JP6313755B2 - Paper barrier packaging materials - Google Patents

Description

  The present invention relates to a paper barrier material used for packaging materials or containers and cups of various products.

Giving gas barrier properties (particularly oxygen barrier properties) to a paper packaging material is important for protecting various products to be packaged from deterioration due to gas, for example, oxidation due to oxygen.
2. Description of the Related Art Conventionally, a paper packaging material in which a metal foil or film is laminated on a paper base material to provide gas barrier properties has been provided. As a material for forming the barrier layer, a metal foil made of metal such as aluminum, a metal vapor-deposited film, a resin film such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyacrylonitrile, or the like is coated. There are a film and a ceramic vapor deposition film in which an inorganic oxide such as silicon oxide or aluminum oxide is vapor-deposited.

  In addition to the above, as paper packaging materials imparted with gas barrier properties, paper gas barrier materials having a gas barrier layer comprising a water-soluble polymer and an inorganic layered compound are disclosed in Patent Document 1 and Patent Document 2. Patent Document 2 discloses a paper gas barrier material in which a barrier layer made of a specific vinyl alcohol polymer is provided on a coating layer.

Further, imparting water resistance (particularly, water vapor barrier property) to the paper packaging material is also important for protecting various products to be packaged from deterioration due to water vapor.
Paper that has been provided with water vapor barrier properties by extruding, laminating, or pasting a resin film having excellent water vapor barrier properties on a paper base material, or a film coated with a resin having excellent water vapor barrier properties to a paper base material. Packaging materials have been proposed. Patent Document 3 discloses a packaging paper having a moisture-proof layer made of synthetic resin latex, wax and inorganic fine particles.

  Furthermore, as a packaging material in which both a gas barrier property and a water vapor barrier property are imparted to a paper packaging material, a packaging material in which a resin having a gas barrier property and a resin having a water vapor barrier property are laminated on a paper base material has been proposed. .

JP 2009-184138 A JP 2003-094574 A JP 2005-162213 A

The packaging material in which both barrier layers are formed by extruding and laminating a gas barrier resin and a water vapor barrier resin on a paper base material (base paper) is limited in the types of resin that can be extruded and laminated. There was a problem that it was not possible to cope with. Moreover, in order to make gas barrier property and water vapor | steam barrier property compatible, it is difficult to recycle paper and a laminate layer for the packaging material which carried out multilayer lamination on the paper base material. Multilayer laminated packaging materials also have the problem of increased CO ₂ emissions during their production. Further, in the case of a multilayer laminate packaging material, it may be necessary to use a specific adhesive resin between the respective laminate layers, and there is a problem that the manufacture thereof is complicated.

  On the other hand, a packaging material in which a paper base material is coated with a resin having a gas barrier property or a resin having a water vapor barrier property has few restrictions on the type of resin that can be used, and can cope with various required qualities. However, when 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, a packaging material having gas barrier properties of Patent Document 1 or Patent Document 2, a good water vapor barrier is provided. However, there is a problem that gas barrier properties cannot be obtained. Moreover, when providing the gas barrier layer of patent document 1 or patent document 2 on the moisture-proof paper which has a moisture-proof layer of patent document 3, since the surface tension of a moisture-proof layer is low and a gas barrier layer is not formed uniformly by repelling, it is enough. The gas barrier property could not be obtained.

  Therefore, 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 present invention provides the following [1] to [11].
[1] A paper barrier packaging material in which a plurality of coating layers are provided on a paper substrate,
The plurality of coating layers include a water vapor barrier layer containing a binder resin formed on a paper substrate, a gas barrier layer formed on the water vapor barrier layer,
The paper barrier packaging material, wherein the gas barrier layer contains anion-modified cellulose nanofibers.
[2] The paper barrier packaging material according to [1], wherein the anion-modified cellulose nanofiber has an average fiber width of 1-1000 nm and an average fiber length of 50-10000 nm.
[3] The anion-modified cellulose nanofiber is a cellulose nanofiber into which a carboxymethyl group is introduced, and the degree of carboxymethyl substitution per glucose unit of cellulose is 0.01 to 0.50 [1] ] Or the laminate according to [2].
[4] The anion-modified cellulose nanofibers are cellulose nanofibers introduced with carboxyl groups, and the amount of carboxyl groups is 0.5 mmol / g to 2 with respect to the absolute dry mass of the cellulose nanofibers introduced with carboxyl groups. The laminate according to [1] or [2], which is 0.0 mmol / g.
[5] The paper barrier packaging material according to any one of [1] to [4], wherein the binder resin of the water vapor barrier layer is a styrene / butadiene based synthetic resin.
[6] The paper barrier packaging material according to any one of [1] to [5], wherein the water vapor barrier layer contains kaolin having an average particle diameter of 5 μm or more and an aspect ratio of 10 or more.
[7] The paper barrier packaging material according to any one of [1] to [6], wherein the water vapor barrier layer contains a pigment having an average particle diameter of 5 μm or less.
[8] The paper barrier packaging material according to any one of [1] to [7], wherein the water vapor barrier layer contains a crosslinking agent.
[9] The paper barrier packaging material according to any one of [1] to [8], wherein the gas barrier layer contains an inorganic pigment having an average particle diameter of 5 μm or more and an aspect ratio of 10 or more.
[10] The paper barrier packaging material according to any one of [1] to [9], wherein the gas barrier layer contains a crosslinking agent.
[11] The coating amount of the water vapor barrier layer coating weight of the dry weight in 4~30g / ^{m 2,} the gas barrier layer is characterized by dry weight is 0.2 to 10 g / ^{m 2} [1] The paper barrier packaging material according to any one of to [10].

  According to the present invention, it is possible to provide a paper barrier packaging material having a plurality of coating layers on a paper base material, which has both excellent gas barrier properties and water vapor barrier properties. In the paper barrier packaging material of the present invention, the water vapor barrier layer and the gas barrier layer are formed by coating, and since various resins can be used, it is possible to cope with various required qualities. Specifically, not only food, wet tissue, cosmetics, pharmaceuticals, agricultural chemicals, etc., but also packaging of electronic materials such as semiconductors, electronic paper, organic electroluminescence device elements, solar cell elements, etc., which may be deteriorated by moisture or oxidation. It can be suitably used as a material. The paper barrier packaging material of the present invention can be recycled as it is, and is easier to recycle than a laminated paper that requires the laminate layer and the paper substrate to be separated and recycled. Moreover, since the paper barrier packaging material of the present invention is formed by coating and does not require an adhesive resin layer, the manufacturing process can be simplified.

  In the present invention, a paper barrier packaging material (hereinafter also 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 also referred to as “base paper”). It is. The two types of barrier layers are formed by applying an aqueous coating material.

  The reason why the paper barrier packaging material of the present invention in which the water vapor barrier layer is further formed on the paper substrate and the gas barrier layer is formed thereon has both excellent water vapor barrier properties and gas barrier properties is presumed as follows.

  In many cases, the gas barrier layer is formed using a highly hydrophilic material (hereinafter sometimes referred to as “hydrophilic material”). When a gas barrier layer and a water vapor barrier layer are provided in this order on a paper base material, moisture in the air that permeates through the paper base material acts to deteriorate the gas barrier layer containing the hydrophilic material. On the other hand, when a water vapor barrier layer containing a resin with good water resistance and a gas barrier layer are provided in this order on the paper base material, moisture through the paper base material is blocked by the water vapor barrier layer. The influence (deterioration) of can be prevented. For this reason, the paper barrier packaging material of the present invention has good water vapor barrier properties and gas barrier properties.

  In the paper barrier material of the present invention, the gas barrier layer side is usually used as the contents (packaged material) side and the paper base material side is used as the outside air side (outer surface). Since the moisture of the outside air can be prevented from penetrating into the inside, the structure of the present invention is effective if the package is a dry substance. When packaging a wet product, an extruded laminate layer of a resin or a laminate layer of a film may be additionally formed on the gas barrier layer on the content side.

1. Paper base material In this invention, a paper base material is a sheet | seat which consists of a pulp, a filler, and various adjuvants. Pulp was obtained from hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), chemical pulp such as sulfite pulp, mechanical pulp such as stone grind pulp, thermomechanical pulp, kenaf, bamboo, hemp, etc. There are non-wood fibers. These materials can be appropriately mixed and used. Among these, chemical pulps such as hardwood bleached kraft pulp (LBKP) and softwood bleached kraft pulp (NBKP) are preferable. Chemical pulp is less prone to foreign matter contamination in the base paper, is less likely to discolor over time when recycled after being used in used paper containers, and has high whiteness, It is suitable for reasons such as good feeling and high use value as a packaging material.

  As the filler, known fillers such as white carbon, talc, kaolin, clay, heavy calcium carbonate, light calcium carbonate, titanium oxide, zeolite, and synthetic resin filler can be used. In addition, sulfuric acid bands and various anionic, cationic, nonionic or amphoteric yield improvers, drainage improvers, paper strength enhancers and internal additive sizing agents, etc. Can be used. Furthermore, dyes, fluorescent brighteners, pH adjusters, antifoaming agents, pitch control agents, slime control agents and the like can be added as necessary.

The paper base production (papermaking) method is not particularly limited, and the papermaking is carried out using an acid papermaking machine, neutral papermaking machine, or alkaline papermaking machine using a known long web former, on-top hybrid former, or gap former machine. Thus, a paper base material can be manufactured. Moreover, as a paper base material, the paper base material whose basic weight used for general coated paper is about 25-400 g / m < ² > is preferable.
Furthermore, it is possible to treat the surface of the paper substrate with various chemicals. Examples of the agent used include oxidized starch, hydroxyethyl etherified starch, oxygen-modified starch, polyacrylamide, polyvinyl alcohol, surface sizing agent, water-resistant agent, water retention agent, thickener, lubricant and the like. These can be used alone or in admixture of two or more.
The surface treatment method for the paper substrate is not particularly limited, but a known coating apparatus such as a rod metalling type size press, a pound type size press, a gate roll coater, a spray coater, a blade coater, or a curtain coater is used. be able to.

2. Water vapor barrier layer 1) Binder resin Binder resin to be included in the water vapor barrier layer includes styrene / butadiene, styrene / acrylic, ethylene / vinyl acetate, butadiene / methyl methacrylate, vinyl acetate / butyl acrylate, etc. Examples thereof include a polymer, a polyolefin / maleic anhydride copolymer, and an acrylic acid / methyl methacrylate copolymer. These can be used alone or in admixture of two or more. In particular, a styrene / butadiene copolymer is preferable from the viewpoint of water vapor barrier properties.

  In the present invention, the styrene / butadiene copolymer is obtained by emulsion polymerization by combining styrene and butadiene as main constituent monomers and various comonomers intended for modification. Examples of comonomers include methyl methacrylate, acrylonitrile, acrylamide, hydroxyethyl acrylate, unsaturated carboxylic acids such as itaconic acid, maleic acid, and acrylic acid.

  The binder resin contained in the water vapor barrier layer is preferably an emulsion type resin dispersed in water with an emulsifier from the viewpoint of water vapor barrier properties. Examples of the emulsifier include, but are not limited to, anionic surfactants such as sodium oleate, rosin acid soap, sodium alkylallylsulfonate, sodium dialkylsulfosuccinate, and the like. These may be used alone or nonionic. It can be used in combination with a surfactant. Furthermore, you may use an amphoteric or cationic surfactant as needed.

  In the present invention, it is preferable that the coating material forming the water vapor barrier layer does not contain a water-repellent component such as hydrocarbon, silicone resin, fluorine resin, fatty acid and ester of fatty acid and alcohol. Note that conventional packaging materials having water vapor barrier properties are generally provided with a resin containing a water repellent component. When the water repellent component is contained, the affinity between the water vapor barrier layer and the gas barrier layer is lowered, and moisture and gas permeated from one layer promote interface peeling, which is not preferable.

2) Additive Pigment In the present invention, the water vapor barrier property can be improved by incorporating a pigment into the water vapor barrier layer. Moreover, the adhesiveness of a water vapor | steam barrier layer and a gas barrier layer improves by containing a pigment.

Examples of the pigment include inorganic pigments and organic pigments.
Inorganic pigments are kaolin, clay, engineered kaolin, delaminated clay, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicate, colloidal silica, satin white Etc.
Examples of the organic pigment include a solid type, a hollow type, and a core-shell type.
These pigments can be used alone or in admixture of two or more. The pigment is suitable for a large and flat shape. Furthermore, water vapor barrier property improves by using a large particle size and a small particle size together.

Among these pigments, inorganic pigments such as kaolin having a flat shape improve the barrier property of water vapor. In particular, kaolin having an average particle diameter of 5 μm or more and an aspect ratio of 10 or more is more preferable. When the flat pigment is distributed in parallel to the coating layer, the water vapor that has penetrated into the water vapor barrier layer is blocked by the flat pigment from moving in the thickness direction, and moves in a detour. The moving distance becomes longer and the barrier property is improved. If the aspect ratio of the pigment to be added is small, the number of times the water vapor bypasses in the coating layer is reduced, and the distance traveled is not so long. As a result, the water vapor barrier property is inferior to that of a flat and large particle size pigment. It becomes.
The flat pigment can be expected to have the same effect even in the gas barrier layer.

  In addition to kaolin, mica and montmorillonite can be used as the flat pigment. However, the dispersion of mica and montmorillonite has a lower solid concentration than the dispersion of kaolin, and the coating solution for the water vapor barrier layer using mica and montmorillonite has a low concentration. In the water vapor barrier layer formed from a low-concentration coating solution, kaolin that can increase the concentration of the coating solution is more suitable because the pigment is less likely to be oriented parallel to the coating layer.

  In addition to the flat pigment described above, a water vapor barrier property can be further improved by further adding a pigment having an average particle diameter of 5 μm or less to the water vapor barrier layer.

  In the present invention, a pigment having an average particle diameter of 5 μm or less is further added to the water vapor barrier layer containing kaolin having an average particle diameter of 5 μm or more and an aspect ratio of 10 or more from the viewpoint of improvement of the water vapor barrier property and adhesion to the gas barrier layer. It is preferable to contain. Water vapor that has a structure in which a pigment having an average particle diameter of 5 μm or less enters between kaolins having an average particle diameter of 5 μm or more and an aspect ratio of 10 or more that exist in a multi-layered manner, is forced to move along the flat kaolin surface, The movement is blocked by the small pigment particles. In other words, when a flat pigment and a pigment with a small average particle size are contained in the water vapor barrier layer, a small particle size pigment is filled in the void formed by the flat and large particle size pigment in the water vapor barrier layer. In this state, since the water vapor moves around the pigment, the high water vapor barrier property is exhibited as compared with the water vapor barrier layer in which the pigment having a small particle diameter is not mixed.

  In the present invention, the mixing ratio of the kaolin having an average particle diameter of 5 μm or more and an aspect ratio of 10 or more and the pigment having an average particle diameter of 5 μm or less, more preferably 3 μm or less is preferably 50/50 to 99/1 by dry weight. . If the ratio of kaolin having an average particle diameter of 5 μm or more and an aspect ratio of 10 or more is less than the above range, the distance that the water vapor bypasses the coating layer does not become so long that sufficient water vapor barrier properties cannot be obtained. On the other hand, when the amount is larger than the above range, the void formed by the large particle size pigment in the coating layer cannot be sufficiently filled with the pigment having an average particle size of 5 μm or less, so that the water vapor barrier property is not improved.

  In the present invention, the pigments having an average particle size of 5 μm or less include kaolin, clay, engineered kaolin, delaminated clay, heavy 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, and core-shell type can be used alone or in combination of two or more. Of these pigments, heavy calcium carbonate is preferred.

  When the water vapor barrier layer contains a pigment, the binder resin and the pigment are used in an amount of 5 to 200 parts by weight of the binder resin (dry weight) with respect to 100 parts by weight of the pigment (dry weight). Preferably, it is 35-150 weight part of binder resin more preferably. In addition to the binder resin and pigment, various commonly used auxiliaries such as dispersants, thickeners, water retention agents, antifoaming agents, water resistance agents, dyes and fluorescent dyes should be used for the water vapor barrier layer. Can do.

3) Crosslinking agent In this invention, it is preferable to add the crosslinking agent represented by the polyvalent metal salt etc. to the water vapor | steam barrier layer. Since the crosslinking agent causes a crosslinking reaction with the binder resin contained in the water vapor barrier layer, the number of bonds (crosslinking points) in the water vapor barrier layer increases. That is, the water vapor barrier layer has a dense structure and exhibits good water vapor barrier properties.

In the present invention, the type of the crosslinking agent is not particularly limited, and in accordance with the type of the binder resin contained in the water vapor barrier layer, a polyvalent metal salt (copper, zinc, silver, iron, potassium, sodium, Compound in which polyvalent metals such as zirconium, aluminum, calcium, barium, magnesium and titanium are combined with ionic substances such as carbonate ion, sulfate ion, nitrate ion, phosphate ion, silicate ion, nitrogen oxide and boron oxide) , An amine compound, an amide compound, an aldehyde compound, a hydroxy acid, and the like. The number of blending parts of the crosslinking agent is not particularly limited as long as it is within the range of paint concentration and paint viscosity that can be applied. In the case of using a styrene-based binder resin such as styrene / butadiene or styrene / acrylic that exhibits an excellent effect of water vapor barrier properties, it is preferable to use a polyvalent metal salt from the viewpoint of expression of a crosslinking effect. . Furthermore, potassium alum (AlK (SO ₄ ) ₂ · 12H ₂ O) is more preferable.

  The addition amount of a crosslinking agent is 1-10 weight part with respect to 100 weight part of binder resin used for a water vapor | steam barrier layer. More preferably, it is 3 to 5 parts by weight. When the amount is less than 1 part by weight, a sufficient effect cannot be obtained, and when the amount is more than 10 parts by weight, the viscosity of the coating solution is remarkably increased, which makes coating difficult.

  In the present invention, when a crosslinking agent is added to the coating solution for forming the water vapor barrier layer, it is preferable to add the crosslinking agent to a coating solution after dissolving the crosslinking agent in a polar solvent such as an aqueous ammonia solution. By dissolving the cross-linking agent in a polar solvent, the cross-linking agent forms hydrogen bonds with the polar solvent. Therefore, even if the solution of the crosslinking agent is blended in the coating solution, the crosslinking reaction with the latex does not occur immediately, and the thickening of the paint can be suppressed. In that case, after the polar solvent is volatilized after coating on the paper substrate, it is presumed that a crosslinking reaction between the crosslinking agent and the binder occurs, and a dense water vapor barrier layer is formed.

4) Contact angle of water vapor barrier layer surface In the present invention, the water contact angle 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 °. It is. When 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. When the angle is less than 90 °, repulsion between the water vapor barrier layer and the gas barrier layer can be suppressed, and peeling between the two layers can be suppressed. This contact angle is a standard for estimating the affinity between the water vapor barrier layer and the gas barrier layer.

  The method for adjusting the contact angle with water on the surface of the water vapor barrier layer is not limited, but examples thereof include use of a resin for the water vapor barrier layer having a low contact angle with water, addition of a pigment, and the like. Can do.

As the water vapor barrier property of the water vapor barrier layer of the present invention, the water vapor transmission rate is preferably 500 g / m ² · day or less under the conditions of a temperature of 40 ± 0.5 ° C. and a relative humidity of 90 ± 2%, and 300 g More preferably, it is not more than / m ² · day.
In the embodiment of the present invention, a water vapor transmission rate of 150 to 380 g / m ² · day is achieved, and the package is made of water vapor by using the paper barrier packaging material provided with the water vapor barrier layer of the present invention. Can be protected from deterioration.

3. Gas Barrier Layer In the present invention, it is important to use an anion-modified cellulose nanofiber that is a hydrophilic material as a gas barrier material in the gas barrier layer.

1) Anion-modified cellulose nanofiber In the present invention, the anion-modified cellulose nanofiber can be obtained by fibrillating the following cellulose raw material that has been anion-modified, and has an average fiber length of 50 to 10,000 nm and an average fiber width of 1 to 1000 nm. It is a cellulose fiber.

  The cellulose raw material is wood-derived kraft pulp or sulfite pulp, powdered cellulose obtained by pulverizing them with a high-pressure homogenizer, a mill, or the like, or microcrystalline cellulose powder purified by chemical treatment such as acid hydrolysis. In addition, plant-derived cellulose raw materials such as kenaf, hemp, rice, bacus, and bamboo can also be used. However, if a large amount of hardwood-derived lignin remains in the cellulose raw material, there is a risk of inhibiting the oxidation reaction of the raw material. Therefore, in the present invention, the cellulose raw material obtained by the method for producing chemical pulp is preferred. Moreover, in order to remove lignin, it is more preferable to perform a known bleaching treatment on the cellulose raw material thus obtained.

  In addition, the cellulose raw material described above, which has been refined with a high-speed rotating type, colloid mill type, high-pressure type, roll mill type, ultrasonic type dispersing device, wet high-pressure or ultra-high pressure homogenizer, etc., may be used as the cellulose raw material. it can.

2) Anion-modified cellulose raw material In the present invention, anion-modified cellulose can be obtained by anionic modification such as carboxymethylation or carboxylation of the cellulose raw material. As an example, the following manufacturing method can be mentioned.

2-1) Carboxymethylation A cellulose raw material, a solvent, and a mercerizing agent are mixed, the reaction temperature is 0 to 70 ° C., preferably 10 to 60 ° C., and the reaction time is 15 minutes to 8 hours, preferably 30 minutes to 7 hours. Perform mercerization. As the solvent, 3 to 20 times by weight of a lower alcohol having 1 to 5 carbon atoms, specifically methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butanol, isobutanol, tertiary, as a cellulose raw material. A mixture medium of butanol, pentanol or the like alone or a mixture of two or more kinds and water can be used. As the mercerizing agent, 0.5 to 20 times moles of alkali metal hydroxide, specifically sodium hydroxide or potassium hydroxide can be used per glucose residue of the cellulose raw material.
Thereafter, a carboxymethylating agent is added in an amount of 0.05 to 10.0 times mol per glucose residue, a reaction temperature of 30 to 90 ° C., preferably 40 to 80 ° C., and a reaction time of 30 minutes to 10 hours, preferably 1 hour. Carboxymethylated cellulose is obtained by performing an etherification reaction for -4 hours.

  In this invention, it is preferable that the substitution degree of the carboxymethyl group per glucose unit of carboxyl methylated cellulose is 0.01-0.50, and it is more preferable that it is 0.05-0.30. By introducing a carboxymethyl group into cellulose, the celluloses repel each other electrically. For this reason, the cellulose which introduce | transduced the carboxymethyl group can be nano-defibrated easily. In addition, when the substitution degree of the carboxymethyl group per glucose unit is smaller than 0.01, the nano-defibration cannot be sufficiently performed. On the other hand, if the substitution degree of the carboxymethyl group per glucose unit is larger than 0.50, it becomes easy to swell or dissolve, so that it may not be obtained as a nanofiber.

  In addition, the substitution degree of a carboxymethyl group can be measured with the following method.

(Measurement method of substitution degree of carboxymethyl group per glucose unit)
About 2.0 g of carboxymethylated cellulose fiber (absolutely dry) was placed in a 300 mL Erlenmeyer flask with a stopper. 100 mL of methanol nitric acid (a solution obtained by adding 100 mL of special concentrated nitric acid to 1000 mL of anhydrous methanol) was added, and the mixture was shaken for 3 hours to convert the carboxymethyl cellulose salt (CM cellulose) to hydrogenated CM cellulose. About 2.0 g of hydrogenated CM-modified cellulose (absolutely dried) was precisely weighed and placed in a 300 mL conical flask with a stopper. Hydrogenated CM-modified cellulose was moistened with 15 mL of 80% methanol, 100 mL of 0.1 N NaOH was added, and shaken at room temperature for 3 hours. Excess NaOH was back titrated with 0.1 N H ₂ SO ₄ using phenolphthalein as an indicator.

The degree of substitution (DS) of the carboxymethyl group was calculated by the following formula:
A = [(100 × F ′ − (0.1N H ₂ SO ₄ ) (mL) × F) × 0.1] / (absolute dry mass of hydrogenated CM-modified cellulose (g))
DS = 0.162 × A / (1−0.058 × A)
A: 1N NaOH amount (mL) required for neutralizing 1 g of hydrogenated CM-modified cellulose
F: Factor of 0.1N H ₂ SO ₄ F ′: Factor of 0.1N NaOH

2-2) Carboxylation (oxidation)
Cellulose introduced with a carboxyl group by oxidizing the cellulose raw material in water using an oxidizing agent in the presence of a compound selected from the group consisting of N-oxyl compounds and bromides, iodides or mixtures thereof (Hereinafter also referred to as “oxidized cellulose”).

  An N-oxyl compound refers to a compound capable of generating a nitroxy radical. As the N-oxyl compound, any compound can be used as long as it promotes the target oxidation reaction. For example, the compound shown by the following general formula (Formula 1) is mentioned.

(In Formula 1, R ^{1 to} R ⁴ represent the same or different alkyl groups having 1 to 4 carbon atoms.)
Of the substances represented by Formula 1, 2,2,6,6-tetramethyl-1-piperidine-oxy radical (hereinafter referred to as TEMPO) is preferable. Further, the N-oxyl compound represented by any one of the following formulas 2 to 4, that is, the hydroxyl group of 4-hydroxy TEMPO was etherified with alcohol or esterified with carboxylic acid or sulfonic acid to impart moderate hydrophobicity. A 4-hydroxy TEMPO derivative or 4-acetamido TEMPO having an appropriate hydrophobicity by acetylating the amino group of 4-amino TEMPO is preferable because it is inexpensive and can provide uniform oxidized cellulose.

(In formulas 2 to 4, R represents a linear or branched alkyl group having 1 to 4 carbon atoms.)
Furthermore, an N-oxyl compound represented by the following formula 5, that is, an azaadamantane-type nitroxy radical, is preferable because it can efficiently oxidize a cellulose raw material in a short time and is less likely to break the cellulose chain.

(In Formula 5, R ⁵ and R ⁶ represent hydrogen or the same or different linear or branched alkyl group having 1 to 6 carbon atoms.)
The amount of the N-oxyl compound used is not particularly limited as long as it is a catalytic amount capable of introducing a carboxyl group into cellulose to such an extent that cellulose can be converted into nanofibers. For example, 0.01 to 10 mmol is preferable, 0.01 to 1 mmol is more preferable, and 0.05 to 0.5 mmol is more preferable with respect to 1 g of the absolutely dry cellulose raw material.

  Bromide is a compound containing bromine, examples of which include alkali metal bromides that can dissociate and ionize in water. Further, an iodide is a compound containing iodine, and examples thereof include alkali metal iodide. The amount of bromide or iodide used can be selected as long as the oxidation reaction can be promoted. The total amount of bromide and iodide is, for example, preferably from 0.1 to 100 mmol, more preferably from 0.1 to 10 mmol, and even more preferably from 0.5 to 5 mmol, with respect to 1 g of an absolutely dry cellulose raw material.

  As the oxidizing agent, known ones can be used, and for example, halogen, hypohalous acid, halous acid, perhalogen acid or salts thereof, halogen oxide, peroxide and the like can be used. Of these, sodium hypochlorite is preferable because it is inexpensive and has a low environmental impact. The appropriate amount of the oxidizing agent used is, for example, preferably 0.5 to 500 mmol, more preferably 0.5 to 50 mmol, still more preferably 1 to 25 mmol, and most preferably 3 to 10 mmol with respect to 1 g of the absolutely dry cellulose raw material. preferable.

  The oxidation reaction of cellulose is allowed to proceed even under relatively mild conditions. Therefore, the reaction temperature may be a room temperature of about 15 to 30 ° C. As the reaction proceeds, a carboxyl group is generated in the cellulose, so that the pH of the reaction solution is reduced. In order to advance the oxidation reaction efficiently, an alkaline solution such as an aqueous sodium hydroxide solution is added to maintain the pH of the reaction solution at 9 to 12, preferably 10 to 11. The reaction medium is preferably water because it is easy to handle and hardly causes side reactions.

  The reaction time in the oxidation reaction can be appropriately set according to the degree of progress of oxidation, and is usually 0.5 to 6 hours, for example, about 0.5 to 4 hours.

  The oxidation reaction may be performed in two stages. For example, oxidized cellulose obtained by filtration after the completion of the first stage reaction is oxidized again under the same or different reaction conditions, so that the cellulose is not subject to reaction inhibition by the salt produced as a by-product in the first stage reaction. A carboxyl group can be efficiently introduced into the raw material.

  In addition, the cellulose raw material may be appropriately subjected to alkali treatment before the oxidation step to change the crystal form to the II type. Ordinary cellulose is a type I crystal, but if it contains a type II crystal, the oxidant easily enters and the reaction efficiency is improved.

  The amount of carboxyl groups in oxidized cellulose is preferably 0.5 to 2.0 mmol / g with respect to the absolute dry mass of cellulose. The amount of the carboxyl group can be adjusted by adjusting the oxidation reaction time, adjusting the oxidation reaction temperature, adjusting the pH during the oxidation reaction, the amount of N-oxyl compound, bromide, iodide, or oxidizing agent added.

  The obtained oxidized cellulose is preferably washed.

The amount of carboxyl groups was prepared by preparing 60 ml of a 0.5 mass% slurry (aqueous dispersion) of oxidized cellulose, adding 0.1 M hydrochloric acid aqueous solution to pH 2.5, and then dropping 0.05 N aqueous sodium hydroxide solution dropwise. Then, the electrical conductivity is measured until the pH reaches 11, and can be calculated from the amount of sodium hydroxide (a) consumed in the weak acid neutralization stage where the change in electrical conductivity is gradual, using the following equation. :
Carboxyl group amount [mmol / g oxidized cellulose] = a [ml] × 0.05 / oxidized cellulose mass [g].

<Defibration of anion-modified cellulose>
A dispersion containing the anion-modified cellulose obtained above is prepared, and the anion-modified cellulose is fibrillated in the dispersion to form nanofibers. “Nanofiber” means that cellulose is converted into cellulose nanofibers having an average fiber width of 1-1000 nm, preferably 2-150 nm, more preferably 3-30 nm, and an average fiber length of 50-10000 nm, preferably 100-4500 nm. It means to process. A dispersion is a liquid in which the anion-modified cellulose is dispersed in a dispersion medium. From the viewpoint of ease of handling, the dispersion medium is preferably water.

  In order to disentangle anion-modified cellulose and disperse it in a dispersion medium, a strong shearing force is applied to the dispersion using a high-speed rotating type, colloid mill type, high pressure type, roll mill type, ultrasonic type device, etc. It is preferable. In particular, in order to efficiently obtain anion-modified cellulose nanofibers, it is preferable to use a wet high pressure or ultrahigh pressure homogenizer capable of applying a pressure of 50 MPa or more to the dispersion and applying a strong shearing force. The pressure is more preferably 100 MPa or more, and further preferably 140 MPa or more. By this treatment, the anion-modified cellulose is fibrillated to form anion-modified cellulose nanofibers, and the anion-modified cellulose nanofibers are dispersed in the dispersion medium.

  The anion-modified cellulose concentration in the dispersion used for the treatment is 0.1% (w / v) or more, preferably 1 to 50% (w / v), more preferably 1 to 10% (w / v). Preferably, 2 to 10% (w / v) is more preferable, and 3 to 10% (w / v) is most preferable.

In this invention, it is preferable that content of the anion modified cellulose nanofiber contained in a gas barrier layer shall be 0.1-9 g / m < ² > by dry weight.

3) Binder resin In the present invention, as a binder resin, the saponified polyvinyl alcohol, the partially saponified polyvinyl alcohol, the cation-modified polyvinyl alcohol, the carboxy-modified polyvinyl alcohol, the ethylene copolymerized polyvinyl alcohol, and the polyvinyl as long as the desired effects are not impaired. Water-soluble polymers such as pyrrolidone, starch, methylcellulose, sodium alginate, carboxymethylcellulose can be used in combination. In addition, when using together an anion modified cellulose nanofiber and binder resin, the compounding ratio is anion modified cellulose nanofiber / binder resin = 1-99 / 99-1.

4) Pigment In the present invention, the gas barrier property can be improved by incorporating a pigment into the gas barrier layer. The pigments used in the gas barrier layer include kaolin, clay, engineered kaolin, delaminated clay, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicate, There are inorganic pigments such as colloidal silica, satin white, and mica, and organic pigments such as a solid type, a hollow type, and a core-shell type. These can be used alone or in admixture of two or more. In these, it is preferable to use an inorganic pigment from the point of gas barrier property.

  It is more preferable to use an inorganic pigment (especially kaolin) having an average particle diameter of 5 μm or more and an aspect ratio of 10 or more, and an inorganic pigment (particularly kaolin) having an average particle diameter of 5 μm or more and an aspect ratio of 50 or more. Is particularly preferred. When a pigment is contained in the gas barrier layer, a gas such as oxygen moves around the pigment. For this reason, compared with the gas barrier layer which consists of anion modified cellulose nanofiber which does not contain a pigment, it has the outstanding gas barrier property in a high-humidity atmosphere.

  In the present invention, the blending ratio (dry weight) of the pigment, the anion-modified cellulose nanofiber and the water-soluble polymer contained in the gas barrier layer is the total amount of the pigment / anion-modified cellulose nanofiber and the binder resin = 1/100 to 1000 / 100 is preferable. If the ratio of the pigment is out of the above range, sufficient gas barrier properties are not exhibited.

5) Crosslinking agent In the present invention, it is preferable to add a crosslinking agent typified by a polyvalent metal salt or the like to the gas barrier layer. The cross-linking agent bonds the hydroxyl group or anion-modified group of the anion-modified cellulose nanofiber in a cross-linked structure, so the amount of hydroxyl group that loosens (or breaks) when high humidity is reduced, and the water resistance of the entire layer is improved. To do. Therefore, it is possible to suppress a decrease in gas barrier properties under high humidity.

  In the present invention, the type of the crosslinking agent is not particularly limited, and polyvalent metal salts (copper, zinc, silver, iron, potassium, sodium, zirconium, aluminum, calcium, barium, magnesium, titanium, etc.) A compound in which a metal is combined with an ionic substance such as carbonate ion, sulfate ion, nitrate ion, phosphate ion, silicate ion, nitrogen oxide, boron oxide), amine compound, amide compound, aldehyde compound, hydroxy acid, etc. Can be used. The number of blending parts of the crosslinking agent is not particularly limited as long as it is within the range of paint concentration and paint viscosity that can be applied. In addition, it is preferable to use a polyvalent metal salt, and it is more preferable to use a potassium alum from a viewpoint of expression of the crosslinking effect with respect to anion-modified cellulose nanofiber.

  The addition amount of a crosslinking agent is 1-10 weight part with respect to 100 weight part of anion modified cellulose nanofiber used for a gas barrier layer, More preferably, it is 3-5 weight part. When the amount is less than 1 part by weight, a sufficient effect cannot be obtained, and when the amount is more than 10 parts by weight, the viscosity of the coating solution is remarkably increased, which makes coating difficult.

6) Additive In the present invention, when the pigment is blended into the anion-modified cellulose nanofiber, it is preferable to add and mix the slurry of the pigment dispersed in water.

  In the present invention, in the gas barrier layer, various commonly used auxiliaries such as a dispersant, a thickener, a water retention agent, a defoaming agent, a water resistance agent, a dye, and a fluorescent dye are used in addition to the binder resin and the pigment. be able to.

4). About coating In this invention, it does not specifically limit about the coating method of a water vapor | steam barrier layer and a gas barrier layer, A well-known coating apparatus can be used. Examples include 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, and a gate roll coater. In addition, as a method for drying the coating layer, for example, a normal method such as a steam heater, a gas heater, an infrared heater, an electric heater, a hot air heater, a microwave, a cylinder dryer, or the like is used.

In the present invention, the coating amount of the water vapor barrier layer is preferably to 4~30g / ^{m 2} by dry weight, more preferably from 6 to 25 g / ^{m 2,} more preferably at 10 to 20 g / ^{m 2} Preferably there is. If the coating amount is less than 4 g / m ² , it becomes difficult to completely coat the base paper with the coating liquid, and sufficient water vapor barrier properties cannot be obtained. There is a problem that gas barrier properties cannot be obtained. On the other hand, when it is more than 30 g / m ² , the drying load at the time of coating increases, which is not preferable from the viewpoints of both operation and cost.

In the present invention, the coating amount of the gas barrier layer is preferably 0.2 to 10 g / m ² in terms of dry weight. If the coating amount is less than 0.2 / m ² , a uniform gas barrier layer cannot be formed, and there is a problem that sufficient gas barrier properties cannot be obtained. On the other hand, when it is more than 10 g / m ² , the drying load at the time of coating increases, which is not preferable from the viewpoints of both operation and cost.

As the gas barrier property of the gas barrier layer of the present invention, the oxygen permeation amount under a dry condition of 23 ° C.-0% RH is 10 ml / m ² · day or less, and the high humidity condition is 23 ° C.-85% RH. It is preferable that the oxygen permeation amount is 500 ml / m ² · day or less. More preferably, the oxygen permeation amount under dry conditions is 5 ml / m ² · day or less, and the oxygen permeation amount under high humidity conditions is 350 ml / m ² · day or less.
In the embodiment of the present invention, the oxygen permeation amount is 0.5 to 2.0 ml / m ² · day under the dry condition of 23 ° C.-0% RH and the high humidity condition of 23 ° C.-85% RH. The oxygen permeation amount is 65 to 330 ml / m ² · day, and by using the paper barrier packaging material having the gas barrier layer of the present invention, the package is protected from deterioration due to gas such as oxidation. Can do.

  In the present invention, a sealant layer such as polyethylene, polypropylene, and polyvinyl acetate polymer 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 a known method such as a conventional melt extrusion laminating method, a dry laminating method using a film, or a direct melt coating method can be used.

  EXAMPLES The present invention will be specifically described below with reference to examples, but of course not limited to these examples. In addition, unless otherwise indicated, the part and% in an example show a weight part and weight%, respectively. In addition, it tested based on the evaluation methods as shown below about a coating liquid and the obtained packaging material. The test results are shown in the table.

(Evaluation method)
(1) Water vapor permeability: Measured using a moisture permeability measuring instrument (Dr. Lyssy, L80-4000) under conditions of a temperature of 40 ± 0.5 ° C. and a relative humidity of 90 ± 2%.
(2) Oxygen permeability: OX-TRAN 2/21 manufactured by MOCON was used and measured under conditions of 23 ° C.-0% RH and 23 ° C.-85% RH.
(3) Contact angle: Surface contact 0.1 seconds after dropping a water drop using a dynamic surface contact angle measuring device (Fibro, Dynamic Absorption Tester DAT1100) in an atmosphere of 23 ° C. and 50% RH. The corner was measured.
(4) Average particle size: The sample slurry was dropped and mixed in pure water to which 0.2% by weight of sodium hexametaphosphate was added as a dispersant to form a uniform dispersion, and a laser particle size measuring instrument (equipment used: Malvern, Inc.) The volume average particle size was measured using Mastersizer S type.
(5) Aspect ratio: The plane direction and the cross-sectional direction of the pigment were photographed using an SEM (scanning electron microscope), and the diameter and thickness of the pigment orientation surface were measured. / Thickness].
(6) Average fiber length: The fiber length was measured from an atomic force microscope image of cellulose nanofibers fixed on a mica slice, 100 randomly selected fibers were measured, and the average fiber length was calculated. Fiber length measurement was performed in a range using image analysis software WinROOF (Mitani Corporation).
(7) Average fiber width: The height in the Z-axis direction was determined from the fiber image obtained by observation using PC software “Spisel32” for a scanning probe microscope (SPI3800N / SPA400: SII, manufactured by NanoTechnology). The fiber width was measured. 20 fiber widths were measured, and the arithmetic average value was defined as the average fiber width.

(Production of anion-modified cellulose: carboxymethylation (C1))
To a stirrer that can mix pulp, add 250 g of pulp (NBKP, Nippon Paper Industries Co., Ltd.) by dry mass and 67 g of sodium hydroxide by dry mass, and add water so that the pulp solid concentration is 40%. It was. Then, after stirring for 30 minutes at 30 ° C., the temperature was raised to 70 ° C., and 127 g (in terms of active ingredient) of sodium monochloroacetate was added. After reacting for 1 hour, the reaction product was taken out, neutralized and washed to obtain an anion-modified cellulose (cellulose into which a carboxymethyl group was introduced) having a carboxymethyl substitution degree of 0.25 per glucose unit.
(Preparation of anion-modified cellulose nanofiber dispersion)
The anion-modified cellulose was adjusted to 1.0% (w / v), treated with an ultra-high pressure homogenizer (20 ° C., 140 MPa) three times, and an anion-modified cellulose nanofiber (carboxymethylated cellulose nanofiber) dispersion ( C1) was obtained.
The average fiber length of the carboxymethylated cellulose nanofibers in the obtained dispersion was 860 nm, and the average fiber width was 26 nm.

(Production of anion-modified cellulose pulp: carboxymethylation (C2))
An anion-modified cellulose nanofiber (carboxymethylated cellulose nanofiber) dispersion (C2) was obtained in the same manner as C1, except that the number of treatments with the ultrahigh pressure homogenizer was 10.
The average fiber length of the carboxymethylated cellulose nanofibers in the obtained dispersion was 320 nm, and the average fiber width was 6 nm.

(Production of anion-modified cellulose pulp: carboxymethylation (C3))
To a stirrer that can mix pulp, add 200 g of pulp (NBKP, manufactured by Nippon Paper Industries Co., Ltd.) and 50 g of sodium hydroxide by dry mass, and add water so that the pulp solid concentration is 20%. It was. Then, after stirring for 30 minutes at 30 ° C., the temperature was raised to 70 ° C., and 50 g of sodium monochloroacetate (in terms of active ingredient) was added. After reacting for 1 hour, the reaction product was taken out, neutralized and washed to obtain an anion-modified cellulose (cellulose having a carboxymethyl group introduced) having a carboxymethyl substitution degree of 0.05 per glucose unit.
(Preparation of anion-modified cellulose nanofiber dispersion)
The anion-modified cellulose was adjusted to 1.0% (w / v), treated with an ultra-high pressure homogenizer (20 ° C., 140 MPa) three times, and an anion-modified cellulose nanofiber (carboxymethylated cellulose nanofiber) dispersion ( C3) was obtained.
The average fiber length of the carboxymethylated cellulose nanofiber dispersion in the obtained dispersion was 4500 nm, and the average fiber width was 28 nm.

(Production of anion-modified cellulose pulp: carboxymethylation (C4))
An anion-modified cellulose nanofiber (carboxymethylated cellulose nanofiber) dispersion C4 was obtained in the same manner as C3, except that the number of treatments with the ultrahigh pressure homogenizer was 10.
The average fiber length of carboxymethylated cellulose nanofibers in the obtained dispersion was 1300 nm, and the average fiber width was 10 nm.

(Manufacture of anion-modified pulp: carboxylation (T1))
500 g of bleached unbeaten kraft pulp (whiteness 85%) derived from coniferous trees (absolutely dried) is added to 500 ml of an aqueous solution in which 780 mg of TEMPO (Sigma Aldrich) and 75.5 g of sodium bromide are dissolved, and the pulp is uniformly dispersed. Until stirred. An aqueous sodium hypochlorite solution was added to the reaction system to 6.0 mmol / g to initiate the oxidation reaction. During the reaction, the pH in the system was lowered, but a 3M sodium hydroxide aqueous solution was sequentially added to adjust the pH to 10. The reaction was terminated when sodium hypochlorite was consumed and the pH in the system no longer changed. The mixture after the reaction was filtered through a glass filter to separate the pulp, and the pulp was sufficiently washed with water to obtain an anion-modified pulp (pulp introduced with a carboxyl group). The pulp yield at this time was 90%, and the time required for the oxidation reaction was 90 minutes. The amount of carboxyl groups of this anion-modified pulp was 1.6 mmol / g.
(Preparation of anion-modified cellulose nanofiber dispersion)
The anion-modified pulp was adjusted to 1.0% (w / v), treated 10 times with an ultra-high pressure homogenizer (20 ° C., 140 MPa), and an anion-modified cellulose nanofiber (carboxylated cellulose nanofiber) dispersion (T1 )
The average fiber length of carboxylated cellulose nanofibers in the obtained dispersion was 350 nm, and the average fiber width was 4 nm.

(Manufacture of anion-modified pulp: carboxylation (T2))
An anion-modified cellulose nanofiber (carboxylated cellulose nanofiber) dispersion (T2) was obtained in the same manner as T1, except that the number of treatments with the ultra-high pressure homogenizer was three.
The average fiber length of carboxylated cellulose nanofibers in the obtained dispersion was 510 nm, and the average fiber width was 8 nm.

(Manufacture of anion-modified pulp: carboxylation (T3))
500 g of bleached unbeaten kraft pulp (whiteness 85%) derived from coniferous trees (absolutely dried) is added to 500 ml of an aqueous solution in which 780 mg of TEMPO (Sigma Aldrich) and 75.5 g of sodium bromide are dissolved, and the pulp is uniformly dispersed. Until stirred. An aqueous sodium hypochlorite solution was added to the reaction system to 4.0 mmol / g to initiate the oxidation reaction. During the reaction, the pH in the system was lowered, but a 3M sodium hydroxide aqueous solution was sequentially added to adjust the pH to 10. The reaction was terminated when sodium hypochlorite was consumed and the pH in the system no longer changed. The mixture after the reaction was filtered through a glass filter to separate the pulp, and the pulp was sufficiently washed with water to obtain an anion-modified pulp (pulp introduced with a carboxyl group). The pulp yield at this time was 90%, and the time required for the oxidation reaction was 90 minutes. The amount of carboxyl groups of this anion-modified pulp was 1.2 mmol / g.
(Preparation of anion-modified cellulose nanofiber dispersion)
The anion-modified oxidized pulp was adjusted to 1.0% (w / v), treated with an ultra-high pressure homogenizer (20 ° C., 140 MPa) 10 times, and an anion-modified cellulose nanofiber (carboxylated cellulose nanofiber) dispersion ( T3) was obtained.
The average fiber length of the carboxylated cellulose nanofiber dispersion in the obtained dispersion was 430 nm, and the average fiber width was 7 nm.

(Manufacture of anion-modified pulp: carboxylation (T4))
An anion-modified cellulose nanofiber (carboxylated cellulose nanofiber) dispersion T4 was obtained in the same manner as T3 except that the number of times of treatment with the ultrahigh pressure homogenizer was changed to 3.
The average fiber length of carboxylated cellulose nanofibers in the obtained dispersion was 670 nm, and the average fiber width was 12 nm.

[Example 1]
(Preparation of paper substrate)
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 obtain raw pulp. In the raw pulp slurry, polyacrylamide (PAM) having a molecular weight of 2.5 million as a dry paper strength enhancer is 0.1% per dry pulp weight, and alkyl ketene dimer (AKD) as a sizing agent is 0. 35%, Polyamide epichlorohydrin (PAEH) resin as wet paper strength enhancer 0.15% per dry pulp weight, and polyacrylamide (PAM) with molecular weight of 10 million as dry agent After adding 0.08% per weight, paper was made at a speed of 300 m / min with a Duoformer FM paper machine to obtain a paper with a basis weight of 59 g / m ² . Next, polyvinyl alcohol (PVA117 manufactured by Kuraray Co., Ltd.) prepared to a solid content concentration of 2% on the obtained paper was coated with 1.0 g / m ^{2 on} both sides with a rod metering size press, dried, and a basis weight of 60 g / m. ^Two base papers were obtained. The obtained base paper was smoothed using a chilled calendar at a speed of 300 min / m and a linear pressure of 50 kgf / cm 1 pass.

(Preparation of coating solution for water vapor barrier layer)
The pigment large particle size engineered kaolin (Varisurf HX, manufactured by Imeris Co., Ltd., particle diameter 9.0 μm, aspect ratio 80-100), sodium polyacrylate as a dispersant, 0.2 part with respect to 100 parts of the pigment The slurry was added and dispersed with a serie mixer to prepare a slurry having a solid content of 55%. In the obtained slurry, a styrene-butadiene latex (PNT 7868 manufactured by Nippon Zeon Co., Ltd.) is blended so as to be 100 parts (solid content) with respect to 100 parts by weight of the pigment, and a coating liquid having a solid content concentration of 50%. A was obtained.

(Preparation of gas barrier layer coating solution)
Carboxymethylated cellulose nanofiber dispersion C1 (coating liquid B) obtained by the above treatment was used as a gas barrier layer coating liquid.

(Preparation of paper barrier packaging materials)
The coating liquid A is coated on the obtained base paper with a blade coater at a coating speed of 300 m / min so that the coating amount (dry) is 12 g / m ² and dried, and then the coating liquid is coated thereon. B was coated on one side using a roll coater at a coating speed of 300 m / min so that the coating amount (dry) was 2.0 g / m ² to obtain a paper barrier packaging material.

[Example 2]
5 ml of 1% (w / v) aqueous solution of potassium alum is added to 95 ml of carboxymethylated cellulose nanofiber dispersion (coating liquid B), and gently stirred with a stirrer for 2 hours to crosslink nanofibers. Agglomerates were obtained. The agglomerates were centrifuged at 5000 rpm for 15 minutes using a centrifuge and dehydrated. Thereafter, it was re-diluted to 200 ml with water, and centrifugation and dehydration were performed twice in the same manner. The obtained precipitate was adjusted to 0.3% (w / v), and the homogenizer was used except that the uniform dispersion obtained by stirring for 30 minutes at 3000 rpm was used as the gas barrier layer coating solution. In the same manner as in Example 1, a paper barrier packaging material was obtained.

[Example 3]
A paper barrier packaging material was obtained in the same manner as in Example 1, except that the coating liquid for gas barrier layer (coating liquid B) was changed to carboxylated cellulose nanofiber dispersion T1 (coating liquid C).

[Example 4]
5 ml of 1% (w / v) aqueous solution of potassium alum was added to 95 ml of the carboxylated cellulose nanofiber dispersion (coating liquid C), and gently stirred with a stirrer for 2 hours to form crosslinked nanofibers. Aggregates were obtained. The agglomerates were centrifuged at 5000 rpm for 15 minutes using a centrifuge and dehydrated. Thereafter, it was re-diluted to 200 ml with water, and centrifugation and dehydration were performed twice in the same manner. The obtained precipitate was adjusted to 0.3% (w / v), and the homogenizer was used except that the uniform dispersion obtained by stirring for 30 minutes at 3000 rpm was used as the gas barrier layer coating solution. A paper barrier packaging material was obtained in the same manner as in Example 1.

[Example 5]
0.2 parts of poly (sodium acrylate) as a dispersant is added to 100 parts of the pigment to a large particle size engineered kaolin (Imeris Co., Ltd. Varisurf HX), which is a pigment, and dispersed with a serie mixer to obtain a solid concentration of 55 % Slurry was prepared. A dispersion obtained by mixing the obtained slurry and the coating liquid B with a solid content of pigment: coating liquid B = 100: 100 so that the solid content concentration becomes 10% is used as the coating liquid for the gas barrier layer. A paper barrier packaging material was obtained in the same manner as in Example 1.

[Example 6]
A 5% (w / v) aqueous solution of potassium alum was blended in coating solution B so that the solid content was 3 parts with respect to carboxymethylated cellulose nanofibers, and the solid content concentration was adjusted to 1.0%. A paper barrier packaging material was obtained in the same manner as in Example 1 except that the dispersion was changed to a gas barrier layer coating solution.

[Example 7]
The slurry prepared in Example 5 was mixed with the coating liquid B so that the pigment: coating liquid B = 100: 100 in solid content, and a 5% (w / v) aqueous solution of potassium alum was carboxymethylated. A paper barrier packaging material was prepared in the same manner as in Example 1 except that a dispersion having a solid content of 10% blended with cellulose nanofibers to a solid content of 3 parts was used as the gas barrier layer coating solution. Obtained.

[Example 8]
As a coating solution for the water vapor barrier layer, a heavy calcium carbonate slurry (FMT-75, average particle size: 1.6 μm, aspect ratio: 1) manufactured by Phimatech Co., Ltd. is used in the pigment of the coating solution A. A paper barrier packaging material was obtained in the same manner as in Example 1 except that the coating solution was mixed and stirred so that the large particle size engineered kaolin: heavy calcium carbonate = 75: 25.

[Example 9]
Except that a 5% (w / v) aqueous solution of potassium alum was blended with the coating liquid A so as to be 3 parts with respect to the pigment, and a dispersion having a solid content concentration of 50% was used as the coating liquid for the water vapor barrier layer. In the same manner as in Example 1, a paper barrier packaging material was obtained.

[Example 10]
As in Example 1, except that the coating liquid obtained in Example 7 was used as the gas barrier layer coating liquid and the coating liquid obtained in Example 8 was used as the water vapor barrier layer coating liquid. Thus, a paper barrier packaging material was obtained.

[Example 11]
As in Example 1, except that the coating liquid obtained in Example 7 was used as the gas barrier layer coating liquid and the coating liquid obtained in Example 9 was used as the water vapor barrier layer coating liquid. Thus, a paper barrier packaging material was obtained.

[Example 12]
A paper barrier was prepared in the same manner as in Example 5 except that the large particle size engineered kaolin in the gas barrier layer coating solution of Example 5 was changed to mica (NTS-10 manufactured by Topy Industries, Ltd., particle size: 12 μm). A packaging material was obtained.

[Example 13]
Except for changing the large particle size engineered kaolin in the coating liquid for gas barrier layer of Example 5 to montmorillonite (Nikkanite A-36, manufactured by Toshin Kasei Co., Ltd., particle size: 400 μm), the same as in Example 5. A paper barrier packaging material was obtained.

[Example 14]
The large particle size engineered kaolin in the coating solution for the water vapor barrier layer of Example 1 was changed to mica (B-82, Matsuo Sangyo Co., Ltd., particle size: 180 μm), and the pigment dispersion concentration in the slurry was 20%. A paper barrier packaging material was obtained in the same manner as in Example 1 except that the coating liquid concentration was changed to 30% and the coating amount was changed to 9 g / m ² .

[Example 15]
The large particle size engineered kaolin in the coating solution for the water vapor barrier layer of Example 1 was changed to montmorillonite (Nikkanite A-36 manufactured by Toshin Kasei Co., Ltd., particle size: 400 μm), and the pigment dispersion concentration in the slurry was changed. A paper barrier packaging material was obtained in the same manner as in Example 1 except that the coating liquid concentration was changed to 20%, the coating liquid concentration was changed to 30%, and the coating amount was changed to 9 g / m ² .

[Example 16]
Made of paper in the same manner as in Example 1 except that the styrene-butadiene latex in the coating solution for the water vapor barrier layer of Example 1 was changed to an acrylic styrene copolymer emulsion (X-511-374E manufactured by Seiden Chemical Co., Ltd.). Barrier packaging material was obtained.

[Example 17]
The same procedure as in Example 1 was conducted except that the styrene / butadiene latex (PNT 7868 manufactured by Nippon Zeon Co., Ltd.) of the coating solution for the water vapor barrier layer in Example 1 was changed to styrene / butadiene latex (L7360 manufactured by Asahi Kasei Chemicals Corporation). A paper barrier packaging material was obtained.

[Example 18]
The large particle size engineered kaolin (Varisurf HX, manufactured by Imeris Corp.) in the coating solution for the water vapor barrier layer of Example 1 was converted into the large particle size engineered kaolin (Capim CC manufactured by Imeris Corp., particle size: 8.0 μm, aspect ratio). : 10-15) A paper barrier packaging material was obtained in the same manner as in Example 1 except for changing to 10-15.

[Example 19]
The large particle size engineered kaolin (Varisurf HX manufactured by Imeris Co., Ltd.) in the coating solution for the water vapor barrier layer of Example 1 was finely divided kaolin (Hydragloss manufactured by KaMin Co., average particle size: 0.3 μm, aspect ratio: 10 to 10). A paper barrier packaging material was obtained in the same manner as in Example 1 except for changing to 15).

[Example 20]
The large particle size engineered kaolin (Varisurf HX, manufactured by Imeris Co.) in the coating solution for the water vapor barrier layer of Example 1 is classified into secondary kaolin (KCS manufactured by Imeris Co., average particle size: 3.6 μm, aspect ratio: 10). ~ 15) A paper barrier packaging material was obtained in the same manner as in Example 1 except that the above was changed.

[Example 21]
The same procedure as in Example 1 was conducted except that the styrene / butadiene latex (PNT 7868 manufactured by Nippon Zeon Co., Ltd.) in the coating solution for the water vapor barrier layer of Example 1 was changed to a styrene / butadiene latex (PNT 7889 manufactured by Nippon Zeon Co., Ltd.). Thus, a paper barrier packaging material was obtained.

[Example 22]
A paper barrier packaging material in the same manner as in Example 1 except that the styrene-butadiene latex in the coating solution for the water vapor barrier layer in Example 1 was changed to an acrylic copolymer latex (E316 manufactured by Asahi Kasei Chemicals Corporation). Got.

[Example 23]
A paper barrier was prepared in the same manner as in Example 1 except that the styrene / butadiene latex in the coating solution for the water vapor barrier layer in Example 1 was changed to an acrylic copolymer aqueous emulsion (EK-61 manufactured by Seiden Chemical Co., Ltd.). A packaging material was obtained.

[Example 24]
A paper barrier packaging material was obtained in the same manner as in Example 1 except that the coating amount of the coating liquid A was changed from 12 g / m ² to 6 g / m ² in terms of dry weight.

[Example 25]
A paper barrier packaging material was obtained in the same manner as in Example 1 except that the coating amount of the coating liquid A was changed from 12 g / m ² to 15 g / m ² in terms of dry weight.

[Example 26]
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 27]
The coating amount of the coating liquid B, and dry weight of 2 g / m ² was changed to 3 g / m ² in the same manner as in Example 1 to obtain a paper barrier packaging materials.

[Example 28]
In the coating solution for water vapor barrier layer of Example 1, the same as Example 1 except that the blending amount of styrene / butadiene latex (PNT 7868 manufactured by Nippon Zeon Co., Ltd.) was changed from 100 parts to 50 parts (solid content) of the pigment. Thus, a paper barrier packaging material was obtained.

[Example 29]
In the coating solution for the water vapor barrier layer of Example 1, the same as in Example 1 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 (solid content) of the pigment. Thus, a paper barrier packaging material was obtained.

[Example 30]
In the gas barrier layer coating liquid of Example 5, the paper was prepared in the same manner as in Example 5 except that the blending amount of the kaolin slurry was changed so that the pigment: coating liquid B = 100: 100 to 150: 100 in terms of solid content. Barrier packaging material made was obtained.

[Example 31]
In the gas barrier layer coating solution of Example 5, the paper was prepared in the same manner as in Example 5 except that the blending amount of the kaolin slurry was changed from pigment: coating solution B = 100: 100 to 50: 100 in terms of solid content. Barrier packaging material made was obtained.

[Example 32]
In the coating solution for the water vapor barrier layer of Example 1, the same as Example 1 except that the blending amount of styrene / butadiene latex (PNT 7868 manufactured by Nippon Zeon Co., Ltd.) was changed from 100 parts to 35 parts (solid content) of the pigment. Thus, a paper barrier packaging material was obtained.

[Example 33]
As a coating solution for the water vapor barrier layer, a heavy calcium carbonate slurry (FMT-90, average particle size: 1.2 μm, aspect ratio: 1) manufactured by Phimatech Co., Ltd. in the pigment of the coating solution A is large in the pigment compounding ratio. Particle size engineered kaolin: heavy calcium carbonate = 50: 50 A paper barrier packaging material was obtained in the same manner as in Example 1 except that the coating liquid mixed and stirred was used.

[Example 34]
A heavy calcium carbonate slurry (Fmatec FMT-90) was mixed and stirred so that the pigment compounding ratio was large particle size engineered kaolin: heavy calcium carbonate = 90: 10. A paper barrier packaging material was obtained in the same manner as in Example 33.

[Example 35]
As a coating solution for the water vapor barrier layer, a heavy calcium carbonate slurry (FMT-65 manufactured by PMMA Tech, average particle size: 1.9 μm, aspect ratio: 1) in the pigment of the coating solution A is large in the pigment compounding ratio. Particle size engineered kaolin: heavy calcium carbonate = 90:10 A paper barrier packaging material was obtained in the same manner as in Example 1 except that the coating liquid mixed and stirred was used.

[Example 36]
A paper barrier packaging material was obtained in the same manner as in Example 1 except that the gas barrier layer coating solution (coating solution B) was changed to carboxymethylated cellulose nanofiber dispersion C2.

[Example 37]
A paper barrier packaging material was obtained in the same manner as in Example 1 except that the gas barrier layer coating solution (coating solution B) was changed to carboxymethylated cellulose nanofiber dispersion C3.

[Example 38]
A paper barrier packaging material was obtained in the same manner as in Example 1 except that the gas barrier layer coating solution (coating solution B) was changed to a carboxymethylated cellulose nanofiber dispersion.

[Example 39]
A paper barrier packaging material was obtained in the same manner as in Example 1 except that the coating liquid for gas barrier layer (coating liquid B) was changed to carboxylated cellulose nanofiber dispersion T2.

[Example 40]
A paper barrier packaging material was obtained in the same manner as in Example 1 except that the coating liquid for gas barrier layer (coating liquid B) was changed to carboxylated cellulose nanofiber dispersion T3.

[Example 41]
A paper barrier packaging material was obtained in the same manner as in Example 1 except that the coating liquid for gas barrier layer (coating liquid B) was changed to carboxylated cellulose nanofiber dispersion T4.

[Example 42]
The gas barrier layer coating solution (coating solution B) was prepared by mixing carboxymethylated cellulose nanofibers and polyvinyl alcohol 10% aqueous solution (Kuraray Co., Ltd., PVA117) to a dry weight ratio of 80/20. A paper-based barrier packaging material was obtained in the same manner as in Example 1 except that.

[Example 43]
The gas barrier layer coating solution (coating solution B) was prepared by mixing carboxymethylated cellulose nanofibers and a 10% aqueous solution of polyvinyl alcohol (Kuraray Co., Ltd., PVA117) to a dry weight ratio of 50/50. A paper-based barrier packaging material was obtained in the same manner as in Example 1 except that.

[ Reference Example 44]
The coating solution for gas barrier layer (coating solution B) is a dry weight ratio of carboxymethylated cellulose nanofiber and 10% aqueous solution of polyvinyl alcohol (Kuraray Co., PVA117).
A paper-based barrier packaging material was obtained in the same manner as in Example 1 except that the mixture was used so as to be / 80.

[Example 45]
To the coating solution for gas barrier layer of Example 43, the large particle size engineered kaolin dispersion, which is the pigment used in the coating solution for water vapor barrier layer of Example 1, was dried at a weight ratio of carboxymethylated cellulose nanofibers. A paper-based barrier packaging material was obtained in the same manner as in Example 43, except that / polyvinyl alcohol / pigment = 50/50/100.

[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.

Claims (12)

A paper barrier packaging material provided with a plurality of coating layers on a paper substrate,
The plurality of coating layers include a water vapor barrier layer containing a binder resin formed on a paper substrate, a gas barrier layer formed on the water vapor barrier layer,
The paper barrier packaging material, wherein the gas barrier layer contains anion-modified cellulose nanofibers and does not contain a binder resin . A paper barrier packaging material provided with a plurality of coating layers on a paper substrate,
The plurality of coating layers include a water vapor barrier layer containing a binder resin formed on a paper substrate, a gas barrier layer formed on the water vapor barrier layer,
The gas barrier layer contains anion-modified cellulose nanofibers and a binder resin , and the blending ratio (dry weight ratio) is anion-modified cellulose nanofiber / binder resin = 50/50 to 99/1 . Barrier packaging material. The paper barrier packaging material according to claim 1 or 2 , wherein the anion-modified cellulose nanofiber has an average fiber width of 1 to 1000 nm and an average fiber length of 50 to 10,000 nm. The anion-modified cellulose nanofiber is a cellulose nanofiber having a carboxymethyl group introduced therein, wherein the degree of substitution of carboxymethyl group per glucose unit of cellulose is 0.01 to 0.50. The laminated body in any one of -3 . The anion-modified cellulose nanofiber is a cellulose nanofiber introduced with a carboxyl group, and the amount of carboxyl group is 0.5 mmol / g to 2.0 mmol / with respect to the absolute dry mass of the cellulose nanofiber introduced with a carboxyl group. It is g, The laminated body in any one of Claims 1-3 characterized by the above-mentioned. The paper barrier packaging material according to any one of claims 1 to 5 , wherein the binder resin of the water vapor barrier layer is a styrene / butadiene synthetic resin. The paper vapor barrier packaging material according to any one of claims 1 to 6 , wherein the water vapor barrier layer contains kaolin having an average particle diameter of 5 µm or more and an aspect ratio of 10 or more. The water vapor barrier layer is paper barrier packaging material according to any one of claims 1 to 7, characterized in that it contains the following pigments average particle size 5 [mu] m. The paper barrier packaging material according to any one of claims 1 to 8 , wherein the water vapor barrier layer contains a crosslinking agent. The gas barrier layer has an average particle diameter of 5μm or more, paper barrier packaging material according to any one of claims 1 to 9, characterized in that it contains an aspect ratio of 10 or more inorganic pigments. The gas barrier layer paper barrier packaging material according to any one of claims 1 to 10, characterized by containing a crosslinking agent. Of claim 1 to 11 in which the coating amount of the water vapor barrier layer coating weight of 4~30g / ^{m 2,} the gas barrier layer by dry weight, wherein the dry weight is 0.2 to 10 g / ^{m 2} The paper barrier packaging material according to any one of the above.