JPH11319468A - Dehumidifying or drying agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the judgement that a dehumidifying or drying agent has to be renewed by causing a change in color and/or color tone when moisture is absorbed to easily judge whether the agent absorbs moisture or not. SOLUTION: This dehumidifying or drying agent consists of 10-95 mass % powdery or granular deliquescent org. salt A, 90-5 mass % gelling agent B and a 0.000001-10 mass % colorant C with the color and/or color tone changed when moisture is absorbed, based on the total mass of A plus B, and the color and/or color tone are changed when moisture is absorbed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a dehumidifying or drying agent. More specifically, the present invention relates to a dehumidifying or drying agent using deliquescent inorganic salts.

[0002]

2. Description of the Related Art Conventionally, various dehumidifying or drying agents have been widely used for home use and business use. As such dehumidifying or drying agents, deliquescent inorganics represented by calcium chloride, magnesium sulfate and the like are used. Salts are known. These deliquescent inorganic salts are usually used in plastic containers or moisture-permeable film containers.However, if a large amount of water is absorbed, the deliquescent inorganic salts become a transparent liquid, and the plastic containers may be overturned. When pressure is applied to a semipermeable membrane or the like, there is a problem that a high-concentration aqueous solution of a deliquescent inorganic salt that has absorbed moisture spills or oozes out of a container to contaminate the surroundings. As a method for solving such a problem by thickening or gelling the deliquescent high-concentration aqueous salt solution, a dehumidifier in which a water-soluble polymer such as polyvinyl alcohol, sodium polyacrylate, or sodium alginate is mixed with a deliquescent inorganic salt is disclosed. Kosho 60-2
No. 8531) A dehumidifying or drying agent containing a polyacrylamide polymer and a deliquescent inorganic salt (JP-A-63-2)
No. 52524), a hygroscopic composition comprising a mixture of a cationic water-absorbing resin and a deliquescent inorganic salt (JP-A-4-784).
No. 15) has been proposed.

[0003]

However, the gelling agents used in the above methods (1) to (4) are not always practically satisfactory.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above situation. As a result, a dehumidifying or drying agent comprising a deliquescent inorganic salt, a gelling agent and a coloring agent is converted into a high-concentration aqueous solution of the deliquescent salt. However, the present invention was found to quickly absorb to form a gel, and to change the color at the time of moisture absorption, so that it was very easy to confirm the effect of moisture absorption and to determine the dehumidification or replacement of the desiccant.

That is, the present invention provides a deliquescent inorganic salt (A)
10 to 95% by weight of powder and / or granules of the above, 90 to 5% by weight of the gelling agent (B), and 0.000001 to 10% by weight of the total weight of (A) and (B). A dehumidifying or drying agent comprising a coloring agent (C) that sometimes changes color and / or color tone and, if necessary, a pH adjusting agent (D), wherein the color and / or color tone changes when moisture is absorbed.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, powders and / or granules of deliquescent inorganic salts include powders and / or granules of calcium chloride, magnesium chloride, magnesium sulfate, calcium sulfate and the like. These may be anhydrous salts or salts having water of crystallization. Further, some of these can be used in combination. Of these, calcium chloride and magnesium sulfate are preferably used in terms of both moisture absorption performance and cost. The particle size of the above-mentioned powder and / or granular material depends on the method of blending and the like, but is preferably 1 to 10000 µ, more preferably 10 to 5000 µ.

The gelling agent (B) used in the present invention may be an anionic or cationic polymer as long as it can gel and thicken a high-concentration aqueous solution of a deliquescent inorganic salt. The water-soluble polymer (S) mainly composed of nonionic constitutional units or the hydrophilic crosslinked polymer (I) mainly composed of nonionic constitutional units is preferable in that a high-concentration aqueous solution of salts is easily gelled. The hydrophilic crosslinked polymer (I) is more preferred in that the amount of water is high. Examples of the water-soluble polymer (S) include polysaccharides represented by soluble starch, dextrin, alkylcellulose, hydroxyalkylcellulose, etc .; polyvinyl alcohol, polyethylene oxide, and a copolymer of vinyl acetate and alkyl (meth) acrylate. , A (co) polymer of a nonionic water-soluble ethylenically unsaturated monomer (d) and optionally an anionic water-soluble ethylenically unsaturated monomer (e), and the like, and the like. Molecular weight 300
0 to 10000000 synthetic polymers; and the like. Here, the alkyl (meth) acrylate is
It means alkyl acrylate and / or alkyl methacrylate, and will be similarly described below. Examples of the hydrophilic crosslinked polymer (I) include, in addition to a crosslinked product of polyvinyl alcohol, a crosslinked product of polyethylene oxide, a crosslinked product of a water-soluble polysaccharide, and the like, a nonionic water-soluble ethylenically unsaturated monomer (d ) And, if necessary, (co) polymerizing and cross-linking an anionic water-soluble ethylenically unsaturated monomer (e).

The nonionic water-soluble ethylenically unsaturated monomer (d) used for preparing the water-soluble polymer (S) and the hydrophilic cross-linked polymer (I) includes, for example, (meth) Acrylamide, N-alkyl-substituted (meth) acrylamide [N-methylacrylamide, N,
N-dimethylacrylamide, etc.], N-vinylacetamide, hydroxyalkyl mono (meth) acrylate having an alkyl group having 2 to 3 carbon atoms, polyethylene glycol (Mw: 100 to 4000) mono (meth) acrylate, polypropylene glycol (Mw : 100-40
00) Mono (meth) acrylate, methoxypolyethylene glycol (Mw: 100-4000) Mono (meth)
Acrylate and the like can be exemplified, and any nonionic water-soluble ethylenically unsaturated monomer may be used. These monomers (d) may be used alone or in combination of two or more if necessary. Among these nonionic water-soluble ethylenically unsaturated monomers (d), preferred is (meth) acrylamide, which is inexpensive and has good polymerizability. Optionally used anionic water-soluble ethylenically unsaturated monomer (e)
Examples thereof include: (meth) acrylic acid (alkali metal salt), maleic acid (alkali metal salt), fumaric acid (alkali metal salt), itaconic acid (alkali metal salt), and acrylamide-2-methylpropanesulfonic acid (alkali) Metal salt), sulfoalkyl (meth) acrylate, styrenesulfonic acid (alkali metal salt) and the like. Here, (meth) acrylic acid (alkali metal salt) refers to (meth) acrylic acid and / or (meth) acrylic acid.
It means an alkali metal salt of acrylic acid, and will be similarly described below. Preferred among the anionic water-soluble ethylenically unsaturated monomers (e) are alkali metal salts of (meth) acrylic acid and its partially neutralized salts, which are inexpensive and have good polymerizability. Can be mentioned.

The mass ratio of (d) to (e) in the water-soluble ethylenically unsaturated monomer for obtaining the water-soluble polymer (S) or the hydrophilic cross-linked polymer (I) is usually (d) / ( e)
= 80-100 / 20-0, preferably (d) /
(E) = 90-100 / 10-0, more preferably (d) / (e) = 95-99 / 1-5. If the proportion of (d) exceeds 20% by mass, the anionicity of the produced polymer becomes too strong, and the absorption of a high-concentration aqueous solution of deliquescent inorganic salts is undesirably reduced. It depends on the type of the deliquescent inorganic salts, the mixing ratio of the deliquescent inorganic salts and the water-soluble polymer (S) or the hydrophilic cross-linked polymer (I) mainly composed of nonionic constituent units, the structure of the dehumidifying or drying agent, and the like. , (E) is 1 to 5% by mass, the swelling property of (S) or (I) with respect to the high concentration aqueous solution of the deliquescent inorganic salt is improved, the gelation speed is increased, and the swelling ratio is also increased. Therefore, it is more preferable.

In the present invention, the degree of neutralization of the anionic water-soluble ethylenically unsaturated monomer (e) unit is preferably from 60 to 100 mol%, more preferably from 70 to 100 mol%. When the degree of neutralization is 60 mol% or more, the anion is sufficiently dissociated, and the absorption amount and the absorption rate increase.
The neutralization of (e) is performed by alkali metal salt (sodium hydroxide,
(Eg, hydroxides of alkali metals such as potassium hydroxide and lithium hydroxide). (E)
May be neutralized at the ethylenically unsaturated monomer stage before polymerization or by adding an alkali metal hydroxide to the hydrogel after polymerization.

In the present invention, in order to obtain a water-soluble polymer (S) or a hydrophilic cross-linked polymer (I) mainly composed of a nonionic constitutional unit, a nonionic water-soluble ethylenically unsaturated monomer (d) is used. When performing (co) polymerization with the anionic water-soluble ethylenically unsaturated monomer (e), if necessary, other monoethylenically unsaturated monomers may be further substituted with (d) and (e). 10% by mass based on the total mass of
May be copolymerized within a range not exceeding. Examples of such a monoethylenically unsaturated monomer include (meth) alkyl acrylate and vinyl acetate.
There is no particular limitation as long as it is an ethylenically unsaturated monomer copolymerizable with (d) and (e). These ethylenically unsaturated monomers may be used in combination of two or more in a predetermined amount range.

In the present invention, the hydrophilic crosslinked polymer (I) mainly composed of a nonionic constitutional unit is prepared by adding a crosslinking agent (f) at an optional stage and crosslinking. The method of adding the cross-linking agent (f) is as follows.
At least one polymerizable cross-linking agent (f1) is added at the time of polymerization, and a nonionic water-soluble ethylenically unsaturated monomer (d) and an anionic water-soluble ethylenically unsaturated monomer ( e) or a reactive cross-linking agent (f2) having two or more functional groups that react with the functional group of the water-soluble ethylenically unsaturated monomer used is added during and / or after the polymerization. To crosslink. Also,
At least one functional group that reacts with the functional group of the water-soluble ethylenically unsaturated monomer and at least one polymerizable double bond
The cross-linking agent (f3) may be added during polymerization for use. The amount of the crosslinking agent (f) to be added depends on the absorption and water retention of the required dehumidifying or drying agent and the type of the crosslinking agent used, but is preferably 0.00001 to 10% by mass, more preferably 0.1% by mass. 001 to 5% by mass. Addition amount is 0.0
If it is less than 0001% by mass, the gel elasticity may be low, while if it exceeds 10% by mass, the crosslink density may be too high and the swelling and water retention may decrease.

When the cross-linking agent (f) is used, the polymerizable cross-linking agent (f1) has two or more double bonds in the molecule and is used as a nonionic water-soluble ethylenically unsaturated monomer. The crosslinking agent is not particularly limited as long as it is a crosslinking agent copolymerizable with the compound (d) and the anionic water-soluble ethylenically unsaturated monomer (e) used as required, and examples thereof include N, N'-methylenebisacrylamide and ethylene glycol. Di (meth) acrylate, trimethylolpropane di (meth) acrylate,
Trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerin diallyl ether, glycerin triallyl ether, trimethylolpropane diallyl ether, trimethylol Examples thereof include propane triallyl ether, pentaerythritol diallyl ether, pentaerythritol triallyl ether, and pentaerythritol tetraallyl ether. These (f1) may be used in combination of two or more kinds.

The reactive crosslinking agent (f2) used in the present invention
Although it depends on the functional group composition of the polymer to be crosslinked, for example, a polyvalent glycidyl compound represented by ethylene glycol diglycidyl ether, a polyvalent isocyanate compound represented by MDI, an ethylene diamine, and the like Examples thereof include polyhydric amine compounds and polyhydric alcohol compounds represented by glycerin. Examples of the crosslinking agent (f3) having at least one functional group that reacts with the functional group of the water-soluble ethylenically unsaturated monomer and at least one polymerizable double bond include, for example, N 2
-Methylol (meth) acrylamide, glycidyl (meth) acrylate, ethylene glycol monoglycidyl monoacrylate and the like. When these reactive cross-linking agents (f2 and f3) are used, at any stage after the addition of the cross-linking agent, it is usually 100 ° C. or higher, preferably 12 ° C. or more.
Generally, the crosslinking reaction is advanced by heating to 0 ° C. or higher. Further, these reactive crosslinking agents may be used in combination of two or more kinds in a predetermined amount range, and furthermore, a polymerizable crosslinking agent (f1).

Among these crosslinking agents (f), glycerin diallyl ether, glycerin triallyl ether, trimethylolpropane diallyl ether, trimethylolpropane triallyl ether, pentaerythritol diallyl ether, pentaerythritol triallyl ether, pentaerythritol tetraallyl Ether crosslinkers without ester or amide bonds, such as ethers, are less likely to undergo hydrolysis than other crosslinkers even when the pH is slightly higher. Absorbs an aqueous solution with a somewhat high pH, such as a high-concentration aqueous solution of calcium chloride, which is a typical example, and exhibits a stable gel state for a long time even at a relatively high temperature such as in summer, so that it can be preferably used. . Among them, pentaerythritol triallyl ether is more preferable because it has a hydroxyl group in the molecule, has high hydrophilicity, and has three functional groups, has good copolymerizability, and further stabilizes the crosslinked structure.

In the present invention, the method of (co) polymerizing the water-soluble ethylenically unsaturated monomer (d) and, if necessary, (e) may be a conventional method, for example, polymerization using a radical polymerization initiator. Method, a method of irradiating radiation, ultraviolet rays, electron beams and the like. In the method using a radical polymerization initiator, the initiator may be an azo compound [4,4 '
-Azobis (4-cyanovaleric acid), 2,
2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide, 2,2′-azobis (2-amidinopropane) hydrochloride and the like], inorganic peroxides [hydrogen peroxide, potassium persulfate, Ammonium persulfate, sodium persulfate, etc.], organic peroxide [di-t-
Butyl peroxide, cumene hydroperoxide, etc.], a redox initiator [a reducing agent such as a sulfite or bisulfite of an alkali metal salt, ammonium sulfite, ammonium bisulfite, L-ascorbic acid, and a persulfate of an alkali metal salt] Combinations of peroxides such as ammonium persulfate and aqueous hydrogen peroxide], and combinations of two or more of these.

The method of polymerization using this initiator is not particularly limited. For example, the polymerization temperature varies depending on the type of the initiator used, but is preferably from -10 ° C to 100 ° C, and more preferably to increase the molecular weight. −10 ° C. to 80 ° C. The amount of the initiator is not particularly limited, but is preferably 0.000000 to 3.0%, more preferably 0.00%, based on the total mass of the ethylenically unsaturated monomer.
0001 to 0.5%. The solvent at the time of polymerization is usually carried out by aqueous solution polymerization using water having a small chain transfer, but an aqueous solution of an ethylenically unsaturated monomer is optionally used in the presence of a dispersing agent in a hydrophobic solvent (for example, hexane, toluene, So-called reversed-phase suspension polymerization in which the polymer is dispersed and suspended in xylene or the like can also be suitably used. The polymerization concentration, which is the concentration of the ethylenically unsaturated monomer during the polymerization, is preferably from 10 to 60% by mass, and more preferably from 20 to 50% by mass. When the polymerization concentration is 10 to 60%, the molecular weight is easily increased and the efficiency is high, and the polymerization temperature and the like are easily controlled.

In the present invention, when an aqueous gel of a polymer is obtained by aqueous solution polymerization or reverse phase suspension polymerization, it is dried if necessary. The drying method may be a usual method. For example, in the case of aqueous solution polymerization, after the polymer gel is subdivided, air-permeable drying (such as band drying), through-air drying (such as circulation drying), and contact drying (such as drum dryer drying) are performed. In the case of reversed-phase suspension polymerization, a method of performing solid-liquid separation, followed by drying under reduced pressure or through-flow drying can be exemplified.

The dried product of the crosslinked polymer thus obtained is pulverized and pulverized if necessary. The pulverizing method may be an ordinary method, for example, an impact pulverizer (a pin mill, a cutter mill, a skirel mill, an ACM pulperizer, a centrifugal pulverizer, etc.) or an air pulverizer (a jet pulverizer, etc.).

The particle size of the gelling agent (B) used in the present invention varies depending on the purpose and method used, but is preferably from 10 to 2000 μm, more preferably from 50 to 1000 μm in average particle size. When the average particle size is 2000 μm or less, the swelling speed of the gelling agent (B) is increased, and the time required for gelling the dehumidifying or drying agent is increased. When the average particle size is 10 μm or more, the water-soluble polymer is used. Since (S) and the hydrophilic cross-linked polymer (I) are less likely to form mamako, the time until gelation is similarly shortened.

In the present invention, a dehumidifying or drying agent is prepared by mixing powder and / or granules of the deliquescent inorganic salt (A) with the gelling agent (B). In the present invention, the blending mass% ratio of the deliquescent inorganic salt (A) and the gelling agent (B) is as follows:
Usually 10-95 / 90-5, preferably 50-80 / 5
0 to 20. The compounding ratio of the deliquescent inorganic salt (A) is 9
If it exceeds 5% by mass, it becomes difficult to prevent the deliquescent inorganic salts from absorbing moisture and becoming liquefied, and if the ratio of the gelling agent (B) exceeds 90% by mass, the dehumidifying / drying effect becomes weak.

[0022] The dehumidifying or drying agent of the present invention, besides the deliquescent inorganic salt (A) and the gelling agent (B), has a color and / or
Alternatively, in order to change the color tone, a colorant (C) that changes the color and / or the color tone when absorbing moisture is added. Examples of the coloring agent (C) include known dyes (such as direct dyes, acid dyes, basic dyes, disperse dyes, reactive dyes, and IZOC dyes), pigments (such as food coloring pigments), and acid-base indicators (phenolphthalein, thymol). Blue, bromthymol blue, methyl orange, methyl red, etc.). The amount of the colorant (C) used in the present invention varies depending on the type of the colorant used, the desired color strength, and the like. However, usually, the deliquescent inorganic salt (A) and the gelling agent (B) are used. ) To the total mass of 0.000001 to 1
0 mass%, preferably 0.00001 to 1 mass%, more preferably 0.00001 to 0.1 mass%. If the amount of the colorant (C) is less than 0.000001% by mass, the amount of the colorant is too small to change the color well, which is not preferable. On the other hand, if the amount exceeds 10% by mass, the colorant is not preferable. If the amount is too large, the dehumidifier or desiccant dyes the color of the dye or pigment before absorbing moisture, or stains the color of the acid-base indicator itself. It is not preferable because it may be difficult to understand.

The colorant (C) can be added by, for example, adding a powder of the colorant (C), dissolving and diluting (C) in a solvent in which the colorant (C) can be dissolved, and then adding it. However, when a dye, a dye, or a dye and a dye are used as the colorant, the dye or the dye usually has a strong color tone or a strong color tone in a state of being dissolved or dispersed in water or the like. It is better to add dye or pigment powder
This is preferable because the color and color tone of the dehumidifying or drying agent can be easily changed during moisture absorption. When a powder of a dye or a pigment is used as the coloring agent, the particle size varies depending on the type of the dye or the pigment to be used, the purpose of the coloring, the tint, etc., but the uniformity of the coloring is improved (prevention of spot color). Average particle size of 0.0
Preferably, the average particle diameter is from 0.01 to 200 μm.
Those having a thickness of 1 to 100 μm are more preferred. When a dye or pigment powder is used as a coloring agent, the dye or pigment powder is typified by silica, silicon oxide, zeolite, titanium oxide, calcium carbonate, talc, or the like for the purpose of improving the uniformity of coloring. It may be added after dispersing and diluting into a colorless or white fine powder.

On the other hand, when an acid-base indicator is used as the coloring agent (C), an acid-base indicator powder may be added, but the acid-base indicator may be added to a suitable solvent (for example, ethanol, methanol or the like). After dissolving and diluting in a hydrophilic organic solvent, water, etc.), the addition is preferred because the acid-base indicator can be added uniformly and the uniformity of coloring is improved. Also,
Since acid-base indicators change color due to changes in pH,
When an acid-base indicator is used as a coloring agent, a pH adjuster (D) may be added in combination, if necessary, according to the discoloration range of the acid-base indicator. The pH adjuster (D) depends on the kind of acid-base indicator (discoloration range) to be used, the pH of the deliquescent inorganic salt (A) itself when it contains water, the pH of the gelling agent (B) itself when it contains water, and the like. Variously different, depending on the case, the co-addition of the pH adjuster (D) is not always necessary,
At the pH of the water content of the dehumidifier or desiccant, the pH should be adjusted so that the discoloration and color tone change of the acid-base indicator can be successfully achieved using the discoloration area.
The adjuster (D) may be appropriately selected and, if necessary, added in combination with an acid-base indicator. The amount of the pH adjuster (D) to be added is not particularly limited as long as it can be adjusted to a desired pH. However, in order to prevent the hygroscopicity of the deliquescent inorganic salts and the gelling power of the gelling agent from decreasing, the deliquescent property is reduced. Inorganic salts (A) and gelling agents (B)
Is preferably from 0.001 to 10% by mass based on the total mass of

The coloring agent (C) may be added at any stage. For example, a gelling agent (B) may be added to the deliquescent inorganic salt (A) and then mixed with the gelling agent (B). B) Add a colorant (C) in an optional manufacturing process, and then mix with the deliquescent inorganic salt (A). Simultaneously mix the deliquescent inorganic salt (A) and the gelling agent (B) at the same time. A method such as adding and mixing (C) can be exemplified.

When the deliquescent inorganic salt (A) and the gelling agent (B) are blended in the dehumidifying or drying agent of the present invention,
If necessary, other additives may be added. Examples of the other additives include silica gel, zeolite, perlite, bentonite, vermiculite, activated carbon, and the like, but are not particularly limited as long as they do not interfere with the function of the dehumidifying or drying agent. Not something. The amount used is not particularly limited as long as it does not interfere with the function, but is preferably 10% by mass or less based on the total mass of the deliquescent inorganic salt (A) and the gelling agent (B). Two or more of these additives may be added in combination.

There is no particular limitation on the form of use of the dehumidifying or drying agent of the present invention. For example, a dehumidifying or drying agent which passes gas such as moisture but does not pass powder or liquid, such as a permeable film container. Examples of the method include a method of encapsulating an agent composition as a dehumidifying or drying agent, a method of putting a dehumidifying or drying agent composition in a plastic container, and sealing the opening with a moisture-permeable film or nonwoven fabric. As the moisture-permeable film, a known film may be used. For example, a fine inorganic filler of about 0.1 to 20 μm is blended into a thermoplastic resin represented by polyethylene, polypropylene, polyvinyl chloride, polyester, polyamide, or the like. Stretched porous sheets and the like can be suitably used. In addition, a film obtained by laminating a nonwoven fabric and a moisture-permeable film for improving the strength of the moisture-permeable film is also suitable. In addition, the above-mentioned moisture-permeable film usually has poor transparency, and it is difficult to confirm the state inside the dehumidifying or drying agent.To observe the state of moisture absorption inside the dehumidifying or drying agent, a moisture absorbing layer using a moisture-permeable film on one side is used. Alternatively, a normal film having high transparency may be used for the other surface.

There is no particular limitation on the method of forming the container. For example, a method of forming a sheet made of the above-mentioned moisture-permeable film into a bag-like form, or bonding and fusing the opening of a moisture-impermeable container with the above-mentioned sheet or nonwoven fabric For example, a method of sealing by such means can be exemplified. When these moisture-permeable materials are used, the exterior of the moisture-permeable film container or the like is further covered with a moisture-impermeable material, and when used as a dehumidifying or drying agent, the moisture-impermeable exterior material is broken. It is more suitable for actual use to start the use of the dehumidifying or drying agent at an appropriate timing by a method such as removal or the like.

[0029]

The present invention will be further described with reference to the following examples and comparative examples, but the present invention is not limited to these examples. Gelation rate, swelling and water retention of 40% calcium chloride aqueous solution of gelling agent used in the present invention and comparative dehumidifying or drying agent, and coloring test and gelation state of the present and comparative dehumidifying or drying agent The leaching test under pressure was tested by the following method. Hereinafter, unless otherwise specified,% indicates mass%.

Gelation rate of 40% calcium chloride aqueous solution of gelling agent: 2000 g of anhydrous calcium chloride (reagent, special grade) and 3000 g of ion-exchanged water in a 5 liter beaker
And stirred to prepare a 40% calcium chloride aqueous solution. Put 10 g of gelling agent in a 200 ml beaker, and pour 100 g of 40% calcium chloride aqueous solution on top,
The time until the entire solution gelled was defined as the gelation rate.

Amount of swelling / water retention of 40% calcium chloride aqueous solution of gelling agent: 2.0 g of gelling agent was placed in a 250-mesh nylon screen and immersed in a 40% calcium chloride aqueous solution for 5 hours. The nylon screen was pulled up and drained for 30 minutes, and the amount of swelling was measured by the following equation. Swelling amount (g / g) = (mass of nylon screen after immersion−mass of nylon screen) / 2 Place the drained nylon screen in a centrifuge,
After centrifugation at an acceleration of 00G for 3 minutes, the water retention was measured by the following equation. Water retention (g / g) = (mass of nylon screen after centrifugation-mass of nylon screen) / 2

Discoloration test of dehumidifying or drying agent: 16 cm × 1
1 cm moisture permeable film [Poram, Tokso Co., Ltd.
Polyethylene film having a pore size of 5 μm and a thickness of 50 μm) and a non-woven fabric (PP / PE gescore) and a moisture-impermeable film (thickness 30).
μm transparent PP / PE laminated film), and heat-seal three sides (each 1 cm) to form a bag having a moisture-permeable film layer on one side. 50 g of the dehumidifying or desiccant composition described in Examples or Comparative Examples was placed in this bag, and the upper part of the bag was heat-sealed to prepare a dehumidifying or desiccant.
The dehumidifying or drying agent is placed in a thermo-hygrostat at 30 ° C. and 90% humidity for 3 days to absorb the dehumidifying or desiccant, and the color of the dehumidifying or desiccant composition before and after moisture absorption and the color at the time of moisture absorption Was observed and evaluated according to the following criteria. ：: The color of the dehumidifying or drying agent composition was completely changed due to moisture absorption, and the color change occurred uniformly. Δ: The color of the dehumidifying or drying agent composition has completely changed due to moisture absorption, but there are slight shades of color and pills. ×: The color of the dehumidifying or drying agent composition did not change even after absorbing moisture, or the change in color was difficult to recognize.

Gelation state of dehumidifying or drying agent: 16 cm ×
11 cm moisture permeable film [Poram, Tokso Co., Ltd.
Polyethylene film having a pore size of 5 μm and a thickness of 50 μm) and a non-woven fabric (PP / PE gescore) and a moisture-impermeable film (thickness 30).
μm transparent PP / PE laminated film), and heat-seal three sides (each 1 cm) to form a bag having a moisture-permeable film layer on one side. 50 g of a dehumidifying or desiccant composition [anhydrous calcium chloride (special reagent grade) / gelling agent: 4/1] was placed in the bag, and the upper portion of the bag was heat-sealed to prepare a dehumidifying or desiccant. The dehumidifying or drying agent was placed in a thermo-hygrostat at 30 ° C. and 90% humidity for 3 days to absorb the dehumidifying or drying agent, and the gelation state of the dehumidifying or drying agent composition was observed.

Exudation test of dehumidifying or drying agent: After performing the moisture absorbing test, the dehumidifying or drying agent was placed with the moisture-permeable film side up, and 10 filter papers cut into 16 cm × 11 cm were stacked thereon. Furthermore, a plastic plate (1
6 × 11 cm, thickness: 5 mm) and 5k from above
g of weight and pressurized the dehumidifying or drying agent for 3 minutes. After pressurization, the mass of the filter paper was measured, and the amount of seeping out of the dehumidifying or drying agent composition was measured by the following equation. Seepage amount (g) = mass of filter paper after test (g)-mass of filter paper before test (g)

Example 1 In a 5 liter beaker, 14.4 g of acrylic acid was added.
(0.2 mol) in 48% aqueous sodium hydroxide solution 1
6.5g, 50% acrylamide aqueous solution 1391.6g
(9.8 mol), 0.5 g of pentaerythritol triallyl ether [manufactured by Daiso Corporation], and 1390 g of water were added, and the mixture was cooled to 5 ° C. This solution was put into an adiabatic polymerization tank, and the dissolved oxygen content of the solution was adjusted to 0.1 ppm through nitrogen. Then, 0.0005 g of 35% hydrogen peroxide solution, 0.00025 g of L-ascorbic acid, and 4,4′-azobis 0.125 g of (4-cyanovaleric acid) was added. After about 30 minutes, the polymerization started, and after about 5 hours, the maximum temperature reached about 75 ° C., and the polymerization was completed, and a hydrogel polymer was obtained. After this gel was subdivided with a meat chopper, it was dried at 120 ° C. for 1 hour using a band dryer (air-permeable dryer, manufactured by Inoue Metal Co., Ltd.) and pulverized to form a white gel having an average particle diameter of 500 μm. Agent (1) was obtained. The gelling speed, swelling amount and water retention amount of the gelling agent (1) were measured. Table 1 shows the results. To 100 g of the obtained gelling agent (1), 0.001 g of powder (average particle size: 150 μm) of a commercially available food coloring dye No. 1 (reagent) was added, and the powder was uniformly blended. The product (reagent grade) (400 g) was added to prepare a dehumidifying or drying agent composition of the present invention. A dehumidifying or drying agent was prepared by the method described in the above test method, and a discoloration test, observation of a gel state, and a seepage test were performed. Table 2 shows the results.

Example 2 In the same manner as in Example 1 except that a finely pulverized food additive blue No. 1 having an average particle size of 30 μm was used instead of the commercially available food additive blue No. 1 used in Example 1, Thus, a dehumidifying or drying agent composition of the present invention was prepared. A dehumidifying or drying agent was prepared by the method described in the above test method, and a discoloration test, observation of a gel state, and a seepage test were performed. Table 2 shows the results.

Example 3 To 100 g of the gelling agent (1) obtained in Example 1, 1 g of a 1% ethanol solution of bromthymol blue (special reagent grade) as an acid-base indicator was added by spraying (addition amount: 0.01 g).
And mixed evenly. To this was added 400 g of anhydrous calcium chloride granules (special grade reagent) to prepare the dehumidifying or drying agent composition of the present invention. A dehumidifying or drying agent was prepared by the method described in the above test method, and a discoloration test, observation of a gel state, and a seepage test were performed. Table 2 shows the results.

Example 4 Commercially available disperse dye [DIANIX NABY BLUE
SR-SE, manufactured by Mitsubishi Chemical Corporation] was pulverized to an average particle size of 40 μm. Granules of anhydrous calcium chloride (special grade reagent) 4
00g, polyvinyl alcohol [PVA] as a gelling agent
-224E, manufactured by Kuraray Co., Ltd., the physical properties of which are listed in Table 1 as a gelling agent (2)] 100 g, and 0.01 g of the pulverized disperse dye are placed in a plastic bag and uniformly powder-blended.
A dehumidifying or desiccant composition of the present invention was made. A dehumidifying or drying agent was prepared by the method described in the above test method, and a discoloration test, observation of a gelation state, and a seepage test were performed. Table 2 shows the results.

Example 5 Commercially available soluble starch [reagent, manufactured by Wako Pure Chemical Industries, Ltd.
The physical properties of the gelling agent (3) are shown in Table 1.] 5 g of a 1% ethanol solution of phenolphthalein, an acid-base indicator (addition amount: 0.05 g), is added to 100 g by spraying.
The ethanol was distilled off by heating. 0.1 g of tris (hydroxymethyl) aminomethane (pH adjuster, pH = 12) is added to 400 g of anhydrous calcium chloride granules (special grade reagent).
10 g of a 10% methanol solution was added by spraying. 100 g of starch treated with an acid-base indicator and 400 g of anhydrous calcium chloride granules treated with a pH adjuster were mixed to prepare a dehumidifying or drying agent composition of the present invention. A dehumidifying or drying agent was prepared by the method described in the above test method, and a discoloration test, observation of a gelation state, and a seepage test were performed. Table 2 shows the results.

Comparative Example 1 A comparative dehumidifying or drying agent composition was prepared in the same manner as in Example 4 except that no disperse dye was added. A dehumidifying or drying agent was prepared by the method described in the above test method, and a discoloration test, observation of a gelation state, and a seepage test were performed. Table 2 shows the results.

Comparative Example 2 A comparative dehumidifying or drying agent composition was prepared in the same manner as in Example 5, except that the acid-base indicator and the pH adjuster were not added. A dehumidifying or drying agent was prepared by the method described in the above test method, and a discoloration test, observation of a gelation state, and a seepage test were performed. Table 2 shows the results.

Comparative Example 3 400 g of anhydrous calcium chloride granules and commercially available sodium polyacrylate [ALONBIS S, manufactured by Nippon Pure Chemical Co., Ltd .; It does not correspond to the gelling agent (B) used in the present invention since a high-concentration aqueous solution of salts does not gel or thicken), and a comparative dehumidifying or drying agent composition was prepared. A dehumidifying or drying agent was prepared by the method described in the above test method, and a discoloration test, observation of a gelation state, and a seepage test were performed. Table 2 shows the results.

[0043]

[Table 1]

[0044]

[Table 2]

From Tables 1 and 2, the following is clear. Unlike the dehumidifying or drying agents of Comparative Examples 1 to 3, the dehumidifying or drying agents of Examples 1 to 5 completely change the color of the dehumidifying or drying agent before and after moisture absorption. In addition, the dehumidifying or drying agents of Examples 2 to 5 have very uniform coloring when absorbing moisture. In particular, the gelling agent (1) used in Examples 1 to 3 is superior in gelation rate, swelling amount and water retention amount as compared with other gelling agents, and the dehumidifying or drying agent composition when absorbing moisture is used. Since it becomes a gel-like solid, even if pressure is applied to the dehumidifying or desiccant, the dehumidifying or desiccant composition absorbed from the moisture-permeable film or the like does not permeate.

[0046]

The dehumidifying or drying agent of the present invention has the following effects. Since the dehumidifying or drying agent of the present invention undergoes a change in color and / or color tone when absorbing moisture, it is easy to determine from the outside whether or not the dehumidifying or drying agent has absorbed moisture. It's easy to do. In particular, when a hydrophilic cross-linked polymer mainly composed of nonionic structural units is used as a gelling agent, a high-concentration aqueous solution of a polyvalent metal salt that has absorbed moisture from deliquescent inorganic salts such as calcium chloride and magnesium sulfate can be rapidly prepared. In addition, it absorbs and retains a large amount of water and becomes a gel-like solid. Therefore, even if the moisture-absorbing dehumidifying or desiccant container is overturned or pressure is applied to the dehumidifying or desiccant pack using a moisture-permeable film or the like, the deliquescent salt solution does not spill or seep out at all. And does not pollute the outside. Because of the above effects, the dehumidifying or drying agent of the present invention is useful as a dehumidifying or drying agent for general home use such as closet, closet, kitchen and the like, and for business use such as in a cafeteria and a warehouse.

Claims (6)

[Claims] 1. A deliquescent inorganic salt (A) powder and / or granular material of 10 to 95% by mass, and a gelling agent (B) 90 to
5% by mass and 0.0 with respect to the total mass of (A) and (B).
00001 to 10% by mass of a coloring agent (C) whose color and / or color tone changes when moisture is absorbed, and a pH adjuster (D) if necessary, wherein the color and / or color tone changes when moisture is absorbed. Dehumidifying or drying agent. 2. The colorant (C) has a content of 0.001 to 200 μm.
2. The dehumidifying or drying agent according to claim 1, wherein the agent is a dye, a pigment, or a powder of a dye and a pigment, which has an average particle diameter of m and changes color and / or color tone when absorbing moisture. 3. The dehumidifying or drying method according to claim 1, wherein the coloring agent (C) is an acid-base indicator whose color and / or color tone changes depending on the pH of the hydrated substance of the dehumidifying or drying agent when absorbing moisture. Agent. 4. The gelling agent (B) is a water-soluble polymer (S) mainly composed of nonionic constitutional units and / or a hydrophilic crosslinked polymer (I) mainly composed of nonionic constitutional units.
The dehumidifying or drying agent according to any one of claims 1 to 3. 5. The gelling agent (B) is a hydrophilic crosslinked polymer (I) mainly composed of a nonionic constitutional unit, wherein (I)
Is a nonionic water-soluble ethylenically unsaturated monomer (d) 9
0 to 100% by mass, 0 to 10% by mass of anionic water-soluble ethylenically unsaturated monomer (e), and 0.00001 to 10% by mass based on the total mass of (d) and (e) The dehumidifying or drying agent according to claim 4, which is a crosslinked polymer comprising (f). 6. The method according to claim 5, wherein the monomer (d) is (meth) acrylamide and the monomer (e) is an alkali metal neutralized salt or a partially neutralized salt of (meth) acrylic acid. Dehumidifying or drying agent.