Barrier Paper

Abstract

PURPOSE: To provide an environment consideration type barrier paper which is excellent in oxygen barrier property and water vapor barrier property, and interlayer adhesion before and after bending or before and after bag making, and is reduced in a used amount of an organic solvent, and an environment consideration type gas barrier paper-based laminate, bas barrier paper-based material and gas barrier paper-based package which are made of the environment consideration type barrier paper.SOLUTION: Barrier paper has such layer constitution that at least fixation filler layers contacting a paper base material layer, and gas barrier layers contacting the fixation filler layers are laminated on both sides of the paper base material layer, wherein the fixation filler layer contains one or two or more kinds selected from the group consisting of a polystyrene-based resin, a polyurethane-based resin and an acrylic resin, the fixation filler layers on both of the sides have the same or different compositions, the gas barrier layer contains a polyurethane-based resin and / or a polyvinyl alcohol-based resin, the gas barrier layers on both of the sides have the same or different compositions, and the gas barrier layer on at least one surface further contains an inorganic filler.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a barrier paper having excellent oxygen barrier properties, water vapor barrier properties and interlayer adhesion, and to a gas barrier paper-based laminate, a gas barrier paper-based material and a gas barrier paper-based packaging product made from said barrier paper. [Background technology]

[0002] In recent years, environmental issues such as microplastics have been receiving a lot of attention, and in order to reduce the environmental impact of paper-based products, there is now a demand to improve recyclability by making products out of paper as much as possible, and even to consider biodegradability. Conventional packaging methods for preventing deterioration of the contents of foods, medical products, chemical products, cosmetics, etc. due to moisture and oxygen have included the use of packaging materials with high gas barrier properties, gas replacement of the content storage section with an inert gas such as nitrogen gas, and the inclusion of an oxygen absorber packaged with reduced iron powder or the like. However, there are problems such as insufficient performance, increased packaging costs, increased garbage as waste, only functioning in moist environments, and the risk of accidental ingestion. When considering the recycling or incineration of used packaging materials, packaging materials using paper have begun to attract attention. However, paper alone does not have sufficient gas barrier properties. In order to improve gas barrier properties, the surface is coated with resin or a resin film having a metal foil or inorganic vapor deposition layer is laminated. This inhibits the recycling or biodegradation of the paper alone, causes damage to incinerators when burned, and generates large amounts of incineration residue due to the metal foil.

[0003] Patent Document 1 discloses a laminate in which a gas barrier thin film layer formed by plasma polymerization is laminated on a substrate made of paper or pulp mold having a surface with a filler layer made of a polycondensate of polysaccharide and silicon compound. However, in this laminate, the thickness of the filler layer needs to be increased to about several tens of μm, and the coating method of the filler layer is limited. Furthermore, in order to put a substrate made of paper or pulp mold into a plasma polymerization device when forming a gas barrier thin film layer, paper powder or pulp powder generated from the paper or pulp mold tends to prevent the inside of the plasma polymerization device from being reduced in pressure to a level suitable for plasma polymerization, making it difficult to form a stable gas barrier thin film layer, and the adhesion between the filler layer and the gas barrier thin film layer tends to be insufficient, resulting in a defect that the gas barrier property tends to be unstable.

[0004] Patent Document 2 discloses a gas barrier laminate in which a first gas barrier layer containing an ethylene-modified polyvinyl alcohol resin and an inorganic layered compound and a second gas barrier layer made of ethylene-modified polyvinyl alcohol are sequentially provided on a paper support. However, it has been difficult to meet various quality requirements due to insufficient interlayer adhesion between the paper support and the first gas barrier layer and limitations on the types of resins used in the first and second gas barrier layers. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4622201 [Patent Document 2] Patent Publication 2009-184138 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention solves the above problems and improves the oxygen barrier property and water resistance before and after bending or before and after bag making. The objective of the present invention is to provide an environmentally friendly barrier paper that has excellent vapor barrier properties and interlayer adhesion and reduces the amount of organic solvent used, and to provide an environmentally friendly gas barrier paper-based laminate, a gas barrier paper-based material, and a gas barrier paper-based packaging product made from the environmentally friendly barrier paper. [Means for solving the problem]

[0007] As a result of various studies, the inventors have found that the above-mentioned object can be achieved by a barrier paper having a layer structure in which a specific fixed filling layer and a specific gas barrier layer are laminated adjacently in this order on at least both sides of a paper base layer.

[0008] The present invention is characterized in the following points. 1. A laminate structure in which at least a fixed filling layer in contact with the paper base layer and a gas barrier layer in contact with the fixed filling layer are laminated on both sides of a paper base layer, The fixing filling layer contains one or more resins selected from the group consisting of polystyrene-based resins, polyurethane-based resins, and acrylic-based resins, The fixed sealing layers on both sides have the same or different compositions, the gas barrier layer contains a polyurethane resin and / or a polyvinyl alcohol resin, The gas barrier layers on both sides have the same or different compositions; 13. A barrier paper, wherein the gas barrier layer on at least one side further contains an inorganic filler. 2. The barrier paper described in 1 above, wherein the fixed sealing layer on at least one side further contains an inorganic filler. 3. The barrier paper according to 1 or 2 above, wherein the fixed sealing layer on at least one side contains a polyurethane-based resin. 4. The barrier paper according to any one of 1 to 3 above, wherein the gas barrier layers on both sides each further contain an inorganic filler. 5. Oxygen permeability at 23℃ and 0% humidity according to JIS K7126 is 0.01cc / m 2 / day / atm or more, 20cc / m2 5. The barrier paper according to any one of 1 to 4 above, characterized in that the thermal conductivity is 1 / day / atm or less. 6.Water vapor permeability at 40℃ and 90% humidity according to JIS K7129 is 0.01g / m 2 / daym or more, 30g / m 2 6. The barrier paper according to any one of 1 to 5 above, characterized in that the drying time is 10 hours / day or less. 7. After folding the sheet in half at 180 degrees and stretching it, the oxygen permeability at 23°C and 0% humidity according to JIS K7126 is 0.1cc / m 2 / day / atm or more, 100cc / m 2 7. The barrier paper according to any one of 1 to 6 above, characterized in that the thermal conductivity is 1 / day / atm or less. 8. After folding the sheet in half at 180 degrees and stretching it, the water vapor permeability at a temperature of 40°C and humidity of 90% conforming to JIS K7129 is 0.1g / m 2 / day or more, 40g / m 2 8. The barrier paper according to any one of 1 to 7 above, characterized in that the drying time is 100 minutes / day or less. 9. A gas barrier paper laminate having oxygen barrier properties and water vapor barrier properties, produced using the barrier paper described in any one of 1 to 8 above. 10. A gas barrier paper material having oxygen barrier properties and water vapor barrier properties, produced using the gas barrier paper laminate described in 9 above. 11. A gas barrier paper-based packaging body having oxygen barrier properties and water vapor barrier properties, produced using the gas barrier paper-based material described in 10 above. Effect of the Invention

[0009] According to the present invention, there is provided an environmentally friendly barrier paper that has excellent oxygen barrier properties, water vapor barrier properties, and interlayer adhesion before and after bending or before and after bag making, and in which the amount of organic solvent used is reduced. It is possible to obtain environmentally friendly gas barrier paper-based laminates, gas barrier paper-based materials, and gas barrier paper-based packaging products made from this type of barrier paper. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of a barrier paper of the present invention. [Diagram 2] FIG. 1 is a schematic cross-sectional view showing an example of the layer structure of a gas barrier paper material of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The environmentally friendly barrier paper, gas barrier paper-based laminate, gas barrier paper-based material, and gas barrier paper-based packaging body of the present invention will be described in detail below with reference to the drawings.

[0012] The resin names used in the present invention are those commonly used in the industry. Furthermore, the present invention is not limited to the specific examples listed below. In the present invention, films and sheets are collectively referred to as films. In the present invention, the term "gas barrier property" refers to oxygen barrier property and water vapor gas barrier property.

[0013] <Barrier paper> The barrier paper of the present invention has oxygen barrier properties and water vapor barrier properties before and after bending or before and after bag making, and is an environmentally friendly barrier paper in which the amount of organic solvents used during production is reduced. Here, the bending treatment refers to an alternative treatment that imparts the bending load that packaging materials receive during bag production. For quantitative evaluation, the bending treatment can be, for example, a process in which the barrier paper is folded in half at 180 degrees (mountain fold) so that the paper layer is on the outside, and then stretched and returned to its original state. The barrier paper of the present invention has a layer structure in which at least a fixed filling layer and a gas barrier layer are laminated adjacent to each other in this order on both sides of a paper base layer. The gas barrier layer is a layer that imparts oxygen barrier property and water vapor barrier property, and the fixing filling layer is a layer that fills the paper base layer, fixes the gas barrier layer between the gas barrier layer and the paper base layer, improves adhesion, and supports the oxygen barrier property and water vapor barrier property. The high adhesion can prevent deterioration of the oxygen barrier property and water vapor barrier property due to internal peeling.

[0014] In the barrier paper, the fixed sealing layer and the gas barrier layer are laminated on both sides of the paper base layer. By laminating them on both sides, the functional load of the fixed sealing layer and the gas barrier layer on each side can be reduced, and a wider range of composition and thickness can be provided than when they are laminated only on one side, making it possible to achieve a wide range of balance such as a reduced number of constituent layers, a reduced thickness, high productivity, and suppression of high rigidity of the barrier paper, thereby improving usability in packaging material applications. The fixing filling layers on both sides may have the same composition or different compositions, and the gas barrier layers on both sides may have the same composition or different compositions.

[0015] The thickness of the barrier paper of the present invention is not particularly limited, but is preferably 20 μm or more and 250 μm or less, and more preferably 30 μm or more and 120 μm or less. If it is thinner than the above range, it is likely to be difficult to form a fixed sealing layer and a gas barrier layer of sufficient thickness, and there is a risk that the rigidity of the packaging material will be insufficient when used in the packaging material. If it is thicker than the above range, there is a risk that the rigidity of the packaging material will be too strong when used in the packaging material.

[0016] The thickness or basis weight of the paper base layer is not particularly limited, but the thickness is preferably 20 μm or more and 200 μm or less, and more preferably 30 μm or more and 100 μm or less. The basis weight is 25 g / m 2 More than 600g / m 2 Less than 50 g / m is preferable. 2 More than 450g / m 2 The following is more preferred If the basis weight and / or thickness is smaller than the above range, it will be difficult to achieve sufficient rigidity, and curling or waviness will be likely to occur during production of the barrier paper, whereas if it is larger than the above range, the rigidity will be too strong, making workability poor, and the winding diameter of the barrier paper will increase, which will likely reduce work efficiency, and the paper may be less suitable as a barrier paper. The thickness ratio of the paper base layer in the barrier paper of the present invention is not particularly limited, but is preferably from 80% to 99%, and more preferably from 90% to 98%. If it is lower than the above range, the recyclability and biodegradability efficiency of the barrier paper is likely to decrease, and even if it is higher than the above range, the recyclability and biodegradability efficiency are unlikely to change any further, and sufficient oxygen barrier property and water vapor barrier property may not be exhibited.

[0017] The thickness or coating amount of the fixed filling layer is not particularly limited, but the thickness is preferably 0.2 μm or more and 25 μm or less, and more preferably 0.5 μm or more and 20 μm or less. The coating amount is 0.5 g / m 2 More than 30m 2 Less than 1 g / m is preferable. 2 More than 20m 2 If the thickness is thinner than the above range, it is likely to be difficult to fix the gas barrier layer with sufficient filling properties, and if the thickness is thicker than the above range, there is not much improvement in the filling properties and the effect of fixing the gas barrier layer. The thicknesses of the fixed filling layers on both sides of the paper base layer may be the same or different.

[0018] The thickness or coating amount of the gas barrier layer is not particularly limited, but the thickness is preferably 0.1 μm or more and 10 μm or less, and more preferably 0.2 μm or more and 5 μm or less. The coating amount is 0.3 g / m 2 More than 10m 2 Less than 0.5 g / m is preferred. 2 More than 5m 2 If the thickness is thinner than the above range, it is difficult to provide sufficient oxygen barrier property and water vapor barrier property, and if the thickness is thicker than the above range, the oxygen barrier property and water vapor barrier property are not significantly improved. The thickness of the gas barrier layers on both sides of the paper base layer may be the same or different.

[0019] The barrier paper of the present invention exhibits excellent oxygen barrier properties and water vapor barrier properties due to the synergistic effect of the fixing filling layer and the gas barrier layer. Furthermore, it is preferable that the barrier paper of the present invention maintains excellent oxygen barrier properties and water vapor barrier properties even after bending treatment. Furthermore, when the fixed filling layer and the gas barrier layer are present on both sides, the film is likely to exhibit better oxygen barrier property and water vapor barrier property than when they are present on only one side, and in particular, the oxygen barrier property and water vapor barrier property after bending treatment are likely to be better.

[0020] The oxygen barrier property and water vapor barrier property can be expressed by the oxygen permeability and water vapor permeability measured by methods in accordance with JIS K7126 and K7129, respectively. Before bending, the barrier paper had an oxygen permeability of 0.01cc / m at a temperature of 23°C and humidity of 0%. 2 / day / atm or more, 20cc / m 2 / day / atm or less is preferable, and 0.05cc / m 2 / day / atm or more, 10cc / m 2 It is more preferable that the oxygen barrier property is not more than 1 / day / atm.

[0021] For example, after folding in half at 180 degrees, the oxygen permeability at a temperature of 23°C and humidity of 0% is 0.1cc / m 2 / day / atm or more, 100cc / m 2 / day / atm or less is preferable, and 0.5cc / m 2 / day / atm or more, 50cc / m 2 It is more preferable that the oxygen barrier property is not more than 1 / day / atm.

[0022] Before bending, the barrier paper had a water vapor permeability of 0.01 at a temperature of 40°C and a humidity of 90%. g / m 2 / day or more, 30g / m 2 / day or less, and 0.05 g / m 2 / day or more, 20g / m 2 It is more preferable that the film thickness is not more than 1 / day. If the film thickness is lower than the above range, it is difficult to produce the film, and if the film thickness is higher than the above range, the water vapor barrier property is likely to be insufficient.

[0023] For example, after being folded in half at 180 degrees and stretched, the water vapor permeability at a temperature of 40°C and humidity of 90% is 0.1 g / m 2 / day or more, 40g / m 2 / day or less, and 0.5 g / m 2 / day or more, 30g / m 2 It is more preferable that the film thickness is not more than 1 / day. If the film thickness is lower than the above range, it is difficult to produce the film, and if the film thickness is higher than the above range, the water vapor barrier property is likely to be insufficient.

[0024] The barrier paper of the present invention can be subjected to secondary processing in order to impart surface functions such as chemical functions, electrical functions, magnetic functions, mechanical functions, friction / wear / lubrication functions, optical functions, thermal functions, biocompatibility, etc. Examples of secondary processing include embossing, painting, adhesion, printing, metallizing (plating, etc.), mechanical processing, surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, coating, etc.), etc. The laminate of the present invention can also be subjected to lamination (dry lamination and extrusion lamination), bag making, and other post-processing.

[0025] When laminating the layers constituting the barrier paper of the present invention, if necessary, the surface of each layer can be subjected to a pretreatment such as corona treatment, ozone treatment, etc. In addition, anchor coating agents such as isocyanate-based (urethane-based), polyethyleneimine-based, polybutadiene-based, and organotitanium-based anchor coating agents, or laminating adhesives such as polyurethane-based, polyacrylic-based, polyester-based, epoxy-based, polyvinyl acetate-based, cellulose-based, and others can be used as desired.

[0026] [Paper base layer] The paper base layer is a layer made of a paper base material, and may be a single layer structure or a multi-layer structure of two or more layers. In the case of a multi-layer structure, each layer may be made of the same or different paper base material, may have the same or different thickness, and may be bonded to each other with an adhesive.

[0027] (Paper base material) There are no particular limitations on the paper base material used in the paper base layer, and any commonly known and commonly used paper base material can be used as long as it has sufficient strength, toughness, heat resistance, and other mechanical, physical, and chemical properties to withstand typical lamination processes and adhesive layer formation processes. The paper base material can be a bleached or unbleached paper base material with strong sizing properties. Specifically, pure white roll paper, kraft paper, paperboard, coated paper, cast coated paper, milk base paper, processed base paper, fine paper, lightly coated printing paper, coated printing paper, resin coated paper, release base paper, double-sided coated release base paper, coated greaseproof paper, impregnated paper, etc. can be used. Among these, coated paper, bleached kraft paper, etc. are particularly preferred. The paper substrate layer may be composed of one layer, or may be composed of two or more layers of the same or different paper substrates. The paper substrates may be laminated by any lamination means via an adhesive layer.

[0028] Coniferous pulp (N wood) or hardwood pulp (L wood) can be used as the raw material pulp for the paper base material, and these can also be used in combination. By changing the content of each, it is possible to adjust the balance of strength, flexibility, smoothness, and barrier properties that can withstand the release paper manufacturing process and the transfer product manufacturing process, and it is possible to produce a paper base material with performance suited to the application. For example, by increasing the content of softwood pulp (N wood), the bending resistance is increased and cracks are prevented. By increasing the content of hardwood pulp (L-wood), the smoothness and / or gas barrier properties can be improved. In order to ensure that the paper base material has sufficient heat resistance, it is preferably neutral paper, and more preferably neutral paper sized using an alkyl ketene dimer as a sizing agent.

[0029] When the paper substrate layer and / or the paper substrate has a multi-layer structure, the paper substrate and / or base paper to be laminated are preferably laminated via an adhesive layer by extrusion lamination or wet lamination. The adhesive for forming the adhesive layer may be the same as that used for the adhesive layer when producing barrier paper or a gas barrier paper-based laminate, but it is preferable to use a lamination adhesive or a wet lamination adhesive.

[0030] In addition, if necessary, plastic compounding agents and additives such as lubricants, crosslinking agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, and pigments can be added to the paper base material for the purpose of improving or modifying processability, heat resistance, weather resistance, mechanical properties, dimensional stability, oxidation resistance, slipperiness, release properties, flame retardancy, mold resistance, electrical properties, strength, etc., and the amount of these added can be determined arbitrarily depending on the purpose, as long as it does not adversely affect other performance properties.

[0031] In order to improve the adhesion between the paper base material and / or base material layer and other layers, if necessary, a paper base material having a coating layer containing a resin or the like on its surface may be used, or the surface of the paper base material and / or paper base material layer that comes into contact with the adhesive may be subjected in advance to a physical surface treatment such as corona discharge treatment, ozone treatment, plasma treatment, glow discharge treatment, sandblasting treatment, etc., or a chemical surface treatment such as oxidation treatment using chemicals.

[0032] [Fixed filler layer] The fixing filling layer is a layer made of a fixing filling resin composition. The fixing filling layer contains at least a fixing filling resin, and may further contain an inorganic filler, an additive, and the like, as necessary. Since the surface of the paper base material is porous and uneven, it is sealed with a fixed sealing layer. The fixed filling layer may be a single layer structure or a multi-layer structure of two or more layers. In the case of a multi-layer structure, each layer may have the same or different composition, the same or different thickness or basis weight, and each layer may be bonded to each other with an adhesive.

[0033] The fixed filling layer can be formed by melt (co)extrusion laminating or coating the fixed filling resin composition on the substrate layer. In the case of forming the layer by application, the fixed filling resin composition, which is a liquid, is applied to the base material layer using a two-roll size press, a gate roll size press, a rod metering size press, an air knife coater, a curtain coater, a direct gravure coater, a reverse gravure coater, an offset gravure coater, a gravure kiss coater, a die coater, a blade coater, a knife coater, an impregnation coater, or the like, and then dried by heating using a dryer.

[0034] (Fixing and sealing resin composition) The filling resin composition is a resin composition for forming a filling layer, contains components for constituting the filling layer, contains at least a filling resin, and may further contain inorganic fillers, additives, etc., as necessary. The fixed filling resin composition may be one that melts at high temperatures, and may further contain an aqueous solvent and be an aqueous solution in which an aqueous resin is dissolved in an aqueous solvent, or an aqueous emulsion in which an aqueous resin is dispersed. In this case, the absence of solvent or the use of water-based solvents reduces the drying time. This suppresses the generation of organic solvent vapor, which is environmentally friendly. In order to suppress the penetration of the solvent into the paper substrate, it is preferable that the solid content in the fixing filling resin composition is high.

[0035] (Fixed sealing resin) The fixed filling resin is preferably one that can fill (fill) minute holes in the surface of the paper base material and further exhibits strong adhesion to the gas barrier layer. When the fixed filling resin composition contains an aqueous solvent, the fixed filling resin is preferably a resin that can be emulsified and dispersed in the aqueous solvent, or a resin that dissolves in the aqueous solvent.

[0036] The fixed filling resin preferably has high water resistance and low solubility in the solvent contained in the gas barrier resin composition so that the fixed filling layer can be easily formed and maintained. Specific examples of the fixing and filling resin include thermoplastic resins, such as polystyrene-based resins, polyurethane-based resins, and acrylic-based resins. One of these resins may be used, or two or more of them may be mixed and used.

[0037] The polystyrene resin refers to a homopolymer of a styrene monomer or a copolymer of a styrene monomer and another copolymerizable monomer. Specific examples of styrene-based monomers include styrene and styrene-based compounds having a substituent such as methylstyrene, paravinylphenol, t-butoxystyrene, and chlorostyrene. Specific examples of the copolymerizable monomer include monomers copolymerizable with styrene-based monomers, such as (meth)acrylic acid, (meth)acrylic acid esters, and acrylonitrile.

[0038] The polystyrene resin preferably has good water resistance. Specific examples of polystyrene-based resins include polystyrene, (methyl)styrene-(meth)acrylic acid copolymers, (methyl)styrene-(meth)acrylic acid ester copolymers, (methyl)styrene-acrylonitrile copolymers, styrene-acrylonitrile-butadiene copolymers, etc. Among these, styrene-acrylic acid copolymers are preferred.

[0039] A polyurethane resin is a (co)polymer having a urethane bond (-NHCOO-) in the main skeleton, and can have various functional groups as required. The polyurethane resin preferably has good water resistance.

[0040] The acrylic resin is a (co)polymer using (meth)acrylic acid or a (meth)acrylic acid ester, and may have various functional groups as required. The acrylic resin preferably has good water resistance.

[0041] (Inorganic filler contained in the fixed sealing layer) The inorganic filler contained in the fixed filling layer can enhance the filling effect of the fixed filling layer on the paper base material. The type of inorganic filler contained in the fixing and sealing layer is not particularly limited, and examples thereof include alumina (aluminum oxide), titanium oxide, zirconia (zirconium oxide), ceria, lithium silicate, diamond, silicon nitride, silicon carbide, iron oxide, mica, kaolin, chromium oxide, silica (silicon oxide), antimony oxide, calcium carbonate, etc. These inorganic fillers may be used alone or in combination of two or more. Among these, it is preferable to use silica, mica, alumina, and kaolin.

[0042] The average particle size of the inorganic filler particles contained in the fixed filling layer is not particularly limited, but in order to stably obtain an excellent filling effect, it is preferable that the average particle size be 0.1 μm or less, although it depends on the thickness and coarseness of the paper base material. The thickness is preferably at most 10 μm, and more preferably at least 0.5 μm and at most 5 μm. If the thickness is smaller or larger than the above range, the sealing effect is likely to decrease.

[0043] The shape of the inorganic filler contained in the fixed filling layer is not particularly limited, and a wide variety of shapes such as a perfect sphere, an oval sphere, a crushed shape, a scale shape, etc. can be used. One type of inorganic filler having these shapes may be used, or two or more types may be mixed and used. Among these, a crushed one is preferred.

[0044] The surface of the inorganic filler contained in the fixed filling layer may be organically modified. The organic modification improves the affinity with the fixed filling resin or the solvent, reduces aggregation, and facilitates uniform dispersion in the fixed filling resin composition or the fixed filling layer.

[0045] The content of the inorganic filler in the fixed filling layer is preferably 1 part by mass or more and 50 parts by mass or less, and more preferably 10 parts by mass or more and 40 parts by mass or less, relative to 100 parts by mass of the fixed filling resin. Within the above range, the fixed filling resin composition exhibits an appropriate melt viscosity for easy melt extrusion or an appropriate viscosity for easy application, and the fixed filling layer can exhibit a sufficient and stable filling effect.

[0046] (Solvent for liquid fixed sealing resin composition) The main component of the solvent of the liquid filling resin composition is water, and the composition may further contain a water-soluble lower alcohol in order to adjust the solubility and dispersibility of the resin component. In order to suppress the penetration of the solvent into the paper substrate, it is preferable that the aqueous solvent has low permeability into the paper substrate.

[0047] [Gas barrier layer] The gas barrier layer is a layer made of a gas barrier resin composition. The gas barrier layer contains at least a gas barrier resin, and may further contain an inorganic filler, an additive, and the like, as necessary. The gas barrier layer may be a single layer structure or a multi-layer structure of two or more layers. In the case of a multi-layer structure, each layer may have the same or different composition, the same or different thickness or coating amount, and each layer may be bonded to each other with an adhesive. The gas barrier layer contains at least a gas barrier resin. Of the gas barrier layers on both sides, at least one of the gas barrier layers on at least one side preferably further contains an inorganic filler.

[0048] The gas barrier layer can be formed by melt (co)extrusion laminating or coating the gas barrier resin composition on the fixed filling layer. When forming the gas barrier resin composition by coating, the gas barrier resin composition, which is a liquid, is coated onto the fixed filling layer using a two-roll size press, a gate roll size press, a rod metering size press, an air knife coater, a curtain coater, a direct gravure coater, a reverse gravure coater, an offset gravure coater, a gravure kiss coater, a die coater, a blade coater, a knife coater, an impregnation coater or the like, and then dried by heating using a dryer.

[0049] (Gas barrier resin composition) The gas barrier resin composition is a resin composition for forming a gas barrier layer, and contains components for constituting the gas barrier layer, including at least a gas barrier resin, and may further contain additives, etc., as necessary. The gas barrier resin composition may be one that melts at high temperatures, and may further contain an aqueous solvent, and may be in the form of an aqueous solution in which an aqueous resin is dissolved in an aqueous solvent, or an aqueous emulsion in which an aqueous resin is dispersed. It can also be . In this case, by using no solvent or an aqueous solvent, the generation of organic solvent vapor during the drying step is suppressed, which is environmentally friendly.

[0050] (Gas barrier resin) The gas barrier resin is a resin having oxygen barrier properties and / or water vapor barrier properties, and is preferably a thermoplastic resin, and is preferably one that exhibits strong adhesion to the fixing and filling resin. When the gas barrier resin composition contains an aqueous solvent, it is further preferably a resin that can be dissolved in the aqueous solvent to be turned into a solution, or a resin that can be emulsified and dispersed in the aqueous solvent. As the barrier resin, one type of resin having both oxygen barrier properties and water vapor barrier properties may be used, or a resin having oxygen barrier properties and a resin having water vapor barrier properties may be used in combination. The oxygen permeability of a 20 μm-thick resin film made of only the barrier resin is 1.0×10 at a temperature of 23°C and humidity of 0%, measured according to a method in accordance with JIS K7126. -4 cc / m 2 / day / atm or more, 20cc / m 2 It is difficult to procure one having a lower oxygen barrier property than the above range, and one having a higher oxygen barrier property than the above range is likely to have insufficient oxygen barrier properties. The barrier resin is a resin film made of only the resin and having a water vapor permeability of 0.1 g / m at a temperature of 40°C and a humidity of 90%, measured according to a method conforming to JIS K7129. 2 / day or more, 30g / m 2 It is difficult to obtain a material having a lower viscosity than the above range, and a material having a higher viscosity than the above range is likely to have insufficient water vapor barrier properties. Furthermore, a resin with a high cohesive energy density is suitable as a barrier resin. For example, polyethylene is not suitable as a barrier resin because of its low cohesive energy density.

[0051] In barrier paper having a layer structure in which at least a fixed filling layer and a gas barrier layer are laminated adjacent to each other in this order on both sides of a paper base layer, specific barrier resins include polyvinyl alcohol-based resins, polyurethane-based resins, ethylene-vinyl alcohol copolymers, polyvinylidene chloride, cycloolefin polymers, etc., and one of these resins may be used, or two or more may be mixed and used. Among these resins, it is particularly preferable to contain a polyvinyl alcohol-based resin or a polyurethane-based resin. The polyvinyl alcohol-based resin is a resin that can be dissolved in an aqueous solvent to form a solution, and the polyurethane-based resin is a resin that can be dispersed in an aqueous solvent to form an emulsion. However, although polyvinyl alcohol-based resins have high oxygen barrier properties and water vapor barrier properties in a low-humidity atmosphere, as the humidity increases, the oxygen barrier properties and water vapor barrier properties, in particular the water vapor barrier property, tend to decrease easily, and the water vapor barrier property is particularly likely to decrease in an atmosphere with a humidity of 70% or more. For this reason, it is preferable that at least one of the gas barrier layers on both sides contains an inorganic filler, and it is more preferable that the gas barrier layers on both sides contain an inorganic filler. When the barrier paper has a layer structure in which a fixed filling layer and a gas barrier layer are laminated adjacent to each other in this order on at least both sides of a paper base layer, the gas barrier layer can exhibit sufficient gas barrier properties even if it contains only a polyvinyl alcohol-based resin as the barrier resin, but it is preferable to use another barrier resin or an inorganic filler in the gas barrier layer on at least one side.

[0052] A polyvinyl alcohol resin is a (co)polymer having a repeating unit of -CH2CH(OH)- in the main skeleton, and can have various functional groups as necessary. In particular, polyvinyl alcohol resins having a high degree of saponification and many hydroxyl groups in one molecule are preferred because they have a high cohesive energy density.

[0053] The polyurethane resin is a (co)polymer having a repeating unit of --NHCOO-- in the main skeleton, and can have various functional groups as required. In particular, polyurethane resins having many hydroxyl groups are preferable because they have a high cohesive energy density.

[0054] (Inorganic filler contained in gas barrier layer) The inorganic filler contained in the gas barrier layer can enhance the gas barrier properties of the gas barrier layer. The type of inorganic filler contained in the gas barrier layer is not particularly limited, and examples thereof include alumina (aluminum oxide), titanium oxide, zirconia (zirconium oxide), ceria, lithium silicate, diamond, silicon nitride, silicon carbide, iron oxide, calcium carbonate, kaolin, chromium oxide, mica, silica (silicon oxide), and antimony oxide. These inorganic fillers may be used alone or in combination of two or more. Among these, mica, silica, alumina, and the like are preferred, and mica is particularly preferred.

[0055] The average particle size of the inorganic filler particles contained in the gas barrier layer is not particularly limited, but in order to stably obtain a balance between excellent gas barrier properties, appropriate rigidity, and flexibility, the average particle size is preferably 0.1 μm or more and 20 μm or less, and more preferably 1 μm or more and 15 μm or less, depending on the roughness of the paper base material. If the average particle size is smaller or larger than the above range, the balance is likely to decrease.

[0056] The shape of the inorganic filler contained in the gas barrier layer is not particularly limited, and a wide variety of shapes such as spherical, elliptical, crushed, and scaly shapes can be used. One type of inorganic filler having these shapes may be used, or two or more types may be mixed and used. Among these, scaly ones are preferred.

[0057] The surface of the inorganic filler contained in the gas barrier layer may be organically modified. Organic modification improves affinity with the gas barrier resin and the solvent, reduces aggregation, and facilitates uniform dispersion in the gas barrier resin composition or the gas barrier layer.

[0058] The content of the inorganic filler in the gas barrier layer is preferably 5 parts by mass or more and 70 parts by mass or less, and more preferably 10 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the barrier resin. Within the above range, the gas barrier resin composition exhibits an appropriate viscosity for easy application, and the gas barrier layer can exhibit sufficient and stable oxygen barrier effect and water vapor barrier effect.

[0059] (Solvent for liquid gas barrier resin composition) The main component of the solvent for the liquid gas barrier resin composition is water, and the solvent may further contain a water-soluble lower alcohol in order to adjust the solubility and dispersibility of the resin component.

[0060] ≪Adhesive layer≫ The adhesive layer can be formed using a general-purpose adhesive that is known and in public use, and the adhesive layer may be formed after the anchor coat layer is formed in advance. The anchor coating agent is not particularly limited, and any of the following anchor coating agents can be used: isocyanate-based (urethane-based), polyethyleneimine-based, polybutadiene-based, organotitanium-based, etc. anchor coating agents; or polyurethane-based, polyacrylic-based, polyester-based, epoxy-based, polyvinyl acetate-based, cellulose-based, and other laminating adhesives.

[0061] The adhesive layer may be, for example, a layer formed by a non-solvent lamination method (non-solvent lamination layer), a layer formed by coating (coating layer), a layer formed by extrusion resin (extrusion resin layer), a layer formed using a wet lamination adhesive (wet lamination layer), or a layer formed by dry lamination using a dry lamination adhesive (dry lamination layer).

[0062] The adhesive may be of any type, such as an organic solvent type, a water-based type, or a solventless type. However, it is preferable that the amount of residual organic solvent in the adhesive layer is small, and preferably is less than 6 mg / m.2 The amount of residual organic solvent is preferably 0 mg / m or less. 2 It is most preferable that the concentration is 6 mg / m 2 It is preferable that: Setting the amount of residual organic solvent in the adhesive layer within the above range is advantageous in that it prevents a decrease in adhesive strength due to the residual organic solvent, prevents distortion at the adhesive interface due to volume shrinkage during drying and the occurrence of minute peeling defects, and prevents deterioration of the gas barrier properties. It is also advantageous in that it prevents the emission of an organic solvent odor from the barrier paper of the present invention. In order to reduce the amount of the residual organic solvent, it is advantageous and preferable to form the adhesive layer using a solventless or water-based adhesive.

[0063] However, if there is sufficient interlayer adhesion, the amount of residual organic solvent in the formed adhesive layer is less than 6 mg / m 2 Even if the amount is more than this, the composition will be sufficiently tolerable in use, and depending on the conditions of use, the organic solvent odor can be resolved by other means, so the above amount does not necessarily have to be met. Here, when the barrier paper of the present invention does not contain a component containing an organic solvent other than in the adhesive layer, the organic solvent content in the adhesive layer can be detected by measuring the organic solvent content of the entire barrier paper. In the present invention, "solvent-free" means that no solvent is actively contained, and the adhesive contains a trace amount of organic solvent remaining in the raw materials, and the amount of residual organic solvent in the formed adhesive layer is 6 mg / m 2 It may be contained within the range as follows.

[0064] Examples of the resin contained in the adhesive include two-liquid curing urethane adhesives, polyester polyurethane adhesives, polyether polyurethane adhesives, acrylic adhesives, polyester adhesives, polyamide adhesives, polyvinyl acetate adhesives, epoxy adhesives, rubber adhesives, polyolefin resins, and acid-modified polyolefin resins obtained by acid-modifying polyolefin resins by graft polymerization or copolymerization with unsaturated carboxylic acids or their anhydrides such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, etc., polyvinyl acetate resins, poly(meth)acrylic resins, polyvinyl chloride resins, and other resins. These resins can be used alone or in combination.

[0065] The adhesive layer may contain additives such as antioxidants, ultraviolet absorbers, light stabilizers, antistatic agents, antiblocking agents, flame retardants, crosslinking agents, and colorants, provided the additives do not impair the properties of the present invention. The thickness of the adhesive layer is not particularly limited, but is preferably 1 g / m 2 More than 20g / m 2 Less than 2 g / m is preferred. 2 More than 10g / m 2 A thickness of 1 μm or less is more preferable, or a thickness of 1 μm or more and 20 μm or less is more preferable, and a thickness of 2 μm or more and 10 μm or less is even more preferable. If the thickness is thinner than the above numerical range, it is difficult to exhibit sufficiently high and stable adhesiveness, and even if the thickness is thicker than the above numerical range, the adhesiveness does not change much and the formation method is easily limited, which is not preferable.

[0066] The organic solvent contained in the organic solvent-based adhesive dissolves the resin raw material that constitutes the organic solvent-based adhesive, has a boiling point and volatility appropriate for the manufacturing process of the barrier paper of the present invention, and has an organic solvent content of 6 mg / m2 or more in the formed adhesive layer. 2 It is preferable to be able to: When a highly polar solvent is used, workability is likely to be poor. For example, when a highly soluble solvent such as acetone is used, the boiling point is low and water from the outside air is likely to be taken in, so that a problem may occur in that the viscosity of the crack-resistant adhesive is likely to increase due to a reaction between water and isocyanate. The main component of the aqueous solvent contained in the aqueous adhesive is water, and the aqueous solvent may further contain a water-soluble lower alcohol in order to adjust the solubility and dispersibility of the resin component.

[0067] <Gas barrier paper laminate> The gas barrier paper-based laminate of the present invention is produced using the environmentally friendly barrier paper of the present invention, and is an environmentally friendly laminate in which the amount of organic solvents used during production is reduced, and the gas barrier paper-based laminate has excellent oxygen barrier properties and water vapor barrier properties.

[0068] <Gas barrier paper-based materials> The gas barrier paper material of the present invention is produced using the environmentally friendly gas barrier paper laminate of the present invention, and is an environmentally friendly paper material in which the amount of organic solvents used during production is reduced. The gas barrier paper material has excellent oxygen barrier properties and water vapor barrier properties, and can be used as a packaging material. The layer structure of the gas barrier paper-based material may be the same as that of the gas barrier paper-based laminate, or may be a layer structure in which a sealant layer (heat seal layer) or a layer for protecting the gas barrier layer is further laminated as necessary.

[0069] The sealant layer may be laminated on the paper base layer or on the gas barrier layer, and may be provided on either one or both surfaces of the gas barrier paper material. For example, gas barrier paper-based materials having layer structures such as sealant layer / paper base layer / fixed sealing layer / gas barrier layer, paper base layer / fixed sealing layer / gas barrier layer / sealant layer, sealant layer / paper base layer / fixed sealing layer / gas barrier layer / sealant layer, etc. can be used using a gas barrier paper-based laminate having a layer structure of paper base layer / fixed sealing layer / gas barrier layer.

[0070] The thickness of the sealant layer is preferably 5 to 500 μm, more preferably 10 to 250 μm, and even more preferably 15 to 100 μm. In the case of a heat seal layer formed by coating, the thickness is 1 to 30 g / m 2 is preferable, and 5 to 20 g / m 2 If the thickness is thinner than the above range, it is difficult to obtain sufficient heat sealability and heat seal strength, whereas if the thickness is thicker than the above range, the cost increases and the rigidity of the gas barrier paper-based material becomes too high, which tends to deteriorate the workability.

[0071] The oxygen barrier property and water vapor barrier property can be expressed by the oxygen permeability and water vapor permeability measured by methods in accordance with JIS K7126 and K7129, respectively. The gas barrier paper material before bending has an oxygen permeability of 0.01cc / m at a temperature of 23°C and humidity of 0%. 2 / day / atm or more, 20cc / m 2 / day / atm or less is preferable, and 0.05cc / m 2 / day / atm or more, 10cc / m 2 It is more preferable that the oxygen barrier property is not more than 1 / day / atm.

[0072] For example, after folding in half at 180 degrees, the oxygen permeability at a temperature of 23°C and humidity of 0% is 0.1cc / m 2 / day / atm or more, 100cc / m 2 / day / atm or less is preferable, and 0.5cc / m 2 / day / atm or more, 50cc / m 2 It is more preferable that the oxygen barrier property is not more than 1 / day / atm.

[0073] The gas barrier paper material before bending has a water vapor permeability of 0.01 g / m at a temperature of 40°C and a humidity of 90%. 2 / day or more, 30g / m2 / day or less is preferable, and 0 .05g / m 2 / day or more, 20g / m 2 It is more preferable that the film thickness is not more than 1 / day. If the film thickness is lower than the above range, it is difficult to produce the film, and if the film thickness is higher than the above range, the water vapor barrier property is likely to be insufficient.

[0074] For example, after folding in half at 180 degrees and bending, the water vapor permeability at a temperature of 40°C and humidity of 90% is 0.1 g / m 2 / day or more, 40g / m 2 / day or less, and 0.5 g / m 2 / day or more, 30g / m 2 It is more preferable that the film thickness is not more than 1 / day. If the film thickness is lower than the above range, it is difficult to produce the film, and if the film thickness is higher than the above range, the water vapor barrier property is likely to be insufficient.

[0075] Specific examples of gas barrier paper-based materials include gas barrier paper-based packaging materials for packaging food, cosmetics, medicines, etc., gas barrier paper-based container materials for producing containers such as cups and plates, gas barrier paper-based lid materials, etc.

[0076] [Sealant layer] The sealant layer is a layer that imparts heat-sealing properties to the gas barrier paper-based material, and contains a heat-sealable resin that can melt and fuse when heated. In the present invention, when the sealant layer is formed by applying a heat-sealing agent, it is also referred to as a heat-sealing layer. The sealant layer may be a single layer or a multi-layer structure of two or more layers. In the case of a multi-layer structure, the compositions of the layers may be the same or different, and the sealant layer may include a layer consisting of only a heat-sealable resin or a layer not containing a heat-sealable resin. Furthermore, the sealant layer may include a functional layer having various functions and an adhesive layer. However, it is preferable that the layer constituting the outermost layer on one side of the gas barrier paper material contains a heat-sealable resin.

[0077] Examples of heat-sealable resins include polyolefin resins, ionomer resins, polyethylene terephthalate (PET), and polyacrylonitrile (PAN). Examples of polyolefin resins include polyethylene resins, polypropylene resins, methylpentene polymers, ethylene-propylene copolymers, cyclic polyolefin resins, cyclic olefin copolymers, and unsaturated carboxylic acid modified polyolefin resins. Specific examples of polyethylene resins include low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, metallocene polyethylene, and the like. Specific examples of the unsaturated carboxylic acid modified polyolefin resin include ethylene-unsaturated carboxylic acid copolymers, ethylene-unsaturated carboxylic acid ester copolymers, etc. More specifically, ethylene-(meth)acrylic acid copolymers, ethylene-(meth)acrylic acid ester copolymers, ethylene-vinyl acetate copolymers, ethylene-(meth)acrylic acid ester-unsaturated carboxylic acid terpolymer resins, etc. Specific examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, etc. The heat-sealable resin may be one of these resins or a combination of two or more of them.

[0078] The sealant layer can be formed by applying a heat-sealable resin, melt (co)extrusion lamination, bonding a film or sheet made of a heat-sealable resin with heat or adhesive, etc. Alternatively, the heat-sealable layer can be formed by applying an emulsion prepared by dispersing a heat-sealable resin in an aqueous solvent, followed by drying. As the above-mentioned film or sheet, any of unstretched film or sheet, and uniaxially or biaxially stretched film or sheet can be used.

[0079] <Gas barrier paper packaging> The gas barrier paper packaging of the present invention is an environmentally friendly packaging produced using the environmentally friendly gas barrier paper material of the present invention, and also includes gas barrier paper containers, and has excellent oxygen barrier properties and water vapor barrier properties. The gas barrier paper-based packaging material of the present invention has excellent oxygen barrier properties and water vapor barrier properties due to the synergistic effect of the fixed sealing layer and the gas barrier layer, and by having the fixed sealing layer and the gas barrier layer on both sides of the paper base layer, it exhibits better oxygen barrier properties and water vapor barrier properties than if they were present on only one side.

[0043] Examples of the gas barrier paper-based packaging body of the present invention include packaging forms such as lids, paper cups, pillow packaging bags, three-sided sealed bags, four-sided sealed bags, standing pouches, and gusset bags, which can be produced by a heat sealing process that heat-seals the sealant layer of the gas barrier paper-based material.

[0080] Normally, when a package is made from a packaging material, the packaging material is subjected to a bending load, and as a result the oxygen barrier property and water vapor barrier property of the packaging material after the package has been formed are reduced compared to the original packaging material, and the oxygen barrier property and water vapor barrier property of the package are reduced. However, the gas barrier paper-based packaging product of the present invention maintains excellent oxygen barrier property and water vapor barrier property because the gas barrier paper-based material of the present invention has excellent oxygen barrier property and water vapor barrier property even after being subjected to a bending load.

[0081] The oxygen permeability of the gas barrier paper-based material that constitutes the gas barrier paper-based packaging after bagging at a temperature of 23°C and humidity of 0% is 0.01cc / m 2 / day / atm or more, 100cc / m 2 / day / atm or less is preferable, and 0.05cc / m 2 / day / atm or more, 50cc / m 2 It is more preferable that the oxygen barrier property is not more than 1 / day / atm. In addition, depending on the sealing method of the gas barrier paper-based packaging material, it is possible to reduce the bending load and further reduce the oxygen permeability. For example, when a gas barrier paper-based packaging material is produced with four-sided sealing, the oxygen permeability can be reduced to 0.01 cc / m 2 / day / atm or more, 20cc / m 2 It can be set to / day / atm or less.

[0082] The water vapor permeability of the gas barrier paper-based material that constitutes the gas barrier paper-based packaging body after bagging at a temperature of 40°C and a humidity of 90% is 0.01 g / m 2 / day or more, 40g / m 2 / day or less, and 0.05 g / m 2 / day or more, 30g / m 2 It is more preferable that the film thickness is not more than 1 / day. If the film thickness is lower than the above range, it is difficult to produce the film, and if the film thickness is higher than the above range, the water vapor barrier property is likely to be insufficient. In addition, depending on the sealing method of the gas barrier paper-based packaging material, it is possible to reduce the bending load and further reduce the water vapor permeability. For example, when a gas barrier paper-based packaging material is produced by sealing on four sides, the water vapor permeability can be reduced to 0.01 g / m 2 / day or more, 20g / m 2 Can be set to / day or less. EXAMPLES

[0083] Details of the raw materials used in the examples are as follows.

[0084] [Gas barrier resin composition] Gas barrier resin composition 1: a urethane-based hybrid gas barrier resin composition prepared by mixing the following: Urethane emulsion 1 (Mitsui Chemicals WPB-341) 27 parts by weight Synthetic mica 1 (NTS-5 (NV6) manufactured by Topy Industries, Ltd.) 67 parts by weight

[0085] Gas barrier resin composition 2: a polyvinyl alcohol-based gas barrier resin composition prepared by the following procedure. The following raw materials were used, and the polyvinyl alcohol powder 1 was first added to warm water and homogenized, and then isopropyl alcohol was added and homogenized to prepare the mixture. Hot water (95℃) 96 parts by mass Polyvinyl alcohol powder 1 (Kuraray Poval PVA124) 4 parts by weight Isopropyl alcohol 4 parts by weight

[0086] Gas barrier resin composition 3: a filler-containing polyvinyl alcohol-based gas barrier resin composition prepared by the following procedure. The following raw materials were used. First, 1 part of polyvinyl alcohol powder was added to warm water and homogenized, and then 1 part of synthetic mica and isopropyl alcohol were added and homogenized to prepare the mixture. Hot water (95℃) 96 parts by mass Polyvinyl alcohol powder 1 (Kuraray Poval PVA124) 4 parts by weight Synthetic mica 1 (NTS-5 (NV6) manufactured by Topy Industries, Ltd.) 20 parts by weight Isopropyl alcohol 4 parts by weight

[0087] [Fixing and sealing resin composition] Fixed sealing resin composition 1: Acrylic resin water-based emulsion, AC-1, manufactured by Sakata Inx Corporation. Fixed sealing resin composition 2: Polyurethane resin water-based emulsion, F-2235D, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[0088] [Paper base material] Paper base material 1: Ryuo Coat, manufactured by Daio Paper Co., Ltd. With a coating layer on one side. Basis weight 55g / m 2 , thickness 49μm. (First) sealing coating agent is applied to the coated surface before use. -Paper base material 2: Daio Paper Co., Ltd., grease-resistant paper S. Basis weight 40g / m 2 , thickness 54 μm. -Paper base material 3: Bleached kraft paper (S) manufactured by Nippon Paper Industries Co., Ltd. Basis weight 50g / m 2 , thickness 60 μm.

[0089] [Heat sealant] Heat seal agent 1: MP4983R, a heat seal agent manufactured by Michelman. Aqueous dispersion of polyethylene resin.

[0090] Example A: Barrier Paper [Example A-1] The fixing filler resin composition 2 was applied to both sides of the paper substrate 1 using a bar coater, and then dried at 100°C (amount applied after drying: 3.6 g / m 2 ) to form first and second fixed filling layers, and then the gas barrier resin composition 1 was applied to both surfaces using a bar coater and then dried at 100°C (application amount after drying: 2.5 g / m 2 ) to form first and second gas barrier layers, thereby obtaining a barrier paper having the following layer structure. Various evaluations were then carried out. Layer structure: first gas barrier layer / first fixed filling layer / paper base layer / second fixed filling layer / first gas barrier layer=gas barrier resin composition 2 (2.5 g / m 2 ) / Fixed sealing resin composition 1 (3.6 g / m 2 ) / Paper base material 1 (49 mm thick) / Fixed sealing resin composition 1 (3.6 g / m 2 ) / gas barrier resin composition 2 (2.5 g / m 2 )

[0091] [Examples A-2 to A-6] Barrier papers were produced in the same manner as in Example A-1 using the combinations of paper substrates, filling resin compositions, and gas barrier resin compositions shown in Table 1, and were evaluated in the same manner.

[0092] [Comparative Examples A-1~3] Using the combinations of paper substrates, fixed filling resin compositions, and gas barrier resin compositions shown in Table 1, paper laminates were obtained in the same manner as in Example A-1, and were similarly evaluated.

[0093] Example B: Gas barrier paper-based material and gas barrier paper-based packaging body [Example B-1] Heat seal agent 1 was applied to the second gas barrier layer side surface of the barrier paper prepared in Example A-1 using a bar coater, and then dried at 100°C (application amount after drying: 10 g / m 2 ) to form a heat seal layer, thereby producing a gas barrier paper material having the following layer configuration. Two sheets of the obtained gas barrier paper material were then stacked with the heat seal layers facing each other, and the four sides were heat sealed to create a gas barrier paper packaging body in the form of a four-sided sealed bag (internal dimensions 15 cm x 15 cm). The gas barrier properties of the gas barrier paper material before the gas barrier paper packaging body was produced and the gas barrier properties of the gas barrier paper material after the bag that constitutes the gas barrier paper packaging body was made were measured. Layer structure: first gas barrier layer / first fixed filling layer / paper base layer / second fixed filling layer / second gas barrier layer=gas barrier resin composition 1 (2.5 g / m 2 ) / Fixed sealing resin composition 1 (2 g / m 2 ) / Paper base material 1 (49 mm thick) / Fixed sealing resin composition 1 (2 g / m 2 ) / Gas barrier resin composition 1 (2.5 g / m 2 ) / Heat seal layer (10g / m 2 )

[0094] [Examples B-2 to B-6] Using the barrier papers produced in each of Examples A-2 to A-6, gas barrier paper materials and gas barrier paper packages were produced in the same manner as in Example B-1, and were similarly evaluated.

[0095] [Comparative examples B-1~3] Using the barrier papers produced in each of Comparative Examples A-1 to A-3, gas barrier paper-based materials were produced in the same manner as in Example B-1, and were similarly evaluated.

[0096] <Evaluation method> [Oxygen permeability] Using an oxygen permeability measuring device (Hitachi High-Tech MOCON), oxygen permeability was measured at a temperature of 23°C and humidity of 0% in accordance with JIS K7126. The measurement limit of the device is 200cc / m 2 / day / atm. The oxygen permeability of the test piece was measured in the direction from the first gas barrier layer to the second gas barrier layer. The bending treatment was performed by folding the barrier paper in half (mountain fold) at 180 degrees once so that the paper layer was on the outside, and then returning it to its original state.

[0097] [Water vapor permeability] Using a Mocon water vapor transmission rate measuring device (Hitachi High-Tech MOCON), the water vapor transmission rate was measured at a temperature of 40°C and a humidity of 90% in accordance with JIS K7129. The measurement limit of the device is 50 g / m 2 / day. The oxygen permeability of the test piece was measured in the direction from the first gas barrier layer to the second gas barrier layer. The bending treatment was performed by folding the barrier paper in half (mountain fold) at 180 degrees once so that the paper layer was on the outside, and then returning it to its original state.

[0098] [Interlayer adhesion] The presence or absence of peeling between any of the layers of the barrier paper was detected by the following procedure. The gas barrier layers and the fixed filling layers on both sides were similarly evaluated. 1) Cellophane tape (15 mm wide x 50 mm long) was attached to the gas barrier layer of the barrier paper with a load of 1,000 g, leaving 10 mm on one end. 2) The above cellophane tape was gripped at a 10 mm portion of one end that was not pressed, and peeled off at a speed of 100 mm / min using a Tensilon measuring device. The peeling condition of the barrier paper was visually observed and classified as follows. Class A: No delamination has occurred. Class B: Only cohesive peeling occurs within the paper base layer. There is no problem with the adhesion between the gas barrier layer and the fixed filling layer. Class C: Peeling occurs between the fixed filling layer and the paper base layer, or cohesive peeling occurs within the fixed filling layer, and the adhesion or breaking strength of the fixed filling layer is insufficient. Category D: Peeling occurs between the gas barrier layer and the fixed filling layer, or cohesive peeling occurs within the gas barrier layer, and the adhesion or fracture strength of the gas barrier layer is insufficient.

[0099] <Summary of Results> The double-sided barrier paper of the invention in all Examples A showed good oxygen barrier properties, water vapor barrier properties and interlayer adhesion before and after bending. Furthermore, the gas barrier paper materials of all Examples B, which were produced by forming a sealant layer (heat seal layer) on the barrier paper of all Examples A with a double-sided configuration, showed good oxygen barrier properties, water vapor barrier properties and interlayer adhesion before and after bag formation for the gas barrier paper-based packaging body. On the other hand, the laminates of Comparative Examples A-1 to A-3 in which neither the first nor the second gas barrier layer contained an inorganic filler exhibited poor water vapor barrier properties both before and after bending. Furthermore, the paper-based materials of Comparative Examples B-1 to B-3, which were produced by forming a sealant layer (heat seal layer) on the laminate of Comparative Example A, showed poor water vapor barrier properties both before and after bag formation for the packaging body.

[0100] [Table 1]

[0101] [Table 2] [Explanation of symbols]

[0102] 1. Barrier paper, gas barrier paper laminate 2 Gas barrier layer 2a First gas barrier layer 2b Second gas barrier layer 3 Fixed filler layer 3a First fixed filling layer 3b Second fixed filling layer 4 Paper base layer 5 Gas barrier paper-based materials 6 Sealant layer (heat seal layer)

Claims

1. At least the laminate has a layer structure in which a fixed filling layer in contact with the paper base layer and a gas barrier layer in contact with the fixed filling layer are laminated on both sides of the paper base layer, The fixing sealing layer contains a styrene-acrylic acid copolymer, The thickness or coating amount of the fixed filling layer is 0.2 μm or more and 25 μm or less, and the coating amount is 0.5 g / m 2 or more and 30 g / m 2 or less, The thickness or coating amount of the gas barrier layer is 0.1 μm or more and 10 μm or less, and the coating amount is 0.3 g / m 2 or more and 10 g / m 2 or less, The fixed sealing layers on both sides have the same or different compositions, the gas barrier layer contains a polyurethane resin and / or a polyvinyl alcohol resin, The gas barrier layers on both sides have the same or different compositions; 13. A barrier paper, wherein the gas barrier layer on at least one side further contains an inorganic filler.

2. 2. The barrier paper according to claim 1, wherein the fixed sealing layer on at least one side further contains an inorganic filler.

3. 3. The barrier paper according to claim 1, wherein the fixed sealing layer on at least one side further contains a polyurethane resin.

4. 4. The barrier paper according to claim 1, wherein the gas barrier layers on both sides further contain an inorganic filler.

5. The oxygen permeability at 23°C and 0% humidity according to JIS K7126 is 0.01 cc / m 2 / day / atm or more, 20cc / m 2 5. The barrier paper according to claim 1, wherein the thermal expansion coefficient is 0.01 to 0.

05.

6. The water vapor permeability at a temperature of 40°C and a humidity of 90% according to JIS K7129 is 0.01 g / m 2 / day or more, 30g / m 2 / day or less.

6. The barrier paper according to any one of 1 to 5.

7. After bending the sheet by folding it in half at 180 degrees and stretching it, the oxygen permeability at 23°C and 0% humidity according to JIS K7126 is 0.1 cc / m 2 / day / atm or more, 100cc / m 2 7. The barrier paper according to claim 1, wherein the thermal expansion coefficient is 0.01 to 0.

05.

8. After bending by folding it in half at 180 degrees and stretching it, the water vapor permeability at a temperature of 40°C and a humidity of 90% according to JIS K7129 is 0.1 g / m 2 / day or more, 40g / m 2 8. The barrier paper according to claim 1, wherein the surface roughness is less than or equal to 100 nm.

9. A gas barrier paper laminate having oxygen barrier properties and water vapor barrier properties, produced using the barrier paper according to any one of claims 1 to 8.

10. A gas barrier paper-based material having oxygen barrier properties and water vapor barrier properties, produced using the gas barrier paper-based laminate according to claim 9.

11. A gas barrier paper-based packaging body having oxygen barrier properties and water vapor barrier properties, produced using the gas barrier paper-based material according to claim 10.

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