JPH11189996A - Readily disintegrable moistureproof paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject paper with sufficient moistureproofness even if allowed to leave in folded state, by providing at least one side of a substrate paper with a moistureproof layer comprising a phyllosilicate compound and a synthetic resin. SOLUTION: This moistureproof paper provided with moistureproof layer(s) is obtained by coating at least one side of a substrate paper such as bleached or unbleached kraft paper with a coating liquor comprising a phyllosilicate compound such as muscovite or sericite, a synthetic resin >=90% in gel fraction and -40 to 40 deg.C in glass transition temperature such as a styrene-butadiene- based copolymer, an ether compound bearing at least one hydroxyl group such as 2-butoxyethanol or a polyether compound bearing at least one hydroxyl group and 2-30 oxygen atoms forming ether linkages such as polyoxyethylane phenyl ether, and an active hydrogen-reactive compound such as polymide- polyurea resin.

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 having excellent disintegration properties and having sufficient moisture-proof properties even when creased.

[0002]

2. Description of the Related Art Conventionally, for packaging of industrial and industrial products,
To prevent moisture and water absorption of the contents, polyolefin laminated paper (hereinafter referred to as poly-laminate paper) is used in which a polyolefin-based polymer compound such as polyethylene or polypropylene with excellent moisture resistance and water resistance is laminated on a paper support. Have been. For example, poly-laminated paper is used for packaging for winding paper products, flat-format packaging such as art paper and coated paper, packaging for small-diameter paper stacks such as electrophotographic copying paper and inkjet paper, and heavy materials such as cement and resin. Used for bags. However, these poly-laminated papers have poor disintegration properties due to the strong coating layer, and when recovered as waste paper and used as a raw material for pulp, the coating itself remains in a large sheet shape during disintegration, and the fragmented coating is used in the papermaking process. If mixed in, there will be various problems such as fusing to a cylinder dryer or the like. For this reason, polylami paper cannot be used as waste paper, and is currently incinerated after use.

On the other hand, as a method for producing an easily disintegrating paper having moisture resistance, for example, Japanese Patent Publication No. 55-22597,
JP-A-59-66598 is known. These are obtained by applying an aqueous emulsion obtained by blending a wax emulsion with a synthetic rubber latex on the paper surface. Such easily disintegrating moisture-proof paper has sufficient moisture-proof and waterproof properties and can be disaggregated as used paper, but the wax in the moisture-proof layer precipitates (bleed) on the surface of the moisture-proof layer and is transferred to the opposite back side of the moisture-proof paper. There is a problem that it becomes slippery and the wax is transferred to the contents and contaminates the contents. Also,
Paper manufactured using such moisture-proof paper containing wax as a raw material also has a problem that the wax makes the paper slippery.

The inventors of the present invention have examined the problems of the moisture-proof paper having a moisture-proof layer containing the above-mentioned wax from various viewpoints.
A moisture-proof paper having a moisture-proof layer containing no wax, that is, a paper support, and a moisture-proof layer formed on at least one surface of the paper support, wherein the moisture-proof layer is (a) moisture-proof and film-forming. A moisture-proof paper containing a synthetic resin, (b) flat phyllosilicate compound particles having an average particle size of 5 to 50 μm and an aspect ratio of 5 or more, and (c) a moisture-proofing agent has been previously proposed. No. 8-249647).

[0005] However, when the moisture-proof paper is disintegrated, it is sufficiently disintegrated by using a device having a strong disintegration force such as a refiner or a kneader, but in the case of a device having a weak disintegration force such as a pulper, the disintegration is required. There is a problem that time becomes very long. According to the study of the present inventors,
It was found that if the gel fraction of the synthetic resin used is 90% or more, the resin can be sufficiently separated and disintegrated even with a weak disintegration force like a pulper. When the gel fraction of the synthetic resin is 90% or more,
Since the molecular motion of the dried film after the application of the moisture-proof layer is suppressed by heat during drying, the entanglement of the molecules between the particles of the synthetic resin is weakened, and it is estimated that the particles are weakly fused. For this reason, the elongation of the moisture-proof layer coating is reduced, and the disintegration is improved. However, since such a moisture-proof layer has poor plasticity, the moisture-proof layer is easily damaged by creases in the moisture-proof paper, which causes a problem that the moisture-proof property deteriorates.

SUMMARY OF THE INVENTION An object of the present invention is to provide a moisture-proof paper which is excellent in defibration properties and has a sufficient moisture-proof property even when creased.

[0006]

A first aspect of the present invention is a moisture-proof paper having a moisture-proof layer comprising a phyllosilicate compound and a synthetic resin on at least one surface of a paper support, wherein the gel fraction of the synthetic resin is 90%. Above and a glass transition temperature of −10 ° C.
-40 ° C, and the moisture-proof layer has an ether compound containing at least one or more hydroxyl group, or an ether compound containing at least one or more hydroxyl group and having 2 to 30 oxygen atoms forming an ether bond. An easily disintegrating moisture-proof paper comprising a polyether compound contained therein.

A second aspect of the present invention is a moisture-proof paper, wherein the phyllosilicate compound is treated with a coupling agent. A third aspect of the present invention is a moisture-proof paper, wherein the synthetic resin is a styrene-butadiene-based copolymer. A fourth aspect of the present invention is a moisture-proof paper, wherein the moisture-proof layer contains an active hydrogen-reactive compound.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The phyllosilicate compound used in the present invention is a tabular pigment. Those belonging to the phyllosilicate compounds are plate-like or flaky and have distinct cleavages, mica, pyrophyllite, talc, chlorite, septe chlorite, serpentine, stilp-nomelane, There are clay minerals. Of these, mica and talc are preferred. Mica tribe includes muscovite (muscovite), sericite (sericite), biotite (flokopite), biotite (biotite), fluorophlogopite (artificial mica), red mica, soda mica, vanadin mica, illite, Chin mica, paragonite, brittle mica and the like.

[0009] Of these phyllosilicate compounds, muscovite or sericite is preferred in view of the particle size, aspect ratio and the like. In the present invention, any pigment may be used as long as it retains tabularity, but a more preferable average particle size (measured by a laser diffraction method) range is 1 μm to 100 μm.
μm, more preferably 5 μm to 5 μm.
50 μm. When the average particle diameter is 5 μm or less, the orientation of the tabular pigment in the coating layer is hardly parallel to the support, and when the average particle diameter is 50 μm or more, a part of the tabular pigment protrudes from the coating layer, As the thickness of the pigment becomes about several μm, the number of layers of the oriented flat pigment in the coating layer decreases, and the effect of improving the moisture-proof performance decreases. The preferred aspect ratio (the value obtained by dividing the average particle diameter by the thickness; the thickness was measured by observation with an electron microscope) is 5 or more, and particularly preferably a tabular pigment having an aspect ratio of 10 or more. . When the aspect ratio is 5 or less, the film cannot be oriented in parallel to the coating surface, so that the moisture-proof performance is inferior. The larger the aspect ratio, the larger the number of layers of the tabular pigment in the coating layer, so that high moisture-proof performance is exhibited.

The synthetic resin used in the present invention is styrene-
Butadiene-based copolymer, acrylic-styrene-based copolymer, methacrylate-butadiene-based copolymer, acrylonitrile-butadiene-based copolymer, acrylic-based copolymer, polyester-based copolymer, polyurethane-based copolymer Can be Among them, a styrene-butadiene copolymer is preferred. Styrene-butadiene copolymer (SBR) is composed of aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, pt-butylstyrene, chlorostyrene and butadiene, 1,3-butadiene, isoprene, 2,3 It is a copolymer latex obtained by emulsion-polymerizing a monomer comprising a conjugated diene compound such as dimethyl-1,3-butadiene, 1,3-pentadiene and other compounds copolymerizable therewith. Styrene is preferred as the aromatic vinyl compound, and 1,3-butadiene is preferred as the conjugated diene compound.

Other copolymerizable compounds include unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; unsaturated polycarboxylic acids such as fumaric acid, maleic acid, itaconic acid and butenetricarboxylic acid; Partially esterified products of ethylenically unsaturated polycarboxylic acids such as monoethyl acrylate and monomethyl itaconate; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-amyl (meth) acrylate ,
Isoamyl (meth) acrylate, n (meth) acrylate
-Hexyl, 2-ethylhexyl (meth) acrylate,
(Meth) acrylates such as n-octyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; cyano group-containing ethylenically unsaturated compounds such as (meth) acrylonitrile; glycidyl (meth) acrylate; Glycidyl ether of an ethylenically unsaturated acid of the formula:
Glycidyl ethers of unsaturated alcohols such as allyl glycidyl ether; (meth) acrylamide-based compounds such as (meth) acrylamide, N-methylol (meth) acrylamide, and N-butoxymethyl (meth) acrylamide are used. One or more of the above compounds can be used. Among these, unsaturated carboxylic acids having an active hydrogen, unsaturated polycarboxylic acids, and (meth) acrylamide compounds are preferred.

Although the composition ratio of each component of the monomer is appropriately selected, usually, 25 to 75 parts by weight of an aromatic vinyl compound,
Preferably 30 to 70 parts by weight, conjugated diene compound 20 to
60 parts by weight, preferably 25 to 50 parts by weight, and 0 to 50 parts by weight of other copolymerizable compounds. The gel fraction of the synthetic resin (% by weight of the insoluble portion when tetrahydrofuran is used as a solvent) is preferably 90% or more. When the gel fraction is less than 90%, the disintegration of the obtained moisture-proof paper becomes poor. In order to increase the gel amount, the amount of a chain transfer agent (molecular weight modifier) such as alkyl mercaptan or carbon tetrachloride is reduced, or a crosslinkable monomer such as divinylbenzene is copolymerized. The glass transition temperature (Tg) of the synthetic resin is from -10C to 40C, more preferably from -5C to
35 ° C. If the Tg is lower than -10 ° C, the disintegration becomes poor and blocking tends to occur. On the other hand, when Tg is higher than 40 ° C., the moisture-proof property deteriorates. The phyllosilicate compound and the styrene-butadiene-based latex used in the present invention have a compounding (solid content) ratio of 3%.
0: 70-70: 30, preferably 35: 65-60:
40.

Further, in the present invention, ethers are added for the purpose of selectively filling the voids between the particles formed when the emulsion particles are dried / coated to impart plasticity to the moisture-proof layer and increase the resistance to bending. Compounds or polyether compounds can be used. The ether compound or polyether compound used at this time is a linear compound having at least one ether bond (R-O-R) and a hydroxyl group in the main chain. For example, as the ether compound, 2-methoxyethanol (methyl cellosolve), 2-butoxyethanol (butyl cellosolve),
2-isobutoxybutanol, 2-hexyloxyethanol, 1,2-diethoxyethane, 1-acetoxy2
-Methoxyethane, 1,2-diacetoxyethane, 2-
Phenoxyethanol (ethylene glycol monophenyl ether) and the like. Among these, 2-butoxyethanol and 2-phonoxyethanol are preferred. Polyether compounds include polyethylene oxide (polyethylene glycol), polypropylene oxide (polypropylene glycol), polyoxyethylene polypropylene glycol, polyethylene glycol ester, polyethylene glycol ether, polypropylene glycol ester, polypropylene glycol ether, polyoxyethylene polypropylene glycol ester, and polyoxyethylene. Examples include ethylene polypropylene glycol ether, polyoxyethylene alkylamino ether, and polyoxyethylene rosin ester. Among these, polyethylene glycol ether is preferred. In this case, the number of oxygen atoms forming an ether bond in polyethylene glycol ether is 2
It is preferable that the number be in the range of from 30 to 30. 3 oxygen atoms
Those having a value of 0 or more are not preferred because the hydrophilic property is too strong and the moisture-proof property is reduced. Among polyethylene glycol ethers, polyethylene glycol alkyl ether,
Polyethylene alkyl phenyl ether, polyethylene phenyl ether, polyoxyethylene benzyl alcohol ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene β-naphthol ether, and polyoxyethylene bisphenol A ether are preferred. As the alkyl group of the polyethylene glycol alkyl ether, a decyl group, a lauryl group, a cetyl group,
Examples of the stearyl group, oleyl group, coconut alcohol group, and alkylphenyl group of polyethylene glycol alkylphenyl ether include an octylphenyl group, a nonylphenyl group, a dodecylphenyl group, and a dinonylphenyl group.

Each of these ether compounds or polyether compounds is preferably hydrophilic and easily soluble in water, liquid at room temperature, and having an aromatic ring. The compounding amount is from 0.1 to the total weight of the synthetic resin and the tabular pigment.
10% by weight is most preferred. In this case, the compounding amount is 0.1
If it is less than the weight percentage, sufficient plasticity cannot be obtained, and the effect on bending is lost. If the content exceeds 10% by weight, not only does the effect level off, but also the moisture resistance deteriorates.

Examples of the coupling agent used in the present invention include a silane coupling agent containing Si in the hydrophilic group, a titanate coupling agent containing Ti in the hydrophilic group, and an aluminum coupling agent containing Al in the hydrophilic group. Is mentioned. The structure of the coupling agent is roughly classified into a hydrophilic group that interacts with an inorganic compound such as a phyllosilicate compound, and a hydrophobic group that interacts with an organic compound such as a resin.
Particularly, the hydrophilic group portion is obtained by hydrolyzing a metal element such as Ti or Al or an alkoxy group bonded to Si.

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, and the surface is completely hydrophobicized to adhere to the resin matrix. It has the effect of enhancing the nature. When the hydrophobic group has a reactive organic functional group such as an epoxy group, a vinyl group, or an amino group, the functional group and the reactive functional group of the resin matrix are cross-linked to further improve the adhesiveness with the resin matrix. Increase. The coupling agent includes γ-glycidoxypropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyl Trimethoxysilane, methyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, vinylacetoxysilane, γ-chloropropyltrimethoxysilane, γ
-Anilinopropyltrimethoxysilane, isopropyltri (N-aminoethylaminoethyl) titanate and the like.

The phyllosilicate compound is subjected to a surface treatment by an integral blend method or a pretreatment method using such a coupling agent before use. The integral blending method is a method in which a coupling agent is directly added to a paint containing a phyllosilicate compound and a synthetic resin latex. The pretreatment method is a method in which the surface of a phyllosilicate compound is treated in advance with a coupling agent. The addition amount of the coupling agent is 0.1 to 100 parts by weight of the phyllosilicate compound.
It is 5 parts by weight, preferably 0.5 to 2 parts by weight. If the amount is less than 0.1 part by weight, the surface of the phyllosilicate compound is not sufficiently coated with the coupling agent, which is not preferable. If the amount exceeds 5 parts by weight, the effect of the coupling agent will level off. Economy.

The active hydrogen reactive compound used in the present invention reacts with an active hydrogen functional group such as a carboxyl group, an amide group or a hydroxyl group contained in the synthetic resin to crosslink the synthetic resin latex to form a polymer (three-dimensional network). Structure).
Such active hydrogen-reactive compounds include (1) those having a methylol group and causing a dehydration-condensation reaction with the hydrophilic functional group (melamine-formaldehyde resin, urea-formaldehyde resin, etc.); (2) having an aldehyde group. (3) Those having an epoxy group and causing a ring-opening addition reaction with the above-mentioned hydrophilic functional group (polyglycidyl ether, etc.); A compound having a valent metal and forming a coordination bond and a covalent bond with the hydrophilic functional group (such as zirconium carbonate); (5) a compound which is cationic in an aqueous solution and forms an ionic bond with an anionic functional group (polyamine) Compounds, cationic resins such as polyamideamine resins and polyamide epichlororesins). The amount of the active hydrogen-reactive compound is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the synthetic resin latex. The amount of the active hydrogen-reactive compound is 0.01
When the amount is less than part by weight, the reactivity between the active hydrogen-reactive compound and the active hydrogen functional group is remarkably reduced.
Exceeding 0 parts by weight is not preferred because effects such as improvement in moisture permeability and anti-blocking are leveled off and unreacted active hydrogen-reactive compounds are precipitated.

A moisture-proof paint (water-based) by mixing the above materials
At this time, if necessary, a dispersant such as a polycarboxylic acid, an antifoaming agent, a surfactant, and a color adjusting agent can be added. This paint is applied to a paper support by a conventional method to form a moisture-proof layer. The coating equipment is not particularly limited, but a coating method of scraping the coating surface such as a blade coater, a bar coater, or an air knife coater is preferable because it tends to promote the orientation of the tabular pigment.
When the coating amount of the moisture-proof layer is applied on one side (when applied on both sides, the coating amount of both sides is combined), the solid content is 15 to 4
0 g / m ^2, preferably 20 to 35 g / m ^2.

The paper support 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. Unbleached kraft paper (acid paper or neutral paper) is preferred. The basis weight of the paper support is 50 to 150 g
/ M ² , preferably 60 to 135 g / m ² . The thickness of the paper support is 70 to 170 μm, preferably 75 to 165
μm.

The moisture permeability of the moisture-proof paper of the present invention is JISZ020
8 as measured by the cup method (B method) 20~50g / m ² · ²
4 hr, preferably 25 to 45 g / m ² · 24 hr.

Hereinafter, the present invention will be described specifically with reference to Examples. Unless otherwise specified, “parts” and “%” represent “parts by weight” and “% by weight”, respectively.

[0023]

<Example 1> To 50 parts by weight of water, 3 parts by weight of polyoxyethylene phenyl ether (the number of moles of ethylene oxide was 5) was added, and the mixture was stirred.
100 parts by weight of SBR (solid content 50%) at 20 ° C. is added and stirred. Further, a phyllosilicate compound mica AB32
(Mica, average particle diameter 20 μm, aspect ratio 20-3
0: 50 parts by weight (manufactured by Mika Yamaguchi Co., Ltd.) were added while stirring, and the moisture-proof paint was prepared by using bleached kraft paper (basis weight 70
g / m ² , thickness 100 μm) as solids, 30 g per side
/ M ² , and dried at 110 ° C. for 1 minute using a hot-air drier to produce a moisture-proof paper.

Example 2 50 parts by weight of water, 2 parts by weight of 25% ammonia water, and 0.5 part by weight of a coupling agent KBM603 (aminosilane coupling agent: manufactured by Shin-Etsu Chemical Co., Ltd., active ingredient: 99% or more) 3 parts by weight of polyoxyethylene phenyl ether (the number of moles of ethylene oxide is 5), a gel fraction of 92%, and a Tg of 20 ° C.
100 parts by weight of SBR (solid content: 50%), phyllosilicate compound KF1325 (sericite, average particle size 13 μm)
m, aspect ratio 20-30: manufactured by Chuo Kaolin Co., Ltd.) 5
0 parts by weight were sequentially added with stirring to prepare a moisture-proof coating, which was then bleached to kraft paper (basis weight 70 g / m ² , thickness 100 μm).
m), a solid content of 30 g / m ^{2 was} applied on one side, followed by drying at 110 ° C. for 1 minute using a hot air drier to produce a moisture-proof paper.

Example 3 A moisture-proof paper was produced in the same manner as in Example 2 except that the amount of polyoxyethylene phenyl ether was changed to 1 part by weight. Example 4 A moisture-proof paper was produced in the same manner as in Example 2, except that the amount of polyoxyethylene phenyl ether was changed to 5 parts by weight. Example 5 A moisture-proof paper was manufactured in the same manner as in Example 2, except that the amount of polyoxyethylene phenyl ether was changed to 10 parts by weight.

<Examples 6 to 12> Moisture-proof papers were produced in the same manner as in Example 2 except that the following ether-based / polyether-based compounds were used instead of polyoxyethylene phenyl ether. Example 6: 2-butoxyethanol> Example 7: Polyoxyethylene nonyl ether (the number of moles of ethylene oxide is 7) Example 8: Polyoxyethylene benzyl alcohol ether (the number of moles of ethylene oxide is 2) Example 9: Polyoxy Example 10: Polyoxyethylene nonyl phenyl ether (the number of moles of ethylene oxide is 20) Example 11: Polyoxyethylene nonyl phenyl ether (the number of moles of ethylene oxide is 30) 12: polyoxyethylene decyl phenyl ether (the number of moles of ethylene oxide is 7)

<Examples 13 to 16> A moisture-proof paper was manufactured in the same manner as in Example 2 except that the following synthetic resin was used instead of the synthetic resin used in Example 2. Example 13: SBR (gel fraction 96%, Tg
Example 14: SBR (gel fraction 96%, Tg)
Example 15: Acrylic styrene (gel fraction 94%, Tg)
Example 16: NBR (gel fraction 91%, Tg)
(15 ° C, solid content 48%)

<Examples 17 to 20> Coupling agent KB
A moisture-proof paper was produced in the same manner as in Example 2, except that the following coupling agent was used instead of M603. Example 17: Epoxysilane coupling agent (trade name:
(Example: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) Example 18: Vinyl silane coupling agent (trade name: K
BM1003, manufactured by Shin-Etsu Chemical Co., Ltd.) Example 19: Methacryloxysilane coupling agent (trade name: KBM503, manufactured by Shin-Etsu Chemical Co., Ltd.) Example 20: amino titanate coupling agent (trade name: KR44, Ajinomoto (Made by Corporation)

<Example 21> 2 parts by weight of 25% aqueous ammonia in 50 parts by weight of water, and 0.5 part by weight of a coupling agent KBM603 (aminosilane coupling agent: manufactured by Shin-Etsu Chemical Co., Ltd., active ingredient: 99% or more) After stirring, 1 part by weight of the active hydrogen reactive compound SR302 (polyamide polyurea resin, solid content 60%, manufactured by Sumitomo Chemical Co., Ltd.) and polyoxyethylene phenyl ether (the number of moles of ethylene oxide is 5) are added. 3 parts by weight, gel fraction 92%, Tg20
100 parts by weight of SBR at 50 ° C. (solid content 50%), phyllosilicate compound KF1325 (sericite, average particle diameter 13 μm)
m, aspect ratio 20-30: manufactured by Chuo Kaolin Co., Ltd.) 5
0 parts by weight were sequentially added with stirring to prepare a moisture-proof coating, which was then bleached to kraft paper (basis weight 70 g / m ² , thickness 100 μm).
m), a solid content of 30 g / m ^{2 was} applied on one side, followed by drying at 110 ° C. for 1 minute using a hot air drier to produce a moisture-proof paper.

Example 22 Active hydrogen reactive compound SR
A moisture-proof paper was produced in the same manner as in Example 22 except that X-13A (polyamine resin, solid content: 99% or more, Sanwa Chemical Co., Ltd.) was used instead of 302.

Comparative Example 1 A moisture-proof paper was manufactured in the same manner as in Example 2 except that polyoxyethylene phenyl ether was not used. <Comparative Example 2> A moisture-proof paper was manufactured in the same manner as in Example 2 except that polyoxyethylene nonylphenyl ether (the number of moles of ethylene oxide was 60) was used instead of polyoxyethylene phenyl ether.

Comparative Example 3 A moisture-proof paper was manufactured in the same manner as in Example 2 except that SBR (solid content: 50%, manufactured by Zeon Corporation) having a gel fraction of 80% and a Tg of 5 ° C. was used. <Comparative Example 4> SBR of gel fraction 100%, Tg-13 ° C
A moisture-proof paper was manufactured in the same manner as in Example 2 except that the solid content was 48% (manufactured by Mitsui Toatsu Chemicals, Inc.).

<Comparative Examples 5 to 7> A moisture-proof paper was produced in the same manner as in Example 2 except that the following pigment was used instead of KF1325 as the phyllosilicate compound. Comparative Example 5: Mica B72 (muscovite, average particle size 82 μm
m, aspect ratio 20-30: manufactured by Mica Yamaguchi Co., Ltd. Comparative Example 6: UW-90 (muscovite, average particle size 1.5 μm)
Comparative Example 7: Microace P-3 (talc, average particle diameter 1.8 μm, aspect ratio 5 to 10: Nippon Talc Co., Ltd.)
Made)

<Test Method> 1) Moisture Permeability According to JIS Z0208 B method (cup method), the coated surface of each of the measurement sample which is folded in four (fold) and the one which is not formed (flat plate) is coated. On the outside, the moisture permeability was measured at 40 ° C. and 90% (relative humidity). The moisture permeability at 40 ° C and 90% is 50
g / m ² · 24 hr or less, more preferably 45 g / m ² · 24 hr
Below, 120 g / m ² · 24 hr or less, more preferably 100 g / m ² · 24 hr or less with creases, is sufficiently practical. 2) Disintegration test Using a TAPPI standard disintegrator, 45 g of moisture-proof paper of about 3 cm square was stirred with 1500 ml of water for 10 minutes.
A hand-made sheet having a basis weight of 70 g / m ² was prepared from the obtained pulp slurry. The size of disintegrated pieces of undisintegrated material is 1 mm x 1
mm or less were rated as 、, and those with disintegrated fragments exceeding the size were rated as x.

The measurement results of the above Examples and Comparative Examples are shown in Tables 1 to 3.
Shown in

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

From Table 1, it can be seen that the blending of the ether-based / polyether-based compound greatly improves the moisture-proof properties when creased (Examples 1 to 12). However, when the compound was not added (Comparative Example 1), the moisture-proof property of the fold was obtained. When the number of oxygen atoms forming the ether bond of the compound to be added was 30 or more (Comparative Example 2), the moisture-proof property of the flat plate was improved. , Respectively. From Table 2, it can be seen that the use of a high gel type synthetic resin (gel fraction of 90% or more) greatly improves the disintegration of coated paper (Example 2,
Examples 13 to 16). However, the gel fraction of the synthetic resin used is 90% or less, or the glass transition temperature (Tg) is -1.
When the temperature is outside the range of 0 to 40 ° C. (Comparative Examples 3 and 4), satisfactory disintegration cannot be obtained. From Table 3, when the phyllosilicate compound having a high aspect ratio is used alone or in combination with the coupling agent (Example 1, Examples 17 to 20)
Has good moisture-proof properties, but when the average particle diameter of the phyllosilicate compound used is 50 μm or more (Comparative Example 5) or 5 μm or less (Comparative Examples 6 and 7), satisfactory moisture-proof properties are obtained. I can't. The addition of the active hydrogen-reactive compound significantly improves the moisture resistance of the flat plate (Examples 21 to 22).

The easily disintegrating moisture-proof paper according to the present invention has excellent moisture-proof properties even when it is creased.

Claims (4)

[Claims] 1. A moisture-proof paper having a moisture-proof layer comprising a phyllosilicate compound and a synthetic resin on at least one surface of a paper support, wherein the synthetic resin has a gel fraction of 90% or more and a glass transition temperature of -10 ° C. or more. 40 ° C., wherein the moisture-proof layer contains at least one or more hydroxyl groups, or contains at least one or more hydroxyl groups, and the number of oxygen atoms forming an ether bond is in the range of 2 to 30. An easily disintegrating moisture-proof paper comprising the polyether compound according to claim 1. 2. The easily disintegrating moisture-proof paper according to claim 1, wherein the phyllosilicate compound is treated with a coupling agent. 3. The easily disintegrating moisture-proof paper according to claim 1, wherein the synthetic resin is a styrene-butadiene copolymer. 4. The easily disintegrating moisture-proof paper according to claim 1, wherein the moisture-proof layer contains an active hydrogen reactive compound.