JP2001355195A - Moistureproof laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remarkably raise moistureproofness and to obtain a moistureproof laminate excellent in disintegrating properties in the moistureproof laminate reutilizable as a waste paper (having water disintegrating properties). SOLUTION: This moistureproof laminate comprises a moistureproof layer containing the following components in the moistureproof laminate provided with an anchor layer on at least one surface of a support and further the moistureproof layer formed on the anchor layer. (1) a flake pigment, (2) an α-olefin-unsaturated carboxylic acid copolymer and (3) a vinylic emulsion polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture-proof laminate (having water disintegration properties) that can be reused as waste paper. More specifically, the present invention relates to a moisture-proof laminate required for a moisture-proof laminate.
An object of the present invention is to provide a moisture-proof laminate capable of dramatically improving waterproofness as compared with the conventional case.

[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 or polypropylene onto paper, and winding the wrapping paper having moisture resistance and water resistance into a roll shape in the same form or as desired. Cut to size and used. Also, cement bags, salt bags,
For base paper for heavy bags such as feed bags, fertilizer bags, garbage bags, etc., after bag making and bagging, moisture proof and strength are required to transport heavy objects while preventing moisture absorption and water absorption of the contents. A laminate of kraft paper and polyolefin laminate paper (hereinafter referred to as polylaminate paper) obtained by laminating kraft paper with polypropylene or the like is used. 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 polylaminate 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.

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 of obtaining a moisture-proof paper by applying a compound 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. In addition, it is difficult to obtain a moisture-proof property comparable to that of polyethylene-laminated paper by applying it 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 by the moisture-proof wrapping paper is used. When loading, unloading, or transporting rolled paper, a gap may occur between the wrapping paper and its contents,
In severe cases, a serious problem such as tearing of the wrapping paper and the accompanying drop of contents occurs. Further, there is a problem that the label is immediately peeled off even if a label is attached to the surface of the moisture-proof layer containing such a wax. Furthermore, an adhesive which is usually used at the time of packaging causes poor adhesion. Particularly, a vinyl acetate emulsion-based adhesive used for general purposes cannot be applied due to repelling, or even if it can be applied, there is no adhesiveness at all. Therefore, it is necessary to use a very limited adhesive such as a hot-melt adhesive which is 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 also a method of bonding using an adhesive tape.However, when using an adhesive tape, there is a serious disadvantage that the workability at the time of packaging is significantly inferior to bonding with an adhesive, and it is used only for specific applications. It is not possible at present.

[0004] In order to solve these problems,
There has been proposed a moisture-proof paper provided with an anti-slip layer made of an amphoteric compound on the back surface of a support (JP-B-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 long windings due to the occurrence of winding slip at the time of winding, or significant work in the subsequent process due to uneven winding side surfaces. However, there is a problem that the deterioration of the property is accompanied. As described above, at present, there is no moisture-proof paper that has a disintegrating property and contains moisture-proof wax that is superior to plastic film and that does not cause problems due to slippage of packages. . Further, as a moisture-proof paper without using wax, the present inventors have proposed 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 Laid-Open No. 9-2).
No. 1096). In the present invention, a moisture-proof layer is formed by mixing a pigment which is considered to be impervious to water vapor itself, for example, a flat pigment such as a flat pigment with a polymer such as a synthetic resin latex. The moisture-proof mechanism is that the water vapor permeation area is small in a plane, and the plate-like pigments are arranged in parallel in the thickness direction in parallel with 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.

However, the present invention has a moisture permeability of 15 to
It is very effective for producing a moisture-proof paper in the range of 60 g / m ² · 24 hr, but if it is desired to obtain a paper having a moisture permeability of 15 g / m ² · 24 hr or less, especially 10 g / m ² · 24 hr or less, The coating amount of the moisture-proof layer is 100 g / m ^{2 to} 200 g
/ M ² is very difficult to produce industrially. In addition, there is a problem that the value as used paper is reduced because the ratio of the moisture-proof layer in the moisture-proof paper is relatively large. Further, the moisture-proof paper having a moisture-proof layer formed of an alkaline aqueous solution of an α-olefin / unsaturated carboxylic acid copolymer (alkali-soluble resin) or an emulsion of an α-olefin / unsaturated carboxylic acid copolymer has a coating amount of 20-30g
/ M although moisture permeability ² exerts 30 g / m ² · 24 hr or longitudinal, itself, can not be re-defibration for strong film similar to polyethylene film, can not be reused as waste paper.
For this purpose, there is a method of providing a moisture-proof resin layer made of a mixture of an α-olefin / unsaturated carboxylic acid low molecular weight copolymer and a vinyl emulsion polymer on the surface of paper (JP-A-2000-2000).
-80593). Although this method allows the moisture-proof layer to be defibrated, the defibrated pieces are large and still insufficient for use as waste paper. Further, since the melting point of the α-olefin / unsaturated carboxylic acid copolymer is from 100 ° C. to 140 ° C., in the drying step in papermaking, disintegrated pieces are fused to a cylinder dryer, and paper cannot be produced.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a moisture-proof laminate which is reusable as used paper (having water disintegration properties) and has a remarkably enhanced moisture-proof property and excellent disintegration properties. Is what you do.

[0007]

The present invention employs the following method to solve the above-mentioned problems. That is, the first of the present invention is:
A moisture-proof laminate comprising an anchor layer provided on at least one surface of a support and a moisture-proof layer provided on the anchor layer, wherein the moisture-proof layer comprises the following components (1) to (3). (1) Tabular pigments. (2) α-olefin / unsaturated carboxylic acid copolymer. (3) A vinyl emulsion polymer. A second aspect of the present invention is the moisture-proof laminate according to the first aspect, wherein the α-olefin / unsaturated carboxylic acid copolymer is an ethylene / acrylic acid or ethylene / methacrylic acid copolymer and has a molecular weight of 5,000 to 100,000. It is. A third aspect of the present invention is the moisture-proof laminate according to the first or second aspect, wherein the vinyl emulsion polymer has a glass transition point (Tg) of 10 ° C. or more. A fourth aspect of the present invention is:
The moisture-proof laminate according to any one of the first to third inventions, wherein the average particle size of the vinyl emulsion polymer is not more than the average particle size of the tabular pigment. A fifth aspect of the present invention is the moisture-proof laminate according to the first to fourth aspects, wherein the moisture-proof layer contains a moisture-proof property improver. A sixth aspect of the present invention is the moisture-proof laminate according to the first to fifth aspects, wherein the anchor layer contains a pigment and an aqueous adhesive resin. A seventh aspect of the present invention is the moisture-proof laminate according to any one of the first to sixth aspects, having an overcoat layer on the moisture-proof layer.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The present inventors first studied the moisture-proof properties of the α-olefin / unsaturated carboxylic acid copolymer alone film. This film has a coating amount of about 20 g / m ^{2 to} 30 g / m ² and a moisture permeability of 30 to
40 g / m ² · 24 hr, almost the same moisture-proof property as polyethylene-laminated paper. However, this moisture-proof film is very strong, and even if it is attempted to disintegrate in water to be reused as waste paper, the film pieces remain as large films without falling apart. Further, if papermaking is performed while the film pieces are mixed in the pulp, the film pieces are fused to a cylinder dryer in a papermaking drying step, so that paper cannot be produced. It was found that it was very difficult to reuse α-olefin / unsaturated carboxylic acid copolymer alone as waste paper. Thus, a moisture-proof paper was produced by adding a flat pigment such as mica to the α-olefin / unsaturated carboxylic acid copolymer. The moisture-proof film of the moisture-proof paper thus obtained was found to disintegrate in water because the moisture-proof film was broken by mechanical action based on the flat pigment. Also, the inventors have found that a film composed of an α-olefin / unsaturated carboxylic acid copolymer and a plate-like pigment has improved heat resistance and does not fuse to a cylinder due to heat (80 to 180 ° C.) in a drying process in papermaking. Was. Observation of the cross section of the film composed of this α-olefin / unsaturated carboxylic acid copolymer and the plate-like pigment by an electron microscope shows that the plate-like pigment is oriented to the coating surface in the film to some extent, although there is a certain degree of orientation. I knew I was doing it. Since the flat pigment itself is considered to be impervious to water vapor, the water vapor that has entered the membrane must be transmitted so as to bypass the flat pigment (reduction in the transmission coefficient due to the curved effect). Therefore, the permeation distance of water vapor is increased many times, and the moisture proof property is improved. Further, by adding the tabular pigment, the volume fraction of the α-olefin / unsaturated carboxylic acid copolymer occupying in the film is reduced, the amount of water vapor dissolved in the film (dissolution coefficient) is reduced, and the moisture resistance is improved.
Since the moisture permeability coefficient of the resin film is represented by the product of the permeability coefficient and the solubility coefficient, the mechanism of improving the moisture resistance of the tabular pigment is to reduce the permeability coefficient due to the curving effect and to use an α-olefin / unsaturated carboxylic acid copolymer Are two synergistic effects of a decrease in the coefficient of dissolution due to a decrease in the volume fraction of. Due to this synergy,
The coating amount was found that it is possible to produce moisture-proof paper shown unprecedented high moisture resistance (hereinafter moisture permeability 10g / m ² · 24hr) at 20 to 30 g / m ^2. However, when a moisture-proof paper was produced with a small coating amount (about 5 g / m ² , about 3 μm in thickness), the moisture permeability showed a very large value. This is because the orientation of the flat pigment is disturbed due to the unevenness of the paper base,
It was considered that the moisture-proof paint penetrated into the paper base material and the effective film thickness became small. Therefore, a coating composed of a pigment and a binder is coated on a paper base material so as to have a coating amount of 10 to 15 g / m ² to form an anchor layer, and an α-olefin / unsaturated carboxylic acid copolymer is formed thereon. A moisture-proof paper consisting of a flat pigment was applied to produce a moisture-proof paper. The moisture-proof paper thus obtained has a coating amount of 5 g / m ² and a moisture permeability of 30 to 40 g / m ² · 24 hr.
It has been found that the amount of coating, which conventionally required ²⁰ to 30 g / m ² , is greatly reduced. However, the moisture-proof layer composed of such an α-olefin / unsaturated carboxylic acid copolymer and a tabular pigment is disintegrated due to a mechanical action of a pulper or the like. This is presumed to be due to the fact that the tabular pigment becomes the base point and the moisture-proof layer is mechanically destroyed therefrom. However, since the disintegrated pieces of the moisture-proof layer are not sufficiently small, the waste paper is of a low grade (magazine waste paper level) and has a problem that the reusable range is narrow. Here, the present inventors have found that the addition of a vinyl emulsion polymer to the α-olefin / unsaturated carboxylic acid copolymer and the tabular pigment improves the disintegration of the moisture-proof film in water. Increasing the amount of the flat pigment to improve the disintegration can reduce the disintegration pieces of the moisture-proof paper,
If the addition amount is too large, pinholes and agglomerates of plate-like pigments increase in the film, and the moisture-proof property decreases. Therefore, there is a limit in the balance between the disintegration property and the moisture proof property. However, it has been found that when a tabular pigment and an emulsion polymer are used together, particularly when a vinyl-based emulsion polymer having a particle diameter smaller than the average particle diameter of the tabular pigment is used together, the disintegration is further improved. Considering the large disintegration fragments of the moisture-proof layer consisting only of the α-olefin / unsaturated carboxylic acid copolymer and the vinyl emulsion polymer, the disintegration is dramatically improved by using the flat pigment and the vinyl emulsion polymer together. It is surprising that the improvement is achieved. This is presumed to be due to the following mechanism. That is, when the vinyl emulsion polymer is dispersed in the α-olefin / unsaturated carboxylic acid copolymer, the mechanical strength (tensile strength, elongation, etc.) of the moisture-proof layer decreases. When the hard plate-like pigment is dispersed in the moisture-proof layer, the structure of the moisture-proof layer becomes uneven and the mechanical strength further decreases. In particular, when particles having a small particle diameter and a large pigment are mixed in the moisture-proof layer, the non-uniformity of the moisture-proof layer is further increased, so that the mechanical strength is further reduced. It is presumed that it can be done. Even more surprising,
It has been found that the disintegration is further improved by providing the anchor layer. The anchor layer used in the present invention is obtained by blending a pigment such as calcium carbonate or kaolin with a small amount of a binder such as starch or SBR. Since such an anchor layer is brittle, it has a very good disintegration property. The disintegration of the moisture-proof layer provided on this anchor layer is inferior to that of the anchor layer. However, if the moisture-proof layer is provided on the anchor layer, which has excellent disintegration properties, when the moisture-proof paper is disintegrated, the anchor layer is destroyed by the mechanical action and the moisture-proof layer is also destroyed at the same time. It is presumed that the performance is improved. In the present invention, the α-olefin / unsaturated carboxylic acid copolymer exhibits an unprecedentedly high moisture-proof property due to the moisture-proof property of the α-olefin / unsaturated carboxylic acid copolymer, the reduction of the solubility coefficient due to the tabular pigment, and the curve effect. In addition, the disaggregation property is improved by a synergistic effect of the three members of the tabular pigment, the vinyl emulsion polymer and the anchor layer.

As the α-olefin constituting the α-olefin / unsaturated carboxylic acid low molecular weight copolymer usable in the present invention, ethylene, propylene and the like 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.

[0010] Ethylene and acrylic acid or methacrylic acid
The weight average molecular weight of the copolymer (together, referred to as (meth) acrylic acid), and ethylene and the (meth) acrylic acid copolymer 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 blocks the moisture-proof surface and the back surface or the moisture-proof surface and the contents of the package (the phenomenon of fusing or sticking by heat, pressure or time).
It is not preferable because it is easy to do. If the weight average molecular weight exceeds 100,000, the production becomes difficult, and the effects on the moisture resistance, the blocking resistance, and the sliding resistance level off. The α-olefin / unsaturated carboxylic acid low molecular weight copolymer used in the present invention is preferably dispersed in an aqueous medium (latex type) from the viewpoint of film-forming properties. Examples of commercial products that can be used as the latex-type α-olefin / unsaturated carboxylic acid low molecular weight copolymer as described above include Hitec S-3121, 7024, and 3125.
3123 and 3127 (both from Toho Chemical Industry Co., Ltd.)
Product name). Further, an α-olefin / unsaturated carboxylic acid copolymer which is made water-soluble with an alkali (alkali-soluble type) is also preferable from the viewpoint of film-forming properties. As the kind of alkali, amines such as sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia, and alkanolamine are preferable. Among these alkalis, ammonia and amines are preferable from the viewpoint of moisture proofness. In particular, ammonia and amines having a low boiling point (boiling point of 150 ° C. or less) or azeotropic with water evaporate from the moisture-proof film during drying.
It is preferable because the water resistance of the α-olefin / unsaturated carboxylic acid copolymer is improved and the moisture resistance is improved. As the alkali-soluble α-olefin / unsaturated carboxylic acid low molecular weight copolymer as described above, commercially available products can be used. Examples of the commercially available products include Sixen-AC, Sixen-N, and Sixen-
L (all manufactured by Sumitomo Seika Co., Ltd.) and the like. The α-olefin / unsaturated carboxylic acid copolymer can also be used in a type dissolved in a solvent such as alcohols or toluene. The plate-like pigment which can be used in the present invention is, firstly, a phyllosilicate mineral. Can be Those belonging to the phyllosilicate minerals have a plate-like or flaky shape and have distinct cleavage properties, and are composed of mica, pyrophyllite, talc, chlorite, septe chlorite, serpentine, stilp-nomelane, and clay. There are minerals. Among these, minerals having a large particle size and a large amount of output, 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, sodium teniolite, lithium teniolite and the like. 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 flat plate portion but the whole is granular. But,
Among kaolins, delamikaolin, which is obtained by intentionally peeling off the crystal layer and cutting it into a plate, can be used as the plate-like pigment in the present invention. Further, it is preferable that the particle diameter of the plate-like pigment be one 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 second type of the tabular pigment used in the present invention is a so-called inorganic layered compound having a high stacked property and a high tabularity bonded by ions. Specific examples of the inorganic layered compound include graphite, phosphate-based compound (zirconium phosphate-based compound), chalcogen compound [formula MX]
_The dichalcogen compound represented by ₂ is exemplified. Here, M is a group IV (Ti, Zr, Hf) and a group V (V, N
b, Ta) or group VI (Mo, W) element, and X represents chalcogen (S, Se, Te). ].

As a third of the tabular pigments used in the present invention,
Examples include clay minerals such as smectites and vermiculites. More specifically, dickite,
Nacryte, smectite, halloysite, antigorite, chrysotile, pyrophyllite, tetrasilyl mica, sodium teniolite, margarite,
Vermiculite, zansophyllite, chlorite and the like can be mentioned. Smectite is particularly preferred, and montmorillonite, hyderite, nontronite, saponite, iron saponite, hectorite,
Sokonite, stevensite and the like can be mentioned.

The tabular pigment used in the present invention has an average particle diameter of 20 n when dispersed in water or a solvent.
Those between m and 100 μm are suitable, and preferably about 1 μm to 50 μm. Average particle size is 20nm
If it is less than 1, the aspect ratio becomes small, and the effect of improving the moisture resistance is small. On the other hand, when the thickness exceeds 100 μm, the pigment protrudes from the surface of the coating layer, which results in poor appearance and reduced moisture resistance, which is not preferable. The average particle diameter of the tabular pigment used in the present invention dispersed in water or a solvent, the average particle diameter of 0.1 μm or more is a value measured by a particle size distribution analyzer using laser diffraction applying light scattering theory. . In addition, for those having an average particle diameter of 0.1 μm dispersed in water or a solvent, the values are measured using a dynamic light scattering method.

The aspect ratio of the tabular pigment to be used is preferably 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. As the aspect ratio increases, the number of layers in the coating layer of the tabular pigment increases, so that high moisture-proof performance is exhibited. The thickness of the tabular pigment is
It is measured from the cross-sectional photograph of the moisture-proof film. Those having a thickness of 0.1 μm or more are determined by analyzing the 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. Vinyl-based emulsion polymer used for improving disintegration, organic pigments, inorganic pigments,
There is no particular limitation as long as it is dispersed in water or a solvent and is dispersed in a paint composed of an α-olefin / unsaturated carboxylic acid copolymer and a tabular pigment. The blending amount of the α-olefin / unsaturated carboxylic acid copolymer and the tabular pigment is preferably from 95/5 to 30/70 in terms of mass, more preferably from 90/10 to 35/65, particularly preferably from 85/1.
5 to 40/60. When the blending amount of the tabular pigment is less than 5%, the effect of improving the moisture-proof property and the effect of improving the disaggregation property are reduced. When the tabular pigment is larger than 70%, the resin filling the gap between the tabular pigments is insufficient, so that the number of voids and pinholes is increased, and the moisture resistance is deteriorated. The vinyl emulsion polymer used in the present invention is obtained by emulsion polymerization of a vinyl monomer, and has a molecular weight of several tens, unlike the α-olefin / unsaturated carboxylic acid low molecular weight copolymer. Those having a high molecular weight such as ten thousand to several million are generally used. The vinyl 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. Styrene-butadiene-based latex, synthetic rubber-based latex such as methyl methacrylate-butadiene-based latex, styrene-acrylic emulsion, acrylic ester polymer emulsion, polystyrene emulsion, etc. Are listed as vinyl emulsion polymers. The aromatic vinyl monomer is capable of imparting appropriate hardness and water resistance to the obtained vinyl emulsion polymer, and can be selected from, for example, styrene, α-methylstyrene, monochlorostyrene, vinyltoluene, and the like. Styrene is particularly preferred, and a vinyl emulsion polymer containing styrene as a constituent monomer in an amount of 30% by weight or more is particularly preferred because the intended effects of the present invention can be efficiently exhibited. The aliphatic conjugated diene-based monomer 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, and 1,3-butadiene is particularly preferred. The unsaturated carboxylic acid monomer is effective for increasing the adhesive strength of the obtained vinyl emulsion polymer and improving the stability of the vinyl emulsion polymer latex as a colloid. Unsaturated carboxylic acids such as acid, methacrylic acid, crotonic acid, cinnamic acid, itaconic acid, fumaric acid, maleic acid, butenetricarboxylic acid, monoethyl itaconate, monobutyl fumarate and monobutyl maleate; Unsaturated polycarboxylic acid alkyl esters having at least one carboxyl group, and other acidic monomers for the same purpose, such as acrylamidopropanesulfonic acid, sodium sulfoethyl acrylate, sodium sulfopropyl methacrylate. Unsaturated sulfonic acids such as salts or salts thereof Can be mentioned, among these acrylic acid, methacrylic acid, itaconic acid, fumaric acid are preferably used in the present invention. Examples of other copolymerizable monomers include methyl acrylate, methyl methacrylate, unsaturated carboxylic acid alkyl esters such as ethyl acrylate and butyl acrylate, unsaturated nitriles such as acrylonitrile and methacrylonitrile, and acrylic acid β. −
Unsaturated carboxylic acid amides such as hydroxyethyl, β-hydroxypropyl acrylate, and β-hydroxyethyl methacrylate, and unsaturated carboxylic acid amides such as acrylamide, methacrylamide, N-methylolacrylamide, and diacetone acrylamide; and derivatives thereof. And unsaturated carboxylic acid glycidyl esters such as glycidyl acrylate 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.

The vinyl emulsion polymer of the present invention preferably has a glass transition point (Tg) of 10 ° C. or higher, and the glass transition point (Tg) varies slightly depending on the measuring method. However, in the present invention, the value measured with a differential calorimeter was used as a reference. If the glass transition temperature is less than 10 ° C., the disintegration properties are remarkably poor, and may not be suitable for the purpose of the present invention.

The particle size of these vinyl emulsion polymers is 10
nm to 20 μm, more preferably 20 nm to
10 μm. If the particle size is less than 10 nm, the effect on the improvement of the disintegration is small. On the other hand, if it is larger than 10 μm, the particles may penetrate the entire moisture-proof film or an extremely thin portion may be formed, so that the moisture-proof property is reduced. Further, a vinyl emulsion polymer having an average particle diameter smaller than the average particle diameter of the tabular pigment to be used is preferable in view of the disintegration property. The mixing amount of these vinyl emulsion polymers is preferably 5 to 100 parts, more preferably 10 to 100 parts by mass in terms of the total of the α-olefin / unsaturated carboxylic acid copolymer and the tabular pigment.
Parts to 80 parts, particularly preferably 15 to 60 parts. When the amount is less than 5 parts, the effect of improving the disintegration is small, and
If the amount is more than 10 parts, the moisture resistance deteriorates. Further, two or more kinds of vinyl emulsion polymer, inorganic pigment and organic pigment may be used in combination. In the moisture-proof laminate of the present invention, the coating amount of the moisture-proof paint for forming the moisture-proof layer is 1 solid content.
５０50 g / m ² is preferred, and 2-40 g / m ² is more preferred. When the coating amount is less than 1 g / m ² , there is a problem that it is difficult to obtain a sufficient moisture-proof property. on the other hand,
When the coating amount is more than 50 g / m ² , not only is the moisture-proofing leveled out, which is uneconomical, but also the disadvantage that the disintegration of the laminate deteriorates.

The moisture-proofing agent reacts with the α-olefin / unsaturated carboxylic acid copolymer to modify it to be hydrophobic,
Or cross-linking it to make it hydrophobic, or to coat the plate-like pigment, or to make the plate-like pigment hydrophobic, or to promote the lamination orientation parallel to each other, or to use α-olefin / unsaturated carboxylic acid By increasing the adhesiveness with the copolymer and / or tabular pigment, or by filling these gaps,
This is to improve the moisture-proof property of the moisture-proof layer.

The moisture-proofing agent used in the present invention is, for example, the following: a urea-formaldehyde condensation reaction product, a melamine-formaldehyde condensation reaction product, an aldehyde compound having 1 to 8 carbon atoms, and one or more epoxy compounds. Epoxy compound having a group, crosslinking reactive polyvalent metal compound, organoalkoxysilane compound, organoalkoxy metal compound, organic amine compound, polyamide compound, polyamide polyurea compound, polyamine polyurea compound, polyamide amine polyurea compound, polyamide amine 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 - preferably comprises at least one selected from epihalohydrin or formaldehyde condensation reaction products.

Among the compounds used in 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 carboxylic acid. It reacts with an acid copolymer, and in particular, undergoes a hydrogen bond or a dehydration reaction with its carboxylic acid group to crosslink the polymer or copolymer molecule and render it hydrophobic and water-insoluble (three-dimensional network structure). be able to. Further, the condensation product, even if it does not chemically react with the α-olefin / unsaturated carboxylic acid copolymer, stably binds the α-olefin / unsaturated carboxylic acid copolymer and the tabular pigment. 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-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 react 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 and the like. A ring-opening addition reaction with a carboxylic acid contained in the copolymer can be made hydrophobic and water-insoluble.
Further, the epoxy compound, during the heating and drying of the moisture-proof layer, 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, aluminum alkoxide and the like. The metal can coordinate or covalently bond 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. it can.

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 both,
The formation of gaps 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 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 its hydrophilic portion, and includes, for example, isopropyl triisostearoyl titanate, isopropyl trioctano 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 of 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 of the inorganic surface by the thermal dehydration reaction,
It is. 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, regarding the hydrophobic group portion of the coupling agent, when the hydrophobic group portion is an organic oligomer, a high molecular weight organic film is formed on the surface of the inorganic compound, and the surface is completely hydrophobized to form a synthetic resin matrix. 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
Crosslinks with olefin / unsaturated carboxylic acid copolymer, α
Adhesion to 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-proofing agent in the present invention is prepared by mixing a coupling agent with a coating liquid comprising an α-olefin / unsaturated carboxylic acid copolymer and a tabular pigment. The obtained coating liquid may be applied to the surface of a paper support and dried to form a coating. Alternatively, the surface of the tabular pigment may be treated in advance with a coupling agent and 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 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 a tabular pigment is previously treated with a coupling agent, and includes a dry method and a wet method. In the dry method, a powdery flat pigment is put into a mixer,
This is a method of adding a coupling agent after preheating and stirring at high speed under heating, and the wet method is to add a coupling agent and a plate-like pigment in water, a solvent or a mixture thereof, and then stir at high speed. This is a method to obtain a powder by drying. The use of the coupling agent is slightly inferior to the pretreatment method in the integral blending method, but is excellent in workability because there is no step of pretreatment of the tabular pigment.

When treating a tabular pigment in an aqueous treatment system in an integral blending method or a wet pretreatment method,
In order to increase the water solubility of the coupling agent, it is preferable to use a methoxy group, an ethoxy group, or an isopropoxy group having a relatively low hydrophobicity as the alkoxy group, and the hydrophobic group of the coupling agent includes a hydrophilic epoxy group. , An amino group and a 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. If the amount of the coupling agent is less than 0.1 part by weight, the effect of the coupling agent on the surface of the plate-like pigment may be insufficient due to insufficient coating of the surface of the flat pigment. 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, so that when the aqueous dispersion is used, it becomes thick and cannot be coated, or the dispersion becomes poor and the aggregates become poor. 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 or sodium dialkyl sulfosuccinate.

In the present invention, the organic amine compound and the polyamide compound used as a moisture-proofing agent have cationic properties, and when they come into contact with a tabular pigment exhibiting anionic properties, their soft aggregation and lamination orientation parallel to each other are caused. And the moisture-proof performance of the moisture-proof layer can be improved.

In the present invention, the carboxylic acid group contained in the α-olefin / unsaturated carboxylic acid copolymer reacts with an organic monoamine, an organic polyamine or an organic quaternary ammonium salt to form an α-olefin / unsaturated carboxylic acid. The hydrophobicity or water insolubility of the copolymer 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-mentioned 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, tetrachloroxylenediamine, 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, the reaction product of tall oil and diethyltriamine, the reaction product of linolenic acid dimer and tetraethylpentamine, and the reaction product of triethylenetetramine and saturated dibasic acids (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 polyamide compound is generally 100 to 1000.
However, there is no particular limitation.

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, such as butylene oxide, octylene oxide, butyl glycidyl ether, styrene oxide, phenyl glycidyl ether, glycidyl methacrylate, allyl glycidyl ether, and 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 an insoluble one may be dispersed in water using a surfactant or the like in an amount of 0.1 to 3% by weight based on the monofunctional epoxy compound. Can be used.

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 part 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,
May be economically disadvantaged.

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

In the present invention, the polyamide polyurea compound, the polyamine polyurea compound, the polyamidoamine polyurea compound and the polyamidoamine compound used as the moisture proofing agent are (i) polyalkylene polyamine or alkylene polyamine, (ii) urea , (Iii) a dibasic carboxylic acid, and optionally (iv) aldehydes,
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, when a 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 aldehydes and epihalohydrins are used, it is preferable that the amount of the aldehydes or epihalohydrins used is very small, or that self-crosslinking occurs during the synthesis process so that almost no free methylol group or epoxy group remains. In the above reaction, the polyalkylene polyamine or the alkylene polyamine (i) is used without using the urea number (ii).
And a dibasic carboxylic acid to give a polyamidoamine compound. The reaction amount of the component (iv) aldehydes, epihalohydrins, and α, γ-dihalo-β-hydrins is 5 to 3 with respect to 100 moles of the component (i).
Preferably it is in the range of 00 moles.

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 thereof include diazadecane-1,10-diamine, ethylenediamine, propyldiamine, 1,3-propanediamine, and hexamethylenediamine. 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 include succinic acid, glutaric acid, adipic acid, sebacic acid,
Examples include maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, and hexahydrophthalic acid. 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 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 the 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. The following method can be used as an example of the synthesis method. That is, an alkylene diamine or a 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 used as a moisture proofing agent show a slight cationic property in an aqueous coating solution, and It is considered that the tabular pigment having the property is softly agglomerated in the process of forming the film, 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. In addition, among the above compounds, those having an epoxy ring and / or a methylol group in the molecule thereof are included, and the content of these functional groups is very small. / Or most of the methylol group-forming compound self-crosslinks,
The effect of these functional groups is negligible. Therefore, the moisture-proof layer containing the above compound as a moisture-proof property improving agent easily disintegrates from the paper support when collecting and regenerating moisture-proof paper, and hardly inhibits the disintegration of the recycled pulp.

In the present invention, the moisture-proofing agent is used in an amount of 0.05 to 3 based on the total mass of the α-olefin / unsaturated carboxylic acid copolymer and the tabular pigment as 100 parts by mass conversion.
0 parts by weight, preferably 0.5 to 20 parts.
It is more preferably 1 part by weight, particularly preferably 1 part by weight. If the amount is less than 0.1 part, the effect of improving the moisture resistance may be insufficient. If the amount exceeds 30 parts, the effect of improving the moisture resistance may be saturated, which is economically disadvantageous. May be. Further, a moisture-proofing agent composed of two or more compounds may be used.

In the moisture-proofing agent used in the moisture-proof laminate 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, A valent metal compound and an organic amine compound,
The coupling agent may include one or more selected from polyamide compounds and the like, and the coupling agent may include one or more selected from the aforementioned organoalkoxysilane compounds and organoalkoxy metal compounds. Further, the amount of the carboxylic acid contained in the α-olefin / unsaturated carboxylic acid copolymer is more preferably at least 5 mol% in terms of acid modification.

The anchor layer in the present invention is provided in order to prevent a decrease in moisture resistance due to unevenness of the substrate and to prevent a decrease in the effective film thickness of the moisture-proof layer due to the absorption of moisture by the moisture-proof paint by the substrate. Such an anchor layer is preferably composed of a pigment and an adhesive aqueous resin, and the pigments used include calcium carbonate, kaolin, clay, talc, titanium oxide, zinc oxide, aluminum hydroxide, amorphous silica, and plastic pigment. Examples of the adhesive aqueous resin include water-soluble resins such as starch, casein, polyvinyl alcohol and modified products thereof, styrene / butadiene-based latex, (meth) acrylic ester-based latex, and (meth) acrylic-styrene-based resin. Some are made of synthetic resin latex such as latex. In addition, the preferred blending (mass) ratio (solid ratio) of these pigments and the adhesive resin
Is from 5:95 to 50:50. The coating amount is preferably 3 to 30 g / m ² in terms of solid content. If it is less than 3 g / m ² , it is difficult to obtain a flat surface by covering the unevenness of the paper support,
Even if it exceeds 30 g / m ² , the effect of undercoating is saturated. If necessary, a dispersant such as a polycarboxylic acid, an antifoaming agent, a surfactant, a water retention agent, a color adjusting agent and the like can be added.

The overcoat in the present invention improves the moisture-proof property by filling the pinholes of the moisture-proof layer or filling the minute voids. Therefore, there is no particular limitation as long as it is an overcoat containing a resin having good film-forming properties and good water resistance. Examples of the resin include an α-olefin / unsaturated carboxylic acid copolymer, a styrene-butadiene-based latex, an acrylic ester-based emulsion, and a polyester-based emulsion. Of these, α-olefin / unsaturated carboxylic acid copolymers are preferred in terms of moisture resistance, and alkali-soluble α-olefin / unsaturated carboxylic acid copolymers are particularly preferred in terms of pinhole permeability. is there. If necessary for the anchor coating paint, moisture-proof paint, overcoat paint of the present invention,
A dispersant such as polycarboxylic acid, a defoaming agent such as silicone, a surfactant, a water retention agent, a color adjusting agent and the like can be added.

Such a 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 is mainly composed of pulp which is easily dispersed in water by mechanical disaggregation, but is generally used bleached or unbleached. Kraft paper (acid paper or neutral paper) or paperboard used for cardboard, building materials, white balls, chip balls, etc., is preferred, and more preferably a yanke dryer. For example, single-coated glossy paper which has been subjected to forced drying or bleached / unbleached kraft paper which has been subjected to a calendar treatment. When such a paper base material is used, the moisture-proof layer is formed from the highly smooth base material surface. The orientation of the tabular pigments in the thickness direction is easy to arrange uniformly and in parallel without disturbing the coating surface, so that the moisture-proof performance is also significantly improved.

[0058]

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.

<Coating for anchor>
Synthetic resin latex (trade name S269) was added and mixed with 100 parts (trade name: Amazon, manufactured by CADAM).
4I-1, made by Nippon Synthetic Rubber, solid content concentration: 50.4%) 2
4 parts, 40 parts of a 5% solids aqueous solution of starch (trade name: PC30A, manufactured by Sanwa Starch Industries), 3% ammonia water 10
The parts were mixed and stirred to obtain an anchor paint.

<Moisture-proof paint 1> Synthetic mica in 100 parts of water
(Synthetic fluorophlogopite, composition formula KMg_ThreeAlSi_ThreeO
_TenF _Two, Average particle diameter 20 μm, aspect ratio 60,
-Industrial, trade name: PDM-9L-20) 30 parts added
After stirring, the ethylene acrylic acid copolymer
Rejon (trade name: S-3121, manufactured by Toho Chemical Co., molecular weight 2)
7,500, acrylic acid / ethylene copolymerization ratio = 15/8
5, solid content 30%) 150 parts were added and stirred (flat face)
Ratio of filler and α-olefin / unsaturated carboxylic acid copolymer
= 40/60). In addition, this water-based paint is
Coalescing (polystyrene latex, trade name L8801, Asahi
Kagaku, Tg = 109 ° C, average particle size 200nm)
The moisture-proof paint 1 was prepared by adding 30 parts of 48%.

<Moisture-proof paint 2> Natural mica (muscovite, composition formula K ₂ O.3Al ₂ O ₃ .6SiO ₂ .2) was added to 100 parts of water.
After adding 30 parts of H ₂ O, an average particle diameter of 18 μm, an aspect ratio of 20, and a product name of FA-500 (manufactured by Yamaguchi Mica Corporation),
After stirring, a 5% aqueous solution of a silane coupling agent (N-β (aminoethyl) γ-aminopropyltrimethoxysilane, trade name: KBM603, manufactured by Shin-Etsu Chemical Co., Ltd.) was added to 6
Parts (addition of 1% to natural mica) and stirred, and the cationic resin (polyamide polyurea-formalin resin,
Trade name: Sumireze Resin 302, manufactured by Sumitomo Chemical Co., Ltd., solid content 60%) was added and stirred. 150 parts of an aqueous ethylene acrylic acid copolymer solution (trade name: Seixen-AC, manufactured by Sumitomo Seika Co., Ltd., molecular weight: 25,000, acrylic acid / ethylene copolymerization ratio = 15/85, solid content: 30%, ammonia neutralized type) are added and stirred. (The mixing ratio of the tabular pigment and the α-olefin / unsaturated carboxylic acid copolymer = 40/6)
0). In addition to this water-based paint, polystyrene latex
(Trade name: L8801, manufactured by Asahi Kasei Corporation, Tg = 109 ° C., average particle diameter: 200 nm), solid content: 48%) was added and stirred to prepare a moisture-proof coating material 2.

<Moisture-proof paint 3> Synthetic mica in 100 parts of water
(Synthetic fluorophlogopite, composition formula KMg_ThreeAlSi_ThreeO
_TenF _Two, Average particle diameter 20 μm, aspect ratio 60,
-30 parts of industrial product, trade name PDM-9L-20) was added,
After stirring, the carboxylic acid-modified SBR latex (Carbo
Acid-modified styrene-butadiene latex, trade name S1
X2, manufactured by Zeon Corporation, acid modification rate: about 20%, Tg: 18
90 ° C., solid content concentration: 50%)
A moisture-proof paint 3 was prepared (a flat pigment and an SBR latex).
Is 40/60).

<Moisture-proof paint 4> Synthetic mica in 100 parts of water
(Synthetic fluorophlogopite, composition formula KMg_ThreeAlSi_ThreeO
_TenF _Two, Average particle diameter 20 μm, aspect ratio 60,
-Industrial product, trade name: PDM-9L-20) 30 parts added
After stirring, the ethylene acrylic acid copolymer
Rejon (trade name: S-3121, manufactured by Toho Chemical Co., molecular weight 2)
7,500, acrylic acid / ethylene copolymerization ratio = 15/8
5, solid content 30%) 150 parts were added and stirred, and the moisture-proof paint 4
Was prepared (flat pigment and α-olefin / unsaturated carb
(A compounding ratio of the acid copolymer = 40/60).

Example 1 Anchor paint was applied to one side of unbleached kraft paper (70 g / m ² , thickness 100 μm) with a Mayer bar so that the coating amount (as solid) was 15 g / m ^2. After the work, the coating was dried at 120 ° C. for 1 minute to form an anchor layer. The moisture-proof paint 1 was applied on this 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 An anchor paint was applied to one surface of unbleached kraft paper (70 g / m ² , thickness 100 μm) with a Mayer bar so that the coating amount (as a solid) was 15 g / m ^2. 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, and then dried at 130 ° C. for 2 minutes to obtain a moisture-proof laminate.

Example 3 An anchor paint was applied to one surface of unbleached kraft paper (70 g / m ² , thickness 100 μm) using a Mayer bar so that the coating amount (as a solid) was 15 g / m ^2. 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 25 g / m ² as a solid content, and then dried at 130 ° C. for 2 minutes to obtain a moisture-proof laminate.

<Comparative Example 1> Unbleached kraft paper (70 g / m
² , a thickness of 100 μm) was applied with a Mayer bar so that the coating amount was 5 g / m ² with the moisture-proof coating material 1 as a solid content, followed by drying at 130 ° C. for 2 minutes to obtain a moisture-proof laminate.

Comparative Example 2 Ethylene acrylic acid copolymer emulsion (trade name: S-3121, manufactured by Toho Chemical Co., Ltd., molecular weight: 27500, acrylic acid / ethylene copolymerization ratio = 15 /
85, 30% solids) with unbleached kraft paper (basis weight 70 g /
(m ² , thickness 100 μm) was applied with a Mayer bar so as to have a solid content of 25 g / m ² and dried at 130 ° C. for 2 minutes to obtain a moisture-proof laminate.

Comparative Example 3 An anchor paint was applied to one surface of unbleached kraft paper (70 g / m ² , thickness 100 μm) with a Mayer bar so that the coating amount (as a solid) was 15 g / m ^2. Thereafter, drying was performed at 120 ° C. for 1 minute to form an anchor layer. The moisture-proof paint 3 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 4> The moisture-proof paint 4 was applied to one side of unbleached kraft paper (basis weight 70 g / m ² , thickness 100 μm) using a Meyer bar so that the dry coating amount was 5 g / m ^2. And dried by heating at 110 ° C. for 2 minutes using a hot air circulation dryer to form a moisture-proof layer, thereby obtaining a moisture-proof laminate. The obtained moisture-proof laminate was subjected to the test. Table 1 shows test results
Shown in

<Test Method> 1) Moisture Permeability JIS-Z-0208 (cup method) B method (40 ° C. 90%
(RH) with the moisture-proof coated side facing out. As a standard of moisture permeability, if it is 50 g / m ² · 24 hours or less, there is practicality. 2) Disintegration property A 45 g portion of the moisture-proof laminate was cut into a square of about 5 cm, and the resultant was cut in 1500 g of water using a TAPPI disintegration standard machine (disintegrator, 2 liter container).
Disintegrated for minutes. The obtained slurry was used as a handmade sheet having a basis weight of 60 g / m ^{2 in} a laboratory handmade machine. The size of the undisintegrated material (film piece, paper piece) is visually evaluated, and the size (long axis) of the disintegrated piece is less than 1 mm, ○, 1 to 5 m
m was rated as Δ, and greater than 5 mm was rated as x. If the size of the defibrated pieces is 5 mm or less, it can be used as waste paper.

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[Table 1]

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According to the present invention, there is provided a moisture-proof laminate (having water disintegration properties) which can be reused as used paper, and has a remarkably improved moisture resistance and excellent disintegration properties. Is possible.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) D21H 21/16 D21H 21/16 21/52 21/52 F term (Reference) 4F100 AC05 AK03B AK12 AK70B AL05B AR00C AT00A BA03 BA07 BA10C CA13B CA13H CA30B CC00C DE02B DE02H DG10A EH46 EJ65 GB15 GB71 JA05B JA07B JB06 JB06B JD04B JL16 YY00B 4L055 AG07 AG27 AG38 AG59 AG63 AG71 AG76 AG78 AG89 AG94 AH02 AH23 AH37 AJ01 AH01

Claims (7)

[Claims] 1. A moisture-proof laminate comprising an anchor layer provided on at least one side of a support and a moisture-proof layer provided on the anchor layer, wherein the moisture-proof layer comprises the following components. (1) Tabular pigments. (2) α-olefin / unsaturated carboxylic acid copolymer. (3) A vinyl emulsion polymer. 2. The method according to claim 1, wherein the α-olefin / unsaturated carboxylic acid copolymer is an ethylene / acrylic acid or ethylene / methacrylic acid copolymer having a molecular weight of 5,000 to 100,000. Moisture proof laminate. 3. A glass transition point (Tg) of a vinyl emulsion polymer.
The moisture-proof laminate according to claim 1, wherein the temperature is 10 ° C. or higher. 4. The method according to claim 1, wherein the average particle size of the vinyl emulsion polymer is not more than the average particle size of the tabular pigment.
4. The moisture-proof laminate of any one of claims 1 to 3. 5. The moisture-proof laminate according to claim 1, wherein the moisture-proof layer contains a moisture-proof property improver. 6. The moisture-proof laminate according to claim 1, wherein the anchor layer contains a pigment and an aqueous adhesive resin. 7. The moisture-proof laminate according to claim 1, further comprising an overcoat layer on the moisture-proof layer.