy-1,3-diacryloxypropane, 2 , 2-bis[4-(acryloxymethoxy)phenyl]propane, 2,2-bis[4-(acryloxyethoxy)phenyl]propane, dicyclopentenyl (meth)acrylate tricyclodecanyl (meth)acrylate, tris (Acryloxyethyl)isocyanurate, (meth)acrylate compounds such as urethane (meth)acrylate; having an alkylamino group such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, etc. (Meth)acrylates; vinylpyridine compounds such as 2-vinylpyridine, 4-vinylpyridine and naphthylvinylpyridine; 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3- conjugated dienes such as butadiene, 1,3-pentadiene, 1,3-hexadiene and 1,3-cyclohexadiene; These monomers can be used singly or in combination of two or more.

In addition, for the purpose of introducing one or more acidic groups selected from the group consisting of carboxyl groups and carboxylate groups in which the carboxyl groups are neutralized with a basic compound, (meth)acrylic acid, crotonic acid, itaconic acid, , Maleic acid, fumaric acid, β-(meth)acryloyloxyethyl hydrogen succinate, β-(meth)acryloyloxyethyl hydrogen phthalate, etc.) It is possible to obtain a copolymer having

When introducing an acidic group, it is preferable to appropriately adjust the monomer amount so that the acid value is within the desired range.

The (meth)acrylate homopolymer or copolymer can be produced, for example, by polymerizing one or more monomers in the presence of a polymerization initiator in a temperature range of 50°C to 180°C. , 80° C. to 150° C. is more preferable. Polymerization methods include, for example, bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Moreover, the polymerization mode includes, for example, random copolymers, block copolymers, graft copolymers, and the like. The copolymer may also be of the core-shell type.

The olefin-α,β-unsaturated carboxylic acid copolymer resin includes an olefin, an α,β-unsaturated carboxylic acid, a metal salt of an α,β-unsaturated carboxylic acid, and an α,β-unsaturated carboxylic acid. Examples thereof include copolymers with at least one monomer selected from the group consisting of esters. Specifically, it is a copolymer of an α,β-unsaturated carboxylic acid, a metal salt of an α,β-unsaturated carboxylic acid or an α,β-unsaturated carboxylic acid ester and an olefin, and an olefin-α,β Unsaturated carboxylic acid copolymer, ethylene-acrylic acid ester copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-acrylic acid-maleic anhydride copolymer, ethylene-acrylic acid Ester-maleic anhydride copolymers, ethylene-methacrylic acid-maleic anhydride copolymers, ethylene-methacrylic acid ester-maleic anhydride copolymers, metal salts thereof and the like can be mentioned. These copolymers may be used alone or as a mixture of two or more.
Among them, an olefin-α,β unsaturated carboxylic acid copolymer is preferred. Olefin-α,β-unsaturated carboxylic acid copolymers include random copolymers or block copolymers of ethylene- and α,β-unsaturated carboxylic acids.

Examples of the olefin include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 4-methyl-1-pentene, butadiene, dicyclopentadiene, 5-ethylidene-2- and norbornene. Among them, ethylene is preferred.

Examples of the α,β-unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid. Among these, acrylic acid and methacrylic acid are preferably used. These α,β-unsaturated carboxylic acids may be used alone or in combination of two or more.

As the α,β-unsaturated carboxylic acid ester, known alkyl esters, hydroxyalkyl esters, alkoxyalkyl esters, etc. of acrylic acid or methacrylic acid can be used without particular limitation. For example, specifically, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, n-octyl acrylate, acrylate- acrylic esters such as 2-hydroxyethyl and 2-methoxyethyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, Methacrylic acid esters such as 2-ethylhexyl methacrylate, n-lauryl methacrylate, 2-hydroxyethyl methacrylate, and 2-ethoxyethyl methacrylate can be exemplified. These can be used singly or in combination of two or more.

The olefin-α,β unsaturated carboxylic acid copolymer can be produced by a known method such as radical copolymerization at high temperature and high pressure.

The content of α,β-unsaturated carboxylic acid in the olefin-α,β-unsaturated carboxylic acid copolymer is desirably 8 to 24% by weight, preferably 18 to 23% by weight. When the content of the α,β-unsaturated carboxylic acid is less than 8% by weight, the dispersibility in the aqueous dispersion medium is inferior due to the non-polar nature derived from the ethylene unit, and the olefin-α,β-unsaturation is excellent. It may become difficult to obtain a carboxylic acid copolymer resin aqueous dispersion. On the other hand, if the content of the α,β-unsaturated carboxylic acid exceeds 24% by weight, the anti-blocking property of the resulting film may deteriorate.

The olefin-α,β unsaturated carboxylic acid copolymer used in the heat sealing agent is preferably used as an aqueous dispersion dispersed in an aqueous solvent. The method for dispersing in the aqueous solvent is not particularly limited, and any known method may be used. Examples include a method of emulsifying with a surfactant and dispersing it in an aqueous solvent, and a method of neutralizing an olefin-α,β unsaturated carboxylic acid copolymer with a basic compound and then dispersing it in an aqueous solvent.

As the surfactant used for the emulsification, various known anionic, cationic, nonionic surfactants, or various water-soluble polymers can be appropriately used in combination.

Examples of basic compounds used for neutralization include organic amines such as ammonia, methylamine, ethylamine, diethylamine, dimethylethanolamine, diethanolamine and triethanolamine, sodium hydroxide, potassium hydroxide and lithium hydroxide. and other alkali metal hydroxides. These basic compounds may be used alone or in combination of two or more.

The degree of neutralization by the basic compound should be such that the olefin-α,β unsaturated carboxylic acid copolymer is stably present in the aqueous solvent. For example, it may be 30 to 100 mol %, more preferably 40 to 90 mol %, of the carboxyl groups in the copolymer.

Examples of the dispersing method include known methods such as a dispersing device using media such as a paint shaker, ball mill, attritor, basket mill, sand mill, sand grinder, dyno mill, dispermat, SC mill, spike mill, and agitator mill. Dispersion can be carried out using an ultrasonic homogenizer, a high-pressure homogenizer, a nanomizer, a dissolver, a disper, a high-speed impeller disperser, or the like, which does not use media.

The solid content of the aqueous dispersion of the olefin-α,β unsaturated carboxylic acid copolymer used in the present invention is not particularly limited. It may be appropriately determined depending on the drying conditions, the film thickness of the film, and the like. In general, the solid content concentration is often applied in the range of 10 to 40% by mass.

(solvent)
The heat sealing agent (HS) is preferably used by dissolving the above-described resin in various organic solvents or aqueous solvents in order to improve coating performance. For example, when vinyl chloride-vinyl acetate copolymer system resin, (meth)acrylate system resin, polyolefin system resin or polyester system resin is used, it is preferable to use an organic solvent.

The organic solvent is not particularly limited, and examples include aromatic hydrocarbons such as toluene, xylene, Solvesso #100 and Solvesso #150, aliphatic hydrocarbons such as hexane, heptane, octane, and decane, methyl acetate, and acetic acid. Various ester-based organic solvents such as ethyl, isopropyl acetate, butyl acetate, amyl acetate, ethyl formate, and butyl propionate can be used. In addition, alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, methyl ethyl ketone and cyclohaxanone, ethylene glycol (mono, di)methyl ether, ethylene glycol (mono, di)ethyl ether, ethylene glycol monopropyl ether, Ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol (mono, di)methyl ether, diethylene glycol (mono, di)ethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol (mono, di)methyl ether, propylene glycol ( Glycol ethers such as mono, di)methyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and dipropylene glycol (mono, di) methyl ether, organic solvents with good solubility such as N,N-dimethylformamide, Examples include various organic solvents such as N,N-diethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and other amide solvents. Among these, it is preferable to use toluene, methyl ethyl ketone, ethyl acetate, or a mixture thereof, which usually has a high drying speed.

When using a (meth)acrylate resin or a polyolefin resin, it is preferable to use an aqueous solvent. As the aqueous solvent, the same aqueous solvent as used in the coating composition (CS) can be used. Among them, it is preferable to use water.

(wax)
The heat sealing agent (HS) preferably contains wax. Blocking resistance can be maintained by containing wax. Examples of the wax include waxes such as fatty acid amide wax, carnauba wax, polyolefin wax, paraffin wax, Fischer-Tropsch wax, beeswax, microcrystalline wax, polyethylene oxide wax, amide wax, coconut oil fatty acid and soybean oil fatty acid. be able to. These may be used alone or in combination.

Among them, it is preferable to use fatty acid amide wax, carnauba wax, Fischer-Tropsch wax, polyolefin wax, and paraffin wax, and it is particularly preferable to use fatty acid amide wax and carnauba wax.

Specific examples of fatty acid amide waxes include pelargonic acid amide, capric acid amide, undecylic acid amide, lauric acid amide, tridecylic acid amide, myristic acid amide, pentadecylic acid amide, palmitic acid amide, heptadecylic acid amide, and stearic acid amide. , nonadecanic acid amide, arachidic acid amide, behenic acid amide, lignoceric acid amide, oleic acid amide, cetreic acid amide, linoleic acid amide, linoleic acid amide, mixtures thereof and animal and vegetable oil fatty acid amides.
Specific examples of the carnauba wax include MICROKLEAR 418 (manufactured by Micro Powders, Inc.) and purified carnauba wax No. 1 powder (Nippon Wax Co., Ltd.).

As for the blending amount of the wax, the total amount of wax is preferably 1.5 to 20% by mass with respect to the total solid content of 100% by mass of the heat sealing agent (HS). If the total amount of wax is 3% by mass or more with respect to the solid content of 100% of the heat sealing agent (HS), the blocking resistance tends to be maintained, and the total amount of wax is 100% of the solid content of the heat sealing agent (HS). If it is 15% by mass or less with respect to the total amount, there is a tendency that the heat-sealing property can be maintained.

Of the waxes, the combined use of the fatty acid amide wax and the carnauba wax is more preferable because the blocking resistance is further improved. When used in combination, the ratio is not particularly limited, but the ratio of fatty acid amide wax to the carnaval wax is preferably in the range of 1:1 to 1:10, more preferably 1:1 to 1:5.

Further, among the above waxes, it is more preferable to use a polyolefin wax and a paraffin wax in combination, since the anti-blocking property is further improved. When used in combination, the ratio is not particularly limited, but the polyolefin wax:paraffin wax ratio is preferably in the range of 1:1 to 10:1, more preferably in the range of 1:1 to 5:1.

When using a water-based solvent, it is preferable to further use wax, and it is particularly preferable to use it in combination with the olefin-α,β unsaturated carboxylic acid copolymer or (meth)acrylic resin. In this case, the wax may be added directly to the aqueous dispersion of the olefin-α,β unsaturated carboxylic acid copolymer or (meth)acrylic resin and mixed and dispersed, or the olefin-α,β unsaturated carboxylic acid copolymer It may be added and mixed and dispersed at the same time as the polymer or (meth)acrylic resin is dispersed in the aqueous solvent. As a dispersing method, the method used for dispersing the above-described olefin-α,β unsaturated carboxylic acid copolymer in an aqueous solvent can be appropriately used.

When using multiple types of waxes together, the multiple types of waxes may be added at the same time, or may be added in multiple steps. For example, after the first wax is added when dispersing the olefin-α,β unsaturated carboxylic acid copolymer or (meth)acrylic resin in an aqueous solvent, the second wax is added to the obtained first wax. and the olefin-α,β unsaturated carboxylic acid copolymer or (meth)acrylic resin are further added to an aqueous dispersion to obtain a heat sealing agent (HS).

The heat sealing agent (HS) contains silica, alumina, antifoaming agent, viscosity modifier, leveling agent, tackifier, antiseptic agent, antibacterial agent, antibacterial agent, antiseptic agent, silica, alumina, antifoaming agent, viscosity modifier, antiseptic agent, antibacterial agent, antiseptic agent, antiseptic agent, antiseptic agent Additives such as rust agents, antioxidants and silicone oils may be added.

In addition, for the heat sealing agent (HS), polymer antifoaming agents, silicon antifoaming agents, and fluorine antifoaming agents are preferably used in order to prevent foaming during coating using various coaters. As these antifoaming agents, both emulsifying and dispersing types and solubilizing types can be used. Among them, polymer antifoaming agents are preferred. The amount of the antifoaming agent to be added is preferably 0.005% by weight to 0.1% by weight based on the total amount of the water-based heat sealing agent.

The heat sealing agent (HS) can be used as a heat sealing agent when manufacturing paper packaging materials such as bags and boxes, and paper containers. Lamination with the polymer coat layer can further improve the water resistance of the laminate. By laminating the heat-sealed portion, various packaging materials such as bags, boxes, containers, etc. can be produced according to the application, and the workability is excellent.

[Laminate]
The laminate of the present invention has at least a first layer on a paper substrate and a second layer provided on the first layer.

As the paper base material, natural fibers for papermaking such as wood pulp are used and manufactured by a known papermaking machine, but the papermaking conditions are not particularly specified. Examples of natural fibers for papermaking include wood pulp such as softwood pulp and hardwood pulp, non-wood pulp such as Manila hemp pulp, sisal pulp and flax pulp, and pulp obtained by chemically modifying these pulps. The types of pulp that can be used include chemical pulp, ground pulp, chemi-grand pulp, thermomechanical pulp, and the like prepared by sulfate cooking, acid/neutral/alkaline sulfite cooking, soda salt cooking, and the like. Moreover, various types of commercially available fine paper, coated paper, lined paper, impregnated paper, cardboard, paperboard, etc. can also be used.

As for the paper substrate, the type, thickness, etc. of the paper can be successively selected according to the purpose. For example, a burger wrap corresponds to a basis weight of about 20 g/m ² , a paper cup corresponds to a basis weight of 200 to 300 g/m ² , and a paper plate, paper spoon, paper muddler, etc. corresponds to a basis weight of 50 to 500 g/m 2 . Food base papers such as gram/m ² cup base paper are preferred. From the viewpoint of recycling efficiency and cost reduction, it is preferable that these papers are not laminated with a polyethylene film, aluminum, or the like. The paper substrate may have a printed layer. The printed layer may be provided on the surface of the paper substrate on which the first layer is provided, or on the surface opposite to the surface on which the first layer is provided.
The printing layer (E) is a layer for forming a desired pattern with a liquid printing ink in order to impart cosmetic properties, various information regarding contents, and functionality to the printed material. The printing layer is printed with gravure printing ink or flexographic printing ink (hereinafter referred to as liquid printing ink) containing a binder resin and a colorant.

The printed layer (E) used in the present invention may be a single layer or may have multiple printed layers. When there are a plurality of printing layers, the liquid printing ink used for each printing layer may be the same, may have the same composition with a different colorant, or may have a different composition. Also good.

(liquid printing ink)
Liquid printing inks used in the present invention are used as gravure printing inks and flexographic printing inks, and are broadly classified into organic solvent-based liquid printing inks whose main solvent is an organic solvent and water-based liquid printing inks whose main solvent is water. However, either one may be used in the present invention. In addition, there are so-called surface printing ink and reverse printing ink which is premised on lamination, but either one may be used in the present invention.
Here, the mainstream organic solvent type liquid printing ink will be explained.

The binder resin (A) used in the liquid printing ink used in the present invention includes cellulose resins such as nitrocellulose, cellulose acetate propionate (CAP) and cellulose acetate butyronate (CAB). Vinyl chloride resins such as polyamide resins, urethane resins, acrylic resins, vinyl chloride-vinyl acetate copolymer resins, chlorinated polypropylene resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, polyvinyl chloride resins, etc. Polyester resins, alkyd resins, rosin-based resins, rosin-modified maleic acid resins, ketone resins, cyclized rubbers, chlorinated rubbers, butyral, petroleum resins and the like can be mentioned.

Moreover, you may use a hardening|curing agent together with binder resin (A). As the curing agent, general-purpose curing agents for organic solvent-based gravure printing inks may be used, but isocyanate-based curing agents are most frequently used.
The amount of the isocyanate compound added is preferably in the range of 0.3% by mass to 10.0% by mass based on the solid content of the liquid printing ink from the viewpoint of curing efficiency, and if it is 1.0% by mass to 7.0% by mass. more preferred.
The binder resin (A) is preferably used in the range of 0.15 to 50% by weight, most preferably in the range of 1 to 40% by weight, based on the liquid printing ink.

(solvent)
The solvent used for the liquid printing ink used in the present invention is not particularly limited, but examples include water, toluene, xylene, aromatic hydrocarbon organic solvents such as Solvesso #100 and Solvesso #150, hexane, methylcyclohexane, Aliphatic hydrocarbon organic solvents such as heptane, octane, and decane, and various ester organic solvents such as methyl acetate, ethyl acetate, isopropyl acetate, normal propyl acetate, butyl acetate, amyl acetate, ethyl formate, and butyl propionate. be done. Water-miscible organic solvents include alcohols such as methanol, ethanol, propanol, butanol and isopropyl alcohol, ketones such as acetone, methyl ethyl ketone and cyclohaxanone, ethylene glycol (mono, di) methyl ether, and ethylene glycol (mono, di) ethyl. Ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol (mono, di) methyl ether, diethylene glycol (mono, di) ethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol (mono, Di)methyl ether, propylene glycol (mono, di)methyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol (mono, di)methyl ether, and other glycol ether organic solvents can be used. These may be used alone or in combination of two or more.

(coloring agent)
The liquid printing ink used in the present invention contains a coloring agent, and can be used as a liquid printing ink containing a coloring agent for use in design printing and the like for the purpose of imparting cosmetic properties and the like. Examples of the coloring agent include inorganic pigments, organic pigments, and dyes used in general inks, paints, recording agents, and the like, with pigments being preferred. Examples of organic pigments include soluble azo, insoluble azo, azo, phthalocyanine, halogenated phthalocyanine, anthraquinone, anthanthrone, dianthraquinonyl, anthrapyrimidine, perylene, perinone, quinacridone, Pigments such as thioindigo, dioxazine, isoindolinone, quinophthalone, azomethineazo, flavanthrone, diketopyrrolopyrrole, isoindoline, indanthrone, and carbon black pigments can be used. Also, for example, Carmine 6B, Lake Red C, Permanent Red 2B, Disazo Yellow, Pyrazolone Orange, Carmine FB, Chromophtal Yellow, Chromophtal Red, Phthalocyanine Blue, Phthalocyanine Green, Dioxazine Violet, Quinacridone Magenta, Quinacridone Red, Indance Ron blue, pyrimidine yellow, thioindigo bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, daylight fluorescent pigments, and the like. Both non-acid-treated pigments and acid-treated pigments can be used.
Examples of inorganic pigments include white inorganic pigments such as titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, litbon, antimony white, and gypsum. Among inorganic pigments, the use of titanium oxide is particularly preferred. Titanium oxide exhibits a white color and is preferable from the viewpoint of coloring power, hiding power, chemical resistance, and weather resistance. From the viewpoint of printing performance, the titanium oxide is preferably treated with silica and/or alumina.
Examples of non-white inorganic pigments include aluminum particles, mica (mica), bronze powder, chrome vermilion, yellow lead, cadmium yellow, cadmium red, ultramarine blue, Prussian blue, red iron oxide, yellow iron oxide, iron black, and zircon. Although the aluminum is in the form of powder or paste, it is preferable to use it in the form of paste from the standpoint of handling and safety, and whether to use leafing or non-leafing is appropriately selected from the viewpoint of brightness and density.

The amount of the pigment is sufficient to ensure the concentration and coloring strength of the liquid printing ink, that is, 1 to 60% by mass relative to the total mass of the liquid printing ink, and the solid content weight ratio in the liquid printing ink is 10 to 90 mass. %. Moreover, these pigments can be used individually or in combination of 2 or more types.

Organic solvent-based liquid printing inks may also contain waxes, chelate cross-linking agents, extender pigments, leveling agents, antifoaming agents, plasticizers, infrared absorbers, ultraviolet absorbers, fragrances, flame retardants, etc. can also

(biomass liquid printing ink)
In the liquid printing ink used in the present invention, it is preferable to use a liquid printing ink using a plant-derived raw material in consideration of the construction (sustainability) of a recycling-oriented society that should be sustainably developed.
Examples of plant-derived raw materials include cellulose-based resins such as cellulose acetate propionate resin and nitrocellulose, and polyamides using dimer acid or polymerized fatty acid derived from natural oils such as soybean oil, palm oil, and rice bran oil. Resins and polycarboxylic acids such as succinic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, dimer acid, glutaric acid, and malic acid, and polyols such as ethylene glycol, 1,2-propanediol, 1,3 - Propanediol, 1,4-butanediol, neopentyl glycol, pentylene glycol, 1,10-dodecanediol, dimer diol, isosorbide, etc. Plant-derived polyisocyanates such as 1,5-pentamethylene diisocyanate, dimer diisocyanate, etc. Examples include biomass polyurethane synthesized from raw materials and rosin resin.

Commercial products can also be used as biomass liquid printing inks. As commercially available products, inks listed by the Japan Organic Resources Association can be used.

(UV cut ink)
In the liquid printing ink used in the present invention, it is also preferable to use a UV cut ink having an ultraviolet shielding effect. The UV cut ink is not particularly limited as long as it contains zinc oxide or the like and has a high ultraviolet shielding effect, and commercially available UV cut inks can be used.

The first layer is a layer provided between the paper substrate and the second layer. The first layer is composed of either the oil- and water-resistant coating layer or the heat-sealable coating layer described above. The coating amount of the first layer is 0.5 to 10.0 g/m ² , more preferably 1.0 to 5.0 g/m ² .

The second layer is a layer provided on top of the first layer. The second layer is formed of a layer different from the first layer, out of the oil- and water-resistant coating layer or the heat-sealable coating layer described above. That is, when the first layer is formed of the oil- and water-resistant coating layer, the second layer is formed of the heat-sealable coating layer, and when the first layer is formed of the heat-sealable coating layer, the second layer is formed of the heat-sealable coating layer. The second layer is formed by an oil- and water-resistant coating layer.

The coating amount of the second layer is preferably 0.5 to 8.0 g/m ² , more preferably 1.0 to 5.0 g/m ² . When the first layer is an oil- and water-resistant coating layer, the sealing function of the first layer can reduce the coating amount of the heat sealing agent for the second layer.

The laminate may further have a third layer on the side of the paper substrate on which the first layer and the second layer are not provided. For the third layer, it is preferable to appropriately select and use various coating agents depending on the performance desired to be imparted to the laminate. For example, the styrene-acrylic copolymer coating layer described above may be provided as the third layer. Moreover, when it is desired to further improve water resistance, it is more preferable to use a water-resistant coating layer containing at least a styrene-acrylic copolymer and wax.

[Water resistant coating layer]
The water-resistant coating layer provided as the third layer is preferably formed from a water-resistant coating composition containing at least an aqueous solvent, a styrene-acrylic copolymer, and wax. The thickness of the waterproof coating layer depends on the application, but is preferably in the range of 1 to 10 g/m ² , more preferably in the range of 1 to 5 g/m ² .

(Aqueous solvent)
As the water-based solvent, the same water-based solvent as that used for the heat sealing agent (HS) can be used.

(Styrene-acrylic copolymer)
Styrene-acrylic copolymers are preferably copolymers of styrenes and (meth)acrylates forming a core-shell structure, and copolymers of styrenes and (meth)acrylates, and styrenes and (meth) ) More preferably, a copolymer of acrylate and (meth)acrylic acid forms a core-shell structure.

The styrenes and (meth)acrylates used as constituents of the styrene-acrylic copolymer may be the same as those used in the styrene-acrylic copolymer (A) of the styrene-acrylic copolymer coating layer described above. can.

As a constituent component of the styrene-acrylic copolymer, other known polymerizable compounds other than styrenes, (meth)acrylates, and (meth)acrylic acid may be contained.

The styrene-acrylic copolymer (A) may contain a wax, which will be described later. Water resistance can be further improved by containing wax in the styrene-acrylic copolymer (A). Wax may be present in the core portion or in the shell portion. It may exist on the surface of the styrene-acrylic copolymer.

In the styrene-acrylic copolymer (A), the ratio of the "copolymer of styrenes and (meth)acrylate" and the "copolymer of styrenes, (meth)acrylate and (meth)acrylic acid" is The mass ratio is preferably in the range of 20:80 to 95:5, more preferably in the range of 30:70 to 92:8, and most preferably in the range of 40:60 to 90:10.

In the copolymer of styrenes and (meth)acrylate, the ratio of styrenes and (meth)acrylate is preferably in the range of 20:80 to 80:20, more preferably in the range of 30:70 to 70:30. More preferably, the range of 40:60 to 60:40 is most preferred.

In the copolymer of styrenes, (meth)acrylate and (meth)acrylic acid, the proportion of styrenes is preferably 10 to 90% by mass, more preferably 20 to 80% by mass, and 30 to 70% by weight is most preferred. Further, in the copolymer of styrenes, (meth)acrylate and (meth)acrylic acid, the proportion of (meth)acrylate is preferably 10 to 80% by mass, more preferably 15 to 70% by mass. Preferably, 20 to 60% by mass is most preferred. Further, in the copolymer of styrenes, (meth)acrylate and (meth)acrylic acid, the proportion of (meth)acrylic acid is preferably 10 to 70% by mass, more preferably 15 to 60% by mass. More preferably, it is most preferably 20 to 50% by mass.

When the styrene-acrylic copolymer (A) contains other known polymerizable compounds other than styrenes, (meth)acrylates, and (meth)acrylic acid, other polymerization in the styrene-acrylic copolymer (A) The ratio of the organic compound is preferably 10% by mass or less, more preferably 5% by mass or less.

The glass transition temperature (hereinafter sometimes referred to as Tg) of the styrene-acrylic copolymer (A) is in the range of -30°C to 10°C, preferably in the range of -25°C to 5°C, more preferably It ranges from -20°C to 0°C. In the present invention, the glass transition temperature is obtained by measurement with a differential scanning calorimeter.

A styrene-acrylic copolymer can be produced by a known method. Among them, it is preferable to polymerize the monomer mixture in the presence of wax for the styrene-acrylic copolymer. That is, by adding the wax to the aqueous medium in advance or mixing it with the monomer mixture, a core-shell structure in which the wax is incorporated into the styrene-acrylic copolymer can be formed.

(wax)
The waterproof coating composition can further improve the water resistance by containing a wax. The wax is preferably at least one wax selected from paraffin wax, microcrystalline wax, polyethylene oxide wax, and amide wax, more preferably paraffin wax or microcrystalline wax. These may be used alone or in combination.

The melting point of wax is preferably in the range of 30°C to 130°C, more preferably in the range of 50°C to 100°C. The blending amount of the wax is preferably 0.5 to 20% by mass, preferably 1 to 15% by mass, based on 100% by mass of the styrene-acrylic copolymer.

The wax may be dispersed in the water-resistant coating layer, but as described above, the presence of the wax in the core and/or shell of the styrene-acrylic copolymer allows the wax to be integrated with the styrene-acrylic copolymer. It is preferable to exist in a modified form. In the water-resistant coating layer, the wax may be present in the form of being contained in the styrene-acrylic copolymer and may be present without being contained in the styrene-acrylic copolymer.

(Other additives)
In addition to the above components, the waterproof coating composition may further contain silica, alumina, wax, antifoaming agent, leveling agent, tackifier, antiseptic agent, antibacterial agent, antirust agent, as long as the object of the present invention is not impaired. Additives such as may be blended. Moreover, other resins than the styrene-acrylic copolymer may be blended. Among them, it is preferable that a leveling agent and/or wax are further blended.

[Laminate production method]
The laminate of the present invention is prepared by sequentially applying the composition for forming the first layer and the composition for forming the second layer on the paper substrate, and if necessary, the composition for forming the third layer. Obtained by applying a substance.

Examples of methods for applying a coating composition onto a paper substrate include comma coaters, roll coaters, reverse roll coaters, direct gravure coaters, reverse gravure coaters, offset gravure coaters, roll kiss coaters, reverse kiss coaters, Kiss Gravure Coater, Reverse Kiss Gravure Coater, Air Doctor Coater, Knife Coater, Bar Coater, Wire Bar Coater, Die Coater, Lip Coater, Dip Coater, Blade Coater, Brush Coater, Curtain Coater, Die Slot Coater, Flexo Coater, Impregnation Coater , a cast coater, a spray coater, an offset printer, a screen printer, or the like, or a combination of two or more coating methods.

Alternatively, a resin layer may be provided on the paper substrate by impregnating the paper substrate with the composition. A drying step may be provided in an oven or the like after coating.

The water-resistant coating layer formed as described above has a first layer and a second layer. , the oil resistance can be further improved.

[Package or container]
Since the laminate of the present invention has a heat-sealable coat layer on either the first layer or the second layer, it can be used as a box or a bag by heat-sealing using the heat-sealable coat layer. , containers, etc.

Examples of packaging include packaging bags, paper bags, paper boxes, cardboard, wrapping paper, envelopes, cup sleeves, lids, and the like. Examples of containers include paper containers, paper plates, trays, cup holders, and paper cups. Due to the excellent water resistance and oil resistance of the present invention, it is preferably used for packaging materials for foods, fertilizers, and the like that require water resistance and oil resistance. For example, cups or lids for desserts such as cup noodles, ice cream, pudding, jelly, etc., bags or boxes for confectionery, grains, beans, powders, pet food, fertilizers, etc. Wrapping paper for hamburgers and hot dogs , pizza and other take-out containers, containers for hot snacks such as fried chicken and potatoes, food paper containers and packaging materials such as cups for side dishes such as natto, and hygiene products such as detergents and sanitary products and a bag or box.

For example, when producing a paper cup using the laminate of the present invention, the first layer and the second layer are provided on the inner surface of the container and the bonding portion when assembling the container, and the bonding portion is the first layer and the second layer. It can be manufactured by stacking and adhering via a second layer. That is, the paper cup consists of a body member (1) in which the laminated paper substrate of the laminate of the present invention is rolled and overlapped and the bonding surfaces of both ends are adhered, and a plate adhered to the lower end of the body member (1). The first layer and the second layer provided in the bonding portion are bonded by a heat sealing function, and the first layer and the second layer provided in the portion other than the bonding portion The second layer can exhibit the functions of water resistance and oil resistance. Since the first layer and the second layer provided on the portion other than the adhesive portion are highly safe to the human body and the environment, they can be accommodated in direct contact with food. Furthermore, by providing a water-resistant coating layer as a third layer on the outer side of the paper cup, excellent water resistance can be obtained even when used for a long time.

Similarly, paper boxes, paper bags, etc. can be manufactured by heat-sealing using the laminate of the present invention.

A specific method of heat sealing is to apply the first layer and the second layer to at least one of the two parts of the paper substrate (both parts may be applied), and then apply two layers. The two parts are overlapped and softened by heating. Heat sealing agents can be easily softened by heating with a burner or hot air, and can bond paper to paper or paper to other materials, and then cool to solidify the bonded portion, thereby bonding paper to paper or paper to other materials. It can be tightly sealed.

As the heating method, conventionally known means such as a heat source such as a burner, hot air, electric heat, infrared rays, and electron beams can be used. A heat welding sealing method, an ultrasonic sealing method, or a high frequency sealing method is preferable. The heating temperature at this time is preferably 200 to 500° C., and the heating time is preferably 0.1 to 3 seconds.

In addition, the heat sealing agent (HS) can be easily heated and softened even by non-contact heating, and can be softened to some extent even if it is separated from the heat source, in addition to the method of melting by contacting it directly with a heat source such as a heat sealing bar. The heat seal function lasts for hours. When the base material is paper, the paper may be scorched if it is brought into direct contact with a heat source. It is particularly useful as a heat sealing agent for industrial production of paper containers that require high line speed.

It can be used as a heat sealing agent by applying a heat sealing agent (HS) and heating and softening the coated portion, and then pressing the coated portion and another portion in a superimposed state. The crimping method is not particularly limited, and a hot plate method, ultrasonic sealing, or high-frequency sealing can be used.

The laminate of the present invention can prevent the first layer or the second layer including the heat-seal layer from adhering to the mold during heat-sealing in the manufacture of paper cups.

Although the present invention will be described in detail below based on examples, the technical scope of the present invention is not limited to these embodiments.

"Parts" in the following examples represent "parts by mass", and "%" represents "% by mass".

(Preparation of coating composition (CS) containing styrene acrylic copolymer (A))
100 parts of isopropyl alcohol was charged into a four-necked flask purged with nitrogen gas, the temperature was raised to 80 to 82° C., and then 1 part of myristyl acrylate, 30 parts of styrene, 10 parts of acrylic acid, and 5 parts of methyl methacrylate were charged to the dropping funnel. A mixture of 1 part of benzoyl peroxide and 1 part of benzoyl peroxide was added dropwise over 2 hours. After the dropwise addition, 0.5 part of benzoyl peroxide was added, and the reaction was further continued for 2 hours. The temperature was lowered to 40° C., and dimethylethanolamine and ion-exchanged water were added. Thereafter, the temperature of the reaction flask was raised to 80-82° C. and stripping was carried out to finally obtain a water-soluble resin with a solid content of 30%.

To the water-soluble resin obtained above, 10 parts of ion-exchanged water was charged in a reaction flask, the temperature was raised to 80 ° C. to 82 ° C., 2 parts of potassium persulfate were added, 15 parts of styrene and 5 parts of α-methylstyrene were added. , 24 parts of 2-ethylhexyl acrylate and 10 parts of butyl acrylate were added dropwise over 2 hours. After completion of dropping, 0.2 part of potassium persulfate was added and reacted for 2 hours. The acrylic emulsion (resin 1) thus obtained had a solid content of 40%, a minimum film-forming temperature of 1°C, a glass transition point of -27°C, and an acid value of the solid content of 64 mgKOH/g. .

A total of 100 parts of 85 parts of the acrylic emulsion (resin 1), 0.03 parts of a polymer-based antifoaming agent, and 14.97 parts of ion-exchanged water were thoroughly stirred at 25°C for 15 minutes with a disper to form a coating composition. (CS1) was produced.

(Adjustment of heat sealing agent (HS1))
Maleic acid-modified vinyl chloride/vinyl acetate copolymer (1 part of maleic acid/84 parts of vinyl chloride/15 parts of vinyl acetate) was mixed with 75 parts of a solvent having a mixing ratio of methyl ethyl ketone/ethyl acetate of 1:1. Then, using a dispersion stirrer, the solid content was gradually added to the solvent while stirring at a temperature of 25 ° C. and a rotation speed of 3000 rpm, and stirred for 10 minutes to obtain a vinyl chloride vinyl acetate copolymer resin heat sealant. (HS1) was produced.

(Adjustment of heat sealing agent (HS2))
38 parts of an acrylic resin (83 parts of methyl methacrylate/11 parts of butyl acrylate/1 part of 2-ethylhexyl acrylate/5 parts of methacrylic acid) and a neutralization rate of 100% with respect to the acid value of the copolymer Ammonia, water as an aqueous solvent, and 1.5 parts of polyethylene wax and 0.5 parts of paraffin wax as waxes were charged and stirred to prepare an acrylic resin heat sealing agent (HS2).

(Adjustment of heat sealing agent (HS3))
30 parts of an ethylene ethyl acrylate copolymer (77.8 parts of ethylene/11.1 parts of ethyl acrylate/11.2 parts of acrylic acid) and a neutralization rate of 100% with respect to the acid value of the copolymer. Ammonia, water as an aqueous solvent, and 1.5 parts of a fatty acid amide wax as a wax were charged, and isopropyl alcohol was further mixed and stirred so that the mixing ratio of water/isopropyl alcohol in the composition was 67/3. , an olefin-α,β unsaturated carboxylic acid copolymer heat sealing agent (HS3) was obtained.

(Adjustment of acrylic OP varnish (AOP1))
An aqueous acrylic emulsion (Dicksafe C-HP manufactured by DIC Corporation) was mixed with water and stirred to give an acrylic OP varnish (AOP1) so that the solid content was 30%.

<Creation of laminate>
(Examples 1 to 11, Comparative Examples 1 to 5)
Prepare a paper base material (pure white roll paper with a basis weight of 45 g / m ² (Kinshachi manufactured by Daio Paper Co., Ltd.), and on one side (rough surface side) of the paper base material for the first layer described in Table 1 A first layer was formed by applying and drying the composition to the film thickness shown in Table 1. Subsequently, the second layer for the second layer shown in Table 1 was formed on the first layer. The composition was applied to the film thickness shown in Table 1 and dried at 100° C. for 30 seconds using a dryer to prepare laminates of Examples 5 to 11.

In each layer, when CS1 or AOP1 is applied, it is dried for 20 seconds at 150°C using a dryer after application, and when HS1 to HS3 are applied, it is dried for 20 seconds at 150°C using a dryer after application. dried for a second.

<Evaluation>
(Heat sealability)
In the prepared laminates of Examples and Comparative Examples, the coated surface and the uncoated surface of the first layer and the second layer are overlapped, heated at a temperature in the range of 100 ° C. to 200 ° C., and immediately pressurized at 0.2 MPa, A heat-sealed portion was provided by using a heat-sealing machine under close contact conditions for 1 second. As for the state of adhesion, the strength of adhesion was evaluated from the state of occurrence of substrate damage such as paper peeling and paper tearing when the heat-sealed portion was peeled off. The temperature listed in the table is the lowest temperature at which substrate failure occurred.

(Oil resistance)
JAPAN TAPPI paper pulp test method No. using the laminates of the produced examples and comparative examples. Oil repellency was evaluated using the 41 kit method. In the evaluation, when the oil repellency was 7 or more, it was accepted (excellent), when it was 5 or more, it was acceptable, and when it was less than 4, it was not acceptable. The maximum oil repellency is 16.

(water resistant)
Tap water is collected with a dropper, and 0.1 ml is dropped onto the surface of the coated paper test piece for evaluation provided with the first layer and the second layer. After dropping, the sample was allowed to stand at 25° C., and the time until permeation to the back surface was observed was evaluated.

(mold peelability)
Aluminum was applied to the printed surface of the produced laminates of Examples and Comparative Examples, and sealing was performed with a heat sealer (0.2 Mpa, time of 1 second, width of 25 mm). After heat-sealing, the peel resistance when peeled off from the aluminum surface and the removal of the varnish are observed, and the temperature at which the varnish is removed by the aluminum is evaluated. The temperature in the table is the temperature at which the varnish was removed from the aluminum, but "100°C<" means that the varnish was removed from the aluminum at a temperature of 100°C or less.

The evaluation results are shown in the table below.

From the examples and comparative examples, it was found that the laminate having the first layer and the second layer of the present invention has excellent oil resistance and water resistance while having heat sealability. Further, as shown in Comparative Examples 1 to 3, it is not necessary to thickly apply the heat-sealing agent, and sufficient heat-sealing properties can be obtained.

When the second layer is a heat-sealable coating layer as shown in Examples 1 to 3, water resistance is higher than in Example 1 using HS3 (olefin-α, β unsaturated carboxylic acid copolymer system resin). Improved.

From Examples 1 to 6, the heat-sealing property was superior in Examples 1, 3, 4, and 6 using HS2 (polyolefin resin) and HS3 (olefin-α,β unsaturated carboxylic acid copolymer resin). was Further, as shown in Examples 7 to 9, the smaller the amount of coating on the paper, the better the adhesion at low temperatures. This is presumed to be due to the degree of penetration of the heat sealant into the paper.

We were able to confirm that the higher the heat seal temperature, the better the mold releasability. In Examples 4 and 4 in which the second layer was an oil- and water-resistant coating layer, there was a tendency for good mold releasability.

Claims

a paper substrate;
a first layer provided on at least a portion of the paper substrate;
Having at least a second layer provided on the first layer,
One of the first layer and the second layer is a coat layer containing a resin containing a styrene-acrylic copolymer of styrene, α-methylstyrene and (meth)acrylate, and the other contains a heat sealing agent. A laminate, characterized in that it is a coat layer that
In the styrene-acrylic copolymer, a styrene-acrylic copolymer of styrene, α-methylstyrene and (meth)acrylate and a copolymer of (meth)acrylic acid and (meth)acrylate form a core-shell structure. The laminate according to claim 1, characterized by:
The heat sealing agent is selected from vinyl chloride-vinyl acetate copolymer resin, (meth)acrylate resin, olefin-α,β unsaturated carboxylic acid copolymer resin, polyolefin resin and polyester resin. The laminate according to claim 1 or 2.
Laminate according to any one of the preceding claims, wherein the amount of said first layer is between 0.5 and 10.0 g/m 2 .
Laminate according to any one of the preceding claims, wherein the amount of said second layer is between 0.5 and 8.0 g/m 2 .
6. The method according to any one of claims 1 to 5, further comprising a third layer on the side of the paper base on which the first layer and the second layer are not provided, wherein the third layer is a waterproof coating layer. The laminate according to any one of the items.
A package or container in which at least a part of the coated portions of the first layer and the second layer is bonded using the laminate according to claims 1 to 6.
The package or container according to claim 7, wherein the coated portions of the first layer and the second layer are provided on the inner surface side of the package or container and are in direct contact with the contents.