Barrier substrates, barrier laminates, and packaging containers

Abstract

The present invention provides a barrier substrate having a gas barrier layer formed on a stretched polypropylene substrate, which exhibits an excellent balance between gas barrier properties and slipperiness. [Solution] A barrier substrate comprising a polypropylene substrate having a first surface layer and a second surface layer, and a gas barrier layer provided on the first surface layer, wherein the polypropylene substrate is a stretched substrate, the first surface layer contains first particles, the average particle diameter of the first particles is 0.5 μm or more and 3.5 μm or less, and the content of the first particles in the first surface layer is 50 ppm or more and 1,800 ppm or less, based on the mass of the first surface layer.

Description

[Technical Field]

[0001] This disclosure relates to barrier substrates, barrier laminates, and packaging containers. [Background technology]

[0002] Polyester substrates, such as polyethylene terephthalate (hereinafter also referred to as "polyester substrates"), have excellent mechanical properties, chemical stability, heat resistance, and transparency, and are also inexpensive. For this reason, polyester substrates have conventionally been used as substrates for laminations used in the manufacture of packaging containers.

[0003] Depending on the contents filled in the packaging container, the packaging container may require gas barrier properties such as oxygen barrier and water vapor barrier properties. To meet this requirement, a vapor-deposited film containing alumina or silica is formed on the surface of the polyester substrate (see, for example, Patent Document 1). In recent years, alternative substrates to polyester substrates have been sought, and for example, the use of polyolefin substrates, particularly polypropylene substrates, is being considered. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2005-053223 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The Disclosers investigated the use of a stretched polypropylene substrate (hereinafter also referred to as "stretched polypropylene substrate") instead of a conventional polyester substrate. As a result of their investigation, the Disclosers found that when a barrier substrate is manufactured by forming a gas barrier layer including a vapor-deposited film, etc., on a stretched polypropylene substrate, the balance between gas barrier properties and slipperiness may not be sufficient.

[0006] One of the problems addressed by this disclosure is to provide a barrier substrate having a gas barrier layer formed on a stretched polypropylene substrate, which exhibits an excellent balance between gas barrier properties and slipperiness. [Means for solving the problem]

[0007] The barrier substrate of this disclosure comprises a polypropylene substrate having a first surface layer and a second surface layer, and a gas barrier layer provided on the first surface layer, wherein the polypropylene substrate is a stretched substrate, the first surface layer contains first particles, the average particle diameter of the first particles is 0.5 μm or more and 3.5 μm or less, and the content of the first particles in the first surface layer is 50 ppm or more and 1,800 ppm or less, based on the mass of the first surface layer. [Effects of the Invention]

[0008] According to this disclosure, a barrier substrate is provided in which a gas barrier layer is formed on a stretched polypropylene substrate, and which has an excellent balance between gas barrier properties and slipperiness. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic cross-sectional view showing one embodiment of a barrier substrate. [Figure 2] Figure 2 is a schematic cross-sectional view showing one embodiment of a barrier substrate. [Figure 3] Figure 3 is a schematic cross-sectional view showing one embodiment of a vapor deposition apparatus. [Figure 4] Figure 4 is a schematic cross-sectional view showing one embodiment of a vapor deposition apparatus. [Figure 5] Figure 5 is a schematic cross-sectional view showing another embodiment of the vapor deposition apparatus. [Figure 6] Figure 6 is a schematic cross-sectional view showing one embodiment of a barrier laminate. [Figure 7] Figure 7 is a schematic cross-sectional view showing one embodiment of a barrier laminate. [Figure 8] Figure 8 is a schematic cross-sectional view showing one embodiment of a barrier laminate. [Figure 9] FIG. 9 is a front view showing an embodiment of the packaging container. [Figure 10] FIG. 10 is a perspective view showing an embodiment of the packaging container.

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described in detail. The present disclosure can be implemented in many different forms and is not construed as being limited to the description of the embodiments exemplified below. The drawings may schematically represent the width, thickness, shape, etc. of each layer compared to the embodiments for the sake of clearer explanation, but this is merely an example and does not limit the interpretation of the present disclosure. In this specification and each figure, elements that are the same as those already described with respect to the previously shown figures may be denoted by the same reference numerals, and detailed description may be omitted as appropriate.

[0011] In the following description, each component that appears (for example, polypropylene, α-olefin, resin material, additive, particle, and inorganic oxide, and other components) may be used alone or in combination of two or more.

[0012] [Barrier Substrate] The barrier substrate of the present disclosure includes a polypropylene substrate having a first surface layer and a second surface layer, and a gas barrier layer provided on the first surface layer. In one embodiment, the gas barrier layer has a vapor deposition film composed of an inorganic oxide. In one embodiment, the gas barrier layer further includes a barrier coating layer on the surface opposite to the surface on the polypropylene substrate side in the vapor deposition film. In one embodiment, the barrier substrate of the present disclosure may further include an anchor coating layer between the polypropylene substrate and the vapor deposition film.

[0013] The barrier substrate 1 shown in Figure 1 comprises a polypropylene substrate 10, a vapor-deposited film 12, and a barrier coat layer 14 in this order in the thickness direction. The polypropylene substrate 10 has a first surface layer 10a and a second surface layer 10b facing the first surface layer 10a. The vapor-deposited film 12 is provided on the first surface layer 10a. The vapor-deposited film 12 and the barrier coat layer 14 constitute a gas barrier layer. The barrier substrate 1 shown in Figure 2 further comprises an anchor coat layer 11 between the polypropylene substrate 10 and the vapor-deposited film 12.

[0014] (Polypropylene base material) Polypropylene substrates are substrates that have undergone a stretching treatment. Hereafter, unless the stretching treatment is specifically mentioned, the term "polypropylene substrate" simply refers to a polypropylene substrate that has undergone a stretching treatment.

[0015] The polypropylene substrate is composed of at least polypropylene. By comprising the polypropylene substrate, the barrier substrate can, for example, improve the oil resistance of packaging containers made using the barrier substrate.

[0016] Polypropylene may be any of propylene homopolymer, propylene random copolymer, or propylene block copolymer, or a mixture of two or more selected from these.

[0017] A propylene homopolymer is a polymer consisting solely of propylene. A propylene random copolymer is a random copolymer of propylene and α-olefins other than propylene. A propylene block copolymer is a copolymer having polymer blocks made of propylene and polymer blocks made of at least α-olefins other than propylene. The latter polymer blocks may be polymer blocks made of propylene and α-olefins other than propylene.

[0018] Examples of α-olefins include α-olefins having 2 to 20 carbon atoms, specifically ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, and 6-methyl-1-heptene.

[0019] Among polypropylenes, random copolymers are preferable from the viewpoint of transparency. When rigidity and heat resistance of the packaging container are important, homopolymers are preferable. When impact resistance of the packaging container is important, block copolymers are preferable.

[0020] The melt flow rate (MFR) of polypropylene may, in one embodiment, be 0.1 g / 10 min to 50 g / 10 min or 0.3 g / 10 min to 30 g / 10 min, from the viewpoint of film-forming properties and processability. The MFR of polypropylene is measured in accordance with ASTM D1238, under conditions of a temperature of 230°C and a load of 2.16 kg.

[0021] As for the polypropylene, biomass-derived polypropylene or mechanically or chemically recycled polypropylene may be used.

[0022] The polypropylene content in the polypropylene substrate is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0023] The polypropylene substrate may contain resin materials other than polypropylene. Examples of resin materials include polyolefins such as polyethylene, (meth)acrylic resins, vinyl resins, cellulose resins, polyamides, polyesters, and ionomer resins.

[0024] Polypropylene substrates may contain additives. Examples of additives include crosslinking agents, antioxidants, antiblocking agents, lubricants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

[0025] Polypropylene substrates are substrates that have undergone stretching treatment. This can improve, for example, the heat resistance, impact resistance, water resistance, and dimensional stability of barrier substrates. Barrier laminates comprising such barrier substrates are suitable, for example, as packaging materials for packaging containers that undergo boiling or retorting treatment.

[0026] The stretching process may be uniaxial stretching or biaxial stretching. In one embodiment, the polypropylene substrate is a biaxially stretched polypropylene substrate.

[0027] When stretching in the longitudinal direction (the direction of substrate flow, MD direction), the stretching ratio is preferably 2 times or more and 15 times or less, more preferably 5 times or more and 13 times or less. When stretching in the transverse direction (the direction perpendicular to the MD direction, TD direction), the stretching ratio is preferably 2 times or more and 15 times or less, more preferably 5 times or more and 13 times or less. By setting the stretching ratio to 2 times or more, the strength and heat resistance of the polypropylene substrate can be further improved, and the printability of the polypropylene substrate can also be improved. From the viewpoint of the breaking limit of the polypropylene substrate, a stretching ratio of 15 times or less is preferable.

[0028] In this disclosure, the polypropylene substrate comprises a first surface layer and a second surface layer. The first surface layer is the surface layer on one side of the polypropylene substrate (the side on which a gas barrier layer such as a vapor-deposited film is formed), and the second surface layer is the surface layer on the other side of the polypropylene substrate.

[0029] In this disclosure, by setting the average particle size and content of particles in the first surface layer of the polypropylene substrate to specific ranges, for example, the slipperiness of the barrier substrate can be improved while maintaining its gas barrier properties. Higher slipperiness of the barrier substrate improves its processability. For example, it improves the lamination suitability of the barrier substrate, suppressing wrinkle formation and meandering of the substrate during line transport of the barrier substrate.

[0030] The first surface layer contains first particles. By containing particles in the first surface layer, for example, the slipperiness of the barrier substrate can be improved.

[0031] Examples of the first type of particle include inorganic compound-based antiblocking agents and resin particle-based antiblocking agents. Specific examples of inorganic compound-based antiblocking agents include oxides such as silica, aluminum oxide, magnesium oxide, calcium oxide, titanium oxide, and zinc oxide; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; carbonates such as magnesium carbonate and calcium carbonate; sulfates such as calcium sulfate and barium sulfate; silicates such as magnesium silicate, aluminum silicate, calcium silicate, and aluminosilicate; and others such as kaolin, talc, and diatomaceous earth. Specific examples of the resin particles include resin particles composed of resin components such as polymethyl methacrylate (PMMA), polystyrene, methyl methacrylate-styrene copolymer, polyester, polyamide, polytetrafluoroethylene, epoxy resin, urea resin, and phenolic resin. The resin particles may be crosslinked or non-crosslinked.

[0032] The average particle diameter of the first particles in the first surface layer is 0.5 μm or more and 3.5 μm or less, preferably 0.8 μm or more and 3.2 μm or less, more preferably 1.0 μm or more and 3.0 μm or less, and particularly preferably 1.3 μm or more and 2.7 μm or less. If the average particle diameter exceeds 3.5 μm, the uniformity of the gas barrier layer formed on the first surface layer decreases, and the gas barrier properties (especially oxygen barrier properties) may not be fully exhibited. When the average particle diameter is within the above range, for example, it tends to be possible to improve the slipperiness while maintaining the gas barrier properties of the barrier substrate.

[0033] In this disclosure, the average particle diameter refers to the average particle diameter (arithmetic mean diameter) measured for 100 randomly selected non-aggregated particles by observing the cross-section in the thickness direction of each layer with a scanning electron microscope (SEM).

[0034] The content of the first particles in the first surface layer is 50 ppm to 1,800 ppm, preferably 100 ppm to 1,500 ppm, and more preferably 150 ppm to 1,000 ppm, based on the mass of the first surface layer. If the content exceeds 1,800 ppm, the uniformity of the gas barrier layer formed on the first surface layer decreases, and the gas barrier properties (especially oxygen barrier properties) may not be fully exhibited. When the content is within the above range, for example, it tends to be possible to improve the slipperiness while maintaining the gas barrier properties of the barrier substrate.

[0035] In one embodiment, the first surface layer contains polypropylene. The polypropylene content in the first surface layer is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more. The upper limit of the polypropylene content is defined, for example, by the content of the first particles.

[0036] The thickness of the first surface layer is preferably 0.3 μm to 5 μm, more preferably 0.4 μm to 3 μm, and even more preferably 0.5 μm to 2 μm. The thickness of each layer can be measured by observing the cross-section of the substrate with a scanning electron microscope (SEM). If a layer has protrusions caused by particles, it is preferable to measure the thickness of each layer in a region where no such protrusions are formed.

[0037] The ratio of the average particle diameter of the first particles in the first surface layer to the thickness of the first surface layer (average particle diameter / thickness) is preferably 0.3 or more and 5.0 or less, more preferably 0.8 or more and 4.0 or less, and even more preferably 1.0 or more and 3.0 or less.

[0038] In one embodiment, the second surface layer contains second particles. By including particles in the second surface layer, for example, the slipperiness of the barrier substrate can be further improved.

[0039] Examples of the second type of particle include inorganic compound-based antiblocking agents and resin particle-based antiblocking agents. Specific examples of inorganic compound-based antiblocking agents include oxides such as silica, aluminum oxide, magnesium oxide, calcium oxide, titanium oxide, and zinc oxide; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; carbonates such as magnesium carbonate and calcium carbonate; sulfates such as calcium sulfate and barium sulfate; silicates such as magnesium silicate, aluminum silicate, calcium silicate, and aluminosilicate; and others such as kaolin, talc, and diatomaceous earth. Specific examples of the resin particles include resin particles composed of resin components such as polymethyl methacrylate (PMMA), polystyrene, methyl methacrylate-styrene copolymer, polyester, polyamide, polytetrafluoroethylene, epoxy resin, urea resin, and phenolic resin. The resin particles may be crosslinked or non-crosslinked.

[0040] The average particle size of the second particles in the second surface layer is preferably 1.0 μm or more and 10 μm or less, more preferably 1.5 μm or more and 8.0 μm or less, even more preferably 2.0 μm or more and 7.0 μm or less, and particularly preferably more than 3.5 μm and 6.0 μm or less. This can further improve the slipperiness of the barrier substrate, for example.

[0041] Preferably, the average particle diameter of the first particles in the first surface layer is smaller than the average particle diameter of the second particles in the second surface layer. This allows, for example, the surface of the first surface layer to be smoother than that of the second surface layer, and therefore the ability to form a gas barrier layer such as a vapor-deposited film can be improved.

[0042] The content of the second particles in the second surface layer is preferably 500 ppm to 4,000 ppm, more preferably 1,000 ppm to 3,000 ppm, and even more preferably 1,300 ppm to 2,500 ppm, based on the mass of the second surface layer. This can further improve the slipperiness of the barrier substrate, for example. Furthermore, by including particles in the second surface layer, peeling charge can be suppressed, and therefore the generation of static electricity can also be suppressed.

[0043] Preferably, the content of the first particles in the first surface layer is smaller than the content of the second particles in the second surface layer. This allows for further improvement of the balance between the gas barrier properties and slipperiness of the barrier substrate, for example.

[0044] In one embodiment, the second surface layer contains polypropylene. The polypropylene content in the second surface layer is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more. The upper limit of the polypropylene content is defined, for example, by the content of the second particles.

[0045] The thickness of the second surface layer is preferably 0.3 μm to 5 μm, more preferably 0.4 μm to 3 μm, and even more preferably 0.5 μm to 2 μm.

[0046] The ratio of the average particle diameter of the second particles in the second surface layer to the thickness of the second surface layer (average particle diameter / thickness) is preferably 0.5 or more and 8.0 or less, more preferably 2.0 or more and 7.0 or less, and even more preferably 3.5 or more and 6.0 or less.

[0047] The polypropylene substrate may have an intermediate layer between the first surface layer and the second surface layer. The intermediate layer is made of polypropylene. The intermediate layer may have a single-layer structure or a multi-layer structure. The intermediate layer does not need to contain particles such as antiblocking agents.

[0048] The polypropylene content in the intermediate layer is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0049] The thickness of the polypropylene substrate is preferably 10 μm to 100 μm, more preferably 10 μm to 50 μm, and even more preferably 15 μm to 25 μm. If the thickness is above the lower limit, for example, the strength and heat resistance of the barrier substrate can be further improved. If the thickness is below the upper limit, for example, the processability of the barrier substrate can be further improved.

[0050] In one embodiment, the polypropylene substrate is a co-extruded stretched film. The polypropylene substrate can be produced, for example, by forming a laminated film using a T-die method or an inflation method, etc., with a resin composition containing polypropylene and first particles, a resin composition containing polypropylene or polypropylene, and a resin composition containing polypropylene and second particles, and then stretching the laminated film. The stretching of the laminated film may be performed simultaneously with the film formation using the inflation method.

[0051] In one embodiment, the polypropylene substrate may be surface-treated. This can improve, for example, the adhesion between the polypropylene substrate and other layers. Examples of surface treatment methods include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment; and chemical treatments such as oxidation treatment using chemicals. An easy-adhesion layer may be provided on the surface of the polypropylene substrate.

[0052] The barrier substrate may have a printed layer on a second surface layer of a polypropylene substrate. The image formed on the printed layer is not particularly limited and may include letters, patterns, symbols, and combinations thereof. The printed layer can also be formed using biomass-derived ink. This further reduces the environmental impact.

[0053] Conventional printing methods such as gravure printing, offset printing, and flexographic printing can be used to form the printed layer. Among these, flexographic printing is preferred from the viewpoint of reducing environmental impact.

[0054] (Anchor coat layer) In one embodiment, the barrier substrate of this disclosure includes an anchor coat layer between a polypropylene substrate and a gas barrier layer (particularly an inorganic oxide vapor-deposited film). This increases the adhesion strength between the polypropylene substrate and the inorganic oxide vapor-deposited film, and also provides an inorganic oxide vapor-deposited film consisting of a dense, gapless, and highly flexible continuous layer. Furthermore, by providing the anchor coat layer on the first surface layer of the polypropylene substrate, the surface of the substrate can be made smoother. This, for example, can further improve the gas barrier properties.

[0055] Therefore, high gas barrier properties can be obtained, and the rupture of the inorganic oxide vapor-deposited film and barrier coat layer due to deformation or bending of the film, as well as the resulting decrease in gas barrier properties, can be suppressed. By providing an anchor coat layer, a barrier substrate with excellent heat resistance and oil resistance that can withstand boiling and retort sterilization treatments can be obtained.

[0056] In one embodiment, the anchor coating agent for forming the anchor coating layer contains a functional group-containing (meth)acrylic resin, an isocyanate compound as a curing agent, and a silane coupling agent.

[0057] Examples of functional group-containing (meth)acrylic resins include hydroxyl group-containing (meth)acrylic resins, carboxyl group-containing (meth)acrylic resins, epoxy group-containing (meth)acrylic resins, and amino group-containing (meth)acrylic resins. Among these, hydroxyl group-containing (meth)acrylic resins are particularly preferred because the reaction rate can be easily controlled.

[0058] In one embodiment, the hydroxyl group-containing (meth)acrylic resin is produced from a neutral monomer and a hydroxyl group-containing (meth)acrylic monomer.

[0059] Examples of neutral monomers include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-hexyl (meth)acrylate, lauryl (meth)acrylate, styrene, vinyltoluene, and vinyl acetate.

[0060] Examples of hydroxyl group-containing (meth)acrylic monomers include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate.

[0061] Functional group-containing (meth)acrylic resins other than hydroxyl group-containing (meth)acrylic resins can, in one embodiment, be produced from the above-mentioned neutral monomer and a carboxyl group-containing monomer such as (meth)acrylic acid, maleic acid, and itaconic acid; an epoxy group-containing monomer such as glycidyl (meth)acrylate; or a nitrogen-containing monomer such as (meth)acrylamide, N-methylol(meth)acrylamide, diacetone(meth)acrylamide, and dimethylaminoethyl (meth)acrylate.

[0062] The following explanation primarily describes the case where hydroxyl group-containing (meth)acrylic resin is used. The glass transition temperature (Tg) of the hydroxyl group-containing (meth)acrylic resin is preferably 50°C to 200°C, more preferably 70°C to 150°C. A Tg of 50°C or higher suppresses, for example, blocking. A Tg of 200°C or lower provides, for example, excellent curability. Tg is obtained by differential scanning calorimetry (DSC) in accordance with JIS K7121.

[0063] The number-average molecular weight of the hydroxyl group-containing (meth)acrylic resin is preferably 10,000 or more and 100,000 or less. A number-average molecular weight of 10,000 or more can suppress blocking, for example. A number-average molecular weight of 100,000 or less provides excellent coating properties, for example. The number-average molecular weight is measured by gel permeation chromatography (GPC) in accordance with JIS K7252-1 (2008) and is expressed as a standard polystyrene equivalent.

[0064] The hydroxyl value of the hydroxyl-containing (meth)acrylic resin is preferably 20 mg KOH / g or more and 200 mg KOH / g or less, more preferably 30 mg KOH / g or more and 150 mg KOH / g or less. When the hydroxyl value is 20 mg KOH / g or more, for example, excellent interlayer adhesion and improved gas barrier properties can be achieved. The hydroxyl value is measured in accordance with JIS K0070.

[0065] The isocyanate compound used as a curing agent is any compound known as an isocyanate curing agent that reacts with a hydroxyl group-containing (meth)acrylic resin to form a urethane bond. Examples include aromatic diisocyanate monomers such as tolylene diisocyanate, xylylene diisocyanate, and 4,4-diphenylmethane diisocyanate; aliphatic diisocyanate monomers such as hexamethylene diisocyanate; and polymers or derivatives thereof.

[0066] Silane coupling agents are organosilicon compounds that contain both a hydrolysis group that reacts with inorganic substances and an organic functional group that reacts with organic substances within a single molecule. Examples of hydrolysis groups that react with inorganic substances include alkoxy groups such as methoxy and ethoxy groups, acetoxy groups, and chloro groups. Preferred organic functional groups that react with organic substances are functional groups that react with hydroxyl groups in hydroxyl group-containing (meth)acrylic resins or isocyanate groups in isocyanate compounds. Examples include isocyanate groups, amino groups, epoxy groups, and mercapto groups, and may also be vinyl groups and methacrylate groups.

[0067] The organosilicon compounds described above may have alkyl or phenyl groups that do not react with either inorganic or organic substances. The organosilicon compounds may be mixed with silicon compounds that do not have organic functional groups, such as alkoxysilanes that have only hydrolysis groups.

[0068] Examples of silane coupling agents include amino group-containing silane coupling agents such as N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and N-phenyl-3-aminopropyltrimethoxysilane; epoxy group-containing silane coupling agents such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane; mercapto group-containing silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane; and isocyanate group-containing silane coupling agents such as 3-isocyanatetopropyltriethoxysilane and 3-isocyanatetopropyltrimethoxysilane.

[0069] Any solvent can be used to dissolve the hydroxyl group-containing (meth)acrylic resin, as long as it maintains the fluidity of the anchor coating agent during application and provides a smooth anchor coating layer. Examples of such solvents include alcohol-based solvents such as methanol, ethanol, isopropyl alcohol, n-butyl alcohol, and isobutyl alcohol; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as ethyl acetate, n-propyl acetate, n-butyl acetate, and isobutyl acetate; glycol-based solvents such as 2-butoxyethanol and propylene glycol monomethyl ether; and hydrocarbon-based solvents such as toluene, xylene, n-hexane, and methylcyclohexane.

[0070] In anchor coating agents, the molar ratio of isocyanate groups in the isocyanate compound to hydroxyl groups in the hydroxyl group-containing (meth)acrylic resin is preferably 0.3 to 3.0. This improves, for example, curability and blocking resistance.

[0071] The content of the silane coupling agent in the anchor coating agent is preferably 3 to 80 parts by mass per 100 parts by mass of the solid content of the hydroxyl group-containing (meth)acrylic resin. This improves, for example, interlayer adhesion and blocking resistance.

[0072] For example, an anchor coating agent is prepared by mixing a hydroxyl group-containing (meth)acrylic resin, an isocyanate compound, and a silane coupling agent in any desired ratio, and this is coated onto a polypropylene substrate to form an anchor coating layer. The anchor coating agent can be prepared, for example, by mixing a silane coupling agent and a hydroxyl group-containing (meth)acrylic resin, adding a solvent to dilute it to any desired concentration, and then mixing it with an isocyanate compound. Alternatively, the silane coupling agent can be mixed in a solvent beforehand, and then the hydroxyl group-containing (meth)acrylic resin and isocyanate compound can be mixed in any desired order.

[0073] The anchor coat layer can be formed by coating with an anchor coat agent using a known coating method such as roll coating, gravure coating, knife coating, dip coating, and spray coating, drying and removing the solvent or diluent, and then curing it.

[0074] The thickness of the anchor coat layer is preferably 0.02 μm to 5 μm, more preferably 0.05 μm to 3 μm, even more preferably 0.1 μm to 1 μm, and even more preferably 0.1 μm to 0.5 μm. If the thickness is above the lower limit, for example, the adhesion of the vapor-deposited film can be further improved, the gas barrier properties can be further improved, and the laminate strength of the packaging container can be further improved. If the thickness is below the upper limit, for example, the processability of the substrate and the recyclability of the packaging container can be further improved.

[0075] (Vaporized film) In one embodiment, the barrier substrate of this disclosure comprises a vapor-deposited film composed of an inorganic oxide as a gas barrier layer. In one embodiment, the barrier substrate comprises a vapor-deposited film on an anchor coat layer. This improves the gas barrier properties of the barrier substrate, specifically the oxygen barrier properties and water vapor barrier properties. A packaging container made using the barrier substrate can suppress the mass reduction of the contents filled inside the packaging container.

[0076] Examples of inorganic oxides include aluminum oxide (alumina), silicon oxide (silica), magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, barium oxide, and silicon carbide oxide (carbon-containing silicon oxide). Among these, silica, silicon carbide oxide, and alumina are preferred, with silicon carbide oxide being more preferred.

[0077] In one embodiment, silica is more preferable as the inorganic oxide because aging treatment after vapor deposition film formation is not required. In another embodiment, carbon-containing silicon oxide is more preferable as the inorganic oxide because the decrease in gas barrier properties can be suppressed even when the barrier laminate is bent.

[0078] The thickness of the vapor-deposited film is preferably 1 nm to 150 nm, more preferably 5 nm to 60 nm, and even more preferably 10 nm to 40 nm. If the thickness is above the lower limit, for example, the oxygen barrier and water vapor barrier properties of the barrier substrate can be further improved. If the thickness is below the upper limit, for example, the occurrence of cracks in the vapor-deposited film can be suppressed, and the recyclability of the packaging container can be improved.

[0079] It is preferable that the surface of the deposited film is subjected to the above-mentioned surface treatment. This improves the adhesion between the deposited film and the adjacent layer.

[0080] Examples of methods for forming deposited films include physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, and ion plating, as well as chemical vapor deposition (CVD) methods such as plasma chemical vapor deposition, thermochemical vapor deposition, and photochemical vapor deposition.

[0081] The deposited film may be a single layer formed by a single deposition process, or a multilayer formed by multiple deposition processes. If the deposited film is multilayer, each layer may be composed of the same inorganic oxide, or of different inorganic oxides. Each layer may be formed by the same method, or by different methods.

[0082] A vacuum deposition apparatus with plasma assistance can be used as the apparatus for forming a vapor-deposited film by the PVD method. One embodiment of a method for forming a vapor-deposited film using a vacuum deposition apparatus with plasma assistance is described below.

[0083] In one embodiment, the vacuum deposition apparatus, as shown in Figures 3 and 4, comprises a vacuum vessel A, an unwinding section B, a deposition drum C, a winding section D, a transport roll E, an evaporation source F, a reaction gas supply section G, an anti-deposition box H, a deposition material I, and a plasma gun J. Figure 3 is a schematic cross-sectional view of the vacuum deposition apparatus in the XZ plane. Figure 4 is a schematic cross-sectional view of the vacuum deposition apparatus in the XY plane.

[0084] As shown in Figure 3, the substrate S wound onto the film-forming drum C is positioned at the top of the vacuum vessel A with the surface intended for deposition facing downwards. Below the film-forming drum C in the vacuum vessel A, an electrically grounded protective box H is positioned. An evaporation source F is positioned on the bottom surface of the protective box H. The film-forming drum C is positioned in the vacuum vessel A such that the substrate S wound onto the film-forming drum C is positioned opposite the top surface of the evaporation source F at a certain distance. Conveyor rolls E are positioned between the unwinding section B and the film-forming drum C, and between the film-forming drum C and the winding section D. The vacuum vessel A is connected to a vacuum pump (not shown). The evaporation source F holds the deposition material I and is equipped with a heating device (not shown). The reaction gas supply section G is the part that supplies reaction gases (oxygen, nitrogen, helium, argon, and mixtures thereof, etc.) that react with the evaporated deposition material I.

[0085] The evaporated deposition material I, heated by the evaporation source F, is irradiated onto the substrate S. Simultaneously, plasma is also irradiated onto the substrate S from the plasma gun J, forming a deposited film on the substrate S. Details of the above film formation method are disclosed in Japanese Patent Publication No. 2011-214089.

[0086] Plasma generators used in plasma chemical vapor deposition (PVM) can include high-frequency plasma, pulsed-wave plasma, and microwave plasma generators. A device with two or more deposition chambers may also be used. Such a device preferably includes a vacuum pump and is capable of maintaining a vacuum in each deposition chamber. The vacuum level in each deposition chamber is 1 × 10 to 1 × 10 -6 Pa is preferable.

[0087] One embodiment of a method for depositing a vapor-deposited film using a plasma generator is described below. The substrate is sent to the deposition chamber and transported at a predetermined speed onto the surface of the cooling / electrode drum via auxiliary rolls. Next, a mixed gas composition containing a monomer gas for film formation containing inorganic oxides, oxygen gas, and an inert gas is supplied from the gas supply device into the deposition chamber. Plasma is generated on the substrate by glow discharge and irradiated to form a vapor-deposited film containing inorganic oxides on the substrate. Details of the above film formation method are disclosed in Japanese Patent Publication No. 2012-076292.

[0088] Figure 5 is a schematic diagram showing a plasma chemical vapor deposition apparatus used in the CVD method. In one embodiment, as shown in Figure 5, the plasma chemical vapor deposition apparatus unwinds a substrate S from an unwinding section B1 located inside a vacuum vessel A1 and transports the substrate S onto the surface of a cooling / electrode drum C1 at a predetermined speed via a transport roll E1. Oxygen, nitrogen, helium, argon, and mixed gases thereof are supplied from a reaction gas supply section G1, and film-forming monomer gases are supplied from a raw material gas supply section I1. While preparing a vapor deposition mixed gas composition consisting of these gases, the vapor deposition mixed gas composition is introduced into the vacuum vessel A1 through a raw material supply nozzle H1. Then, a plasma is generated on the substrate S transported onto the surface of the cooling / electrode drum C1 by a glow discharge plasma F1 and irradiated to form a vapor-deposited film on the substrate S. At this time, the cooling / electrode drum C1 is supplied with a predetermined power from a power supply K1 located outside the vacuum vessel A1, and a magnet J1 is placed near the cooling / electrode drum C1 to promote plasma generation. After the vapor-deposited film is formed, the substrate S is wound onto the winding section D1 via the transport roll E1 at a predetermined winding speed. In Figure 5, L1 represents the vacuum pump.

[0089] A continuous vapor deposition apparatus, equipped with a plasma pretreatment chamber and a deposition chamber, can be used as the apparatus for forming a vapor-deposited film. One embodiment of a method for forming a vapor-deposited film using such an apparatus is described below.

[0090] In the plasma pretreatment chamber, plasma is irradiated onto the substrate from a plasma supply nozzle. Next, in the film deposition chamber, a vapor-deposited film is formed on the plasma-treated substrate. Details of the above film deposition method are disclosed in International Publication No. 2019 / 087960.

[0091] The vapor-deposited film on the barrier substrate is preferably a vapor-deposited film formed by the CVD method, and more preferably a carbon-containing silicon oxide vapor-deposited film formed by the CVD method. This suppresses the decrease in gas barrier properties even when the barrier substrate is bent.

[0092] The carbon-containing silicon oxide vapor-deposited film contains silicon, oxygen, and carbon. In one embodiment of a carbon-containing silicon oxide vapor-deposited film, the carbon content C is preferably 3% to 50%, more preferably 5% to 40%, and even more preferably 10% to 35%, relative to 100% of the total of the three elements silicon, oxygen, and carbon. By setting the carbon content C within the above range, for example, a decrease in gas barrier properties can be suppressed even when the barrier substrate is bent. In this specification, the proportion of each element is on a molar basis.

[0093] In one embodiment of a carbon-containing silicon oxide vapor-deposited film, the silicon content (Si) is preferably 1% to 45%, more preferably 3% to 38%, and even more preferably 8% to 33%, relative to 100% of the total of the three elements silicon, oxygen, and carbon. The oxygen content (O) is preferably 10% to 70%, more preferably 20% to 65%, and even more preferably 25% to 60%, relative to 100% of the total of the three elements silicon, oxygen, and carbon. By setting the silicon content (Si) and oxygen content (O) within the above ranges, for example, the decrease in gas barrier properties can be further suppressed even when the barrier substrate is bent.

[0094] In one embodiment of a carbon-containing silicon oxide vapor-deposited film, the proportion of oxygen (O) is preferably higher than the proportion of carbon (C), and the proportion of silicon (Si) is preferably lower than the proportion of carbon (C). The proportion of oxygen (O) is preferably higher than the proportion of silicon (Si), meaning that the proportions are preferably decreasing in the order of O, C, and Si. This allows for a more suppression of the decrease in gas barrier properties, for example, even when the barrier substrate is bent.

[0095] The proportions of C, Si, and O in a carbon-containing silicon oxide vapor-deposited film can be measured by X-ray photoelectron spectroscopy (XPS) using narrow-scan analysis under the following measurement conditions.

[0096] (Measurement conditions) Equipment used: "ESCA-3400" (manufactured by Kratos) [1] Spectrum acquisition conditions Incident X-ray: MgKα (monochromatic X-ray, hν=1253.6eV) X-ray output: 150W (10kV 15mA) X-ray scanning area (measurement area): Approximately 6 mmφ Photoelectron capture angle: 90 degrees [2] Ion sputtering conditions Ionic species: Ar + Acceleration voltage: 0.2 (kV) Emission current: 20 (mA) Etching area: 10mmφ Ion sputtering was performed for 30 seconds, and the spectrum was collected.

[0097] (Barrier coat layer) In one embodiment, the barrier substrate may further comprise a barrier coating layer on the vapor-deposited film. That is, the barrier substrate may further comprise a barrier coating layer on the surface of the vapor-deposited film opposite to the surface facing the polypropylene substrate. This can improve, for example, the oxygen barrier properties and water vapor barrier properties of the barrier substrate. In this embodiment, the gas barrier layer comprises the vapor-deposited film and the barrier coating layer.

[0098] In one embodiment, the barrier coat layer contains a gas barrier resin. Examples of gas barrier resins include ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyacrylonitrile, polyester, polyamides such as nylon 6, nylon 6,6 and polymethoxyylene adipamide, polyurethane, and (meth)acrylic resins.

[0099] The gas barrier resin content in the barrier coat layer is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. With this configuration, for example, the gas barrier properties of the barrier coat layer can be improved. The barrier coat layer may contain the above-mentioned additives.

[0100] The thickness of the barrier coating layer containing the gas barrier resin is preferably 0.01 μm to 10 μm, more preferably 0.1 μm to 5 μm. By setting the thickness of the barrier coating layer to 0.01 μm or more, for example, the gas barrier properties can be further improved. By setting the thickness of the barrier coating layer to 10 μm or less, for example, the processability of the barrier laminate and the recyclability of the packaging container can be improved.

[0101] The barrier coating layer can be formed, for example, by applying and drying a coating solution obtained by dissolving or dispersing a material such as a gas barrier resin in water or a suitable organic solvent.

[0102] In another embodiment, the barrier coat layer is a gas barrier coating film formed by mixing a metal alkoxide, a water-soluble polymer, and optionally a silane coupling agent, and optionally adding water, an organic solvent, and a sol-gel catalyst, and then applying and drying the gas barrier composition on the vapor-deposited film. The gas barrier coating film contains hydrolyzed polycondensates obtained by hydrolysis and polycondensation of the above-mentioned metal alkoxide, etc., by the sol-gel method. By providing such a barrier coat layer on the vapor-deposited film, the occurrence of cracks in the vapor-deposited film can be effectively suppressed.

[0103] The metal alkoxide is represented by, for example, the formula (1). R 1 n M(OR 2 ) m (1) In the formula (1), R 1 and R 2 each independently represent an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n + m represents the valence of M.

[0104] R 1 and R 2 Examples of the organic group in include alkyl groups having 1 to 8 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, n-hexyl group and n-octyl group. The metal atom M is, for example, silicon, zirconium, titanium or aluminum.[[[]]aluminum.

[0105] Among the metal alkoxides, tetraalkoxylan is preferable. Examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane and tetrabutoxysilane.

[0106] Examples of the water-soluble polymer include hydroxyl group-containing polymers such as polyvinyl alcohol and ethylene-vinyl alcohol copolymer. Depending on the desired physical properties such as oxygen barrier property, water vapor barrier property, water resistance and weather resistance, either polyvinyl alcohol or ethylene-vinyl alcohol copolymer may be used, or both may be used in combination. Further, a gas barrier coating film obtained using polyvinyl alcohol and a gas barrier coating film obtained using ethylene-vinyl alcohol copolymer may be laminated. The usage amount of the water-soluble polymer is preferably 5 parts by mass or more and 500 parts by mass or less with respect to 100 parts by mass of the metal alkoxide.

[0107] The average degree of polymerization of the water-soluble polymer may be, for example, 500 to 5,000, or 1,000 to 4,000. The degree of saponification of the water-soluble polymer may be, for example, 80 mol% or more, 90 mol% or more, or 95 mol% or more. These physical properties can be measured in accordance with JIS K6726 in one embodiment.

[0108] The surface of the gas barrier coating film has a silicon atom to carbon atom ratio (Si / C), measured by X-ray photoelectron spectroscopy (XPS), which is preferably 1.60 or less, more preferably 0.50 to 1.60, and even more preferably 0.90 to 1.35. When the above ratio is below the upper limit, for example, the decrease in gas barrier properties can be suppressed even when the barrier substrate is bent. When the above ratio is above the lower limit, for example, when heating such as heat sealing is performed when manufacturing a packaging container using the barrier substrate, the decrease in gas barrier properties can be suppressed.

[0109] The above range of silicon-to-carbon atom ratios can be achieved by appropriately adjusting the amount of metal alkoxide used in the water-soluble polymer. In this specification, the silicon-to-carbon atom ratio is expressed on a molar basis.

[0110] The ratio of silicon atoms to carbon atoms can be measured by narrow-scan analysis under the following measurement conditions using X-ray photoelectron spectroscopy (XPS).

[0111] (Measurement conditions) Equipment used: "ESCA-3400" (manufactured by Kratos) [1] Spectrum acquisition conditions Incident X-ray: MgKα (monochromatic X-ray, hν=1253.6eV) X-ray output: 150W (10kV 15mA) X-ray scanning area (measurement area): Approximately 6 mmφ Photoelectron capture angle: 90 degrees [2] Ion sputtering conditions Ionic species: Ar + Acceleration voltage: 0.2 (kV) Emission current: 20 (mA) Etching area: 10mmφ Ion sputtering time: 30 seconds + 30 seconds + 60 seconds (total 120 seconds) A spectrum was collected.

[0112] As silane coupling agents, for example, known organic reactive group-containing organoalkoxysilanes can be used, and organoalkoxysilanes having epoxy or vinyl groups are preferred, such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and vinyltrimethoxysilane. The amount of silane coupling agent used is preferably 1 to 20 parts by mass per 100 parts by mass of metal alkoxide.

[0113] The gas barrier composition may contain water in a ratio of preferably 0.1 moles to 100 moles, more preferably 0.5 moles to 60 moles, per mole of metal alkoxide. By setting the water content above the lower limit, for example, the oxygen barrier and water vapor barrier properties of the barrier substrate can be improved. By setting the water content below the upper limit, for example, hydrolysis reactions can be carried out rapidly.

[0114] The gas barrier composition may contain an organic solvent. Examples of organic solvents include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and n-butyl alcohol.

[0115] Acids or amine compounds are preferred as catalysts for the sol-gel method. Examples of acids include mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid; and organic acids such as acetic acid and tartaric acid. The amount of acid used is preferably 0.001 moles or more and 0.05 moles or less per mole of the total molar amount of the metal alkoxide and the alkoxide portion (e.g., silicate portion) of the silane coupling agent.

[0116] Suitable amine compounds include tertiary amines that are substantially insoluble in water and soluble in organic solvents, such as N,N-dimethylbenzylamine, tripropylamine, tributylamine, and tripentylamine. The amount of amine compound used is preferably 0.01 parts by mass or more and 1.0 part by mass or less, and more preferably 0.03 parts by mass or more and 0.3 parts by mass or less, per 100 parts by mass of the total amount of the metal alkoxide and silane coupling agent.

[0117] Methods for applying the gas barrier composition include, for example, roll coating such as gravure roll coaters, spray coating, spin coating, dipping, brushing, bar coating, and application methods such as applicators.

[0118] The following describes one embodiment of a method for forming a gas barrier coating film. A gas barrier composition is prepared by mixing a metal alkoxide, a water-soluble polymer, a sol-gel catalyst, water, an organic solvent, and optionally a silane coupling agent. A polycondensation reaction gradually proceeds within the composition. The composition is applied to a vapor-deposited film by a conventional method and dried. This drying further promotes the polycondensation of the metal alkoxide and the water-soluble polymer (and the silane coupling agent if the composition contains one), forming a composite polymer layer. Multiple composite polymer layers may be laminated by repeating the above operation. For example, the applied composition is heated at a temperature preferably between 40°C and 150°C, more preferably between 60°C and 130°C, and even more preferably between 80°C and 120°C for 1 second to 10 minutes. This forms a gas barrier coating film.

[0119] The thickness of the gas barrier coating film is preferably 0.01 μm to 100 μm, more preferably 0.1 μm to 50 μm, and even more preferably 0.1 μm to 5 μm. This allows for improved gas barrier properties, suppression of crack formation in the vapor-deposited film, and improved recyclability of the packaging container.

[0120] [Barrier laminate] The barrier laminate of the present disclosure comprises a barrier substrate of the present disclosure and a sealant layer in this order in the thickness direction. In one embodiment, the barrier laminate of the present disclosure comprises a first substrate, a second substrate, and a sealant layer in this order in the thickness direction, wherein either the first substrate or the second substrate is the barrier substrate of the present disclosure, and the other of the first substrate or the second substrate is a stretched substrate made of polypropylene. Either the first substrate or the second substrate may be the barrier substrate of the present disclosure.

[0121] Figures 6 to 8 are schematic cross-sectional views showing one embodiment of a barrier laminate. The barrier laminate 2 shown in Figure 6 comprises a barrier substrate 1, an adhesive layer 20, and a sealant layer 30 in this order in the thickness direction. The barrier substrate 1 comprises a polypropylene substrate 10, a vapor-deposited film 12, and a barrier coat layer 14. In this example, the barrier coat layer 14 is in contact with the adhesive layer 20. The polypropylene substrate 10 has a first surface layer and a second surface layer, but these are omitted from Figures 6 to 8.

[0122] The barrier laminate 2 shown in Figure 7 comprises a stretched substrate 3 as the first substrate, an adhesive layer 20A, a barrier substrate 1 as the second substrate, an adhesive layer 20B, and a sealant layer 30, in this order in the thickness direction. In this example, the barrier coat layer 14 is in contact with the adhesive layer 20A, and the polypropylene substrate 10 is in contact with the adhesive layer 20B.

[0123] The barrier laminate 2 shown in Figure 8 comprises a barrier substrate 1 as a first substrate, an adhesive layer 20A, a stretched substrate 3 as a second substrate, an adhesive layer 20B, and a sealant layer 30, in this order in the thickness direction. In this example, the polypropylene substrate 10 constitutes the outermost layer of the barrier laminate 2, and the barrier coat layer 14 is in contact with the adhesive layer 20A. The barrier laminate 2 shown in Figures 6 to 8 may further include an anchor coat layer 11 between the polypropylene substrate 10 and the vapor-deposited film 12.

[0124] In one embodiment, the barrier laminate of this disclosure may further comprise a printed layer formed on a substrate such as a barrier substrate and a stretched substrate.

[0125] In one embodiment, the barrier laminate of the present disclosure comprises a stretched substrate made of polypropylene as the first substrate, and the barrier substrate of the present disclosure as the second substrate (see Figure 7). In this embodiment, the barrier laminate comprises a stretched substrate made of polypropylene, a barrier substrate, and a sealant layer in this order in the thickness direction. A barrier laminate with such a configuration exhibits appropriate protection of the vapor-deposited film when subjected to heat treatment or the like, and also shows high gas barrier properties.

[0126] In this disclosure, the phrase "AAA composed of polypropylene" means that the main component of the AAA is polypropylene, but the AAA is not limited to being composed solely of polypropylene. The AAA may contain other components besides polypropylene. Specifically, the polypropylene content in the AAA is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0127] <Sealant layer> The barrier laminate of this disclosure comprises a sealant layer. In one embodiment, the sealant layer contains a resin material that can be fused together by heat. Examples of resin materials that can be fused together by heat include polyolefins, specifically polyethylene such as low-density polyethylene, linear low-density polyethylene and medium-density polyethylene, polypropylene, polybutene, methylpentene polymer, and cyclic olefin copolymer.

[0128] Examples of resin materials that can fuse with each other by heat include ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylate copolymer, ethylene-(meth)acrylate ethyl copolymer, ethylene-vinyl alcohol copolymer, ionomer resin, acid-modified polyolefins obtained by modifying polyolefins with unsaturated carboxylic acids such as (meth)acrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid, polyesters such as polyethylene terephthalate, polyvinyl acetate, polyvinyl chloride, and (meth)acrylic resin.

[0129] In one embodiment, the sealant layer is made of polypropylene. In this embodiment, the sealant layer is made of the same type of resin material as the polypropylene substrate, i.e., polypropylene. This makes it possible to make the packaging container a monomaterial. After collecting used packaging containers, there is no need to separate the substrate and the sealant layer, which improves the recyclability of the packaging containers. By making the sealant layer of polypropylene, the oil resistance of the packaging container made using a barrier laminate can also be improved.

[0130] The polypropylene content in the sealant layer is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more. This can improve, for example, the recyclability of the packaging container.

[0131] When the sealant layer is made of polypropylene, the proportion of polypropylene to the total amount of resin material contained in the barrier laminate is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 88% by mass or more, and particularly preferably 90% by mass or more. This makes it possible to produce, for example, a monomaterial packaging container using the barrier laminate, thereby improving the recyclability of the packaging container.

[0132] Examples of polypropylene include propylene homopolymers, propylene random copolymers such as propylene-α-olefin random copolymers, and propylene block copolymers such as propylene-α-olefin block copolymers. Details of α-olefins are as described above. From the viewpoint of heat sealability, the density of polypropylene is, for example, 0.88 g / cm³. 3 More than 0.92g / cm 3 The following applies: Density is measured in accordance with JIS K7112, particularly Method D (density gradient tube method, 23°C). From the perspective of reducing environmental impact, biomass-derived polypropylene and / or recycled polypropylene may be used.

[0133] The sealant layer may contain additives. Examples of additives include crosslinking agents, antioxidants, antiblocking agents, lubricants, UV absorbers, light stabilizers, fillers, reinforcing agents, lubricants, antistatic agents, pigments, and modifying resins. For example, the sealant layer may contain an antistatic agent. This can suppress the generation of static electricity on the surface of the barrier laminate, and for example, can suppress adhesion between barrier laminates.

[0134] The sealant layer may have a single-layer structure or a multi-layer structure. The thickness of the sealant layer is preferably 10 μm to 200 μm, more preferably 20 μm to 150 μm. If the thickness is above the lower limit, for example, the lamination strength of the packaging container equipped with the barrier laminate can be further improved. If the thickness is below the upper limit, for example, the processability of the barrier laminate can be further improved. When making pouches (especially retort pouches) from the barrier laminate, the thickness of the sealant layer is even more preferably 30 μm to 100 μm.

[0135] The sealant layer is preferably an unstretched resin film, and more preferably an unstretched polypropylene film, from the viewpoint of heat sealability. The resin film can be manufactured, for example, by using a casting method, a T-die method, or an inflation method.

[0136] For example, an unstretched resin film corresponding to the sealant layer may be laminated onto a barrier substrate or a second substrate via an adhesive layer as needed, or the sealant layer may be formed by melt-extruding a resin material that can fuse with each other by heat onto the barrier substrate or the second substrate. Examples of adhesive layers include the following:

[0137] <Stretched base material> The stretched substrate is made of polypropylene. The polypropylene used can be the type described in the section on polypropylene substrates above; a detailed explanation is omitted here.

[0138] The polypropylene content in the stretched substrate is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0139] The stretched substrate may contain resin materials other than polypropylene. Examples of resin materials include polyolefins such as polyethylene, (meth)acrylic resins, vinyl resins, cellulose resins, polyamides, polyesters, and ionomer resins. The stretched substrate may contain the above-mentioned additives.

[0140] The stretched substrate is a substrate that has undergone a stretching treatment. The stretching treatment may be uniaxial stretching or biaxial stretching. In one embodiment, the stretched substrate is a biaxially stretched polypropylene substrate.

[0141] When stretching in the longitudinal direction (the direction of substrate flow, MD direction), the stretching ratio is preferably 2 times or more and 15 times or less, more preferably 5 times or more and 13 times or less. When stretching in the transverse direction (the direction perpendicular to the MD direction, TD direction), the stretching ratio is preferably 2 times or more and 15 times or less, more preferably 5 times or more and 13 times or less. By setting the stretching ratio to 2 times or more, the strength and heat resistance of the stretched substrate can be further improved, and the printability of the stretched substrate can also be improved. From the viewpoint of the breaking limit of the stretched substrate, a stretching ratio of 15 times or less is preferable.

[0142] The thickness of the stretched substrate is preferably 10 μm to 100 μm, more preferably 10 μm to 50 μm, and even more preferably 15 μm to 25 μm. If the thickness is above the lower limit, for example, the strength and heat resistance of the barrier substrate can be further improved. If the thickness is below the upper limit, for example, the processability of the barrier substrate can be further improved.

[0143] In one embodiment, the stretched substrate may be subjected to the surface treatment described above. An easy-adhesion layer may be provided on the surface of the stretched substrate.

[0144] The barrier substrate may have a printed layer on the surface of the stretched substrate.

[0145] <Adhesive layer> In one embodiment, the barrier laminate includes an adhesive layer between the barrier substrate and the sealant layer. In one embodiment, the barrier laminate includes a first adhesive layer between the first substrate and the second substrate. In one embodiment, the barrier laminate includes a second adhesive layer between the second substrate and the sealant layer. This improves the adhesion between the barrier substrate and the sealant layer, the adhesion between the first substrate and the second substrate, and the adhesion between the second substrate and the sealant layer.

[0146] The adhesive layer is composed of an adhesive, which may be a one-component curing adhesive, a two-component curing adhesive, or a non-curing adhesive. The adhesive may be a solvent-free adhesive or a solvent-based adhesive.

[0147] Examples of solvent-free adhesives, i.e., non-solvent laminate adhesives, include polyether-based adhesives, polyester-based adhesives, silicone-based adhesives, epoxy-based adhesives, and urethane-based adhesives. Among these, urethane-based adhesives are preferred, and two-component curing type urethane-based adhesives are more preferred.

[0148] Examples of solvent-based adhesives include rubber-based adhesives, vinyl-based adhesives, olefin-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenol-based adhesives, and urethane-based adhesives. Among these, urethane-based adhesives are preferred, and two-component curing type urethane-based adhesives are more preferred.

[0149] The thickness of the adhesive layer is, for example, 0.1 μm to 10 μm, preferably 0.2 μm to 8 μm, and more preferably 0.5 μm to 6 μm.

[0150] [Packaging container] The barrier laminates of this disclosure can be suitably used for packaging material applications. The packaging material is used to manufacture a packaging container. The packaging material comprises the barrier laminate of the present disclosure. A packaging container can be manufactured by using at least the packaging material comprising the barrier laminate of the present disclosure.

[0151] The packaging containers of this disclosure comprise the barrier laminate of this disclosure (hereinafter also simply referred to as the "laminated"). Examples of packaging containers include packaging bags, tube containers, and containers with lids. A container with a lid comprises a container body having a storage compartment and a lid material joined (heat-sealed) to the container body to seal the storage compartment.

[0152] In one embodiment, the packaging container of this disclosure is suitable as a microwave oven container or a retort container because it can maintain gas barrier properties and interlayer adhesion strength even after high-temperature treatment. The packaging container of this disclosure is also suitable as a microwave oven retort container. The packaging container of this disclosure is particularly suitable as a retort pouch.

[0153] Examples of heat sealing methods include bar seals, rotary roll seals, belt seals, impulse seals, high-frequency seals, and ultrasonic seals.

[0154] Examples of packaging bags include various types such as standing pouch type, side seal type, two-side seal type, three-side seal type, four-side seal type, envelope seal type, gusset seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, and gusset type.

[0155] The packaging container may be equipped with an easy-open section. Examples of easy-open sections include a notch that serves as the starting point for tearing the packaging container, and a half-cut line formed by laser processing or a cutter as a path when tearing the packaging container.

[0156] The packaging container may be equipped with a steam venting mechanism. The steam venting mechanism is configured to allow steam to escape by connecting the inside and outside of the packaging container when the steam pressure inside the packaging container exceeds a predetermined value, while also preventing steam from escaping from other parts of the container.

[0157] The steam venting mechanism includes, for example, a steam venting seal protruding inward from the side seal portion of the packaging container, and an unsealed portion isolated from the contents storage portion by the steam venting seal portion. The unsealed portion communicates with the outside of the packaging container. The packaging container, filled with contents and with its opening heat-sealed, is heated using a microwave oven or the like. This increases the internal pressure, causing the steam venting seal portion to detach. Steam escapes to the outside of the packaging container through the detached steam venting seal portion and the unsealed portion.

[0158] In one embodiment, a packaging bag can be made by folding the laminate of the present disclosure in half so that the barrier substrate is on the outside and the sealant layer is on the inside, overlapping the two halves, and then heat-sealing the edges. In another embodiment, a packaging bag can be made by overlapping multiple laminates of the present disclosure so that the sealant layers face each other, and then heat-sealing the edges. The entire packaging bag may be made of the above laminate, or only a part of the packaging bag may be made of the above laminate.

[0159] In one embodiment, the laminate of the present disclosure is used as a lid material for a container with a lid.

[0160] Examples of contents that can be contained in the packaging container include liquids, solids, powders, and gels. The contents may be food or beverages, or non-food items such as chemicals, cosmetics, and pharmaceuticals. After the contents are placed in the packaging container, the container can be sealed by heat-sealing the opening.

[0161] As specific examples of packaging bags, small bags and standing pouches will be described below. A small pouch is a small packaging bag used to contain contents weighing, for example, 1g to 200g. Examples of contents that can be contained in a small pouch include sauces, soy sauce, dressings, ketchup, syrups, cooking alcoholic beverages, other liquid or viscous seasonings; liquid soups, powdered soups, fruit juices; spices; liquid beverages, jelly beverages, instant foods, and other food and beverages.

[0162] Standing pouches are used to contain contents ranging from 50g to 2000g. Examples of contents that can be contained in standing pouches include shampoo, rinse, conditioner, hand soap, body soap, fragrances, deodorizers, insect repellents, detergents; dressings, cooking oils, mayonnaise, and other liquid or viscous condiments; liquid beverages, jelly beverages, instant foods, and other food and beverages; and creams.

[0163] Figure 9 shows a packaging bag 50 obtained by bonding two laminates together. The shaded area indicates a heat-sealed portion. The packaging bag 50 may also be equipped with an easy-open section 51. Examples of the easy-open section 51 include a notch 52 that serves as a starting point for tearing, and a half-cut line 53 formed by laser processing or a cutter as a tearing path.

[0164] Figure 10 shows a simplified example of the configuration of a standing pouch. The shaded area indicates a heat-sealed portion. In one embodiment, the standing pouch 60 comprises a body (side sheet) 61 and a bottom (bottom sheet) 62. The side sheet 61 and the bottom sheet 62 may be made of the same material or of different materials. The bottom sheet 62 maintains the shape of the side sheet 61, thereby giving the pouch self-supporting ability and enabling it to be a standing pouch. A storage space for containing contents is formed within the area enclosed by the side sheet 61 and the bottom sheet 62.

[0165] The standing pouch 60 may be equipped with a steam venting mechanism 63. The steam venting mechanism 63 comprises a steam venting seal portion 63a that protrudes inward from the side seal portion toward the inside of the packaging container, and an unsealed portion 63b that is isolated from the contents containment portion by the steam venting seal portion 63a. The unsealed portion 63b is in communication with the outside of the packaging container.

[0166] In a standing pouch, the body may be made only of the laminate of the Disclosure, the bottom may be made only of the laminate of the Disclosure, or both the body and the bottom may be made of the laminate of the Disclosure.

[0167] In one embodiment, the side sheet can be formed by manufacturing a bag such that the sealant layer of the laminate of the present disclosure is the innermost layer. In another embodiment, the side sheet can be formed by preparing two laminates of the present disclosure, overlapping them so that the sealant layers face each other, and heat-sealing the side edges on both sides to form a bag.

[0168] In another embodiment, the side sheet can be formed by preparing two laminates of the present disclosure, overlapping them so that the sealant layers face each other, and inserting two V-shaped folded laminates with the sealant layers facing outwards into the gaps between the laminates at the side edges on both sides of the overlapped laminates, and then heat-sealing them. According to this manufacturing method, a standing pouch having a body with side gussets can be obtained.

[0169] In one embodiment, the bottom sheet can be formed by inserting the laminate of the present disclosure between the lower parts of the bag-formed side sheets and heat-sealing it. More specifically, the bottom sheet can be formed by inserting a laminate folded in a V-shape with the sealant layer facing outwards between the lower parts of the bag-formed side sheets and heat-sealing it.

[0170] In one embodiment, two of the above-mentioned laminates are prepared and stacked so that the sealant layers face each other. Then, the other laminate is folded into a V-shape so that the sealant layer faces outwards, and this is sandwiched between the bottoms of the two stacked laminates and heat-sealed to form the bottom. Next, the two sides adjacent to the bottom are heat-sealed to form the body. In this way, a standing pouch of one embodiment can be formed.

[0171] This disclosure relates, for example, to the following [1] to

[13] . [1] A barrier substrate comprising a polypropylene substrate having a first surface layer and a second surface layer, and a gas barrier layer provided on the first surface layer, wherein the polypropylene substrate is a stretched substrate, the first surface layer contains first particles, the average particle diameter of the first particles is 0.5 μm or more and 3.5 μm or less, and the content of the first particles in the first surface layer is 50 ppm or more and 1,800 ppm or less, based on the mass of the first surface layer. [2] The barrier substrate according to [1] above, wherein the second surface layer contains second particles, the average particle diameter of the second particles is 1.0 μm or more and 10 μm or less, and the content of the second particles in the second surface layer is 500 ppm or more and 4,000 ppm or less, based on the mass of the second surface layer. [3] The barrier substrate according to [2] above, wherein the first particles and the second particles are each independently at least one selected from silica, aluminum oxide, magnesium oxide, calcium oxide, titanium oxide, zinc oxide, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, magnesium carbonate, calcium carbonate, calcium sulfate, barium sulfate, magnesium silicate, aluminum silicate, calcium silicate, aluminosilicate, kaolin, talc, diatomaceous earth, and resin particles. [4] A barrier substrate according to any one of [1] to [3] above, wherein the gas barrier layer has a vapor-deposited film composed of an inorganic oxide. [5] The barrier substrate according to [4] above, wherein the inorganic oxide constituting the deposited film contains silicon carbide oxide, silicon dioxide, or aluminum oxide. [6] The barrier substrate according to [4] or [5] above, wherein the barrier substrate further comprises an anchor coat layer between the polypropylene substrate and the vapor-deposited film. [7] The barrier substrate according to any one of [4] to [6] above, wherein the gas barrier layer further comprises a barrier coat layer on the surface of the vapor-deposited film opposite to the surface facing the polypropylene substrate. [8] A barrier laminate comprising a barrier substrate as described in any of [1] to [7] above and a sealant layer. [9] A barrier laminate comprising a first substrate, a second substrate, and a sealant layer in this order in the thickness direction, wherein either the first substrate or the second substrate is a barrier substrate as described in any of [1] to [7] above, and the other of the first substrate or the second substrate is a stretched substrate made of polypropylene.

[10] The barrier laminate according to [8] or [9] above, wherein the sealant layer is a resin layer made of polypropylene.

[11] A barrier laminate according to any of [8] to

[10] above, used for packaging container applications.

[12] A packaging container comprising a barrier laminate as described in any of [8] to

[11] above.

[13] The packaging container described in

[12] above, which is a retort pouch. [Examples]

[0172] The barrier substrates of this disclosure will be described in detail below based on the examples provided.

[0173] [Example 1] The main component was prepared by diluting a hydroxyl group-containing (meth)acrylic resin (number average molecular weight: 25,000, glass transition temperature: 85°C, hydroxyl value: 80 mg KOH / g) and 3-glycidoxypropyltriethoxysilane (silane coupling agent) with a mixed solvent of methyl ethyl ketone and ethyl acetate (mixing ratio 1:1) so that the solid content concentration of the (meth)acrylic resin in the solution was 10% by mass and the concentration of the silane coupling agent was 1.5% by mass.

[0174] An ethyl acetate solution containing xylylene diisocyanate (75% solids by mass) was added to the main component as a curing agent to obtain an anchor coating agent. The amount of curing agent used was 8 parts by mass per 100 parts by mass of the main component.

[0175] A biaxially oriented polypropylene film (OPP, stretching ratio in the longitudinal direction: 5x, stretching ratio in the transverse direction: 10x) with a thickness of 20 μm was prepared as the polypropylene substrate. The OPP has a first surface layer with a thickness of 1 μm, an intermediate layer with a thickness of 18 μm, and a second surface layer with a thickness of 1 μm. The first surface layer contains 200 ppm of silica particles with an average particle diameter of 1.5 μm. The second surface layer contains 2,000 ppm of silica particles with an average particle diameter of 4 μm. The first surface layer is corona treated.

[0176] The above-mentioned anchor coating agent was applied to the corona-treated surface of a biaxially oriented polypropylene film and dried at 80°C for 2 seconds to form an anchor coating layer with a thickness of 0.2 μm. Within 4 weeks after the formation of the anchor coating layer, a silicon oxide vapor-deposited film with a thickness of 30 nm was formed by PVD.

[0177] A solution was obtained by mixing 47.69 g of water, 22.8 g of isopropyl alcohol, and 1.13 g of 0.5 N hydrochloric acid. To this solution, 27.04 g of tetraethoxysilane as a metal alkoxide and 1.35 g of vinyltrimethoxysilane as a silane coupling agent were mixed while cooling to 10°C to obtain solution A. Solution B was obtained by mixing 4.14 g of polyvinyl alcohol with a degree of saponification of 99% or more and a degree of polymerization of 2,400 as a water-soluble polymer, 91.07 g of water, and 4.79 g of isopropyl alcohol. A barrier coating agent was obtained by mixing solution A and solution B in a mass ratio of solution A / solution B of 65.5 / 34.5.

[0178] Within four weeks after the vapor-deposited film was formed, the following barrier coat layer was created. Specifically, a barrier coat agent with the above composition was applied to the vapor-deposited film using a gravure coater and dried at 100°C for 8 seconds to form a 0.3 μm thick barrier coat layer made of a composite polymer. In this manner, a barrier substrate was obtained.

[0179] [Example 2] A barrier substrate was obtained in the same manner as in Example 1, except that the average particle size and content of silica particles in the first and second surface layers of the OPP were changed as shown in Table 1, and a 30 nm thick carbon-containing silicon oxide vapor-deposited film was formed on the anchor coat layer by CVD. Using a real low-temperature plasma chemical vapor deposition apparatus, the carbon-containing silicon oxide vapor-deposited film was formed on the anchor coat layer under the following formation conditions while applying tension to the film by roll-to-roll. In Table 1, the intermediate layer of the OPP is omitted.

[0180] (Formation conditions) Hexamethyldisiloxane:Oxygen gas:Helium = 1:10:10 (unit: slm) • Cooling / electrode drum power supply: 22kW Line speed: 100m / min

[0181] The proportions of carbon (C), silicon (Si), and oxygen (O) in a carbon-containing silicon oxide vapor-deposited film were measured. The proportions of carbon (C), silicon (Si), and oxygen (O) were 32.7%, 29.8%, and 37.5%, respectively, relative to the total of 100% of the three elements (silicon, oxygen, and carbon). The proportions of each element were determined by narrow-scan analysis using X-ray photoelectron spectroscopy (XPS) under the measurement conditions described above.

[0182] [Examples 3 and 4, and Comparative Examples 2 and 3] A barrier substrate was obtained in the same manner as in Example 2, except that the type of particles, average particle size, and content in the first and second surface layers of the OPP were changed as shown in Table 1.

[0183] [Example 5 and Comparative Example 1] A barrier substrate was obtained in the same manner as in Example 1, except that the average particle size and content of silica particles in the first and second surface layers of the OPP were changed as shown in Table 1, and a 9 nm thick aluminum oxide vapor-deposited film was formed by PVD.

[0184] [Fabrication of barrier laminates] The biaxially oriented polypropylene film surface of the above barrier substrate was corona-treated. A 20 μm thick biaxially oriented polypropylene film (Toyobo Co., Ltd., P2171) was used as the first substrate, and the corona-treated barrier substrate was used as the second substrate. A 60 μm thick unoriented polypropylene film (Toray Film Processing Co., Ltd., ZK207) was used as the sealant layer. These were dry-laminated via a polyester urethane adhesive (Rock Paint, RU-004 / H-1 (mixing ratio 7.5 / 1)), and left to stand at 40°C for 72 hours to obtain a barrier laminate. The thickness of the adhesive layer formed by the polyester urethane adhesive was 4 μm. The barrier substrate was arranged so that the barrier coat layer faced the first substrate side and the polypropylene substrate faced the sealant layer side (see Figure 7).

[0185] [Coefficient of dynamic friction] In accordance with JIS K7125:1999 "Plastics - Films and Sheets - Test Method for Coefficient of Friction", the coefficient of dynamic friction between the barrier coating layer surface of a barrier substrate and a metal plate, and the coefficient of dynamic friction between the OPP surface of the barrier substrate and a metal plate were measured. A stainless steel plate with a smooth surface was used as the metal plate. The measurement conditions for the coefficient of dynamic friction were: load of the sliding piece: 1.96 N, contact area of ​​the sliding piece: 40 cm² 2 The test speed was set to 100 mm / min.

[0186] [Gas barrier performance evaluation] The barrier substrate obtained above was cut out to obtain a test specimen. Using this test specimen, the oxygen permeability (cc / m³) was measured. 2 (day·atm) and water vapor transmission rate (g / m³) 2 The following method was used to measure the day(s). Units are omitted in Table 1.

[0187] Using an oxygen permeability measuring device (MOCON, OX-TRAN2 / 20), the OPP side of the test specimen was set to face the oxygen supply side, and the oxygen permeability was measured in accordance with JIS K 7126 under conditions of 23°C and 90% RH relative humidity.

[0188] Using a water vapor transmission rate measuring device (MOCON, PERMATRAN-w 3 / 33), the test specimen was set with the OPP side facing the water vapor supply side, and the water vapor transmission rate was measured in accordance with JIS K 7129 under conditions of 40°C and 90% RH relative humidity.

[0189] [Table 1] [Explanation of symbols]

[0190] 1: Barrier substrate, 2: Barrier laminate, 3: Stretched substrate, 10: Polypropylene substrate, 10a: First surface layer, 10b: Second surface layer, 11: Anchor coat layer, 12: Vapor-deposited film, 14: Barrier coat layer, 20, 20A, 20B: Adhesive layer, 30: Sealant layer, 50: Packaging bag, 51: Easy-open section, 52: Notch section, 53: Half-cut line, 60: Standing pouch, 61: Body (side sheet), 62: Bottom (bottom sheet), 63: Steam venting mechanism, 63a: Steam venting seal, 63b: Unsealed part A: Vacuum vessel, B: Unwinding section, C: Film deposition drum, D: Winding section, E: Conveyor roll, F: Evaporation source, G: Reaction gas supply section, H: Anti-adhesion box, I: Evaporation material, J: Plasma gun, S: Substrate, A1: Vacuum vessel, B1: Unwinding section, C1: Cooling / electrode drum, D1: Winding section, E1: Conveyor roll, F1: Glow discharge plasma, G1: Reaction gas supply section, H1: Raw material supply nozzle, I1: Raw material gas supply section, J1: Magnet, K1: Power supply, L1: Vacuum pump

Claims

1. A polypropylene substrate having a first surface layer and a second surface layer, A gas barrier layer provided on the first surface layer and A barrier substrate comprising, The aforementioned polypropylene substrate is a substrate that has undergone stretching treatment. The first surface layer contains first particles, the average particle diameter of the first particles is 0.5 μm or more and 3.5 μm or less, and the content of the first particles in the first surface layer is 50 ppm or more and 1,800 ppm or less, based on the mass of the first surface layer. Barrier substrate.

2. The second surface layer contains the second particles, The average particle diameter of the second particle is 1.0 μm or more and 10 μm or less. The content of the second particles in the second surface layer is 500 ppm or more and 4,000 ppm or less, based on the mass of the second surface layer. The barrier substrate according to claim 1.

3. The barrier substrate according to claim 2, wherein the first particles and the second particles are each independently at least one selected from silica, aluminum oxide, magnesium oxide, calcium oxide, titanium oxide, zinc oxide, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, magnesium carbonate, calcium carbonate, calcium sulfate, barium sulfate, magnesium silicate, aluminum silicate, calcium silicate, aluminosilicate, kaolin, talc, diatomaceous earth, and resin particles.

4. The barrier substrate according to any one of claims 1 to 3, wherein the gas barrier layer has a vapor-deposited film composed of an inorganic oxide.

5. The barrier substrate according to claim 4, wherein the inorganic oxide constituting the vapor-deposited film includes silicon carbide oxide, silicon oxide, or aluminum oxide.

6. The barrier substrate according to claim 4 or 5, wherein the barrier substrate further comprises an anchor coat layer between the polypropylene substrate and the vapor-deposited film.

7. The barrier substrate according to any one of claims 4 to 6, wherein the gas barrier layer further comprises a barrier coat layer on the surface of the vapor-deposited film opposite to the surface facing the polypropylene substrate.

8. A barrier substrate according to any one of claims 1 to 7, sealant layer and A barrier laminate comprising the following features.

9. The first substrate, the second substrate, and the sealant layer are arranged in this order in the thickness direction. Either the first substrate or the second substrate is a barrier substrate according to any one of claims 1 to 7, and the other of the first substrate or the second substrate is a stretchable substrate made of polypropylene. Barrier laminate.

10. The barrier laminate according to claim 8 or 9, wherein the sealant layer is a resin layer made of polypropylene.

11. A barrier laminate according to any one of claims 8 to 10, used for packaging container applications.

12. A packaging container comprising a barrier laminate according to any one of claims 8 to 11.

13. The packaging container according to claim 12, which is a retort pouch.

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