JP2010120645A - Moisture resistant corrugated fiberboard box - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a moisture resistant corrugated fiberboard box having excellent moisture resistance in which an object to be stored is stored in a storage space ensuring the moisture resistance. <P>SOLUTION: The moisture resistant corrugated fiberboard box is formed by using a corrugated fiberboard laminate in which a vapor-deposited plastic film 14 having at least a vapor-deposited thin film layer 12 of a metal or a metal oxide, and a heat-dried coating film of a thin film consisting of a mixture solution of a silicon compound expressed as Si(OR<SP>1</SP>)<SB>4</SB>and R<SP>2</SP>Si(OR<SP>3</SP>)<SB>3</SB>(where OR<SP>1</SP>and OR<SP>3</SP>each denote a hydrolyzable group, and R<SP>2</SP>denotes an organic functional group) or its hydrolysate, and a water-soluble polymer having hydroxyl groups is laminated at least on one side of the corrugated fiberboard. The vapor-deposited plastic film lamination side is located on the inner surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a moisture-proof corrugated cardboard box that is excellent in moisture-proof property and that can store a stored item in a storage space in which the moisture-proof property is secured.

  Usually, paper such as paperboard and cardboard is breathable and not moisture-proof. Therefore, a paper box or a cardboard box made using such paper cannot secure moisture resistance in its storage space.

  There are various types of stored items stored in paper boxes and cardboard boxes, and many of them are required to be stored in an environment in which moisture resistance is ensured.

  In order to cope with such a situation, corrugated cardboard is made of moisture-proof paper, a method of laminating a polyethylene film (see, for example, Patent Document 1), a corrugated cardboard having a large number of stages, or a biodegradable layer (PLA layer) is provided. Methods (see, for example, Patent Document 2) have been proposed, and various attempts have been made to ensure moisture resistance.

However, the corrugated cardboard box according to such a proposal cannot secure satisfactory moisture resistance, and development of a cardboard box in which better moisture resistance can be secured in the storage space is strongly desired.
Registered Utility Model No. 3130190 Registered Utility Model No. 3132777

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a moisture-proof corrugated cardboard box that is excellent in moisture-proof property and can store stored items in a storage space in which moisture-proof properties are ensured. .

In order to solve the above-mentioned problems, the invention according to claim 1 is a metal or metal oxide vapor-deposited thin film layer, and Si (OR ¹ ) ₄ and R ² Si (OR ³ ) ₃ (OR ¹ , OR ³ is a hydrolyzable group, R ² is an organic functional group) or a hydrolyzed product thereof and a heat-dried film of a thin film comprising a solution in which a water-soluble polymer having a hydroxyl group is mixed. A moisture-proof corrugated cardboard box using a corrugated cardboard laminate in which a vapor-deposited plastic film is laminated on at least one side of the corrugated cardboard, and having the vapor-deposited plastic film laminated side positioned on the inner surface. is there.

  The invention according to claim 2 is the moisture-proof corrugated cardboard box according to claim 1, wherein the thickness of the vapor-deposited thin film layer of metal or metal oxide of the vapor-deposited plastic film is 5 to 100 nm.

  Furthermore, the invention according to claim 3 is the moisture-proof cardboard box according to claim 1 or 2, characterized in that a plastic film is further laminated on the vapor-deposited plastic film.

Furthermore, the invention according to claim 4 is characterized in that in the moisture-proof corrugated cardboard box according to any one of claims 1 to 3, it is sealed with a sealing tape having at least a deposited thin film layer of metal or metal oxide. To do.

According to the present invention, a deposited thin film layer of metal or metal oxide, Si (OR ¹ ) ₄ and R ² Si (OR ³ ) ₃ (OR ¹ and OR ³ are hydrolyzable groups, and R ² is an organic functional group. A vapor-deposited plastic film having at least a thin film heat-dried film made of a solution in which a silicon compound or a hydrolyzate thereof represented by formula (1) is mixed with a water-soluble polymer having a hydroxyl group is laminated on at least one side of the cardboard. Using a laminated body and boxed with its vapor-deposited plastic film laminated side positioned on the inner surface, excellent moisture resistance can be ensured, and deterioration of the items stored in the storage space due to moisture absorption is ensured. Can be prevented.

  Hereinafter, the present invention will be described in detail with reference to the drawings. 1 to 3 show a schematic cross-sectional configuration of a corrugated board laminate constituting the moisture-proof corrugated cardboard box of the present invention.

A corrugated board laminate 10 shown in FIG. 1 has a vapor-deposited thin film layer 12 made of a metal or a metal oxide, Si (OR ¹ ) ₄ and R ² Si (OR ³ ) ₃ ( OR ¹ , OR ³ are hydrolyzable groups, R ² is an organic functional group) and a heat-dried film of a thin film comprising a solution in which a silicon compound or a hydrolyzate thereof and a water-soluble polymer having a hydroxyl group are mixed. A vapor-deposited plastic film 14 in which a certain gas barrier coating layer 13 is sequentially laminated is laminated on one side of a cardboard 15.

On the other hand, a corrugated board laminate 20 shown in FIG. 2 has a vapor-deposited thin film layer 22 made of a metal or metal oxide, Si (OR ¹ ) ₄ and R ² Si (OR ³ ) on one surface of a plastic film substrate 21. Heat drying of a thin film comprising a solution in which a silicon compound represented by ₃ (OR ¹ , OR ³ is a hydrolyzable group, R ² is an organic functional group) or a hydrolyzate thereof and a water-soluble polymer having a hydroxyl group is mixed. A vapor-deposited plastic film 24 in which a gas barrier coating layer 23 that is a coating is sequentially laminated is laminated on one side of a corrugated cardboard 25 via a plastic film 26.

A corrugated board laminate 30 shown in FIG. 3 has a vapor-deposited thin film layer 32 made of metal or metal oxide, Si (OR ¹ ) ₄ and R ² Si (OR ³ ) on one surface of a plastic film substrate 31. Heat drying of a thin film comprising a solution in which a silicon compound represented by ₃ (OR ¹ , OR ³ is a hydrolyzable group, R ² is an organic functional group) or a hydrolyzate thereof and a water-soluble polymer having a hydroxyl group is mixed. A vapor-deposited plastic film 34 formed by sequentially laminating a gas-barrier film layer 33 that is a film is laminated so that the plastic film substrate 31 is in contact with one surface of the corrugated cardboard 35, and the gas-barrier film layer 33 of the vapor-deposited plastic film 34 is further laminated. A plastic film 36 is further laminated thereon.

  The moisture-proof cardboard box of the present invention is obtained by using the corrugated cardboard laminates 10, 20, and 30 having such a configuration and making the box so that the laminated plastic films 14, 24, and 34 are positioned on the inner surface. be able to.

  FIG. 4 shows a moisture-proof cardboard box 40 thus obtained and a state in which the moisture-proof cardboard box 40 is sealed with a moisture-proof sealing tape 41 having a deposited thin film layer of metal or metal oxide. Yes.

  The plastic film bases 11, 21, and 31 constituting the vapor-deposited plastic films 14, 24, and 34 are preferably transparent in order to make use of the transparency of the vapor-deposited thin film layers 12, 22, and 32 described later. Specifically, a polyester film made of polyethylene terephthalate or polyethylene naphthalate, a polyolefin film made of polyethylene or polypropylene, a polystyrene film, a polyamide film, a polyvinyl chloride film, a polycarbonate film, a polyacrylonitrile film, a polyimide film, a polylactic acid Examples thereof include biodegradable plastic films such as films. These may be stretched or unstretched, but those excellent in mechanical strength and dimensional stability are preferred. In these, the polyethylene terephthalate film arbitrarily extended | stretched to biaxial direction from surfaces, such as heat resistance, is used preferably. Further, a thin film made of various known additives and stabilizers such as an antistatic agent, an ultraviolet ray preventing agent, a plasticizer, and a lubricant may be provided on the surface of the plastic film substrate 11, 21, or 31. In order to improve adhesion to the thin film, corona treatment, low temperature plasma treatment, ion bombardment treatment, chemical treatment, solvent treatment, etc. may be performed as pretreatment.

  Furthermore, examples of the polyester film used as the plastic film base material 11, 21, 31 include terephthalic acid, naphthalenecarboxylic acid, isophthalic acid, diphenyldicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenoxy as dicarboxylic acid components constituting the polyester film. Ethane dicarboxylic acid, 5-sodium sulfoisophthalic acid, aromatic dicarboxylic acid such as phthalic acid, alicyclic dicarboxylic acid such as cyclohexyne dicarboxylic acid, oxalic acid, oxalic acid, adipic acid, sebacic acid, dimer acid, maleic acid, Examples thereof include aliphatic dicarboxylic acids such as fumaric acid and oxycarboxylic acids such as p-oxybenzoic acid. In addition, as an alcohol component, aliphatic glycols such as ethylene glycol, propanediol, 1,4 butanediol, 1,6 hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,4 cyclohexanedimethanol And those having aromatic glycols such as polyoxyalkylene glycol, bisphenol A, bisphenol S, and derivatives thereof.

  Among polyesters having such components, those mainly composed of polyethylene terephthalate are preferably used in consideration of film forming properties such as biaxial stretching properties, humidity properties, heat resistance, chemical resistance, and low cost. . In addition, within the range where various physical properties of polyethylene terephthalate can be maintained, other alcohol components are controlled so as to be incorporated into the main chain at the polymerization stage, and copolymerization is performed, so that a segment with a small rotational hindrance in the molecular chain (soft segment) ), The force generated by external impact and bending is absorbed by the soft segment in the molecular chain, and is excellent in impact resistance and flexibility. Furthermore, a copolyester in which 50 mol% or more of each of the carboxylic acid component and the alcohol component of the polyester is terephthalic acid, ethylene glycol, and derivatives thereof is also preferably used.

  The thickness of these plastic film substrates 11, 21, and 31 is preferably 1 μm or more. More specifically, suitability as a corrugated board laminate constituting a corrugated board box, and there are cases where other layers are laminated, and vapor-deposited thin film layers 12 and 22 made of metal or metal oxide, which will be described later, In consideration of workability in the case of laminating 32 and gas barrier coating layers 13, 23, 33, a thickness of about 5 to 200 μm is preferable in practice. Moreover, considering the mass productivity related to the manufacture of the vapor-deposited plastic film, it is desirable to make it long so that each layer can be formed continuously.

In order to improve the adhesion between the plastic film substrates 11, 21, 31 and the vapor-deposited thin film layers 12, 22, 32 made of a metal or metal oxide, which will be described later, a plastic film base is used by using radicals or ions. It is desirable to provide functional groups on the surfaces of the materials 11, 21, and 31, or to ion-etch the surfaces to physically scatter impurities or smooth the surfaces. As a result, the adhesion between the plastic film bases 11, 21, 31 and the vapor-deposited thin film layers 12, 22, 32 made of metal or metal oxide can be enhanced, and the gas barrier property and moisture-proof property can be improved. Generation of cracks in the layer can be prevented.

  On the other hand, the deposited thin film layers 12, 22, and 32 made of metal or metal oxide are formed of metal, such as aluminum, copper, silver, or metal oxide, such as yttrium tantalum oxide, aluminum oxide, silicon oxide, magnesium oxide, or the like. Any layer may be used as long as it is made of a vapor-deposited thin film such as a mixture and exhibits excellent gas barrier properties against oxygen, water vapor, and the like.

  The thickness of the vapor-deposited thin film layers 12, 22, and 32 made of metal or metal oxide is preferably in the range of about 5 to 300 nm. If the thickness is less than 5 nm, a uniform film may not be obtained, or the film thickness may not be sufficient, and the function as a gas barrier layer may not be sufficiently achieved. When the thickness exceeds 300 nm, it is difficult to maintain flexibility in the thin film, and there is a possibility that the thin film may be cracked by bending or pulling applied after the film formation. More preferably, the thickness may be about 5 to 100 nm.

  As a method of forming the vapor deposition thin film layers 12, 22, and 32 made of such metal or metal oxide on the plastic film base materials 11, 21, and 31, a normal vacuum vapor deposition method or other thin film formation methods can be used. A certain sputtering method, an ion plating method, a plasma vapor deposition method (CVD), etc. can be mentioned. However, considering productivity, the vacuum deposition method is the best at present. As a heating means of the vacuum evaporation apparatus used at this time, an electron beam heating method, a resistance heating method, an induction heating method, or the like is preferable. Further, in order to improve the adhesion between the thin film and the substrate and the denseness of the thin film, a plasma assist method or an ion beam assist method can be used. In addition, in order to change the quality of the deposited thin film, it is possible to perform reactive deposition by blowing oxygen gas or the like during deposition.

  On the other hand, the gas barrier coating layers 13, 23, 33 are provided with vapor deposited thin film layers 12, 22 made of metal or metal oxide in order to give higher gas barrier properties and to physically protect the deposited thin film layer. , 32.

In order to achieve such an object, the gas barrier coating layers 13, 23 and 33 are made of Si (OR ¹ ) ₄ and R ² Si (OR ³ ) ₃ (R ¹ and R ³ are CH ₃ , C ₂ H _{5, respectively).} From a solution (coating solution) in which a silicon compound represented by a hydrolyzable group such as C ₂ H ₄ OCH ₃ , R ² is an organic functional group) or a hydrolyzate thereof, and a water-soluble polymer having a hydroxyl group are mixed. It is set as the heat-drying film of the thin film which becomes. Hereinafter, each component contained in the coating liquid will be described.

In the silicon compound represented by R ² Si (OR ³ ) ₃ , R ³ is a hydrolyzable group such as CH ₃ , C ₂ H ₅ , C ₂ H ₄ OCH ₃ , and R ² is an organic functional group. In general, it is used as a silane coupling agent to improve the adhesion between the organic layer and the inorganic layer. The vapor-deposited plastic film having the above structure is also used as a constituent material of the gas barrier coating layer in order to improve the adhesion between the vapor-deposited thin film layer made of metal or metal oxide and the gas barrier coating layer. Among them, the organic functional group (R ² ) having a non-aqueous functional group such as a vinyl group, an epoxy group, a ureido group, or an isocyanate group is non-aqueous, so that the resistance to hot water is increased and the isocyanate group is polymerized. Isocyanurate is easy to handle in a gas barrier coating solution, slows the gelation of the coating solution, and can improve adhesion without causing a decrease in gas barrier properties due to the addition of a silane coupling agent. Are particularly preferably used.

The hydrolyzable group described above is a group that can be converted to a hydroxyl group by reacting with water under acidic, basic or neutral conditions. For example, an alkoxy group, an aryloxy group, a halogen atom , Acetoxy group, isocyanate group, hydroxyl group and the like. Of these, alkoxy groups are preferably used from the viewpoint of coating solution stability and the like. Among the alkoxy groups, lower alkoxy groups having 1 to 5 carbon atoms are more preferable. These alkoxy groups may be chain-like or branched, and a hydrogen atom may be substituted with a fluorine atom or the like. More preferred are a methoxy group and an ethoxy group.

  The isocyanurate refers to a product in which three isocyanate groups are polymerized to form a ring. Examples of the isocyanurate used in the coating liquid described above include those in which three isocyanate group-containing silanes are polymerized in a cyclic manner.

  The water-soluble polymer having a hydroxyl group refers to polyvinyl alcohol, starch, and celluloses. In particular, when polyvinyl alcohol (hereinafter referred to as PVA) is used as a component of the coating liquid, the gas barrier property is most excellent. PVA as used herein is generally obtained by saponifying polyvinyl acetate, and saponification is complete saponification in which only several percent of acetic acid groups remain from so-called partially saponified PVA in which several tens of percent of acetic acid groups remain. Includes up to PVA.

The coating liquid constituting the gas barrier coating layers 13, 23, 33 is, for example, a mixture of hydrolyzed Si (OR ¹ ) ₄ and a water-soluble polymer having a hydroxyl group, R ² Si (OR ³ ) ₃ in any order. However, the method of adding Si (OR ¹ ) ₄ and R ² Si (OR ³ ) ₃ to the water-soluble polymer after hydrolyzing them separately is the finest of SiO ₂ . This is a desirable method in consideration of dispersion and hydrolysis efficiency of Si (OR ¹ ) ₄ .

  In order to give such coating liquid adhesion, wettability with ink and adhesive, and prevention of cracking due to shrinkage, etc., clay compounds such as isocyanate compounds, colloidal silica and smectite, stabilizers, coloring Known additives such as agents and viscosity modifiers can be added within a range that does not impair the development of gas barrier properties and water resistance.

  The thickness of the thin film made of such a coating solution after heating and drying is not particularly limited, but cracks are likely to occur when the thickness exceeds 50 μm, so the thickness should be about 0.01 to 50 μm. Is desirable.

  Examples of the method for forming the gas barrier coating layer include a dipping method, a roll coating method, a gravure coating method, a reverse coating method, an air knife coating method, a comma coating method, a die coating method, a screen printing method, a spray coating method, and a gravure offset printing method. Can be used. After forming a thin film made of the coating liquid on the vapor-deposited thin film layer using these thin film forming methods, the gas barrier coating layer may be provided by heating and drying.

  As the heat drying method at this time, hot air drying, hot roll drying, high frequency irradiation drying, infrared irradiation drying, UV irradiation drying, or the like can be employed. Heat may be applied to the thin film made of the coating liquid by these heat drying methods, and water film may be blown off to heat dry the thin film. Also, two or more of these drying methods may be combined.

  When the heat applied to the surface of the thin film is a high temperature of 200 ° C. or higher, the gas barrier property of the resulting gas barrier coating layer is further improved, and the moisture resistance and water resistance are also improved. By performing the heat treatment at 200 ° C. or higher, even if the liquid content acts on the gas barrier coating layer or the gas barrier coating layer is placed in a high temperature environment, the gas barrier coating layer does not deteriorate, High barrier properties and adhesion can be maintained. This is because the condensation of the hydrolyzed metal alkoxide contained in the gas barrier coating layer proceeds and the water-soluble polymer is sufficiently dehydrated by the high temperature treatment.

  As a high-temperature heat treatment method at 200 ° C. or higher, a general hot air drying method or hot roll drying method may be used. A similar effect can be obtained by a flame treatment method in which the gas barrier coating surface is heat-treated with a flame of several thousand degrees.

  The corrugated cardboard laminates 10, 20, and 30 constituting the moisture-proof corrugated cardboard box of the present invention are obtained by laminating the vapor-deposited plastic films 14, 24, and 34 configured as described above on at least one side of the cardboards 15, 25, and 35. (See FIGS. 1 to 3).

  In general, corrugated cardboard is formed by combining a sheet of paper positioned on the front and back sides called “liner” and a corrugated portion giving a step called “medium shin”. The type of corrugated cardboard is determined by the combination of “liner” and “medium shin”, and the thickness and strength vary depending on the number of flutes and how they are stacked, but the vapor-deposited plastic films 14, 24, and 34 are laminated. Any of the cardboards 15, 25, and 35 can be used.

  The adhesive for bonding the vapor-deposited plastic films 14, 24, 34 to such cardboards 15, 25, 35 is not particularly limited. Yes, polyurethane resin (solvent / emulsion) adhesive, ethylene-vinyl acetate copolymer (EVA) resin emulsion adhesive, acrylic resin emulsion adhesive, α-olefin adhesive that can be coated by gravure coating method Etc. can be used as appropriate.

  In addition, when laminating the vapor-deposited plastic film, for the purpose of physical protection of the vapor-deposited plastic film metal or metal oxide vapor-deposited thin film layer or imparting mechanical suitability, as described above, in addition to the corrugated board 15, 25, 35, One or more plastic films 26 and 36 may be bonded together (see FIGS. 2 and 3).

  As the plastic films 26 and 36 used for the bonding, for example, a polyester film made of polyethylene terephthalate or polyethylene naphthalate, a polyolefin film made of polyethylene or polypropylene, a polystyrene film, a polyamide film, a polyvinyl chloride film, a polycarbonate film, a poly A biodegradable plastic film such as an acrylonitrile film, a polyimide film, or a polylactic acid film is used. These may be stretched or unstretched. Also melted by heat and fused to each other, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-ethyl acrylate copolymer Polyolefin resins such as polymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-propylene copolymer, methylpentene polymer, polyethylene or polypropylene, acrylic acid, methacrylic acid, maleic acid, maleic anhydride A film made of a resin such as an acid-modified polyolefin resin modified with an unsaturated carboxylic acid such as fumaric acid or itaconic acid can also be used. The thickness is appropriately determined depending on the use, but is preferably about 10 to 100 μm.

  Such plastic films 26 and 36 may be laminated on, for example, a vapor-deposited plastic film) and further bonded to one side of the cardboards 25 and 35 to form a corrugated board laminate.

  The moisture-proof corrugated cardboard box of the present invention is obtained by using a corrugated cardboard laminate having the above-described configuration and box-producing it. FIG. 4 shows a state in which the moisture-proof corrugated cardboard box 40 thus obtained is sealed with the sealing tape 41 as described above.

  In the moisture-proof corrugated cardboard box of the present invention, the stored items are stored in the storage space, and sealed with a sealing tape having at least a vapor-deposited thin film layer of metal or metal oxide, so that the moisture-proof property of the storage space can be ensured more reliably. Become.

  As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer of the sealing tape, known acrylic, polyester, vinyl acetate, rubber, and silicon pressure-sensitive adhesives can be used.

  In these, the acrylic adhesive which is excellent in heat resistance and a weather resistance is used preferably. Acrylic pressure-sensitive adhesive is a pressure-sensitive adhesive mainly composed of a copolymer of alkyl acrylate and acrylic acid, and a cross-linking agent, tackifier, plasticizer, filler, heat stabilizer, UV absorber, etc. An agent can be given as a more specific example.

  The crosslinking agent is used for improving the heat resistance and creep resistance of the pressure-sensitive adhesive layer. Specifically, it is a reactive crosslinking agent such as isocyanate, epoxy, aziridine, organometallic, chelate or amine, or a copolymer type crosslinking which is a polyfunctional vinyl monomer such as diacrylate or divinyl. Agents and the like. Furthermore, other subcomponents such as a tackifier and a plasticizer may be appropriately added according to the purpose.

  A known coating method may be used as a method of coating the adhesive with the sealing tape substrate. When forming the pressure-sensitive adhesive layer, a release back treatment may be applied, or a release paper or a release film may be bonded.

  The thickness of the pressure-sensitive adhesive layer may be about 5 to 100 μm. More preferably, it is about 10-30 micrometers.

  Hereinafter, the moisture-proof cardboard box of the present invention will be described with specific examples.

  As a plastic film substrate, a biaxially stretched polyethylene terephthalate (PET) film having a thickness of 12 μm was used, and a transparent deposited thin film layer made of aluminum oxide having a thickness of 15 nm was laminated by a vacuum deposition apparatus using an electron beam heating method. During vapor deposition, oxygen gas was introduced.

Next, A liquid, B liquid, C liquid, D liquid, E liquid, and F liquid were prepared as follows.
<Liquid A>
A hydrolyzed solution obtained by adding 70 g of hydrochloric acid (0.1N) to 20 g of tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ) and 10 g of methanol, followed by hydrolysis for 30 minutes.
<Liquid B>
5% of polyvinyl alcohol, water / methanol = 95/5 aqueous solution.
<C liquid>
A hydrolysis solution prepared from 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate in a water / IPA = 1/1 solution.
<D liquid>
Hydrochloric acid (1N) is gradually added to β- (3,4 epoxycyclohexyl) trimethoxysilane and isopropyl alcohol (IPA solution), stirred for 30 minutes, hydrolyzed, and then added with water / IPA = 1/1 solution. Hydrolysis solution prepared by decomposing.
<E liquid>
Hydrolysis prepared by gradually adding hydrochloric acid (1N) to γ-glycidoxypropyltrimethoxysilane and IPA solution, stirring for 30 minutes, hydrolyzing and then hydrolyzing with water / IPA = 1/1 solution solution.
<F liquid>
Hydrolysis solution prepared by gradually adding hydrochloric acid (1N) to vinyltrimethoxysilane and IPA solution, stirring for 30 minutes to cause hydrolysis, followed by hydrolysis with water / IPA = 1/1 solution.

Subsequently, coating liquids a, b, c, and d for forming a gas barrier film layer were prepared as follows.
<Coating fluid a>
Liquid A, liquid B, and liquid C were mixed at a ratio of A / B / C = 70/20/10 (wt%) to obtain a gas barrier coating liquid a.
<Coating solution b>
Liquid A, liquid B and liquid D were mixed at a ratio of A / B / D = 70/20/10 (% by weight) to obtain a gas barrier coating liquid b.
<Coating liquid c>
Liquid A, liquid B, and liquid E were mixed at a ratio of A / B / E = 70/20/10 (% by weight) to obtain a gas barrier coating liquid c.
<Coating solution d>
Liquid A, liquid B and liquid F were mixed at a ratio of A / B / F = 70/20/10 (wt%) to obtain a gas barrier coating liquid d.

  Then, the thin films of the above coating liquids a, b, c, and d are provided on the vapor deposition thin film layer of the transparent vapor deposition thin film laminate obtained in the above process by a gravure coating method, and then dried at 120 ° C. for 2 minutes. Then, a gas barrier coating layer having a thickness of 0.5 μm was formed, and vapor-deposited plastic films a to d were obtained.

  Moreover, the vapor deposition plastic film e was obtained like the manufacturing method of the vapor deposition plastic film a except not having introduce | transduced oxygen gas in the case of vapor deposition and performing aluminum vapor deposition.

  Further, a vapor-deposited plastic film f was obtained in the same manner as the method for producing the vapor-deposited plastic film a except that the vapor-deposited thin film layer was made of silicon oxide.

  Furthermore, a vapor-deposited plastic film g was obtained in the same manner as the method for producing the vapor-deposited plastic film a except that the gas barrier coating layer was not provided.

  Each of the vapor-deposited plastic films a to g and the plastic film (linear low-density polyethylene film having a thickness of 60 μm) h and the corrugated board obtained as described above are bonded together via a polyurethane resin solvent-based adhesive. Thus, corrugated board laminates a to h were obtained. Subsequently, using these corrugated cardboard laminates a to h, the vapor-deposited plastic films a to g, or the plastic film h side is placed on the inner surface, and the moisture-proof cardboard boxes a to f according to the present invention are used. Corrugated cardboard boxes g and h for comparison were obtained. At this time, A flute double-sided cardboard was used as the cardboard.

In addition, in order to compare the degree of moisture resistance, the water vapor transmission rate of corrugated cardboard in which a vapor-deposited plastic film or a plastic film was not bonded was also measured, but measurement was impossible.
<Evaluation 1>
The water vapor permeability (g / m ² · day) was measured on the corrugated board laminates a to h constituting a part of the corrugated board boxes a to h obtained as described above, and the moisture resistance was evaluated. . The measurement results are shown in Table 1.

本発明に係る防湿段ボール箱は、優れた防湿性を備えていることが分かった。

It has been found that the moisture-proof cardboard box according to the present invention has an excellent moisture-proof property.

It is explanatory drawing which shows the schematic cross-sectional structure of a corrugated-cardboard laminated body. It is explanatory drawing which shows the general | schematic cross-section structure of another corrugated-cardboard laminated body. It is explanatory drawing which shows the general | schematic cross-section structure of another cardboard laminated body. It is a fragmentary sectional view of the laminated body which comprises the moisture-proof cardboard of this invention. It is explanatory drawing which shows a mode when the moisture-proof cardboard box of the present invention is sealed with a sealing seal.

Explanation of symbols

11, 21, 31 Plastic film substrate 12, 22, 32 Vapor deposited thin film layers 13, 23, 33 made of metal or metal oxide Gas barrier coating layers 14, 24, 34 Vapor deposited plastic films 15, 25, 35 Corrugated cardboard 26, 36 Plastic film 40 Cardboard box 41 Sealing tape

Claims (4)

Silicon represented by vapor-deposited thin film layer of metal or metal oxide, and Si (OR ¹ ) ₄ and R ² Si (OR ³ ) ₃ (OR ¹ and OR ³ are hydrolyzable groups, and R ² is an organic functional group) Corrugated cardboard in which a vapor-deposited plastic film having at least a gas barrier coating film, which is a heat-dried thin film made of a solution in which a compound or a hydrolyzate thereof is mixed with a water-soluble polymer having a hydroxyl group, is laminated on at least one side of the cardboard A moisture-proof corrugated cardboard box, characterized in that the laminate is used and boxed such that the vapor-deposited plastic film laminate side is located on the inner surface.   The moisture-proof corrugated cardboard box according to claim 1, wherein the vapor-deposited plastic film has a metal or metal oxide vapor-deposited thin film layer having a thickness of 5 to 100 nm.   3. The moisture-proof cardboard box according to claim 1, wherein a plastic film is further laminated on the vapor-deposited plastic film.   The moisture-proof cardboard box according to any one of claims 1 to 3, wherein the moisture-proof cardboard box is sealed with a sealing tape having at least a metal or metal oxide vapor-deposited thin film layer.

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