Manufacturing method of laminates

Abstract

The present invention provides a method for manufacturing a laminate that exhibits excellent gas barrier properties after bending. [Solution] The method for manufacturing the laminate 1 includes the steps of preparing a paper substrate 10, forming a sealing layer 12 on at least one side of the paper substrate 10 by melt molding, and forming a gas barrier layer 14 on one side of the sealing layer 12. The sealing layer 12 contains a sealing resin. The sealing resin contains an olefin-(meth)acrylic acid copolymer and / or an olefin-(meth)acrylic acid copolymer ionomer.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing a laminate. [Background technology]

[0002] In recent years, laminates based on paper have been used from an environmental protection standpoint. For example, a paper laminate has been proposed that comprises a clay coat layer, an undercoat layer, a vapor deposition layer, an overcoat layer, and a heat seal layer in this order on at least one surface of the paper substrate. In the above paper laminate, the clay coat layer contains 67 parts by mass of kaolin as an inorganic pigment and 33 parts by mass of ethylene-acrylic acid copolymer as a binder (see, for example, Patent Document 1 (Comparative Example 3)). In the paper laminate described in Patent Document 1, the clay coat layer is formed by coating an aqueous coating solution in which clay and a water-suspended polymer are dispersed in an aqueous medium and drying it. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-169426 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, the paper laminate described in Patent Document 1 may not have sufficient gas barrier properties after bending.

[0005] This invention provides a method for manufacturing a laminate that exhibits excellent gas barrier properties after bending. [Means for solving the problem]

[0006] The present invention [1] is a method for producing a laminate, comprising the steps of preparing a paper substrate, forming a sealing layer on at least one side of the paper substrate by melt molding, and forming a gas barrier layer on one side of the sealing layer, wherein the sealing layer contains a sealing resin, and the sealing resin contains an olefin-(meth)acrylic acid copolymer and / or an olefin-(meth)acrylic acid copolymer ionomer.

[0007] The present invention [2] is a method for producing the laminate described in [1] above, wherein the sealing resin contains an olefin-(meth)acrylic acid copolymer.

[0008] The present invention [3] relates to a paper substrate with a basis weight of 180 g / m². 2 The method for manufacturing the laminate described in [1] or [2] above is as follows:

[0009] The present invention [4] relates to a laminate with a basis weight of 200 g / m². 2 The method for manufacturing a laminate described in any one of the above items [1] to [3] is as follows:

[0010] The present invention [5] is a method for producing a laminate according to any one of the above [1] to [4], wherein the gas barrier layer contains a gas barrier resin composition.

[0011] The present invention [6] is a method for manufacturing a laminate according to any one of the above [1] to [4], wherein the gas barrier layer comprises an inorganic vapor deposition layer.

[0012] The present invention [7] is a method for manufacturing a laminate according to any one of the above [1] to [6], further comprising the step of forming a heat seal layer on one side of the gas barrier layer. [Effects of the Invention]

[0013] According to the method for manufacturing a laminate of the present invention, it is possible to provide a laminate with excellent gas barrier properties after bending. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a schematic cross-sectional view showing Embodiment 1 of the laminate of the present invention. [Figure 2] Figures 2A to 2D are schematic cross-sectional views showing Embodiment 1 of the manufacturing method for the laminate of the present invention. Figure 2A shows the step of preparing a paper substrate. Figure 2B shows the step of forming a sealing layer on one side of the paper substrate. Figure 2C shows the step of forming a gas barrier layer on one side of the sealing layer. Figure 2D shows the step of forming a heat seal layer on one side of the gas barrier layer. [Figure 3] Figure 3 is a schematic cross-sectional view showing Embodiment 2 of the laminate of the present invention. [Figure 4] Figures 4A to 4D are schematic cross-sectional views showing Embodiment 2 of the method for manufacturing a laminate according to the present invention. Figure 4A shows the step of preparing a paper substrate. Figure 4B shows the step of forming a sealing layer on one side of the paper substrate. Figure 4C shows the step of forming a gas barrier layer on one side of the sealing layer. Figure 4D shows the step of forming a heat seal layer on one side of the gas barrier layer. [Modes for carrying out the invention]

[0015] <Embodiment 1> [Laminated structure] Referring to Figure 1, the laminate 1 of Embodiment 1 comprises a paper substrate 10, a sealing layer 12, and a gas barrier layer 14 in this order. The laminate 1 of Embodiment 1 has excellent gas barrier properties after bending. In the laminate 1 of Embodiment 1, as described later, the gas barrier layer 14 includes, for example, a gas barrier resin layer composition.

[0016] (1)Paper base material The paper substrate 10 is a substrate formed from paper. Examples of the paper substrate 10 include paper made from pulp. Examples of pulp include natural pulp and synthetic pulp. More specifically, examples of the paper substrate 10 include glassine paper, coated paper, single-sided gloss kraft paper, roll paper, and cup paper. The paper substrate 10 may be a single layer of paper or a multi-layer paper. The paper substrate 10 is appropriately selected according to the application of the laminate 1.

[0017] The shape of the paper substrate 10 is not particularly limited and is appropriately set. Examples of the shape of the paper substrate 10 include a sheet shape, a bottle shape, and a cup shape. Preferably, the shape of the paper substrate 10 is a sheet shape.

[0018] The paper substrate 10 may be surface-treated as needed. Examples of the surface treatment include corona treatment, surface coating treatment, and vapor deposition treatment.

[0019] The basis weight of the paper substrate 10 is, for example, 20 g / m 2 or more, preferably 40 g / m 2 or more, more preferably 60 g / m 2 or less. Also, the basis weight of the paper substrate 10 is, for example, 400 g / m 2 or less, preferably 250 g / m 2 or less, more preferably 200 g / m 2 or less, still more preferably 180 g / m 2 or less, still more preferably 140 g / m 2 or less, particularly preferably 120 g / m 2 or less, most preferably 100 g / m 2 or less.

[0020] (2) Sealing layer The sealing layer 12 is disposed on one side of the paper substrate 10, preferably on one surface of the paper substrate 10. That is, the sealing layer 12 is in contact with the paper substrate 10. The sealing layer 12 absorbs the irregularities on the surface of the paper substrate 10, smoothens the surface, and suppresses the penetration of a gas barrier coating material (described later) into the paper substrate 10.

[0021] The sealing layer 12 contains a sealing resin. The sealing layer 12 preferably consists of a sealing resin.

[0022] Furthermore, the sealing layer 12 is a melt-molded resin layer. That is, the sealing layer 12 is a melt-molded film obtained by melt-molding the sealing resin onto the surface of the paper substrate 10. More specifically, the sealing layer 12 is preferably an extruded film obtained by extruding the sealing resin onto the surface of the paper substrate 10.

[0023] In melt molding, the molten coating material is prepared as a block-like (solid) sealing resin. Preferably, the molten coating material is prepared as a sealing resin in a predetermined shape (e.g., pellet shape).

[0024] [Sealing resin] The sealing resin is, for example, a thermoplastic resin that can be melt-molded. In other words, the sealing resin is, for example, a thermoplastic resin.

[0025] The sealing resin contains an olefin-(meth)acrylic acid copolymer and / or an olefin-(meth)acrylic acid copolymer ionomer as essential components. That is, the sealing layer 12 contains an olefin-(meth)acrylic acid copolymer and / or an olefin-(meth)acrylic acid copolymer ionomer.

[0026] (Olefin-(meth)acrylic acid copolymer) Olefin-(meth)acrylic acid copolymers can be obtained, for example, by copolymerization of polymerization components containing olefin and (meth)acrylic acid.

[0027] In the polymerization component, the content of (meth)acrylic acid is, for example, 1% by mass or more, preferably 2% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, even more preferably 7% by mass or more, even more preferably 9% by mass or more, even more preferably 10% by mass or more, and particularly preferably 12% by mass or more, relative to the total amount of olefin and (meth)acrylic acid.

[0028] Furthermore, in the polymerization component, the content of (meth)acrylic acid is, for example, 30% by mass or less, preferably 20% by mass or less, and more preferably 15% by mass or less, relative to the total amount of olefin and (meth)acrylic acid.

[0029] In the polymerization component, the olefin content is, for example, 70% by mass or more, preferably 80% by mass or more, and more preferably 85% by mass or more, relative to the total amount of olefin and (meth)acrylic acid.

[0030] Furthermore, in the polymerization component, the olefin content is, for example, 99% by mass or less, preferably 98% by mass or less, more preferably 97% by mass or less, even more preferably 95% by mass or less, even more preferably 93% by mass or less, even more preferably 91% by mass or less, even more preferably 90% by mass or less, and particularly preferably 88% by mass or less, relative to the total amount of olefin and (meth)acrylic acid.

[0031] The polymerization component may contain other copolymerizable monomers. These other copolymerizable monomers are monomers other than olefins and (meth)acrylic acid, and are monomers copolymerizable with olefins and / or (meth)acrylic acid.

[0032] Other copolymerizable monomers include, for example, unsaturated esters. Examples of unsaturated esters include vinyl esters and unsaturated carboxylic acid esters. Examples of vinyl esters include vinyl acetate and vinyl propionate. Examples of unsaturated carboxylic acid esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isobutyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Further copolymerizable monomers include oxides, halogen compounds, vinyl group-containing primary and secondary amine compounds, carbon monoxide, and sulfur dioxide. Examples of oxides include vinyl sulfuric acid and vinyl nitric acid. Examples of halogen compounds include vinyl chloride and vinyl fluoride. These can be used individually or in combination of two or more. Other copolymerizable monomers preferably include unsaturated esters, and more preferably unsaturated carboxylic acid esters.

[0033] The proportion of other copolymerizable monomers is, for example, 0% by mass or more relative to the polymerization component. Furthermore, the proportion of other copolymerizable monomers is, for example, 30% by mass or less, more preferably 25% by mass or less, relative to the polymerization component.

[0034] In other words, the total amount of olefin and (meth)acrylic acid is, for example, 70% by mass or more, preferably 75% by mass or more, relative to the polymerization component. Also, the total amount of olefin and (meth)acrylic acid is 100% by mass or less relative to the polymerization component.

[0035] Olefin-(meth)acrylic acid copolymers are obtained by copolymerizing polymerization components in a predetermined ratio using a known polymerization method.

[0036] Examples of olefin-(meth)acrylic acid copolymers include copolymers of an olefin having 2 to 20 carbon atoms, (meth)acrylic acid, and (other copolymerizable monomers as needed), preferably copolymers of the above-mentioned olefin having 2 or 3 carbon atoms, (meth)acrylic acid, and (other copolymerizable monomers as needed), and more preferably copolymers of ethylene, (meth)acrylic acid, and (other copolymerizable monomers as needed).

[0037] Olefin-(meth)acrylic acid copolymers have polymerization units derived from olefins and polymerization units derived from (meth)acrylic acid. Furthermore, olefin-(meth)acrylic acid copolymers may also have polymerization units derived from other copolymerizable monomers.

[0038] Polymerization units derived from (meth)acrylic acid have unneutralized (described later) carboxyl groups (i.e., free acid). Hereafter, the proportion of polymerization units derived from (meth)acrylic acid will be referred to as the acid content.

[0039] The content of polymerization units derived from (meth)acrylic acid (acid content) is, for example, 1% by mass or more relative to the total amount of the olefin-(meth)acrylic acid copolymer. Furthermore, the content of polymerization units derived from (meth)acrylic acid (acid content) is, for example, 30% by mass or less relative to the total amount of the olefin-(meth)acrylic acid copolymer.

[0040] The content of polymerization units derived from (meth)acrylic acid (acid content) is preferably 2% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, even more preferably 7% by mass or more, even more preferably 9% by mass or more, even more preferably 10% by mass or more, and particularly preferably 12% by mass or more, relative to the total amount of the olefin-(meth)acrylic acid copolymer. In Embodiment 1, the content of polymerization units derived from (meth)acrylic acid (acid content) is preferably 20% by mass or less, more preferably 15% by mass or less, relative to the total amount of the olefin-(meth)acrylic acid copolymer.

[0041] In olefin-(meth)acrylic acid copolymers, the proportion of polymerization units derived from (meth)acrylic acid (acid content) is measured by the following method. Specifically, the proportion of (meth)acrylic acid relative to the total amount of olefin and (meth)acrylic acid in the raw materials of the olefin-(meth)acrylic acid copolymer can be calculated as the acid content (the same applies hereafter). The acid content can also be measured by nuclear magnetic resonance (NMR) spectroscopy (the same applies hereafter).

[0042] The glass transition temperature (Tg) of the olefin-(meth)acrylic acid copolymer is, for example, -10°C or higher, from the viewpoint of bending resistance. Furthermore, the glass transition temperature (Tg) of the olefin-(meth)acrylic acid copolymer is, for example, 70°C or lower, from the viewpoint of adhesion.

[0043] The glass transition temperature (Tg) of the olefin-(meth)acrylic acid copolymer is preferably -6°C or higher, more preferably 0°C or higher, even more preferably 10°C or higher, even more preferably 20°C or higher, even more preferably 26°C or higher, and particularly preferably 28°C or higher. In Embodiment 1, the glass transition temperature (Tg) of the olefin-(meth)acrylic acid copolymer is preferably 50°C or lower, more preferably 40°C or lower, and even more preferably 30°C or lower.

[0044] The glass transition temperature (Tg) is measured by the following method: the peak temperature of tanδ in the dynamic viscoelasticity measurement can be calculated as the glass transition temperature (Tg) (the same applies hereafter).

[0045] (Olefin-(meth)acrylic acid copolymer ionomer) Olefin-(meth)acrylic acid copolymer ionomers are obtained by neutralizing the carboxyl groups of the above-described olefin-(meth)acrylic acid copolymer with a monovalent metal and / or a divalent metal. As described above, the carboxyl groups are the carboxyl groups of the polymerization units derived from (meth)acrylic acid. That is, olefin-(meth)acrylic acid copolymer ionomers have polymerization units derived from (meth)acrylic acid that have been neutralized.

[0046] Examples of monovalent metals include sodium and potassium, with sodium being preferred from the viewpoint of ease of manufacture. Examples of divalent metals include magnesium, zinc, calcium, copper, iron, and barium, with zinc being preferred from the viewpoint of ease of manufacture.

[0047] To neutralize the carboxyl groups of the olefin-(meth)acrylic acid copolymer with a monovalent metal and / or a divalent metal, the olefin-(meth)acrylic acid copolymer is mixed with a compound containing a monovalent metal and / or a compound containing a divalent metal.

[0048] Examples of compounds containing a monovalent metal include the hydroxide of the monovalent metal, preferably sodium hydroxide. Examples of compounds containing a divalent metal include the oxide, hydroxide, and carbide of the divalent metal, preferably the hydroxide of the divalent metal, and more preferably zinc hydroxide.

[0049] The metal that neutralizes the ionomer resin comprises a monovalent metal and / or a divalent metal, preferably comprising a monovalent metal or a divalent metal, and more preferably comprising only a monovalent metal or only a divalent metal.

[0050] Such ionomers neutralized with a monovalent metal and / or a divalent metal are preferably, from the viewpoint of adhesion, ionomers neutralized with a monovalent metal or ionomers neutralized with a divalent metal, more preferably ionomers neutralized with sodium or ionomers neutralized with zinc.

[0051] In other words, olefin-(meth)acrylic acid copolymer ionomers have polymerization units derived from (meth)acrylic acid and neutralized with monovalent and / or divalent metals.

[0052] The content of neutralized polymerization units derived from (meth)acrylic acid is, for example, 1% by mass or more and 30% by mass or less, relative to the total amount of the olefin-(meth)acrylic acid copolymer ionomer. The content of neutralized polymerization units derived from (meth)acrylic acid is calculated by a known method.

[0053] From the viewpoint of bending resistance, the glass transition temperature (Tg) of the olefin-(meth)acrylic acid copolymer ionomer is, for example, 0°C or higher, preferably 10°C or higher, more preferably 20°C or higher, and even more preferably 30°C or higher. Furthermore, from the viewpoint of adhesion, the glass transition temperature (Tg) of the olefin-(meth)acrylic acid copolymer ionomer is, for example, 70°C or lower, preferably 60°C or lower, more preferably 50°C or lower, and even more preferably 40°C or lower.

[0054] From the viewpoint of gas barrier properties after bending, olefin-(meth)acrylic acid copolymers and / or olefin-(meth)acrylic acid copolymer ionomers are preferably olefin-(meth)acrylic acid copolymers. That is, from the viewpoint of gas barrier properties after bending, the sealing resin preferably contains an olefin-(meth)acrylic acid copolymer, and more preferably consists of an olefin-(meth)acrylic acid copolymer.

[0055] (Other resins) The sealing resin may contain other resins as optional components, if necessary. That is, the sealing layer 12 may contain other resins as optional components.

[0056] Other resins are those excluding the olefin-(meth)acrylic acid copolymer and the olefin-(meth)acrylic acid copolymer ionomer mentioned above. Examples of other resins include polyurethane, polyolefin, and acid-modified polyolefin.

[0057] (Polyurethane) Examples of polyurethanes include thermoplastic polyurethanes. Examples of thermoplastic polyurethanes include reaction products of a pore-sealing polyisocyanate component and a pore-sealing active hydrogen group-containing component.

[0058] Examples of polyisocyanate components for sealing include industrially common polyisocyanates. More specifically, examples of polyisocyanate components for sealing include linear aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and aromatic aliphatic polyisocyanates.

[0059] Examples of linear aliphatic polyisocyanates include pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), and their derivatives. Examples of alicyclic polyisocyanates include isophorone diisocyanate (IPDI), norbornene diisocyanate (NBDI), and 4,4'-methylenebis(cyclohexyl isocyanate) (H 12Examples of polyisocyanates include MDI, bis(isocyanatomethyl)cyclohexane (H6XDI), and their derivatives. Examples of aromatic polyisocyanates include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and their derivatives. Examples of aromatic aliphatic polyisocyanates include xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), and their derivatives.

[0060] Examples of derivatives include polymers, isocyanurate-modified derivatives, allophanate-modified derivatives, polyol-modified derivatives, biuret-modified derivatives, urea-modified derivatives, oxadiazinetrione-modified derivatives, and carbodiimide-modified derivatives. These can be used individually or in combination of two or more types.

[0061] Preferably, the polyisocyanate component for sealing is an alicyclic polyisocyanate, and more preferably, bis(isocyanatomethyl)cyclohexane (H6XDI). Examples of bis(isocyanatomethyl)cyclohexane include 1,3-bis(isocyanatomethyl)cyclohexane and 1,4-bis(isocyanatomethyl)cyclohexane, and preferably, 1,4-bis(isocyanatomethyl)cyclohexane.

[0062] Examples of active hydrogen group-containing components for sealing include polyols. Examples of polyols include high molecular weight polyols and low molecular weight polyols.

[0063] High molecular weight polyols are, for example, polyols with a number average molecular weight of 400 to 20,000. Examples of high molecular weight polyols include polyether polyols, polyester polyols, polycarbonate polyols, polyurethane polyols, epoxy polyols, vegetable oil polyols, polyolefin polyols, acrylic polyols, and vinyl monomer-modified polyols.

[0064] Low molecular weight polyols are, for example, polyols with a number average molecular weight of 40 or more and less than 400 (preferably less than 300). Examples of low molecular weight polyols include dihydric alcohols, trihydric alcohols, and tetrahydric or higher alcohols. Examples of dihydric alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, and dipropylene glycol. Examples of trihydric alcohols include glycerin and trimethylolpropane. Examples of tetrahydric or higher alcohols include pentaerythritol and diglycerin. These can be used individually or in combination of two or more.

[0065] Thermoplastic polyurethanes are obtained by reacting a pore-sealing polyisocyanate component with a pore-sealing active hydrogen group-containing component using a known method. The reaction method between the pore-sealing polyisocyanate component and the pore-sealing active hydrogen group-containing component is not particularly limited and includes, for example, a one-shot method and a prepolymer method. The pore-sealing polyisocyanate component and the pore-sealing active hydrogen group-containing component may be reacted in the presence of a known reaction solvent, if necessary. Furthermore, a known urethane catalyst may be added to the reaction between the pore-sealing polyisocyanate component and the pore-sealing active hydrogen group-containing component, if necessary.

[0066] (Polyolefin) Examples of polyolefins include polymers of olefins having 2 to 20 carbon atoms.

[0067] Examples of olefins having 2 to 20 carbon atoms include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene, with ethylene and / or propylene being preferred.

[0068] Polyolefins include polyethylene and / or polypropylene. Polyethylenes include high-density polyethylene, medium-density polyethylene, low-density polyethylene, and ultra-low-density polyethylene, with low-density polyethylene being preferred. Low-density polyethylenes include linear low-density polyethylene. Polypropylenes include three types based on differences in stereoregularity: isotactic, syndiotactic, and atactic (random), with atactic (random) polypropylene being preferred.

[0069] Polymers of olefins having 2 to 20 carbon atoms can be obtained by polymerizing olefins having 2 to 20 carbon atoms using known methods. For example, the polymerization method involves polymerizing α-olefins having 2 to 20 carbon atoms in the presence of a metallocene catalyst.

[0070] (Acid-modified polyolefin) Acid-modified polyolefins can be obtained, for example, by modifying the above-mentioned polyolefins with an acidic component. The acidic component may have, for example, a carboxyl group or an acid anhydride group.

[0071] Preferably, the acid component is an unsaturated carboxylic acid or an unsaturated carboxylic acid anhydride. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, and citraconic acid. Examples of unsaturated carboxylic acid anhydrides include maleic anhydride, itaconic anhydride, citraconic anhydride, and tetrahydrophthalic anhydride, with maleic anhydride being preferred.

[0072] The modification of an acid-modified polyolefin with an acid component is carried out, for example, by first dissolving the polyolefin in a known organic solvent (e.g., toluene). Then, a known radical generator is added, and the mixture is heated and stirred.

[0073] The heating temperature is, for example, 50°C to 250°C, preferably 80°C to 200°C, and more preferably 120°C to 190°C. The reaction time is, for example, 1 minute to 10 hours.

[0074] As a result, the acid component undergoes graft polymerization on the above-mentioned polyolefin, yielding an acid-modified polyolefin. The content of constituent units derived from the acid component is 0.2% to 1.2% by mass, preferably 0.3% to 1.1% by mass, more preferably 0.4% to 1.0% by mass, and even more preferably 0.5% to 0.9% by mass, relative to the acid-modified polyolefin.

[0075] (Percentage of other resins) Other resins can be used alone or in combination of two or more types. The proportion of other resins will be set appropriately according to the purpose and application.

[0076] The content of other resins is, for example, 30% by mass or less, preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably 0% by mass, relative to the total amount of sealing resin.

[0077] In other words, the content of the olefin-(meth)acrylic acid copolymer and / or the olefin-(meth)acrylic acid copolymer ionomer (the total amount if used in combination) is, for example, 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass, relative to the total amount of the sealing resin.

[0078] In other words, the sealing resin is particularly preferably free of other resins and consists of an olefin-(meth)acrylic acid copolymer and / or an olefin-(meth)acrylic acid copolymer ionomer.

[0079] (Percentage of sealing resin content) The content of the sealing resin relative to the total amount of the sealing layer 12 is, for example, 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 100% by mass. That is, the sealing layer 12 is particularly preferably made of a sealing resin.

[0080] Furthermore, the content ratio of the olefin-(meth)acrylic acid copolymer and / or the olefin-(meth)acrylic acid copolymer ionomer (total amount if used in combination) relative to the total amount of the sealing layer 12 is, for example, 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass. That is, the sealing layer 12 is particularly preferably composed of an olefin-(meth)acrylic acid copolymer and / or an olefin-(meth)acrylic acid copolymer ionomer.

[0081] (Melting point of sealing resin) From the viewpoint of melt molding under suitable conditions, the melting point of the sealing resin is, for example, 60°C or higher, preferably 80°C or higher, more preferably 90°C or higher, and also, for example, 300°C or lower, preferably 250°C or lower, more preferably 225°C or lower, and even more preferably 200°C or lower.

[0082] (Meltmass flow rate of sealing resin) The melt mass flow rate (MFR) of the sealing resin is, from the viewpoint of melt molding under suitable conditions, for example, 0.5 g / 10 min or more, preferably 1.0 g / 10 min or more, more preferably 2.0 g / 10 min or more, and even more preferably 4.0 g / 10 min or more, and also, for example, 30 g / 10 min or less, preferably 25 g / 10 min or less, more preferably 15 g / 10 min or less, and even more preferably 10 g / 10 min or less. The MFR of the sealing resin is measured in accordance with JIS K7210-1:2014. For the melt mass flow rate (MFR) of olefin-(meth)acrylic acid copolymer and olefin-(meth)acrylic acid copolymer ionomer, the measurement temperature is 190°C and the measurement load is 2.16 kg.

[0083] [Additives] (Types of additives) The sealing layer 12 may contain additives in addition to the sealing resin. Examples of additives include fillers, thickening inhibitors, heat stabilizers, antioxidants, light stabilizers, UV absorbers, plasticizers, antistatic agents, lubricants, antiblocking agents, pigments, dyes, nucleating agents, and curing agents. These can be used individually or in combination of two or more types.

[0084] (Percentage of additives) The additive content is, for example, 0% by mass or more relative to the total amount of the sealing layer 12. Alternatively, the additive content is, for example, 30% by mass or less, preferably 20% by mass or less, more preferably 10% by mass or less, and particularly preferably 0% by mass, relative to the total amount of the sealing layer 12. In other words, the sealing layer 12 is particularly preferably free of additives.

[0085] [Basis weight of sealing layer] The basis weight of the sealing layer 12 is, for example, 1.5 g / m². 2 The above is preferable, preferably 3.0 g / m 2 That is all, and also, for example, 30.0 g / m 2 The following, preferably 20.0 g / m² 2 The following, and more preferably 15.0 g / m² 2The following, and more preferably 10 g / m² 2 The following is particularly preferred: 6 g / m 2 The following applies:

[0086] (3) Gas barrier layer The gas barrier layer 14 is positioned on one side of the sealing layer 12, preferably on one surface of the sealing layer 12. That is, the gas barrier layer 14 is preferably in contact with the sealing layer 12. The gas barrier layer 14 is a layer having gas barrier properties and ensures the gas barrier properties of the laminate 1.

[0087] The gas barrier property of the gas barrier layer 14 refers to its property of reducing oxygen permeability. More specifically, the gas barrier layer 14 contains a gas barrier resin composition having an oxygen permeability of a predetermined value or less, and preferably consists of a gas barrier resin composition. For example, a basis weight of 10 g / m². 2 The oxygen permeability of the gas barrier layer 14 is, for example, 1 (cc / (m³) at room temperature. 2 The value is less than or equal to (day·atm). Oxygen permeability is measured in accordance with Method B of JIS K7126:2006, using an oxygen permeability measuring device (MOCON, OX-TRAN2 / 22H). Measurement conditions are 20°C and 80%RH (relative humidity).

[0088] The gas barrier layer 14 is formed by applying and drying a gas barrier coating material to the surface of the sealing layer 12. The gas barrier coating material includes a gas barrier resin composition. The gas barrier coating material may contain the additives described above.

[0089] [Gas barrier resin composition] A gas barrier resin composition includes, for example, a resin and a layered inorganic compound dispersed in the resin.

[0090] (resin) Examples of resins include polyurethane resins, acrylic resins, polyolefin resins, and polyvinyl alcohol resins, with polyurethane resins and polyvinyl alcohol resins being preferred, and polyurethane resins being more preferred. In particular, from the viewpoint of improving the overall gas barrier properties (gas barrier properties against oxygen and water vapor) of the gas barrier layer, polyurethane resins are preferred, and gas barrier polyurethane resins are even more preferred.

[0091] Polyvinyl alcohol resin has lower oxygen permeability before and after bending compared to polyurethane resin, but higher water vapor permeability before bending. In other words, polyurethane resin has higher gas barrier properties against both oxygen and water vapor compared to polyvinyl alcohol resin.

[0092] The gas barrier polyurethane resin contains, for example, a reaction product of an isocyanate group-terminated prepolymer and a chain extender, and preferably consists of a reaction product of an isocyanate group-terminated prepolymer and a chain extender. The isocyanate group-terminated prepolymer contains, for example, a reaction product of a gas barrier polyisocyanate component and a gas barrier active hydrogen group-containing component, and preferably consists of a reaction product of a gas barrier polyisocyanate component and a gas barrier active hydrogen group-containing component.

[0093] Examples of polyisocyanate components for gas barriers include known polyisocyanate components. From the viewpoint of gas barrier properties, the polyisocyanate component preferably contains xylylene diisocyanate (XDI) and / or bis(isocyanatomethyl)cyclohexane (H6XDI). In addition, the polyisocyanate component may optionally contain other polyisocyanates (polyisocyanates other than xylylene diisocyanate and bis(isocyanatomethyl)cyclohexane).

[0094] The polyisocyanate component for gas barriers preferably contains xylylene diisocyanate (XDI) and / or bis(isocyanatomethyl)cyclohexane (H6XDI) and other polyisocyanates (preferably methylenebis(cyclohexyl isocyanate)). The proportions of these components are set appropriately depending on the purpose and application.

[0095] The active hydrogen group-containing component for gas barriers is an organic compound containing an active hydrogen group. Examples of active hydrogen groups include hydroxyl groups and amino groups, with hydroxyl groups being preferred. Examples of active hydrogen group-containing components for gas barriers include known active hydrogen group-containing compounds. From the viewpoint of gas barrier properties, the active hydrogen group-containing component for gas barriers preferably contains an active hydrogen group-containing compound that contains a short-chain diol having 2 to 6 carbon atoms and an anionic group.

[0096] Short-chain diols having 2 to 6 carbon atoms are organic compounds having 2 to 6 carbon atoms and possessing two hydroxyl groups in one molecule. Examples of short-chain diols include alkanediols having 2 to 6 carbon atoms and etherdiols having 2 to 6 carbon atoms, preferably alkanediols having 2 to 6 carbon atoms, and more preferably ethylene glycol.

[0097] Furthermore, active hydrogen group-containing compounds for gas barriers may also contain triols. Examples of triols include trimethylolpropane.

[0098] Preferably, organic compounds containing anionic groups and active hydrogen groups include organic compounds having one carboxyl group and two or more hydroxyl groups in one molecule, and more preferably, organic compounds having one carboxyl group and two hydroxyl groups in one molecule. Preferably, organic compounds having one carboxyl group and two hydroxyl groups include polyhydroxyalkanoic acid, and even more preferably, 2,2-dimethylolpropionic acid.

[0099] The isocyanate-terminated prepolymer is obtained by reacting the above components in a predetermined equivalence ratio using a known polymerization method. The equivalence ratio (isocyanate group / active hydrogen group) is, for example, 1.1 or more and 10 or less. Preferably, a known neutralizing agent is added to neutralize the carboxyl group.

[0100] Chain elongators are organic compounds that cause chain elongation reactions in isocyanate-terminated prepolymers. Chain elongators have multiple active hydrogen groups. Examples of chain elongators include polyamines, amino group-containing alkoxysilyl compounds, and amino alcohols (e.g., 2-(2-aminoethylamino)ethanol, diethanolamine (DEA)), and diamines (e.g., ethylenediamine (EDA)).

[0101] To react the isocyanate-terminated prepolymer with the chain extender, for example, first, the isocyanate-terminated prepolymer is dispersed in water by adding it to water, and then the chain extender is added to extend the chains of the isocyanate-terminated prepolymer. The equivalent ratio of the chain extender to the isocyanate-terminated prepolymer (active hydrogen group / isocyanate group) is, for example, 0.6 to 1.2. This yields a gas barrier polyurethane resin, and a dispersion (polyurethane dispersion) is prepared in which the gas barrier polyurethane resin is dispersed in water.

[0102] (Layered inorganic compounds) Examples of layered inorganic compounds include swellable layered inorganic compounds and non-swellable layered inorganic compounds. From the viewpoint of gas barrier properties, swellable layered inorganic compounds are preferred.

[0103] Swellable layered inorganic compounds are clay minerals consisting of extremely thin unit crystals, in which solvents coordinate or absorb and swell between the unit crystal layers.

[0104] Examples of swellable layered inorganic compounds include, for example, hydrated silicates (phyllosilicate minerals, etc.), kaolinite clay minerals (haloysite, kaolinite, endelite, dickite, nacrite, etc.), antigorite clay minerals (antigorite, chrysotile, etc.), smectite clay minerals (montmorillonite, bydelite, nontronite, saponite, hectorite, souconite, stevensite, etc.), vermiculite clay minerals (vermiculite, etc.), mica or mica clay minerals (muscovite, phlogopite, etc., margalite, tetrasilicic mica, teniolite, etc.), and synthetic mica.

[0105] These swellable layered inorganic compounds may be natural clay minerals or synthetic clay minerals. They can be used alone or in combination of two or more. Preferably, examples include smectite group clay minerals (such as montmorillonite), mica group clay minerals (such as water-swellable mica), and synthetic mica, with synthetic mica being more preferred.

[0106] Then, a layered inorganic compound is blended with the above-mentioned gas barrier polyurethane resin to obtain a gas barrier resin composition. Specifically, a layered inorganic compound is blended with the above-mentioned polyurethane dispersion to prepare a gas barrier coating material.

[0107] (Mass ratio of resin to layered inorganic compound in gas barrier resin composition) The proportion of resin in the gas barrier resin composition is, from the viewpoint of maintaining high gas barrier properties of the gas barrier layer, for example, 35 parts by mass or more, preferably 45 parts by mass or more, more preferably 55 parts by mass or more, and also, for example, 95 parts by mass or less, preferably 85 parts by mass or less, and more preferably 80 parts by mass or less, per 100 parts by mass of the gas barrier resin composition (solids). The proportion of layered inorganic compound in the gas barrier resin composition is, from the viewpoint of maintaining high gas barrier properties of the gas barrier layer, for example, 5 parts by mass or more, preferably 15 parts by mass or more, more preferably 20 parts by mass or more, per 100 parts by mass of the gas barrier resin composition (solids), and also, for example, 65 parts by mass or less, preferably 55 parts by mass or less, and more preferably 45 parts by mass or less.

[0108] [Basis volume of gas barrier layer] The basis weight of the gas barrier layer 14 is, for example, 0.2 g / m². 2 Preferably 0.5 g / m 2 Above all, a comfortable 1.0 g / m 2 That's all, and also, for example, 10g / m 2 Preferably 7.0 g / m 2 More preferably, 5.0 g / m 2 The following applies:

[0109] (4) Heat seal layer The laminate 1 may further include a heat seal layer 16. The heat seal layer 16 is located on one side of the gas barrier layer 14, preferably on one surface of the gas barrier layer 14. That is, the heat seal layer 16 is preferably in contact with the gas barrier layer 14. The heat seal layer 16 is a heat-sealable layer and ensures the heat sealability of the laminate 1. In addition, the presence of the heat seal layer 16 improves the gas barrier properties of the laminate 1 after bending.

[0110] The heat seal layer 16 is formed by applying and drying a heat sealable coating material on the surface of the gas barrier layer 14. The heat sealable coating material includes a heat sealable resin.

[0111] [Heat-sealable resin] A heat-sealable resin is a resin that can be heat-sealed (heat-fused) to one another. The heat-sealable resin is not particularly limited, and known heat-sealable resins can be used. More specifically, examples of heat-sealable resins include polyolefins, (meth)acrylic resins (including ethylene-(meth)acrylic acid copolymers and ethylene-(meth)acrylate alkyl ester-(meth)acrylic acid copolymers), and the polyurethanes mentioned above. These can be used individually or in combination of two or more types.

[0112] Heat-sealable coating materials are prepared as an organic solvent solution of a heat-sealable resin or as an aqueous dispersion of a heat-sealable resin. For example, to prepare an aqueous dispersion, in the case of acrylic resins, an olefin-(meth)acrylic acid copolymer or an olefin-(meth)acrylate alkyl ester-(meth)acrylic acid copolymer is dispersed in water. Alternatively, a carboxylic acid-modified acrylic resin can be prepared by copolymerizing (meth)acrylic acid with an (meth)acrylate alkyl ester, and then dispersed in water. Furthermore, two or more resins selected from acrylic resins can be melt-kneaded and then dispersed in water. Specifically, olefin-(meth)acrylic acid copolymers and olefin-(meth)acrylate alkyl ester-(meth)acrylic acid copolymers can be melt-kneaded and then dispersed in water.

[0113] Furthermore, the heat-sealable coating material may contain the additives described above. Furthermore, the heat seal layer can also be formed by laminating the polyolefin film described above onto the gas barrier layer 14 via a known adhesive.

[0114] [Basis weight of the heat seal layer] The basis weight of the heat seal layer 16 is, for example, 0.5 g / m². 2 Preferably 1.0 g / m 2 More preferably 2.0 g / m 2 The above is true, and more preferably 5.0 g / m 2 That's all, and also, for example, 20g / m2 Preferably 10 g / m 2 The following applies:

[0115] [Basis weight of laminated material] The basis weight of laminate 1 is, for example, 25 g / m², from the viewpoint of gas barrier properties. 2 Preferably 45 g / m² 2 More than 65g / m 2 That concludes the explanation. Furthermore, the basis weight of laminate 1 should be, for example, 435 g / m², from the viewpoint of heat sealability. 2 Preferably 285 g / m² 2 More preferably 235 g / m² 2 More preferably 200 g / m 2 More preferably, 180 g / m² 2 More preferably 160 g / m 2 More preferably 150 g / m 2 The following is particularly preferred: 120 g / m² 2 Below, most preferably 100 g / m 2 The following applies:

[0116] [Method for manufacturing laminates] Referring to Figure 2, the manufacturing method of the laminate 1 of Embodiment 1 includes the steps of preparing a paper substrate 10 (Figure 2A), forming a sealing layer 12 on one side of the paper substrate 10 by melt molding (Figure 2B), forming a gas barrier layer 14 on one side of the sealing layer 12 (Figure 2C), and further including the step of forming a heat seal layer 16 on one side of the gas barrier layer 14 (Figure 2D). The manufacturing method of the laminate of Embodiment 1 can produce a laminate 1 with excellent gas barrier properties after bending.

[0117] (Process of preparing paper substrate) As shown in Figure 2A, prepare the paper substrate 10.

[0118] (Process of forming a sealing layer by melt molding) As shown in Figure 2B, a sealing layer 12 is formed on one side of the paper substrate 10 by melt molding. Preferably, the sealing layer 12 is formed on one surface of the paper substrate 10 by melt molding.

[0119] The melt molding method is not particularly limited as long as it can be used to melt and mold a thermoplastic resin. Examples include extrusion molding, injection molding, insert molding, blow molding, compression molding, and transfer molding, with extrusion molding being preferred. The extrusion method in extrusion molding is not particularly limited, and examples include unscrew extrusion and twin-screw extrusion. Specifically, an extrusion laminator equipped with an unscrew extruder and dies is used to extrude a molten coating material onto the surface of a paper substrate 10, thereby forming a sealing layer 12 on the surface of the paper substrate 10, thereby performing extrusion coating.

[0120] The following conditions can be cited as requirements for the extrusion coating process. • Die-under resin temperature: Above the melting point of the sealing resin, for example, 150°C or higher, preferably 200°C or higher, more preferably 220°C or higher, even more preferably 250°C or higher, and also, for example, 350°C or lower, preferably 320°C or lower.

[0121] If the resin temperature under the die is above the lower limit, excellent adhesive strength, as well as excellent ductility and high-speed processing capabilities, can be obtained. Furthermore, if the resin temperature under the die is below the upper limit, resin degradation can be suppressed, and the generation of gel, smoke, and odor can also be suppressed.

[0122] In extrusion coating processes, preferably, in order to improve the adhesive strength between the molten coating material and the paper substrate, the surface of the molten coating material that comes into contact with the paper substrate is treated with ozone, and the surface of the paper substrate that comes into contact with the molten coating material is treated with corona.

[0123] (Process for forming a gas barrier layer) As shown in Figure 2C, a gas barrier layer 14 is formed on one side of the sealing layer 12. Preferably, the gas barrier layer 14 is formed on one surface of the sealing layer 12.

[0124] There are no particular restrictions on the method for forming the gas barrier layer 14, but from the viewpoint of forming the gas barrier layer 14 simply and efficiently, it is formed by applying and drying a gas barrier coating material on one surface of the sealing layer 12.

[0125] The method of applying the gas barrier coating agent is not particularly limited, and known coating methods such as gravure coating, reverse coating, roll coating, bar coating, spray coating, air knife coating, and dipping can be used. It can also be applied in-line following the formation of the sealing layer 12.

[0126] Furthermore, the drying conditions include a drying temperature of, for example, 40°C or higher, preferably 50°C or higher, more preferably 90°C or higher, and for example, 200°C or lower, preferably 180°C or lower, and more preferably 150°C or lower. The drying time is, for example, 0.1 minutes or more, preferably 0.2 minutes or more, and for example, 10 minutes or less, preferably 5 minutes or less.

[0127] This allows a gas barrier layer 14 to be formed on the surface of the sealing layer 12.

[0128] (Process for forming a heat seal layer) As shown in Figure 2D, a heat seal layer 16 is formed on one side of the gas barrier layer 14. Preferably, the heat seal layer 16 is formed on one surface of the gas barrier layer 14.

[0129] There are no particular restrictions on the method for forming the heat seal layer 16, but from the viewpoint of forming a heat seal simply and efficiently, it is formed by applying and drying a heat sealable coating material containing a heat sealable resin on one surface of the gas barrier layer 14.

[0130] The method of applying the heat-sealable coating agent is not particularly limited and includes known coating methods such as gravure coating, reverse coating, roll coating, bar coating, spray coating, air knife coating, and dipping. It can also be applied in-line following the formation of the gas barrier layer.

[0131] Furthermore, the drying conditions include a drying temperature of, for example, 40°C or higher, preferably 50°C or higher, more preferably 90°C or higher, and for example, 200°C or lower, preferably 180°C or lower, and more preferably 150°C or lower. The drying time is, for example, 0.1 minutes or more, preferably 0.2 minutes or more, and for example, 10 minutes or less, preferably 5 minutes or less.

[0132] This allows a heat seal layer 16 to be formed on the surface of the gas barrier layer 14.

[0133] This yields laminate 1. The laminate 1 exhibits excellent gas barrier properties after bending.

[0134] In the manufacturing method of the laminate according to Embodiment 1 of the present invention, a sealing layer 12, a gas barrier layer 14, and a heat seal layer 16 are sequentially formed on one side of the paper substrate 10. For example, when a vapor deposition layer is formed on the surface of a resin substrate and then laminated onto a paper substrate via an adhesive, the number of layers increases, resulting in a thicker laminate. However, compared to such a laminate, the laminate according to Embodiment 1 of the present invention can be made thinner.

[0135] In particular, in the manufacturing method of the laminate according to Embodiment 1 of the present invention, since the sealing layer 12 is formed by melt molding, a laminate with low oxygen permeability after bending and high gas barrier properties after bending can be obtained.

[0136] <Embodiment 2> In Embodiment 2 of the present invention, the same reference numerals are used for the same components and processes as in Embodiment 1, and their descriptions are omitted.

[0137] [Laminated structure] Referring to Figure 3, the laminate 1 of Embodiment 2 comprises a paper substrate 10, a sealing layer 12, and a gas barrier layer 14 in this order. The laminate 1 of Embodiment 2 has excellent gas barrier properties after bending. In the laminate 1 of Embodiment 2, as described later, the gas barrier layer 14 comprises an inorganic vapor deposition layer 145, preferably comprising an anchor coat layer 140 and an inorganic vapor deposition layer 145.

[0138] (1)Paper base material The paper substrate 10 in Embodiment 2 is the same as the paper substrate 10 in Embodiment 1.

[0139] (2) Sealing layer The sealing layer 12 of Embodiment 2 is the same as the sealing layer 12 of Embodiment 1, except for the following points.

[0140] In Embodiment 2, the sealing resin, as in Embodiment 1, contains the above-mentioned olefin-(meth)acrylic acid copolymer and / or the above-mentioned olefin-(meth)acrylic acid copolymer ionomer as essential components.

[0141] The basis weight of the sealing layer 12 is, for example, 1.5 g / m². 2 The above is preferable, preferably 3.0 g / m 2 The above is more preferable, or 5.0 g / m². 2 The above is preferable, and more preferably 7.5 g / m 2 That is all, and also, for example, 30.0 g / m 2 The following, preferably 20.0 g / m² 2 The following, and more preferably 15.0 g / m² 2 The following applies:

[0142] (3) Gas barrier layer The gas barrier layer 14 of Embodiment 2 includes an inorganic vapor deposition layer 145, preferably including an anchor coat layer 140 and an inorganic vapor deposition layer 145. When the gas barrier layer 14 includes an anchor coat layer 140 and an inorganic vapor deposition layer 145, the anchor coat layer 140 is located on one side of the sealing layer 12, preferably on one surface of the sealing layer 12, and the inorganic vapor deposition layer 145 is located on one side of the anchor coat layer 140, preferably on one surface of the anchor coat layer 140.

[0143] (Anchor coat layer) Preferably, the anchor coat layer 140 is formed between the sealing layer 12 and the inorganic vapor deposition layer 145 to improve adhesion between the sealing layer 12 and the inorganic vapor deposition layer 145. The anchor coat layer 140 is in contact with both the sealing layer 12 and the inorganic vapor deposition layer 145.

[0144] In this case, one side of the anchor coat layer 140 is in contact with the other side of the inorganic vapor deposition surface 145. One side of the sealing layer 12 is in contact with the other side of the anchor coat layer 140. If the heat seal layer 16 described later is formed, one side of the inorganic vapor deposition layer 145 is in contact with the other side of the heat seal layer 16.

[0145] Furthermore, if adhesion between the sealing layer 12 and the inorganic vapor deposition layer 145 can be ensured, the anchor coat layer 140 can be omitted.

[0146] The anchor coat layer 140 is formed by applying and drying the anchor coat material on the surface of the sealing layer 12. The anchor coat material includes an anchor coat resin.

[0147] Examples of anchor coating resins include polyurethane resins, acrylic resins, polyolefin resins, and polyvinyl alcohol resins, with polyurethane resins being preferred. Preferably, gas barrier polyurethane resins are used. Examples of gas barrier polyurethane resins include the gas barrier resin composition contained in the gas barrier coating material in Embodiment 1.

[0148] The basis weight of the anchor coat layer 140 is, for example, 0.2 g / m². 2 Preferably 0.5 g / m 2 Above all, a comfortable 1.0 g / m 2 That's all, and also, for example, 10g / m 2 Preferably 7.0 g / m 2 More preferably, 5.0 g / m 2 The following applies:

[0149] (Inorganic vapor deposited layer) Examples of inorganic materials (including metals) used in the inorganic vapor deposition layer 145 include magnesium, calcium, and barium from group 2 of the periodic table; titanium and zirconium from group 4; aluminum and indium from group 13; and silicon, germanium, and tin from group 14. Specifically, examples of inorganic materials include aluminum (Al), aluminum oxide (AlxOy), magnesium oxide (MgOx), titanium oxide (TiOx), indium oxide (InxOy), silicon oxide (SiOx), silicon oxide and nitride (SiOxNy), cerium oxide (CeOx), calcium oxide (CaOx), tin oxide (SnOx), diamond-like carbon film, or mixtures thereof. Among these, aluminum, silicon, and their oxides are preferred from the viewpoint of excellent gas barrier properties, and aluminum and its oxides are more preferred. Furthermore, the inorganic vapor deposition layer may be formed in multiple layers by combining multiple layers.

[0150] The thickness of the inorganic vapor deposition layer is, for example, 5 nm or more, preferably 20 nm or more, more preferably 50 nm or more, and also, for example, 250 nm or less, preferably 150 nm or less, more preferably 100 nm or less.

[0151] (4) Heat seal layer The heat seal layer 16 of Embodiment 2 is the same as the heat seal layer 16 of Embodiment 1.

[0152] [Method for manufacturing laminates] Referring to Figure 4, the manufacturing method of the laminate 1 of Embodiment 2 includes the steps of preparing a paper substrate 10 (Figure 4A), forming a sealing layer 12 on one side of the paper substrate 10 by melt molding (Figure 4B), forming a gas barrier layer 14 on one side of the sealing layer 12 (Figure 4C), and further including the step of forming a heat seal layer 16 on one side of the gas barrier layer 14. Furthermore, the manufacturing method of the laminate 1 of Embodiment 2 preferably includes the steps of preparing a paper substrate 10 (Figure 4A), forming a sealing layer 12 on one side of the paper substrate 10 by melt molding (Figure 4B), forming a gas barrier layer 14 on one side of the sealing layer 12 (Figure 4C), and further including the step of forming a heat seal layer 16 on one side of the gas barrier layer 14 (Figure 4D). The manufacturing method of the laminate of Embodiment 2 can produce a laminate 1 with excellent gas barrier properties after bending.

[0153] The process for preparing the paper substrate 10 shown in Figure 4A is the same as the process for preparing the paper substrate 10 shown in Figure 2A. Furthermore, the process for forming the sealing layer 12 shown in Figure 4B by melt molding is the same as the process for forming the sealing layer 12 by melt molding shown in Figure 2B.

[0154] (Process for forming a gas barrier layer) As shown in Figure 4C, an anchor coat layer 140 and an inorganic vapor deposition layer 145 are formed in this order as a gas barrier layer 14 on one side of the sealing layer 12. Preferably, an anchor coat layer 140 and an inorganic vapor deposition layer 145 are formed in this order as a gas barrier layer 14 on one side of the sealing layer 12.

[0155] In the process of forming the gas barrier layer 14, preferably, first, an anchor coat layer 140 is formed. The anchor coat layer 140 is formed by applying and drying the anchor coat material on one surface of the sealing layer 12. The application and drying conditions are the same as those for the application and drying of the gas barrier coating material described above.

[0156] Next, an inorganic vapor deposition layer 145 is formed on one surface of the anchor coat layer 140. To form the inorganic vapor deposition layer 145, the inorganic material described above is deposited. As a deposition method, vacuum deposition is one example. In vacuum deposition, as a heating method for the vacuum deposition apparatus, examples include electron beam heating, resistance heating, and induction heating. Resistance heating is preferred. As a condition for vacuum deposition, the vacuum level is, for example, 2.0 × 10⁻⁶. -3 Pa~10.0×10 -3 The pressure is Pa, and the heating conditions are, for example, 30A to 85A.

[0157] The process for forming the heat seal layer 16 shown in Figure 4D is the same as the process for forming the heat seal layer 16 shown in Figure 2D.

[0158] [Differentiation] The present invention includes, but is not limited to, the above-described embodiments 1 and 2. In embodiments 1 and 2, a sealing layer 12, a gas barrier layer 14, and a heat seal layer 16 are provided on one side of the paper substrate 10, but the sealing layer 12, gas barrier layer 14, and heat seal layer 16 can also be provided on both sides of the paper substrate 10, one side and the other side. In such a laminate 1, the heat seal layer 16, gas barrier layer 14, sealing layer 12, paper substrate 10, sealing layer 12, gas barrier layer 14, and heat seal layer 16 are provided in order toward one side.

[0159] Furthermore, while Embodiments 1 and 2 described above include a heat seal layer 16, the laminate of the present invention does not necessarily have to include a heat seal layer 16.

[0160] Alternatively, an overcoat layer can be formed on one side of the gas barrier layer 14, and a sheet seal layer 16 can be formed on one side of the overcoat layer. The overcoat layer is positioned between the gas barrier layer 14 and the sheet seal layer 16. The overcoat layer is formed by applying and drying a coating material similar to that used for the heat seal layer 16 to one side of the gas barrier layer 14. [Examples]

[0161] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified, "parts" and "%" are based on mass. Furthermore, specific numerical values ​​such as blending ratios (content), physical properties, and parameters used in the following description may be replaced with the corresponding upper limits (numerical values ​​defined as "less than or equal to" or "less than") or lower limits (numerical values ​​defined as "greater than or equal to" or "greater than") of the blending ratios (content), physical properties, and parameters described in the "Modes for Carrying Out the Invention" above.

[0162] [Preparing each ingredient] 1. Preparation of paper substrate As a paper base material, we use semi-glossy (bleached) kraft paper (product name: Nagoya Sarashi Ryuo, manufactured by Daio Paper Corporation, basis weight 70, 120, 140 g / m²). 2 ), unbleached paper (product name: Taio Atlas, manufactured by Daio Paper Corporation, basis weight 78 g / m²) 2 ) and cardboard (product name: AURA TNPL, basis weight 170, 200, 230 g / m²) 2 I prepared ).

[0163] 2. Preparation of sealing coating material (1) (Meth)acrylic resin composition (water-dispersible coating material) 50 parts by mass of ethylene-acrylic acid copolymer and 50 parts by mass of ethylene-isobutyl acrylate-methacrylic acid copolymer were melt-kneaded together to obtain a (meth)acrylic resin composition.

[0164] Furthermore, the proportion of constituent units derived from ethylene was 79.5% by mass of the total amount of the ethylene-acrylic acid copolymer, and the proportion of constituent units derived from acrylic acid was 20.5% by mass.

[0165] Furthermore, relative to the total amount of the ethylene-isobutyl acrylate-methacrylic acid copolymer, the content of constituent units derived from ethylene was 80.0% by mass, the content of constituent units derived from isobutyl acrylate was 10.0% by mass, and the content of constituent units derived from methacrylic acid was 10.0% by mass.

[0166] The above (meth)acrylic resin composition, 4.0 parts by mass of potassium hydroxide (neutralizing agent), and 140 parts by mass of deionized water were placed in a reaction vessel and stirred. The contents of the reaction vessel were heated to 150°C and maintained at that temperature for 4 hours. This neutralized the (meth)acrylic resin composition with potassium hydroxide (neutralizing agent). After that, the contents of the reaction vessel were cooled to room temperature (e.g., 25°C).

[0167] This yielded an aqueous dispersion of the neutralized (meth)acrylic resin composition. The solid content concentration of this aqueous dispersion was 42% by mass. The average particle size of this aqueous dispersion was 0.5 μm. This aqueous dispersion was used as an aqueous dispersion coating material.

[0168] (2) Inorganic filler-(meth)acrylic resin composition (water-dispersible coating material) Kaolin (Varisurf HX, manufactured by Imerys) was added to the aqueous dispersion of the neutralized (meth)acrylic resin composition obtained in (1) above, such that the solid content ratio (mass ratio) was (meth)acrylic resin composition:kaolin = 20:80, to obtain an aqueous dispersion of inorganic filler-(meth)acrylic resin composition. This aqueous dispersion was used as an aqueous dispersion coating material.

[0169] (3) Ethylene-(meth)acrylic acid copolymer (molten coating material) By copolymerizing ethylene with methacrylic acid, the following polymers A, B, and C were prepared as ethylene-(meth)acrylic acid copolymers.

[0170] Furthermore, the acid content (the proportion of polymerization units derived from (meth)acrylic acid) of each olefin-(meth)acrylic acid copolymer was calculated using the following method. Specifically, the acid content was calculated as the proportion of (meth)acrylic acid relative to the total amount of olefin and (meth)acrylic acid in the raw materials of the olefin-(meth)acrylic acid copolymer.

[0171] Furthermore, the glass transition temperature of each olefin-(meth)acrylic acid copolymer was calculated using the following method. Specifically, the peak temperature of tanδ in the dynamic viscoelasticity measurement was calculated as the glass transition temperature (Tg).

[0172] Polymer A: Ethylene-(meth)acrylic acid copolymer, acid content 4.0% by mass, Tg -6℃

[0173] Polymer B: Ethylene-(meth)acrylic acid copolymer, acid content 11.0% by mass, Tg 26℃

[0174] Polymer C: Ethylene-(meth)acrylic acid copolymer, acid content 12.0% by mass, Tg 28℃

[0175] (4) Ethylene-(meth)acrylic acid copolymer ionomer (melt coating material) By copolymerizing ethylene with methacrylic acid and then neutralizing with metal ions, the following ethylene-(meth)acrylic acid copolymer ionomers, ionomer A, ionomer B, and ionomer C, were prepared.

[0176] Furthermore, the acid content (the proportion of polymerization units derived from (meth)acrylic acid) of each olefin-(meth)acrylic acid copolymer ionomer was calculated using the method described above.

[0177] Furthermore, the glass transition temperature of each olefin-(meth)acrylic acid copolymer ionomer was calculated using the method described above.

[0178] Ionomer A: Ethylene-(meth)acrylic acid copolymer ionomer, neutralized with sodium ions, Tg 57℃, MFR (190℃, 2.16kg load) 2.8g / 10min

[0179] Ionomer B: Ethylene-(meth)acrylic acid copolymer ionomer, neutralized with zinc ions, Tg 38℃, MFR (190℃, 2.16kg load) 5.0g / 10min

[0180] Ionomer C: Ethylene-(meth)acrylic acid copolymer ionomer, neutralized with zinc ions, Tg 42℃, MFR (190℃, 2.16kg load) 1.0g / 10min

[0181] 3. Preparation of gas barrier coating material (1) Preparation of gas barrier coating material (polyurethane resin) (i) Polyurethane dispersion The following components were mixed and reacted under a nitrogen atmosphere at 65-70°C until the isocyanate group concentration (NCO%) was 6.11% by mass or less. This yielded a clear isocyanate-terminated prepolymer reaction product. • 1,3-Xylylene diisocyanate (Takenate 500, 1,3-XDI, manufactured by Mitsui Chemicals): 143.2 parts by mass • Methylenebis(cyclohexyl isocyanate) (Vestanat H12MDI, H12MDI, manufactured by Evonik): 25.0 parts by mass · Ethylene glycol: 29.2 parts by mass Trimethylolpropane: 2.7 parts by mass Dimethylolpropionic acid: 14.8 parts by mass Methyl ethyl ketone (solvent): 121.6 parts by mass

[0182] Next, the reaction product was cooled to 40°C. Then, 11.0 parts by mass of triethylamine (TEA) was added to the reaction product. This neutralized the isocyanate-terminated prepolymer.

[0183] Next, a homodisperser was used to disperse the reaction product in 838.0 parts by mass of deionized water. Then, an aqueous amine solution was added to the resulting dispersion to carry out the chain extension reaction. The reaction product from the chain extension reaction was then aged for 1 hour. This yielded a gas barrier polyurethane resin. The aqueous amine solution was a mixture of 48.4 parts by mass of deionized water and 24.2 parts by mass of 2-((2-aminoethyl)amino)ethanol. Subsequently, an evaporator was used to remove methyl ethyl ketone and deionized water from the reaction product. This adjusted the solid content concentration to 30% by mass.

[0184] Based on the above, a polyurethane dispersion (PUD) was obtained in which a gas barrier polyurethane resin was dispersed in water. The pH of the obtained PUD was 8.6. The average particle size of the PUD was 58 nm.

[0185] (ii) Gas barrier resin composition 30.0 parts by mass of water, the NTS dispersion described below, and 0.7 parts by mass of 25% aqueous ammonia (thickening inhibitor) were mixed together and mixed in a mixer for 5 minutes. This yielded a dispersion of the additive.

[0186] NTS dispersion: A swellable, layered dispersion of inorganic compounds (product name: NTS-10NC, synthetic mica, manufactured by Topy Industries, Ltd., solid content concentration 10% by mass) 37.7 parts by mass

[0187] Next, a dispersion of the above-mentioned additives (49.0 parts by mass) and 51.0 parts by mass of PUD were mixed in a mixer for 5 minutes. This yielded a gas barrier resin composition containing a gas barrier polyurethane resin and a layered inorganic compound. In addition, a gas barrier coating material was obtained in which the PUD and additives were dispersed in water. The solid content concentration of the gas barrier coating material was 15% by mass.

[0188] 4. Preparation of heat-sealable coating material The above (1) (meth)acrylic resin composition (water-dispersible coating material) was used as a heat-sealable coating material.

[0189] 5. Fabrication of the laminate <Laminate of Embodiment 1> Laminates of Examples 1 to 24 and Comparative Examples 1 to 2 (laminated material of Embodiment 1) shown in Tables 1 to 3 were manufactured. In each example and comparative example, the composition (type of resin), formation method, and basis weight of each layer are as shown in Tables 1 to 3.

[0190] Note that "Total resin amount" in the table refers to 1 m of laminate. 2 The total mass (g) of resin contained in (g / m 2 In Embodiment 1, the resin is contained in the sealing layer, the gas barrier layer, and the heat seal layer, respectively.

[0191] (1) Preparation of paper substrate As paper substrates, we prepared paper substrates with different basis weights as described above. Furthermore, the surface of each paper substrate was subjected to corona treatment as described below.

[0192] (2) Formation of sealing layer (i) When the sealing resin is an ethylene-(meth)acrylic acid copolymer The sealing layer was formed as a melt-molded film. Specifically, an extrusion laminator with a 65 mmφ extruder (L / D=28) was used to extrude and coat a paper substrate with an ethylene-(meth)acrylic acid copolymer (melt coating material). More precisely, while the molten ethylene-(meth)acrylic acid copolymer film was extruded from the die of the extrusion laminator, the side of the film in contact with the paper substrate was treated with ozone, and then the molten film was laminated onto a paper surface that had been corona-treated in-line. The detailed conditions for the extrusion coating process were as follows.

[0193] Air gap: 120mm Machining speed: 120m / min Processing width: 500mm Ozone treatment: 25g / m² 3 , 1m 3 / h Corona treatment: 115W·min / m 2

[0194] Furthermore, when the sealing resin is polymer A as an ethylene-(meth)acrylic acid copolymer, the resin temperature under the die was set to 315°C. Also, when the sealing resin is polymer B or polymer C as an ethylene-(meth)acrylic acid copolymer, the resin temperature under the die was set to 290°C.

[0195] (ii) When the sealing resin is an ethylene-(meth)acrylic acid copolymer ionomer The sealing layer was formed as a melt-molded film. More specifically, the paper substrate was extruded and coated with an ethylene-(meth)acrylic acid copolymer ionomer (melt-coated material) in the same manner as in (i), except that the die-under resin temperature was set to 300°C.

[0196] (iii) When the sealing resin is a (meth)acrylic resin composition (aqueous dispersion) or an inorganic filler-(meth)acrylic resin composition (aqueous dispersion) The sealing layer was formed as a cast film. Specifically, an aqueous dispersion of a (meth)acrylic resin composition (water-dispersible coating material) or an inorganic filler-(meth)acrylic resin composition (water-dispersible coating material) was applied to one side of a paper substrate and dried at 120°C for 60 seconds.

[0197] (3) Formation of a gas barrier layer A gas barrier coating material was applied to one side of the sealing layer and dried at 120°C for 60 seconds.

[0198] (4) Formation of heat seal layer A heat-sealable coating material was applied to one side of the gas barrier layer and dried at 120°C for 60 seconds. The heat-seal layer was formed only on the laminates of Examples 9-10, Examples 17-24, and Comparative Examples 1-2.

[0199] <Laminate of Embodiment 2> Laminates of Examples 25-48 and Comparative Examples 3-4 (laminated structures of Embodiment 2) shown in Tables 4-6 were manufactured. In each example and comparative example, the composition (type of resin), formation method, and basis weight of each layer are as shown in Tables 4-6.

[0200] Note that "Total resin amount" in the table refers to 1 m of laminate. 2 The total mass (g) of resin contained in (g / m 2 In Embodiment 2, the resin is contained in the sealing layer, the anchor coat layer, and the heat seal layer, respectively.

[0201] Furthermore, the method for fabricating the laminate in Embodiment 2 is the same as the method for fabricating the laminate in Embodiment 1, except for the formation of the gas barrier layer, and therefore its description is omitted.

[0202] (Formation of a gas barrier layer) In forming the gas barrier layer, first, an anchor coat material containing anchor coat resin was applied to one side of the sealing layer and dried at 120°C for 60 seconds to form the anchor coat layer. As the anchor coat resin, a gas barrier coating material (polyurethane resin) containing the above-mentioned gas barrier polyurethane resin was used.

[0203] Next, the paper substrate (each sample) on which the anchor coat layer has been formed is placed in a vacuum deposition apparatus (ULVAC resistance heating type), and 1 × 10 -4 Under vacuum conditions of Pa, aluminum was deposited onto the surface of each anchor coat layer to form an inorganic vapor-deposited layer. The thickness of the inorganic vapor-deposited layer was 65 nm.

[0204] The heat seal layer was formed only on the laminates of Examples 33-34, Examples 41-48, and Comparative Examples 3-4.

[0205] 6. Evaluation of the laminate (1)Basic weight The weights of the sealing layer, anchor coat layer, gas barrier layer, and heat seal layer were measured using the following method. Specifically, before and after lamination of each layer, the laminate was left to stand for 24 hours at 23°C and 50% relative humidity, and the mass of the laminate was measured. The change in mass of the laminate before and after lamination of each layer was calculated as the mass (g) of each layer. Furthermore, the mass (g) of each layer was measured against the area (m²) of the laminate, which had been measured in advance.2 By dividing by ), the weighing capacity (g / m³) can be calculated. 2 The following was calculated. The results are shown in Tables 1-6.

[0206] (2) Paper conversion rate (%) The ratio of the mass of the paper substrate to the mass of the laminate (mass of paper substrate / mass of laminate) was calculated as the paper content ratio (%). The results are shown in Tables 1-6.

[0207] (3) Oxygen permeability (OTR) of the laminate (i) Before folding OTR Oxygen permeability of laminate (cc / m³) 2 The oxygen permeability (·day·atm) was measured using an oxygen permeability analyzer (MOCON, OX-TRAN 2 / 22H) at a temperature of 20°C and a relative humidity of 80%. The results are shown in Tables 1-6.

[0208] (ii) OTR after folding The laminate was folded twice in the following manner. In the first step, the laminate was folded at 2 kg / cm² so that the laminated side of each layer was folded inward (valley fold). 2 The laminate was bent at a 180° angle for 10 seconds under pressure. For the second time, the bending direction was changed by 90° from the first time so that a cross-shaped crease would be formed, and the laminate was again bent at 2 kg / cm² so that the stacked side of each layer was folded inward (valley fold). 2 The laminate was bent at a 180° angle for 10 seconds under pressure. The OTR of the bent laminate was measured in the same manner as in (i) above. The results are shown in Tables 1 to 6.

[0209] (4) Heat seal strength Two of each laminate were prepared. The heat-sealed layers of the two laminates were then brought into contact with each other, and they were subjected to a heating process of 140°C, 0.2 seconds, and 1 kg / cm². 2 The product was heat-sealed under the specified conditions. The heat seal strength (N / 15mm) was then measured using an Intesco tensile strength device (model number 201X). Based on the results, the following judgment was made.

[0210] A:3.0N / 15mm or more B: Above 1.5 N / 15 mm and less than 3.0 N / 15 mm C: Less than 1.5 N / 15 mm

[0211]

Table 1

[0212]

Table 2

[0213]

Table 3

[0214]

Table 4

[0215]

Table 5

[0216]

Table 6

[0217] In Tables 1 to 6, "-" indicates unmeasured.

[0218] 7. Discussion (1) Regarding the forming method In Comparative Examples 1 to 2 and Comparative Examples 3 to 4 (sealing layer 10 g / m 2 , heat-sealing layer 2.0 g / m 2 ), the sealing layer was formed as a cast film. In such a case, the gas barrier property of the laminate after bending was relatively low.

[0219] On the other hand, in Example 10, Example 18, Example 34, and Example 42 (sealing layer 10 g / m 2 , heat-sealing layer 2.0 g / m2 ) In this case, the blocking layer was formed as a melt-molded film. In such a case, the gas barrier property of the laminate after bending was relatively high.

[0220] (2) Regarding resin types In Examples 1, Example 3, and Example 7 (blocking layer 10 g / m 2 , heat-sealing layer 0.0 g / m 2 ), an ethylene-(meth)acrylic acid copolymer was used as the blocking resin. In such a case, the gas barrier property of the laminate after bending was relatively high.

[0221] On the other hand, in Examples 25, Example 27, and Example 31 (blocking layer 10 g / m 2 , heat-sealing layer 0.0 g / m 2 ), an ethylene-(meth)acrylic acid copolymer was used as the blocking resin. In such a case, the gas barrier property of the laminate after bending was relatively low.

[0222] (3) Regarding the acid content of the olefin-acrylic acid copolymer In Examples 1, Example 3, and Example 7 (blocking layer 10 g / m 2 , heat-sealing layer 0.0 g / m 2 ), ethylene-(meth)acrylic acid copolymers with different acid contents were used as the blocking resin, respectively.

[0223] Also, in Examples 25, Example 27, and Example 31 (blocking layer 10 g / m 2 , heat-sealing layer 0.0 g / m 2 ), ethylene-(meth)acrylic acid copolymers with different acid contents were used as the blocking resin, respectively.

[0224] Comparing these, when the acid content of the olefin-acrylic acid copolymer was 11% by mass or more, the gas barrier properties of the laminate after bending were relatively high. In particular, when the acid content of the olefin-acrylic acid copolymer was 12% by mass or more, the gas barrier properties of the laminate after bending were even higher.

[0225] On the other hand, when the acid content of the olefin-acrylic acid copolymer was less than 11% by mass, the gas barrier properties of the laminate after bending were relatively low.

[0226] (4) Glass transition temperature of olefin-acrylic acid copolymer Examples 1, 3, and 7 (sealing layer 10g / m²) 2 Heat seal layer 0.0 g / m 2 In those cases, ethylene-(meth)acrylic acid copolymers with different glass transition temperatures were used as sealing resins.

[0227] Also, Examples 25, 27, and 31 (sealing layer 10g / m²) 2 Heat seal layer 0.0 g / m 2 In those cases, ethylene-(meth)acrylic acid copolymers with different glass transition temperatures were used as sealing resins.

[0228] Comparing these, when the glass transition temperature of the olefin-acrylic acid copolymer was 10°C or higher, the gas barrier properties after bending the laminate were relatively high. In particular, when the glass transition temperature of the olefin-acrylic acid copolymer was 28°C or higher, the gas barrier properties after bending the laminate were even higher.

[0229] On the other hand, when the glass transition temperature of the olefin-acrylic acid copolymer was less than 10°C, the gas barrier properties of the laminate after bending were relatively low.

[0230] (5) Glass transition temperature of olefin-acrylic acid copolymer ionomers Example 12, Example 14, and Example 16 (sealing layer: 10 g / m 2 , heat-sealing layer: 0.0 g / m 2 ) ethylene-(meth)acrylic acid copolymer ionomers with different glass transition temperatures were used as the sealing resins, respectively.

[0231] Also, in Examples 35 - 36, Examples 37 - 38, and Examples 39 - 40 (sealing layer: 5 - 10 g / m 2 , heat-sealing layer: 0.0 g / m 2 ) ethylene-(meth)acrylic acid copolymer ionomers with different glass transition temperatures were used as the sealing resins, respectively.

[0232] When comparing these, when the glass transition temperature of the olefin-acrylic acid copolymer ionomer was 50°C or lower, the gas barrier property of the laminate after bending was relatively high. Especially when the glass transition temperature of the olefin-acrylic acid copolymer was 40°C or lower, the gas barrier property of the laminate after bending was even higher.

[0233] On the other hand, when the glass transition temperature of the olefin-acrylic acid copolymer ionomer exceeded 50°C, the gas barrier property of the laminate after bending was relatively low.

[0234] (6) Regarding the basis weight of the paper substrate In Examples 19 - 24 and Examples 43 - 47 (sealing layer: 10 g / m 2 , heat-sealing layer: 2.0 g / m 2 ) papers with different basis weights were used as the paper substrates, respectively.

[0235] When comparing these, when the basis weight of the paper substrate was 150 g / m 2 or more, the gas barrier property of the laminate after bending was relatively high. Especially when the basis weight of the paper substrate was 180 g / m 2 or less, the gas barrier property of the laminate after bending was even higher.

[0236] On the other hand, the basis weight of the paper substrate is 150 g / m². 2 When the value was less than [value], the gas barrier properties of the laminate after bending were relatively low.

[0237] Furthermore, the basis weight of the paper substrate is 180 g / m². 2 The heat seal strength of the laminate was relatively high under the following conditions: In particular, the basis weight of the paper substrate was 100 g / m². 2 The heat seal strength of the laminate was even higher under the following conditions:

[0238] On the other hand, the basis weight of the paper substrate is 180 g / m². 2 When this value was exceeded, the heat seal strength of the laminate was relatively low.

[0239] (7) Basis weight of the laminate Examples 19-24 and Examples 43-47 (sealing layer 10g / m²) 2 Heat seal layer 2.0 g / m 2 In this case, different types of paper with varying basis weights were used as the paper base material. Therefore, each laminate had a different basis weight.

[0240] Comparing these, the basis weight of the laminate is 180 g / m². 2 In the above cases, the gas barrier properties of the laminate after bending were relatively high. In particular, when the basis weight of the laminate was 200 g / m² 2 In the above cases, the gas barrier properties of the laminate after bending were even higher.

[0241] On the other hand, the basis weight of the laminate is 180 g / m². 2 When the value was less than [value], the gas barrier properties of the laminate after bending were relatively low.

[0242] Furthermore, the basis weight of the laminate is 200 g / m². 2 The heat seal strength of the laminate was relatively high under the following conditions: In particular, when the basis weight of the laminate was 100 g / m². 2 The heat seal strength of the laminate was even higher under the following conditions:

[0243] On the other hand, the basis weight of the laminate is 200 g / m². 2 When this value was exceeded, the heat seal strength of the laminate was relatively low. [Explanation of symbols]

[0244] 1. Laminate 10 Paper base material 12. Sealing layer 14. Gas barrier layer 16 Heat seal layer 140 Anchor Coat Layer 145 Inorganic vapor deposition layer

Claims

1. The process of preparing the paper substrate, A step of forming a sealing layer on at least one side of the aforementioned paper substrate by melt molding, The process includes forming a gas barrier layer on one side of the sealing layer, The sealing layer contains a sealing resin, A method for producing a laminate, wherein the sealing resin contains an olefin-(meth)acrylic acid copolymer and / or an olefin-(meth)acrylic acid copolymer ionomer.

2. The method for producing a laminate according to claim 1, wherein the sealing resin contains an olefin-(meth)acrylic acid copolymer.

3. The basis weight of the aforementioned paper substrate is 180 g / m². ２ The method for manufacturing a laminate according to claim 1 or 2, which is as follows:

4. The basis weight of the laminate is 200 g / m². ２ The method for manufacturing a laminate according to claim 1 or 2, which is as follows:

5. The method for producing a laminate according to claim 1 or 2, wherein the gas barrier layer contains a gas barrier resin composition.

6. The method for manufacturing a laminate according to claim 1 or 2, wherein the gas barrier layer comprises an inorganic vapor deposition layer.

7. Furthermore, the method for manufacturing a laminate according to claim 1 or 2, further comprising the step of forming a heat seal layer on one side of the gas barrier layer.

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