JP2003193399A - Moistureproof and rustproof paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide moistureproof and rustproof paper that has rust preventiveness and water defiberization properties enough to be recycled as used paper and can protect the content in the package from moisture, even when the package is placed under high humidity conditions or wetted with water. <P>SOLUTION: This moistureproof paper has a moistureproof layer including a synthetic resin and tabular pigments on at least one face of the paper substrate and the moistureproof paper includes a volatile rust-preventive agent. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to moisture resistance, water resistance,
The present invention relates to a moisture-proof and rust-proof paper that has rust-proof properties and water disintegration properties that can be recycled as waste paper.

[0002]

2. Description of the Related Art Generally, the vaporized vapor is applied to a support with a vaporizable anticorrosive agent that exhibits an anticorrosive effect on various metals.
Impregnated rustproof packaging materials, especially rustproof paper whose support is paper such as kraft paper, are well known and are widely used as packaging materials for storage and transportation of metals as industrial paper. However, since rust-preventive paper has water permeability and hygroscopicity as the support paper, when the metal package made of rust-proof paper is kept under high temperature and high humidity, or when the package gets wet with water. Has a drawback that the metal, which is the content, is exposed to moisture, so that it easily rusts. Further, the vaporized rust preventive agent is partly scattered to the outside of the package made of rust preventive paper, so that the rust preventive agent is wasted and the rust preventive effect does not last long.

On the other hand, the laminated rust-proof paper obtained by applying or impregnating a rust-preventive agent on the paper surface of a laminated paper obtained by laminating a polyolefin film such as polyethylene or polypropylene on kraft paper is difficult for the film layer to permeate moisture. Therefore, even if the metal package with laminated rustproof paper is kept under high temperature and high humidity, or if the package is wet with water,
Since the metals that are the contents are protected from moisture, it exhibits an excellent rust prevention effect. Further, the gas barrier property of the film layer prevents the vaporized rust preventive agent from scattering to the outside of the package, the rust preventive agent works effectively without being wasted, and the rust preventive effect lasts for a long time.

However, since the laminated anticorrosive paper has a film layer, it cannot be re-disintegrated in water and cannot be recovered after use and reused as waste paper. Further, even if it is discarded, there is a concern that it may cause environmental pollution because the method is only by incineration or landfill.

Therefore, as a technique that can be recycled as waste paper and has a moisture-proof property, a water-based coating layer containing a resin as a main component is provided on the surface of a paper support, and a vaporizable rust preventive composition layer is provided on the back surface thereof. A technology that enables the recycling of used paper by providing a sheet (Japanese Patent Laid-Open No. 17886/1993), a paper layer having a rust preventive agent attached to a paper material, and a moisture barrier layer composed of a water disintegrating moisture barrier are used for recycling. Rust-proof paper that can be reused as paper (Patent Document 200
0-170095) is proposed. But,
In these methods, the rust-preventing effect and the disintegration property when recycled as waste paper are sufficient, but the moisture vapor permeability which is an index of the moisture-proof property is still insufficient. In addition, a recyclable moisture-proof and rust-proof buffer paper in which moisture-proof paper, water-resistant paper, and rust-proof paper are laminated with a water disintegrating adhesive (Japanese Patent Laid-Open No. 2001-145).
No. 7) has been proposed, but there is a problem that the number of manufacturing steps is complicated and the like.

[0006]

DISCLOSURE OF THE INVENTION An object of the present invention is to have anticorrosive properties and water disintegration properties that can be recycled as waste paper.
Moreover, the moisture content of the package can be protected from moisture even if the package is exposed to high humidity or water,
The present invention provides a moisture-proof and rust-proof paper having water resistance.

[0007]

The present invention adopts the following method in order to solve the above problems. That is, the first aspect of the present invention is
In a moisture-proof paper having a moisture-proof layer containing a synthetic resin and a tabular pigment on at least one surface of a paper support, the moisture-proof paper is a moisture-proof and rust-proof paper containing a vaporizable rust inhibitor.

The second aspect of the present invention is the moisture-proof rust-preventive paper according to the first aspect of the present invention, wherein the tabular pigment is at least one selected from phyllosilicate minerals and highly swelling clay minerals.

The third aspect of the present invention is the first aspect of the present invention, which has a moisture-proof layer on one side of the paper support and a rust preventive coating layer on the other side.
It is the moisture-proof and rust-proof paper according to 2 above.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. In the moisture-proof and rust-preventive paper of the present invention, in order to impart moisture-proof property to the paper support, a pigment which seems to be impermeable to water vapor, for example, a tabular pigment such as muscovite is used as a polymer such as a synthetic resin latex. The mixture is mixed with to form a moisture-proof layer. The moisture-proof mechanism is that the water vapor permeation area is small in the plane, and in the thickness direction, the tabular pigments are arranged in parallel to the surface of the moisture-proof layer and laminated, so that the water vapor in the moisture-proof layer is flat. Since the pigment permeates while bypassing it (curved path effect), the water vapor permeation distance becomes long, and as a result, the moisture resistance is significantly improved. Further, the moisture-proof layer is separated by mechanical action such as pulper. It is speculated that this is because the tabular pigment serves as a base point and the moisture-proof layer is mechanically destroyed from there. In order to impart rustproofness to such a moistureproof paper, a vaporizable rustproofing agent is applied and impregnated to obtain a target recyclable moistureproof rustproof paper.

The resin that can be used to form the moisture-proof layer of the present invention is not particularly limited as long as it is a resin that forms a continuous film without pinholes and has moisture-proof properties. A measure of the moisture resistance of the resin used is 40 ° C 90% R of a single resin coating (20 μm thick).
Water vapor transmission rate in H is less than 1000 g / m ² · 24 hr,
It is preferably less than 500 g / m ² · 24 hr, more preferably less than 200 g / m ² · 24 hr. Specific examples of the resin include styrene / butadiene-based copolymer synthetic resin,
Methacrylate / butadiene copolymer synthetic resin, acrylic / styrene copolymer synthetic resin, acrylic ester synthetic resin, polyester synthetic resin, acrylonitrile synthetic resin, ethylene / vinyl alcohol synthetic resin, vinyl acetate synthetic resin, Ethylene / vinyl acetate copolymer synthetic resin, vinyl chloride resin, vinylidene chloride resin, urethane resin, polyamide resin, olefin resin, olefin / unsaturated carboxylic acid copolymer resin, styrene resin, etc. .

Of these, vinyl polymers such as styrene / butadiene copolymer synthetic resins, acrylic / styrene copolymer synthetic resins, and olefin / unsaturated carboxylic acid copolymer resins are preferable in terms of moisture resistance. is there. Further, a biodegradable resin or a resin derived from a natural product alone forms a continuous film, and thus has the above-mentioned moisture resistance (1000 g / m ² · 24 h).
r) or less) can be used as the moisture-proof layer forming resin of the present invention.

The above-mentioned resin has good pigment miscibility and is easy to handle because of its viscosity as a coating material. Furthermore, the film-forming property of the coating film can be controlled by the drying conditions after coating, and the moisture-proof property. It is preferable to use it in the form of an emulsion polymer or an alkaline solution that makes it possible to control the balance between the dispersibility and disintegration property. The vinyl-based emulsion polymer used in the present invention is obtained by emulsion-polymerizing a vinyl-based monomer, and generally has a high molecular weight such as a molecular weight of several hundred thousand to several million. . The vinyl emulsion polymer is preferably dispersed in an aqueous medium and in a latex (emulsion) state, that is, it is obtained by emulsion polymerization. The vinyl-based monomer used to obtain the vinyl-based emulsion polymer includes aromatic vinyl monomers, aliphatic conjugated diene-based monomers, unsaturated carboxylic acid monomers and other copolymerizable monomers. Examples include a polymer. Synthetic rubber latex such as styrene / butadiene latex, methyl methacrylate / butadiene latex, and styrene / acrylic emulsion, acrylic ester polymer emulsion, polystyrene emulsion, etc. obtained by polymerizing them are vinyl emulsion polymers. Can be mentioned.

The aromatic vinyl monomer is capable of imparting appropriate hardness and water resistance to the obtained vinyl emulsion polymer, and is selected from, for example, styrene, α-methylstyrene, monochlorostyrene, vinyltoluene and the like. You can
Styrene is especially preferable, and 30% by mass of styrene is used.
The vinyl-based emulsion polymer containing as a constituent monomer above,
It is particularly preferable because the effect aimed at by the present invention can be efficiently exhibited. The aliphatic conjugated diene monomer is
It imparts appropriate flexibility to the obtained vinyl-based emulsion polymer, for example, 1,3-butadiene, 2-methyl-
1,3-Butadiene, 2-chloro-1,3-butadiene and the like can be mentioned, with 1,3-butadiene being particularly preferred.

The unsaturated carboxylic acid monomer is effective for enhancing the adhesive force of the obtained vinyl emulsion polymer and improving the stability of the vinyl emulsion polymer latex as a colloid. Acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, itaconic acid, fumaric acid, maleic acid, unsaturated carboxylic acids such as butenetricarboxylic acid, itaconic acid monoethyl ester,
Unsaturated polycarboxylic acid alkyl ester having at least one carboxyl group, such as fumaric acid monobutyl ester and maleic acid monobutyl ester, and further as another acidic monomer for the same purpose,
Examples thereof include unsaturated sulfonic acids such as acrylamide propane sulfonic acid, acrylic acid sulfoethyl sodium salt, and methacrylic acid sulfopropyl sodium salt, or salts thereof. Among these, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, etc. It is preferably used in the present invention.

As other copolymerizable monomers, unsaturated carboxylic acid alkyl esters such as methyl acrylate, methyl methacrylate, ethyl acrylate and butyl acrylate, unsaturated nitriles such as acrylonitrile and methacrylonitrile, Β-hydroxyethyl acrylate,
Unsaturated carboxylic acid hydroxyalkyl esters such as β-hydroxypropyl acrylate and β-hydroxyethyl methacrylate, unsaturated carboxylic acid amides and derivatives thereof such as acrylamide, methacrylamide, N-methylol acrylamide and diacetone acrylamide, acrylic acid Examples thereof include unsaturated carboxylic acid glycidyl esters such as glycidyl and glycidyl methacrylate, and vinyl compounds such as acrolein and allyl alcohol. Among these monomers, methyl methacrylate as an unsaturated carboxylic acid alkyl ester, acrylonitrile as an unsaturated nitrile, β-hydroxyethyl acrylate as an unsaturated carboxylic acid hydroxyalkyl ester, and unsaturated carboxylic acid amide and acrylamide as a derivative thereof. Is preferably used.

As the olefin constituting the olefin / unsaturated carboxylic acid copolymer resin which can be used in the present invention, α-olefins such as ethylene and propylene are preferable, and ethylene is particularly preferable. As the unsaturated carboxylic acid, acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid and the like are preferable, and acrylic acid and methacrylic acid are particularly preferable.

The ethylene-acrylic acid or methacrylic acid (hereinafter, both of them are collectively referred to as (meth) acrylic acid) copolymer, and more preferably the ethylene- (meth) acrylic acid copolymer has a weight average molecular weight of 5,000 to 100,000. , Particularly preferably 10,000 to 50,000. When the weight average molecular weight is less than 5,000, the low molecular weight component increases, so the moisture-proof surface slips, or the moisture-proof surface and the back surface of the moisture-proof paper, or the moisture-proof surface and the contents packed in the package are blocked (melting due to heat, pressure, or the passage of time). It is not preferable because it is easy to wear or stick). When the mass average molecular weight exceeds 100,000, the production becomes difficult, and the effect on the moisture resistance, blocking resistance or slip resistance reaches a ceiling.

The olefin / unsaturated carboxylic acid copolymer resin used in the present invention is preferably dispersed in an aqueous medium (latex type) from the viewpoint of film forming property. Examples of commercially available products that can be used as the latex-type olefin / unsaturated carboxylic acid copolymers described above include Hitec S-3121, 7024, 3125, and 3123.
And 3127 (all manufactured by Toho Chemical Industry Co., Ltd.) and the like.

Further, an olefin / unsaturated carboxylic acid copolymer resin obtained by solubilizing an olefin / unsaturated carboxylic acid copolymer resin with an alkali (alkali-soluble type) is also preferable in terms of film-forming property. Examples of the type of alkali include sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia, amines such as alkanolamines, etc. However, if the amount of alkali metal ions in the moisture-proof layer is large, the moisture-proof property is adversely affected ( Ammonia and amines are preferable in view of moisture resistance. In particular, ammonia, low boiling points (boiling point 150 ° C or lower), or amines that azeotrope with water evaporate from the moisture-proof film during drying.
It is preferable because it improves the water resistance of the olefin / unsaturated carboxylic acid copolymer and improves the moisture resistance. Examples of commercially available products that can be used as the alkali-soluble olefin / unsaturated carboxylic acid copolymers include Zyxen-AC, Zyxen-N, and Zyxen-L (all manufactured by Sumitomo Seika Co., Ltd.).
And so on.

The inventors of the present invention disclose in Japanese Patent Application Laid-Open No. 11-50388 that the moisture resistance, particularly under ultrahigh humidity conditions, is adversely affected by the amount of the alkali metal ion component contained in the moisture protection layer. is doing. The influence of alkali metal ions on the moisture resistance is considered as follows.
The moisture permeability coefficient of a certain film-like thin film (here, the moisture-proof layer formed on the support) is represented by the product of the solubility coefficient and the diffusion coefficient. In this case, it is assumed that the thin film has no pinhole with a diameter larger than that of water molecules. Strictly speaking, dissolution and diffusion can be analyzed mathematically only when Fick's law is satisfied and the dissolution follows Henry's law. The permeation process (dissolution and diffusion) of water molecules into polymer membranes often does not follow Fick's law or Henry's law, but analyzing the permeation process separately for dissolution and diffusion reveals the permeation mechanism. Important above. The solubility coefficient is the solubility of water vapor in a coating film at a certain water vapor pressure. In other words, it means the water content of the coating film at a certain vapor pressure, and the solubility of water molecules is proportional to the partial pressure of water vapor when the dissolution follows Henry's law. The solubility coefficient is S = C / p
(S: solubility coefficient, C: water molecule concentration, p: water vapor partial pressure)
, The water vapor partial pressure contained in 1 g of the polymer film is 1 c
It is often expressed as the amount of water at mHg. It can be said that the larger the solubility coefficient, the more likely it is that water will be contained. The diffusion coefficient indicates the degree to which water molecules dissolved in the coating film move and diffuse in the thin film. The larger the diffusion coefficient, the easier the water molecules in the coating film move and diffuse. When the permeation satisfies Fick's law, the flow velocity J (the amount of the substance passing through a unit area perpendicular to the flow direction in a unit time) is the concentration gradient d of the permeating substance.
Proportional to C / dx. Here, C is the concentration and x is the position in the film thickness direction. The proportional coefficient D at this time is the diffusion coefficient (J
= D · dC / dx). The permeability coefficient is the product of this solubility coefficient and the diffusion coefficient. In order to reduce the permeation coefficient, that is, to improve the moisture resistance, it can be achieved by reducing the solubility coefficient or the diffusion coefficient. The reduction of the solubility coefficient can be achieved by 1) increasing the orientation of the polymer film or increasing the crystallinity, and 2) reducing the hydrophilic functional groups and hydrophilic components.
Further, the diffusion coefficient is 1) to increase the orientation of the polymer film and to increase the crystallinity, 2) to increase the rigidity of the polymer chain and to increase the glass transition temperature, and 3) to increase the cohesive energy density of the polymer. It can be made smaller by such methods. Thus, the permeation coefficient can be expressed by the product of the dissolution coefficient and the diffusion coefficient (the permeation dissolution-diffusion theory). The permeability coefficient can be obtained from the moisture permeability and the film thickness. The solubility coefficient is obtained from the water content and the water vapor pressure. The diffusion coefficient can be obtained from the delay time of the gas permeation curve (time-permeation amount curve) and the slope of the initial linear portion of the moisture absorption or dehumidification curve. If two coefficients are obtained, the remaining one coefficient can be obtained from the equation P = DS.

If a hydrophilic component (alkali metal ion or water-soluble compound) is present in the moisture-proof layer, the solubility coefficient becomes high and the moisture-proof property becomes poor. Moreover, when the adsorption amount of the polymer film increases due to the higher solubility coefficient, the polymer film is plasticized by water and the polymer chains easily move (glass transition temperature decreases), and the adsorbed water molecules become In many cases, diffusion becomes easy and the diffusion coefficient becomes large. Therefore, if the hydrophilic component increases in the moisture-proof layer, not only the solubility coefficient but also the diffusion coefficient increases, and the moisture-proof property becomes synergistically deteriorated. This phenomenon is particularly noticeable when the humidity is high, and specifically, when the relative humidity is 90% or more, the adverse effect of the hydrophilic component on the moisture resistance is increased.

Lithium ion is used as the alkali metal ion.
(Li⁺), Sodium ion (Na ⁺), Potassium
On (K⁺), Rubidium ion (Rb⁺),cesium
Ion (Cs⁺), Francium ion (Fr⁺) Is
Among them, lithium ion (Li⁺),sodium
Ion (Na⁺), Potassium ion (K⁺) Is common
Yes, especially sodium ion (Na⁺) Is a lot. Arca
Li-metal ions are hydroxylated by alkali metal ions in the moisture-proof layer.
Compounds, carbonate compounds, halogen compounds, sulfates, phosphates,
Or has sulfuric acid, carboxylic acid, phosphoric acid, nitric acid group
It is considered to exist in the form of a neutralized salt with the compound. This
Alkali metal ion-derived compounds such as
Which is a hygroscopic compound. Hygroscopicity is alkali metal io
It greatly changes depending on the type of counter ion or counter ion. For example charcoal
Potassium acid starts to absorb moisture rapidly when the humidity is about 30%.
It Sodium chloride starts to absorb moisture when the humidity is around 60%.
Start. Humidity of sodium benzoate exceeds 90%
Absorbs moisture. Therefore, the humidity is higher than the relative humidity
After that, it adversely affects the moisture resistance. 90% humidity
Above that, the moisture absorption tends to increase exponentially.
In some cases, the weight is more than 5 times the weight of the alkali metal compound.
Some absorb moisture. Alkali metal ion is
It is necessary when used as an aqueous solution or as an aqueous solution, but many
In the case of, it is possible to substitute ammonia or ammonium ion
is there. Ammonia is generated by the heat used to form the anchor layer.
Evaporate with water vapor and almost remain in the anchor layer
Since it does not exist, it does not affect the moisture resistance. Therefore Arca
Ammonia or ammonium iodide instead of metal ions
It is preferable to use

The first preferred tabular pigment that can be preferably used in the moisture-proof layer of the present invention is a phyllosilicate mineral. Those belonging to the phyllosilicate minerals are plate-like or flaky and have clear cleavage properties, and are mica, pyrophyllite, talc (chlorite), chlorite, septe chlorite, serpentine, stilpnomelene, clay There are minerals. Among these, minerals that produce large particles when produced and have a large amount of production, for example, mica and talc are preferable. Mica includes muscovite (mascobite), sericite (sericite), phlogopite, biotite, fluorophlogopite (artificial mica, synthetic mica), soda mica, vanadine mica. , Illite, chimica, paragonite, brittle mica, potassium tetrasilicon mica, sodium tetrasilicon mica,
Examples thereof include sodium teniolite and lithium teniolite. Synthetic products such as synthetic mica that is compositionally similar to talc are also included in the scope of the present invention. Clay minerals such as kaolin are also generally called tabular crystals. However, if one crystal is taken, there is a flat plate-like portion but it is granular as a whole. However, among kaolins, deramikarin, which is formed into a flat plate by intentionally peeling off the crystal layer, can be used as the flat pigment in the present invention. Further, it is preferable to use a tabular pigment having a particle diameter corresponding to the film thickness of the moisture-proof layer. In that case, the tabular pigment is pulverized and classified by a pulverizer such as a ball mill, a sand grinder, a cobol mill or a jet mill to obtain a desired particle size, and then used in the present invention.

The second tabular pigment preferably used in the present invention includes highly swelling clay minerals of the smectite group and the vermiculite group. More specific examples include dickite, nacrite, smectite, halloysite, antigorite, chrysotile, pyrophyllite, tetrasilylic mica, sodium teniolite, margarite, vermiculite, xanthophyllite, chlorite and the like. . Smectite is particularly preferable, and examples of the smectite include montmorillonite, hydelite, nontronite, saponite, iron saponite, hectorite, sauconite, stevensite and the like. The formula for synthetic smectite is
(Na and / or Li) _0.1 to _1.0 Mg _{2 . 4} ~
_2.9 Li _0.0 to _0.6 Si _3.5 to _4.0 O _9.0
˜10.6 (OH and / or F) _1.5 to _2.5 , and synthetic mica includes swellable fluorine mica. JP-A-5-270815 and JP-A-7-187
It is synthesized by the method described in Japanese Patent No. 657. As commercial products of clay minerals, natural bentonite generally called sodium bentonite, and commercially available products Kunipia, Smecton (manufactured by Kunimine Industry), Veegum (manufactured by Vanderbilt), Laponite (manufactured by Laporte), DM Clean A, D
MA-350, Na-Ts (manufactured by Topy Industries, Ltd.), Wenger
(Manufactured by Toyojun Yoko) and the like, and these may be used alone or in combination of two or more kinds.

In the present invention, the highly swelling clay mineral means a swelling force (standard test method JB of Japan Bentonite Industry Association).
Measured by the method according to AS-104-77) is 20 ml /
It refers to 2 g or more of clay minerals. Specific examples of these include the above Kunipia (swelling power: 65 ml / 2
g or more), smecton (swelling power: 60 ml / 2 g or more),
DM Clean A, DMA-350, Na-Ts (swelling power: 20 ml / 2 g or more), ME-100 (trademark: manufactured by Corp Chemical Co., swelling power 20 ml / 2 g or more) and Bengel (swelling power 38 ml / 2 g or more). and so on.

The swelling power of the highly swelling clay mineral is closely related to its ion exchange equivalent, and if the ion exchange equivalent is small, the swelling power will also be small, which is not preferable for use in the present invention. The ion exchange equivalent of the swelling clay mineral preferable for use in the present invention is 10 meq or more per 100 g, more preferably 50 to 300 meq, particularly preferably 6 meq.
The thing of 0-300 milliequivalent or more is mentioned. If the ion exchange equivalent is more than 300 milliequivalents, gelation tends to occur when the solution is made into an aqueous solution, and handling becomes difficult, which is not suitable. The ion exchange equivalent here is determined by the amount of methylene blue adsorbed. In general,
85-130 for 100g of natural and synthetic smetite
It has a milliequivalent ion exchange equivalent and is therefore particularly preferred for the present invention. Further, as the swelling clay mineral, those having an aspect ratio (Z) of 50 to 5000 are preferable, and the aspect ratio (Z) is shown by a relationship of Z = L / a [L is a moisture-proof layer] It is the length of the clay mineral dispersed in layers inside, and a is the unit thickness, which is determined by electron microscopy.]. Further, the swelling clay mineral (swelling power 20 ml / 2 g or more) and a non-swelling clay mineral such as mica (swelling power less than 20 ml / 2 g) may be mixed and used. The mixing ratio is not particularly limited, but swelling clay mineral / non-swelling clay mineral 1
The range of / 99 to 99/1 (solid content) is preferable. When the proportion of swelling clay minerals increases, the disintegration property improves, but the moisture resistance tends to decrease slightly. Conversely, when the proportion of non-swelling clay minerals increases, the moisture resistance improves but the disintegration property decreases slightly. Tend to do.

Other tabular pigments used in the present invention are so-called inorganic layered compounds having a stacked structure and high tabularity bonded by ions. Specific examples of the inorganic layered compound include graphite, a phosphate derivative compound (zirconium phosphate compound), and a chalcogen compound [a dichalcogen compound represented by the formula MX _2] . Here, M is a group IV (Ti, Zr, Hf), V
X represents a group (V, Nb, Ta) or VI (Mo, W) element, and X represents a chalcogen (S, Se, Te). ] Is mentioned.

The tabular pigment used in the present invention is
Those having an average particle size of 20 nm to 100 μm in a state of being dispersed in water or a solvent are suitable, preferably 0.1 μm to 50 μm, more preferably 1 μm.
˜30 μm. When the average particle diameter is less than 20 nm, the aspect ratio becomes small and the effect of improving moisture resistance is small. On the other hand, when it exceeds 100 μm, the pigment is projected from the surface of the coating layer, resulting in poor appearance and reduced moisture resistance, which is not preferable. The average particle size of the tabular pigment used in the present invention dispersed in water or a solvent is a value measured by a particle size distribution measuring device by laser diffraction applying the light scattering theory when the average particle size is 0.1 μm or more. . Further, for those having an average particle size of 0.1 μm dispersed in water or a solvent,
It is a value measured using the dynamic light scattering method.

The aspect ratio of the tabular pigment used in the present invention is preferably 5 or more, and particularly preferably 10.
That is all. If the aspect ratio is less than 5, the moisture resistance is lowered because the curved path effect is small. The larger the aspect ratio, the greater the number of layers of the tabular pigment in the coating layer, and therefore the higher moistureproof performance is exhibited. The thickness of the tabular pigment is measured from the photograph of the cross section of the moisture-proof film. The thickness of 0.1 μm or more is determined by image analysis from an electron micrograph. Those having a thickness of less than 0.1 μm are obtained by image analysis from transmission electron micrographs. The aspect ratio as referred to in the present invention is the average particle diameter dispersed in the above water or solvent divided by the thickness obtained from the cross-sectional photograph of the moisture-proof film. The compounding amount of the synthetic resin and the tabular pigment in the moisture-proof layer is 99/1 in terms of mass.
~ 30/70 is preferable, and more preferably 90/10
35/65, particularly preferably 85/15 to 40/60. When the amount of the tabular pigment blended is less than 1%, the moisture-proof property improving effect and the disintegrating property improving effect become small. When the tabular pigment becomes larger than 70%, the resin filling the gaps between the tabular pigments becomes insufficient, resulting in an increase in voids and pinholes and deterioration in moisture resistance.

In the present invention, it is preferable to add a moisture-proof property improver in order to improve the moisture-proof property of the moisture-proof layer. The moisture resistance improver reacts with a functional group contained in the synthetic resin to make it hydrophobic, or crosslinks to make it hydrophobic, or a tabular pigment is coated to make it hydrophobic. Those which make the tabular pigments hydrophobic and promote the laminated orientation parallel to each other, or those which enhance the adhesiveness with the synthetic resin and / or the tabular pigment, or those which fill these gaps, etc. The moisture-proof layer improves the moisture-proof property.

The moisture-proof property improver used in the present invention includes a urea-formaldehyde condensation reaction product, a melamine-formaldehyde condensation reaction product, and a carbon atom number of 1 to 1.
Eight aldehyde compounds, epoxy compounds having one or more epoxy groups, cross-linking polyvalent metal compounds, organoalkoxysilane compounds, organoalkoxy metal compounds, organic amine compounds, polyamide compounds, polyamide polyurea compounds, polyamine polyureas Compound, polyamidoamine polyurea compound, polyamidoamine compound,
Polyamide amine-epihalohydrin or formaldehyde condensation reaction product, polyamide polyurea-epihalohydrin or formaldehyde condensation reaction product, polyamine polyurea-epihalohydrin or formaldehyde condensation reaction product, and polyamidoamine polyurea-epihalohydrin or formaldehyde condensation reaction product It is preferable to include at least one selected from the above.

Among the compounds used for the moisture-proof property improver, the urea-formaldehyde condensation reaction product and the melamine-formaldehyde condensation reaction product have a methylol group derived from formaldehyde, which is an α-olefin / unsaturated carboxylic acid. Reacts with acid copolymers, especially hydrogen bonds or dehydration reactions with their carboxylic acid groups to cross-link the polymer or copolymer molecules, making them hydrophobic and water insoluble (three-dimensional network structure) be able to. Further, the condensation product stably binds the α-olefin / unsaturated carboxylic acid copolymer and the tabular pigment without chemically reacting with the α-olefin / unsaturated carboxylic acid copolymer. do it,
The moisture-proof performance of the moisture-proof layer can be enhanced.

The aldehyde compound having 1 to 8 carbon atoms used in the moisture-proof property improver is formaldehyde,
It includes acetaldehyde, glyoxal, propyl aldehyde, propanedial, hexanedial and the like, which is added to the hydrophilic functional group of the polymer or copolymer contained in the synthetic resin component (a) at its aldehyde group. By reacting, it can be rendered hydrophobic and water-insoluble.

The epoxy compound having one or more epoxy groups used in the moisture-proofing agent includes, for example, a polyglycidyl ether compound and a polyamide-epoxy resin, which is an α-olefin / unsaturated carvone. It can be made hydrophobic and water-insoluble by a ring-opening addition reaction with a carboxylic acid contained in the acid copolymer.
In addition, the above-mentioned epoxy compound, when the moisture-proof layer is heated and dried, α
-The olefin / unsaturated carboxylic acid copolymer and the tabular pigment can be firmly bound and the gaps between them can be filled to improve the moisture-proof effect of the moisture-proof layer.

In the present invention, the cross-linking reactive polyvalent metal compound used as the moisture resistance improver includes, for example, ammonium zirconium carbonate, zirconium alkoxide, titanium alkoxide and aluminum alkoxide, and the polyvalent metal compounds in these compounds are included. The metal is coordinate-bonded or covalently bonded with the carboxylic acid in the α-olefin / unsaturated carboxylic acid copolymer to make the α-olefin / unsaturated carboxylic acid copolymer hydrophobic and water-insoluble. be able to.

In the present invention, the organoalkoxysilane compound and the organoalkoxy metal compound used as the moisture resistance improver are generally called as a coupling agent, and in the inorganic-organic composite material system, they are inorganic. The component and the organic component are chemically cross-linked, or at least one of them is chemically or physically bound to enhance the affinity of the two, and thereby the inorganic-
It is intended to improve the heat resistance, water resistance and mechanical strength of the organic composite material. In the present invention, the organoalkoxysilane compound and the organoalkoxy metal compound improve the affinity and adhesion of the α-olefin / unsaturated carboxylic acid copolymer and the tabular pigment to bring them into close contact with each other to form a gap. Can be prevented, and thereby the moisture-proof performance of the moisture-proof layer can be improved.

The organoalkoxysilane compound used in the present invention contains a Si atom in its hydrophilic portion, and is, for example, vinyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxy. Propyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, and N-β- (aminoethyl)-
γ-aminopropyltrimethoxysilane and the like are included.

The organoalkoxy metal compound used in the present invention contains a polyvalent metal atom (eg, Ti, Al, etc.) in its hydrophilic portion, and is, for example, isopropyltriisostearoyl titanate or isopropyltrioctano. Includes titanate compounds such as iltitanol, isopropylisostearoyl diacrylic titanate, isopropyltricumylphenyl titanate, and isopropyltri (N-amidoethylaminoethyl) titanate, and aluminum compounds such as acetoalkoxyaluminum diisopropylate.

Organoalkoxysilane compounds and organoalkoxy metal compounds (hereinafter referred to as coupling agents) have a molecular structure of Si, Ti, or Al.
It has a hydrophilic portion containing atoms and having a high reactivity or affinity with an inorganic substance, and a hydrophobic portion having a high reactivity or affinity with an organic compound. This hydrophilic portion is formed by hydrolyzing an alkoxy group bonded to Ti, Al, or Si atom.

The reaction between the hydrophilic group of the coupling agent and the inorganic compound is said to proceed in the following order. That is, (1) formation of a hydrophilic group formed by hydrolysis of the alkoxy group of the coupling agent, (2) oligomerization by dehydration condensation of the hydrophilic group of the coupling agent, (3) hydrophilic group on the inorganic surface or adsorbed water Between the hydrophilic group of the coupling agent and the hydrophilic group of the coupling agent, and (4) formation of a covalent bond between the hydrophilic group of the coupling agent and the hydrophilic group of the inorganic surface by the heat dehydration reaction. A methoxy group as the hydrolyzable alkoxy group,
An ethoxy group, an isopropoxy group, an octyloxy group and the like are used. Further, the reactivity of the hydrophilic group and the inorganic compound of the coupling agent is high when the inorganic compound has a hydroxyl group on the surface such as glass, silica, alumina, talc, clay and mica, but in the case of the titanate coupling agent, Even if the inorganic compound is calcium carbonate, barium sulfate, or calcium sulfate, high reactivity is exhibited.

On the other hand, regarding the hydrophobic group portion of the coupling agent, when the hydrophobic group portion is an organic oligomer, a polymer organic film is formed on the surface of the inorganic compound to completely hydrophobize the surface to form a synthetic resin matrix. Increase the adhesiveness of. Further, when the hydrophobic group portion has a reactive organic functional group such as an epoxy group, a vinyl group or an amino group, the functional group and α
-Olefin / unsaturated carboxylic acid copolymer is crosslinked,
Adhesion to α-olefin / unsaturated carboxylic acid copolymer is enhanced. Therefore, the composition of the hydrophobic group portion of the coupling agent can be selected according to the composition of the α-olefin / unsaturated carboxylic acid copolymer.

The moisture-proof layer containing a coupling agent used as a moisture-proofness improver in the present invention is a coating solution comprising an α-olefin / unsaturated carboxylic acid copolymer and a tabular pigment,
It may be formed by mixing a coupling agent, applying the obtained coating liquid on the surface of a paper support, and drying. Alternatively, the surface of the tabular pigment is treated with a coupling agent in advance,
It may be fixed on this surface. That is, as the method of using the coupling agent, both the integral blending method and the pretreatment method can be used. The integral blending method is a method in which a coupling agent is directly added to a coating liquid containing an α-olefin / unsaturated carboxylic acid copolymer and a tabular pigment. The pretreatment method is a method in which the tabular pigment is previously treated with a coupling agent, which includes a dry method and a wet method. The dry method is a method in which a powdery flat pigment is put in a mixer, and after preheating this, a coupling agent is added and the mixture is stirred at high speed under heating.
In this method, a coupling agent and a tabular pigment are added to a solvent or a mixed solution thereof, and the mixture is stirred at a high speed and then dried to obtain a powder. The integral blending method is slightly inferior to the pretreatment method in the use effect of the coupling agent, but is excellent in workability because there is no pretreatment step.

In the integral blending method or the wet pretreatment method, when the tabular pigment is treated in an aqueous treatment system, a methoxy group or an ethoxy group having relatively weak hydrophobicity is used as an alkoxy group in order to increase the water solubility of the coupling agent. ,
It is preferable to use an isopropoxy group, and it is preferable that the hydrophobic group portion of the coupling agent contains a hydrophilic epoxy group, amino group, or hydroxyl group. If the coupling agent is difficult to dissolve in water, a very small amount of surfactant may be used together.

The amount of coupling agent added is the amount of tabular pigment 1
The amount is preferably 0.1 to 5 parts by mass, more preferably 0.5 to 2 parts by mass with respect to 00 parts by mass. When the amount of the coupling agent used is less than 0.1 parts by mass, the effect may be insufficient due to insufficient coating of the tabular pigment surface with the coupling agent, and when it exceeds 5 parts by mass, The effect of the coupling agent may be saturated, which may be uneconomical.

When the hydrophobicity of the surface of the tabular pigment treated with the coupling agent becomes excessively high, when it is made into an aqueous dispersion, it thickens and cannot be applied, or dispersion becomes poor, resulting in aggregation. May occur. In this case, a surfactant or a polyacrylic acid-based dispersant, or a wetting agent such as isopropyl alcohol or sodium dialkylsulfosuccinate can be used for dispersion.

In the present invention, the organic amine compound and the polyamide compound used as the moisture resistance improver have a cationic property, and when they contact a tabular pigment exhibiting an anionic property, their soft agglomeration and lamination in parallel with each other. The orientation can be promoted and the moisture-proof performance of the moisture-proof layer can be improved.

In the present invention, the carboxylic acid group contained in the synthetic resin reacts with the organic monoamine, the organic polyamine, or the organic quaternary ammonium salt to give a hydrophobic property of the α-olefin / unsaturated carboxylic acid copolymer, Alternatively, water insolubility can be increased.

In the present invention, the organic amine compound used as the moisture resistance improver may be any of a primary amine compound, a secondary amine compound, a tertiary amine compound and a quaternary ammonium salt compound. Further, it may be either an organic monoamine or an organic polyamine.
Furthermore, the organic amine compound is a heterofunctional group other than the amino group,
For example, those having an epoxy group, a hydroxyl group, a carboxylic acid group, a nitrile group and the like are included. Such modified organic amine compounds include adducts of compounds having an epoxy group such as monoepoxy compounds and diepoxy compounds with amine compounds, adducts of compounds having hydroxyl groups such as ethylene oxide and propylene oxide with amine compounds, and acryl. Examples thereof include a Michael adduct of a nitrile and an amine compound, an adduct obtained by a Mannich reaction of a phenol compound, an aldehyde compound and an amine compound.

For the above-mentioned modification, 1) the toxicity of the amine compound such as irritating odor and skin irritation is reduced, 2) the viscosity of the amine compound is reduced, and 3) the molecular weight is increased to be weighed. There are effects such as reducing the error. The degree of modification of the amine compound is not particularly limited.

Examples of the organic amine compound used in the present invention are as follows. 1) Aliphatic polyamine (polyalkylene polyamine) or monoamine ethylenediamine, propylenediamine,
Diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, iminobis-propylamine, bis (hexamethylene) triamine, dimethylaminopropylamine, diethylaminopropylamine, aminoethylethanolamine,
Methyliminobispropylamine, Menthanediamine-
3, N-aminoethylpiperazine, 1,3-diaminocyclohexane, isophoronediamine, triethylenediamine, polyvinylamine, stearylamine, laurylamine and the like. 2) aromatic polyamine or monoamine m-phenylenediamine, 4,4'-methylenedianiline, benzidine,
Diaminodiphenyl ether, 4,4'-thiodianiline, dianisidine, 2,4-toluenediamine, diaminodiphenyl sulfone, 4,4 '-(o-toluidine), o-phenylenediamine, methylenebis (o-chloroaniline), m-amino Benzylamine, aniline, etc. 3) Aliphatic polyamines having an aromatic ring group or monoamine metaxylylenediamine, tetrachloroxylenediamine, trimethylaminomethylphenol, benzyldimethylamine, α-methylbenzyldimethylamine and the like. 4) Secondary amine N-methylpiperazine, piperidine,
Hydroxyethylpiperazine, pyrrolidine, morpholine, etc. 5) Tertiary amine tetramethylguanidine, triethanolamine, N, N'-dimethylpiperazine, N-methylmorpholine, hexamethylenetetramine, triethylenediamine, 1-hydroxyethyl-2-heptadecylglyoxalidine, pyridine, pyrazine , Quinoline, etc. 6) Quaternary ammonium salt diallyldimethylammonium chloride, hexyltrimethylammonium chloride, cyclohexyltrimethylammonium chloride, octyltrimethylammonium bromide, 2-
Ethylhexyl trimethyl ammonium bromide,
1,3-bis (trimethylammoniomethyl) cyclohexanedichloride, lauryldimethylbenzylammonium chloride, stearyldimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium chloride and the like. 7) Betaine compound, glycine compound, amino acid compound coconut oil alkyl betaine, lauryl dimethylamino acetic acid betaine, lauryl amidopropyl betaine, polyoctyl polyaminoethyl glycine, sodium lauryl aminopropionate and the like. Among the above organic amine compounds, it is preferable to use an aliphatic polyamine, an aliphatic polyamine having an aromatic ring group, or a modified polyamine.

The polyamide compound (also referred to as polyamide amine compound) used in the present invention is obtained by a dehydration condensation reaction of the above amine compound and a compound having a carboxylic acid group. For example, reaction product of tall oil and diethyltriamine, reaction product of dimer of linolenic acid and tetraethylpentamine, reaction product of triethylenetetramine and saturated dibasic acid (adipic acid, sebacic acid, isophthalic acid, terephthalic acid). Substances, reaction products of polymerized fatty acids and diethyltriamine, and the like. The molecular weight of these polyamide compounds is preferably about 1000 to 5000.

The organic amine compound or polyamide compound used in the present invention is preferably water-soluble, but even if it is water-insoluble, it can be emulsified or dispersed for use. Two or more of the above amine compounds or polyamide compounds may be mixed and used. Generally, the amine value of the organic amine compound or the polyamide compound is preferably 100 to 1000, but is not particularly limited.

In the present invention, the epoxy compound used as the moisture resistance improver may be a monoepoxy compound. This monoepoxy compound includes an aliphatic monoepoxy compound and an aromatic monoepoxy compound, for example, butylene oxide, octylene oxide, butyl glycidyl ether, styrene oxide, phenyl glycidyl ether, glycidyl methacrylate, allyl glycidyl ether, phenol polyethylene glycol. It can be selected from glycidyl ether, lauryl alcohol polyethylene glycol glycidyl ether, and the like.

The monoepoxy compound used in the present invention is preferably a water-soluble one, but even if it is insoluble, a surfactant or the like is added in an amount of 0.1 to 3 relative to the monofunctional epoxy compound.
It can be used by dispersing it in water by using it by mass%.

The above monoepoxy compound is used in an amount of 0.05 to 10 parts by mass, preferably 0.5 to 5 parts by mass, based on 100 parts of the synthetic resin component (a). When the blending amount of the monoepoxy compound is less than 0.05 parts by mass, the effect of improving moisture resistance may be insufficient, and when it exceeds 10 parts by weight, the effect of moisture resistance is saturated,
May be economically disadvantageous.

When the moisture resistance improver containing the above monoepoxy compound is used, the synthetic resin (a) used with it is a hydrophilic functional group (carboxyl group, such as acrylic acid or acrylamide) capable of reacting with the epoxy ring. It is preferable to include a copolymer containing a monomer having a group, an amide group, and a hydroxyl group.

In the present invention, the polyamide polyurea compound, the polyamine polyurea compound, the polyamide amine polyurea compound, and the polyamide amine compound used as the moisture resistance improver are (i) polyalkylene polyamine or alkylene polyamine, and (ii) urea. (Iii) dibasic carboxylic acid, and optionally (iv) an aldehyde, an epihalohydrin and a compound selected from α, γ-dihalo-β-hydrins (JP-B-59-32597). (Japanese Patent Application Laid-Open No. 4-10097). In the above synthesis, dibasic carboxylic acid (ii
When i) is used, a polyamide polyurea compound or a polyamide amine polyurea compound is obtained, and when not used, a polyamine polyurea compound is obtained. When aldehydes and epihalohydrins are used, it is preferable that the amount used is very small or self-crosslinking occurs in the synthesis process so that free methylol groups and epoxy groups hardly remain. In the above reaction, the number of urea (i
A polyamidoamine compound can be obtained by reacting a polyalkylene polyamine or alkylene polyamine (i) with a dibasic carboxylic acid without using i). Ingredient (iv)
The reaction amount of the aldehydes, epihalohydrins, and α, γ-dihalo-β-hydrins is preferably within the range of 5 to 300 mols based on 100 mols of the component (i).

Examples of the polyalkylene polyamine or alkylene polyamine used as the above component (i) include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, iminobispropylamine, 3-azahexane-1,6-diamine, 4, 7
-Diazadecane-1,10-diamine, ethylenediamine, propyldiamine, 1,3-propanediamine, hexamethylenediamine and the like. Of these, diethylenetriamine and / or triethylenetetramine are preferably used. These compounds (i) are used alone or as a mixture of two or more kinds. Further, one or more alicyclic amines such as cyclohexylamine and alicyclic epoxy compounds may be used in combination with the compound (i).

Examples of the urea used as the component (ii) include urea, thiourea, guanylurea, methylurea and dimethylurea. Among these, it is preferable to use urea. These urea compounds may be used alone or in combination of two or more.
The dibasic carboxylic acid used as the component (iii) has two carboxyl groups or groups derived from it in the molecule and may be a free acid, or an ester or an acid anhydride. It may be a thing or the like. The dibasic carboxylic acid may be an aliphatic, aromatic or alicyclic dibasic carboxylic acid. Specific examples thereof include succinic acid, glutaric acid, adipic acid, sebacic acid,
Examples thereof include maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid and the like. Further, polyesters having a free carboxylic acid group at the end, which are reaction products of dibasic carboxylic acid and glycols, may be used. These dibasic carboxylic acids may be used alone or in combination of two or more. The aldehydes used as the component (iv) include alkyl aldehydes such as formaldehyde and propyl aldehyde, glyoxal, propanedial and butanedial, and epihalohydrins such as epichlorohydrin and epibromohydrin. Furthermore, as the α, γ-dihalo-β-hydrins used as the component (iv), 1,3-dichloro-2-propanol and the like can be mentioned.

These aldehydes, epihalohydrins and α, γ-dihalo-β-hydrins may be used alone or in combination of two or more.

Further, as a monomer component, an alicyclic epoxy compound, an alkylating agent (general formula R—X; R = lower alkyl group, alkenyl group, benzyl group, phenoxyethyl group, etc., X = halogen atom), general formula R'-C (= Y) -N
A compound represented by H2 [R 'is an alkyl group or -NR'2 group, Y is an oxygen atom or a sulfur atom] may be reacted.

The above components can be reacted in any order, and the following method can be used as an example of the synthesis method. That is, alkylenediamine or polyalkylenepolyamine and ureas are subjected to a deammonification reaction, then the reaction product is dehydrated and condensed with dibasic carboxylic acids, and further ureas are subjected to a deammonification reaction to produce polyamidepolyurea. The compound is obtained. The polyamide polyurea compound is reacted with a compound selected from aldehydes, epihalohydrins and α, γ-dihalo-β-hydrins to obtain a polyamide polyurea-aldehyde (epihalohydrin) resin.

Aldehydes, epihalohydrins, α,
The γ-dihalo-β-hydrins are used for the purpose of adjusting the molecular weight and adjusting the water solubility, but it is preferable that the methylol group and the epoxy ring are self-crosslinked and hardly remain.

In the present invention, the polyamide polyurea compound, polyamine polyurea compound, polyamidoamine polyurea compound and polyamidoamine compound used as the moisture proofing agent show a slight cationic property in an aqueous coating solution, and therefore, they are anionic. It is considered that the tabular pigment having the property is softly aggregated in the process of forming the film, and at this time, these tabular grains are laminated and oriented parallel to each other. The improvement of the layered orientation of the tabular grains improves the moistureproof performance of the moistureproof layer. Further, among the above compounds, those having an epoxy ring and / or a methylol group in the molecule are included, but the content of these functional groups is very small, and the epoxy ring and the / Or because most of the methylol group-forming compounds self-crosslink,
The effect of these functional groups is negligible. Therefore, the moisture-proof layer containing the above compound as the moisture-proofness improver is easily disintegrated from the paper support during recovery and regeneration of the moisture-proof paper, and hardly impairs the disintegration property of the recycled pulp.

In the present invention, the moisture resistance improver is preferably used in an amount of 0.05 to 30 parts by weight based on 100 parts by weight of the synthetic resin and the tabular pigment in terms of weight. It is more preferably 0.5 to 20 parts by mass, and particularly preferably 1 to 10 parts by mass. The compounding amount is 0.
When the amount is less than 05 parts by mass, the moisture-proof property improving effect may be insufficient, and when it exceeds 30 parts by mass, the moisture-proof property improving effect may be saturated, which may be economically disadvantageous. Further, the moisture resistance improver used in the present invention may be composed of two or more kinds of compounds.

As the moisture-proof property improver used in the moisture-proof paper of the present invention, a crosslinking reaction agent and a coupling agent may be used in combination. In this case, the cross-linking reaction agent is a urea-formaldehyde condensation reaction product, a melamine-formaldehyde condensation reaction product, an aldehyde compound having 1 to 8 carbon atoms, an epoxy compound having one or more epoxy groups, a cross-linking reactivity One or more selected from a valent metal compound, an organic amine compound and a polyamide compound may be contained, and the coupling agent may be one or more selected from the aforementioned organoalkoxysilane compounds and organoalkoxy metal compounds. Can be included. The amount of carboxylic acid contained in the α-olefin / unsaturated carboxylic acid copolymer is more preferably 5 mol% or more in acid modification rate.

The coating amount of the moisture-proof layer is not particularly limited, but can be 0.
1 to 20 g / m ² is preferable, more preferably 1 to 15
g / ^{m 2,} and most preferably from 3 to 10 g / ^{m 2.} When the coating amount of the moisture-proof layer is less than 0.1 g / m ² , it is difficult to obtain a uniform coated surface and the moisture-proof property may be deteriorated, which is not preferable. On the other hand, if the coating amount exceeds 20 g / m ² , it is uneconomical because the moisture-proof property reaches a ceiling, and the proportion of the moisture-proof layer becomes large, so that the value as waste paper decreases.

The moisture resistance of the moisture-proof and rust-proof paper of the present invention can be controlled by selecting the constitution of the moisture-proof layer as described above according to the purpose of use such as the type of metal to be packaged and the conditions of use. In particular, as a moisture-proof rust-preventing paper that exhibits more rust-preventing property by maintaining moisture-proof property for a long time even under high humidity condition, a moisture-permeable (J
IS-Z-0208 cup method) is 200 g / m ^2.
-It is preferable to have a moisture-proof property of 24 hours or less. In addition, 100 g / m ² · 24 hr or less is more preferable, and 50 g
/ M ² · 24 hr or less is more preferable because the use is expanded.

In the moisture-proof coating composition of the present invention, if necessary, a dispersing agent such as polycarboxylic acid, a defoaming agent such as silicone,
A surfactant, a water retention agent, a color adjusting agent, etc. can be added.

The moisture-proof coating as described above is applied to the paper support to form a moisture-proof layer. The coating equipment is not particularly limited, but a method such as a blade coater, a bar coater, an air knife coater, or a slit die coater is preferable. In particular, for forming the moisture-proof layer, a coater such as a blade coater, a bar coater, an air knife coater, or a slit die coater that scrapes the coated surface is preferable because it promotes the orientation of the tabular pigment.

The paper support used in the present invention is not particularly limited as long as it contains pulp as a main component, and examples thereof include bleached kraft paper, unbleached kraft paper, fine paper, medium-quality paper, coated paper, Various types of paperboard, paper core paper, cardboard base paper, paper core paper, crepe paper, recycled paper, etc. are used. Among these, it is more preferable to use bleached kraft paper or unbleached kraft paper as a base material in order to obtain a moisture-proof rust-proof paper having sufficient strength for packaging. Further, in order to obtain excellent moisture resistance, it is preferable to use, as a base material, paper whose surface is smoothed by forced drying with a Yankee dryer or calendering. For example, it is so-called single piece or kraft paper. When the surface of the paper substrate having a high smoothness is used as described above, when the moisture-proof layer is formed by coating, the orientation of the tabular pigment in the thickness direction is uniform without disturbing the coated surface, Moreover, since it is easy to arrange them in parallel, the moisture-proof performance is remarkably improved. Further, from the viewpoint of preventing rusting of the metal product to be packaged, the pH is 6.5 to 7.5, the chloride ion concentration is 0.01% by mass or less, and the sulfate ion concentration is 0.01.
It is preferable to use a neutral paper having a content of not more than mass% as a base material. The basis weight of the paper base material used is not particularly limited, but is generally in the range of 30 to 300 g / m ² .
It is appropriately selected and used according to the purpose of use.

The rust preventive agent used in the present invention is a vaporized rust preventive agent in which a component having a rust preventive property is vaporized. More specifically, dicyclohexylammonium nitrite, dicyclohexylammonium caprylate, dicyclohexylammonium carbonate, diisopropylammonium nitrite, monoethanol ammonium benzoate, sodium benzoate, benzoic acid, caprylic acid, capric acid, isopropyl benzoate, benzoic acid. Butyl, butyl cinnamate, ammonium carbamate, monoethylamine, diethylamine, monoethanolamine, diethanolamine, triethanolamine, morpholine, methylmorpholine, ethylmorpholine, hexamethylenetetramine, benzotriazole, tolyltriazole, urea, thiourea, nitrite Examples include soda.

The rust preventive agent may be used by directly impregnating or coating it on a paper base material. But in general,
The above rust preventives may be used alone or in combination of any two or more thereof, and dispersed, dissolved or mixed in an aqueous system, a non-aqueous medium, an ionizing radiation curable substance, etc., and an adhesive, a penetrant, etc., if necessary. Is added to prepare a rust preventive paint, which is applied to a base material for use. The concentration of the above rust preventive paint is usually 5
It is desirable to adjust to the range of -80% by mass. Further, the adhesive in the paint is 0-2 with respect to 100 parts by mass of the rust preventive agent.
It is preferably used in the range of 00 parts by mass. Also,
The penetrant is preferably used in the range of 0 to 100 parts by mass with respect to 100 parts by mass of the rust inhibitor.

As the aqueous medium, water or a medium miscible with water such as methyl ketone, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, isobutanol, ethylene glycol or propylene glycol is used. A mixed solution may be mentioned.

As the non-aqueous medium, for example, benzene,
Toluene, xylene, hexane, cycloquexane, trichloroethylene, methyl ketone, methyl ethyl ketone,
Methyl isobutyl ketone, methyl acetate, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, isobutanol, n-hexanol, cyclohexaol, ethylene glycol ,Propylene glycol,
Diethylene glycol etc. are mentioned.

Examples of the ionizing radiation-curable substance include monomers, oligomers and prepolymers having an ethylenically unsaturated bond which are cured by electron beams or ultraviolet rays, and specific examples thereof include styrene, methyl acrylate, butyl acrylate and lauryl acrylate. Polyethylene glycol diacrylate, propylene glycol diacrylate, trimethylolpropane diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, hexanediol diacrylate, 1,2-
Examples thereof include butanediol diacrylate, a reaction product of an epoxy resin and acrylic acid, and a condensate of maleic acid, acrylic acid and diethylene glycol. When a monomer, an oligomer or a prepolymer having an ethylenically unsaturated bond is used for curing with ultraviolet rays, a photopolymerization initiator and optionally a sensitizer are added to the coating liquid.

Examples of the photopolymerization initiator include benzoquinone, phenanthrenequinone, naphthoquinone, benzoin butyl ether, benzoin and Michler's ketone. Examples of the sensitizer include triethanolamine, N-methyldiethanolamine, N, N-diethanolamine, N-methylmorpholine and the like. Examples of penetrants include alcohols such as isopropyl alcohol and isobutyl alcohol.

As the adhesive, a water-soluble binder or a latex binder is used when applied as an aqueous system, and an oil-soluble binder is used when applied as a non-aqueous system.

Examples of the water-soluble binder include water-soluble natural or semi-synthetic polymer compounds such as gelatin, albumin, casein, starch, ether starch, esterified starch, carboxymethyl cellulose, hydroxyethyl cellulose, agar, sodium alginate, and gum arabic. Polyvinyl alcohol, modified polyvinyl alcohol, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, ethylene / maleic anhydride copolymer, styrene / maleic anhydride copolymer, methyl vinyl ether / maleic anhydride copolymer, isobutylene / maleic anhydride Examples thereof include water-soluble synthetic polymer compounds such as copolymers.

Examples of the latex binder include styrene-butadiene latex, acrylonitrile.
Examples thereof include butadiene latex, acrylic acid ester latex, vinyl acetate latex, vinylidene chloride latex, and carboxy-modified (eg acrylic acid) latex thereof.

Examples of the oil-soluble binder include natural resins such as rosin, copearl, dalman, gilsonite, zein, hardened rosin, dimerized rosin, polymerized rosin, maleic acid resin, fumaric acid resin, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, Semi-synthetic resin such as ethyl hydroxyethyl cellulose, cellulose acetate propionate, cellulose acetate butyral, nitrocellulose, phenol resin, xylene resin, urea resin, melamine resin, ketone resin, coumarone / indene resin, petroleum resin, terpene resin, cyclization Rubber, chlorinated rubber, alkyd resin, polyamide resin, acrylic resin, polyvinyl chloride, polyvinyl acetate, vinyl chloride / vinyl acetate copolymer, chlorinated polypropylene styrene resin, epoxy resin Polyurethane resins, and polyvinyl butyral.

The rust preventive coating material is applied to the base paper by impregnation or coating. Generally, the coating is performed by using a coating machine such as a bar coater, a roll coater, a gravure coater, and an air knife coater. The coating amount of the rust preventive coating material is preferably 8 to 30 g / m ^{2 in} terms of solid content, and particularly preferably 10 to 15 g / m ² . The coating amount is 8
If it is less than g / m ² , the rust preventive effect may be insufficient.
If the coating amount exceeds 30 g / m ² , the surface of the rust-preventive paper may be sticky or crystals of the rust-preventive agent may be generated. Further, it is not preferable because the manufacturing cost becomes extremely high.

The composition of the moisture-proof and rust-proof paper in the present invention is a laminate comprising a paper support and a moisture-proof layer, and the rust-preventive agent is
It may be contained in at least one part of the laminate. The layer structure of the laminate can be arbitrarily selected according to the situation within the scope of the present invention. For example, one having a moisture-proof layer provided on a paper support containing an anticorrosive agent by impregnation or the like, one having a constitution of paper support / rust-preventive agent coating layer / moisture-proof layer, moisture-proof layer / paper support / proof Rust coating layer, paper support / moisture-proof layer containing rust inhibitor, paper support / moisture-proof layer / rust-preventing coating layer, paper support / Examples thereof include a moistureproof layer / paper support structure in which at least one layer contains a rust inhibitor. Two or more layers of the rust preventive coating layer and the moisture proof layer may be provided in the laminate. The moisture-proof and rust-proof paper of the present invention has a layer structure of moisture-proof layer / paper support / rust-preventive agent layer, which is provided with a moisture-proof layer on one side of a paper base material and a rust-preventive agent layer on the opposite side. Are more preferably used. Moisture-proof and rust-proof paper having such a structure is not only simple and economically obtainable, but the humidity-proof layer and the rust-preventive agent layer are provided on the outer side of the package and the inner side of the package, respectively. At the same time as preventing it, the rust preventive agent is vaporized inside the package, and at the same time, the external moisture barrier layer has gas barrier properties at the same time, so the rust preventive agent can be trapped inside the package and prevented from diffusing into the outside air. The rust preventive effect of the rust preventive agent can be exhibited more efficiently and continuously.

[0085]

EXAMPLES The present invention will be specifically described below with reference to examples, but the following examples do not limit the present invention. Unless otherwise specified, the following parts are parts by mass.

<Moisture-proof coating 1> 100 parts of water with natural mica (muscovite, FA-500, manufactured by Yamaguchi Mica Industry Co., Ltd., composition formula K ₂ O.3Al ₂ O ₃ .6SiO ₂ .2H ₂ O, average 100 parts of a particle diameter of 18 μm and an aspect ratio of 20 was added, and to this was added a carboxylic acid-modified SBR latex (S1X
2, manufactured by Nippon Zeon Co., Ltd., acid modification rate of about 20%, Tg18
C., 300 parts of solid content concentration 50%) was added and stirred to prepare a moisture-proof coating 1 (a tabular pigment and a carboxylic acid-modified SBR).
Blending ratio of latex = 40/60).

<Moisture-Proof Coating 2> An acrylic ester copolymer emulsion (Cybinol RX-61, manufactured by Saiden Chemical Co., Ltd., Tg 24 ° C., solid content concentration 40%) was used as a moisture-proof coating 2.

<Example 1> Unbleached kraft paper (70 g / m
⁽² , 100 μm thick), the moisture-proof coating 1 was applied to one side as a solid content by a Mayer bar so that the coating amount was 10 g / m ^2, and then dried at 130 ° C. for 2 minutes to obtain a moisture-proof paper. Subsequently, a rust preventive coating material prepared by dissolving 20 parts by mass of sodium nitrite and 20 parts by mass of monoethanolammonium benzoate in 60 parts by mass of water was coated on the back surface of the moisture-proof paper as a solid content to give a coating amount of 1
After coating with a Mayer bar to give 0 g / m ² , 115
It was dried at ℃ for 2 minutes to obtain a moisture-proof and rust-proof paper.

<Comparative Example 1> Moisture-proof coating 2
Moisture-proof and rust-proof paper was obtained in the same manner as in Example 1 except that the formation was carried out.

<Comparative Example 2> Unbleached kraft paper (70 g / m
Moisture-proof and rust-proof paper was obtained in the same manner as in Example 1 except that a moisture-proof paper obtained by extruding and laminating polyethylene to a thickness of 15 μm was laminated as a moisture-proof layer on one surface ( ² , 100 μm thickness).

[0091]

[Table 1]

<Evaluation method> 1) Anticorrosion test (1) Vaporization test method According to JIS-Z-1535.5.4, the vaporization rust preventive test. (2) Contact test method According to the contact rust prevention test according to JIS-Z-1535.5.6.

2) Water vapor permeability JIS-Z-0208 (cup method) Method B (40 ° C 90%
RH) with the moisture-proof coated surface facing outside. 20
If it is 0 g / m ² · 24 hr or less, it is evaluated as having moisture resistance.

3) Disaggregation The equivalent of 45 g of moisture-proof and rust-proof paper was cut into about 5 cm square
Of TAPPI disaggregation standard machine (disintegrator
-Using a 2 liter container) in 1500 g of water for 20 minutes
I disaggregated. Laboratory handmade machine from the obtained slurry
Basis weight 60g / m ^TwoThe sheet of was produced. Obtained by the above
Of undisintegrated material (film pieces or paper pieces)
The size is visually evaluated and the size of the undisassembled fragments present on the sheet is large.
If the major axis is 5 mm or less, it is larger than 5 mm.
The presence of undisaggregated pieces was designated as x. Large undisassembled fragments
It is said that if the size is 5 mm or less, it can be reused as waste paper.
It is priced.

[0095]

Industrial Applicability According to the present invention, it has anticorrosive properties and water disintegration properties that can be recycled as waste paper, and the contents of the package can be protected from moisture even under high humidity conditions or under water. It has become possible to provide a moisture-proof and rust-proof paper having high moisture resistance and water resistance.

Claims (3)

[Claims] 1. A moisture-proof paper having a moisture-proof layer containing a synthetic resin and a tabular pigment on at least one surface of a paper support, wherein the moisture-proof paper contains a vaporizable rust preventive agent. 2. The moisture-proof rust-preventive paper according to claim 1, wherein the tabular pigment is at least one selected from phyllosilicate minerals and highly swelling clay minerals. 3. The moisture-proof and rust-proof paper according to claim 1 or 2, wherein the paper support has a moisture-proof layer on one side and a rust-preventive agent coating layer on the other side.