JP2002337298A - Moistureproof laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moistureproof laminate being moistureproof paper reutilizable as used papers and having dissociable properties, drastically enhanced in moistureproof properties under an ultrahigh humidity condition and excellent in moistureproof properties and dissociable properties even in a low coating amount. SOLUTION: In the moistureproof laminate wherein an anchor layer is provided on at least the single surface of a paper support and a moistureproof layer containing a synthetic resin and a plate-shaped pigment is provided on the anchor layer, the amount of alkali metal ions in the anchor layer is 0.01-5% by weight of the solid of the anchor layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture-proof paper which can be reused as used paper (having water disintegration properties). It is possible to dramatically increase the moisture resistance of conventional products compared to conventional products.
An object of the present invention is to provide a moisture-proof laminate excellent in defibration properties.

[0002]

2. Description of the Related Art Conventionally, winding of high quality paper, bleached kraft paper, unbleached kraft paper, various coated papers, etc. and packaging of high quality paper and coated paper plain paper have been conducted to prevent moisture absorption of products. A wrapping paper roll obtained by coating, laminating or internally adding a polyolefin-based polymer compound such as polyethylene, polypropylene, etc. on a paper and winding the wrapping paper having moisture resistance and water resistance into a roll shape as it is or as desired. Cut to size and used. For base paper for heavy bags such as cement bags, resin bags, salt bags, sugar bags, feed bags, fertilizer bags, garbage bags, etc. Polyolefin-laminated paper made of polyethylene, polypropylene, etc. laminated on kraft paper, which requires moisture resistance and strength to transport
(Hereinafter referred to as poly-laminate paper) and kraft paper are used. Further, a corrugated cardboard is provided with a moisture-proof layer formed on a liner base paper for corrugated cardboard to make the cardboard water-resistant and moisture-proof. However, these polylaminate papers are problematic because they are not sufficiently disintegrated in water even if collected and reused as used paper after use, and cannot be reused as used paper. In addition, even if used poly-laminate paper is discarded, there is a concern that it may cause environmental pollution because it can only be disposed of by incineration or landfill, and there are many problems at present.

[0003] As described above, conventional moisture-proof papers have problems, and development of moisture-proof papers to replace them is urgent. As one of the techniques for this purpose, there has been proposed a technique for obtaining a moisture-proof paper by applying a composition obtained by blending 5-200 parts by weight of a wax with 100 parts by weight of a butadiene-based latex.
(Japanese Patent Publication No. 55-22597). However, since this technique uses wax, there is a problem of "slip" that occurs when the moisture-proof paper is stacked and a problem of printability when printing on the moisture-proof paper. Also, with respect to moisture resistance, it is difficult to obtain a moisture resistance comparable to that of polyethylene laminated paper when applied to paper with a low coating amount. Also, a paraffin wax having a specific melting point, an esterified product of maleated or fumarated rosin and a polyhydric alcohol, a wax emulsion mainly containing liquid polybutene and rosin, or a mixture of the wax emulsion and a synthetic rubber-based latex A method for producing a moisture-proof paper, which is applied to the surface of a fibrous base material such as high-quality paper or kraft paper and dried under heating, has also been proposed (JP-A-61-47896). However, when the moisture-proof paper obtained by this method is in the form of a roll, the back surface of the support is slippery because a part of the wax component contained in the moisture-proof layer is slightly leached out, so that the heavy-weight packaged with the moisture-proof wrapping paper is used. When loading, unloading, or transporting rolled paper, a gap between the wrapping paper and its contents may occur, or in severe cases, the wrapping paper may be torn or the contents may fall off. I do. Further, there is a problem that the label is immediately peeled off even when a label is attached to the surface of the moisture-proof layer containing such a wax. Further, an adhesive which is usually used at the time of packaging causes poor adhesion. In particular, general-purpose vinegar emulsion-based adhesives cannot be applied due to repellency, or even if they can be applied, they have no adhesiveness. Therefore,
Very limited adhesives must be used, such as hot melt adhesives that are liquid and strong at room temperature.
However, such a hot-melt adhesive has a problem that the workability is poor and the cost is high because there is only stickiness at room temperature and there is only a large block.
Also, there is a method of bonding using an adhesive tape, but compared to bonding with an adhesive, when using an adhesive tape,
There is a serious disadvantage that the workability at the time of packaging is significantly inferior,
At present, it is used only for specific applications.

[0004] In order to solve these problems,
A moisture-proof paper having a non-slip layer made of an amphoteric compound on the back surface of a support has been proposed (Japanese Patent Publication No. 56-18712). However, when the sheet of the moisture-proof laminate having the moisture-proof layer on the support surface and the anti-slip layer on the back surface is finished as a roll, when the winding pressure increases, the anti-slip layer pigment damages the surface of the moisture-proof layer and causes the moisture-proof performance. Degradation occurs. For this reason, it is necessary to lower the winding pressure. However, the lowering of the winding pressure makes it impossible to manufacture a long winding due to the occurrence of slippage during winding, or significant work in the subsequent process due to uneven winding side surfaces. However, there is a problem that a decrease in sex is accompanied. As mentioned above,
At present, there is no moisture-proof paper that has a disintegration property and contains wax having a moisture-proof property superior to that of a plastic film and does not cause a problem due to slippage of a package. Also, as a moisture-proof paper that does not use wax,
The present inventors provide a moisture-proof laminate in which a moisture-proof layer comprising a flat pigment and a synthetic resin latex is provided on a paper support (Japanese Patent Application Laid-Open No.
21096). In the present invention,
The pigment itself is considered to be impermeable to water vapor, for example, a flat pigment such as muscovite is mixed with a polymer such as a synthetic resin latex to form a moisture-proof layer. The moisture-proof mechanism is that the water vapor transmission area is small in a plane, and the plate-like pigments are arranged in parallel in the thickness direction parallel to the surface of the moisture-proof layer. Since the pigment is transmitted while bypassing the pigment (curved path effect), the permeation distance of water vapor is increased, and as a result, the moisture-proof performance is greatly improved.

[0005] However, according to the present invention, the coating amount is 30 g /
m²15 to 60 g / m²・ Prevention in the range of 24 hours
It is very effective in producing wet paper, but requires less coating.
When it is reduced, the moisture resistance is reduced, and the coating amount is 10 g / m.²Below
200g / m²・ More than 24hr and moisture-proof paper
Practical use becomes difficult. Conversely, to improve moisture resistance
When the coating amount is increased, the percentage of the moisture-proof layer on the moisture-proof paper increases.
The problem is that the value as waste paper decreases
is there. From this, it is preferable that the coating amount is small.
Also, α-olefin / unsaturated carboxylic acid copolymer copolymers
Lucari aqueous solution (alkali-soluble resin) and α-olefin
.Prevention of emulsion of unsaturated carboxylic acid copolymer
The coating amount of the moisture-proof paper on which the wet layer is formed is 30 g / m.²With moisture permeability
The degree is 30g / m ²・ Exhibits around 24 hours, but
Can be redissolved due to strong film similar to body and polyethylene film
And cannot be reused as used paper. for that reason
In addition, low α-olefin and unsaturated carboxylic acid
Protection consisting of a mixture of a molecular weight copolymer and a vinyl emulsion polymer.
There is a method of providing a wet resin layer (JP-A-2000-805).
No. 93). This method can certainly disintegrate the moisture barrier
However, the disintegrated pieces are large and can be used as waste paper.
Is still inadequate. In addition, α-olefin / unsaturated
The melting point of the rubonic acid copolymer is 100 ° C. to 140 ° C.
In the drying process of papermaking,
The disaggregated pieces are fused and paper cannot be manufactured.
No. 5 to 15 g / m²Moisture proof is not enough with low coating amount
Minutes are another problem. High swelling
Moisture-proof coating composition composed of clay mineral and aqueous dispersion of synthetic resin
Moisture-proof paper having a moisture-proof layer formed of a product
0-303026, 2000-290895
Report), but the humidity is 100% or more (ultra-high humidity
Degree) is insufficient, and the coating amount is 15 g /
m²If less than less, the moisture resistance becomes insufficient.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a moisture-proof paper which can be reused as used paper (having water disintegration properties) and which has a remarkably improved moisture-proof property at an ultra-high humidity and a moisture-proof property even at a low coating amount. The present invention provides a moisture-proof laminate excellent in properties and defibration properties.

[0007]

The present invention employs the following method to solve the above-mentioned problems. That is, the first of the present invention is:
An anchor layer is provided on at least one side of a paper support, and in a moisture-proof laminate having a moisture-proof layer containing a synthetic resin and a flat pigment on the anchor layer, the amount of alkali metal ions in the anchor layer is based on the solid content of the anchor layer. 0.01-5% by weight
Is a moisture-proof laminate.

[0008] A second aspect of the present invention is that the coating amount of the anchor layer is 0.1 to ²⁰ g / m ² and the coating amount of the moisture-proof layer is 0.1 g / m ^2.
The moisture-proof laminate according to the first aspect of the present invention, which has a weight of 積 層 20 g / m ² .

A third aspect of the present invention is the moisture-proof laminate according to the first or second aspect of the present invention, wherein the tabular pigment is at least one selected from phyllosilicate minerals and highly swellable clay minerals.

A fourth aspect of the present invention is that the amount of alkali metal ions in the moisture-proof layer is 0.01 to 1% by weight based on the solid content of the moisture-proof layer.
The moisture-proof laminate according to the first to third aspects of the invention.

A fifth aspect of the present invention is the moisture-proof laminate according to the first to fourth aspects of the present invention, which has an overcoat layer on the moisture-proof layer.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The present inventors first confirmed that an anchor layer was necessary in order to obtain a moisture-proof layer having both disintegration and moisture-proof properties with a small coating amount, and in developing such a moisture-proof layer, A method was studied in which an anchor layer containing a synthetic resin was formed on one side of a paper substrate, and a moisture-proof layer composed of a flat pigment and a synthetic resin was formed on the anchor layer. For example, unbleached kraft paper having a basis weight of 70 g / m ² as a paper base, 10 g / m ^{2 of} a composition comprising SBR latex and kaolin as an anchor layer, and an α-olefin / unsaturated carboxylic acid copolymer as a moisture-proof layer 5 g of a composition comprising a tabular pigment
m ² is provided. The moisture-proof paper obtained in this way is 40 ° C. 9
The moisture permeability of 0% exerts sufficient moisture resistance with a value of about 40g / m 2 ^· 24hr, moreover defibration properties was good. However, the humidity is over 90% and 100%
And become close state, moisture permeability of 100g ^/ m 2 · 24hr
That's all. A humidity of 100% is assumed to be such that when stored in a warehouse during the rainy season, it is rapidly cooled at night and condensed on the wrapping paper. If the moisture permeability at 100% humidity is 100 g / m ² · 24 hr or more, this is a level at which practical problems occur.

The inventors of the present invention have conducted intensive studies and have found that the influence of the hydrophilic component, particularly the alkali metal ion component, contained in the anchor layer is large, and that this has an adverse effect on the moisture-proof property especially in an ultra-high humidity atmosphere. I found it. The effect of the alkali metal ion component is that the coating amount of the moisture-proof layer is 2%.
It has been found that the coating amount becomes remarkable at a low coating amount of 0 g / m ² or less, further 15 g / m ² or less. The present inventors have disclosed in
Japanese Patent Application Laid-Open No. -50388 discloses that the moisture-proof property, particularly under ultra-high humidity conditions, is adversely affected by the amount of the alkali metal ion component contained in the moisture-proof layer. However, it was impossible to imagine that the alkali metal ions of the base material and the anchor layer affect the moisture resistance.

The influence of the alkali metal ions on the moisture resistance is considered as follows. The moisture permeability coefficient of a film-like thin film (here, a moisture-proof layer formed on a 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 the diameter of the water molecule. Strictly speaking, dissolution and diffusion can be analyzed mathematically only if the diffusion satisfies Fick's law and the dissolution follows Henry's law. The permeation process (dissolution and diffusion) of water molecules into a polymer membrane often does not follow Fick's law or Henry's law, but analyzing the permeation process separately into dissolution and diffusion will elucidate the permeation mechanism. Important above. The solubility coefficient is the solubility of steam at a certain steam pressure in a coating film. In other words, it means the water content of the coating film at a certain vapor pressure, and when the dissolution follows Henry's law, the solubility of water molecules is proportional to the partial pressure of water vapor. The solubility coefficient is represented by S = C / p (S: solubility coefficient, C: concentration of water molecule, p: partial pressure of water vapor), and is expressed as the amount of water when the partial pressure of water vapor contained in 1 g of the polymer membrane is 1 cmHg. Often represented. It can be said that the larger the solubility coefficient is, the easier it is to contain water. 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 more easily water molecules in the coating film move and diffuse. When the permeation satisfies Fick's law, the flow velocity J (the amount of substance passing through a unit area perpendicular to the flow direction per unit time)
Is proportional to the concentration gradient dC / dx of the transmitting substance. 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 transmission coefficient is the product of this solubility coefficient and the diffusion coefficient. In order to reduce the permeability coefficient, that is, to increase the moisture resistance, it can be achieved by reducing the solubility coefficient or the diffusion coefficient. Reducing the solubility coefficient can be achieved by 1) increasing the orientation of the polymer film or increasing the crystallinity, and 2) reducing the number of hydrophilic functional groups and hydrophilic components. The diffusion coefficient is 1) to increase the orientation of the polymer film or to increase the crystallinity, 2) to increase the rigidity of the polymer chain or to increase the glass transition temperature, or 3) to increase the cohesive energy density of the polymer. And so on. Thus, the transmission coefficient can be represented by the product of the solubility coefficient and the diffusion coefficient (dissolution diffusion theory of transmission). The permeability coefficient can be determined from the moisture permeability and the thickness of the film. The solubility coefficient is determined 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 part of the moisture absorption or dehumidification curve. If two coefficients are obtained, the remaining one coefficient can be obtained from the equation of P = DS.

When a hydrophilic component (alkali metal ion or water-soluble compound) is present in the moisture-proof layer, the solubility coefficient is increased and the moisture-proof property is deteriorated. In addition, when the amount of adsorption of the polymer film increases due to a higher dissolution coefficient, the polymer film is plasticized by moisture, and the polymer chains move more easily (the glass transition temperature decreases). In many cases, diffusion becomes easy and the diffusion coefficient becomes large. For this reason, when 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 deteriorates synergistically. In particular, this phenomenon becomes remarkable when the humidity is high. Specifically, when the relative humidity is 90% or more, the adverse effect of the hydrophilic component on the moisture-proof property increases. When there is a hydrophilic component in the anchor layer,
It is considered that the hydrophilic component in the anchor layer oozes and migrates into the moisture-proof layer when the moisture-proof layer is formed, so that the solubility coefficient and the diffusion coefficient are increased, and the moisture-proof property is deteriorated. In particular, when the moisture-proof paint that forms the moisture-proof layer is water-based, the moisture-proof paint is applied on the anchor layer, and until the moisture-proof paint is dried, the hydrophilic component of the anchor layer is dissolved by the moisture in the moisture-proof paint, so that the moisture-proof paint in the moisture-proof layer is removed. It is presumed that the hydrophilic component diffuses into the water. Also,
If an alkali metal is present in the anchor layer, it is conceivable that even after the moisture-proof layer has formed a coating film, the alkali metal ions are gradually transferred to the moisture-proof layer by the absorbed moisture.
The present inventors have also found that the influence of the hydrophilic component of the anchor layer increases as the coating amount of the moisture-proof layer decreases. The present inventors have found that among the hydrophilic components, alkali metal ions have the most adverse effect on the moisture-proof property.

The alkali metal ion is lithium ion
(Li⁺), Sodium ions (Na ⁺), Potassium
ON (K⁺), Rubidium ion (Rb⁺),cesium
Ion (Cs⁺), Francium ion (Fr)⁺)
Lithium ion (Li⁺),sodium
Ion (Na⁺), Potassium ion (K⁺) Is common
Yes, especially sodium ions (Na⁺) Often. Arca
Li metal ions are hydroxylated alkali metal ions in the moisture barrier
Substances, carbonate compounds, halogen compounds, sulfates, phosphates,
Or has sulfuric acid, carboxylic acid, phosphoric acid, nitric acid group
It is thought to be present in the form of a neutral salt with the compound. This
Alkali metal ion-derived compounds such as
Which are hygroscopic compounds. Hygroscopicity is alkali metal ion
It depends greatly on the type of ion and counter ion. For example, charcoal
Potassium acid begins to absorb moisture rapidly from about 30% humidity
You. Sodium chloride starts to absorb moisture when the humidity is around 60%
Start. Sodium benzoate with humidity over 90%
Absorb moisture. Therefore, if the relative humidity is higher than the humidity
This has a negative effect on moisture resistance. Especially 90% humidity
Above this, the moisture absorption tends to increase exponentially.
And more than 5 times the weight of the alkali metal compound
Some absorb moisture.

The anchor layer in the present invention is not particularly limited as long as the alkali metal ion content is 0.01 to 5% by weight based on the solid content of the anchor layer. The alkali metal ion content is more preferably 0.02 to 4% by weight, more preferably 0.03 to 3% by weight, and most preferably 0.03 to 1% by weight. When the amount of the alkali metal ion is less than 0.01% by weight, the effect on the moisture-proof property reaches a plateau. On the other hand, when the amount of alkali metal ions exceeds 5% by weight, the moisture resistance deteriorates. As a method for quantifying the amount of alkali metal ions, an atomic absorption method or an ion chromatography method is generally used, but the amount of alkali metal ions in the present invention is a value measured by an ion chromatography method.

The structure of the anchor layer preferably includes a resin or a resin and a pigment. The resin is not particularly limited, but examples thereof include a styrene-butadiene-based copolymer synthetic resin, a methacrylate-butadiene-based copolymer synthetic resin, an acryl-styrene-based copolymer synthetic resin,
Acrylic ester synthetic resin, polyester synthetic resin, acrylonitrile synthetic resin, polyvinyl alcohol synthetic resin, ethylene vinyl alcohol synthetic resin, vinyl acetate synthetic resin, ethylene vinyl acetate copolymer synthetic resin, vinyl chloride resin , Vinylidene chloride resin, starch natural resin, cellulose natural resin, urethane resin, polyamide resin, olefin resin,
There is no particular limitation as long as the resin has a binder function, such as an olefin / unsaturated carboxylic acid copolymer resin or a styrene resin. These resins are preferably used in the form of an aqueous emulsion, dispersion or aqueous solution. The use of a hydrophilic component, particularly a low-molecular-weight hydrophilic component, is unavoidable when the resin is converted to an aqueous system, but it is preferable to use a minimum amount. Alkali metal ions are necessary when emulsified or used as an aqueous solution, but can be replaced by ammonia or ammonium ions in many cases. Ammonia volatilizes together with water vapor due to heat at the time of forming the anchor layer and hardly remains in the anchor layer, so that it does not affect the moisture resistance. Therefore, it is preferable to use ammonia or ammonium ions instead of alkali metal ions.

Since the anchor layer itself is not required to have a moisture-proof property, there is no limitation on the moisture-proof property of the anchor layer. However, it is preferable that there is no pinhole or hole in which the moisture-proof paint easily penetrates and the moisture-proof paint component reaches the substrate. Further, an anchor layer paint capable of covering pores and irregularities of the substrate is preferable. Further, a material that does not cause repelling or aggregation when a moisture-proof paint is applied is preferable.

The anchor layer may contain a pigment. The pigment is not particularly limited, but is preferably a pigment having a particle diameter equal to or less than the total thickness of the anchor layer and the moisture-proof layer. In the case of a pigment having a particle diameter larger than the thickness of the anchor layer and the moisture-proof layer, the pigment protrudes from the moisture-proof layer and penetrates the moisture-proof layer. In this case, water vapor may permeate the pigment itself or the interface of the pigment, which is not preferable. The size of the particle diameter is 50 μm or less,
Preferably it is 30 μm or less, more preferably 20 μm or less. There is no particular limitation on the shape of the particles, spherical, plate-like,
Pigments of any shape, such as cubic, spindle, fibrous, and complex sugar, can be used. Specific examples of pigments include calcium carbonate, barium sulfate, titanium dioxide, magnesium hydroxide, magnesium oxide, magnesium carbonate,
Pigments such as aluminum hydroxide, aluminum oxide, silicon dioxide (silica, colloidal silica), kaolin, clay, mica, smectite clay, talc, zinc oxide, satin white, styrene particles, acrylic ester particles, polyolefin particles, etc. Organic pigments.

The use of a pigment together with a resin has the effect of improving the disintegration of the anchor layer. In general, when a coating layer made of only a hydrophobic resin having good film-forming properties is formed, the coating layer becomes strong and often does not become fine due to mechanical shearing action in water. Therefore, a method of improving the disintegration property by making the resin itself hard or brittle is used, but in that case, the selection of the resin is narrowed. However, the disintegration of the anchor layer itself can be improved by incorporating a pigment. This is presumably because the pigment in the anchor layer serves as a starting point of destruction, and the anchor layer becomes fine due to mechanical shearing action.

The ratio of the resin and the pigment in the anchor layer is not particularly limited, but is preferably resin / pigment = 1/99 to 99/1, particularly preferably 10/90 to 90/10. Both resins and pigments may be used in combination of two or more. Further, in addition to the resin and the pigment, a dispersant, a viscosity adjuster, a color adjuster, a cross-linking agent, a water-proofing agent, and the like may be used in combination as the anchor layer.

The origin of the alkali metal ions contained in the anchor layer is a component or an additive used when synthesizing the synthetic resin, an additive necessary for emulsifying and solubilizing the synthetic resin, and a dispersant used when dispersing the pigment. In addition, a viscosity modifier such as a synthetic resin aqueous solution / pigment dispersion, or an anchor layer paint, and impurities contained in a pigment or a synthetic resin can be considered. In particular, aqueous liquids of synthetic resins (emulsions and aqueous solutions)
The additives used vary depending on the synthesis method and the type of resin, and there is a great difference in the amount of alkali metal ions in each emulsion. In addition, the type of the pigment dispersion varies greatly in the type of the pigment dispersion as well as the type of the dispersant and the amount of alkali metal ions derived from impurities contained in the pigment. Therefore, the amount of alkali metal ions in the anchor layer paint for forming the anchor layer cannot be easily predicted.

In the moisture-proof laminate of the present invention, the coating amount of the anchor layer is not particularly limited, but is preferably 0.1 to 20 g / m ² , more preferably 0.5 to 15 g / m ² , and particularly preferably 1 to 10 g / m ² . 0.1 g coating amount
If it is less than / m ^{2, the} effect of filling the holes and irregularities of the base material with the anchor layer is small, so that when the moisture-proof layer is applied, the effective film thickness becomes small and the moisture-proof property becomes poor. In addition, the coating amount is 2
If it exceeds 0 g / m ^2, the effect of providing the anchor layer will level off, which is not preferable. The coating amount of the moisture-proof layer is not particularly limited, but is preferably 0.1 to 20 g / m ² , more preferably 1 to 15 g / m ² , and most preferably 3 to 10 g / m ² . The coating amount of the moisture-proof layer is 0.1 g / m
^If it is less than ² , the moisture resistance is poor, which is not preferable. On the other hand, if the coating amount exceeds 20 g / m ² , the moisture resistance is uneconomic because it reaches a peak, and the ratio of the moisture-proof layer in the moisture-proof laminate is increased, thereby deteriorating the value as waste paper.

The resin which can be used in the moisture-proof layer of the present invention is not particularly limited, as long as it forms a continuous film without pinholes and is moisture-proof. As a measure of moisture resistance, a single resin film (20μ
m thickness) at 40 ° C. and 90% is 1000 g /
m less than ² · 24hr, preferably 500g ^/ m 2 · 24h
less than r, and more preferably less than 200g ^/ m 2 · 24hr. Specific examples of the resin include a styrene / butadiene copolymer synthetic resin, a methacrylate / butadiene copolymer synthetic resin, an acrylic / styrene copolymer synthetic resin, an acrylic ester synthetic resin, a polyester synthetic resin, and an acrylonitrile synthetic resin. 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 Examples include unsaturated carboxylic acid copolymer resins and styrene resins.

Among them, vinyl polymers such as styrene / butadiene copolymer synthetic resin, acryl / styrene copolymer synthetic resin, and olefin / unsaturated carboxylic acid copolymer resin are preferable from the viewpoint of moisture resistance. is there. In addition, a biodegradable resin or a resin derived from a natural product also forms a continuous film alone, and has the above moisture-proof property (1000 g / m ² · 24 h).
r) or less can be used as the moisture-proof layer forming resin of the present invention.

The resin is easy to handle because of its pigment miscibility and viscosity as a coating material, and further, it is possible to control the film forming property of the coating film by drying conditions after coating.
Because you can control the balance between moisture resistance and disintegration,
It is preferred to use it in the form of an emulsion polymer. The vinyl emulsion polymer used in the present invention is obtained by emulsion polymerization of a vinyl monomer, and generally has a high molecular weight such as a molecular weight of several hundred thousand to several million. . The vinyl-based emulsion polymer is preferably in the form of a latex (emulsion) dispersed in an aqueous medium, that is, the one obtained by emulsion polymerization. The vinyl monomers used to obtain the vinyl emulsion polymer include aromatic vinyl monomers, aliphatic conjugated diene monomers, unsaturated carboxylic acid monomers, and other copolymerizable monomers. Dimer. 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 as vinyl emulsion polymer. No.

The aromatic vinyl monomer is capable of imparting appropriate hardness and water resistance to the resulting vinyl emulsion polymer. Can be.
Styrene is particularly preferred, and styrene is 30% by weight.
The vinyl emulsion polymer contained as a constituent monomer as described above,
The present invention is particularly preferable because the desired effects can be efficiently exhibited. The aliphatic conjugated diene monomer is
It imparts appropriate flexibility to the obtained vinyl emulsion polymer, for example, 1,3-butadiene, 2-methyl-
Examples thereof include 1,3-butadiene and 2-chloro-1,3-butadiene, and 1,3-butadiene is particularly preferable.

The unsaturated carboxylic acid monomer is effective for increasing 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,
Monobutyl fumarate and monobutyl maleate, such as an unsaturated polycarboxylic acid alkyl ester having at least one carboxyl group, and further as other acidic monomers for the same purpose,
Acrylamide propane sulfonic acid, sodium sulfoethyl acrylate, unsaturated sulfonic acid such as sodium sulfopropyl methacrylate or a salt thereof, and the like, among which acrylic acid, methacrylic acid, itaconic acid, fumaric acid and the like It is suitably used in the present invention.

Examples of other copolymerizable monomers include 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 such as acrylamide, methacrylamide, N-methylolacrylamide and diacetoneacrylamide, and derivatives thereof, 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 acrylamide as an unsaturated carboxylic acid amide and derivatives thereof Is preferably used.

As the olefin constituting the olefin / unsaturated carboxylic acid copolymer resin usable 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.

Ethylene and acrylic acid or methacrylic acid
The weight average molecular weight of the copolymer (hereinafter, both are referred to as (meth) acrylic acid), and further, the copolymer of ethylene and (meth) acrylic acid is preferably 5,000 to 100,000, and 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 that the moisture-proof surface slips, or the moisture-proof surface of the moisture-proof paper and the back surface, or the moisture-proof surface and the packaged contents, etc. (Phenomenon of wearing or sticking)), which is not preferable. If the weight average molecular weight exceeds 100,000, production becomes difficult, and the effects on moisture resistance, blocking resistance, and slip resistance level off.

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 properties. Examples of commercially available products that can be used as the latex-type olefin / unsaturated carboxylic acid copolymer described above include Hitec S-3121, 7024, 3125, and 3123.
And 3127 (both are trade names manufactured by Toho Chemical Industry Co., Ltd.)
And the like.

Further, an olefin / unsaturated carboxylic acid copolymer resin which is made water-soluble with an alkali (alkali-soluble type) is also preferable from the viewpoint of film-forming properties. Examples of the alkali include amines such as sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia, and alkanolamines. As described above, a large amount of alkali metal ions in the moisture-proof layer adversely affects moisture-proof properties. In view of moisture resistance, ammonia and amines are preferred. In particular, ammonia and amines having a low boiling point (boiling point of 150 ° C. or less) or azeotropes with water evaporate from the moisture-proof film during drying. Is preferable because the As the alkali-soluble olefin / unsaturated carboxylic acid copolymer as described above, commercially available products can be used. Co., Ltd.).

The plate-like pigments which can be suitably used in the moisture-proof layer of the present invention include, firstly, phyllosilicate minerals. Those belonging to phyllosilicate minerals have a plate-like or flaky shape and have a clear cleavage, and are composed of mica, pyrophyllite, talc, chlorite, septe chlorite, serpentine, stilp-nomelane, and clay. There are minerals. Among these, minerals which are large in production and large in production, such as mica and talc, are preferred. Mica includes muscovite (muscovite), sericite (sericite), biotite (flokopite), biotite (biotite), fluorophlogopite (artificial mica, synthetic mica), red mica, soda mica, and vanadin mica , Illite, chimica, paragonite, brittle mica, potassium tetrasilicic mica, sodium tetrasilicic mica,
Examples thereof include sodium teniolite and lithium teniolite. Synthetic products such as synthetic mica that are similar in composition to talc are also included in the scope of the present invention. Clay minerals such as kaolin are also generally referred to as flat crystals. However, if one crystal is taken, there is a plate-like portion but the whole is granular. However, among the kaolins, delamikaolin or the like, in which the crystal layer is intentionally peeled off and made flat, can be used as the flat pigment in the present invention. Further, it is preferable to use a particle diameter of the tabular pigment corresponding to the thickness of the moisture-proof layer. In this case, the flat pigment is pulverized and classified by a pulverizer such as a ball mill, a sand grinder, a cobol mill, and a jet mill to obtain a desired particle diameter, and then used in the present invention.

The tabular pigments suitably used in the present invention
2. Smectites, vermiculites, etc.
High swelling clay minerals can be mentioned. More specifically
Is dickite, nacrite, smectite, halloy
Site, antigolite, chrysotile, pyrophylla
Site, tetrasilyl mica, sodium teniorai
G, margarite, vermiculite, zansofirai
And chlorite. Especially smecties
Montmorillonite, smectite
Iderite, Nontronite, Saponite, Iron Saponai
G, hectorite, sauconite, stevensite, etc.
Can be mentioned. As synthetic smectite, the formula
(Na and / or Li)_0.1~_1.0Mg_2.4~
_2.9Li_{0 . 0}~_0.6Si_3.5~_4.0O_9.0
~_10.6(OH and / or F)_1.5~ _2.5Indicated by
Swelling fluorine mica
JP-A-5-270815, JP-A-7-187
It is synthesized by the method described in JP-A-657-657. Clay ore
The commercial product is generally called sodium benite.
Natural bentonite, commercially available kunipia,
Kuton (Kunimine Industries), Vegum (Vanderbilt)
, Laponite (Laporte), DM Clean A,
DMA-350, Na-Ts (manufactured by Topy Industries), Benge
(Manufactured by Toyshun Yoko Co., Ltd.).
Can be used alone or as a mixture of two or more
You.

In the present invention, the highly swellable clay mineral is defined as a swelling power (standard test method JB by the Bentonite Industry Association of Japan).
AS-104-77).
2 g or more of clay minerals. Specific examples thereof include the above-mentioned 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 (trade name: manufactured by Corp Chemical Co., swelling power: 20 ml / 2 g or more) and Wengel (swelling power: 38 ml / 2 g or more) and so on.

The swelling power of a highly swellable clay mineral is closely related to its ion exchange equivalent. If the ion exchange equivalent is small, the swelling power is small, which is not preferable for use in the present invention. The swellable clay mineral preferably used in the present invention has an ion exchange equivalent of at least 10 milliequivalents per 100 g, more preferably 50 to 300 milliequivalents, and particularly preferably 60 to 300 milliequivalents.
Those having 300 meq or more are included. On the other hand, if the ion exchange equivalent is more than 300 milliequivalents, gelation tends to occur when the solution is converted into an aqueous solution, and the handling becomes difficult. The ion exchange equivalent referred to herein is determined by the amount of adsorbed methylene blue. In general, natural and synthetic scumites are particularly preferred for the present invention because they have an ion exchange equivalent of 85-130 meq / 100 g. Further, as the swellable clay mineral, those having an aspect ratio (Z) of 50 to 5000 are preferable,
The aspect ratio (Z) is represented by the following relationship: Z = L / a [L is the length of clay mineral dispersed in layers in the moisture-proof layer, a is the unit thickness, and Determined by microphotographs]. Further, the swelling clay mineral (swelling force: 20 ml / 2 g or more) and a non-swelling clay mineral such as mica (swelling force: less than 20 ml / 2 g) may be used in combination. Although there is no particular limitation on the mixing ratio, the swelling clay mineral / non-swelling clay mineral 1/99 to 99/1
(Solid content) is preferable. When the proportion of the swelling clay mineral increases, the disintegration improves, but the moisture resistance at ultra-high humidity tends to decrease slightly. Although it improves, the disintegration tends to decrease slightly.

The 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 layer compound include graphite, phosphoric acid salt derivative type compounds (zirconium phosphate compound), chalcogen compound [dichalcogen compound represented by the formula MX ₂ is illustrated. Here, M is a group IV (Ti, Zr, Hf), V
X represents an element belonging to Group (V, Nb, Ta) or Group VI (Mo, W), and X represents a chalcogen (S, Se, Te). ].

The tabular pigment used in the present invention is water,
Alternatively, when the average particle size in a state of being dispersed in a solvent is 20
Those having a diameter between nm and 100 μm are suitable, preferably 0.1 μm to 50 μm, more preferably 1 μm to 3 μm.
0 μm. When the average particle diameter is less than 20 nm, the aspect ratio becomes small, and the effect of improving the moisture resistance is small. On the other hand, if it exceeds 100 μm, the pigment protrudes from the coating layer surface,
It is not preferable because it causes poor appearance and reduced moisture resistance. The average particle diameter of the tabular pigment used in the present invention dispersed in water or a solvent is an average particle diameter of 0.1 μm or more is a value measured by a laser diffraction particle size distribution measuring apparatus to which light scattering theory is applied. . In the case where the average particle diameter dispersed in water or a solvent is 0.1 μm, it is a value measured using a dynamic light scattering method.

The preferred aspect ratio of the tabular pigment used in the present invention is 5 or more, particularly preferably 10 or more. When the aspect ratio is less than 5, the moisture-proof property is reduced because the curved path effect is small. The higher the aspect ratio, the greater the number of layers in the coating layer of the tabular pigment, thereby exhibiting high moisture-proof performance. The thickness of the tabular pigment is measured from a cross-sectional photograph of the moisture-proof film. The thickness is 0.
Those having a size of 1 μm or more are determined by analyzing images from electron micrographs. Those having a thickness of less than 0.1 μm are determined by image analysis from a transmission electron micrograph. The aspect ratio in the present invention is obtained by dividing the average particle diameter dispersed in water or a solvent by the thickness obtained from a cross-sectional photograph of the moisture-proof film. The mixing amount of the synthetic resin and the flat pigment in the moisture-proof layer is preferably from 99/1 to 30/70, more preferably from 90/10 to 35/65, particularly preferably from 85/15 to 70/70 in terms of mass.
40/60. When the blending amount of the tabular pigment is less than 1%, the effect of improving the moisture-proof property and the effect of improving the disaggregation property are reduced. If the tabular pigment exceeds 70%, the resin filling the gap between the tabular pigments becomes insufficient, resulting in an increase in voids and pinholes, resulting in deterioration in moisture resistance.

The moisture proofing agent reacts with a functional group or the like contained in the synthetic resin to modify it to be hydrophobic, or to crosslink it to make it hydrophobic, or by coating a plate-like pigment. Hydrophobizing, or hydrophobizing tabular pigments,
One that promotes the lamination orientation parallel to each other, or one that enhances the adhesion with a synthetic resin and / or a plate-like pigment,
Alternatively, it improves the moisture-proof property of the moisture-proof layer, such as one that fills these gaps.

Examples of the moisture-proofing agent used in the present invention include a urea-formaldehyde condensation reaction product, a melamine-formaldehyde condensation reaction product, and a compound having 1 to 1 carbon atoms.
Eight aldehyde compounds, epoxy compounds having one or more epoxy groups, crosslinking reactive polyvalent metal compounds, organoalkoxysilane compounds, organoalkoxy metal compounds, organic amine compounds, polyamide compounds, polyamide polyurea compounds, polyamine polyureas Compound, polyamidoamine polyurea compound, polyamidoamine compound,
Selected from polyamidoamine-epihalohydrin or formaldehyde condensation reaction product, polyamidepolyurea-epihalohydrin or formaldehyde condensation reaction product, polyaminepolyurea-epihalohydrin or formaldehyde condensation reaction product, and polyamidoamine polyurea-epihalohydrin or formaldehyde condensation reaction product It is preferable to include at least one of them.

Among the compounds used for the moisture-proofing agent, 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 compound. Reacts with the carboxylic acid copolymer, and in particular, hydrogen bonds or dehydrates with the carboxylic acid group to crosslink the polymer or copolymer molecule and render it hydrophobic and water insoluble (three-dimensional network structure) can do. In addition, 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. Thus, the moisture-proof performance of the moisture-proof layer can be enhanced.

The aldehyde compound having 1 to 8 carbon atoms used for the moisture-proofing agent is formaldehyde,
Acetaldehyde, glyoxal, propylaldehyde, propanedial, hexanedial, etc., which are added at their aldehyde groups with the hydrophilic functional groups of the polymer or copolymer contained in the synthetic resin component (a). It can be reacted to render it 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, a polyamide-epoxy resin, etc. A ring-opening addition reaction with the carboxylic acid contained in the acid copolymer can be made hydrophobic and water-insoluble.
Further, the epoxy compound, during the drying of the moisture-proof layer by heating, α
-The olefin / unsaturated carboxylic acid copolymer and the tabular pigment are firmly bound, and these gaps are filled to improve the moisture-proof effect of the moisture-proof layer.

In the present invention, the crosslinking reactive polyvalent metal compound used as a moisture-proofing agent includes, for example, ammonium zirconium carbonate, zirconium alkoxide, titanium alkoxide and aluminum alkoxide. The metal is coordinated or covalently bonded to 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-proofing agent are generally referred to as a coupling agent. The component and the organic component are chemically cross-linked, or chemically or physically bonded to at least one of the two, to increase the affinity of the two, and thereby, the inorganic-
The purpose is to improve the heat resistance, water resistance, mechanical strength, and the like of the organic composite material. In the present invention, the organoalkoxysilane compound and the organoalkoxy metal compound improve the affinity between the α-olefin / unsaturated carboxylic acid copolymer and the tabular pigment, improve the adhesiveness, and adhere the two to form a gap. , Thereby improving the moisture-proof performance of the moisture-proof layer.

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

The organoalkoxy metal compound used in the present invention contains a polyvalent metal atom (for example, Ti, Al, etc.) in the hydrophilic portion thereof. Titanate compounds such as iltitanol, isopropylisostearoyldiacryl titanate, isopropyltricumylphenyltitanate, and isopropyltri (N-amidoethylaminoethyl) titanate, and aluminum compounds such as acetoalkoxyaluminum diisopropylate are included.

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

It is said that the reaction between the hydrophilic group of the coupling agent and the inorganic compound proceeds in the following order. That is, (1) formation of a hydrophilic group formed by hydrolysis of an alkoxy group in the coupling agent, (2) oligomerization of the hydrophilic group of the coupling agent by dehydration condensation, and (3) hydrophilic group or adsorbed water on the inorganic surface. And (4) formation of a covalent bond between the hydrophilic group of the coupling agent and the hydrophilic group on the inorganic surface by the thermal dehydration reaction. As the alkoxy group to be hydrolyzed, a methoxy group,
An ethoxy group, an isopropoxy group, an octyloxy group and the like are used. The reactivity of the hydrophilic compound 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, it shows high reactivity.

On the other hand, as for the hydrophobic group of the coupling agent, when the hydrophobic group is an organic oligomer, a high molecular organic film is formed on the surface of the inorganic compound, the surface is completely hydrophobized, and the synthetic resin matrix is formed. Enhance the adhesion of When the hydrophobic group has a reactive organic functional group such as an epoxy group, a vinyl group, and an amino group, this functional group and α
-Crosslinked with an olefin / unsaturated carboxylic acid copolymer,
Adhesion to α-olefin / unsaturated carboxylic acid copolymer increases. 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-proofing agent in the present invention comprises a coating liquid comprising an α-olefin / unsaturated carboxylic acid copolymer and a plate-like pigment,
It may be formed by mixing a coupling agent, applying the obtained coating liquid to the surface of a paper support, and drying. Alternatively, the surface of the flat pigment is treated in advance with a coupling agent,
It may be fixed to this surface. That is, as a method of using the coupling agent, an integral blend method and a pretreatment method are known. The integral blend method is called α
-A method in which a coupling agent is directly added to a coating liquid containing an olefin / unsaturated carboxylic acid copolymer and a tabular pigment. The pretreatment method is a method of treating a plate-like pigment with a coupling agent in advance, and includes a dry method and a wet method. The dry method is a method in which a powdery plate-like pigment is put into a mixer, which is preheated, a coupling agent is added thereto, and the mixture is stirred at high speed under heating. Is a method in which a coupling agent and a flat pigment are added to the mixture, and the mixture is stirred at a high speed and then dried to obtain a powder. Although the use of the coupling agent is somewhat inferior to the pretreatment method in the integral blend method, the workability is excellent because there is no pretreatment step.

In the case of treating the tabular pigment in an aqueous treatment system in the integral blending method or the wet pretreatment method, a methoxy group or an ethoxy group having a relatively low 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. When the coupling agent is hardly soluble in water, a very small amount of a surfactant may be used in combination.

The amount of the coupling agent to be added is as follows.
The amount is preferably from 0.1 to 5 parts by weight, more preferably from 0.5 to 2 parts by weight, per 100 parts by weight. When the amount of the coupling agent used is less than 0.1 part by weight, the effect of the coating may not be sufficient because the surface of the flat pigment is insufficiently coated with the coupling agent. If it exceeds, the effect of the coupling agent is saturated, which may be uneconomical.

The hydrophobicity of the surface of the tabular pigment treated with the coupling agent becomes excessively high. Therefore, when the aqueous dispersion is used, it becomes thick and cannot be applied, or the dispersion becomes poor and the aggregates are formed. May occur. In this case, the dispersion can be carried out using a surfactant, a polyacrylic acid-based dispersant, or a wetting agent such as isopropyl alcohol and sodium dialkyl sulfosuccinate.

In the present invention, the organic amine compound and the polyamide compound used as the moisture-proofing agent have a cationic property. 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 an organic monoamine, an organic polyamine, or an organic quaternary ammonium salt to give the α-olefin / unsaturated carboxylic acid copolymer a hydrophobicity, Alternatively, water insolubility can be increased.

In the present invention, the organic amine compound used as the moisture-proofing agent may be any of a primary amine compound, a secondary amine compound, a tertiary amine compound, and a quaternary ammonium salt compound. Alternatively, any of an organic monoamine and an organic polyamine may be used.
Further, the organic amine compound has a different functional 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. Examples of such a modified organic amine compound include an adduct of a compound having an epoxy group such as a monoepoxy compound or a diepoxy compound and an amine compound, an adduct of a compound having a hydroxyl group such as ethylene oxide or propylene oxide and an amine compound, and acrylic. Examples include a Michael adduct of a nitrile and an amine compound, and an adduct obtained by a Mannich reaction of a phenol compound, an aldehyde compound, and an amine compound.

The above modifications include 1) reducing the irritating odor and skin irritation of the amine compound, 2) reducing the viscosity of the amine compound, and 3) increasing the molecular weight and weighing. 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, diaminodiphenylsulfone, 4,4 '-(o-toluidine), o-phenylenediamine, methylenebis (o-chloroaniline), m-amino Benzylamine, aniline and the like. 3) Aliphatic polyamine having an aromatic ring group or monoamine metaxylylenediamine, tetrachloroxylylenediamine, trimethylaminomethylphenol, benzyldimethylamine, α-methylbenzyldimethylamine and the like. 4) secondary amine N-methylpiperazine, piperidine,
Hydroxyethylpiperazine, pyrrolidine, morpholine and the like. 5) Tertiary amine tetramethylguanidine, triethanolamine, N, N'-dimethylpiperazine, N-methylmorpholine, hexamethylenetetramine, triethylenediamine, 1-hydroxyethyl-2-heptadecylglyoxalidine, pyridine, pyrazine , Quinoline and the like. 6) Quaternary ammonium salts diallyldimethylammonium chloride, hexyltrimethylammonium chloride, cyclohexyltrimethylammonium chloride, octyltrimethylammonium bromide, 2-
Ethylhexyltrimethylammonium bromide,
1,3-bis (trimethylammoniomethyl) cyclohexane dichloride, lauryldimethylbenzylammonium chloride, stearyldimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium chloride and the like. 7) Betaine compounds, glycine compounds, amino acid compounds coconut oil alkyl betaine, lauryl dimethylaminoacetic acid betaine, amidopropyl betaine laurate, 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, and a modified polyamine.

The polyamide compound (also referred to as a polyamidoamine compound) used in the present invention is obtained by a dehydration condensation reaction between the above amine compound and a compound having a carboxylic acid group. For example, a reaction product of tall oil with diethyltriamine, a reaction product of a dimer of linolenic acid with tetraethylpentamine, a reaction product of triethylenetetramine with a saturated dibasic acid (adipic acid, sebacic acid, isophthalic acid, terephthalic acid) Products, reaction products of a polymerized fatty acid and diethyltriamine, and the like. The molecular weight of these polyamide compounds is preferably about 1,000 to 5,000.

The organic amine compound or polyamide compound used in the present invention is preferably water-soluble, but even if it is insoluble in water, it can be used after emulsification or dispersion treatment. Two or more of the above amine compounds or polyamide compounds may be used as a mixture. The amine value of the organic amine compound or the polyamide compound is generally preferably from 100 to 1,000, but is not particularly limited.

In the present invention, the epoxy compound used as the moisture-proofing agent may be a monoepoxy compound. The monoepoxy compound includes an aliphatic monoepoxy compound and an aromatic monoepoxy compound. 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 monoepoxy compound.
It can be used by dispersing it in water by weight%.

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

When a moisture-proofing agent containing the above-mentioned monoepoxy compound is used, the synthetic resin (a) used therewith is a hydrophilic functional group (carboxylate) capable of reacting with an epoxy ring such as acrylic acid or acrylamide. Group, an amide group, and a hydroxyl group, etc.).

In the present invention, the polyamide polyurea compound, polyamine polyurea compound, polyamidoamine polyurea compound and polyamidoamine compound used as a moisture-proofing agent are (i) polyalkylene polyamine or alkylene polyamine, (ii) urea , (Iii) a dibasic carboxylic acid, and optionally (iv) aldehydes,
It is obtained by reacting a compound selected from epihalohydrins and α, γ-dihalo-β-hydrins (Japanese Patent Publication No.
9-32597, JP-A-4-10097, etc.). In the above synthesis, the dibasic carboxylic acid (iii)
Is used, a polyamide polyurea compound or a polyamidoamine polyurea compound is obtained, and when not used, a polyamine polyurea compound is obtained. When an aldehyde or epihalohydrin is used, it is preferable that the amount of the aldehyde or epihalohydrin used is very small, or self-crosslinking occurs during the synthesis process so that almost no free methylol group or epoxy group remains. In the above reaction, a polyalkylene polyamine or an alkylene polyamine (i) is reacted with a dibasic carboxylic acid without using the urea number (ii) to obtain a polyamidoamine compound. Component (iv) Aldehydes, epihalohydrins, and α, γ-dihalo-β-
The reaction amount of the hydrins is preferably in the range of 5 to 300 mol per 100 mol of the component (i).

The polyalkylene polyamine or alkylene polyamine used as component (i) includes
For example, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, iminobispropylamine, 3-azahexane-1,6-diamine, 4,7-
Examples include diazadecane-1,10-diamine, ethylenediamine, propyldiamine, 1,3-propanediamine, hexamethylenediamine, and the like. Among them, it is preferable to use diethylenetriamine and / or triethylenetetramine. These compounds (i) are used alone or as a mixture of two or more. In addition, one or more of an alicyclic amine such as cyclohexylamine and an alicyclic epoxy compound may be used in combination with the compound (i).

The ureas used as component (ii) include urea, thiourea, guanylurea, methylurea, dimethylurea and the like. Among these, it is preferable to use urea. These urea compounds may be used alone or as a mixture of two or more.
The dibasic carboxylic acids used as the component (iii) have a carboxyl group or two groups derived therefrom in the molecule and may be a free acid, or may be an ester or an acid anhydride. It may be a thing. The dibasic carboxylic acid may be any of aliphatic, aromatic and alicyclic dibasic carboxylic acids. Specific examples thereof include succinic acid, glutaric acid, adipic acid, sebacic acid,
Maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid and the like can be mentioned. Further, polyesters which are a reaction product of a dibasic carboxylic acid and a glycol and have a free carboxylic acid group at a terminal may be used. These dibasic carboxylic acids may be used alone or as a mixture of two or more. Aldehydes used as the component (iv) include alkyl aldehydes such as formaldehyde and propyl aldehyde, and glyoxal, propane dial, butane dial, and epihalohydrins include epichlorohydrin and epibromohydrin. Further, examples of the α, γ-dihalo-β-hydrin used as the component (iv) include 1,3-dichloro-2-propanol.

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

Further, as a monomer component, an alicyclic epoxy compound, an alkylating agent (general formula RX; R = lower alkyl group, alkenyl group, benzyl group, phenoxyethyl group, etc., X = halogen atom), 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 an arbitrary order, and the following method can be used as an example of the synthesis method. That is, an alkylene diamine or polyalkylene polyamine is subjected to a deammonification reaction with a urea, and then the reaction product is dehydrated and condensed with a dibasic carboxylic acid, followed by a deammonification reaction with the urea to obtain a polyamide polyurea. A compound is obtained. When the polyamide polyurea compound is reacted with a compound selected from aldehydes, epihalohydrins and α, γ-dihalo-β-hydrins, a polyamide polyurea-aldehyde (epihalohydrin) resin is obtained.

Aldehydes, epihalohydrins, α,
The γ-dihalo-β-hydrins are used for the purpose of adjusting the molecular weight and 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 above-mentioned polyamide polyurea compound, polyamine polyurea compound, polyamidoamine polyurea compound and polyamidoamine compound which are used as a moisture-proofing agent show a slight cationic property in an aqueous coating solution. It is presumed that the tabular pigment having the property is softly agglomerated during the film forming process, and at this time, these tabular particles are stacked and oriented parallel to each other. Such an improvement in the stacking orientation of the tabular grains improves the moisture-proof performance of the moisture-proof 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. / / Most of the methylol group-forming compound is self-crosslinking,
The effect of these functional groups is negligible. Therefore, the moisture-proof layer containing the above compound as a moisture-proof property improver easily disintegrates from the paper support when the moisture-proof paper is recovered and regenerated, and hardly impairs the disintegration property of the recycled pulp.

In the present invention, the moisture-proofing agent is preferably used in a proportion of 0.05 to 30 parts by weight based on 100 parts by weight of the total of the synthetic resin and the tabular pigment in terms of mass. It is more preferably 0.5 to 20 parts by weight, particularly preferably 1 to 10 parts by weight. When the amount is less than 0.05 part by weight, the effect of improving the moisture-proof property may be insufficient, and when it exceeds 30 parts by weight, the effect of improving the moisture-proof property is saturated, and economically It can be disadvantageous. Further, a moisture-proofing agent composed of two or more compounds may be used.

In the moisture-proofing agent used in the moisture-proofing paper of the present invention, a crosslinking agent and a coupling agent may be used in combination. In this case, the crosslinking reagent 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 at least one epoxy group,
It may include one or more selected from a crosslinking reactive polyvalent metal compound and an organic amine compound, a polyamide compound, and the like, and the coupling agent is selected from the aforementioned organoalkoxysilane compounds and organoalkoxy metal compounds. One or more may be included. Further, the amount of carboxylic acid contained in the α-olefin / unsaturated carboxylic acid copolymer is more preferably at least 5 mol% in terms of acid modification.

In the present invention, the amount of alkali metal ions in the moisture-proof layer is preferably 0.01% by weight to 1% by weight based on the solid content of the moisture-proof layer. The amount of alkali metal ions in the moisture-proof layer is 0.
When the content is less than 01% by weight, the effect of improving the moisture-proof property reaches a plateau. When the amount of alkali metal ions exceeds 1% by weight, the moisture resistance deteriorates. The amount of alkali metal ions in the moisture-proof layer is derived not only from the components constituting the moisture-proof layer but also from the amount of alkali metal ions eluted from the anchor layer when the moisture-proof layer is formed. Therefore, the total amount of alkali metal ions in the moisture-proof layer is the sum of the amount of alkali metal ions in the moisture-proof layer itself and the amount of alkali metal ions eluted from the anchor layer. The amount of alkali metal ions eluted from the anchor layer is not only the amount of alkali metal ions contained in the anchor layer, but also the water resistance of the anchor layer itself, and the concentration and concentration of the drying method and coating method or moisture-proof paint when forming the moisture-proof layer. Affected by viscosity. However, as long as the amount of alkali metal ions in the anchor layer is within the range of the present invention, the desired moisture resistance can be achieved irrespective of other conditions. Of course, if the anchor layer is low in water resistance enough to dissolve at the moment of getting wet with water, not only can the desired moisture proof property not be achieved, but also the moisture proof layer will gel during coating, The structure is greatly changed, which is not preferable.

In the present invention, an overcoat layer can be further provided on the moisture-proof layer. The overcoat layer in the present invention improves the moisture-proof property by filling the pinholes of the moisture-proof layer or filling minute voids. Therefore, there is no particular limitation as long as it is an overcoat layer containing a resin having good film-forming properties and good water resistance. Examples of resins used include styrene-butadiene-based copolymer synthetic resin, methacrylate-butadiene-based copolymer synthetic resin, acryl-styrene-based copolymer synthetic resin, acrylic ester-based synthetic resin, and polyester-based synthetic resin. , Acrylonitrile-based synthetic resin, polyvinyl alcohol-based synthetic resin, ethylene-vinyl alcohol-based synthetic resin, vinyl acetate-based synthetic resin, ethylene-vinyl acetate copolymer-based synthetic resin, vinyl chloride-based resin, vinylidene chloride-based resin, starch-based natural resin , Cellulose-based natural resin, urethane-based resin, polyamide-based resin, olefin-based resin,
There is no particular limitation as long as the resin has a film-forming ability, such as an olefin / unsaturated carboxylic acid copolymer-based resin and a styrene-based resin. The overcoat layer may contain an inorganic pigment or an organic pigment for preventing blocking or the like. Overcoat amount is 0.1 ~
20 g / m ² is preferred. If necessary for the paint for anchor coat, moisture-proof paint and paint for overcoat of the present invention, a dispersant such as polycarboxylic acid, a defoamer such as silicone, a surfactant, a water retention agent, a color adjusting agent, etc. Can be added.

The above-described paint is applied to a paper support to form an anchor layer, a moisture-proof layer, and an overcoat layer. The coating equipment is not particularly limited, but a system such as a blade coater, a bar coater, an air knife coater, and a slit die coater is preferable. In particular, when forming an anchor layer, a coater that scrapes the coating surface such as a blade coater, bar coater, air knife coater, slit die coater, etc. It is preferable in that it prompts.

The substrate used in the present invention is not particularly limited as long as it contains pulp which is easily dispersed in water by mechanical disaggregation as a main component, but is generally used bleached or unbleached. Kraft paper (acid paper or neutral paper), or paperboard used for corrugated cardboard, building materials, white balls, chip balls, and the like are suitable, and more preferably forced drying with a yanke dryer or the like. A piece of glossy paper,
Or a bleached / unbleached kraft paper which has been subjected to a calendar treatment. When such a paper base material is used, the flat pigment in the thickness direction of the moisture-proof layer is formed from the highly smooth base material surface. The orientation is easy to arrange uniformly and in parallel without being disturbed with respect to the coating surface, so that the moisture-proof performance is also remarkably improved.

[0083]

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, parts in the examples are parts by mass.

<Anchor paint 1> 100 parts of clay (trade name: Amazon, manufactured by CADAM, specific gravity 2.6, average particle size 3.3 μm) was added to 100 parts of water, and the mixture was mixed with carboxylic acid-modified SBR latex ( 28.6 parts (trade name: S1X2, manufactured by Zeon Corporation, acid modification ratio: about 20%, Tg: 18 ° C., solid content concentration: 50%) were mixed and stirred to obtain anchor paint 1. (Quantitative determination of the amount of alkali metal ions) Anchor paint 1 was applied on a glass plate with a Mayer bar and dried at 120 ° C. for 1 minute to obtain a coated film. After the glass plate was cooled to room temperature, the coating film was shaved with a razor and quantified by an ion chromatography method. The amount of alkali metal ions in the anchor coating material 1 was 0.05% by weight.

<Anchor Coating 2> 100 parts of clay (trade name: Amazon, manufactured by CADAM, specific gravity 2.6, average particle diameter 3.3 μm) was added to 100 parts, and the mixture was mixed with carboxylic acid-modified SBR latex ( Trade name: S1X2, manufactured by Zeon Corporation, 30 parts of an acid modification ratio of about 20%, Tg of 18 ° C., solid content concentration of 50%) and 1 part of a 10% aqueous solution of caustic soda were mixed and stirred to obtain an anchor paint 2. As a result of quantifying the amount of alkali metal ions in the same manner as in the anchor paint 1, the amount of alkali metal ions in the anchor paint 2 was 0.1%.
% By weight.

<Anchor paint 3> 100 parts of clay (trade name: Amazon, manufactured by CADAM, specific gravity 2.6, average particle diameter 3.3 μm) was added to 100 parts of water, and the mixture was mixed with an aqueous solution of ethylene acrylic acid copolymer. (Product name: Siixen-
N, manufactured by Sumitomo Seika, molecular weight: 25,000, acrylic acid / ethylene copolymerization ratio = 15/85, solid content: 25%, caustic soda neutralization type) 1 part, and 10% caustic soda aqueous solution
Five parts were mixed and stirred to obtain anchor paint 3. As a result of quantifying the amount of alkali metal ions in the same manner as in the case of anchor paint 1, the amount of alkali metal ions in anchor paint 3 was 0.2% by weight.

<Anchor Coating Material 4> 100 parts of clay (trade name: manufactured by Amazon, manufactured by CADAM, specific gravity: 2.6, average particle diameter: 3.3 μm) was added to 100 parts of water, and the mixture was mixed with carboxylic acid-modified SBR latex ( Trade name: 30 parts of S1X2, manufactured by Nippon Zeon Co., Ltd., acid modification ratio: about 20%, Tg: 18 ° C., solid content concentration: 50%), and 20 parts of a 10% aqueous solution of caustic soda were mixed and stirred to obtain anchor coating material 4. As a result of quantifying the amount of alkali metal ions in the same manner as in the case of anchor paint 1, the amount of alkali metal ions in anchor paint 4 was 1.0%.
% By weight.

<Anchor Paint 5> 100 parts of clay (trade name: Amazon, manufactured by CADAM, specific gravity 2.6, average particle diameter 3.3 μm) was added to 100 parts of water, and the mixture was mixed with carboxylic acid-modified SBR latex. (Product name: S1X2,
Nippon Zeon, acid modification rate about 20%, Tg 18 ° C, solid content concentration 50%) 20 parts, and caustic soda 10% aqueous solution 60
The parts were mixed and stirred to obtain an anchor paint 5. As a result of quantifying the amount of alkali metal ions by the same method as that for the anchor paint 1, the amount of alkali metal ions in the anchor paint 5 was 3.
It was 0% by weight.

<Coating for Anchor 6> 100 parts of clay (trade name: Amazon, manufactured by CADAM, specific gravity 2.6, average particle diameter 3.3 μm) was added to 100 parts of water, and the mixture was mixed with carboxylic acid-modified SBR latex ( Trade name: 30 parts of S1X2, manufactured by Zeon Corporation, acid modification rate: about 20%, Tg: 18 ° C., solid content concentration: 50%, and 10% aqueous solution of caustic soda 159
The parts were mixed and stirred to obtain an anchor paint 6. As a result of quantifying the amount of alkali metal ions by the same method as that for anchor paint 1, the amount of alkali metal ions in anchor paint 6 was 7.
It was 0% by weight.

<Moisture-proof paint 1> Montmorillonite (trade name: Knipia F, manufactured by Kunimine Industries, particle size: 520 nm)
Was dispersed in ion-exchanged water (0.7 μs / cm or less) at a solid content of 5%, and 66.7 parts of an aqueous solution of ethylene acrylic acid copolymer (trade name: Seixen-AC, manufactured by Sumitomo Seika; molecular weight: 25,000) , Acrylic acid / ethylene copolymerization ratio = 15/85, solid content 30%, ammonia neutralized type) 100 parts and stirred to prepare a moisture-proof paint 1 (a flat pigment and an α-olefin / unsaturated carboxylic acid copolymer). Combined ratio = 10/90). As a result of quantifying the amount of alkali metal ions by the same method as that for anchor paint 1, the amount of alkali metal ions in moisture-proof paint 1 was 0.3% by weight.

<Moisture-Proof Paint 2> 100 parts of water contains natural mica (Mica, trade name: FA-500, manufactured by Mica Yamaguchi Corporation).
Composition formula _{K 2 O · 3Al 2 O 3} · 6SiO 2 · 2H 2 O,
100 parts of an average particle diameter of 18 μm and an aspect ratio of 20) were added, and a carboxylic acid-modified SBR latex (trade name: S1X2, manufactured by Zeon Corporation, acid modification rate: about 20%, Tg)
300 parts (18 ° C., solid content concentration: 50%) were added and stirred to prepare a moisture-proof paint 2 with a plate-like pigment and a carboxylic acid-modified SB.
R latex compounding ratio = 40/60). As a result of quantifying the amount of alkali metal ions by the same method as that for anchor paint 1, the amount of alkali metal ions in moisture-proof paint 2 was 0.2% by weight.
Met.

Example 1 Anchor paint 1 was applied to one side of unbleached kraft paper (70 g / m ² , thickness 100 μm) with a Mayer bar so as to have a coating amount of 10 g / m ² as a solid content. Thereafter, drying was performed at 120 ° C. for 1 minute to form an anchor layer. The moisture-proof paint 1 was applied on the anchor layer with a Mayer bar so that the coating amount was 5 g / m ² as a solid content, followed by drying at 130 ° C. for 2 minutes to obtain a moisture-proof laminate.

Example 2 Anchor paint 2 was applied to one surface of unbleached kraft paper (70 g / m ² , thickness 100 μm) with a Mayer bar so as to have a coating amount of 10 g / m ² as a solid content. Thereafter, drying was performed at 120 ° C. for 1 minute to form an anchor layer. The moisture-proof paint 1 was applied on the anchor layer with a Mayer bar so that the coating amount was 5 g / m ² as a solid content, followed by drying at 130 ° C. for 2 minutes to obtain a moisture-proof laminate.

Example 3 Anchor paint 3 was applied to one surface of unbleached kraft paper (70 g / m ² , thickness 100 μm) with a Mayer bar so as to have a coating amount of 10 g / m ² as a solid content. Thereafter, drying was performed at 120 ° C. for 1 minute to form an anchor layer. The moisture-proof paint 2 was applied on the anchor layer with a Mayer bar so that the coating amount was 5 g / m ² as a solid content, followed by drying at 130 ° C. for 2 minutes to obtain a moisture-proof laminate.

Example 4 Anchor coating material 4 was applied to one surface of unbleached kraft paper (70 g / m ² , thickness 100 μm) with a Mayer bar so as to have a coating amount of 10 g / m ² as a solid content. Thereafter, drying was performed at 120 ° C. for 1 minute to form an anchor layer. The moisture-proof paint 2 was applied on the anchor layer with a Mayer bar so that the coating amount was 5 g / m ² as a solid content, followed by drying at 130 ° C. for 2 minutes to obtain a moisture-proof laminate.

Example 5 Anchor coating material 5 was applied to one surface of unbleached kraft paper (70 g / m ² , thickness 100 μm) with a Mayer bar so as to have a coating amount of 10 g / m ² as a solid content. Thereafter, drying was performed at 120 ° C. for 1 minute to form an anchor layer. The moisture-proof paint 2 was applied on the anchor layer with a Mayer bar so that the coating amount was 5 g / m ² as a solid content, followed by drying at 130 ° C. for 2 minutes to obtain a moisture-proof laminate.

<Comparative Example 1> Anchor paint 6 was applied to one surface of unbleached kraft paper (70 g / m ² , thickness 100 μm) with a Mayer bar so as to have a coating amount of 10 g / m ² as a solid content. Thereafter, drying was performed at 120 ° C. for 1 minute to form an anchor layer. The moisture-proof paint 1 was applied on the anchor layer with a Mayer bar so that the coating amount was 5 g / m ² as a solid content, followed by drying at 130 ° C. for 2 minutes to obtain a moisture-proof laminate.

<Comparative Example 2> The moisture-proof paint 1 was applied to one surface of unbleached kraft paper (70 g / m ² , thickness 100 μm) as a solid content with a Mayer bar so as to have a coating amount of 5 g / m ^2. And dried at 120 ° C. for 1 minute to obtain a moisture-proof laminate.

[0099]

[Table 1]

<Test Method> 1) Quantification of the amount of alkali metal ions in the moisture-proof layer and the anchor layer The surface of the moisture-proof layer of the moisture-proof laminate is cut out with a razor blade until the moisture-proof layer disappears. The interface between the moisture-proof layer and the anchor layer is estimated from the coating amount or the moisture-proof layer thickness of the moisture-proof layer and the weight of the moisture-proof layer removed. The sense (sharpness and hardness) when shaving with a razor blade and the state of the shaved powder differ between the moisture-proof layer and the anchor layer. The sample immediately before reaching the anchor layer is used as a sample of the moisture-proof layer. When the moisture barrier is completely removed and reaches the anchor layer, a sample of the anchor layer is taken.
The sample of the anchor layer does not use a portion cut off from a portion of about half the thickness of the anchor layer and a depth of about 5 μm from the interface, but uses a portion cut off from a portion deeper than that. This is because the alkali metal ions contained in the anchor layer at the portion near the interface between the moisture-proof layer and the anchor layer (within several μm from the interface) have already flowed out into the moisture-proof layer. This is because the amount of the alkali metal ion cannot be determined. The extent to which the anchor layer was removed was confirmed by comparing an electron micrograph of the cross section of the anchor layer and the moisture-proof layer of the moisture-proof laminate that had not been removed, and a cross-sectional photograph after the anchor layer was removed. Each sample of the moisture-proof layer and anchor layer that were cut out was 10
Approximately mg is measured in 0.1 mg units, put into an extraction tube of a Soxhlet extraction apparatus, and a flask containing 100 ml of pure water is connected downward, and a reflux condenser is connected upward. The flask is immersed in an oil bath, and the pure water in the flask is boiled and evaporated to perform 12 hrs extraction. The extract was filtered through a membrane filter, cooled to room temperature, and then accurately measured in volume. The extract is diluted 100-fold with pure water and ion chromatographed (Dionex DX-120).
And the amount of alkali metal ions was determined. In addition, when the sample concentration exceeded the detection limit, it was measured by appropriately diluting. The conditions of the ion chromatograph are as follows. Column: Ion Pac CG3, Ion Pac C
S3 Eluent: 10 mM hydrochloric acid, 0.2 mM diaminopropionic acid Flow rate: 1.0 ml / min Removal solution: 0.04 M tetramethylammonium hydroxide Flow rate: 3 ml / min Column temperature: room temperature Detector: electric conductivity detector (10 μS / cmF. S)
Sample injection volume: 50 μl All the alkali metal ions detected by the above ion chromatograph were sodium ions, and the other alkali metal ions were below the detection limit. In addition, the value quantified by this method was equal to the value quantified by directly shaving the anchor layer formed on the glass plate with the anchor paint on the glass plate.

2) Moisture permeability JIS-Z-0208 (cup method) B method (40 ° C. 90%
(RH) with the moisture-proof coated side facing out. If the moisture permeability is 50 g / m ² · 24 hours or less, the moisture-proof laminate is considered to be practical. The measurement under the ultra-high humidity condition was performed in an environment of 40 ° C. and 100%.
Note that the moisture permeability standard under ultra-high humidity conditions is 100
If g / m 2 ^· 24 hours or less practical is that there as a moisture laminate ultra-high humidity conditions.

3) Disintegration A 45 g equivalent of the moisture-proof laminate was cut into a square of about 5 cm, and the product was cut in 1500 g of water using a TAPPI disintegration standard machine (disintegrator, 2 liter container).
Disintegrated for 0 minutes. A sheet having a basis weight of 60 g / m ² was prepared from the obtained slurry using a laboratory hand-making machine. Undisintegrated material (film piece or paper piece) in the obtained sheet
The size of the undisintegrated pieces present in the sheet was visually evaluated as large, and those having a major axis of 5 mm or less were evaluated as ○, and those having undisintegrated deformation larger than 5 mm were evaluated as x. If the size of the undisintegrated pieces is 5 mm or less, it can be used as ordinary waste paper.

[0103]

Industrial Applicability According to the present invention, a moisture-proof paper (having water disintegration properties) that can be reused as waste paper, has a remarkably improved moisture-proof property at ultra-high humidity, and has a moisture-proof property even at a low coating amount. It is possible to provide a moisture-proof laminate excellent in defibration properties.

 ──────────────────────────────────────────────────の Continued on the front page F term (reference) 4F100 AC03B AC03C AC04C AC05C AK01C AK70C AK73B AK73C AL07B BA03 BA04 BA07 BA10A BA10C CA13C CC00B CC00C CC00D DE02C DG10A GB15 JD04 JL16 JM01B JM01C

Claims (5)

[Claims] 1. A moisture-proof laminate comprising an anchor layer provided on at least one surface of a paper support and a moisture-proof layer containing a synthetic resin and a flat pigment on the anchor layer, wherein the amount of alkali metal ions in the anchor layer is an anchor. 0 to the solid content of the layer.
Moisture-proof laminate characterized in that the content is from 0.01 to 5% by weight. 2. The coating amount of the anchor layer is 0.1 to 20 g / m.
^2, moistureproof laminate according to claim 1, wherein the coating amount of the moisture barrier, characterized in that a 0.1 to 20 g / ^{m 2.} 3. The moisture-proof laminate according to claim 1, wherein the tabular pigment is at least one selected from phyllosilicate minerals and highly swellable clay minerals. 4. The moisture-proof laminate according to claim 1, wherein the amount of alkali metal ions in the moisture-proof layer is 0.01 to 1% by weight based on the solid content of the moisture-proof layer. 5. The moisture-proof laminate according to claim 1, further comprising an overcoat layer on the moisture-proof layer.