JPH11286895A - Readily defibrable moistureproof paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain readily defiberable moistureproof paper excellent in defibrability in water and having sufficient water resistance even in folded state of moistureproof paper or under environment of 100% relative humidity. SOLUTION: In this moistureproof paper having a moistureproof layer comprising a phyllosilicate compound and a synthetic resin on at least one side of a paper support, the synthetic resin used has >=90% gel fraction and -10 deg.C to 40 deg.C glass transition temperature and a nonionic surfactant and a quaternary ammonium salt are contained in the moistureproof layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture-proof paper having excellent disintegration properties and having sufficient moisture-proof properties even in a creased condition or a condition of 100% relative humidity (including dew condensation). It is.

[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) a plate-like phyllosilicate compound particle having an average particle diameter of 5 to 50 μm and an aspect ratio of 5 or more, and (c) a moisture-proof improving agent was previously proposed (Japanese Patent Application Hei 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. Therefore, the present inventors have further examined that the gel fraction of the synthetic resin used is 90%.
% Or more, it was found that even a device having a weak defibrating force such as a pulper can be charged and separated. This is because, when the gel fraction of the synthetic resin is 90% or more, the dried film after the application of the moisture-proof layer can suppress molecular motion due to heat during drying,
It is presumed that the entanglement of the molecules between the particles of the synthetic resin is weakened, and the particles are weakly fused to each other. Therefore, it is considered that the elongation of the moisture-proof layer coating is reduced and the disintegration is improved. However, such a moisture barrier is poorly plastic,
Since it is expected that there are many voids between particles, if the moisture-proof layer is damaged by creases in the moisture-proof paper, or if it is placed in an environment with a relative humidity of 100%, the original moisture-proof property is significantly impaired. The problem that it ends up arises.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides an excellent disintegration and creased state or a relative humidity of 100%.
The present invention provides a moisture-proof paper having a sufficient moisture-proof property even in a high-humidity environment or in a state where condensation forms on the surface.

[0007]

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, wherein the moisture-proof layer contains a nonionic surfactant having an addition mole number of alkylene oxide in the range of 2 to 30 and a quaternary ammonium salt. It is.

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.

[0009]

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.

[0010] Of these phyllosilicate compounds, muscovite or sericite is preferred in view of the particle size, aspect ratio and the like. In the present invention, a more preferable average particle diameter (measured value by a laser diffraction method) range is 1 μm to 100 μm, and a more preferable average particle diameter range is 5 μm to 50 μm. Average particle size is 5μ
m or less, it is difficult for the orientation of the tabular pigment in the coating layer to be parallel to the support, and when it is 50 μm or more, part of the tabular pigment protrudes from the coating layer or the thickness of the tabular pigment. Is about several μm, the number of layers in the coating layer of the oriented flat pigment 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 fraction, 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 -5C.
~ 35 ° C. If the Tg is lower than -10 ° C, the disintegration becomes poor and blocking tends to occur. Also, Tg
Is higher than 40 ° C., the moisture-proof property deteriorates. Also,
The mixing ratio (solid weight) of the phyllosilicate compound and the styrene-butadiene latex used in the present invention is 3
0: 70-70: 30, preferably 35: 65-60:
40.

In the present invention, nonionic particles are formed to selectively fill the voids formed when the emulsion particles are dried / coated to impart plasticity to the moisture-proof layer and to increase the resistance to bending. A system surfactant can be used. The nonionic surfactant used at this time is a linear compound having at least one ether bond and a hydroxyl group in the main chain, such as a lauryl group, a cetyl group, a stearyl group, an octyl group, a nonyl group, a dinonyl group. Examples thereof include an alkyl alcohol having an alkyl group, an alkyl phenol, an alkyl amine, an alkyl amide, an alkyl ether compound, a glycerin compound, and a compound obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide to phenol, naphthol, benzyl alcohol, or the like. In the present invention, the number of moles of the alkylene oxide added to the nonionic surfactant is in the range of 2 to 30, and 2 to 15 is preferable. If the number of added moles exceeds 30, the hydrophilicity becomes too high, so that moisture resistance cannot be obtained after coating. Such compounds include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene phenyl ether, polyoxyethylene benzyl alcohol ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene β-naphthol ether, Polyoxyethylene bisphenol A ether, polyoxyethylene polypropylene glycol ether, polyoxyethylene alkylamino ether,
And polyoxyethylene rosin esters.

These nonionic surfactants are all hydrophilic, easily soluble in water, liquid at room temperature, and preferably have an aromatic ring. The amount of the compound is 0.1 to 10% by weight based on the total weight of the synthetic resin and the flat pigment.
Is most preferred. In this case, if the amount is less than 0.1% by weight, sufficient plasticity cannot be obtained, and the effect on bending is lost. If the content exceeds 10% by weight, not only does the effect on bending peak, but also the moisture-proof property is reduced.

Further, in the present invention, a quaternary ammonium salt can be used in order to more effectively fill the voids between particles. The quaternary ammonium salt forms a gel with the nonionic surfactant present in the interparticle space upon drying, and the interparticle space is more effectively filled by the hydrophobic groups of both compounds, Not only does resistance to bending improve,
It is considered that excellent moisture-proof properties are exhibited even in an environment with a relative humidity of 100%. The compound represented by the general formula (1) (R) 4NX (1) is usually used as the quaternary ammonium salt used at this time. In this case, R in the formula (1) represents the same or different alkyl groups such as methyl group, octyl group, lauryl group, cetyl group, stearyl group, nonyl group, and benzyl group. In the compound, two Rs may be mutually bonded to form a heterocyclic ring with N. X in the formula (1) represents an anion group, and is generally a halogen atom such as Cl or Br;
Acid groups such as a sulfonic acid group, an alkylsulfonic acid group, and a nitric acid group are exemplified. Such quaternary ammonium salts include, for example, alkyltrimethylammonium salt, alkyldimethylethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, alkylpyridinium salt, alkylpicolinium salt, alkylquinolinium salt, and alkylquinolinium salt. Imidazolinium salts, alkylamidopropyldimethylbenzylammonium salts and the like. In addition, a cationic polymer electrolyte such as polyvinylbenzyltrimethylammonium salt, polydimethyldiallylammonium salt, styreneacrylic acid triethylammonium salt, etc. may be used without any problem.

Among these quaternary ammonium salts, an alkyltrimethylammonium salt having an alkyl group having 6 to 18 carbon atoms, a dialkyldimethylammonium salt, an alkyldimethylbenzylammonium salt and the like are particularly preferably used in the present invention. . The compounding amount is 0.1% with respect to the total weight of the synthetic resin and the flat pigment.
~ 5% by weight is most preferred. In this case, the compounding amount is 0.1
When the amount is less than 5% by weight, a sufficient moisture-proofing effect cannot be obtained in an environment with a relative humidity of 100%. When the amount exceeds 5% by weight, the effect is not only leveled off, but also the moisture-proofing property 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, regarding 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 hydrophobized 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 and polymerize it (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). In the present invention, among these active hydrogen-reactive compounds, a polyamine compound, a polyamideamine resin, and the like are particularly preferably used from the viewpoints of environmental consideration and safety. The compounding amount is desirably 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight based on 100 parts by weight of the synthetic resin latex. When the amount of the active hydrogen-reactive compound is less than 0.01 part by weight, the reactivity between the active hydrogen-reactive compound and the active hydrogen functional group is remarkably reduced.
Exceeding the parts by weight is not preferred because effects such as an 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 easily disperses in water due to mechanical disaggregation action. 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
It is.

The moisture permeability of the moisture-proof paper of the present invention is JISZ020
20 to 50 g / m ² · 24 h measured by the 8 cup method (Method B)
r, 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.

[0026]

<Example 1> To 50 parts by weight of water, 2 parts by weight of polyoxyethylene phenyl ether (the number of moles of ethylene oxide added was 5) and 1 part by weight of lauryltrimethylammonium chloride were added, and the mixture was stirred. 100 parts by weight of SBR (solid content 50%) having a fraction of 92% and Tg of 20 ° C. are added and stirred. Further, 50 parts by weight of a phyllosilicate compound mica AB32 (muscovite, average particle size 20 μm, aspect ratio 20-30: manufactured by Yamaguchi Mica Kogyo Co., Ltd.) was added with stirring, and the moisture-proof coating was added to bleached kraft paper ( After applying 30 g / m ^{2 on} one side as a solid to a basis weight of 70 g / m ² and a thickness of 100 μm), it was dried at 110 ° C. for 80 seconds 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% aqueous ammonia, 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) Then, 2 parts by weight of polyoxyethylene phenyl ether (the number of moles of ethylene oxide added is 5), 1 part by weight of lauryltrimethylammonium chloride, a gel fraction of 92%, T
g 100 parts by weight of SBR (solid content 50%) at 20 ° C., phyllosilicate compound KF1325 (sericite, average particle diameter 13 μm, aspect ratio 20 to 30: Chuo Kaolin Co., Ltd.)
Moisture-proof paint prepared by sequentially adding 50 parts by weight of a water-proof kraft paper (basis weight 70 g / m ² , thickness 100
μm) as a solid content on one side of 30 g / m ² , and dried at 110 ° C. for 80 seconds 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 0.5 part by weight. <Example 4> 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 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 nonionic surfactant was used instead of polyoxyethylene phenyl ether. Example 6: Polyoxyethylene β-naphthol ether (additional mole number of ethylene oxide is 3) Example 7: polyoxyethylene nonyl ether (additional mole number of ethylene oxide is 7) Example 8: polyoxyethylene benzyl alcohol ether ( The number of moles of ethylene oxide added is 2) Example 9: Polyoxyethylene octyl phenyl ether (the number of moles of ethylene oxide added is 7) Example 10: The polyoxyethylene octyl phenyl ether (the number of moles of added ethylene oxide is 20) Example 11: polyoxyethylene octyl phenyl ether (the number of moles of added ethylene oxide is 30)

Example 12 A moisture-proof paper was manufactured in the same manner as in Example 2 except that the amount of lauryltrimethylammonium chloride was changed to 0.3 parts by weight. <Example 13> Example 2 except that the amount of lauryltrimethylammonium chloride was changed to 5 parts by weight.
A moisture-proof paper was manufactured in the same manner as described above.

<Examples 14 to 18> Moisture-proof papers were produced in the same manner as in Example 2 except that the following quaternary ammonium salts were used instead of lauryltrimethylammonium chloride. Example 14: Cetyltrimethylammonium chloride Example 15: Stearyltrimethylammonium bromide Example 16: Lauryldimethylbenzylammonium chloride Example 17: Laurylpicolinium chloride Example 18: 2-Dodecylisoquinolinium bromide

<Examples 19 to 22> Moisture proof papers were produced in the same manner as in Example 2 except that the following synthetic resins were used instead of the synthetic resins used in Example 2. Example 19: SBR (gel fraction 96%, Tg
Example 20: SBR (gel fraction 96%, Tg)
Example 21: Acrylic styrene (gel fraction 94%, Tg)
Example 22: NBR (gel fraction 91%, Tg)
(15 ° C, solid content 48%)

<Examples 23 to 26> 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 23: Epoxysilane coupling agent (trade name:
(Example: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) Example 24: Vinyl silane coupling agent (trade name: K
BM1003, manufactured by Shin-Etsu Chemical Co., Ltd.) Example 25: Methacryloxysilane coupling agent (trade name: KBM503, manufactured by Shin-Etsu Chemical Co., Ltd.) Example 26: amino titanate coupling agent (trade name: KR44, Ajinomoto (Made by Corporation)

Example 27 50 parts by weight of water, 2 parts by weight of 25% aqueous ammonia, 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 adding and stirring, 1 part by weight of the active hydrogen reactive compound PA625D (modified polyamine resin, solid content 55%, manufactured by Nippon PMC Co., Ltd.)
2 parts by weight of polyoxyethylene phenyl ether (the mole number of ethylene oxide is 5), 1 part by weight of lauryltrimethylammonium chloride, gel fraction 92%, Tg
100 parts by weight of SBR (solid content 50%) at 20 ° C., phyllosilicate compound KF1325 (sericite, average particle size 1
3 μm, aspect ratio 20-30: Chuo Kaolin Co., Ltd.
Moisture-proof paint prepared by sequentially adding 50 parts by weight of a water-proof kraft paper (basis weight 70 g / m ² , thickness 100
μm) as a solid content of 30 g / m ^{2 on} one side, followed by drying at 110 ° C. for 1 minute using a hot air drier to produce a moisture-proof paper.

Example 28 Active hydrogen reactive compound PA
A moisture-proof paper was manufactured 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 625D.

Comparative Example 1 A moisture-proof paper was manufactured in the same manner as in Example 2 except that polyoxyethylene phenyl ether and lauryltrimethylammonium chloride were not used. <Comparative Example 2> A moisture-proof paper was manufactured in the same manner as in Example 2 except that polyoxyethylene phenyl ether was not used. Comparative Example 3 A moisture-proof paper was produced in the same manner as in Example 2 except that lauryltrimethylammonium chloride was not used. <Comparative Example 4> 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 added was 60) was used instead of polyoxyethylene phenyl ether.

Comparative Example 5 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 6> 100% gel fraction, SBR at 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 7 to 9> Moisture-proof papers were produced in the same manner as in Example 2 except that the following pigment was used in place of KF1325 as the phyllosilicate compound. Comparative Example 7: Mica B72 (muscovite, average particle size 82 μm)
Comparative Example 8: UW-90 (Mica, average particle diameter 1.5 μm)
Comparative Example 9: 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 into four and creased (fold) and the one which is not attached (flat plate) is formed. Outside, 40 ℃ ・ 90% RH, 40 ℃ ・ 10
The moisture permeability was measured at 0% RH (measuring only the flat plate). 40
The moisture permeability at 90 ° C / 90% is 50g / m ² · 24hr on a flat plate
Or less, more preferably 45 g / m ² · 24 hr or less, creased 120 g / m ² · 24 hr or less, more preferably 100 g / m ²
m ² · 24 hr or less, 40 the moisture permeability ° C. · 100% RH is a flat 100g / m ² · 24hr or less, and more preferably is sufficiently practical when 80g / m ² · 24hr or less. 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 defibrated pieces of undisintegrated material is 1 mm x 1 m
m or less, and x when the disintegrated fragments exceeding the size remained.

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

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

[Table 4]

From Tables 1 and 2, it can be seen that the combined use of a nonionic surfactant and a quaternary ammonium salt significantly improves the moisture resistance when creased or at 100% relative humidity. Examples 2-18). However, when the compound was not added together (Comparative Example 1), or when only one of the compounds was added (Comparative Examples 2 and 3), either the creased or the moisture-proof property in an environment of 100% relative humidity was used. Or neither of them can achieve satisfactory performance. When the number of moles of ethylene oxide added to the added nonionic surfactant is 30 or more (Comparative Example 4), the moisture resistance of the flat plate decreases. From Table 3, 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 (Examples 2, 19 to 22). However, when the gel fraction of the synthetic resin used is 90% or less, or the glass transition temperature (Tg) is out of the range of -10 to 40 ° C (Comparative Examples 5 and 6), satisfactory disintegration is not obtained. . From Table 4, the phyllosilicate compound having a high aspect ratio was used alone,
Or when used in combination with a coupling agent (Example 1,
Examples 23 to 26) provide good moisture-proof properties, but are satisfactory when the phyllosilicate compound used has an average particle size of 50 μm or more (Comparative Example 7) or 5 μm or less (Comparative Examples 8 and 9). Good moisture resistance cannot be obtained. The addition of the active hydrogen-reactive compound further improves the moisture resistance of the flat plate (Examples 27 and 28).

[0046]

The easily disintegrating moisture-proof paper according to the present invention has excellent moisture-proof properties even in a creased state and in a high humidity environment with a relative humidity of 100%.

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 side 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 higher. An easily disintegrating moisture-proof paper, wherein the moisture-proof layer comprises a nonionic surfactant having a molar number of addition of alkylene oxide in the range of 2 to 30 and a quaternary ammonium salt. 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.