JPH0716608B2 - Improved water vapor absorbing and releasing agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improved water vapor absorbing and releasing agents. More specifically, it relates to an improved water vapor absorbing and releasing agent obtained by integrating a water-insoluble polymer of a specified (meth) acrylamide derivative with a hygroscopic inorganic compound.

Conventional technology and its problems: Conventionally, the method of controlling the temperature in the gas is mainly performed by separately operating a device having two functions of dehumidifying and humidifying, which is extremely difficult as compared with the temperature control. Troublesome equipment and work are required.

Therefore, problems such as dew condensation caused by changes in room temperature are not fundamentally solved in enclosed spaces such as greenhouses, greenhouses, and buildings where the inflow of outside air is small, and diseases caused by dew condensation in greenhouses are not solved. Is occurring, or in an office in a building, there are various problems such as failure of electronic devices such as computers.

On the other hand, in the cultivation of crops in dry land or soil with poor water retention, humidification in the soil becomes a problem, and various humidifying agents such as soil water retention agents have been studied.

Recently, with respect to the above-mentioned problems, there is an idea to utilize a hydrophilic resin having a water absorbing ability for humidity control, in addition to the conventional idea of air conditioning, and various trials have been made.

The present inventors have conducted studies for the above-mentioned purpose, and a polymer obtained by insolubilizing a polymer of the specified (meth) acrylamide derivative, which is also applied to the present invention, is a water vapor absorbing and releasing agent. It has been found to be suitable as, and has already proposed its use. Specifically, the agent has a very convenient property as an agent for absorbing and releasing water vapor, which absorbs water vapor well in a low temperature / high humidity state and releases water vapor in a high temperature / low humidity state. However, one drawback is that it has a small amount of moisture absorption, so it can be used without problems in a relatively narrow space or in applications where low humidity conditions are not strongly required, but in a wide space or low humidity is essential. It will not be able to fully exhibit its function in the intended use.

Means for Solving the Problems: As a result of intensive investigations by the present inventors in view of the above problems, a polymer obtained by insolubilizing a specified polymer of a (meth) acrylamide derivative in water and a hygroscopic inorganic compound As a result of the integration of the above, it was found that the moisture absorption amount greatly increases and, surprisingly, the moisture releasing ability is less reduced and a large amount of water vapor can be absorbed and released, and the present invention has been completed.

That is, the present invention is represented by the general formula (I) or (II) (In the above formula, R ₁ is a hydrogen atom or a methyl group, R ₂ is a hydrogen atom,
A methyl group or an ethyl group, and R ₃ is a methyl group, an ethyl group or a propyl group. ) (In the above formula, R ₁ is a hydrogen atom or a methyl group, A is CH _{2 n} and n is 4 to 6 or CH _{2 2} OCH _{2 2.} ) N-alkyl or N-alkylene-substituted (meth) acrylamide alone or It is an improved water vapor absorbing and releasing agent obtained by integrating a hygroscopic inorganic compound with a polymer obtained by insolubilizing a copolymer or a copolymer with another copolymerizable monomer in water.

Examples of the monomer used in the present invention include Nn-
Propyl acrylamide, N-n-propyl methacrylamide, N-isopropyl acrylamide, N-isopropyl methacrylamide, N-ethyl acrylamide,
N, N-diethylacrylamide, N-ethylmethacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N-acryloylpyrrolidine, N-
Methacryloyl pyrrolidine, N-acryloyl piperidine, N-methacryloyl piperidine, N-acryloyl morpholine etc. can be mentioned.

Further, as the monomer copolymerizable with the above-mentioned monomer,
Hydrophilic monomers, ionic monomers, lipophilic monomers, etc. can be mentioned, and one or more of them can be applied. Among them, hydrophilic monomers and ionic monomers are used. Is preferred.

Specifically, examples of the hydrophilic monomer include acrylamide, methacrylamide, N-methylacrylamide,
Examples include diacetone acrylamide, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, various methoxy polyethylene glycol methacrylates, various methoxy polyethylene glycol acrylates, and N-vinyl-2-pyrrolidone. , Vinyl acetate, glycidyl methacrylate, etc. may be introduced by copolymerization and hydrolyzed to impart hydrophilicity. Examples of the ionic monomer include acrylic acid, methacrylic acid, vinyl sulfonic acid,
Acids such as allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, 2-acrylamido-2-phenylpropanesulfonic acid, 2-acrylamido-2-methyl-propanesulfonic acid and salts thereof, N, N-dimethylaminoethyl Amine such as methacrylate, N, N-diethylaminoethyl methacrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl methacrylamide, N, N-dimethylaminopropyl acrylamide, and salts thereof can be mentioned. . Also,
Various acrylates, methacrylates, acrylamides,
It is also possible to introduce methacrylamide, acrylonitrile or the like by copolymerization and hydrolyze it to impart ionicity.

Examples of the lipophilic monomer include Nn-butylacrylamide, N-tert.-butylacrylamide, Nn
-N-alkyl (meth) acrylamide derivatives such as hexyl acrylamide and N-n-octyl methacrylamide, (meth) acrylate derivatives such as ethyl acrylate, methyl methacrylate and butyl acrylate, acrylonitrile, methacrylonitrile, vinyl acetate, styrene, α -Methylstyrene, butadiene, isoprene and the like can be mentioned.

As a method of insolubilizing the above-mentioned monomer polymer in water, there are a method of insolubilizing at the time of polymerization and a method of insolubilizing by treatment after the polymerization, but as a specific insolubilizing method, at least two or more in the molecule. A method of copolymerizing a crosslinkable monomer having a double bond with the above-mentioned (meth) acrylamide derivative, a method of copolymerizing an N-alkoxymethyl (meth) acrylamide derivative, the above lipophilic monomer and a (meth) acrylamide derivative. A method of copolymerizing, a method of polymerizing in bulk, a method of heat-treating the polymer, a method of integrating the polymer with a water-insoluble fibrous substance such as cellulose, and the like can be adopted.

More specifically, in the first method, as the crosslinkable monomer,
For example, N, N'-methylenebisacrylamide, N, N-diallylacrylamide, triacrylformal, N, N
-Diacryloylimide, ethylene glycol acrylate, ethylene glycol dimethacrylate, propylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol dimethacrylate, glycerol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane Triacrylate, divinylbenzene, diallyl phthalate and the like can be used.

The N-alkoxymethyl (meth) acrylamide derivative in the second method also includes N-hydroxymethyl (meth) acrylamide, for example N-methylol (meth).
Acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide,
N-n-butoxymethyl (meth) acrylamide, N-
tert.-Butoxymethyl (meth) acrylamide and the like can be used.

The ratio of the lipophilic monomer to the (meth) acrylamide derivative having an amphiphilic property in the third method varies depending on the combination of the (meth) acrylamide derivative and the lipophilic monomer, and cannot be generally determined. It is 1% or more, preferably 3% or more.

As the method of polymerizing in bulk according to the fourth method, a polymer block is obtained by polymerizing as it is without diluting with a solvent to obtain a polymer block, or by polymerizing in a monomer droplet while suspending in a solvent to obtain a particulate polymer. A method etc. can be adopted.

In the method of heat-treating the polymer which is the fifth method, the heating conditions vary depending on the polymer and are not uniform, but generally, at a temperature of 60 to 250 ° C., preferably 80 to 200 ° C., bulk polymerization, The polymer obtained by suspension polymerization, solution polymerization or the like is heat-treated. At that time, in the solution polymerization, drying or evaporation of the solvent and heat treatment may be combined.

The sixth method is a method of integrating with a fibrous substance or the like, as a fiber such as cellulose, nylon, polyester, acrylic or a non-woven fabric made of polypropylene, ethylene-propylene copolymer or the like, which is insoluble in water. A method of impregnating or graft polymerizing the above-mentioned (meth) acrylamide derivative with a substance or a water-insoluble porous inorganic substance such as silica, alumina, or zeolite, and a method of impregnating a polymer can be adopted.

The above six methods may be adopted individually or in combination. More effective results can be obtained even if they are used together.

As a more specific method of polymerization that can be adopted in producing the water vapor absorbing and releasing agent of the present invention according to the above-mentioned method, for example, (1) a monomer is polymerized as it is without diluting it with a solvent to form a polymer block. How to manufacture,
(2) Polymerization in a solvent to dry after polymerization or precipitation of the polymer in a solvent to obtain a polymer, (3) method to obtain a particulate polymer by suspension polymerization, (4) emulsion polymerization. Method for obtaining coalesced latex (5) A method in which a polymer is integrated with a water-insoluble fibrous substance or a porous inorganic substance by a method such as impregnation of a polymer solution or graft polymerization can be adopted. Further, in the above-mentioned production process, a fibrous substance shredded to 10 mm or less may be added to carry out polymerization or subsequent treatment to produce a polymer in which the fibrous substance is dispersed.

At that time, as a method for initiating the polymerization, heating alone can be used, but normally, a better result is obtained by using a polymerization initiator.

The polymerization initiator is not limited as long as it has the ability to initiate radical polymerization, and examples thereof include inorganic peroxides, organic peroxides, combinations of these peroxides with reducing agents, and azo compounds. Specifically, there are ammonium persulfate, potassium persulfate, hydrogen peroxide, tert-butyl peroxide, benzoyl peroxide, cumene hydroxy peroxide, tert-butyl peroxy-2-ethylhexanoate, butyl perbenzoate and the like. , As reducing agents to be combined with these, mention should be made of sulfite, bisulfite, salts of low ionic value such as iron, copper and cobalt, organic amines such as aniline, and reducing sugars such as aldose and ketose. You can As the azo compound, azobisisobutyronitrile, 2,2'-azobis-2-amidinopropane hydrochloride, 2,2'-azobis-2,4-dimethylvaleronitrile,
4,4'-azobis-4-cyanovaleic acid or the like can be used. It is also possible to use two or more of the above-mentioned polymerization initiators in combination. In this case, the amount of the polymerization initiator to be added is sufficient in the normally employed quantitative range, for example, 0.01 to 5% by weight, preferably 0.05 to 2% by weight, based on the monomer.

Among the polymers obtained in this manner, a block-shaped one, or a polymer obtained by distilling off the solvent, is pulverized into a powder, or melted into a granule, a flake, a fiber or a film. The molded polymer can be provided in the form of the particulate polymer as it is, and the latex polymer can be provided by impregnating and coating with a fibrous substance such as cloth and paper, or by providing a film.

On the other hand, the hygroscopic inorganic compound is not particularly limited as long as it has hygroscopicity, and may be water-soluble or water-insoluble.
Specifically, metal hydrides such as calcium hydride, sulfates such as magnesium sulfate, calcium sulfate, sodium sulfate, and copper sulfate, calcium chloride, calcium bromide, magnesium chloride, zinc chloride, lithium chloride, lithium bromide. Halide salts such as sodium chloride, sodium bromide, potassium chloride, magnesium perchlorate, barium perchlorate, perchlorates such as sodium perchlorate, calcium oxide, magnesium oxide, barium oxide, phosphorus pentoxide, Examples thereof include oxides such as alumina and silica, inorganic acids such as phosphoric acid and sulfuric acid, and molecular sheep. The amount of these inorganic compounds added varies depending on the purpose of use and cannot be specified uniformly, but if the amount added is small, the effect will not be clear,
On the contrary, if the amount is too large, the moisture absorption ability increases, but the moisture release ability, which is a feature of the present invention, is impaired.
˜97 wt%, preferably 5-75 wt%. But,
In any case, it is a great feature of the present invention that even if such a large amount of hygroscopic inorganic compound is added, the decrease in the moisture releasing ability of the agent is small. It is considered that the absorbed water is being given and received. Next, there is a method for producing a water vapor absorbing and desorbing agent by integrating these hygroscopic inorganic compounds into a polymer, and a method of polymerizing and integrating these inorganic compounds at the time of polymer structure, after polymerization, There are a method of integrating an inorganic compound by kneading, a method of integrally molding a polymer and an inorganic compound, and the like. More specifically, the method of integration is also related to the shape of the polymer, and the shape cannot be uniformly defined because its shape depends on how the agent is used.

However, in general, those polymers are often used in the form of powder or granules, or in the form of being impregnated or coated with a fibrous substance such as cloth or nonwoven fabric.

The powdered product undergoes gel polymerization in an aqueous solution as described above,
Then, various methods such as dry pulverization may be used. At that time, it can be integrated by dissolving or dispersing the inorganic compound to be integrated in the polymerization liquid and polymerizing, and further by impregnating or spraying an aqueous solution or dispersion of the inorganic compound to be integrated into a powdery product. Can be integrated.

On the other hand, granular products are generally easily produced by the suspension polymerization method. However, since the acrylamide or methacrylamide derivative used in the present invention is generally highly soluble in water, the suspension polymerization method is Reverse phase suspension polymerization in which a monomer or an aqueous solution thereof is dispersed in oil, salting out suspension polymerization in which a large amount of an electrolyte or the like is dissolved in an aqueous solution to suppress the solubility of a monomer, and further, a polymer A method such as precipitation suspension polymerization in which polymerization is carried out at a high temperature above the cloud point to precipitate the polymer is adopted. In the case of reverse phase suspension polymerization, it can be integrated by dissolving or dispersing an inorganic compound in an aqueous monomer solution, and in either case, granules are impregnated or sprayed with an aqueous solution or dispersion of an inorganic compound. do it. When the fibrous substance is used in the form of being impregnated or coated, the inorganic compound may be dissolved or dispersed in the aqueous solution to be impregnated or coated, or the fibrous substance after impregnated or coated is an aqueous solution of the inorganic compound. Alternatively, the dispersion may be impregnated or sprayed, but the former is more convenient because it requires only one step. In addition to fibrous substances, silica, alumina,
Porous materials such as zeolites can also be used.

The water vapor absorbing and releasing agent produced as described above is in a solid state, and absorbs and holds water by contact with gaseous water, for example, moisture in the atmosphere, and by the humidity and temperature of the outside air,
Water can be absorbed and released and this process can be repeated. Generally, under a constant water vapor partial pressure, the amount of moisture absorbed at low temperatures is larger than the amount of moisture absorbed at high temperatures, so it is possible to act as a dehumidifying agent at low temperatures while acting as a humidifying agent at high temperatures. It has the function of reducing changes in relative humidity and keeping the relative humidity constant.

The water vapor absorption amount and the release agent absorption amount vary depending on the polymer composition and temperature / humidity conditions, but the water vapor can absorb about 0.1 to 10 times as much water vapor as its own weight. At that time, the moisture absorption amount of the integrated products may be larger than the moisture absorption amount of each of them alone, and a synergistic effect is recognized by the integration.

Such a high hygroscopic amount cannot be obtained by being integrated with a hygroscopic organic compound, and is obtained only after being integrated with a hygroscopic inorganic compound.

It is possible to quickly release the moisture by placing the hygroscopic agent in an environment having a higher temperature or an environment having a lower humidity. As described above, the moisture absorption and the moisture release can be promptly performed by changing the surrounding environmental conditions. In particular, one of the features of the present invention is that the moisture release rate can be set to be equal to or higher than the moisture absorption rate, which is a property that conventional moisture absorbents do not have.

In the repeated use of the water vapor absorbing and releasing agent of the present invention, the larger the amount of moisture absorption, the greater the amount of water remaining in the agent after moisture is released. The difference with the water content also becomes large at the same time, so it is not a big problem in repeated use.

Therefore, the agent for absorbing and releasing water vapor according to the present invention can easily control the amount of moisture absorption, and it is possible to control the humidity of a large volume of gas in the presence of a small amount of the agent.

A specific method for controlling the humidity using the water vapor absorbing and releasing agent of the present invention is to contact the agent with the gas to be humidity controlled.

The shape of the agent is not particularly limited, and powdery, granular, flake-like, fibrous, film-like, or a combination thereof with other fibrous materials can be used according to the application. As a concrete method of compounding, a method of sandwiching the agent with a fiber material such as a cloth or a non-woven fabric and integrating them by heat fusion, adhesion or the like can be adopted. At that time, it can be heated or dehumidified by the temperature and humidity of the atmosphere, and can be repeated as many times as the atmosphere changes.

As a more specific method for absorbing and releasing water vapor (1)
Mainly, a method of installing the agent in an atmosphere and absorbing and releasing water vapor depending on the function of the agent, and (2) a method of absorbing and releasing water vapor by controlling the temperature of the agent. Two methods can be adopted. Powder, granular,
In the case of using the flake-like agent, in the method (1), the agent and the gas may be brought into contact with each other in a fixed bed, a fluidized bed, a moving bed or the like. In the method (2), the above-mentioned manner may be adopted so that the agent can be heated or cooled by a method such as external heat exchange or internal heat exchange.
On the other hand, in a fibrous form, a film form or a composite of the agent with a fibrous material, a film or the like, it may be adhered to a wall like a wallpaper, or may be hung in a room like an awning or a curtain, In any case, it is sufficient if it is possible to make sufficient contact with the moisture in the gas. When the method of (2) is adopted in this manner, it is not as easy as the method of (1), but for example, the above-mentioned agent is processed into a tube and steam, water and temperature are adjusted therein. A method of heating and cooling by flowing gas or the like, or a method of heating or cooling from the outside when the above-mentioned agent is used as a curtain, awning, wallpaper or the like on a wall or the like is adopted.

Also, by appropriately selecting the composition and amount of the agent, it is possible to set the humidity in the gas to be higher or lower, and when a low moisture absorption amount is used, it can be set in a high humidity range. It can be set to a low humidity range when using a material with a high moisture absorption.

Specific applications include greenhouses, greenhouses, humidity control during cultivation of crops in enclosed spaces such as greenhouse horticulture using vinyl film, humidity control in rooms with computers and other electronic devices that are sensitive to high humidity, and general housing. The prevention of dew condensation on the walls, windows, etc., and the humidity control in the soil can be mentioned.

Action: As described above, the water vapor absorbing and releasing agent of the present invention can control the low humidity in a wide range by changing the addition amount of the inorganic compound to be integrated first. It can absorb and release. Secondly, since it has a large amount of moisture absorption at low temperature and a large amount of release at high temperature, it has a high humidity control function. Thirdly, since the range of moisture absorption amount depending on the temperature is large, it has an effect that the moisture content in the gas can be controlled in a wide range depending on the temperature.

Hereinafter, the present invention will be further described with reference to examples.

Example 1 355.2 g of N-acryloylpyrrolidine, 1.8 g of N, N'-methylenebisacrylamide and 153 g of calcium chloride were added to 1,17 of water.
An aqueous solution of N-acryloylpyrrolidine containing 0.35 wt% N, N'-methylenebisacrylamide and 30 wt% calcium chloride was prepared by dissolving in 0 g. After cooling the aqueous solution to 10 ° C., transfer to a 2 l stainless steel dewar and
Nitrogen gas was bubbled for 1 hour using a ball filter at a flow rate of / min. Then, a solution prepared by dissolving 1.79 g of ammonium persulfate in 10 g of water and sodium bisulfite were added to the aqueous solution.
A solution prepared by dissolving 81 g in 10 g of water was simultaneously added to polymerize the aqueous solution adiabatically. The obtained gel was chopped and dried, and then further pulverized to collect a 20 to 100 mesh fraction, which was used as a sample. 10 g of the sample powder was sprayed on a 200-mesh stainless steel wire net, the temperature was kept at 10 ° C. in a constant temperature and humidity chamber adjusted to 98% relative humidity, and the amount of moisture absorption per 1 g of the sample powder was measured, 0.55g after 1 hour, 2 hours later
0.80g, 0.96g after 3 hours, 1.07g after 4 hours, and 10
After an hour, it had absorbed 1.55 g of water. Then, the moisture-absorbed sample powder was allowed to stand in a constant temperature and humidity chamber adjusted to a temperature of 40 ° C. and a relative humidity of 40%. After 1 hour, the water content per 1 g of the sample powder was 0.42 g. It releases 1.13g of water per 1g of powder, and after 2 hours
After 1.27 g and 3 hours, 1.30 g of water had been released. Using the sample powder, moisture absorption and desorption were repeated 10 times,
There was no change in the amount of absorbed moisture and the amount of released moisture, and the sample powder before and after the test was observed with a microscope, but the powder particles were not crushed.

Examples 2 to 9 By the same method as in Example 1, sample powders having the compositions shown in Table 1 were obtained. Using the sample powder, the amount of moisture absorbed and the amount of moisture released per 1 g of the sample powder were measured by the same method as in Example 1, and the results shown in Table 1 were obtained.

Comparative Example 1 By the same method as in Example 1, 99.5 wt% of N-acryloylpyrrolidine and 0.5 of N, N'-methylenebisacrylamide were used.
A sample powder consisting of wt% was obtained. Using the sample powder, the amount of moisture absorption and the amount of moisture released were measured in the same manner as in Example 1. The amount of moisture absorption per 1 g of sample powder was 10 hours later.
It was 0.60 g, and the amount of moisture released was 0.51 g after 1 hour.

Comparative Example 2 When 10 g of calcium chloride was weighed on a petri dish and the amount of moisture absorption and the amount of moisture released were measured by the same method as in Example 1, the amount absorbed per 1 g of calcium chloride was 2.58 g after 10 hours. At this moisture absorption amount, calcium chloride was in an aqueous solution state. The amount of moisture released was 0.80 g after 3 hours.

Examples 10 to 12 Sample powders having the compositions shown in Table 2 were obtained in the same manner as in Example 1 using nylon fibers having a length of 1 mm and a thickness of 3 denier. Using the sample powder, the amount of moisture absorbed and the amount of moisture released per 1 g of the sample powder were measured by the same method as in Example 1, and the results shown in Table 2 were obtained. Moisture absorption and desorption were repeated 10 times using the sample powder, but there was no change in the amount of moisture absorption and desorption, and the sample powder before and after the test was observed with a microscope, but crushing of the powder particles, etc. occurred. There wasn't.

Examples 13 to 14 Nonwoven fabric made of polyester having a size of 15 × 15 cm (weight 1.35)
g) on the surface of the sample powder obtained in Examples 11 and 12
2.30 g was evenly dispersed, the same non-woven fabric was further laid thereon, and the upper and lower non-woven fabrics were heat-sealed in a 1.5 cm square grid pattern to prepare a non-woven fabric sample in which sample powder was sandwiched. Using the sample, the amount of moisture absorption and the amount of moisture released per 1 g of the sample were measured in the same manner as in Example 1 and Table 3
The results shown in are obtained. Absorption and desorption of moisture using this sample
After repeating 10 times, the shape, appearance, moisture absorption amount, moisture release amount, etc. of the sample did not change from those before the test.

Examples 15 to 19 Using 2.30 g of the sample powder having the composition shown in Table 4 obtained by the same method as in Example 10, the same method as in Example 13 was performed to sandwich the sample powder. A sample was prepared. Using the sample, the amount of moisture absorption and the amount of moisture released per 1 g of the sample were measured in the same manner as in Example 1,
The results shown in Table 4 were obtained.

Examples 20-22 N-acryloylpyrrolidine 100 g and 2 in distilled water 1700 g
-Adding 3 g of sodium acrylamido-2-phenylpropanesulfonate and replacing the inside of the reactor with nitrogen,
Heated to 60 ° C. Then, 0.6 g of potassium persulfate was added to the reaction solution to start the polymerization, and the polymerization was carried out for 3 hours. As the polymerization proceeded, the reaction solution gradually became cloudy and became an emulsion. Then, 50 g of acrylonitrile was added to the reaction solution by using a pump over 30 minutes. After the addition was complete, the reaction was allowed to react for another 3 hours at 60 ° C. The obtained emulsion solution became an aqueous solution when the temperature became 50 ° C or lower. A solution prepared by dissolving calcium chloride in the polymer aqueous solution is 15 cm × 15
cm-sized polypropylene-rayon non-woven fabric (weight
1.33 g) was applied on both the front and back sides, and then dried at 80 ° C. for 4 hours to prepare a nonwoven fabric sample coated with the amounts of the polymer shown in Table 5 and calcium chloride. Using the sample, the amount of moisture absorbed and the amount of moisture released per 1 g of the sample were measured in the same manner as in Example 1, and the results shown in Table 5 were obtained. Moisture absorption / moisture release was repeated 10 times using the sample, but there was no change in the shape, appearance, moisture absorption / moisture release amount, etc. of the sample from before the test.

Example 23 1 g of the sample powder obtained in Comparative Example 1 was uniformly sprayed with 10 g of a 10 wt% calcium chloride aqueous solution using a sprayer so as to be absorbed. A sample of the non-woven fabric sandwiched by the same method as in Example 13 using the sample powder was allowed to stand still in a constant temperature and humidity chamber adjusted to a temperature of 40 ° C. and a relative humidity of 40%. Had released 7.3 g of water, and the amount absorbed per 1 g of the sample was 0.36 g. Then, this sample was allowed to stand still in a constant temperature and humidity chamber adjusted to a temperature of 10 ° C. and a relative humidity of 98%. After 10 hours, 1.75 g of water was absorbed per 1 g of the sample.

Example 24 355.2 g of N-acryloylpyrrolidine, 1.8 g of N, N'-methylenebisacrylamide, 153 g of lithium chloride and 1170 g of water.
To prepare an aqueous solution of N-acryloylpyrrolidine containing 0.35 wt% of N, N'-methylenebisacrylamide and 30 wt% of lithium chloride. After cooling the aqueous solution to 10 ° C., it was transferred to a 2 l stainless steel dewar and nitrogen gas was bubbled for 1 hour using a ball filter at a flow rate of 1 / min. Then, the aqueous solution was added with ammonium persulfate 1.79.
A solution obtained by dissolving g in 10 g of water and a solution prepared by dissolving 0.81 g of sodium hydrogen sulfite in 10 g of water were simultaneously added to polymerize the aqueous solution adiabatically. The obtained gel was chopped and dried, and then further pulverized to collect a 20 to 100 mesh fraction, which was used as a sample. 10 g of the sample powder was sprayed on a 200-mesh stainless steel wire net, and the sample powder was allowed to stand in a thermo-hygrostat adjusted to a temperature of 10 ° C. and a relative humidity of 98%. 0.49g after 2 hours and 0.68g after 2 hours,
0.80g after 3 hours, 0.88g after 4 hours, and after 10 hours
It absorbed 1.26 g of water. Then, the moisture-absorbed sample powder was allowed to stand in a thermo-hygrostat adjusted to a temperature of 40 ° C. and a relative humidity of 40%, and after 1 hour, the water content per 1 g of the sample powder was 0.36 g. It releases 0.90g of water per 1g, and 1.00g after 2 hours,
After 3 hours, 1.03 g of water had been released.

Examples 25-27 355.2 g of N-acryloylpyrrolidine, 1.8 g of N, N'-methylenebisacrylamide and 357.0 g of calcium chloride were added to water.
107.1 g of nylon fiber having a length of 1 mm and a thickness of 3 denier was suspended in 1170 g and suspended in the aqueous solution, and polymerization was carried out in the same manner as in Example 24 using ammonium persulfate and sodium hydrogen sulfite as a polymerization initiator. A polymer powder was obtained and sieved in exactly the same manner as in Example 24 to obtain a fraction larger than 100 mesh as a sample powder.

Then, 2.30 g of the sample powder is evenly dispersed on the surface of a polyester non-woven fabric (weight: 1.35 g) having a size of 15 cm × 15 cm, and the same non-woven fabric is further laid on it to form a 1.5 cm square grid. A nonwoven fabric sample was sandwiched with the sample powder by heat-sealing the nonwoven fabric. Using the sample, the moisture absorption amount per 1 g of the inorganic salt-containing polymer after standing for 12 hours in the temperature and humidity conditions shown in Table 6 was measured, and the results are shown in Table 6.

Claims (1)

[Claims] 1. Represented by the general formula (I) or (II) (In the above formula, R ₁ is a hydrogen atom or a methyl group, R ₂ is a hydrogen atom,
A methyl group or an ethyl group, and R ₃ is a methyl group, an ethyl group or a propyl group. ) (In the above formula, R ₁ is a hydrogen atom or a methyl group, A is CH _{2 n} and n is 4 to 6 or CH _{2 2} OCH _{2 2.} ) N-alkyl or N-alkylene-substituted (meth) acrylamide alone or An improved water vapor absorbing and releasing agent obtained by integrating a hygroscopic inorganic compound with a polymer obtained by insolubilizing a copolymer or a copolymer with another copolymerizable monomer in water.