Classifications

• • 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
  • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
  • D21H27/10—Packing paper
• • 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
  • D21H19/36—Coatings with pigments
  • D21H19/38—Coatings with pigments characterised by the pigments
• • 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
  • D21H19/36—Coatings with pigments
  • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
  • D21H19/56—Macromolecular organic compounds or oligomers thereof 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
  • D21H19/36—Coatings with pigments
  • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
  • D21H19/56—Macromolecular organic compounds or oligomers thereof obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H19/58—Polymers or oligomers of diolefins, aromatic vinyl monomers or unsaturated acids or derivatives thereof
• • 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
  • D21H19/36—Coatings with pigments
  • D21H19/44—Coatings with pigments characterised by the other ingredients, e.g. the binder or dispersing agent
  • D21H19/56—Macromolecular organic compounds or oligomers thereof obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H19/60—Polyalkenylalcohols; Polyalkenylethers; Polyalkenylesters
• • 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
• • 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
  • D21H19/822—Paper comprising more than one coating superposed two superposed coatings, both being pigmented
• • 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
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/50—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by form
  • D21H21/52—Additives of definite length or shape

Definitions

• the present invention relates to a paper barrier material used for food packaging materials or containers, cups and the like.
• gas barrier properties in particular, oxygen barrier properties
• Providing gas barrier properties (in particular, oxygen barrier properties) to paper packaging materials is important for protecting various products to be packaged from deterioration by gas, such as oxidation with oxygen.
• the paper-made packaging material which provided the gas-barrier property which laminated
• a material for forming the barrier layer a metal foil or a metal-deposited film made of a metal such as aluminum, a resin film such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinylidene chloride or polyacrylonitrile, or these resins are coated
• Patent Documents 1 and 2 disclose a paper gas barrier material having a gas barrier layer composed of a water-soluble polymer and an inorganic layered compound.
• Patent Document 2 discloses a paper gas barrier material provided with a barrier layer composed of a specific vinyl alcohol polymer on a covering layer.
• imparting water resistance (in particular, water vapor barrier property) to paper packaging materials is also important for protecting various products to be packaged from deterioration by water vapor. Paper with water vapor barrier property imparted by a method of extruding or laminating a resin film excellent in water vapor barrier property on a paper base material, or a film etc.
• Patent Document 3 discloses a packaging sheet having a moisture-proof layer made of synthetic resin latex, wax and inorganic fine particles. Furthermore, as a packaging material which gave both the gas barrier property and the water vapor barrier property to the paper packaging material, a packaging material obtained by laminating a resin having a gas barrier property and a resin having a water vapor barrier property on a paper substrate is known. .
• a packaging material in which both barrier layers are formed by extruding and laminating a resin having gas barrier properties and a resin having water vapor barrier properties on a paper base material (base paper) has limitations on the types of resins that can be extruded and laminated. There was a problem that it was impossible. Moreover, in order to make gas barrier property and water vapor barrier property make compatible, it is difficult to recycle paper and a laminate layer in the packaging material laminated in multiple layers to the paper base material. Multilayer laminated packaging materials also have the problem of increased CO 2 emissions in their manufacture. Furthermore, in the packaging material of a multilayer laminate, it may be necessary to use a specific adhesive resin between each laminate layer, and there is also a problem that the manufacture is complicated.
• a packaging material obtained by coating a paper substrate with a resin having gas barrier properties and a resin having water vapor barrier properties has few limitations such as the type of resin that can be used, and it becomes possible to cope with various required qualities.
• the moisture-proof layer of Patent Document 3 is provided on a packaging material having both gas barrier properties and water vapor barrier properties, for example, the packaging material having gas barrier properties of Patent Document 1 or Patent Document 2, good water vapor Although barrier properties can be obtained, there is a problem that gas barrier properties can not be obtained.
• the gas barrier layer of Patent Document 1 or Patent Document 2 is provided on the moistureproof paper having the moistureproof layer of Patent Document 3, the surface tension of the moistureproof layer is low, and the gas barrier layer is not uniformly formed by repelling. Gas barrier properties could not be obtained.
• an object of the present invention is to provide a paper barrier packaging material having both excellent gas barrier properties and water vapor barrier properties.
• the main configuration of the present invention is as follows. 1.
• the water vapor barrier layer and the gas barrier layer are coating agents of different compositions.
• the binder resin of the water vapor barrier layer is a styrene-butadiene based synthetic resin.
• the binder resin of the water vapor barrier layer is characterized by containing kaolin having an average particle diameter of 5 ⁇ m or more and an aspect ratio of 10 or more. Paper barrier packaging material as described in. 5.
• the water vapor barrier layer is characterized in that it contains a pigment having an average particle diameter of 5 ⁇ m or less. Paper barrier packaging material as described in. 6.
• the binder resin of the gas barrier layer is a polyvinyl alcohol resin. To 6. Paper barrier packaging material as described in. 8. 7.
• the gas barrier layer is characterized by containing kaolin having an average particle diameter of 5 ⁇ m or more and an aspect ratio of 10 or more. Paper barrier packaging material as described in.
• the coating agent for forming the gas barrier layer contains a crosslinking agent.
• Paper barrier packaging material as described in. 10. The paper according to 1., wherein the coating amount of the water vapor barrier layer is 4 to 30 g / m 2 on a dry weight basis, and the coating amount of the gas barrier layer is 0.2 to 10 g / m 2 on a dry weight basis Barrier packaging material.
• the barrier properties of both the water vapor barrier and the gas barrier can be realized by forming the water vapor barrier layer on the paper substrate and further forming the gas barrier layer thereon in this order.
• a paper barrier that exhibits excellent gas barrier properties and water vapor barrier properties by forming a water vapor barrier layer and a gas barrier layer by a coating agent coating layer using a polymer (water-based paint) using water as a dispersion medium as a binder Packaging material can be provided.
• the coating material for forming the gas barrier layer and the water vapor barrier layer is dried and solidified to be in the form of a film, and exhibits the function of blocking the permeation of water vapor and the permeation of gas (oxygen).
• the coating layer of the water-based paint has good compatibility with the layers, resistance to separation of the interface by water vapor or gas which easily penetrates from the other is strong, and both barrier functions can be maintained well.
• a barrier against water vapor or gas by forming one or both of a water vapor barrier layer and a gas barrier layer using a coating material to which kaolin having an average particle diameter of 5 ⁇ m or more and an aspect ratio of 10 or more is added as a large particle diameter pigment. Improves the quality.
• a coating agent to which a pigment having an average particle diameter of 5 ⁇ m or less is added the barrier property to water vapor or gas is improved.
• a styrene butadiene type synthetic resin is suitable as a polymer of the coating layer which forms a water vapor barrier layer.
• Polyvinyl alcohol resin is suitable as a polymer of the coating layer which forms a gas barrier layer.
• a combination of resins forming a coating layer containing polyvinyl alcohol resin as a main component on a coating layer containing styrene / butadiene synthetic resin as a main component on a paper base is excellent as a paper barrier packaging material.
• a styrene butadiene type synthetic resin or polyvinyl alcohol resin to which a crosslinking agent is added improves both barrier properties.
• a paper barrier packaging material (hereinafter sometimes referred to as "packaging material") in which a water vapor barrier layer and a gas barrier layer are provided in this order on a paper substrate (hereinafter sometimes referred to as "base paper"). It is.
• the two types of barrier layers are formed by applying an aqueous coating agent, and a pigment, a crosslinking agent and the like are mainly added to the polymer binder in the coating agent.
• the water vapor barrier layer or the gas barrier layer is formed by coating using a coating agent containing a polymer containing water as a dispersion medium as a binder resin.
• kaolin having an average particle diameter of 5 ⁇ m or more and an aspect ratio of 10 or more, a pigment having an average particle diameter of 5 ⁇ m or less, a crosslinking agent, or the like to the coating layer forming the two types of barrier layers.
• the paper barrier packaging material of the present invention in which a water vapor barrier layer is formed on a paper substrate and a gas barrier layer is formed thereon, has both excellent water vapor barrier properties and gas barrier properties is presumed as follows.
• a water-soluble polymer resin is used to form the gas barrier layer.
• moisture and the like in the air which permeates through the paper substrate act to degrade the gas barrier layer containing the water-soluble polymer.
• the paper barrier packaging material of the present invention has good water vapor barrier properties and gas barrier properties.
• the paper barrier packaging material of the present invention is generally used with the gas barrier layer side as the content (wrapped material) side and the paper layer side as the open air side (outside surface).
• the structure of the present invention is effective if the material to be packaged is a dry substance, since it is possible to prevent the penetration of moisture from the outside into the interior.
• an extrusion laminate layer of a resin or a laminate layer of a film is additionally formed on the inner gas barrier layer.
• the paper base is a sheet composed of pulp, filler and various auxiliary agents.
• the pulp is obtained from chemical pulp such as hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), sulfite pulp etc., mechanical grind such as stone grind pulp, thermomechanical pulp, kenaf, bamboo, hemp etc. Non-wood fiber etc. It is possible to use these materials appropriately blended.
• chemical pulps such as hardwood bleached kraft pulp (LBKP) and softwood bleached kraft pulp (NBKP) are preferable.
• Chemical pulp is less likely to be contaminated with foreign matter in the base paper, less likely to undergo discoloration over time when used as a waste paper raw material and used as a paper container, and has a high whiteness, so it has a surface during printing Suitable for reasons such as good feeling and high value of use as packaging material.
• filler known fillers such as white carbon, talc, kaolin, clay, ground calcium carbonate, light calcium carbonate, titanium oxide, zeolite, synthetic resin filler and the like can be used.
• internal additives for paper making such as sulfuric acid bands and various anionic, cationic, nonionic or amphoteric retention improvers, freeness improvers, paper strength improvers and internal sizing agents as needed It can be used.
• dyes, fluorescent whitening agents, pH adjusters, antifoaming agents, pitch control agents, slime control agents and the like can be added as necessary.
• the method for producing the paper substrate is not particularly limited, and it is possible to use the known long screen former, on-top hybrid former, gap former machine, acid paper making, neutral paper making, alkaline paper making Thus, a paper substrate can be produced.
• the paper base is preferably one having a basis weight of about 25 to 400 g / m 2 generally used for coated paper.
• the method of surface treatment of the paper substrate is not particularly limited, a known coating apparatus such as a rod metering size press, a pound size press, a gating oven, a spray coater, a blade coater, a curtain coater, etc. is used. be able to.
• a known coating apparatus such as a rod metering size press, a pound size press, a gating oven, a spray coater, a blade coater, a curtain coater, etc. is used. be able to.
• a resin which can use water as a dispersion medium is suitable.
• the dosage form includes the form of an aqueous polymer solution or an emulsion. This polymer corresponds to the binder of the coating material which forms a coating layer.
• the resin to be contained in the water vapor barrier layer various copolymers such as styrene / butadiene type, styrene / acrylic type, ethylene / vinyl acetate type, butadiene / methyl methacrylate type, vinyl acetate / butyl acrylate type, maleic anhydride copolymer It is possible to use a combination, an acrylic acid / methyl methacrylate copolymer, etc. singly or in combination of two or more. Among these, styrene-butadiene resins are preferable from the viewpoint of water vapor barrier properties.
• the styrene-butadiene based synthetic resin is obtained by emulsion polymerization of styrene and butadiene as main constituent monomers, in combination with various comonomers for the purpose of modification.
• the comonomer include methyl methacrylate, acrylonitrile, acrylamide, hydroxyethyl acrylate, and unsaturated carboxylic acids such as itaconic acid, maleic acid and acrylic acid.
• the resin uses water as a dispersant and is used as an emulsified emulsion-type coating agent.
• the emulsifier is an anionic surfactant such as sodium oleate, rosin acid soap, sodium alkylaryl sulfonate, sodium dialkyl sulfosuccinate and the like. These can be used alone or in combination with a nonionic surfactant. Furthermore, if necessary, amphoteric or cationic surfactants may be used.
• the coating material for forming the water vapor barrier layer preferably does not contain a water repellent component such as hydrocarbon, silicone resin, fluorine resin, fatty acid and ester of fatty acid and alcohol.
• the packaging material which has the conventional water-vapor-barrier property is provided with resin containing a water-repellent component. The water repellent component lowers the affinity between the water vapor barrier layer and the gas barrier layer, and the water or gas permeated from one layer promotes interfacial peeling, which is not preferable.
• the pigments include inorganic pigments and organic pigments.
• Inorganic pigments include kaolin, clay, engineered kaolin, delaminated clay, calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silica, silicate, colloidal silica, satin white Etc.
• the organic pigment is a solid-solid type, a hollow type, or a core-shell type. These pigments can be used alone or in combination of two or more.
• the pigment is suitably flat and large. Further, the combined use of the large particle size and the small particle size improves the water vapor barrier property.
• inorganic pigments such as kaolin having a flat shape improve the barrier property of water vapor.
• kaolin having an average particle diameter of 5 ⁇ m or more and an aspect ratio of 10 or more is more preferable.
• the flat pigment is distributed in parallel to the coating layer, and the water vapor that has penetrated into the water vapor barrier layer is blocked from moving in the thickness direction by the flat pigment and is diverted to move, and the water vapor is a water vapor barrier The path through the layer is lengthened and barrier properties are improved.
• the aspect ratio of the pigment to be added is small, the number of times water vapor bypasses in the coating layer is reduced, and the distance of movement is shortened. As a result, the water vapor barrier property is inferior to flat and large particle size pigments. Become.
• the flat pigment can be expected to have the same function even in the gas barrier layer.
• the dispersion of mica and montmorillonite has a lower concentration than the dispersion of kaolin, and the coating solution for a water vapor barrier layer using mica and montmorillonite has a low concentration, the dispersion is formed in the water vapor barrier layer to be formed. Because kaolin is difficult to orient, kaolin is more suitable.
• the water vapor barrier property can be further improved by further adding a pigment having an average particle diameter of 5 ⁇ m or less to the water vapor barrier layer in addition to the flat pigment addition described above.
• the small particle size pigment need not be flat.
• a pigment having an average particle diameter of 5 ⁇ m or less is further added to a water vapor barrier layer containing kaolin having an average particle diameter of 5 ⁇ m or more and an aspect ratio of 10 or more from the viewpoint of improvement of water vapor barrier properties and adhesion to a gas barrier layer. It is preferable to contain it.
• a pigment having an average particle diameter of 5 ⁇ m or less enters between kaolins having an average particle diameter of 5 ⁇ m or more and an aspect ratio of 10 or more, and water vapor forced to move along the flat kaolin surface is The small pigment particles will block migration. That is, when the water vapor barrier layer contains pigments having different flatness and average particle diameter, the pigment of small particle diameter is formed in the voids formed between the adjacent flat large particle diameter pigments in the water vapor barrier layer. In the state of being filled, the water vapor bypasses the pigment and passes it, so it exhibits high water vapor barrier properties as compared with the water vapor barrier layer not containing the pigment of small particle diameter.
• the blending ratio of kaolin having an average particle diameter of 5 ⁇ m or more and an aspect ratio of 10 or more and a pigment having an average particle diameter of 5 ⁇ m or less is preferably 50/50 to 99/1 on a dry weight basis. If the ratio of kaolin having an average particle diameter of 5 ⁇ m or more and an aspect ratio of 10 or more is smaller than the above range, the distance for water vapor to bypass in the coating layer becomes short, and sufficient water vapor barrier properties can not be obtained. On the other hand, when the content is more than the above range, the voids formed by the large particle diameter pigment in the coating layer can not be sufficiently filled with the pigment having an average particle diameter of 5 ⁇ m or less, and thus the water vapor barrier property is not improved.
• pigments having an average particle size of 5 ⁇ m or less as pigments having an average particle size of 5 ⁇ m or less, kaolin, clay, engineered kaolin, delaminated clay, ground calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid Inorganic pigments such as silicate, colloidal silica and satin white and organic pigments such as solid type, hollow type or core-shell type can be used singly or in combination of two or more. Among these pigments, ground calcium carbonate is preferred.
• the blending amount of the resin and the pigment is preferably in the range of 5 to 200 parts by weight of the resin (dry weight) with respect to 100 parts by weight of the pigment (dry weight). More preferably, it is 20 to 150 parts by weight of resin.
• various commonly used auxiliary agents such as dispersants, thickeners, water retention agents, antifoaming agents, water resistance agents, dyes, fluorescent dyes, etc. may be used. it can.
• Crosslinking agent In the present invention, it is preferable to add a crosslinking agent represented by a polyvalent metal salt or the like to the water vapor barrier layer.
• the crosslinking agent causes a crosslinking reaction with the binder contained in the water vapor barrier layer, thereby increasing the number of bonds (crosslinking point) in the water vapor barrier layer. That is, the water vapor barrier layer has a dense structure, and exhibits good water vapor barrier properties.
• the kind of the crosslinking agent is not particularly limited, and a polyvalent metal salt (copper, zinc, silver, iron, potassium, sodium, zirconium) according to the kind of the binder contained in the water vapor barrier layer
• a polyvalent metal such as aluminum, calcium, barium, magnesium, titanium, etc. and an ionic substance such as carbonate ion, sulfate ion, nitrate ion, phosphate ion, silicate ion, nitrogen oxide, boron oxide etc.
• An amine compound, an amide compound, an aldehyde compound, a hydroxy acid and the like can be appropriately selected and used.
• the number of blending parts of the crosslinking agent can be blended without being particularly limited as long as it is within the range of the paint concentration and the paint viscosity which can be applied.
• polyvalent metal salts should be used from the viewpoint of the crosslinking effect. Is preferred.
• potassium alum is more preferred.
• the addition amount of the crosslinking agent is 1 to 10 parts by weight with respect to 100 parts by weight of the binder resin used for the water vapor barrier layer. More preferably, it is 3 to 5 parts by weight. If the amount is less than 1 part by weight, a sufficient effect can not be obtained, and if the amount is more than 10 parts by weight, the viscosity of the coating liquid significantly increases, which makes coating difficult.
• a crosslinking agent when added to a coating liquid for forming a water vapor barrier layer, it is preferable to dissolve the crosslinking agent in a polar solvent such as an ammonium hydroxide solution and then add it to the coating liquid.
• a polar solvent such as an ammonium hydroxide solution
• the crosslinking reaction with the polar solvent does not occur immediately even if it is incorporated in the coating liquid, so that the crosslinking reaction with the latex does not occur, and the thickening of the coating can be suppressed.
• the polar solvent component is volatilized by drying after coating on paper, a crosslinking reaction with the binder occurs, and a dense water vapor barrier layer is formed.
• the contact angle with water of the surface of the water vapor barrier layer provided on the paper substrate is preferably less than 90 °, more preferably less than 85 °, still more preferably less than 80 °.
• the contact angle with water is 90 ° or more, it becomes difficult to provide a uniform gas barrier layer on the water vapor barrier layer, and it becomes difficult to exhibit high gas barrier properties. If the angle is less than 90 °, the repulsion between the water vapor barrier layer and the gas barrier layer can be suppressed to suppress peeling between the two layers.
• the contact angle is a standard for estimating the affinity between the water vapor barrier layer and the gas barrier layer.
• the method of adjusting the contact angle with water on the surface of the water vapor barrier layer is not limited, but mention may be made of the use of a resin for water vapor barrier layer with a low contact angle with water, addition of a pigment, etc. Can.
• the water-soluble polymer used as a binder resin of a coating material for forming a gas barrier layer completely saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, ethylene copolymerized polyvinyl alcohol, polyvinyl pyrrolidone, starch, methyl cellulose, Carboxymethylcellulose, sodium alginate and the like can be exemplified.
• polyvinyl alcohol and carboxymethyl cellulose are preferable, and polyvinyl alcohol is more preferable, from the viewpoint of gas barrier properties.
• pigments used for the gas barrier layer kaolin, clay, engineered kaolin, layered clay, calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid
• inorganic pigments such as silicate, colloidal silica, satin white and mica, and organic pigments such as solid, hollow or core-shell type. These can be used singly or in combination of two or more. Among these, it is preferable to use an inorganic pigment in terms of gas barrier properties.
• an inorganic pigment especially kaolin
• an inorganic pigment especially kaolin
• an inorganic pigment especially kaolin
• an inorganic pigment especially kaolin
• an inorganic pigment especially kaolin
• an average particle diameter of 5 ⁇ m or more and an aspect ratio of 50 or more is particularly preferred.
• a gas such as oxygen bypasses the pigment and passes through.
• the gas barrier layer which consists of a water-soluble polymer which does not contain a pigment, it has the outstanding gas-barrier property in the favorable water vapor barrier property and high humidity atmosphere.
• the blending ratio (dry weight) of the pigment to the water-soluble polymer contained in the gas barrier layer is preferably 1/100 to 1000/100 of the pigment / water-soluble polymer. If the proportion of the pigment is outside the above range, sufficient gas barrier properties will not be exhibited.
• a crosslinking agent represented by a polyvalent metal salt or the like
• the crosslinking agent combines the hydroxyl groups of the water-soluble polymer with a crosslinking structure, so that the amount of hydroxyl groups which loose (or break) the bond when high humidity is reduced and the water resistance of the whole layer is improved. It is possible to suppress the decrease in oxygen barrier properties under humidity.
• the kind of the crosslinking agent is not particularly limited, and a polyvalent metal salt (copper, zinc, silver, iron, potassium, sodium, zirconium) according to the kind of the binder contained in the water vapor barrier layer
• a polyvalent metal such as aluminum, calcium, barium, magnesium, titanium, etc. and an ionic substance such as carbonate ion, sulfate ion, nitrate ion, phosphate ion, silicate ion, nitrogen oxide, boron oxide etc.
• An amine compound, an amide compound, an aldehyde compound, a hydroxy acid and the like can be appropriately selected and used.
• blending part number of a crosslinking agent if it is in the range of the coating concentration which can be apply
• polyvalent metal salts should be used from the viewpoint of the crosslinking effect. Is preferred, and potassium alum is more preferred.
• the addition amount of the crosslinking agent is 1 to 10 parts by weight, more preferably 3 to 5 parts by weight with respect to 100 parts by weight of the resin used for the gas barrier layer. If the amount is less than 1 part by weight, a sufficient effect can not be obtained, and if the amount is more than 10 parts by weight, the viscosity of the coating liquid significantly increases, which makes coating difficult.
• the gas barrier layer may contain, in addition to water-soluble polymers and pigments, various commonly used auxiliary agents such as dispersants, thickeners, water retention agents, antifoaming agents, water resistance agents, dyes and fluorescent dyes. It can be used.
• the coating method of the water vapor barrier layer and the gas barrier layer is not particularly limited, and a known coating apparatus can be used.
• a blade coater, a bar coater, a roll coater, an air knife coater, a reverse roll coater, a curtain coater, a spray coater, a size press coater, a gate roll coater and the like can be mentioned.
• a method of drying a coating layer normal methods, such as a vapor heating heater, a gas heater, an infrared heater, an electric heater, a hot-air heater, a microwave, a cylinder drier, are used, for example.
• the coating amount of the water vapor barrier layer is preferably 4 to 30 g / m 2 , more preferably 6 to 25 g / m 2 , and still more preferably 10 to 20 g / m 2 in dry weight. Is preferred. If the coating amount is 3 g / m 2 or less, it becomes difficult for the coating solution to completely cover the base paper, and sufficient water vapor barrier properties can not be obtained. There is a problem that gas barrier properties can not be obtained. On the other hand, when it is 30 g / m 2 or more, the drying load at the time of coating becomes large, which is not preferable from both the viewpoint of operation and cost.
• the coating amount of the gas barrier layer is preferably 0.2 to 10 g / m 2 on a dry weight basis. If the coating amount is less than 0.2 / m 2 , a uniform gas barrier layer can not be formed, so there is a problem that sufficient gas barrier properties can not be obtained. On the other hand, when it is 10 g / m 2 or more, the drying load at the time of coating becomes large, which is not preferable from both the viewpoint of operation and cost.
• a sealant layer of polyethylene, polypropylene, polyvinyl acetate polymer or the like can be provided on a paper barrier packaging material provided with a water vapor barrier layer and a gas barrier layer on a paper substrate.
• the method for laminating the sealant layer is not particularly limited, and known methods such as a conventional melt extrusion lamination method, a dry lamination method using a film, a direct melt coating method and the like can be used.
• Water vapor transmission rate Measured using a moisture permeability measuring device (L80-4000 manufactured by Dr. Lyssy) under the conditions of a temperature of 40 ⁇ 0.5 ° C. and a relative humidity of 90 ⁇ 2%.
• Oxygen permeability Measured under conditions of 23 ° C., 0% RH and 23 ° C., 85% RH, using OX-TRAN 2/21 manufactured by MOCON.
• Contact angle in an atmosphere of 23 ° C. and 50% RH, using a dynamic surface contact angle measurement device (Dynamic Absorption Tester DAT1100 manufactured by Fibro), the surface contact angle after 0.1 seconds after dropping a water droplet Was measured.
• Average particle size The sample slurry is mixed dropwise in pure water to which 0.2% by weight of dispersant hexametaphosphate sodium is added to obtain a uniform dispersion, and a laser method particle size measuring apparatus (equipment: Mastersizer manufactured by Malvern Co., Ltd. Particle size measurement using S type).
• Example 1 (Preparation of paper base) A Canadian standard freeness (CSF) 500 ml of hardwood kraft pulp (LBKP) and CSF 530 ml of softwood kraft pulp (NBKP) were blended at a weight ratio of 80/20 to make a raw material pulp.
• the raw material pulp slurry contains, as a dry strength agent, polyacrylamide (PAM) having a molecular weight of 2.5 million per 100% by weight of bone dry pulp, and 0.1% by weight of alkyl ketene dimer (AKD) as a sizing agent.
• PAM polyacrylamide
• ALD alkyl ketene dimer
• polyvinyl alcohol (PVA 117 manufactured by Kuraray Co., Ltd.) prepared to a solid content concentration of 2% is applied to both sides of the obtained paper by 1.0 g / m 2 coating on both sides using a rod metalling size press, and dried. I got 2 base papers.
• the obtained base paper was smoothed using a chilled calender at a speed of 300 min / m, a linear pressure of 50 kgf / cm, and one pass.
• a polyvinyl alcohol (PVA 117 manufactured by Kuraray Co., Ltd.) was prepared to have a solid content concentration of 10%, to obtain a coating solution B.
• the coating solution A was coated on one side using a blade coater at a coating speed of 300 m / min so as to give a coating amount (dry) of 12 g / m 2 on the obtained base paper, and then dried.
• B was coated on one side using a roll coater at a coating speed of 300 m / min to a coating amount (dry) of 2.0 g / m 2 to obtain a paper barrier packaging material.
• Example 3 Dissolve potassium alum (potassium aluminum sulfate 12 hydrate by Kanto Chemical Co., Ltd.) in the coating solution for oxygen barrier layer to a concentration of 5%, and use the obtained aqueous solution of potassium alum as a solid content against polyvinyl alcohol
• a paper barrier packaging material was obtained in the same manner as in Example 1 except that it was blended to be 3 parts and a coating liquid having a solid content concentration of 10% was used.
• a potassium alum aqueous solution is mixed so that the solid content is 3 parts with respect to polyvinyl alcohol and a coating liquid having a solid content concentration of 10% is used.
• Example 5 Heavy calcium carbonate slurry (FMT-75, manufactured by Fimatech Co., Ltd., FMT-75, average particle size: 1.6 ⁇ m, aspect ratio: 1) in the pigment composition ratio of the pigment of the coating liquid A in the coating liquid for water vapor barrier layer A paper barrier packaging material was obtained in the same manner as in Example 1 except that the coating liquid was mixed and stirred so as to be 25:25.
• Example 6 The coating solution for water vapor barrier layer was mixed with the aqueous solution of potassium alum dissolved in Example 3 in the coating solution obtained in Example 5 so as to be 3 parts of a pigment, and the coating with a solid content concentration of 50% was applied.
• a paper barrier packaging material was obtained in the same manner as in Example 1 except that the working fluid was used.
• Example 7 Example 1 except using the coating liquid obtained in Example 5 using the coating liquid obtained in Example 4 in the coating liquid for oxygen barrier layer A paper barrier packaging material was obtained in the same manner as in.
• Example 8 Example 1 except using the coating liquid obtained in Example 6 using the coating liquid obtained in Example 4 in the coating liquid for oxygen barrier layer A paper barrier packaging material was obtained in the same manner as in.
• Example 9 Example except that the large particle size engineered kaolin in the coating liquid obtained in Example 2 was changed to mica (B-82 particle size: 180 ⁇ m manufactured by Matsuo Sangyo Co., Ltd.) in the coating liquid for oxygen barrier layer A paper barrier packaging material was obtained in the same manner as 2).
• Example 10 Except that the large particle size engineered kaoline in the coating liquid obtained in Example 1 was changed to montmorillonite (Nikkanite A-36 particle size: 400 ⁇ m manufactured by Toshin Kasei Co., Ltd.) in the coating liquid for oxygen barrier layer in the coating liquid for oxygen barrier layer A paper barrier packaging material was obtained in the same manner as in Example 1.
• montmorillonite Nakkanite A-36 particle size: 400 ⁇ m manufactured by Toshin Kasei Co., Ltd.
• Example 11 In the coating solution for water vapor barrier layer, the large particle size engineered kaolin in the coating solution obtained in Example 1 is changed to mica (B-82 particle size: 180 ⁇ m manufactured by Matsuo Sangyo Co., Ltd.), and the pigment dispersion concentration is changed.
• a paper barrier packaging material was obtained in the same manner as in Example 1 except that the concentration of the coating liquid was changed to 20% and the concentration of the coating liquid was changed to 30.
• Example 12 In the coating solution for water vapor barrier layer, the large particle size engineered kaolin in the coating solution obtained in Example 1 is changed to montmorillonite (Nikkanite A-36 particle size: 400 ⁇ m manufactured by Toshin Kasei Co., Ltd.), A paper barrier packaging material was obtained in the same manner as in Example 1 except that the pigment dispersion concentration was changed to 20%, the coating liquid concentration to 30%, and the coating amount to 9 g / m 2 .
• montmorillonite Nakkanite A-36 particle size: 400 ⁇ m manufactured by Toshin Kasei Co., Ltd.
• Example 13 A paper was prepared in the same manner as in Example 1 except that the styrene butadiene latex of Example 1 was changed to an acrylic styrene copolymer emulsion (Cybinol X-511-374E manufactured by Siden Chemical Co., Ltd.) in the coating liquid for water vapor barrier layer. Obtained barrier packaging material.
• Example 14 A paper barrier packaging material was obtained in the same manner as in Example 1 except that the coating solution for a water vapor barrier layer was changed to a styrene butadiene latex (L7360 manufactured by Asahi Kasei Chemicals Corporation).
• the pigment used in the coating solution is made from large particle size engineered kaolin (Varisurf HX manufactured by Imeris Co., Ltd.) large particle size engineered Kaoline (Capim CC manufactured by Imeris Co., Ltd., particle size: 8.0 ⁇ m)
• a paper barrier packaging material was obtained in the same manner as in Example 1 except that the aspect ratio was changed to 10 to 15).
• the pigment used in the coating solution is made from large particle size engineered kaolin (Varisurf HX manufactured by Imeris) to fine particle kaolin (manufactured by KaMin, Hydragloss, average particle size: 0.3 ⁇ m, aspect ratio)
• KaMin large particle size engineered kaolin
• Hydragloss fine particle kaolin
• a paper barrier packaging material was obtained in the same manner as in Example 1 except that it was changed to 10-15).
• the pigment used in the coating solution is made from large particle size engineered kaolin (Varisurf HX manufactured by Imeris Co., Ltd.) to second grade kaolin (KCS manufactured by Imeris Co., Ltd., average particle size: 3.6 ⁇ m, aspect ratio
• a paper barrier packaging material was obtained in the same manner as in Example 1 except that it was changed to 10-15).
• Example 18 A paper barrier packaging material was obtained in the same manner as in Example 1 except that the latex used in the coating liquid in the coating liquid for a water vapor barrier layer was changed to a styrene butadiene latex (PNT7889 manufactured by Nippon Zeon Co., Ltd.).
• Example 19 A paper barrier packaging material was obtained in the same manner as in Example 1 except that the latex used in the coating liquid in the coating liquid for a water vapor barrier layer was changed to a styrene butadiene latex (L7360 manufactured by Asahi Kasei Chemicals Corporation).
• Example 20 A paper barrier packaging material was obtained in the same manner as in Example 1 except that the latex used in the coating liquid in the coating liquid for a water vapor barrier layer was changed to an acrylic copolymer latex (E316 manufactured by Asahi Kasei Chemicals Corporation). .
• Example 21 A paper barrier packaging material was prepared in the same manner as in Example 1 except that the latex used in the coating liquid in the coating liquid for a water vapor barrier layer was changed to an acrylic copolymer aqueous emulsion (EK-61 manufactured by Siden Chemical Co., Ltd.). Obtained.
• Example 22 The coating amount of the coating liquid A, except for changing from 12 g / m 2 to 6 g / m 2 in dry weight in the same manner as in Example 1 to obtain a paper barrier packaging materials.
• Example 23 To coverage of the coating liquid A, except for changing from 12 g / m 2 to 15 g / m 2 in dry weight in the same manner as in Example 1 to obtain a paper barrier packaging materials.
• Example 24 The coating amount of the coating liquid B, and dry weight of 2 g / m 2 was changed to 1 g / m 2 in the same manner as in Example 1 to obtain a paper barrier packaging materials.
• Example 25 The coating amount of the coating liquid B, and dry weight of 2 g / m 2 was changed to 4g / m 2 in the same manner as in Example 1 to obtain a paper barrier packaging materials.
• Example 26 The same procedure as in Example 1 was repeated except that the blending amount of the styrene butadiene latex (PNT 7868 manufactured by Nippon Zeon Co., Ltd.) was changed from 100 parts to 50 parts of the pigment (solid content) in the preparation of the coating liquid for water vapor barrier layer A paper barrier packaging material was obtained.
• PNT 7868 manufactured by Nippon Zeon Co., Ltd.
• Example 27 The same procedure as in Example 1 was repeated except that the blending amount of the styrene butadiene latex (PNT 7868 manufactured by Nippon Zeon Co., Ltd.) was changed from 100 parts to 150 parts of pigment (solid content) in the preparation of the coating liquid for water vapor barrier layer A paper barrier packaging material was obtained.
• PNT 7868 manufactured by Nippon Zeon Co., Ltd.
• Comparative Example 1 A paper barrier packaging material was obtained in the same manner as in Example 1 except that a gas barrier layer and a water vapor barrier layer were provided in this order on the paper substrate.
• Comparative Example 2 A paper barrier packaging material was obtained in the same manner as in Example 1 except that the water vapor barrier layer was not provided.
• Comparative Example 3 A paper barrier packaging material was obtained in the same manner as in Example 1 except that the gas barrier layer was not provided.
• Example 1 From the data of Example 1, Comparative Examples 1, 2 and 3, Example 1 in which a water vapor barrier layer was formed on a paper substrate and a gas barrier layer was further formed thereon, the water vapor permeability, oxygen permeation The degree is also low.
• Comparative Example 2 in which only the gas barrier layer is provided is Comparative Example 3 in which only the water vapor barrier layer is provided, in which the oxygen permeability and the water vapor permeability are very large and neither barrier function is exhibited.
• Example 1 In Comparative Example 1 in which the water vapor barrier layer is provided on the gas barrier layer, the water vapor barrier property exhibits the same function as in Example 1, but the gas barrier property is not observed at all. This shows the result that the moisture which permeated the paper base material deteriorated the gas barrier layer. Accordingly, the results clearly show the usefulness of the present invention in which the water vapor barrier layer is provided on the paper substrate and the gas barrier layer is formed thereon.
• Examples 6 and 8 in which potassium alum, which is a crosslinking agent, is added to the coating material for the water vapor barrier layer, the water vapor barrier properties are improved more than in Example 1.
• the gas barrier performance in a high humidity environment was also found to be similarly dependent on the particle size.
• styrene-butadiene-based and acrylic-based polymers are useful as a binder resin used for a coating material for forming a water vapor barrier layer It could be confirmed.
• the coating amount (dry weight) of the water vapor barrier layer is 6 to 15 g / m 2
• the coating amount (dry weight) of the gas barrier layer is 1 to 4 g / m 2. It has been confirmed that it exerts its character.

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• 2012
  • 2012-11-09 EP EP12847115.8A patent/EP2777934B1/en active Active
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