Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/10—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of paper or cardboard
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
  • B65D65/38—Packaging materials of special type or form
  • B65D65/40—Applications of laminates for particular packaging purposes
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/10—Coatings without pigments
  • D21H19/14—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12
  • D21H19/20—Coatings without pigments applied in a form other than the aqueous solution defined in group D21H19/12 comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H19/00—Coated paper; Coating material
  • D21H19/80—Paper comprising more than one coating
  • D21H19/82—Paper comprising more than one coating superposed

Definitions

• the present invention relates to a packaging laminate suitable for use as a bag, and a packaging material comprising the laminate.
• plastic waste has become more serious.
• the world's plastic production is said to exceed 400 million tons/year, and among them, plastic production in the packaging and container sector is large, causing plastic waste.
• Plastic does not decompose semi-permanently, and its garbage turns into microplastics in the natural environment, which has a serious adverse effect on the ecosystem.
• the most commonly used plastics for packaging containers are polyethylene terephthalate (PET), which is used for beverage bottles, etc., and polyethylene (PE) and polypropylene (PP), which are used for laminating plastic bags and containers.
• PET polyethylene terephthalate
• PE polyethylene
• PP polypropylene
• Patent Document 1 Although it has been proposed to replace plastic with paper as a means of immediate effect (Patent Document 1), the gas barrier properties of plastic films, particularly PET films and nylon (Ny) films, are significantly inferior to those of plastic films. Paper cannot simply replace plastic film in applications where durability is required.
• An object of the present invention is to provide a packaging laminate and a packaging material that have excellent gas barrier properties and can reduce the amount of plastic used.
• the present invention comprises a paper substrate, an undercoat layer, a gas barrier coat layer and a heat seal layer, the undercoat layer being disposed adjacent to the paper substrate and the gas barrier coat layer being adjacent to the undercoat layer.
• the undercoat layer is a dry coating film of a water-based coating agent containing an acrylic emulsion, and the surface of the undercoat layer facing the gas barrier coating layer has an arithmetic mean roughness Ra of 5.0 ⁇ m or less and a Cobb water absorbency of 10.
• the present invention relates to a laminate having a weight of 0 g/m 2 or less, and a packaging material comprising the laminate.
• the present invention it is possible to provide a packaging laminate that has excellent gas barrier properties and can reduce the amount of plastic used.
• the laminate of the present invention comprises an undercoat layer, a gas barrier coat layer and a heat seal layer, the undercoat layer being arranged adjacent to the paper substrate, and the gas barrier coat layer being arranged adjacent to the undercoat layer.
• the undercoat layer is a dry coating film of a water-based coating agent containing an acrylic emulsion, and the surface of the undercoat layer facing the gas barrier coating layer has an arithmetic mean roughness Ra of 5.0 ⁇ m or less and a Cobb water absorbency of 10.0 ⁇ m. 0 g/m 2 or less.
• the laminate of the present invention will be described in detail below.
• the paper substrate used in the present embodiment is not particularly limited, and known paper substrates containing pulp as a main component can be used. Bleached or unbleached kraft paper, woodfree paper, paperboard, liner paper, coated paper, one-sided glossy paper, glassine paper, graphane paper, recycled paper, and the like. Also, it is preferable to use FSC-certified paper.
• the basis weight of the paper base material is appropriately adjusted depending on the purpose, and is, for example, 10 to 400 g/m 2 . If the basis weight is less than 10 g/m 2 , the strength as a packaging material is poor.
• the pulp that is the main component of the paper base material includes chemical pulps such as LBKP (bleached hardwood kraft pulp), NBKP (bleached softwood kraft pulp), LUKP (unbleached hardwood kraft pulp), NUKP (unbleached softwood kraft pulp), GP (ground wood pulp), PGW (pressurized ground wood pulp), RMP (refiner mechanical pulp), TMP (thermomechanical pulp), CTMP (chemi-thermomechanical pulp), CMP (chemi-mechanical pulp), CGP (chemi-grand pulp), etc. mechanical pulp, DIP (deinked pulp) and other wood pulps and non-wood pulps such as kenaf, bagasse, bamboo, cotton, and Manila hemp can be used. These can be used alone or mixed in any ratio.
• chemical pulps such as LBKP (bleached hardwood kraft pulp), NBKP (bleached softwood kraft pulp), LUKP (unbleached hardwood kraft pulp), NUKP (unbleached softwood kraft pulp), GP
• Hardwood pulp has relatively short fibers and tends to work against tensile elongation at break.
• softwood pulp and non-wood pulp have longer fibers than hardwood pulp, have higher strength, and tend to increase tensile elongation at break.
• softwood pulp such as NBKP (softwood bleached kraft pulp) or NUKP (softwood unbleached kraft pulp) in an amount of 5 parts by mass or more in the pulp. Practically sufficient strength when used as a bag, and excellent water resistance and oil resistance.
• a pulp containing 5-20% by weight of NBKP (bleached softwood kraft pulp) and 95-80% by weight of LBKP (bleached hardwood kraft pulp) is used.
• NBKP bleacheched softwood kraft pulp
• LBKP bleacheched hardwood kraft pulp
• Paper substrates containing fillers can also be used.
• fillers include light calcium carbonate, heavy calcium carbonate, talc, clay, kaolin, calcined clay, titanium dioxide, and aluminum hydroxide.
• the filler content in the paper substrate is, for example, 1 to 30 parts by weight with respect to 100 parts by weight of dry pulp.
• 1 to 15 parts by mass, preferably 2 to 10 parts by mass of light calcium carbonate may be included with respect to 100 parts by mass of dry pulp.
• the paper base material may contain various known papermaking additives.
• papermaking additives include sizing agents, water-soluble polymers, internal paper strength enhancers such as wet paper strength enhancers, bulking agents, retention aids, drainage improvers, coloring dyes, coloring pigments, fluorescent Whitening agents, fluorescent decolorizing agents, pitch control agents and the like can be mentioned.
• Sizing agents include neutral rosin sizing agents, strengthened rosin sizing agents, acidic rosin sizing agents, weakly acidic rosin sizing agents, AKD (alkylketene dimer), ASA (alkenyl succinic anhydride), and the like. It is preferable to use a paper base material containing 0.05 to 1.0 parts by mass, more preferably 0.1 to 0.5 parts by mass of a neutral rosin sizing agent per 100 parts by mass of pulp. By containing a sizing agent, when a heat sealing agent or the like is applied, penetration of the coating liquid into the paper base material is moderately suppressed, resulting in a laminate having excellent water resistance and oil resistance.
• water-soluble polymers examples include starches such as corn starch, potato starch, tapioca starch, cross-linking agent-modified starch, oxidized starch, enzyme-modified starch, esterified starch, etherified starch, cationic starch, and amphoteric starch. , polyvinyl alcohol, polyacrylamide, and the like can be used. Starch and polyacrylamide are particularly preferred.
• the amount of the water-soluble polymer added is 0.05 parts by mass or more with respect to 100 parts by mass of pulp. More preferably, it is 0.1 parts by mass or more. For example, 0.1 to 10 parts by mass, preferably 0.1 to 7.0 parts by mass of the water-soluble polymer is contained with respect to 100 parts by mass of pulp.
• 0.1 to 7.0 parts by mass preferably 0.1 to 5.0 parts by mass of polyacrylamide and/or 0.1 to 3.0 parts by mass, with respect to 100 parts by mass of pulp
• 0.1 to 2.0 parts by mass of starch preferably cationized starch
• Known methods such as internal addition and coating (size press, air knife coater, etc.) can be used as the method of containing.
• the paper-making method for the paper substrate is not particularly limited, and includes a fourdrinier paper machine, a fourdrinier multi-layer paper machine, a cylinder paper machine, a fourdrinier multi-layer paper machine, a fourdrinier cylinder combi multi-layer paper machine, and a twin wire paper machine. It can be manufactured by various paper machines such as Further, in the present invention, the paper base material may be a single-layer paper, a multi-layer paper, or a laminate of multiple layers.
• a pigment coating layer may be provided on the paper substrate.
• the pigment coating layer is formed by applying a coating liquid containing a pigment and a binder.
• a coating liquid containing a pigment and a binder As the pigment, known pigments used in the coating layer of general coated printing paper can be used. Examples include calcium carbonate (heavy calcium carbonate, light calcium carbonate, etc.), kaolin (including clay).
• calcined clay talc, magnesium carbonate, barium sulfate, calcium sulfate, titanium dioxide, zinc oxide, zinc sulfate, zinc carbonate, calcium silicate, aluminum silicate, magnesium silicate, diatomaceous earth, aluminum hydroxide, inorganic pigments such as magnesium hydroxide, Alternatively, acrylic, styrene, vinyl chloride, nylon itself, and organic pigments (so-called plastic pigments) obtained by copolymerizing these may be used. For example, a combination of 20 to 40 parts by weight of kaolin and 60 to 80 parts by weight of ground calcium carbonate can be used as the pigment.
• known adhesives used in the coating layers of general coated printing papers can be used.
• starches such as etherified starch, cationic starch, and amphoteric starch; water-soluble polymers such as gelatin, casein, soybean protein, and polyvinyl alcohol; vinyl acetate, ethylene vinyl acetate, polyurethane resins, acrylic resins, polyester resins , polyamide-based resins, and other synthetic resins.
• the mixing ratio of the pigment and the binder in the coating agent is not particularly limited, but it is preferable to use 5 to 50 parts by weight of the binder per 100 parts by weight of the pigment.
• a combination of 1 to 5 parts by weight of starch phosphate and 5 to 15 parts by weight of styrene-butadiene latex can be used as a binder for 100 parts by weight of pigment.
• the coating agent may contain various auxiliary agents as long as they do not impair the intended effect of the present invention. UV absorbers, stabilizers, antistatic agents, cross-linking agents, sizing agents, optical brighteners, colorants, pH adjusters, antifoaming agents, plasticizers and preservatives may be included.
• the coating amount of such a coating agent is, for example, 2 to 40 g/m 2 in terms of solid content per side of the paper base paper.
• the surface on which the undercoat layer is provided preferably has an arithmetic mean roughness Ra2 of 6.0 ⁇ m or less.
• the arithmetic mean roughness Ra2 exceeds 6.0 ⁇ m, it is necessary to apply a large amount of water-based coating agent so that the arithmetic mean roughness Ra1 of the surface of the undercoat layer facing the gas barrier coat layer is 5.0 ⁇ m or less.
• a method for measuring the arithmetic mean roughness Ra2 will be described later.
• the undercoat layer is a layer formed by applying a water-based coating agent containing an acrylic emulsion to a paper base material and drying it.
• the arithmetic mean roughness R1 of the surface of the undercoat layer (the surface of the undercoat layer opposite to the paper substrate and the surface on which the gas barrier coat layer described later is provided) is 5.0 ⁇ m or less, and
• the Cobb water absorbency is 10.0 g/m 2 or less. Thereby, a laminate having excellent gas barrier properties can be obtained.
• the Cobb water absorbency in this specification is the amount of water absorbed by the paper per unit area when it is in contact with water for 60 seconds according to the Cobb method defined in JIS-P-8140.
• the aqueous coating agent used in the present invention is obtained by, for example, neutralizing a polymer obtained by emulsion polymerization of a monomer composition (i) containing an anionic polymerizable monomer having a carboxyl group in an aqueous medium with an alkaline compound. After obtaining a hydrated product, the monomer composition (ii) containing a hydrophobic monomer is emulsion-polymerized in the presence of the neutralized product.
• anionic polymerizable monomers having a carboxyl group examples include ⁇ , ⁇ -unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid, monomethyl maleate, and maleic acid.
• carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, and citraconic acid, monomethyl maleate, and maleic acid.
• ⁇ such as monoethyl acid, monopropyl maleate, monobutyl maleate, monomethyl fumarate, monoethyl fumarate, monopropyl fumarate, monobutyl fumarate, monomethyl itaconate, monoethyl itaconate, monopropyl itaconate, and monobutyl itaconate; ⁇ -unsaturated dicarboxylic acid half-esters and the like can be mentioned, and one kind or two or more kinds can be used in combination. Acrylic acid and methacrylic acid are preferably used.
• the monomer composition (i) may contain polymerizable monomers other than anionic polymerizable monomers.
• Such monomers may be any of nonionic monomers, cationic monomers and anionic monomers.
• Nonionic monomers include (meth)acrylamide, N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide and N-isopropyl (meth)acrylamide, N-tert-butyl (meth)acrylamide, N-lauryl ( N-substituted monoalkyl (meth)acrylamides such as meth)acrylamide, N-tert-octyl (meth)acrylamide, N-cyclohexyl (meth)acrylamide,
• styrenes such as vinyltoluene and divinylbenzene; Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, normal butyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) ) acrylates and alkyl (meth)acrylates such as decyl (meth)acrylate,
• Examples include dialkyl esters of unsaturated dicarboxylic acids such as maleic acid and fumaric acid, and vinyl esters such as vinyl acetate and vinyl propionate.
• Cationic monomers include mono- or di-alkyl)aminoalkyl (meth)acrylates, (mono- or di-alkyl)aminohydroxylalkyl (meth)acrylates, (mono- or di-alkyl)aminoalkyl (meth)acrylamides , vinylpyridine, vinylimidazole, diallylamine, and the like.
• anionic monomers examples include sulfonic acid group-containing monomers such as vinylsulfonic acid, (meth)allylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid and sulfonated styrene, phosphate esters of hydroxyalkyl (meth)acrylates, and the like. and salts of these alkali compounds.
• the polymerization method of the monomer composition (i) conventionally known methods can be used, including a batch addition polymerization method in which all the monomers are charged in a reaction vessel at once and polymerized, and a part or all of the monomers are divided into reaction vessels. It is possible to use a split addition polymerization method in which the monomers are added and polymerized, and a continuous dropping polymerization method in which a part or all of the monomers are continuously dropped into a reaction vessel while polymerizing.
• a surfactant can be used as necessary during the polymerization reaction.
• nonionic, anionic, amphoteric surfactants, and surfactants having a polymerizable group can be used.
• Nonionic surfactants include polyoxyalkylene alkylphenyl ether, polyoxyalkylene alkyl ether, polyoxyalkylene fatty acid ester, polyoxypropylene polyoxyethylene glycol glycerin fatty acid ester, sorbitan fatty acid ester, polyethylene glycol fatty acid ester, polyoxyethylene sorbitan Fatty acid esters, sucrose fatty acid esters, pentaerythritol fatty acid esters, propylene glycol fatty acid esters, fatty acid diethanolamides, polyoxypropylene polyoxyethylene glycol and the like.
• anionic surfactants include phosphoric acid esters of compounds such as polyoxyalkylene alkylphenyl ethers, polyoxyalkylene monostyrylphenyl ethers, polyoxyalkylene distyrylphenyl ethers, polyoxyalkylene alkyl ethers, and polyoxyalkylene fatty acid esters.
• amphoteric surfactants include surfactants having an anionic group and a cationic group, and surfactants in which the anionic group is an alkali metal salt such as a sodium salt or an amine salt. can be done.
• a surfactant having a polymerizable group is generally called a reactive emulsifier, and examples include compounds having a hydrophobic group, a hydrophilic group and a polymerizable group in the molecule.
• the polymerizable group for example, (meth) allyl group, 1-propenyl group, 2-methyl-1-propenyl group, isopropenyl group, vinyl group, (meth) acryloyl group or the like carbon-functionality having a carbon double bond including groups.
• polymerizable group-containing polyoxyalkylene ether compounds such as polyoxyalkylene alkyl ethers, polyoxyalkylene aralkyl ethers, and polyoxyalkylene phenyl ethers, which have one or more of the polymerizable groups in the molecule
• polyoxy polyoxyalkylene styryl phenyl ether compounds such as alkylene monostyryl phenyl ether and polyoxyalkylene distyryl phenyl ether;
• Polymerization initiators that can be used for polymerization include inorganic persulfates such as ammonium persulfate, potassium persulfate and sodium persulfate, organic peroxides such as tertiary butyl hydroperoxide, these inorganic persulfates or organic peroxides.
• redox polymerization catalysts by combining oxides and reducing agents, and azo catalysts such as 2,2'-azobisisobutyronitrile and 2,2'-azobis-2-methylpropionamidine dihydrochloride. is not limited to this. Two or more of these polymerization initiators may be used in combination.
• the amount of the polymerization initiator used can be adjusted as appropriate, but for example, it is 0.01 to 5 mol% of the total amount of the monomer composition (i).
• the polymerization initiator may be charged together with the monomer composition (i) into the reaction vessel, or may be continuously added dropwise.
• a known chain transfer initiator may be used for polymerization of the monomer composition (i).
• chain transfer initiators include alkyl mercaptan compounds such as normal octyl mercaptan, tert-lead decyl mercaptan, normal dodecyl mercaptan, normal octadecyl mercaptan, and normal hexadecyl mercaptan, thioglycolic acid derivatives, mercaptopropionic acid derivatives, mercaptoethanol, mercaptan derivatives such as thioethanol, thiomalic acid, and thiosalicylic acid; Two or more chain transfer agents may be used in combination.
• the amount of chain transfer agent used can be adjusted as appropriate, but for example, it is 0.01 to 2% by mass of the total amount of the monomer composition (i).
• the chain transfer agent may be charged together with the monomer composition (i) into the reaction vessel, or may be continuously added dropwise.
• the monomer concentration during polymerization is 15 to 50% by mass.
• the reaction temperature during polymerization is, for example, 40 to 95° C., and the reaction time is 1 to 20 hours.
• Alkaline compounds used in the neutralization reaction include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide.
• the amount of the alkali compound to be used is preferably 0.6 to 1 equivalent with respect to the anionic group equivalent of the anionic polymerizable monomer, that is, the anion equivalent. If the amount of the alkali compound used is less than 0.6 equivalent or more than 1 equivalent, sufficient dispersibility cannot be obtained, and the emulsion polymerizability of the hydrophobic monomer described later may be inferior.
• Hydrophobic monomers used in the monomer composition (ii) include styrenes such as styrene, ⁇ -methylstyrene, vinyltoluene, and divinylbenzene, methyl (meth)acrylate, ethyl (meth)acrylate, and propyl (meth)acrylate.
• Alkyl (meth)acrylates such as , normal butyl (meth)acrylate, isobutyl (meth)acrylate, tertiary butyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and decyl (meth)acrylate , dialkyl esters of unsaturated dicarboxylic acids such as maleic acid and fumaric acid, and vinyl esters such as vinyl acetate and vinyl propionate. You may use 2 or more types. It is preferable to use styrenes and (meth)acrylates having an alkyl group having 4 to 8 carbon atoms.
• the monomer composition (ii) may contain monomers other than hydrophobic monomers.
• Nonionic monomers such as (meth)acrylamide, N-substituted monoalkyl(meth)acrylamide, N-substituted dialkyl(meth)acrylamide, diacetoneacrylamide, and vinylpyrrolidone, (mono- or di-alkyl)aminoalkyl(meth) Cationic monomers such as acrylates, (mono- or di-alkyl)aminohydroxylalkyl (meth)acrylates, (mono- or di-alkyl)aminoalkyl (meth)acrylamides, vinylpyridines, vinylimidazoles, and diallylamine, (meth) Acrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid, monomethyl maleate, monoethyl maleate, monopropyl maleate, monobutyl maleate, monomethyl fumarate, monoeth
• the monomer composition (ii) is prepared by A method of emulsion polymerization using a radical polymerization catalyst in water may be mentioned.
• radical polymerization catalysts examples include inorganic persulfates such as ammonium persulfate, potassium persulfate and sodium persulfate, organic peroxides such as tertiary butyl hydroperoxide, and inorganic persulfates or organic peroxides thereof.
• redox polymerization catalysts in combination with a reducing agent azo catalysts such as 2,2'-azobisisobutyronitrile and 2,2'-azobis-2-methylpropionamidine dihydrochloride; Not limited.
• Two or more polymerization initiators may be used.
• polymerizing the monomer composition (ii) it is preferable to use 60 to 150 parts by mass of the alkali-neutralized polymer of the monomer composition (i) per 100 parts by mass of the monomer composition (ii).
• the same surfactant as used in the polymerization of the monomer composition (i) may be used.
• the polymerized monomer composition (ii) may be used as it is, or it may be used after being diluted with water or an aqueous solvent.
• water-based coating agents can also be used, including the HYDRECT (registered trademark) series manufactured by DIC Corporation and the Hervil (registered trademark) series manufactured by Daiichi Toryo Co., Ltd.
• the amount of the water-based coating agent applied is appropriately adjusted so that the surface arithmetic mean roughness R1 of the undercoat layer is 5.0 ⁇ m or less.
• An example is 1.0 g/m 2 to 15 g/m 2 (solid content).
• the lower limit of the arithmetic mean roughness R1 is not particularly limited, it is necessary to apply a large amount of water-based coating agent to make it less than 1.0 ⁇ m, while the gas barrier property is saturated. Therefore, from the viewpoint of balance with productivity, it is preferably 1.0 ⁇ m or more.
• the average length RSm of the contour curve elements on the surface of the undercoat layer is 150 ⁇ m or more. This makes it possible to obtain a laminate having more excellent gas barrier properties.
• the upper limit of RSm is not particularly limited, it is 700 ⁇ m as an example from the viewpoint of productivity. RSm is adjusted, for example, by the coating amount of the water-based coating agent.
• the arithmetic average roughness Ra (Ra1, Ra2) and the average length RSm of the profile curve element are values measured by a method conforming to JIS B0601:2001.
• RSm is the average of the length Xs of each profile curve element having m contour curve elements in the reference length (lr), and is a value obtained by the following formula.
• the coating method of the water-based coating agent is not particularly limited, and may be a spray method, a spin coating method, a dip method, a roll coating method, a blade coating method, a doctor roll method, a doctor blade method, a curtain coating method, a slit coating method, or a screen printing method.
• method, inkjet method, dispensing method, die coat (die coating) method, direct gravure method, reverse gravure method, flexo method, knife coat method, dot co-coat method, and the like can be used.
• the gas barrier coating layer is a layer formed by applying a gas barrier coating agent to the undercoat layer and drying it.
• a gas barrier coating agent conventionally known agents can be used, and an example thereof is one containing a vinyl alcohol polymer and an aqueous solvent. Specific examples include polyvinyl alcohol, ethylene vinyl alcohol and polyvinyl butyral.
• the vinyl alcohol polymer may have reactive functional groups other than hydroxyl groups, such as acetoacetyl groups, carboxyl groups, anionic carboxyl groups, sulfonic acid groups, and anionic sulfonic acid groups. These may be used individually by 1 type, and may use 2 or more types together.
• Vinyl alcohol polymers include hydrolysates of homopolymers or copolymers of vinyl esters, and compounds obtained by reacting hydrolysates of homopolymers or copolymers of vinyl esters with aldehydes or ketones to acetalize them. are mentioned.
• Examples of vinyl alcohol polymers having reactive functional groups other than hydroxyl groups include hydrolyzates of copolymers of vinyl esters and monomers having reactive functional groups, and homopolymers or copolymers of vinyl esters. Examples include those obtained by modifying the hydroxyl group or acetyl group of the decomposed product by a known method using a compound having a reactive functional group.
• Vinyl esters include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl caprylate, vinyl laurate, vinyl palmitate, vinyl stearate, Vinyl oleate, vinyl benzoate, vinyl acetoacetate and the like can be mentioned, and can be used alone or in combination of two or more. Preference is given to using vinyl acetate.
• Polymerizable compounds copolymerizable with vinyl esters include ethylene, propene, 1-butene, isobutylene, 1,3-butadiene, isopropenyl acetate, 2-propenyl acetate, styrene, ⁇ -methylstyrene, vinyl chloride, acrylonitrile, Maleic anhydride, methyl acrylate, methyl methacrylate, N-vinyl-N-methylformamide, vinylacetamide, N-vinylformamide, N-(hydroxymethyl)-N-vinylformamide, hydroxyethyl acrylate, methyl vinyl ketone, di Acetone acrylamide, diacetone acrylamide, diacetone methacrylamide, acrolein, formylstyrene, vinyl methyl ketone, vinyl ethyl ketone, vinyl isobutyl ketone, diacetone acrylate, diacetone methacrylate, acetonitrile acrylate, 2-
• the amount of these used can be adjusted as appropriate, but from the viewpoint of gas barrier properties, the blending amount of the polymerizable compound should be 60 mol% or less of the total amount of the vinyl ester and the polymerizable compound. It is preferable to keep it at 25 mol % or less, more preferably at most.
• the degree of polymerization of the vinyl ester polymer which is the precursor of the vinyl alcohol polymer
• it is, for example, 500 to 10,000, more preferably 800 to 6,000, and more preferably 1,000 to 3,000.
• a coating agent having an excellent balance between gas barrier properties and coatability can be obtained.
• the vinyl alcohol polymer has excellent gas barrier properties, it preferably has a degree of saponification of 90% or more, preferably 95% or more. It may be 100%.
• the degree of saponification can be measured by FTIR, for example using a Nicolet 5700 FTIR spectrometer controlled by OMNIC software.
• aldehydes used for acetalization include aliphatic aldehydes such as formaldehyde, acetaldehyde, propylaldehyde, butyraldehyde, octylaldehyde, and dodecylaldehyde; alicyclic aldehydes such as cyclohexanecarbaldehyde.
• aromatic aldehydes such as benzaldehyde, naphthaldehyde, anthraldehyde, phenylacetaldehyde, tolualdehyde, dimethylbenzaldehyde, cuminaldehyde, and benzaldehyde; unsaturated aldehydes such as cyclohexenealdehyde, dimethylcyclohexenealdehyde, and acrolein; furfural, 5-methylfurfural, and the like aldehydes having a heterocyclic ring; hemiacetals such as glucose and glucosamine; and aldehydes having an amino group such as 4-aminobutyraldehyde.
• Ketones include aliphatic ketones such as 2-propanone, methyl ethyl ketone, 3-pentanone and 2-hexanone; aliphatic ketones such as cyclopentanone and cyclohexanone; and aromatic ketones such as acetophenone and benzophenone. These can be used singly or in combination of two or more.
• organic acids and inorganic acids such as acetic acid, paratoluenesulfonic acid, nitric acid, sulfuric acid, and hydrochloric acid can be used as the acid catalyst used for acetalization.
• the vinyl alcohol-based polymer is preferably obtained by acetalizing a precursor with a degree of saponification of 95% or more.
• Examples of methods for modifying the hydroxyl group or acetyl group of a vinyl ester homopolymer or copolymer hydrolyzate include a method of directly reacting gaseous or liquid diketene, and a method of preliminarily adsorbing and absorbing an organic acid such as acetic acid.
• diketene is reacted by a method of reacting gaseous or liquid diketene in an inert gas atmosphere, or a method of spraying a mixture of organic acid and diketene to react (reaction generation step), and then , a method of washing and removing unreacted diketene using an alcohol having 1 to 3 carbon atoms (washing step), followed by drying under predetermined conditions (drying step);
• washing step a method of reacting a decomposed product with an acetoacetate for transesterification.
• an acetoacetyl group can be introduced into the vinyl alcohol polymer.
• Water-based solvents include water, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol; diols such as butanediol, pentanediol, and hexanediol; propylene glycol laurate; diethylene glycol ethers such as diethylene glycol monoethyl, diethylene glycol monobutyl, diethylene glycol monohexyl, carbitol; glycol ethers such as cellosolve, including propylene glycol ether, dipropylene glycol ether, and triethylene glycol ether; methanol, ethanol , isopropyl alcohol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, butyl alcohol, pentyl alcohol; sulfolane, esters, ketones, lactones such as ⁇ -butyrolact
• the gas barrier coating agent further includes a layered inorganic compound, a cross-linking agent capable of reacting with the functional group of the vinyl alcohol polymer, an inorganic filler, an antifoaming agent, a stabilizer (antioxidant, heat stabilizer, ultraviolet absorber, etc.), Plasticizers, antistatic agents, lubricants, antiblocking agents, colorants, leveling agents and the like may also be included.
• layered inorganic compounds examples include natural smectites such as montmorillonite, synthetic smectites, natural mica, synthetic mica, hydrotalcite and talc, and lipophilic treated smectites and lipophilic synthetic mica obtained by organically treating them.
• the use of the layered inorganic compound improves the gas barrier properties of the gas barrier coat layer.
• the blending amount of the layered inorganic compound is preferably 10 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the vinyl alcohol polymer.
• cross-linking agents examples include aldehydes such as formaldehyde, oxalic aldehyde, and glutaraldehyde; acetals such as diacetals of glutaraldehyde; araliphatic polyisocyanates such as xylylene diisocyanate and its derivatives; aromatic polyisocyanates such as toluene diisocyanate and its derivatives; and urethane prepolymers which are reaction products of these isocyanates and polyols.
• methylol ureas such as methylol urea and methylol melamine
• Carboxyl group-containing polymers carbodiimides such as p-phenylene-bis(2,6-xylylcarbodiimide), tetramethylene-bis(t-butylcarbodiimide), cyclohexane-1,4-bis(methylene-t-butylcarbodiimide) Hydrazine compounds such as methylene dihydrazine, ethylene dihydrazine, propylene dihydrazine, butylene dihydrazine, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide; hydrazide compounds such as dihydrazides and polyhydrazides;
• the blending amount of the cross-linking agent is appropriately adjusted, but as an example, it is 0.5 to 30 parts by mass with respect to 100 parts by mass of the vinyl alcohol polymer.
• gas barrier coating agent containing a vinyl alcohol polymer, an aqueous solvent, and a layered inorganic compound because it has excellent gas barrier properties. It is preferable to use a gas barrier coating agent containing an acetalized vinyl alcohol-based polymer, an aqueous solvent, and a cross-linking agent because of its excellent heat-sealing properties.
• gas barrier coating agents can also be used, examples of which include Exevier (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., SunBar (registered trademark) series manufactured by Sun Chemical Co., Ltd., and Takelac WPB (registered trademark) manufactured by Mitsui Chemicals, Inc. series, LG-OX manufactured by Tokyo Ink Co., Ltd., and the like.
• the coating amount of the gas barrier coating agent is appropriately adjusted depending on the desired degree of gas barrier properties . 0 g/ m2 .
• the coating method of the gas barrier coating agent is not particularly limited, and may be a spray method, a spin coating method, a dipping method, a roll coating method, a blade coating method, a doctor roll method, a doctor blade method, a curtain coating method, a slit coating method, or a screen printing method.
• method ink jet method, dispensing method, die coating (die coating) method, direct gravure method, reverse gravure method, flexographic method, knife coating method, dot co-coating method and the like can be used.
• a heat-sealing layer is formed by applying and drying a heat-sealing agent.
• the heat-sealing layer is placed directly or via any layer on the paper substrate or the gas barrier coating layer.
• the heat-sealing agent used to form the heat-sealing agent is not particularly limited, and may be a type in which a thermoplastic resin having heat-sealing properties is dissolved in an organic solvent, a type in which water or an aqueous organic solvent is dissolved, or a type in which water or an aqueous organic solvent is dissolved. It may be in any form, such as an emulsion type dispersed in a solvent.
• heat-sealable resins examples include shellacs, rosins, rosin-modified maleic acid resins, rosin-modified phenolic resins, nitrocellulose, cellulose acetate, cellulose acetylpropionate, cellulose acetylbutyrate, chlorinated rubber, cyclized rubber, Vinyl chloride, vinylidene chloride, polyamide resin, vinyl chloride-vinyl acetate copolymer, polyester resin, ketone resin, butyral resin, chlorinated polypropylene resin, chlorinated polyethylene resin, chlorinated ethylene vinyl acetate resin, ethylene vinyl acetate resin, acrylic Thermoplastic resins such as resins, urethane resins, ethylene-vinyl alcohol resins, styrene-maleic acid resins, casein and alkyd resins may be used, and these may be used singly or in combination of two or more.
• Thermoplastic resins such as resins, urethane resins
• the organic solvent is not particularly limited, and examples include aromatic hydrocarbons such as toluene, xylene, Solvesso #100 and Solvesso #150, aliphatic hydrocarbons such as hexane, heptane, octane, and decane, methyl acetate, and acetic acid.
• aromatic hydrocarbons such as toluene, xylene, Solvesso #100 and Solvesso #150
• aliphatic hydrocarbons such as hexane, heptane, octane, and decane, methyl acetate, and acetic acid.
• Various ester-based organic solvents such as ethyl, isopropyl acetate, butyl acetate, amyl acetate, ethyl formate, and butyl propionate can be used.
• Water-based organic solvents include alcohols such as methanol, ethanol, propanol and butanol; ketones such as acetone, methyl ethyl ketone and cyclohaxanone; ethylene glycol (mono, di) methyl ether; ethylene glycol (mono, di) ethyl ether; Glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol (mono, di)methyl ether, diethylene glycol (mono, di)ethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol (mono, di)methyl Ethers, glycol ethers such as propylene glycol (mono, di)methyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol (mono, di)methyl ether, and the like.
• the heat-sealing agent used for forming the heat-sealing layer further includes other components such as lubricants such as waxes and fillers, antifoaming agents, plasticizers, leveling agents, emulsifiers, dispersion stabilizers, surfactants, and tackifiers. , antiseptic agent, antibacterial agent, rust inhibitor, antioxidant, cross-linking agent, curing agent, curing catalyst, light stabilizer, ultraviolet absorber, photocatalytic compound, dye, inorganic pigment, organic pigment, extender pigment, antistatic agent etc. may be included.
• lubricants such as waxes and fillers, antifoaming agents, plasticizers, leveling agents, emulsifiers, dispersion stabilizers, surfactants, and tackifiers.
• Waxes include fatty acid amide wax, carnaval wax, polyolefin wax such as polyethylene wax and polypropylene wax, paraffin wax, Fischer-Tropsch wax, beeswax, microcrystalline wax, polyethylene oxide wax, amide wax and other waxes, coconut oil fatty acid and Soybean oil fatty acid and the like. These may be used alone or in combination. Thereby, blocking resistance can be improved. Polyethylene wax is preferably used because it can improve blocking resistance without deteriorating heat-sealing properties.
• the blending amount of wax can be adjusted as appropriate, but it is preferably 0.1 to 20% by mass of the thermoplastic resin. From the viewpoint of the balance between heat sealability and blocking resistance, the content is more preferably 3% by mass or more and 15% by mass or less.
• fillers examples include silica, calcium carbonate, calcium phosphate, talc, urethane beads, acrylic beads, melamine beads, etc., which can be used alone or in combination. It is preferred to use either silica or acrylic beads or both. Thereby, blocking resistance can be improved. Further, for example, when the laminate of the present invention is stored at high temperature, it is possible to prevent the heat seal layer from flowing out and reducing the film thickness.
• the shape of the filler is not particularly limited, but a spherical shape is preferable because it is less affected by deformation due to heat and a stable anti-blocking effect can be obtained regardless of how it is dispersed in the coating film.
• the average particle size of the filler is appropriately adjusted depending on the filler used, and is, for example, 0.5 to 10 ⁇ m.
• Antifoaming agents include fatty acid salts, higher alcohol sulfates, liquid fatty oil sulfates, sulfates of fatty amines and aliphatic amides, fatty alcohol phosphates, sulfonates of dibasic fatty acid esters, Fatty acid amide sulfonates, alkylallyl sulfonates, formalin condensation naphthalene sulfonates, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, polyoxyethylene sorbitan Examples include alkyl esters, acrylic polymers, silicone-mixed acrylic polymers, vinyl polymers, and polysiloxane compounds.
• the method of applying the heat sealing agent is not particularly limited, but examples include gravure coating, reverse coating, kiss coating, air knife coating, Meyer bar coating, roll coating, and dip coating.
• the heat-sealing layer may be provided on the entire surface of the laminate, or may be provided only on the portion to be heat-sealed during bag making.
• the heat sealing layer is formed by drying.
• the drying temperature is 50 to 180° C., and the drying time is about 0.5 seconds to 1 minute.
• the drying method is not particularly limited, but one example is hot air drying. If necessary, corona discharge treatment or the like may be applied as a post-treatment.
• the coating amount (solid content) of the heat sealing agent is not particularly limited, but is, for example, 1.0 to 15.0 g/m 2 . It is preferably 2.0 to 10.0 g/m 2 , more preferably 2.0 to 8.0 g/m 2 .
• the laminate of the present invention may have layers other than the paper substrate and the heat seal layer.
• One example is a print layer.
• the printed layer may be directly provided on the paper substrate, or a barrier layer or an anchor coat layer may be provided between the printed layer and the paper substrate.
• the printing layer is formed by a general printing method conventionally used for printing on paper substrates using various printing inks such as gravure ink, flexo ink, offset ink, stencil ink, and inkjet ink.
• an overcoat layer may be provided on the printed layer for the purpose of protecting the printed layer.
• Conventionally known coating agents can be suitably used for the overcoat layer. trademark) series, Sun Chemical's Vaporbloc series, and Sakata Inx's Brightone (registered trademark) series.
• Examples of the structure of the laminate in the case of having a printed layer and an overcoat layer include overcoat layer/printed layer/paper substrate/undercoat layer/gas barrier coat layer/heat seal layer, overcoat layer/printed layer/gas barrier coat. layer/undercoat layer/paper substrate/heat seal layer.
• the laminate of the present invention can be used as a multilayer packaging material for the purpose of protecting foods, medicines, and the like.
• the layer structure may vary depending on the contents, usage environment, and usage pattern.
• the packaging material of the present invention is obtained by bagging the laminate of the present invention and heat-sealing the peripheral edges.
• bag-making methods include side-sealing, two-side-sealing, three-side-sealing, four-side-sealing, envelope-sticking-sealing, joining-hands-sticking-sealing, pleated-sealing, flat-bottom-sealing, square-bottom-sealing, and gussets.
• a method of heat-sealing in a form such as a mold, other heat-sealing molds, or the like can be mentioned.
• the packaging material of the present invention can take various forms depending on the contents, environment of use, and form of use. A self-supporting packaging material (standing pouch) or the like is also possible.
• the portion to be heat-sealed may be provided with a heat-seal layer on both opposing surfaces, or may be provided on only one surface.
• heating method for heat sealing conventionally known means such as a heat source such as a burner, hot air, electric heat, infrared rays, and electron beams can be used.
• the heating temperature at this time is preferably 200 to 500° C., and the heating time is preferably 0.1 to 3 seconds.
• the heat seal layer After the heat seal layer is heated and softened, it is crimped.
• the crimping method is not particularly limited, and a hot plate method, ultrasonic sealing, or high-frequency sealing can be used.
• Paper base material 1 Daio Paper Co., Ltd., Nagoya Bleached Dragon King, basis weight 70 g/m 2
• Paper base material 2 manufactured by Oji Materia Co., Ltd., OK Blizzard, basis weight 70 g/m 2
• Paper base material 3 manufactured by Nippon Paper Industries Co., Ltd., capital wrap, basis weight 70 g/m 2
• Paper base material 4 manufactured by Nippon Paper Industries Co., Ltd., capital wrap, basis weight 80 g/m 2
• Paper base material 5 made by UPM, UPM Brilliant Pro, basis weight 62 g/m 2
• Paper base material 6 Oji Materia Co., Ltd., OK unbleached kraft paper, basis weight 100 g/m 2
• Aqueous coating agent 1 100 parts of isopropyl alcohol was charged into a four-necked flask purged with nitrogen gas, the temperature was raised to 80 to 82° C., and then 1 part of myristyl acrylate, 30 parts of styrene, 10 parts of acrylic acid, and 5 parts of methyl methacrylate were charged to the dropping funnel. A mixture of 1 part of benzoyl peroxide and 1 part of benzoyl peroxide was added dropwise over 2 hours. After the dropwise addition, 0.5 part of benzoyl peroxide was added, and the reaction was further continued for 2 hours.
• the temperature was lowered to 40° C., and dimethylethanolamine and ion-exchanged water were added. Thereafter, the temperature of the reaction flask was raised to 80-82° C. and stripping was carried out to finally obtain a water-soluble resin with a solid content of 30%.
• the acrylic emulsion thus obtained had a solid content of 40%, a minimum film-forming temperature of 1°C, a glass transition point of -27°C, and an acid value of 64 mgKOH/g of the solid content. This was used as the aqueous coating agent 1.
• Aqueous coating agent 2 CARBOSET GAW 7448 (manufactured by Lubrizol, water-based acrylic emulsion) was used as the water-based coating agent 2 .
• Solvent-based coating agent 1' Saias HR medium (manufactured by DIC, nitrocellulose resin solution) was used as the solvent-based coating agent 1'.
• solvent coating agent 2' Solbin M5 (manufactured by Nissin Chemical Industry Co., Ltd., vinyl chloride acetate resin) 100 parts by mass, Solbin A (manufactured by Nissin Chemical Industry Co., Ltd., vinyl chloride acetate resin) 5 parts by mass, PARALOID A-11 (DOW Inc., acrylic resin) dissolved in a mixed solvent of ethyl acetate and methyl ethyl ketone was used as the solvent-based coating agent 2'.
• Solbin M5 manufactured by Nissin Chemical Industry Co., Ltd., vinyl chloride acetate resin
• Solbin A manufactured by Nissin Chemical Industry Co., Ltd., vinyl chloride acetate resin
• PARALOID A-11 DOW Inc., acrylic resin
• solvent-based coating agent 3' Byron 500 (manufactured by Toyobo Co., Ltd., polyester resin) 50 parts by weight and 50 parts by weight of Elitel UE-3240 (manufactured by Unitika Ltd., polyester resin) are dissolved in a mixed solvent of ethyl acetate and methyl ethyl ketone. was used as the solvent-based coating agent 3'.
• Barrier coating agent 1 Gosenex Z-100 (manufactured by Mitsubishi Chemical Co., Ltd., modified polyvinyl alcohol resin) was dissolved in water so that the nonvolatile content was 10%, and ADH (manufactured by Otsuka Chemical Co., Ltd., adipic dihydrazide) ) was dissolved in a mixed solvent of water/IPA so that the non-volatile content was 5%.
• Barrier coating agent 2 Exeval AQ-4104 (manufactured by Kuraray Co., Ltd., modified polyvinyl alcohol resin) 50 parts by weight, Kunipia-F (manufactured by Kunimine Industries Co., Ltd., bentonite) 50 parts by weight, ethanol 20 parts by weight, water 80 parts by weight Mixed.
• a barrier coating agent 2 was used which was dispersed in a solvent so that the non-volatile content was 6%.
• Example 1 The water-based coating agent 1 was applied to the rough surface of the paper substrate 1 so that the solid content was 5.0 g/m 2 and dried in an oven at 80°C for 1 minute to form an undercoat layer.
• Barrier Coating Agent 1 was applied onto the undercoat layer so that the solid content was 0.8 g/m 2 and dried in an oven at 80° C. for 1 minute to form a barrier coat layer.
• Dickseal A-970NT manufactured by DIC Corporation, heat sealing agent
• Example 1 was carried out in the same manner as in Example 1, except that the paper base material, the water-based coating agent (or solvent-based coating agent) and its coating amount, and the barrier coating agent and its coating amount were changed as shown in Tables 1 and 2. 2 to 6 and Comparative Examples 1 to 5 were obtained.
• the laminate of the present invention exhibited good gas barrier properties.
• the gas barrier properties of Comparative Example 1 in which Ra1 is 5.0 ⁇ m or more, were inferior to those of the laminates of Examples.
• Comparative Examples 2 to 4 using solvent-based coating agents 1' to 3' instead of water-based coating agents, and Comparative Example 5 in which the undercoat layer was omitted did not reduce the Cobb water absorbency to a predetermined range, resulting in extremely poor It became inferior in gas barrier property.

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• 2022
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