JP2002326329A - Dewing water collection sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dewing water collection sheet having improved moisture discharge properties and enhanced in repeated usability. SOLUTION: In the dewing water collection sheet having an air permeable sheetlike substrate and a water collection material provided on or in the substrate, the water collection material contains a water absorbable resin and a part or the whole of the water absorbable resin contains a poly-acidic amino acid or a salt thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for improving moisture release,
The present invention relates to a dew condensation sheet with improved usability. More specifically, it captures dew condensation water generated on container ceilings and container inner wall surfaces, wall surfaces of houses and other buildings, hollow layers in walls, steel columns and beams of steel-framed houses, water pipes, and the like. The present invention relates to a dew condensation sheet for preventing damage caused by dripping.

[0002]

2. Description of the Related Art In winter, when the temperature difference between the temperature and the temperature tends to occur, the indoor air is cooled by cold outside air, and dew may be formed on a container ceiling or a wall of a building. Such condensed water may cause so-called condensation damage, for example, in containers, which may fall on loaded cargo and corrode the cargo, and in buildings, may cause dew condensation on walls and cause stains and molds. Condensation in a hollow layer in a wall or the like may cause corrosion of a house structure.

[0003] Measures to prevent damage due to dew condensation include using an insulating material having an appropriate thickness, replacing independent heating with heating in all rooms, and discharging indoor water vapor by ventilation. It was difficult to apply to existing containers and houses. For this reason, as a simple preventive measure, means for preventing the damage by capturing the condensed water generated by a water catching material has been performed. I have.

Examples of such water-absorbent resins include starch / acrylate graft copolymers, vinyl alcohol / acrylate copolymers, polyacrylonitrile hydrolysates, cross-linked polyacrylate polymers, and modified polyvinyl alcohol. Polymers, acrylate polymers, acrylates
Acrylamide copolymer, isobutylene / maleic anhydride copolymer and the like are known.

[0005] However, these conventional water-condensing sheets using a water-absorbing resin do not have a sufficient moisture release rate, and it is difficult to evaporate the condensed water absorbed within the day. However, it was necessary to capture the dew water on the following day with the dew water captured on that day remaining on the sheet. For this reason, while repeating water capture and moisture release, the water capture capacity of the sheet is reduced, and there is a disadvantage that it is not possible to sufficiently capture the dew condensation water to the extent that it can be practically used. It has been desired to develop a dew condensation / water trap sheet having excellent moisture absorption and moisture release properties.

[0006]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a dew-condensation sheet that has improved moisture release characteristics of dew condensation water and improved reusability.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a water-permeable sheet-like substrate and water trapped on or in the substrate are provided. The water-absorbing material includes a water-absorbent resin, and a part or all of the water-absorbent resin is a water-absorbent resin containing a polyacid amino acid or a salt thereof. It has been found that the dew-condensation water-trapping sheet can improve the dehumidification characteristics of the dew-water and remarkably improve the repetitive usability, and have completed the present invention.

That is, the present invention relates to a water-permeable sheet-like substrate and a condensation water-absorbing sheet having a water-absorbing material on or in the substrate, wherein the water-absorbing material contains a water-absorbing resin. And a water-absorbing sheet, characterized in that a part or all of the water-absorbing resin is a water-absorbing resin containing a polyacid amino acid or a salt thereof.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, matters necessary for carrying out the present invention will be specifically described below.

In the present invention, the "condensation condensation sheet"
Paper or woven fabric that has enough strength not to be damaged by the weight of the water-absorbent resin swollen by capturing dew water,
A material having a structure in which a water catching material is disposed on or in a breathable sheet-like base material such as a nonwoven fabric or a synthetic resin. More specifically, for example, the air-permeable sheet-like base material and the water-absorbing material may be applied alone or impregnated with an adjusting solution dispersed in an organic solvent together with an optional binder.

The air-permeable sheet-like base material used in the dew / water collecting sheet of the present invention is not particularly limited as long as it is a base material having air-permeability. Specifically, JIS L-
The air permeability by the 1096 B method is preferably 10 seconds or less,
More preferably, a fibrous base material made from various base materials of 1 second or less is suitable. Among them, a sheet-like fibrous base material, that is, a fiber sheet is preferable, for example, a woven fabric, a nonwoven fabric,
Paper, knitted fabric and the like can be mentioned, but a nonwoven fabric made of various fiber webs is particularly preferably used for reasons such as strength.

In the present invention, the fiber constituting the air-permeable sheet-like substrate is not particularly limited,
General recycled fiber, semi-synthetic fiber, synthetic fiber, dietary fiber,
Animal fibers and the like can be used, but it is necessary to attract dew condensation water to the water catching material, and it is necessary to release absorbed dew condensation water. preferable. Such fibers include, for example,
Meta or para aromatic polyamide fiber, polyamide fiber, polyamide imide fiber, aromatic polyether amide fiber, polybenzimidazole fiber, acrylic fiber (including acrylic fiber having a large number of grooves on its surface), polyurethane fiber, polyclar fiber It is preferable to use vinylon fiber or the like. In addition, polyester fibers, polyolefin fibers such as polypropylene fibers, polyvinyl chloride fibers, vinylidene fibers, hydrophobic fibers such as benzoate fibers, those obtained by graft polymerization treatment of vinyl monomers, etc., those subjected to sulfonation treatment, and fluorine gas treatment Fibers which have been subjected to a hydrophilic treatment, such as those treated with a surfactant, those subjected to a discharge treatment, those treated with a hydrophilic resin and the like can also be used. Such fibers may be used alone or in combination of two or more.

The basis weight of the air-permeable sheet-like substrate in the present invention can be appropriately selected depending on the use of the obtained dew / water-absorbing sheet and the amount of the water-absorbing resin adhered to the substrate.
Generally preferred 7.5~500g / m ^2, more preferably in the range of 10 to 200 g / m ^2. The thickness is not particularly limited.

Further, the elongation percentage in the longitudinal direction and the lateral direction of the air-permeable sheet-like substrate is not particularly limited, but is defined by JIS.
L-1096 Elongation percentage by cut strip method is 50
% Or less is preferable.

As a method of combining the air-permeable sheet and the water-absorbing resin in the present invention, for example, only one sheet wraps a water-absorbing material having a moisture-absorbing property and a moisture-absorbing property (hereinafter referred to as "moisture-absorbing and releasing property"). Any method may be used without particular limitation, such as a method of integrating with a sheet, a method of sandwiching between two or more sheets, and a method of spraying a water catching material in multiple layers. or,
In view of the moisture release property of dew condensation water, a configuration in which the water-absorbing resin is dispersed in multiple layers is preferable in order to widen the gap between the particles.

The average particle size of the water-absorbing resin used in the dew / water collecting sheet of the present invention is not particularly limited, but is preferably in the range of 0.01 to 500 μm, more preferably 1 to 10 μm.
The range is 0μ.

The content of the water-absorbing resin used in the dew condensation / water catching sheet of the present invention is usually preferably 1% by weight or more, more preferably 50% by weight or less. If the content of the water-absorbing resin is in such a range, more excellent moisture-absorbing and releasing properties and shape retention can be obtained.

The water-absorbing dew sheet of the present invention is a water-absorbing material having the above-mentioned structure, wherein a water-absorbing resin containing a polyacid amino acid or a salt thereof is used as a part or all of the water-absorbing resin used. By using this, it is possible to provide a dew condensation water trap sheet, which is the object of the present invention, in which the moisture release property of dew condensation water is improved and the reusability is improved.

The polyacid amino acid used in the present invention is
There is no particular limitation on the water-absorbing resin containing the salt.
Specific examples include polyglutamic acid or a salt thereof, polylysine or a salt thereof, polyaspartic acid or a salt thereof, a glutamic acid copolymer or a salt thereof, and a water-absorbent resin obtained by crosslinking an aspartic acid copolymer or a salt thereof;
A water-absorbent resin for reacting a polysaccharide with an anhydrous polyacid amino acid having at least one ethylenically unsaturated bond in the molecule and reacting a crosslinking agent; by hydrolyzing a cross-linking reaction product of the anhydrous polyamino acid and the polysaccharide Water absorbent resin obtained by reacting polyamino acid and protein; water absorbent resin obtained by reacting anhydrous polyamino acid with protein; having at least one ethylenically unsaturated bond in the molecule An anhydrous polyacidic amino acid;
Water-absorbing resins obtained by reacting with an ethylenically unsaturated compound are exemplified.

In the present invention, the water-absorbent resin obtained by reacting the anhydrous polyacidic amino acid (A) having at least one ethylenically unsaturated bond in the molecule with the ethylenically unsaturated compound (B) is: The component (A), the component (B) and, if necessary, the polysaccharide (C) are obtained by a polymerization method using a known radical polymerization initiator in the presence of a crosslinking agent.

As the component (A) used in the present invention, as the anhydrous polyacidic amino acid having at least one ethylenically unsaturated bond in the molecule, a polysuccinimide having a maleimide terminal group as a terminal group can be used as it is. . For example, a polysuccinimide having a maleimide terminal group can be obtained by heat-reacting maleic anhydride, fumaric acid, malic acid, or the like with ammonia, followed by maleimide or maleamic acid. Further, the anhydrous polyacid amino acid (A) having at least one ethylenically unsaturated bond in the molecule includes an anhydrous polyacid amino acid;
A compound obtained by reacting a compound having a functional group having reactivity with an ethylenically unsaturated bond and an anhydrous polyacid amino acid in the molecule may be used.

The anhydrous polyacid amino acid referred to in the present invention may have a linear structure or a branched structure as long as it is an anhydride of polyaspartic acid or polyglutamic acid. Further, it may partially contain an amide bond. Further, the basic skeleton may contain a bond with an amino acid derivative other than glutamic acid and aspartic acid (that is, it may be a copolymer).
Examples of the amino acid derivatives other than glutamic acid and aspartic acid include, for example, aliphatic α such as glycine, alanine, valine, leucine, isoleucine, serine, threonine, asparagine, glutamine, lysine, ornithine, cystine, methionine, proline, hydroxyproline, and arginine. -Amino acids, tyrosine, phenylalanine,
Aromatic α-amino acids such as tryptophan and histidine;
Those in which the side chain functional groups of these α-amino acids have been substituted, β
-Aminocarboxylic acids such as -alanine and γ-aminobutyric acid; dipeptides (dimers) such as glycyl-glycine and aspartyl-phenylalanine; and tripeptides (trimers) such as glutathione. These amino acid derivatives may be optically active forms (L-form, D-form) or racemic forms.
In addition, these bonds may be present randomly (random copolymer) or may be present blockwise (block copolymer).

The method for producing the anhydrous polyacid amino acid is not particularly limited. For example, a method for producing D / L-aspartic acid by heat dehydration-condensation;
A method for producing D / L-aspartic acid by heat dehydration-condensation in the presence of a catalyst such as phosphoric acid; by subjecting D / L-aspartic acid to heat dehydration-condensation in an appropriate solvent in the presence of a catalyst such as phosphoric acid. Production method: Maleimide anhydride, fumaric acid, malic acid, etc. are heated and reacted with ammonia to produce maleimide or maleamic acid, followed by maleimide anhydride, fumaric acid, malic acid, etc., and ammonia are reacted with ammonia to produce maleimide, or There is a method of producing maleamic acid and producing it in the presence of a catalyst such as phosphoric acid.

In the molecule used in the present invention, at least one
The molecular weight of the anhydrous polyacid amino acid (A) having two ethylenically unsaturated bonds is preferably 50 by weight average molecular weight.
0 or more, more preferably 1000 or more. When the weight-average molecular weight is 500 or more, a water-absorbent resin, which is the object of the present invention, can be obtained, in which the dew-absorbed water that has absorbed water has a sufficiently high level of quick release of moisture under dry humidity.

Specific examples of the compound having a functional group reactive with an ethylenically unsaturated bond and an anhydrous polyacidic amino acid in the molecule include, for example, glycidyl acrylate,
Glycidyl methacrylate, acrylic acid, methacrylic acid, 2-methacryloyloxyethyl isocyanate, 2-isocyanatomethyl acrylate and the like can be mentioned.

The method for reacting the above-mentioned anhydrous polyacid amino acid with a compound having a functional group having an ethylenically unsaturated bond and a reactivity with the anhydrous polyacid amino acid in the molecule is as follows. A method in which a compound having a functional group reactive with an ethylenically unsaturated bond and an anhydrous polyacidic amino acid is directly added and mixed; a powder of an anhydrous polyacidic amino acid is dispersed in an inert solvent, and the ethylenic acid is added to the dispersion in the molecule. A method of adding and mixing a compound having a functional group reactive with an unsaturated bond and an anhydrous polyacidic amino acid; Dissolve in aprotic organic solvents such as imidazolinone, dimethyl sulfoxide, sulfolane, etc. A method of adding and mixing a compound having a functional group having a reactivity with an unsaturated bond and an anhydrous polyacid amino acid; hydrolyzing by adding an aqueous alkali solution to the anhydrous polyacid amino acid; Alternatively, a method of adding and mixing a compound having a functional group reactive with a hydrolyzate of an anhydrous polyacid amino acid; once hydrolyzing by adding an aqueous alkali solution to the anhydrous polyacid amino acid, adding an acid to the obtained aqueous solution. After neutralizing the hydrolyzate of the anhydrous polyacid amino acid by adding thereto, an anhydrous polyacid amino acid or a compound having a functional group reactive with the hydrolyzate of the anhydrous polyacid amino acid is added to the obtained aqueous solution and mixed. Method.

The amount of the compound having a functional group reactive with an ethylenically unsaturated bond and an anhydrous polyacidic amino acid in the molecule is preferably 0.1 to 1 mol of the anhydrous polyacidic amino acid. It is in the range of 8 to 3 mol, more preferably in the range of 0.9 to 2 mol. If the amount of the compound having a functional group reactive with an ethylenically unsaturated bond and an anhydrous polyacid amino acid in the molecule is within the above range, the amount of unreacted substances can be reduced, and Improve the performance of water-absorbent resin obtained by using the reaction product of a compound having a functional group reactive with ethylenically unsaturated bond and anhydrous polyacid amino acid and anhydrous polyacid amino acid for radical polymerization It is preferable because it can be performed.

In the present invention, the reaction temperature between an anhydrous polyacid amino acid and a compound having a functional group reactive with an ethylenically unsaturated bond and an anhydrous polyacid amino acid in the molecule is as follows:
Although not particularly limited, it is preferably in the range of 20 to 150 ° C.

The component (A) used in the present invention, which is an anhydrous polyacidic amino acid having at least one ethylenically unsaturated bond in the molecule, is preferably hydrolyzed before it is used for radical polymerization. The hydrolysis reaction at this time is performed under alkaline conditions, for example, by adding an aqueous alkali solution, and the reaction temperature is preferably 0 to 100.
° C, more preferably in the range of 20 to 95 ° C, and the reaction time is not particularly limited, but is generally 0.1 to 2 hours.

The alkali used in the hydrolysis reaction
As metal compounds and / or alkaline earth metal compounds
Is preferably a hydroxide or carbonate, for example, Li
OH, NaOH, KOH, Mg (OH)_{Two ,}Ca (OH)
_{Two ,}Li_TwoCO_Three, Na_TwoCO_Three, K _TwoCO_Three, MgCO_{Three ,}Ca
CO_ThreeEtc., among which sodium hydroxide or
Of using a 0.1 to 40% by weight aqueous solution of potassium hydroxide.
Is common.

The amount of the alkali added in the hydrolysis reaction is preferably in the range of 0.4 to 1.0 mol based on 1 imide ring group.

In the present invention, at least one
The anhydrous polyacid amino acid (A) having two ethylenically unsaturated bonds may be neutralized with a protonic acid such as hydrochloric acid, sulfuric acid, phosphoric acid or the like for the purpose of adjusting pH after being hydrolyzed in advance. By adjusting the pH, the ethylenically unsaturated bond and the ethylenically unsaturated bond in the molecule generated during the reaction between the anhydrous polyacidic amino acid and the compound having a functional group having reactivity with the anhydrous polyacidic amino acid and the molecule. Hydrolysis of the ester portion of the compound having a functional group reactive with the anhydrous polyacid amino acid can be prevented.

The ethylenically unsaturated compound (B) used in the present invention is preferably a water-soluble ethylenically unsaturated compound, and any water-soluble or water-miscible compound can be used. Can also be used. Examples of the water-soluble ethylenically unsaturated compound include (meth) acrylic acid and / or its alkali metal salt, alkaline earth metal salt, ammonium salt, 2- (meth) acrylamide-2-methylsulfonic acid and / or Ionic compounds such as alkali metal salts; non-ionic compounds such as (meth) acrylamide, N, N-dimethylacrylamide, 2-hydroxyethyl (meth) acrylate, N-methylol (meth) acrylamide; diethylaminoethyl (meth) acrylate Dimethylaminopropyl (meth) acrylate and the like, and amino group-containing unsaturated compounds and quaternized compounds thereof. One or more selected from these groups can be used. Here, the term "(meth) acryl" means both "acryl" and "methacryl". Among these, (meth) acrylic acid and / or its alkali metal salt, alkaline earth metal salt, ammonium salt, (meth)
Acrylamide is mentioned. Examples of the alkali metal salt include a sodium salt, a potassium salt, a lithium salt, a rubidium salt and the like, and among them, a sodium salt and a potassium salt are preferable.

The polysaccharide (C) used in the present invention includes, for example, starch, cellulose, alginic acid and the like. The starch generally includes starch composed of natural or plant-derived amylose and / or amylopectin, starch-containing substances, and modified products thereof. More specifically, potato starch, onion starch, wheat starch, tapioca starch, rice starch, sweet potato starch, sago starch, waxy starch, high amylose corn, flour, rice flour, and the like. Further, as modified starch, monomers obtained by graft copolymerization of starch with monomers such as acrylates, methacrylates, olefins, styrene, etc., and those reacted with fatty acids, and dextrinization, oxidation, and acid treatment of these. , Pregelatinized, etherified, esterified and crosslinked. Further, structurally modified starch (EP032) obtained by heating starch containing water to a temperature higher than its glass transition temperature and melting temperature.
7505A2). Further, polysaccharides such as guar gum, chitin, cellulose, alginic acid, and agar can also be used. Examples of the cellulose include cellulose obtained from wood, leaves, stems, ginseng, seed hair, and the like; processed cellulose such as alkyl etherified cellulose, organic acid esterified cellulose, carboxylated cellulose, oxidized cellulose, and hydroxyalkyl etherified cellulose. Is mentioned.

When the polysaccharide (C) is used, it is preferable that the polysaccharide (C) is dissolved or swelled and dispersed in the system before the reaction.

The reaction method in the present invention may be carried out in an aqueous solution, a solvent, or a suspension, and can be carried out by a known radical polymerization method. That is,
The method of mixing the anhydrous polyacidic amino acid (A) having at least one ethylenically unsaturated bond in the molecule and the ethylenically unsaturated compound (B) is a method in which both are charged into a reactor at once from the beginning. Any method such as a method of starting one of the reactions first and then dropping the other can be employed, and is not particularly limited in the present invention.

The amount of the ethylenically unsaturated compound (B) relative to the anhydrous polyacidic amino acid (A) having at least one ethylenically unsaturated bond in the molecule is preferably 0.1 / 1 to 100/1 by weight. , More preferably 1/1
５０50/1 weight ratio. When the amount of the ethylenically unsaturated compound used is within such a range, a water-absorbing resin having excellent water absorption and a high moisture release rate can be obtained.

As the crosslinking agent used in the above radical polymerization method, a polyfunctional ethylenically unsaturated compound having two or more polymerizable unsaturated groups or a compound having two or more reactive groups is used. Used as As the polyfunctional ethylenically unsaturated compound, basically any compound can be used as long as it is an ethylenically unsaturated compound having two or more ethylenically unsaturated groups. For example, N, N'- Methylenebis (meth) acrylamide, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth) acrylate,
Glycerin tri (meth) acrylate, glycerin acrylate methacrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, triallyl cyanurate, triallyl isocyanurate , Triallyl phosphate, triallylamine, poly (meth)
Allyloxyalkane, (poly) ethylene glycol diglycidyl ether, glycerol diglycidyl ether, ethylene glycol, polyethylene glycol, propylene glycol, glycerin, pentaerythritol, ethylenediamine, polyethyleneimine, glycidyl (meth) acrylate and the like can be mentioned.

Examples of the crosslinking agent having two or more reactive groups include, for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, polyglycerin, propylene glycol, 1,4-butanediol, Polyhydric alcohols such as 5-pentanediol, 1,6-hexanediol, neopentyl alcohol, diethanolamine, tridiethanolamine, polypropylene glycol, polyvinyl alcohol, pentaerythritol, sorbit, sorbitan, glucose, mannitol, mannitol, sucrose, glucose, etc. Polyglycidyl ethers such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and glycerin triglycidyl ether; Hydrin, alpha-haloepoxy compound methyl chlorohydrin, and the like; glutaraldehyde, polyaldehydes such as glyoxal; polyamines such as ethylenediamine; calcium hydroxide, calcium chloride,
Hydroxides, halides, carbonates, oxides of metals of Groups 2A, 3B and 8 of the periodic table such as calcium carbonate, calcium oxide, magnesium borax, magnesium oxide, aluminum chloride, zinc chloride and nickel chloride; Borates such as borax; polyvalent metal compounds such as aluminum isopropylate; One or more of these can be used in consideration of reactivity, but it is more preferable to use a polyfunctional ethylenically unsaturated compound having two or more ethylenically unsaturated groups in one molecule.

The amount of the crosslinking agent to be used is preferably 0.005 to 2 with respect to the ethylenically unsaturated compound (B).
Mol%, more preferably in the range of 0.01 to 1 mol%.

In the present invention, for example,
The reversed-phase suspension polymerization method exemplified in 2753408 can be used. When the reverse phase suspension polymerization method is used, an anhydrous polyacidic amino acid (A) having at least one ethylenically unsaturated bond in a molecule and an ethylenically unsaturated compound (B)
Of reverse-phase suspension polymerization using a radical initiator in the presence of a cross-linking agent in a hydrophobic solvent containing a W / O type surfactant in the presence of a W / O type surfactant; In a hydrophobic solvent where a surfactant was present, in the presence of a crosslinking agent,
A method of initiating reverse-phase suspension polymerization using a radical initiator, followed by dropwise addition of an aqueous solution of an anhydrous polyacidic amino acid (A) to further carry out reverse-phase suspension polymerization; The first-stage reverse-phase suspension polymerization is performed using a radical polymerization initiator in a hydrophobic solvent having a surfactant using an O-type surfactant in the presence of a cross-linking agent. A reverse aqueous suspension polymerization is carried out by adding a mixed aqueous solution of an anhydrous polyacidic amino acid (A) having at least one ethylenically unsaturated bond in the molecule and an ethylenically unsaturated compound (B) to the polymerization reaction system after the polymerization. Any method, such as the method of performing the above, can be appropriately selected.

The W / O type surfactant used in the present invention may be any one which is soluble in a hydrophobic solvent and can basically form a W / O type dispersion. Such a surfactant is generally HLB (Hydrophile-Lipophile-Bal
ance) is preferably in the range of 1 to 9, more preferably 2 to 7 nonionic and / or anionic. Specific examples of the surfactant include sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, sucrose fatty acid ester, polyglycerin fatty acid ester, polyoxyethylene alkylphenyl ether, ethylcellulose, ethylhydroxyethylcellulose, polyethylene oxide, and anhydrous maleated polyethylene. And maleic anhydride polybutadiene, maleic anhydride ethylene-propylene-diene terpolymer, a copolymer of α-olefin and maleic anhydride or a derivative thereof polyoxyethylene alkyl ether phosphoric acid, and the like. These surfactants can be used in combination of two or more as appropriate.

The amount of the surfactant used is preferably in the range of 0.05 to 10% by weight, more preferably 0.1 to 1% by weight, based on the hydrophobic solvent.

Examples of the radical polymerization initiator used in the production of the water-absorbent resin used in the dew-water collecting sheet of the present invention include inorganic peroxides (hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate). etc),
Organic peroxides (benzoyl peroxide, di-t-butyl peroxide, cumene hydroxy peroxide, succinic peroxide, di (2-ethoxyethyl) peroxy dicarbonate, etc.), azo compounds (azobisisobutylnitrile, azobiscyano) Valeric acid, 2,2′-azobis (2-amidinopropane) hydrochloride, etc.) and a redox catalyst (reducing agents such as alkali metal sulfites or bisulfites, ammonium sulfite, ammonium bisulfite, ascorbic acid and alkali metal) A combination of oxidizing agents such as persulfate, ammonium persulfate, and peroxide). These polymerization initiators may be used as a mixture.

The amount of the radical polymerization initiator used is usually preferably 0.0001 to 5% by weight, more preferably 0.0005 to 5% by weight based on the total amount of the ethylenically unsaturated compound (B) and the crosslinking agent. 1% by weight.

The inert solvent used in the production of the water-absorbent resin used in the dew-water collecting sheet of the present invention includes:
Basically, any material can be used as long as it is hardly soluble in water and inert to the polymerization reaction. As an example, n-
Aliphatic hydrocarbons such as pentane, n-hexane, n-heptane and n-octane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene; n-Hexane, n-heptane and cyclohexane are preferred.

Further, the water-absorbent resin used in the dew condensation / water trap sheet of the present invention can be crosslinked on the surface by setting an appropriate moisture content during drying. The surface cross-linking is carried out by azeotropic dehydration so that the water concentration in the water-containing polymer is 0.1 to 50% by weight based on the solid content of the polymer (if the water concentration of the water-containing polymer is within this range after polymerization, it is necessary to perform dehydration. Needless to say) and then a crosslinker is added to the dispersion of wet polymer particles adjusted to this particular moisture concentration,
If necessary, the addition can be carried out together with a catalyst.

As a method for drying the water-absorbent resin used in the dew condensation / water catching sheet of the present invention, for example, a vacuum drying method, a freeze drying method and the like can be appropriately selected.

The surface crosslinking agent used in the present invention includes:
For example, polyamines and polyglycidyl ethers such as 2
A compound having a reactive group capable of reacting with at least two carboxyl groups and / or carboxylate groups, and γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β (amino Ethyl) a silane coupling agent such as γ-aminopropyltrimethoxysilane and γ-mercaptopropyltrimethoxysilane together with dibutyltin dilaurate, dibutyltin diacetate, and dibutyltin dioctoate known as silanol condensation catalysts, if necessary. In addition to the above, an ethylenically unsaturated compound having a reactive group such as glycidyl methacrylate can be used together with a radical polymerization initiator, if necessary.

The amount of the surface cross-linking agent to be added varies depending on the amount of water and the like, but is usually preferably 0.001 to 10% by weight, more preferably 0.1 to 10% by weight, based on the solid content.
It is in the range of 01 to 3% by weight. By performing surface cross-linking within this range, the effect of improving the water absorption rate and gel strength can be obtained without excessively decreasing the water absorption capacity.

The water-absorbent resin containing a polyacid amino acid or a salt thereof used in the present invention is preferably subjected to a porous treatment.

The porosity treatment referred to herein may be any formula that gives porosity, and it may be N-type which decomposes or sublimates with generation of gas when drying the water-absorbent resin at 80 ° C. to 250 ° C. Containing blowing agent as an ethylenically unsaturated compound (B)
And a method of adding a carbonate blowing agent to the ethylenically unsaturated compound (B).

The water-absorbing material on or in the substrate in the present invention is a water-absorbing material having both a moisture absorbing property and a moisture releasing property.

The water condensation sheet of the present invention is characterized in that a water-absorbent resin containing a polyacid amino acid or a salt thereof is used as the water-absorbent resin used in the water-absorbing material. The water-absorbing resin containing a salt may be used by mixing with another water-absorbing resin that absorbs a large amount of water and swells.

In the present invention, the dew-condensation water-absorbing sheet may be obtained by arranging a fine powder of a water-absorbing resin containing a polyacid amino acid or a salt thereof on or in an air-permeable sheet-like substrate alone or optionally. And a control liquid dispersed in an organic solvent together with the binder described above is applied or impregnated to form a moisture absorbing / releasing layer. As the organic solvent used at this time, for example, toluene, xylene, cyclohexane, methyl ethyl ketone, ethyl acetate, tetrahydrofuran, dimethylformamide, methanol, ethanol, butanol or a mixture thereof can be used in an appropriate amount.

Examples of the binder include natural rubber and thermoplastic resins such as polychloroprene, acrylic rubber, butadiene synthetic rubber, polyisoprene, styrene-butadiene copolymer, styrene-isoprene copolymer, ethylene-vinyl acetate copolymer, and polyurethane resin. Synthetic rubber or polyacrylamide-polyvinyl alcohol emulsion, alkyl acrylate copolymer emulsion, alkyl acrylate-vinyl acetate copolymer emulsion, ethylene-vinyl acetate copolymer emulsion, polyvinyl acetate emulsion, polyvinyl alcohol, sodium carboxymethylcellulose Salt and the like can be mentioned, and among them, it can be appropriately selected in consideration of characteristics such as adhesion viscosity, toughness, workability and the like. These binders may be used alone or in combination of two or more,
Further, a thermoplastic resin having good compatibility with these binders (for example, polyethylene or the like) may be mixed and used.

The above-mentioned adjusting solution can be applied or impregnated on a gas-permeable sheet-like substrate by a conventionally known suitable means such as a brush, a spatula, a bar coder, a flow coater, a dip coater and the like. The amount to be applied or impregnated can be appropriately selected depending on various conditions such as the type, thickness, application, and compatibility of the water-absorbing resin and the solvent, of the air-permeable sheet-like substrate.

Further, on this moisture absorbing / releasing layer, for example,
Adhere an impermeable synthetic resin film or a breathable substrate,
Alternatively, a surface (referred to as a “back surface”) in which the water-absorbing resin layer is not substantially exposed to the surface layer is formed by applying a synthetic resin paint or a polyurethane paint capable of forming a ventilation layer.
This back surface may be made of an adhesive material, and may be provided with a release paper if necessary.

The dew condensation sheet of the present invention is liable to generate, for example, container ceilings and container inner walls, walls of houses and other buildings, hollow layers in walls, steel columns and beams of steel-framed houses, and water pipes. It can be used by constructing it at places. The construction method is not particularly limited, for example, a hot-melt system, a urethane system, a method of sticking a dew condensation sheet with various adhesives such as an emulsion system, a rubber system,
A method of applying various pressure-sensitive adhesives such as acrylic, emulsion, etc. to the dew condensation prevention sheet and sticking with the pressure-sensitive adhesive,
A method of attaching with a double-sided tape can be used. In addition, the method of constructing the dew condensation water trap sheet of the present invention is not limited to the above method.

The dew condensation sheet of the present invention may be mixed with, for example, fibers having antibacterial or antifungal properties as a component of the dew condensation sheet as long as the moisture absorption and desorption properties are not reduced. It is preferable to add an antibacterial agent or an antifungal agent to the resin. The antimicrobial agent and the fungicide may be included in the water-absorbent resin by adding the compound to the water-absorbent resin in advance and then applying the compound to a base material and performing polymerization.
Further, it may be added to the base material.

The antibacterial and antifungal agents used in the present invention include, for example, isophthalo, pyridine, organic chlorine,
Examples include antibacterial and antifungal agents such as organic sulfur-based, organic arsenic-based, and antibacterial metal ion-containing systems such as silver and copper.

In the dew condensation / water catching sheet of the present invention, various additives such as a deodorant and a flame retardant can be added in addition to the antibacterial agent and the fungicide. These additives can be added in advance when obtaining the dew condensation / water catching sheet, or the additives can be applied to the obtained sheet, and the adding method is not particularly limited.

The dew condensation / water trap sheet of the present invention may be mixed with colored or dyed fibers or the like to enhance the design.
The water absorbent resin used may be colored or dyed.

Examples of the use of the water condensation sheet of the present invention include a water condensation prevention sheet for containers, a water condensation tape for windows on buildings, a water condensation tape for windows, and a tape for preventing condensation on water pipes. Absorbent articles and the like. For example, in a case where the dew condensation / water trap sheet of the present invention is used for an absorber layer in an absorbent article having a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorber layer provided between the two sheets. Etc.

When the dew condensation / water catching sheet of the present invention is used for an absorbent layer of an absorbent article, the shape is not particularly limited, and examples thereof include a plate shape, a corrugated plate shape, a roll shape, and a tape shape. The size can be used in an appropriate size according to the application. For example, when it is attached to a window frame, the width is 30 to 50.
It may be used after being cut into a tape shape of mm.

The surface density and thickness of the non-woven fabric used for the dew condensation sheet of the present invention can be appropriately set depending on the place where the dew condensation sheet is used, and are not particularly limited. For example, in the case where the dew condensation water trap sheet of the present invention is cut into a tape shape and used by fixing it to the frame below the window,
The surface density is preferably in the range of 200 to 400 g / m ² , and more preferably in the range of 250 to 350 g / m ² .

Further, since the amount of dew water absorption can be adjusted by the thickness of the dew / water collecting sheet, there is no particular limitation when used for the above-mentioned applications, but usually it is preferably 1 to 5 mm.
And more preferably in the range of 2 to 4 mm.

When the dew / water collecting sheet of the present invention is used for the absorbent layer of the absorbent article, for example, if the shape is a plate,
As a single layer or a plurality of layers, layers of water-absorbing paper are stacked as necessary, a liquid-permeable top sheet or nonwoven fabric is arranged on these surfaces, and a liquid-impermeable back sheet is arranged on the back surface, It is also possible to finish the dew condensation water trap sheet by equipping it with a string, an adhesive tape for mounting, an adhesive sheet or the like so that it can be easily fixed to a window frame, a ceiling, a wall, or the like.
Liquid-permeable top sheet, liquid-impermeable back sheet,
Tape for attaching to strings and containers for strength
The material and type of the string and the like are not particularly limited, and known materials used in a conventional dew / water collecting sheet can be used.

The dew condensation sheet of the present invention is particularly excellent in repeated moisture absorption / desorption properties with respect to water. The moisture absorption / desorption property can be measured by a test of the moisture absorption and the moisture release. The dew condensation water trap sheet according to the present invention has a characteristic of repeatedly releasing moisture at a humidity of 90% under a humidity of 90%. Therefore, the dew condensation / water trap sheet of the present invention can be used for products requiring repeated moisture absorption / desorption properties, for example, a dew condensation prevention sheet for overseas shipping containers, a humidity adjustment sheet in the field of construction, a dew condensation prevention sheet in walls, windows It can be widely used for dew condensation and water trap tape.

As described above, the embodiment of the present invention relates to a water-permeable sheet-shaped substrate and a water-condensing water-absorbing sheet having a water-absorbing material on or in the substrate. The present invention relates to a dew / water absorbing sheet, characterized in that the material contains a water-absorbing resin, and a part or all of the water-absorbing resin is a water-absorbing resin containing a polyacid amino acid or a salt thereof.

According to another aspect of the present invention, a water-absorbent resin containing a polyacidic amino acid or a salt thereof comprises an anhydrous polyacidic amino acid (A) having at least one ethylenically unsaturated bond in the molecule. ) And the ethylenically unsaturated compound (B).

In another aspect of the present invention, a water-absorbent resin containing a polyacidic amino acid or a salt thereof comprises an anhydrous polyacidic amino acid (A) having at least one ethylenically unsaturated bond in the molecule. ), An ethylenically unsaturated compound (B), and a polysaccharide (C).

According to another aspect of the present invention, each of the above-described dew-and-water traps is characterized in that the water-absorbing material on or in the substrate is a water-absorbing material having both a moisture absorbing property and a moisture releasing property. It depends on the water sheet.

[0074]

The present invention will be described more specifically with reference to examples and comparative examples. In the following, all parts and percentages are by weight unless otherwise specified. In addition, various properties of the resin were measured by the following methods. Further, the present invention is not limited to these examples.

[Method of Measuring Water Absorption Ratio] A water absorbing member sample of about 0.1 was placed in a 220 mesh nylon net tea bag.
g, put it in a large excess of ion-exchanged water for 1 hour to absorb water, pull it up, drain it for 15 minutes, and measure the increased weight. The measurement was performed using the weight when a similar operation was performed using only the tea bag as a blank. Water absorption ratio W
(G / g) is the mass a (g) of the sample, the tea bag containing the sample is immersed for a predetermined time, the mass b (g) after draining,
A tea bag containing no sample was immersed for a predetermined time, and calculated from the mass c (g) after draining according to the following equation. Water absorption ratio W = (b−c−a) ÷ a

[Method of Measuring Moisture Absorption] 10 cm × 10 cm
After fixing the test piece on a glass plate using a double-sided tape, the sheet weight (W ₄₀ ) after being allowed to stand for 8 hours in an atmosphere at a temperature of 25 ° C. and a relative humidity of 40% was measured. The sheet mass (W ₉₀ ) after standing for 8 hours in an atmosphere at a temperature of 25 ° C. and a relative humidity of 90% was measured, and the moisture absorption was determined by the following equation. Moisture absorption (%) = (W ₉₀ −W ₄₀ ) ÷ A × 100 A: Content of water-absorbent resin (g) W ₉₀ : Sheet mass at 90% relative humidity (g) W ₄₀ : 40% relative humidity Sheet mass of (g)

[Method of Evaluating Water Capturing] 10 cm × 10 cm
The test piece was fixed on a glass plate using a double-sided tape, and then left standing in an atmosphere at a temperature of 25 ° C. and a relative humidity of 90% for 8 hours. Whether or not it was wet was evaluated by the degree of wetness, and it was defined as “water catching”.

[Method of measuring moisture release rate] 10 cm × 10 cm
After fixing the test piece on a glass plate using a double-sided tape, the sheet weight (D ₉₀ ) after being allowed to stand for 8 hours in an atmosphere at a temperature of 25 ° C. and a relative humidity of 90% was measured. The sheet mass (D ₄₀ ) after being allowed to stand for 8 hours in an atmosphere at 25 ° C. and a relative humidity of 40% was measured, and the moisture release rate was determined by the following equation. Moisture release rate (%) = (D ₉₀ −D ₄₀ ) ÷ A × 100 A: Content of water absorbent resin (g) D ₉₀ : Sheet mass at 90% relative humidity (g) D ₄₀ : 40% relative humidity Sheet mass in (g)

[Evaluation Method of Moisture Release Property] 10 cm × 10 cm
Is fixed on a glass plate using a double-sided tape, and then left for 8 hours in an atmosphere at a temperature of 25 ° C. and a relative humidity of 90%. Then, the sheet is left for 8 hours in an atmosphere of a temperature of 25 ° C. and a relative humidity of 40%. The sheet surface condition after the contact was touched with a hand, and whether or not the dew condensation water was released was evaluated based on the degree of wetness, and the result was defined as "wet release property".

[Evaluation Method of Repeated Moisture Release] The sheet surface after repeating the above-described tests of moisture absorbency and moisture release 6 and 12 times was evaluated by touching the sheet surface with a hand, and the “repeated moisture release property” was evaluated. "

Reference Example 1 Production Example of Polysuccinimide Maleic anhydride 96 was placed in a 1-L four-necked flask equipped with a stirrer, thermometer, reflux device, and nitrogen gas blowing device.
g and 50 g of ion-exchanged water. After heating to 55 ° C. to dissolve maleic anhydride, the mixture was cooled once to obtain a maleic anhydride slurry. The inside of the system was heated again, and when the temperature reached 55 ° C., 60.8 g of 28% aqueous ammonia was added.
Thereafter, the temperature in the system was raised to 80 ° C. After reacting for 3 hours, the obtained aqueous solution was dried to obtain a reaction intermediate. 2
100 g of the reaction intermediate and 10 g of 85% phosphoric acid were charged into an L eggplant flask, and the mixture was reacted for 4 hours under reduced pressure at an oil bath temperature of 200 ° C. using an evaporator. The obtained product was washed several times with water and methanol. As a result of measuring the obtained polysuccinimide by GPC, the weight average molecular weight was 3,000.

Reference Example 2 Production Method of Water Absorbent Resin 1 An aqueous solution in which 20.6 g of sodium hydroxide was dissolved in a 500 ml four-necked flask equipped with a stirrer, a thermometer, a reflux device, and a nitrogen gas blowing device. After adding 75g,
50 g of the polysuccinimide obtained in Reference Example 1 was added and stirred to obtain an aqueous solution of the polysuccinimide. Next, the temperature was raised to 90 ° C., 5.0 g of glycidyl methacrylate was added, and the reaction was carried out for 1 hour to obtain a polysuccinimide hydrolyzate aqueous solution into which a methacryl group was introduced. In a 100 ml Erlenmeyer flask, HLB = 16
Sucrose ester (DK ESTER F-
160) 0.75 g was weighed, 20 g of cyclohexane was added, and the mixture was heated to 50 ° C. and dispersed and dissolved. 7.8 g of the aqueous solution obtained by the above-described operation was added thereto, and the mixture was stirred to obtain a dispersion of an aqueous solution of a hydrolyzate of a polysuccinimide having a methacryl group introduced therein.

Separately, 164 g of cyclohexane was added to a 500 ml four-necked flask equipped with a stirrer, a thermometer, a reflux device, and a nitrogen gas blow-in device, and sucrose ester having HLB = 9 (DK ester F) was added thereto. -90)
0.75 g was added, and the mixture was heated to 50 ° C. with stirring to dissolve. Thereafter, the contents of the flask were cooled to 30 ° C. On the other hand, acrylic acid 30 was placed in a 500 ml Erlenmeyer flask.
g of sodium hydroxide while cooling externally.
92.8 g of an aqueous sodium hydroxide solution in which 3 g was dissolved was added dropwise to neutralize 80 mol% of acrylic acid. 9.8 mg of N, N'-methylenebisacrylamide was added to this solution, and 0.05 g of ammonium persulfate was further added and dissolved. Next, the 75 mol% partially neutralized acrylate aqueous solution containing a polymerization initiator and a cross-linking agent obtained as described above is added to the contents of the cylindrical round bottom flask, and a surfactant is added. The mixture was dispersed in a cyclohexane solution containing the mixture, and the inside of the system was sufficiently replaced with nitrogen. Thereafter, the temperature was raised by heating to start the polymerization reaction. After a while, heat generation was started, and 5 minutes after the heat generation reached a peak, the previously obtained dispersion solution of the aqueous solution of the hydrolyzate of polysuccinimide into which the methacryl group was introduced was added. Thereafter, the temperature was maintained at 60 to 65 ° C. for 3 hours.
The stirring was performed at 300 rpm. After completion of the reaction, the cyclohexane phase was separated from the gel product obtained by the above method by decantation, and then water was removed from the wet polymer by drying under reduced pressure. Thus, a spherical polymer powder was obtained. Table 1 shows the property evaluation results of the water absorbent resin 1 obtained here.

Reference Example 3 Method for Producing Water Absorbent Resin 2 10 g of the polysuccinimide obtained in Reference Example 1 was placed in a 500 ml four-necked flask equipped with a stirrer, thermometer, reflux device, and nitrogen gas blowing device. , And 20 g of N, N-dimethylformamide (DMF) were charged and dissolved at about 70 ° C., 1 g of glycidyl methacrylate was added, the reaction was continued for 30 minutes, and 3.3 g of sodium hydroxide was dissolved. 150 g of the resulting aqueous solution was added to hydrolyze the polysuccinimide. After cooling the system temperature to about 35 ° C., 1 g of pregelatinized starch (Alster B, manufactured by Nippon Shokuhin Kako Co., Ltd .; hereinafter, manufactured by the company), 25 g of acrylic acid,
Dipentaerythritol hexamethacrylate 0.2
5 g were charged. Next, the inside of the system was replaced with nitrogen, and 2,2-azobisaminodipropane dihydrochloride 7.5 m
g, ascorbic acid 5 mg, 35% hydrogen peroxide aqueous solution 5
After 7 mg each was dissolved in 1 g of water and added in this order, the reaction was started and kept at about 60 ° C. for 3 hours. Hexamethylenediamine 2.4 g was dissolved in water 20 g and added to neutralize acrylic acid. The obtained gel was dried at 108 ° C. with a vacuum dryer, and the obtained dried solid was pulverized to obtain an irregularly shaped polymer powder. Table 1 shows the property evaluation results of the water absorbent resin 2 obtained here.

Reference Example 4 Method for Producing Water Absorbent Resin 3 The same procedure as in Reference Example 2 was followed except that a dispersion of an aqueous solution of a hydrolyzate of polysuccinimide having a methacryl group introduced was not added. A polymer powder was obtained. Table 1 shows the characteristic evaluation results of the water absorbent resin 3 obtained here.

Reference Example 5 Method for Producing Water-Absorbent Resin 4 Except that a dispersion solution of an aqueous solution of a hydrolyzate of a polysuccinimide having a methacryl group introduced therein was not added, the synthesis was carried out in the same manner as in Reference Example 3, and a spherical A polymer powder was obtained. Table 1 shows the property evaluation results of the water absorbent resin 4 obtained here.

[0087]

[Table 1]

<< Example 1 >> and << Example 2 >> Polypropylene having a basis weight of 20 g / m ^2-
Using a nonwoven fabric having a polyethylene core-sheath structure, the water-absorbent resin 1 and the water-absorbent resin 2 obtained in Reference Examples 2 and 3 were sprayed on the above-mentioned sheet at a rate of 20 g / m ² as a water-trapping layer. Next, this was sandwiched by the same nonwoven fabric, cut into a size of 10 cm × 10 cm, and the periphery was heat-sealed to obtain a dew condensation water trap sheet 1 and a dew condensation water trap sheet 2. The dew condensation water trap sheet 1 and the dew condensation water trap sheet 2 of the present invention obtained above are referred to as Examples 1 and 2, respectively, and the water capture, moisture absorption, moisture release rate, and repeated moisture release during dew condensation are evaluated. The results are shown in Table 2.

<< Comparative Example 1 >> and << Comparative Example 2 >> Using the water-absorbent resin 3 and the water-absorbent resin 4 obtained in Reference Examples 4 and 5, in the same manner as in the example, the dew condensation sheet Create, water capture at the time of dew condensation, moisture absorption, moisture release rate,
The repeated moisture release was evaluated. Table 2 shows the results.

[0090]

[Table 2]

The evaluation criteria shown in Table 2 are as follows. Evaluation standard of water catching: ○: smooth, dry feeling ×: sticky, no dry feeling XX: wet, dry

Evaluation criteria for moisture release: は: smooth, dry feeling ×: sticky, dry feeling XX: wet, dry feeling

Evaluation criteria for repeated moisture release: ○: smooth, dry feeling ×: sticky, no dry feeling XX: wet, dry feeling

[0094]

According to the present invention, in a water-permeable sheet-like base material and a condensation water-absorbing sheet having a water-absorbing material on or in the base material, the water-absorbing material comprises a water-absorbing resin. By using a water-absorbing resin that contains a polyacidic amino acid or a salt thereof, a part or all of the water-absorbing resin can improve the moisture release property and increase the reusability. By using the dew condensation sheet of the present invention, dew condensation water generated on container ceilings and container inner wall surfaces, walls of houses and other buildings, hollow layers in walls, steel columns and beams of steel-framed houses, water pipes, etc. By catching water, it is possible to prevent corrosion damage caused by dripping of dew water.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiki Hasegawa 2-26-503, Yuzen-cho, Nishinomiya-shi, Hyogo (72) Inventor Toshige Tanaka 3-3-3-202 Futadamachi, Izumiotsu-shi, Osaka F-term (Ref.)

Claims (4)

[Claims] Claims: 1. A water-permeable sheet-like substrate, and a dew condensation water-absorbing sheet having a water-absorbing material on or in the substrate,
A water-condensing sheet, wherein the water-absorbing material contains a water-absorbing resin, and a part or all of the water-absorbing resin is a water-absorbing resin containing a polyacid amino acid or a salt thereof. 2. A water-absorbent resin comprising a polyacid amino acid or a salt thereof, comprising: an anhydrous polyacid amino acid (A) having at least one ethylenically unsaturated bond in a molecule;
The water condensation sheet according to claim 1, which is a water-absorbent resin obtained by reacting the ethylenically unsaturated compound (B). 3. A water-absorbent resin containing a polyacidic amino acid or a salt thereof, comprising: an anhydrous polyacidic amino acid (A) having at least one ethylenically unsaturated bond in a molecule;
The water condensation sheet according to claim 1, which is a water-absorbing resin obtained by reacting the ethylenically unsaturated compound (B) and the polysaccharide (C). 4. The dew trap according to claim 1, wherein the water trapping material on or in the substrate is a water trapping material having both a hygroscopic property and a moisture releasing property. Water sheet.